Introduction

Traumatic brain injury is one of the main causes of deaths, disabilities, and hospitalization in the world. In the USA, around 30% of all injury-related deaths are due to traumatic brain injury.1 Globally, traumatic brain injury affects the lives of about 10 million people each year.2 It happened as the brain tissue is damaged by an external force, the result of direct impact, rapid acceleration or deceleration, a piercing object, and blast waves from an explosion.3 Visual impairment, cognitive dysfunction, hearing loss, and mental health disorders are among the most common complications affecting traumatic brain injury patients and their families. The pathophysiology of traumatic brain injury is not clear since the structure of the brain is complex with many cell types such as neurons, astrocytes, oligodendrocytes, microglia, and multiple subtypes of these cells. Traumatic brain injury occurs in two phases. These are primary (acute) and secondary (late) brain injuries. The primary injury is the initial blow to the head; in this phase, brain tissue and cells such as neurons, glial cells, endothelial cells, and the bloodbrain barrier are damaged by mechanical injury. The secondary injury occurs after primary injury and in these late phases, several toxins are released from the injured cells leading to the formation of cytotoxic cascades, which increase the initial brain damage.4 The primary brain injury causes the dysfunction of the bloodbrain barrier and initiates local inflammation and secondary neuronal injury. In addition, severe and long-term inflammation causes severe neurodegenerative and inflammatory diseases. Repairing of tissue damage needs the inhibition of secondary injury and rapid regeneration of injured tissue.5 Depending on the nature of the injury, neurons and neuroglial cells may be damaged; excessive bleeding may happen, axons may be destroyed and a contusion may occur.6 Moreover, the pathogenesis of traumatic brain injury involves bloodbrain barrier damage, neural inflammation, and diffuse neuronal degeneration.7 Unlike other organs, it has long been thought that mature brain tissue cannot be able to repair itself after injury.8 However, the current research indicated that multipotent neural stem/progenitor cells are residing in some areas of the brain throughout the lifespan of an animal, implying the mature brains ability to produce new neurons and neuroglial cells.9 In the previous decades, several studies have shown that the mature neurons in the hippocampal dentate gyrus of the brain play significant roles in hippocampal-induced learning and memory activities,9 while new olfactory interneurons produced from the subventricular zone are essential for the appropriate functioning of the olfactory bulb network and some specific olfactory behaviors.10 After traumatic brain injuries, clinical evidence indicated that endogenous neural progenitor cells might play an important role in regenerative medicine to treat brain injury because an increased neurogenic regeneration ability has been reported in different types of brain injury models of animal and human studies.11 Nowadays, there is a new therapeutic approach for traumatic brain injury that involves the use of stem cells for neural regeneration and restoration. Exogenous stem cell transplantation has been found to accelerate immature neuronal development and increase endogenous cellular proliferation in the damaged brain region.12 A better understanding of the endogenous neural stem cells regenerative ability as well as the effect of exogenous neural stem cells on proliferation and differentiation may help researchers better understand how to increase functional recovery and brain tissue repair following injury. Therefore, in this study, we discussed the therapeutic effects of stem cells in the repair of traumatic brain injury.

Traumatic brain injury causes severe stress on the brain, making it extremely hard to keep appropriate cognitive abilities. Even though many organs in the body, for example, the skin, can regenerate following injury, the brain tissue may not easily repair. In the adult brain, endogenous neural stem cells are primarily localized to the subventricular zone of the lateral ventricles and the subgranular zone of the hippocampal dentate gyrus.13 In the subventricular zone, neural stem/progenitor cells generate neuronal and oligodendroglial progenies.14 Most of the new neurons produced from the subventricular zone migrate via the rostral migratory stream, eventually becoming olfactory interneurons in the olfactory bulb.15 A few subventricular zone-derived new neurons travel into cortical areas for an unknown cause but may be related to tissue repair or renewal mechanisms.16 Similarly, newly produced dentate gyrus cells travel laterally into the dentate granule cell layer and become fully mature in a few weeks through a process known as adult hippocampus neurogenesis.17 However, it is still unknown whether these neural stem cells in the subventricular zone and dentate gyrus regions can replace the lost neurons following injury.

So far, several studies have assessed the degree of neurogenesis in these two areas and have demonstrated that significant numbers of new cells are continuously generated.9,18 For example, the rat dentate gyrus generates about 9000 new cells each day or 270,000 cells every month.18 A current clinical finding indicated that the whole granular cell population in the deep layer and half of the superficial layer of the olfactory bulb were replaced by newly produced mature neurons for a year.19 A similar study also revealed that adult-produced neurons account for around 10% of the overall number of dentate granule cells in the hippocampus and they are uniformly distributed along the anterior-posterior axis of the dentate gyrus.19 After the finding of continuous adult neurogenesis during the lifetime in the adult animal brain, the functional roles and the significance of this adult neurogenesis, mainly hippocampal neurogenesis concerning learning and memory processes, have been widely explored. Previous studies showed factors that increase hippocampal neurogenesis such as exposure to enriched environments, physical activity, or growth factor therapy may improve cognitive abilities.2022

The newly formed granular cells in the mature dentate gyrus can become functional neurons in the normal hippocampus by demonstrating passive membrane characteristics, generating action potentials, and receiving functional synaptic inputs, as seen in the adult dentate gyrus neurons.23 For instance, mouse strains hereditarily having poor levels of neurogenesis carry out low learning activities than those with a higher level of baseline neurogenesis.2325 A variety of physical and chemical signals influence the proliferation and maturational destiny of cells in the subventricular zone and dentate gyrus. For instance, biochemical variables including serotonin, glucocorticoids, ovarian hormones, and growth factors strongly regulate the proliferative response, implying that cell proliferation in these areas has a significant physiological role.26,27 Besides, physical factors such as exercise and stress produce changes in cell proliferation implying a significant role in network adaptation.28,29 For example, physical exercise might cognitively and physically enhance the production of cells and neurogenesis within the subventricular zone and dentate gyrus, but stress inhibits this type of cellular activity. Furthermore, the physiologic role of these new cells depends on the number of cells being produced, survival rate, differentiation ability, and integration of cells into existing neuronal circuity.24,30

The subventricular zone and hippocampus contain neural stem cells that respond to a variety of stimuli. Different kinds of experimental traumatic brain injury models such as fluid percussive injury,31,32 controlled cortical impact injury,33,34 closed-head weight drop injury,35 and acceleration-impact injury36 have shown increased neural stem cells activation. All of these experimental studies have shown the most prevalent and notable endogenous cell response after traumatic brain injury is an elevated cell proliferation within neurogenic areas of the dentate gyrus and subventricular zone. It is well accepted that enhanced production of new neurons following the traumatic brain injury was detected predominantly in the hippocampus in the more seriously injured animals in many experimental studies.37 More studies have discovered that injury-enhanced new granule neurons send out axonal projections into the targeted CA3 region implying their integration into the existing hippocampal circuitry,37,38 and this injury-induced endogenous neurogenic stem cells response is directly associated with the inherent cognitive functional recovery after traumatic brain injury of rodents.39,40

In the human brain, the extent and physiology of the adult neural generation are not well understood. A study on human brain samples taken from the autopsy revealed neural stem cells with proliferative ability have been observed within the subventricular zone and the hippocampus.41,42 Conversely, a more recent study has shown that neurogenesis in the subventricular zone and movement of new neurons from the subventricular zone to the olfactory bulbs and neocortex are restricted and only seen in the early childhood period.43,44 Therefore, credible evidence of traumatic brain injury-initiated neurogenesis in the human brain is inadequate because of the difficulties of collecting human brain samples and technical challenges to birth-dating neural stem cells.

After traumatic brain injury, injury-initiated neural cell loss is permanent. Given the restricted amount of endogenous neurogenic stem cells, neural transplantation supplementing exogenous stem cells to the damaged brain tissue is a potential treatment for post-traumatic brain injury regeneration.45 Especially, the transplanted cells will not only be able to replace the damaged neural cells but also give neurotrophic support in hopes of reestablishing and stabilizing the damaged brain tissue.45 Clinical evidence revealed intervention with stem cell secretome may significantly improve neural inflammation after traumatic brain injury and other neurological deficits in humans.46 Besides, the combined effects of bioscaffold and exosomes can aid in the transportation of stem cells to damaged areas as well as enhance their survival and facilitate successful treatment.47 Despite the rapid progression of brain infarction, the decreased proliferation of neural stem cells, and the delayed initiation of neurological recovery were observed in the aged rat model compared with a young rat after stroke, the restorative capability of the brain by stem cell therapy is still present in the aged rat.48 Compared to stem cell monotherapies which are still uniformly failed in clinical practice, combination therapy with hypothermia has potential therapeutic effects on the physiology of the aged brain and may be required for effective protection of the brain following stroke.49 After several years of biomaterials study for regeneration of peripheral nerve, a new 3D printing strategy is developing as a good substitution for nerve autograft over large gap injuries. The applications of 3D printing technologies can help in improving long-distance peripheral nerve regeneration since it is a leading device to give one path for better nerve guidance.50 Up to now, various categories of stem cell therapy have been tested for post-traumatic brain injury. These include embryonic stem cells, adult-derived neural stem cells, mesenchymal stem cells, and induced pluripotent stem cells.

Embryonic stem cells obtained from fetal or embryonic brain tissues are highly considered for neural transplantation because of their ability of plasticity and have the capacity to self-repair and differentiation into all germinal layers. They can differentiate, migrate, and innervate as transplanted into a receiver brain tissue.51 In previous clinical brain injury studies, neural stem cells derived from the embryonic human brain could survive for a long time, migrating to the contralateral cortex and differentiating into mature neural cells and microglia following transplantation into the damaged brain tissue.52 Implanted neurogenic stem cells obtained from human fetal stem cells may differentiate into adult neurons and release growth factors increasing the cognitive functional recovery of the damaged brain.53 Interestingly, the long-term survival rate of transplanted neural stem cells obtained from mice embryonic brains was seen for up to 1 year with a high degree of migration in the damaged brain and maturation into neurons or neuroglial cells along with enhanced motor and spatial learning functions of the brain tissue.5456 In addition, embryonic stem cells expressing growth factors or early differentiated into neurotransmitter expressing adult neurons after in vitro manipulation have revealed improved transplant survival and neuronal differentiation following grafted into the damaged brain, and the receivers have better recovery in motor and cognitive activities.5759 Even though embryonic stem cells have a high rate of survival and plasticity in neuronal transplantation, the ethical concerns, risk of transplant rejection, and the likelihood of teratoma development restrict their therapeutic use for traumatic brain injury.45

Neural stem cells are multipotent cells that can differentiate into neural cells but have a limited ability to differentiate into other tissue types.60 Neurogenic stem cells are located in the subventricular zones of the lateral ventricle, the hippocampal dentate gyrus, and other areas of the brain like the cerebral cortex, amygdala, hypothalamus, and substantia nigra. They could be isolated, developed in culture media, and produce many neural lineages that can be used in the treatment of neurological disorders as an important element of cellular-replacement therapy.61 Adult neural stem cells were transplanted into damaged parts of the brain in a traumatic brain injury rat model. These cells survived the transplantation process and moved to a damaged site when expressing markers for adult microglia and oligodendrocytes.62 Interestingly, one most recent study indicated that Korean red ginseng extract-mediated astrocytic heme oxygenase-1 induction contributes to the proliferation and differentiation of adult neural stem cells by upregulating astrocyteneuronal system cooperation.63 Another study revealed that following neural stem cell transplantation to the hippocampal region, injured rats had developed better cognitive function.64 The administration of combined therapies such as human neural stem/progenitor cells and curcumin-loaded noisome nanoparticles significantly improve brain edema, gliosis, and inflammatory responses in the traumatic brain injury rat model.65 Furthermore, in traumatic brain injury rat models, as neural stem cells were injected intravenously, they resulted in a decreased neurologic impairment and less edema because of the anti-inflammatory and anti-apoptotic features of neural stem cells.60,66 The ideal transplantation timeframe is 714 days,60 beyond which the glial scar forms, restricting perfusion and graft survival.67 The ability to transport cells to the desired location is a key obstacle with neural stem cell transplantation. Neural stem cells can be administered intrathecally, intravenously, and intra-arterial infusion. Conversely, a nanofiber scaffold implantation was proposed by Walker et al as a new strategy to be implemented to give the support essential for cell proliferation, which provides direction to future research.68

Mesenchymal stem cells are multipotent stromal that can differentiate into mesenchymal and non-mesenchymal tissue, such as neural tissue.69 They are obtained from different types of tissues.70 The accessibility, availability, and differentiation ability of these cells have drawn the attention of researchers performing studies in regenerative medicine. A previous study revealed the differentiation capacity of mesenchymal stem cells into neuronal cells. This study found that when rat and human mesenchymal stem cells are exposed to various experimental culture conditions, they can differentiate into neural and neuroglial cells.69 Besides, mesenchymal stem cells have also been demonstrated to enhance the proliferation and differentiation of native neural stem cells; the mechanism of which may be directly associated with chemokines produced by mesenchymal stem cells or indirectly through stimulation of adjacent astrocytes.70 In addition to their capacity to differentiate, mesenchymal stem cells selectively move to damaged tissues in traumatic brain injury rat models, where they develop into neurons and astrocytes and enhance motor function.71 The possible mechanism of action through which this occurs is linked to chemokines, growth factors,72 and adhesion factors, like the vascular cell adhesion molecule (VCAM-1), which permits mesenchymal stem cells to adhere to the endothelium of damaged organ.73 Mesenchymal stem cell transplantation has become a potential and safe treatment of choice for traumatic brain injuries because of its anti-inflammatory capability by regulating leukocyte and inflammatory factors such as IL-6, CRP, and TNF-a.74,75 Treatment with mesenchymal stem cell-derived extracellular vesicles greatly increased neurogenesis and neuroplasticity in a pig model of hemorrhagic stroke and traumatic brain damage.76 Currently, stem cell therapy using mesenchymal stromal cells has been widely investigated in preclinical models and clinical trials for the treatment of several neurological illnesses, including traumatic brain injury. Mesenchymal stem cells investigated for the treatment of traumatic brain injury in these clinical trials include bone marrow-derived stem cells, amnion-derived multipotent progenitor cells, adipose-derived stem cells, umbilical cord-derived stem cells, and peripheral blood-derived stem cells.7779 Those undifferentiated mesenchymal-derived cells have a heterogeneous cell population that includes stem and progenitor cells. They can be stimulated to differentiate into a neuronal cell phenotype in vitro. In the damaged brain tissue, these cells can generate a large number of growth factors, cytokines, and extracellular matrix substances that have neurotrophic or neuroprotective effects.80,81

From all mesenchymal stem cells, the effect of bone marrow-derived mesenchymal stem cells on traumatic brain injury has been fully investigated. According to previous studies, mesenchymal stem cells injected directly into the injured brain, or through intravenous or intra-arterial injections during the acute, sub-acute, or chronic phase following traumatic brain injury, have been shown to significantly reduce neurological abnormalities in motor and cognitive abilities.7779,82 The therapeutic effect of mesenchymal stem cells is mostly because of the bioactive molecules they produced to facilitate the endogenous plasticity and remodeling of the recipient brain tissue instead of direct neural repair as direct neuronal differentiation and long-term viability were rarely seen.80 A more recent study found that the injection of cell-free exosomes obtained from human bone marrow-derived mesenchymal stromal cells can increase the functional recovery of damaged animals after traumatic brain injury.83 Another study used a traumatic rodent model to evaluate the anti-inflammatory and immunoregulatory properties of mesenchymal stem cells. When compared to the control group, neurological function was improved in the treatment groups from 3 to 28 days. Mesenchymal stem cell therapy significantly decreased the amount of microglia or macrophages, neutrophils, CD3 lymphocytes, apoptotic cells in the damaged cortex, and proinflammatory cytokines.81 The main challenge of using mesenchymal stem cells for traumatic brain injury treatment is the long-term possibility of brain malignancy development because of the mesenchymal stromal cells ability to antitumor response suppression.84

In a recent study, seven traumatic brain injury patients were given a mesenchymal stem cells transplant during a cranial operation and then administered a second dose intravenously. At the end of the 6-month follow-up period, patients exhibited better neurological function with no signs of toxicity.85

Recent studies revealed that the administration of exosomes-derived human umbilical cord mesenchymal stem improves sensorimotor function and spatial learning activities in rat models following brain injuries. Furthermore, the applications of these cells extensively decreased proinflammatory cytokine expression via inhibiting the NF-B signaling pathway, reduced neuronal apoptosis, reduced inflammation, and increased neural regeneration ability in the injured cortex of rats following the injuries.86 Human umbilical cord-derived mesenchymal stem cells have better anti-inflammatory activity that may prevent and decrease secondary brain injury caused by the immediate discharge of inflammatory factors following traumatic brain injury.87 In traumatic brain injury rat models, the transplantation of umbilical cord-derived mesenchymal stem cells triggers the trans-differentiation of T-helper 17 into T regulatory, which in turn repairs neurological deficits and improves learning and memory function.88

To see the therapeutic effects of transplanted induced pluripotent stem cells compared to that of embryonic stem cells, Wang et al demonstrated animal models of ischemia and three different treatment options, which consist of pluripotent stem cells, embryonic stem cells, and phosphate-buffered saline for the control. The rodents were given an injection into the left lateral ventricle of the brain. Embryonic stem cell treatment group rodents showed a significant improvement in glucose metabolism within two-week period. However, 1 month following treatment, neuroimaging tests were done and it was revealed that both pluripotent stem cell and embryonic stem cell treatment groups had improved neurologic scores as compared to the control group, suggesting that the treatment groups showed better recovery of their cognitive function. Further investigation indicated that the implanted cells survived and traveled to the area of injury. Finally, the investigator of this study concluded that induced pluripotent stem cells may be a better option than embryonic stem cells.57 Different studies showed that induced pluripotent stem cells improved motor and cognitive function in the host mouse brain tissue, and these cells migrate the injured brain areas from the injection site.89,90 Until now, there are limited studies on induced pluripotent stem cell therapy for brain injuries. This is because of the difficulty of obtaining induced pluripotent stem cells, high therapy costs, and technique limitations.

In preclinical and clinical trials, advanced progress has been made in stem cell-based therapy for traumatic brain injury patients. Various studies reported the therapeutic effect of stem cells for regenerating damaged brain tissue. However, because of the complexity and variability of brain injuries, post-traumatic brain injury neuronal regeneration and repair remain a long-term goal. There are numerous unresolved challenges for successful stem cell treatment. For endogenous restoration via mature neural regeneration, methods guiding the movement of new neuronal cells to the area of damaged tissue and maintaining long-term survival are very important. In stem cell therapy, the inherent features of transplanted cells and the local host micro-environment influences the fate of grafted cells, an appropriate cell source, and a host environment, which are required for effective transplantation. Therefore, these problems should be solved in preclinical traumatic brain injury trials before stem cell-based treatments could be used in the clinic. The therapeutic application of neural stem cell treatment, whether via manipulation of endogenous or implantation of exogenous neural stem cells, is a method that has been shown in multiple studies to have substantial potential to increase brain function recovery in persons suffering from traumatic brain injury-related disability. However, further studies need to be done on the therapeutic application of stem cells for traumatic brain injury due to our poor understanding of possible consequences, unknown ethical issues, routes of administration, and the use of mixed treatment.

All authors declared no conflicts of interest for this study.

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Repair of Traumatic Brain Injury | SCCAA - Dove Medical Press

Fibrosis is the thickening of various tissues caused by the deposition of fibrillar extracellular matrix (ECM) in tissues and organs as part of the bodys wound healing response to various forms of damage. When accompanied by chronic inflammation, fibrosis can go into overdrive and produce excess scar tissue that can no longer be degraded. This process causes many diseases in multiple organs, including lung fibrosis induced by smoking or asbestos, liver fibrosis induced by alcohol abuse, and heart fibrosis often following heart attacks. Fibrosis can also occur in the bone marrow, the spongy tissue inside some bones that houses blood-producing hematopoietic stem cells (HSCs) and can lead to scarring and the disruption of normal functions.

Chronic blood cancers known as myeloproliferative neoplasms (MPNs) are one example, in which patients can develop fibrotic bone marrow, or myelofibrosis, that disrupts the normal production of blood cells. Monocytes, a type of white blood cell belonging to the group of myeloid cells, are overproduced from HSCs in neoplasms and contribute to the inflammation in the bone marrow environment, or niche. However, how the fibrotic bone marrow niche itself impacts the function of monocytes and inflammation in the bone marrow was unknown.

Now, a collaborative team from Penn, Harvard, the Dana-Farber Cancer Institute (DFCI), and Brigham and Womens Hospital has created a programmable hydrogel-based in vitro model mimicking healthy and fibrotic human bone marrow. Combining this system with mouse in vivo models of myelofibrosis, the researchers demonstrated that monocytes decide whether to enter a pro-inflammatory state and go on to differentiate into inflammatory dendritic cells based on specific mechanical properties of the bone marrow niche with its densely packed ECM molecules. Importantly, the team found a drug that could tone down these pathological mechanical effects on monocytes, reducing their numbers as well as the numbers of inflammatory myeloid cells in mice with myelofibrosis. The findings are published in Nature Materials.

We found that stiff and more elastic slow-relaxing artificial ECMs induced immature monocytes to differentiate into monocytes with a pro-inflammatory program strongly resembling that of monocytes in myelofibrosis patients, and the monocytes to differentiate further into inflammatory dendritic cells, says co-first author Kyle Vining, who recently joined Penn.More viscous fast-relaxing artificial ECMs suppressed this myelofibrosis-like effect on monocytes. This opened up the possibility of a mechanical checkpoint that could be disrupted in myelofibrotic bone marrow and also may be at play in other fibrotic diseases. Vining will be appointedassistant professor of preventive and restorative sciences in theSchool of Dental Medicine and the Department of Materials Sciences in theSchool of Engineering and Applied Science, pending approval by Penn Dental Medicines personnel committees and the Provosts office.

Vining worked on the study as a postdoctoral fellow at Harvard in the lab of David Mooney. Our study shows that the differentiation state of monocytes, which are key players in the immune system, is highly regulated by mechanical changes in the ECM they encounter, says Mooney, who co-led the study with DFCI researcher Kai Wucherpfennig. Specifically, the ECMs viscoelasticity has been a historically under-appreciated aspect of its mechanical properties that we find correlates strongly between our in vitro and the in vivo models and human disease. It turns out that myelofibrosis is a mechano-related disease that could be treated by interfering with the mechanical signaling in bone marrow cells.

Mooney is also the Robert P. Pinkas Family Professor of Bioengineering at Harvard and leads the Wyss Institutes Immuno-Materials Platform. Wucherpfennig is director of DFCIs Center for Cancer Immunotherapy Research, professor of neurobiology at Brigham and Harvard Medical School, and an associate member of the Broad Institute of MIT and Harvard. Mooney, together with co-senior author F. Stephen Hodi, also heads the Immuno-engineering to Improve Immunotherapy (i3) Center, which aims to create new biomaterials-based approaches to enhance immune responses against tumors. The new study follows the Centers road map. Hodi is director of the Melanoma Center and The Center for Immuno-Oncology at DFCI and professor of medicine at Harvard Medical School.

The mechanical properties of most biological materials are determined by their viscoelastic characteristics. Unlike purely elastic substances like a vibrating quartz, which store elastic energy when mechanically stressed and quickly recover to their original state once the stress is removed, slow-relaxing viscoelastic substances also have a viscous component. Like the viscosity of honey, this allows them to dissipate stress under mechanical strain by rapid stress relaxation. Viscous materials are thus fast-relaxing materials in contrast to slow-relaxing purely elastic materials.

The team developed an alginate-based hydrogel system that mimics the viscoelasticity of natural ECM and allowed them to tune the elasticity independent from other physical and biochemical properties. By tweaking the balance between elastic and viscous properties in these artificial ECMs, they could recapitulate the viscoelasticity of healthy and scarred fibrotic bone marrow, whose elasticity is increased by excess ECM fibers. Human monocytes placed into these artificial ECMs constantly push and pull at them and in turn respond to the materials mechanical characteristics.

Next, the team investigated how the mechanical characteristics of stiff and elastic hydrogels compared to those in actual bone marrow affected by myelofibrosis. They took advantage of a mouse model in which an activating mutation in a gene known as Jak2 causes MPN, pro-inflammatory signaling in the bone marrow, and development of myelofibrosis, similar to the disease process in human patients with MPN. When they investigated the mechanical properties of bone marrow in the animals femur bones, using a nanoindentation probe, the researchers measured a higher stiffness than in non-fibrotic bone marrow. Importantly, we found that the pathologic grading of myelofibrosis in the animal model was significantly correlated with changes in viscoelasticity, said co-first author Anna Marneth, who spearheaded the experiments in the mouse model as a postdoctoral fellow working with Ann Mullally, a principal investigator at Brigham and DFCI, and another senior author on the study.

An important question was whether monocytes response to the mechanical impact of the fibrotic bone marrow niche could be therapeutically targeted. The researchers focused on an isoform of the phosphoinositide 3-kinase (PI3K)-gamma protein, which is specifically expressed in monocytes and closely related immune cells. PI3K-gamma is known for regulating the assembly of a cell-stiffening filamentous cytoskeleton below the cell surface that expands in response to mechanical stress, which the team also observed in monocytes encountering a fibrotic ECM. When they added a drug that inhibits PI3K-gamma to stiff elastic artificial ECMs, it toned down their pro-inflammatory response and, when given as an oral treatment to myelofibrosis mice, significantly lowered the number of monocytes and dendritic cells in their bone marrow.

This research opens new avenues for modifying immune cell function in fibrotic diseases that are currently difficult to treat. The results are also highly relevant to human cancers with a highly fibrotic microenvironment, such as pancreatic cancer, says Wucherpfennig.

Adapted from a press release written by Benjamin Boettner of the Wyss Institute for Biologically Inspired Engineering at Harvard University.

Other authors on the study are Harvards Kwasi Adu-Berchie, Joshua M. Grolman, Christina M. Tringides, Yutong Liu, Waihay J. Wong, Olga Pozdnyakova, Mariano Severgnini, Alexander Stafford, and Georg N. Duda.

The study was funded by the National Cancer Institute of the National Institutes of Health (Grant CA214369), National Institute of Dental & Craniofacial Research of the National Institutes of Health (grants DE025292 and DE030084), Food and Drug Administration (Grant FD006589), and Harvard University Materials Research Science and Engineering Center (Grant DMR 1420570).

Link:
Deconstructing the mechanics of bone marrow disease | Penn Today - Penn Today

Under embargo until Thursday 14 July 2022 at 16:00 (London time), 14 July 2022 at 11:00 (US Eastern Time).

Newswise The discovery of 14 inherited genetic changes which significantly increase the risk of a person developing a symptomless blood disorder associated with the onset of some types of cancer and heart disease is published today in Nature Genetics. The finding, made in one of the largest studies of its kind through genetic data analysis on 421,738 people, could pave the way for potential new approaches for the prevention and early detection of cancers including leukaemia.

Led by scientists from the Universities of Bristol and Cambridge, the Wellcome Sanger Institute, the Health Research Institute of Asturias in Spain, and AstraZeneca, the study reveals that specific inherited genetic changes affect the likelihood of developing clonal haematopoiesis, a common condition characterised by the development of expanding clones of multiplying blood cells in the body, driven by mutations in their DNA.

Although symptomless, the disorder becomes ubiquitous with age and is a risk factor for developing blood cancer and other age-related diseases. Its onset is a result of genetic changes in our blood-making cells.

All human cells acquire genetic changes in their DNA throughout life, known as somatic mutations, with a specific subset of somatic mutations driving cells to multiply. This is particularly common in professional blood-making cells, known as blood stem cells, and results in the growth of populations of cells with identical mutations known as clones.

Using data from the UK Biobank, a large-scale biomedical database and research resource containing genetic and health information from half a million UK participants, the team were able to show how these genetic changes relate not only to blood cancers but also to tumours that develop elsewhere in the body such as lung, prostate and ovarian cancer.

The team found that clonal haematopoiesis accelerated the process of biological ageing itself and influenced the risk of developing atrial fibrillation, a condition marked by irregular heartbeats.

The findings also clearly established that smoking is one of the strongest modifiable risk factors for developing the disorder, emphasising the importance of reducing tobacco use to prevent the conditions onset and its harmful consequences.

Dr Siddhartha Kar, UKRI Future Leaders Fellow at the University of Bristol and one of the studys lead authors from Bristols MRC Integrative Epidemiology Unit(IEU), said: Our findings implicate genes and the mechanisms involved in the expansion of aberrant blood cell clones and can help guide treatment advances to avert or delay the health consequences of clonal haematopoiesis such as progression to cancer and the development of other diseases of ageing.

Professor George Vassiliou, Professor of Haematological Medicine at the University of Cambridge and one of the studys lead authors, added: Our study reveals that the cellular mechanisms driving clonal haematopoiesis can differ depending on the mutated gene responsible. This is a challenge as we have many leads to follow, but also an opportunity as we may be able to develop treatments specific to each of the main subtypes of this common phenomenon.

Dr Pedro M. Quiros, formerly researcher at the Wellcome Sanger Institute and the University of Cambridge, and now Group Leader at the Health Research Institute of Asturias (Spain) and another of the studys lead authors says: We were particularly pleased to see that some of the genetic pathways driving clonal haematopoiesis appear to be susceptible to pharmacological manipulation and represent prioritised targets for the development of new treatments.

The study was funded by UK Research and Innovation (UKRI), Cancer Research UK (CRUK), Wellcome, the Royal Society, the Carlos III Health Institute, the Leukaemia and Lymphoma Society, and the Rising Tide Foundation for Clinical Cancer Research.

Paper

Genome-wide analyses of 200,453 individuals yield new insights into the causes and consequences of clonal hematopoiesis by Kar SP, et al. in Nature Genetics.

Ends

Further information:

Clonal haematopoiesis is the development of mutations in genes involved in blood cell production. It is diagnosedwhen a test on a person's blood or bone marrow sample shows that blood cells are carrying one of the genetic mutations associated with the condition. Clonal haematopoiesis becomes increasingly common with age, affecting more than one in every ten individuals older than 60 years.

Notes to editors

Paper: an embargoed copy of the paper is available to download here.

Issued by the University of Bristol Media Team.

Continued here:
Scientists Discover Genes That Affect the Risk of Developing Pre-Leukemia - Newswise

In molecular biologist David Sinclair's lab at Harvard Medical School, old mice are growing young again.

Using proteins that can turn an adult cell into a stem cell, Sinclair and his team have reset aging cells in mice to earlier versions of themselves. In his team's first breakthrough, published in late 2020, old mice with poor eyesight and damaged retinas could suddenly see again, with vision that at times rivaled their offspring's.

"It's a permanent reset, as far as we can tell, and we think it may be a universal process that could be applied across the body to reset our age," said Sinclair, who has spent the last 20 years studying ways to reverse the ravages of time.

"If we reverse aging, these diseases should not happen. We have the technology today to be able to go into your hundreds without worrying about getting cancer in your 70s, heart disease in your 80s and Alzheimer's in your 90s." Sinclair told an audience at Life Itself, a health and wellness event presented in partnership with CNN.

"This is the world that is coming. It's literally a question of when and for most of us, it's going to happen in our lifetimes," Sinclair told the audience.

"His research shows you can change aging to make lives younger for longer. Now he wants to change the world and make aging a disease," said Whitney Casey, an investor who is partnering with Sinclair to create a do-it-yourself biological age test.

While modern medicine addresses sickness, it doesn't address the underlying cause, "which for most diseases, is aging itself," Sinclair said. "We know that when we reverse the age of an organ like the brain in a mouse, the diseases of aging then go away. Memory comes back; there is no more dementia.

"I believe that in the future, delaying and reversing aging will be the best way to treat the diseases that plague most of us."

A reset button

In Sinclair's lab, two mice sit side by side. One is the picture of youth, the other gray and feeble. Yet they are brother and sister, born from the same litter -- only one has been genetically altered to age faster.

If that could be done, Sinclair asked his team, could the reverse be accomplished as well? Japanese biomedical researcher Dr. Shinya Yamanaka had already reprogrammed human adult skin cells to behave like embryonic or pluripotent stem cells, capable of developing into any cell in the body. The 2007 discovery won the scientist a Nobel Prize, and his "induced pluripotent stem cells," soon became known as "Yamanaka factors."

However, adult cells fully switched back to stem cells via Yamanaka factors lose their identity. They forget they are blood, heart and skin cells, making them perfect for rebirth as "cell du jour," but lousy at rejuvenation. You don't want Brad Pitt in "The Curious Case of Benjamin Button" to become a baby all at once; you want him to age backward while still remembering who he is.

Labs around the world jumped on the problem. A study published in 2016 by researchers at the Salk Institute for Biological Studies in La Jolla, California, showed signs of aging could be expunged in genetically aged mice, exposed for a short time to four main Yamanaka factors, without erasing the cells' identity.

But there was a downside in all this research: In certain situations, the altered mice developed cancerous tumors.

Looking for a safer alternative, Sinclair lab geneticist Yuancheng Lu chose three of the four factors and genetically added them to a harmless virus. The virus was designed to deliver the rejuvenating Yamanaka factors to damaged retinal ganglion cells at the back of an aged mouse's eye. After injecting the virus into the eye, the pluripotent genes were then switched on by feeding the mouse an antibiotic.

"The antibiotic is just a tool. It could be any chemical really, just a way to be sure the three genes are switched on," Sinclair said. "Normally they are only on in very young developing embryos and then turn off as we age."

Amazingly, damaged neurons in the eyes of mice injected with the three cells rejuvenated, even growing new axons, or projections from the eye into the brain. Since that original study, Sinclair said his lab has reversed aging in the muscles and brains of mice and is now working on rejuvenating a mouse's entire body.

"Somehow the cells know the body can reset itself, and they still know which genes should be on when they were young," Sinclair said. "We think we're tapping into an ancient regeneration system that some animals use -- when you cut the limb off a salamander, it regrows the limb. The tail of a fish will grow back; a finger of a mouse will grow back."

That discovery indicates there is a "backup copy" of youthfulness information stored in the body, he added.

"I call it the information theory of aging," he said. "It's a loss of information that drives aging cells to forget how to function, to forget what type of cell they are. And now we can tap into a reset switch that restores the cell's ability to read the genome correctly again, as if it was young."

While the changes have lasted for months in mice, renewed cells don't freeze in time and never age (like, say, vampires or superheroes), Sinclair said. "It's as permanent as aging is. It's a reset, and then we see the mice age out again, so then we just repeat the process.

"We believe we have found the master control switch, a way to rewind the clock," he added. "The body will then wake up, remember how to behave, remember how to regenerate and will be young again, even if you're already old and have an illness."

Science already knows how to slow human aging

Studies on whether the genetic intervention that revitalized mice will do the same for people are in early stages, Sinclair said. It will be years before human trials are finished, analyzed and, if safe and successful, scaled to the mass needed for a federal stamp of approval.

While we wait for science to determine if we too can reset our genes, there are many other ways to slow the aging process and reset our biological clocks, Sinclair said.

"The top tips are simply: Focus on plants for food, eat less often, get sufficient sleep, lose your breath for 10 minutes three times a week by exercising to maintain your muscle mass, don't sweat the small stuff and have a good social group," Sinclair said.

What controls the epigenome? Human behavior and one's environment play a key role. Let's say you were born with a genetic predisposition for heart disease and diabetes. But because you exercised, ate a plant-focused diet, slept well and managed your stress during most of your life, it's possible those genes would never be activated. That, experts say, is how we can take some of our genetic fate into our own hands.

Cutting back on food -- without inducing malnutrition -- has been a scientifically known way to lengthen life for nearly a century. Studies on worms, crabs, snails, fruit flies and rodents have found restricting calories "delay the onset of age-related disorders" such as cancer, heart disease and diabetes, according to the National Institute on Aging. Some studies have also found extensions in life span: In a 1986 study, mice fed only a third of a typical day's calories lived to 53 months -- a mouse kept as a pet may live to about 24 months.

Studies in people, however, have been less enlightening, partly because many have focused on weight loss instead of longevity. For Sinclair, however, cutting back on meals was a significant factor in resetting his personal clock: Recent tests show he has a biological age of 42 in a body born 53 years ago.

"I've been doing a biological test for 10 years now, and I've been getting steadily younger for the last decade," Sinclair said. "The biggest change in my biological clock occurred when I ate less often -- I only eat one meal a day now. That made the biggest difference to my biochemistry."

Additional ways to turn back the clock

Sinclair incorporates other tools into his life, based on research from his lab and others. In his book "Lifespan: Why We Age and Why We Don't Have To," he writes that little of what he does has undergone the sort of "rigorous long-term clinical testing" needed to have a "complete understanding of the wide range of potential outcomes." In fact, he added, "I have no idea if this is even the right thing for me to be doing."

With that caveat, Sinclair is willing to share his tips: He keeps his starches and sugars to a minimum and gave up desserts at age 40 (although he does admit to stealing a taste on occasion). He eats a good amount of plants, avoids eating other mammals and keeps his body weight at the low end of optimal.

He exercises by taking a lot of steps each day, walks upstairs instead of taking an elevator and visits the gym with his son to lift weights and jog before taking a sauna and a dip in an ice-cold pool. "I've got my 20-year-old body back," he said with a smile.

Speaking of cold, science has long thought lower temperatures increased longevity in many species, but whether it is true or not may come down to one's genome, according to a 2018 study. Regardless, it appears cold can increase brown fat in humans, which is the type of fat bears use to stay warm during hibernation. Brown fat has been shown to improve metabolism and combat obesity.

Sinclair takes vitamins D and K2 and baby aspirin daily, along with supplements that have shown promise in extending longevity in yeast, mice and human cells in test tubes.

One supplement he takes after discovering its benefits is 1 gram of resveratrol, the antioxidant-like substance found in the skin of grapes, blueberries, raspberries, mulberries and peanuts.

He also takes 1 gram of metformin, a staple in the arsenal of drugs used to lower blood sugars in people with diabetes. He added it after studies showed it might reduce inflammation, oxidative damage and cellular senescence, in which cells are damaged but refuse to die, remaining in the body as a type of malfunctioning "zombie cell."

However, some scientists quibble about the use of metformin, pointing to rare cases of lactic acid buildup and a lack of knowledge on how it functions in the body.

Sinclair also takes 1 gram of NMN, or nicotinamide mononucleotide, which in the body turns into NAD+, or nicotinamide adenine dinucleotide. A coenzyme that exists in all living cells, NAD+ plays a central role in the body's biological processes, such as regulating cellular energy, increasing insulin sensitivity and reversing mitochondrial dysfunction.

When the body ages, NAD+ levels significantly decrease, dropping by middle age to about half the levels of youth, contributing to age-related metabolic diseases and neurodegenerative disorders. Numerous studies have shown restoring NAD+ levels safely improves overall health and increases life span in yeast, mice and dogs. Clinical trials testing the molecule in humans have been underway for three years, Sinclair said.

"These supplements, and the lifestyle that I am doing, is designed to turn on our defenses against aging," he said. "Now, if you do that, you don't necessarily turn back the clock. These are just things that slow down epigenetic damage and these other horrible hallmarks of aging.

"But the real advance, in my view, was the ability to just tell the body, 'Forget all that. Just be young again,' by just flipping a switch. Now I'm not saying that we're going to all be 20 years old again," Sinclair said.

"But I'm optimistic that we can duplicate this very fundamental process that exists in everything from a bat to a sheep to a whale to a human. We've done it in a mouse. There's no reason I can think of why it shouldn't work in a person, too."

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The rest is here:
The 'Benjamin Button' effect: Scientists can reverse aging in mice. The goal is to do the same for humans - KITV Honolulu

Affecting one in 5,000 male births worldwide, Duchenne Muscular Dystrophy (DMD) is a fatal genetic disorder that currently doesnt have a cure, but published research conducted at the University of Nevada, Reno School of Medicine shows promise and may lead to the eventual development of a new molecular therapeutic.

The latest, significant research finding, published in Human Molecular Genetics, February 2022, involves the small-molecule sunitinib which has been shown to mitigate DMD-related skeletal muscle disease in a number of ways.

As patients with DMD grow older, muscular dystrophy worsens, causing respiratory and cardiac muscle failure resulting in premature death. There are no effective treatments to prevent DMD-related cardiac failure, however continued research in the lab of UNR Med Professor of Pharmacology Dean Burkin is pointing to protein and molecular-based solutions, including sunitinib which is already FDA approved and used in cancer treatments.

Burkin conducted the latest research with Ph.D. student Ariany Oliveira-Santos. Based on a mouse model, they found that sunitinib improved major negative symptoms that stem from DMD, such as cardiac muscle damage, without depressing the immune system completely. Oliveira-Santos was lead author on the published results. The study was supported by a grant from the Muscular Dystrophy Association and the National Institutes of Health.

Burkins lab focuses mainly on studying two key proteins 71 integrinand laminin and understanding the role they play in muscle development and disease. The lab primarily studies two muscle-damaging diseases: DMD and Laminin-2 related congenital muscular dystrophy (LAMA2-CMD).

Were interested in the biology of the 71 integrin, that's really the central focus of [our research], Burkin said. But we also have other big interests in these muscle diseases where the integrin [protein] is normally found.

Burkin explains that through this translational research, which he also calls the lab bench to bedside approach, researchers attempt to understand the biology of a system as much as possible, and then continue through the development steps that lead to therapeutic treatments.

Patients with DMD lack dystrophin which causes progressive muscle degeneration and weakness. This means the more these muscles are used, the more damage occurs. While there are repair cells in muscles, these cells eventually tire out. Burkin and Oliveira-Santos noted that the heart, an organ being used all the time, does not have this repair system, making the damage severe in cardiac muscles as well. Currently some therapeutic approaches have been beneficial for skeletal muscles but not for the heart; therefore, its important to have a drug or treatment that can target and be beneficial to skeletal and cardiac muscle at the same time, Oliveira-Santos explained.

We looked to the electrical and mechanical function of the heart and both were improved, Oliveira-Santos said. Sunitinib helped the cardiac function [and reduced] cardiac damage, and inflammation. I don't think theres really many drugs out there that do that right now.

Oliveira-Santos remembers wanting to be a scientist as early as eight years old. She went on to earn degrees in Brazil, including a bachelors in biomedicine and a masters in the scientific fields of immunology and pharmacology as they relate to transplant rejection. While earning her masters degree, Burkin was invited to Brazil by Oliveira-Santoss supervisor to give a talk, and the two met in-person and discussed her masters project. At the time, they were studying the same molecule, but in different models, so Oliveira-Santos had read some of Burkins papers.

Oliveira-Santos had always been interested in the physiology and pathology of disease and thought it would be a great area to study for a doctoral degree. She knew Burkin was working in this field, so about five years after their in-person meeting, Oliveira-Santos reached out to Burkin. He told her about an open position in his lab for a Ph.D. student, and their project of understanding the role of an FDA-approved small molecule for the treatment of DMD cardiomyopathy. She felt this project was a good match for what she was looking for and joined the lab in January 2019.

Oliveira-Santos said the mentorship and support shes received from Burkin and the rest of the lab has been invaluable.

Dean is always available to discuss and very happy to help [the lab members] with everything we need, Oliveira-Santos said. Everyone had an important opinion about the project and that was essential for the projects success.

While working in science oftentimes can come with struggles, Oliveira-Santos expressed how much these experiences have taught her.

Being in science is a big challenge, because you have to learn how to deal with problems all the time, she said. There are more failures than success [so] it teaches you how to deal with failure. Failure is normal. You just need to try to find a way around to get a solution.

Oliveira-Santos is set to finish her Ph.D. in Cellular and Molecular Pharmacology & Physiology in the fall 2022.

When I bring a student to the lab, I say I can supply everything but enthusiasm. And that's one thing that Ariany brings in abundance, Burkin said. I'm putting my students in contact with other principal investigators that I know to try and make sure that the next level on their career is achieved. She can go anywhere right now and move forward. The world is her oyster.

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Promising solution to fatal genetic-disorder complications discovered by University professor and Ph.D. candidate - Nevada Today

After reading this article, you should be able to:

A wound is any injury that disrupts the structure of healthy skin tissue caused by chemical, mechanical, biological or thermal trauma. Wounds can be classified as acute or chronic, depending on their period of healing[1]. Acute wounds usually heal without complication within ten days; however, chronic wounds do not undergo normal healing processes, commonly have exaggerated inflammation, persistent infections or microbial biofilm formation and persist longer than six weeks[24]. The most frequent causes of chronic wounds are pressure, diabetes and vascular diseases[5].

Chronic wounds are a global problem, with annual cases rising dramatically owing to the ageing population and increased prevalence of diabetes and obesity[6]. It is estimated that up to 7% of the UK adult population has a chronic wound, costing the NHS 8.3bn each year in staff costs, wound dressings and medication[7]. Individual costs for wound management have been reported to vary, from 358 to 4,684 per patient for a wound that follows the normal healing trajectory, increasing to 831 to 7,886 per patient for a chronic, non-healing wound[7]. The majority of the costs account for GP and nursing time, with infected wounds costing an additional 1.39bn on antibiotics[7].

Results from one study, published in 2020, found that 59% of chronic wounds healed if there was no evidence of infection, compared with 45% if infection was present or suspected[7].Health conditions, such as diabetes mellitus and vascular disease, can predispose people to wounds that are difficult to heal, which can become chronic unless the underlying causes are addressed. For example, people with diabetes are prone to have a high incidence of wounds on their feet, which are slow to heal because of the impact of diabetes on the immune system, circulation and diabetic neuropathy. Complex chronic wounds, such as venous leg ulcers and diabetic ulcers, can significantly impact quality of life, morbidity and mortality[7].

Wound healing is a complex series of physiological reactions and interactions between numerous cell types and chemical mediators[8,9]. It comprises four coordinated and overlapping phases: haemostasis, inflammation, proliferation and remodelling[10].

The Figure below shows the phases of wound healing[11].

The first stage, haemostasis, is instantly activated after injury to stop bleeding at the site and prevent the entry of pathogens. In primary haemostasis, within seconds of an injury occurring, damaged blood vessels vasoconstrict to reduce blood flow through the wound area and diminish blood loss. Platelets adhere to the sub-endothelium of the impaired vessels, initiated by the presence of von Willebrand factor. This binds to glycoprotein Ib receptors on the surface of platelets, causing a conformational change on the platelet surface, activating platelets. These activated platelets release chemicals, such as adenosine diphosphate,serotonin andthromboxane A2, from their dense granules to stimulate platelet recruitment and adhesion to form a platelet plug[12,13]. Secondary haemostasis is a sequence of events, described as a coagulation cascade, that consequently converts soluble fibrinogen into insoluble fibrin. A fibrin mesh sticks to the platelet plug producing a haemostatic plug to seal the inside of wound[12,14].

At the beginning of the inflammatory phase, activated platelets also release pro-inflammatory cytokines and growth factors to stimulate the recruitment of immune cells to clean the wound area, initially involving infiltration of neutrophils and monocytes[15]. Monocytes undergo a phenotypic change to become macrophages. The previously constricted blood vessels also vasodilate because of increased prostaglandins, facilitating the chemotaxis of inflammatory cells[16,17]. The proliferation phase is charactered by re-epithelialization, capillary regeneration and the formation of granulation tissue(18). Fibroblasts and endothelial cells proliferate during this phase, stimulated by the numerous cytokines and growth factors released by the platelets and macrophages. This leads to the formation of new blood vessels in a process called angiogenesis[18].

After migration to the wound site, fibroblasts begin to proliferate and synthesize collagen and extracellular matrix components, such as proteoglycans, hyaluronic acid, glycosaminoglycans, and fibronectin, to form granulation tissue[1618]. The final stage is remodelling, which can last for several years. The formation of new capillaries slows, facilitating maturation of blood vessels in the wound. Type III collagen is replaced by type I collagen in the extracellular matrix to create a denser matrix with a higher tensile strength. The differentiation of fibroblasts into myofibroblasts causes the wound to physically contract. However, owing to differences in collagen type, new tissue after healing does not fully regain its original strength[1618].

Delayed wound healing can be caused by local and/or systemic factors. Local factors in the wound site include oxygen deficiency (causing chronic hypoxia), excessive exudate (causing maceration) or insufficient exudate (leading to desiccation), local infection, foreign bodies intensifying the inflammatory response, repetitive trauma, pressure/shear, and impaired vascular supply to the injury area[16,19].

Systemic factors that delay the healing process include the following[16,19]:

Oestrogen insufficiency, for instance in postmenopausal women, is known to impair all stages of wound repair process, especially inflammation and regranulation, with improved wound healing being a potential benefit of hormone replacement therapy. Androgens can repress cutaneous repair in both acute and chronic wounds, retarding the healing process and increasing inflammation[20].

The process can also be delayed in people with immunocompromised conditions, such as acquired immunodeficiency syndrome, cancer and malnutrition, with deficiencies in protein, carbohydrates, amino acids, vitamins A, C and E, zinc, iron, magnesium all having an effect[16,19,21]. Certain medicines can also delay the process, such as glucocorticoid steroids, chemotherapeutic drugs and non-steroidal anti-inflammatory drugs[19,21].

The most common causes of delayed chronic wound healing are infection and biofilm formation: biofilms are microscopically identifiable in up to 60% of chronic and recurrent wounds,leading to significant morbidity and mortality and an escalated healthcare cost[5,22,23].

A wound is considered infected when there are sufficiently large numbers of microbes presenting in wound environment or sufficient virulence to raise either a local or systemic immune response.

The wound-infection continuum has three stages: contamination, colonisation and infection. In the contamination phase, micro-organisms are unlikely to replicate because of an unfavourable environment. Colonisation happens when microbes successfully multiply, but not in sufficient levels to destroy host defences. However, the accelerated loads and persistence of microbes in wound environments may prolong the inflammatory phase and delay wound healing. When bacteria invade deeper into the wound bed and proliferate speedily, they can provoke an immune reaction and initiate local infection. As pathogens proliferate beyond the boundaries of the wound, infection may spread into deeper tissues, adjacent tissues, fascia, muscle or local organs. Eventually, systemic infection, such as sepsis, can occur when microbes invade into the body via vascular vessels or lymphatic systems, affecting the entirety of the body[24,25].

Biofilm is an extracellular polymeric substance produced by bacteria that acts as a physical barrier, enveloping bacteria and protecting them from host defences and antimicrobial agents. Several pathogens isolated from chronic wounds are typically capable of forming biofilms, such asStaphylococcus aureusandPseudomonas spp[5,23,24,26]. Biofilms persisting within chronic wounds can continuously stimulate host immunity, resulting in the prolonged release of nitric oxide, pro-inflammatory cytokines such as interleukin-1 and TNF-, and free radicals, and activation of immune complexes and complement, causing the healing process to fail and convert to a chronic state[23,27]. Sustained inflammatory reactions also trigger an escalated level of matrix metalloproteases, which can disrupt the extracellular matrix[16].

Most of the time, wound infection is diagnosed via visual inspection based on clinical signs and symptoms, including the classic signs of heat, pain, swelling, suppuration, erythema and fever. Typical characteristics of an acute infected wound are pain, erythema, swelling, purulent drainage, heat and malodour. In addition, a chronic wound may display signs of delayed healing, wound breakdown, friable granulation, epithelial bridging and pocketing in granulation tissue, increasing pain and serious odour.

Microbiological analysis of a specimen from wound cultures (using tissue biopsy or wound swab, pus collection or debrided viable tissue) is performed to identify causative microorganisms and guide the choice of antimicrobial therapy. Traditional diagnostics can be time consuming, and some organisms can be difficult to culture, so molecular techniques including DNA sequencing may help with characterising genetic markers[25]. Other laboratory markers, such as C-reactive protein, have also been used as markers and imaging techniques, such as CT scanning and autofluorescence imaging, may help with real-time diagnosis[25,28].

In clinical practice, the evaluation and identification of underlying conditions that affect wound healing are vital to optimising wound care. Accurate assessment of causes and comorbidities will inform the best course of treatment, such as compression therapy for venous leg ulcers or offloading (relief of pressure points) for people with diabetic foot ulcers[29]. The underlying pathologies of wounds are numerous and failure to address them can lead to a failure in healing[2,29].

Once any underlying conditions are identified, the wound bed should be prepared to optimise the chance of healing. A wound hygiene approach should be considered; its core principle is to remove or minimise unwanted materials, such as biofilm, devitalised tissue and foreign debris, from the wound bed to kickstart the healing process[30]. A holistic patient and wound assessment will ensure wound pathology and wound biofilm are managed simultaneously[30]. The TIME framework (tissue, infection/inflammation, moisture balance, edges) is a systematic approach to wound management[31]. Wound-bed preparation and the TIME approach should be used alongside a holistic assessment of other patient factors such as pain, nutrition and hydration[2].

Effective management of infection in chronic wounds involves the removal of necrotic tissue, debris and biofilms using debridement plus the appropriate use of antimicrobials (including topical antiseptics and systemic antibiotics)[1,32].

Antiseptics have a broad spectrum of bactericidal activity and are used externally for the purposes of eliminating bacterial colonisation, preventing infection, and potentially stimulating wound healing. They are less likely to cause antimicrobial resistance (AMR) than antibioticsand inhibit the development of microbes by disrupting cell walls and cytoplasmic membranes, denaturing proteins, and damaging bacterial DNA and RNA[5,23,33,34]. An ideal antiseptic agent should have broad-spectrum activity, a fast onset of action, long-lasting activity, be safe for healthy surrounding tissue, possess minimal allergenicity, be stable in blood and tissue protein, persistently remain within the wound bed, and potentially be active against biofilms[23,35]. Antiseptics, antimicrobial washes or surfactants can be used to clean the wound and peri-wound skin and prepare the wound bed for debridement[30].

A variety of antiseptic agents are used in clinical practice[23,34]:

Antiseptics can also be used as an adjunct to other therapies (e.g. negative pressure therapies) in treating complicated wound types(e.g.diabetic foot ulcers,venous leg ulcers and sternal wounds)[36].

All open wounds will be colonised with bacteria, but antibiotic therapy is only required for those that are clinically infected[37]. Systemic antibiotic therapy should only be considered for the treatment of cellulitis, osteomyelitis, sepsis, lymphangitis, abscess, and invasive tissue infection. Inappropriate use of systemic antibiotics may increase the risk of side effects and contributes to emergence of AMR[5]. The choice of initial therapy and the duration is frequently empirical and should take into account the type of wound, severity of infection, suspected pathogens and local AMR[38]. With severe infections, broad-spectrum antibiotics should be used against both gram-positive and gram-negative organisms, while a relatively narrow spectrum agent is enough for most mild and many moderate infections[5].

A systematic review assessed the clinical and cost-effective efficacy of systemic and topical antibiotic agents in the treatment of chronic skin wounds. The authors of the review suggested that there was insufficient evidence to support any routine use of systemic antibiotics in specific chronic wounds[39].

Appropriate and judicious use of antimicrobials must be considered when managing wounds. The use of topical antibiotics is not recommended for eliminating bacterial colonisation or wound infections because of their limited effectiveness, high risk of resistance and potential to cause contact allergy[5,35].

AMR occurs when microorganisms naturally evolve in ways that cause medicines used to treat infections to become ineffective, and these micro-organisms become resistant to most[40,41]. The misuse and overuse of antibiotics is a major cause of the emergence of AMR, via four main mechanisms[42]:

Moreover, the multicellular nature of biofilm matrix is likely to give extra protection to bacteria communities, makes them resistant to antibiotics. There are several proposed mechanisms for AMR related to biofilm: the alteration of chemical environment within biofilm, slow or inadequate diffusion of the antibiotics into the biofilm, and a differentiated biofilm subpopulation[43].

Topical antimicrobial use plays an important role when the wound is clinically infected or there is a suspected biofilm. The British Society for Antimicrobial Chemotherapy and European Wound Management Association position paper highlighted antimicrobial stewardship (AMS) a set of strategies to improve the appropriateness and minimise the adverse effects of antibiotic use as being central to wound care treatment to improving patient outcomes, reducing microbial resistance and decreasing the spread of infections caused by multidrug-resistant organisms[37]. Effective AMS avoids the use of antimicrobial therapy when not indicated while enabling the prescribing of appropriate antimicrobial interventions when they are indicated to treat infection.

The UK government has outlined a 20-year vision for reducing AMR, proposing a lower burden of infection through better treatment of resistant infections[44]. This includes the optimal use of antimicrobials and good stewardship across all sectors and appropriate use of new diagnostics, therapies, vaccines and interventions in use, combined with a full AMR research and development pipeline for antimicrobials, alternatives, diagnostics, vaccines and infection prevention across all sectors.

The use of alternatives to traditional antibiotic therapy is of huge interest for combating increasing AMR, including bacteriophage therapy, phage-encoded products, monoclonal antibodies and immunotherapy[45]. Among these, endolysins phage-encoded peptidoglycan hydrolases selectively targeting bacterial taxa have been identified as promising antimicrobial agents because of their ability to kill antimicrobial-resistant bacteria and lack of reported resistance However, challenges restrict the widespread use of endolysin therapy, such as limited drug-delivery methods, their specificity to particular bacteria types, and bioavailability via IV administration[46,47].

Debridement is the physical removal of biofilm, devitalisedtissue, debris and organic matter and is a crucial component of wound care. The presence of non-viable tissue in the wound bed prevents the formation of granulation tissue and delays the wound healing process. The removal of non-viable tissue encourages wound healing. The type of tissue found in the wound bed (e.g. whether necrotic or sloughy) will determine whether debridement is required. Factors such as bioburden, wound edges and the condition of peri-wound skin can also influence whether debridement is required[48]. A range of techniques can be used, dependent on the clinicians ability level: these include autolytic, larval, mechanical, sharp and surgical methods[49,50].

The concept of moist wound healing is not newand can lead to healing up to 23 times quicker than that of dry wound healing[51,52].Wound dressings such as cotton wool, gauze, plasters, bandages, tulle or lint should not be used, as they do not promote a moist wound healing environment, require excessive changes, and can cause skin damage and pain during dressing changes. They have therefore been replaced by newer types of wound dressingsthat can play a role in autolysis and debridement, maintain a relatively stable local temperature, keep the wound hydrated, promote wound repair and prevent bacterial infection[14,53,54].

Wound dressings should keep the wound free from infections, excessive slough, contaminants and poisons, keep the wound at the ideal temperature and optimum pH for healing, be permeable to water, but not microbes, come away from wound trauma during dressing changes, not be painful and be comfortable[55]. There are a variety of dressings available for managing chronic wounds, such as hydrogels, hydrocolloids, alginates, foams, and film dressings[56]. Dressings can also be used carriers for active agents including growth factors, antimicrobial agents, anti-inflammatory agents, monoterpenes, silver sulfadiazine or silver nanoparticles[57].

Potential factors that may influence dressing selection include:

Antimicrobial dressings impregnated with iodine, silver and honey are available[58]. They can be divided into two categories: those that release an antimicrobial into the wound and those that bind bacteria and remove them from the wound into the dressing. A more detailed overview can be found in a recent consensus document on wound care and dressing selection for pharmacists[57].

It is essential wound dressings do not inadvertently lead to moisture-associated skin damage an umbrella term encapsulating incontinence-associated dermatitis, intertriginous dermatitis (or intertrigo), peri-wound maceration and peristomal dermatitis. Practitioners should ensure the dressing can manage any exudate and protects the peri-wound area. Skin barriers can be used to protect the peri-wound area and prevent skin damage[59].

Widely used to aid the healing of acute, chronic and traumatic wounds, negative-pressure wound therapy (NPWT) removes interstitial fluid/oedema and excessive exudate, provides a moist environment, improves blood flow and tissue perfusion, and stimulates angiogenesis and granulation tissue formation[4,60]. Results from several studies have demonstrated the selective effect of NPWT in eliminating non-fermentative gram-negative bacilli in wounds[36]. Additionally, NPWT can be combined with additional topical antimicrobial solutions, reducing bacteria load, stimulating wound closure and decreasing wound size faster than conventional NPWT[36,61,62].

Hyperbaric oxygen therapy wasfirst proposed as an additional treatment for chronic wounds in the mid-1960s. Treatment involves the intermittent exposure of the body within a large chamber to 100% oxygen at a pressure between 2.0 and 2.5 atmosphere absolute, leading to an increase in oxygen levels within haemoglobin and elevating oxygen tissue tension at the wound site[63].A Cochrane reviewpublished in 2015 reported a significant improvement in the healing of diabetes ulcers in the short term when treated with hyperbaric oxygen therapy. However, further high-quality studies are needed before clinical benefits can be proven[64].

For chronic wound healing, electrical stimulation is the most frequently studied biophysical therapy[4]. It uses direct current, alternative current, and pulsed current. Electrical stimulation has been shown to benefit every stage of the wound-healing process, both at cellular and systemic levels. During the inflammation phase, electrical stimulation promotes vasodilation and increases the permeability of blood vessels, thereby facilitating cellular movement to the wound site and so promoting a shorter inflammatory response.

Studies have reported an inhibition in bacterial proliferation after electric stimulation. In the proliferation phase, electrical stimulation raises the migration, proliferation and differentiation of endothelial cells, keratinocytes, myofibroblasts and fibroblasts. At the systemic level, it promotes revascularisation, angiogenesis, collagen matrix organisation, wound contraction, and re-epithelialisation. Ultimately,electrical stimulation promotes the contractility of myofibroblast and converts type III collagen into type I, along with rearranging collagen fibres to optimise the scars tensile strength[8,65,66].

A prospective clinical study conducted across the UK suggested that using an externally applied electroceutical device, combined with compression bandaging and dressings, was a cost-effective treatment for venous leg ulcers, compared with conventional treatments[67].

Low-frequency ultrasound has been used as an adjunct treatment for chronic wounds. It has a debriding effect, removing debris and necrotic tissue (primarily via cavitational and acoustic streaming phenomena). Ultrasound is also reported to disrupt biofilmin vitro, thus increasing the sensitivity of bacteria to antimicrobials[68]. It is proposed to be effective instimulating collagen synthesis, increasing angiogenesis,diminishing the inflammatory phase as well as promoting cellular proliferation[69].Several clinical studies have shown a reduction in wound size when wounds are treated with low-frequency ultrasound therapy[7072].

Extracorporeal shock wave therapy (ESWT) has been proposed to aid wound healing by transmitting acoustic pulsed energy to tissues. ESWT seems to promote angiogenesis, stimulate circulation, reduce anti-inflammatory response, and upregulate cytokine and growth-factor reactions[4]. A clinical trial demonstrated the feasibility and tolerability of ESWT in wounds with different aetiologies[73]. Furthermore, a review concluded that ESWT brings more benefits for patients with diabetic foot ulcers than hyperbaric oxygen therapy, based on increased angiogenesis, tissue perfusion and cellular reactions with reduced cell apoptosis, as well as a higher ulcer healing rate[74].

More recent developments include introducing nanomedicine to wound-healing approaches. It has been used to achieve controlled delivery, stimulate chronic wound healing and control microbial infections[14,75]. Nanotechnology-based wound dressings like nanogels and nanofibers offer a larger surface area and greater porosity, potentially enhancing absorption of wound exudate. They can also facilitate collagen synthesis and ultimately re-epithelisation through supporting the migration and proliferation of fibroblasts and keratinocytes.

Nanomedicines also seem to aid healing through molecular and cellular pathways[75]. For example, a methacrylated gelatin (MeGel)/poly(L-lactic acid) hybrid nanofiber synthesised has been reported to stimulate the recruitment and proliferation of human dermal fibroblasts, thereby promoting wound healing[76]. Nanoparticles can not only act as carriers of antimicrobial agents, they can also have an intrinsic antimicrobial effect[75,77,78]. In 2021, Qiu et al. successfully developed an antibacterial photodynamic gold nanoparticle (AP-AuNPs) that demonstrated antibacterial effects on both Gram-negativeEscherichia coliand Gram-positiveStaphylococcus aureus,as well as potentially inhibiting biofilm formationin vitro[79].

Growth factors such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and fibroblast growth factor (FGF) are down-regulated in chronic wounds, suggesting that topical administration of growth factors and cytokines could improve wound healing[80].

Growth factors can improve wound repair through several mechanisms[81]:

Growth factors that have been studied in wound healing are EGF, VEGF, FGF, PDGF, transforming growth factor-beta 1 (TGF-1) and granulocyte-macrophage colony stimulating factor[82]. Becaplermin (rhPDGF-BB) was the first growth-factor therapy approved by the US Food and Drug Administration, after it demonstrated effectiveness in treating complex wounds when combined with standard wound care[80]. A systematic review and meta-analysis indicated that growth factors were effective in healing venous stasis ulcers, increasing wound healing by 48.8% compared with placebo and showing no difference in adverse effects compared with controls[83].

Stem cells may have certain advantages in wound healing because of their ability to differentiate into specialised cells and secrete numerous mediators including cytokines, chemokines, and growth factors[84,85]. This makes them a promising approach for treating chronic wounds.

Mesenchymal stem cells can be extracted from bone marrow, adipose tissue, umbilical cord blood, nerve tissue, or dermis and used both systemically and locally[86]. They release growth factors that stimulate blood-vessel and granulation tissue formation, fibroblast and keratinocyte migration, collagen synthesis, and fibroblast activation, increase re-epithelialisation, exert immunomodulatory properties, regulate inflammatory responses, and display antibacterial activities[85,8789].

Many studies have investigated the efficacy of stem-cell therapies for a variety of wounds, including burns, non-healing ulcers, and critical limb ischemia[9096]. A systematic review published in 2020 that investigated the clinical application of stem-cell therapy for the treatment of chronic wounds showed the potential of a variety of stem cells in the restoration of impaired wound healing, bothin vitroandin vivo, despite the clinical evidence being very limited. As the recorded studies were on case-by-case basis, there is a lack of comprehensive guidelines for the use of stem cells in different wounds[97].

Auto-transplantationof adipose tissue-derived mesenchymal stromal cells has been proposed as a safe, alternative method to treat chronic venous ulcers[96]. Bioscaffold matrices comprising hyaluronic acid, collagen or other bio-polymeric materials have increasingly been applied for stem-cell transplantation. These matrices not only provide wound coverage, but also offer protection for stem cells and controlled delivery[86].

Skin equivalents are polymeric biomaterials increasingly adopted for both acute and non-healing ulcers, such as venous ulcers, diabetic foot ulcers or pressure ulcers, to temporarily or permanently substitute the structure and function of human skin. Skin substitutes are designed to increase wound healing, provide a physical barrier that protects the wound from trauma or bacteria, provide a moist environment for the repair process, replace impaired skin components and decrease morbidity from more invasive treatments like skin grafting[98,99].

They can usually be classified as one of three major types: dermal replacement, epidermal replacement, and dermal/epidermal replacement[98]. Epidermal replacements (substitutes) comprising isolated autogeneous keratinocytes cultured on top of fibroblasts include Myskin (Regenerys), Laserskin(Fidia Advanced Biopolymers) and Epicel(Genzyme Tissue Repair Corporation). Dermal replacements include Dermagraft (Smith and Nephew) and Transcyte(Shire Regenerative Medicine)[98].

Epidermal/dermal skin replacements (also called composite skin substitutes) contain both epidermal and dermal layers that mimic the histological structure of original skin. The bi-layered bioengineering skin Apligraf (Organogenesis) was the first living skin equivalent for the management of complex chronic wounds like diabetic foot ulcers and venous leg ulcers. It is made up of a dermal layer of human fibroblasts embedded in a bovine type I collagen matrix and an epidermal layer generated by human keratinocytes[100]. Some other commercial products of composite substitutes are OrCel(Forticell Bioscience) andPermaDerm(Regenicin)[98]. In general, the current high cost of such dressings and limited evidence on effectiveness restricts them from being widely adopted[101]. Recently, technologies such as electrospinning or 3D-printing have been used to fabricate skin substitutes. Electrospinning can create nanofibers with high oxygen permeability, variable porosity, a large, exposed surface area and a morphology similar to the extracellular matrix, making them interesting candidates for skin substitutes[102,103].

TheNational Wound Care Strategy Programme, which was implemented by NHS England in 2018, has made progress in reducing unwanted variation in care and addressing suboptimal wound care.

Through its workstreams, the involvement of stakeholders, patients and carers, and the publication of the core capabilities for educating a multi-professional workforce, wound care has become a national priority. There are still many challenges in the management of chronic wounds the complexity of wound environment, limited knowledge of the biological, biochemical, and immunological healing processes, and the increasing complexity of disease pathophysiology that comes with ageing populations.

The development of standardised and clinically relevant testing for wound dressings, along with high-quality clinical trials, would enable useful comparisons of treatments. The whole episode of care should be considered in assessments of the cost-effectiveness of different dressings and devices, rather the simple cost of the individual entity. All these complex concerns restrict success in wound management, which in turn negatively impacts the quality of life of the patients and places a burden on global healthcare systems[75,104]. Organisations and healthcare providers should share best practice and education of healthcare professionals is needed to get the best outcomes for patients with preventable chronic wounds.

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Bhagavan N, Ha C-E. Biochemistry of hemostasis. In: Essentials of Medical Biochemistry . Academic Press 2015. 752.

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Pratt J, West G. Pressure therapy: history and rationale. In: Pressure garments: A manual on their design and fabrication. ButterworthHeinemann 1995. 146.

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Current and advanced therapies for chronic wound infection - The Pharmaceutical Journal

Introduction

Stem cells are highly specialized cell types with an impressive ability to self-renew, able to transform into one or even more specific cell types that play a significant role in the regulation and tissue healing process.17 To self-renew, a stem divides into two identical daughter stem cells and a progenitor cell and the embryonic and adult cells contain stem cells.1,2,8

Curing patients with serious medical conditions has been the focus of all disciplines of medical research for many years. Stem cell treatment has evolved into a highly exciting and progressed field of scientific research. Major advances have recently been introduced in fundamental and translational stem-cell-based treatment studies. As stem cell research progressed, many therapeutic options were investigated. The development of therapeutic procedures has sparked a great deal of interest.1,9 Humanity has known for many years that it is possible to regenerate lost tissue. Recently, the regenerative medicine research has taken hold, defying the tremendous scientific advances in the molecular biology sciences only. Technological advances provide limitless opportunities for transformational and potentially restorative therapies for many of humanitys most illnesses. A variety of human organs have successfully yielded stem cells. Besides this, the cell therapy is rapidly bringing good advancements in the healthcare system, intending to restore and possibly replace injured tissue, as well as organs, and ultimately restore the functional capacity of the body.2,10,11

The stem cells can be obtained from various sources of Adult (Adult body tissues), Embryonic (Embryos), Mesenchyma (Connective tissue or stroma), and Induced pluripotent stem [ips] cells (Skin cells or tissue-specific cells).3,68,1215

Due to various stem cells cellular characteristics, the therapeutic clinical possibilities of stem-cell-based treatment are considered promising. These cells can regrow and restore various types of body tissues, for this reason, they are recognized as precursor cells to all kinds of cells.15 The following are the distinguishing features: 1. Self-renewal- Divide without distinction to generate an infinite supply, 2. Multi-potency- One mature cell may distinguish more than one, 3. Pluripotency- Create all sorts of cells except for embryonic membrane cells, 4. Toti- potency- Produce various sorts of cells, including embryonic stem cells.1,2,6,7,16

Stem cells are essential human cells that really can self-renew and make a distinction into particular mature cell types.3,6 The different types of stem cells are embryonic, induced pluripotent, and adult kind of cell types. They all share the important feature of self-renewal, and the ability to discern themselves. It should be mentioned that, the stem cells are not homogeneous, but instead appear in a progressive order. Totipotent stem cells are the most basic and immature stem cells. The above cells can form a complete embryo and also extra-embryonic tissue. This one-of-a-kind efficiency is only present for a short period, starting with ovum development and completing whenever the embryo achieves the 4 to 8 cell phases. Having followed that, cells that divide until they approach the blastocyst, about which point they end up losing their totipotency and acquire a pluripotent character trait, at which cells can only distinguish through each embryonic germ stack. After a few divisions, the pluripotency character trait starts to fade and the distinguishing ability has become more lineage constrained, where its cells are becoming multipotent, indicating they could only transform into the cells connected to a cell or tissue of origin.10 Many researchers believe that adult stem cells should be used in stem cell therapies.6,17

The stem cells can be transformed into a wide range of specialized functional cell types.3,18 In response to injury or maturation, those same stem cells can propagate in massive quantities.19 Adult, embryonic, and induced pluripotent stem cells are examples of stem cell-based therapies.14,15,1921 The stem cells, due to their capability to distinguish the specific cell types requisite for a diseased tissue regeneration, can provide an effective solution, while tissue and organ transplantation are considered necessary.10 The sophistication of stem cell-based treatment interventions, on the other hand, probably leads researchers to seek stable, credible, and readily available stem cell sources capable of converting into numerous lineages. As an outcome, it is critical to exercise caution when selecting the type of stem cells to be used in therapeutic trials.12,14,22

Only with the explosive growth of basic stem cell research in recent years, the comparatively recent study sector of Translational Research had also grown exponentially, starting to build on major research knowledge and insight to advance new therapies. Once the necessary regulatory clearances have been obtained, the clinical translation process can start. Translational research is important because it acts as a filtration system, ensuring that only safe and effective therapeutic approaches start making it to the clinic.23 Recent research illustrating, the successful application of stem cell transplantation to patient populations suggests that, such restorative approaches have been used to address a wide variety of complicated ailments of future concerns.19,24

Currently, clinical trials are available for a variety of stem cell-based treatments based on adult stem cells. To date, the WHO International Clinical Experiments Registration process has recorded more than 3000 experiments involved based on adult stem cells. Furthermore, preliminary trials involving novel and intriguing pluripotent stem cell therapies have been registered. These studies findings will assist the ability to comprehend and the timeframes required to obtain effective treatments and it will contribute to a better knowledge of the different disorders or abnormalities.10

The role of stem cells in modern medicine is vital, both for their widespread application in basic research and for the opportunities they provide for developing new therapeutic strategies in clinical practice.6,16 In recent times, the number of studies involving stem cells has expanded tremendously. Globally, thousands of studies claiming to use stem cells in experimental therapies have now been in the investigation field. This may give the impression that such treatments have already been shown to be extremely effective in the context of healthcare. Despite some promising results, the vast majority of stem cell-based therapeutic applications are still in the experimental stage itself.6,25

The stem cells are a valuable resource for understanding organogenesis as well as the bodys continual regenerative capacity. These cells have brought up enormous anticipations among doctors, investigators, patients, and the public at large because of their ability to distinguish into a variety of cell types.25 These cells are necessary for living beings for a variety of reasons and can play a distinguishable role. Several stem cells can play all cell types roles, and when stimulated effectively, they can also repair damaged tissue. This capability has the potential to save lives as well as treat human injuries and tissue destruction. Moreover, different kinds of stem cells could be used for several purposes, including tissue formation, cell deficiency therapeutic interventions, and stem cell donation or retrieval.3,6,26

New research demonstrating that the successful application of stem cell treatments to patients has expressed hope that such regenerative strategies might very well one day is being used to address a wide variety of problematic ailments. Furthermore, clinical trials incorporating stem cell-based therapeutics have advanced at an alarming rate in recent years. Some of these studies had a significant impact on a wide range of medical conditions.10 As a regenerative medicine strategy, cell-based treatment is widely regarded as the most fascinating field of study in advanced science and medicine. Such technological innovation paves the way for an infinite number of transformational and potentially curable solutions to some of humanitys most pressing survival issues. Moreover, it is gradually becoming the next major concern in medical services.11

Modern data, which shows that the successful stem cell transplantation in beneficiaries has raised hopes on the certain rejuvenating approaches, will one day be used to treat many different types of challenging chronic conditions.24 Preliminary data from highly innovative investigations have documented that the prospective advancement of stem cells provides a wide range of life-threatening ailments that have so far eluded current medical therapy.2,10,11 Furthermore, clinical trials involving stem cell-based therapies have advanced at an unprecedented rate. Many of these studies had a significant impact on various disorders.19 Despite the increasing significance of articles concerning viable stem cell-based treatments, the vast majority of clinical experiments have still yet to receive full authorization for stem cell treatments confirmation.11,12,27

Even though the first case of AIDS were noted nearly 27 years ago, and the etiologic agent was noticed 25 years ago, still for the effective control of the AIDS pandemic continues to remain elusive.28 The HIV epidemic started in 1981 when a new virus syndrome defined by a weakened immune system was revealed in human populations across the globe. AIDS showed up to have a substantial reduction in CD4+ cell counts and also elevated B-cell multiplication.15,2831

The agent that causes AIDS, later named HIV, is a retroviral disease with a genomic structural system made up of 2 identical single-stranded RNA particles.3234 According to the Centres for Disease Control and Prevention, with over 1.1 million Americans are presently infected with the virus.31 Compromised immune processes in HIV and AIDS, as well as partial immune restoration, barriers are confirmed for HIV disease eradication. Innovative developmental strategies are essential to maximizing virus protection and enabling the host immune response to eliminate the virus.35

The progression of HIV infection in humans is divided into the following stages of acute infection, chronic infection, and AIDS.15,36 During the acute infection phase, the circulation has a high viral replication, is extremely infectious, that may or may not demonstrate flu-like clinical signs. In the chronic stage, the viral load is lesser than in the acute stage, and individuals are still infectious but may be symptomless. The patient has come to the end stage of AIDS whenever the CD4+ cell count begins to fall below 200 cells/mm or even when opportunistic infections are advanced.15,36

There are currently two types of HIV isolated HIV-1 and HIV-2.15,37,38 However, HIV-1 is the most common cause of AIDS throughout the world, while HIV-2 is only found in a few areas of an African country. Although both virions can cause AIDS, HIV-2 infection is much more likely to occur in central nervous system disorder.15 Besides this, HIV-2 seems to be less infectious than HIV-1, and HIV-2 infection induces AIDS to develop more slowly. Even though both HIV-1 and HIV-2 have a comparable genetic structure comprised of group-specific antigen, polymerase, and envelope genes, their genome organizational structures are differed.15,3739

HIV infiltrates immune cell types, CD4+ T cell types, and monocytes, resulting in a drop in T-cell counts below a critical level and the failure of cell-mediated immune function.15,40 The glycoprotein (gp120) observed in the virion envelope comes into contact with the CD4 particle with high affinity, allowing HIV to infect T cells. By interacting with their co-receptors, CXCR4 and CCR5, the virus infiltrates T cells and monocytes. The retrovirus uses reverse transcriptase to convert its RNA into DNA after attaching it to and entering the host cell. These newly replicated DNA copies then exit the host cell and infect other cells.15,40,41

HIV-1 is a retrovirus and belongs to a subset of retroviruses known as lentiviruses.38,42 Infection is the most common global health concern around the world.15 It has destroyed the millions of peoples health and continues to wreak havoc on the individual health of millions more. The pandemic of HIV-1 is the most devastating plague in the history of humans, as well as a significant challenge in the areas of medicine, public health, and biological science of research activities.34,43 Antiretroviral therapy is the only treatment that is commonly used. This is not a curative treatment; it must be used for the rest of ones life.15 Although antiretroviral therapy has reduced significantly HIV intensity and transmission, the virus has not been eradicated, and its continued presence can lead to additional health issues.44

Infection with the human immunodeficiency virus necessitates entry into target cells, such as through adhesion of the viral envelope to CD4 receptor sites.43 Cellular antiviral responses fail to eliminate the virus, resulting in a gradual depletion of CD4+ T cells and, finally, a severely compromised immune functioning system. Unfortunately, there is no cure for the virus that destroys immunity.4447 In advanced HIV infection, memory T-cell depletion primarily affects cellular and adaptive immune responses, with a minor impact on innate immune responses.48 Globally, 37.7 million people were living with HIV in 2020, and with 1.5 million individuals are infected with the virus.49 The advancement of stem cell therapy and the conduct of implemented clinical trials have revealed that stem cell treatment has high hopes for a range of medical conditions and implementations.15

Stem cell treatment has shown impressive outcomes in HIV management and has the potential to have significant implications for HIV treatment and prevention in the future. In HIV patients, stem cell therapy helps to suppress the viral load even while enabling antiretroviral regimens to be tapered. Interestingly, this practice led to a significant improvement in procedure outcomes soon after starting antiretroviral treatment.15 Stem cell transplantation can alleviate a wide variety of diseases that are currently incurable. They could also be used to create a novel anti-infection therapy strategic plan and to enhance the treatment of immunologic conditions such as HIV infection. HIV wreaks havoc on immune system cells.30,50

The virus infects and replicates within T-helper cells (T-cells), which are white immune system cells. T-cells are also referred to as CD4 cells. HIV weakens a persons immune system over time by pulverizing more CD4 cells and multiplying itself. More pertinently, if the individual has been unable to obtain anti-retroviral medicine, he will progressively fail to control the infectious disease and illnesses.3,15,42

Despite 36 years of scientific research, investigators are still trying to cure human HIV and its potential problem, AIDS.3,5153 HIV continues to face unconquerable dangers to human survival. This virus has developed the potential to avoid anti-retroviral therapy and tends to result in victim death.52 Investigators are still looking for effective and all-encompassing treatment for HIV and its complexity, AIDS.54 This massive amount of data revealed potential AIDS treatment targets.55 Thousands of research projects have yielded a great deal of information on the elusive AIDS life cycle to date.5456 These massive amounts of data supplied possible targets for AIDS treatment.33,55,56 In HIV-infected patients, using stem cell therapy can augment the process of keeping the viral load stagnant by permitting antiretroviral regimens to be tapered.15

Overall, stem cell-based strategies for HIV and AIDS treatment have recently emerged and have become a key area of research. Ideally, effective stem cell-based therapeutic approaches might have several benefits.30 Clinical studies encompassing stem cell therapy have shown substantial therapeutic effects in the treatment of various autoimmune, degenerative, and genetic problems.15,25 Substantial progress has been developed in the treatment of HIV infection using stem cell-based techniques.30

Successfully treated, clinical studies have shown that total tissue recovery is feasible.15,57 In the early 1980s, the first stem cell transplants were accomplished on HIV-positive patients who were unsure of their viral disease. Following the above preliminary aspects, many HIV-positive patients with concurrent malignant tumours or other hematologic disorders underwent allogeneic stem cell transplantation around the world.42 After ART became a common treatment option for patients,58,59 the procedures prognosis improved dramatically. In addition, a retrospective study of 111 HIV+ transplant patients demonstrated a mildly lower overall survivorship performance in comparison to an HIV-uninfected comparison group.60

Earlier, the primary problem for people living with HIV and AIDS was immunodeficiency caused by a loss of productive T-cells. Some clinicians intended to replenish lost lymphocytes through adoptive cell transplants in the initial days before efficacious antiretroviral therapy options were available. Immunologically, it is relatively simple in an isogeneic condition, as illustrated on HIV-positive individuals with just a correlating identical twin who received T-lymphocytes and stem cell transfusions to rebuild the weak immune status of the patient.60 Cell therapy transfusion may be used to remove resting virion genomes from CD4+ immune cells and macrophages mostly through genome-editing or cytotoxic anti-viral cells.15,60 Cell technology and stem cell biological reprogramming developments have made a significant contribution to novel strategies that may give confidence to HIV healing process.3 However, human embryonic stem cells can be distinguished into significant HIV target cells, according to several research findings.30,61,62

Initially, stem cell transplantation was believed to influence the clinical significance of HIV infection, but viral regulation was not accomplished in the discipline. Moreover, improvements in stem cell transplants utilizing synthetic or natural resistant cell resources, in combination with novel genetic manipulative tactics or the advancement of cytotoxic anti-HIV effector cells, have significantly accelerated this sector of HIV cell management.60 Multiple techniques are being introduced to overcome HIV, either through protecting cells from infectious disease or by continuing to increase immune responses to the viral infection.30 The various methods are as follows: Bone marrow stem cells Therapies, Autologous stem cell transplantations, Hematopoietic stem cell transplantation, Genetical modifications of Hematopoietic stem cells (HSCT), HSCT and HAART therapeutic approach, Human umbilical cord mesenchymal stem cell transplantation, Mesenchymal stem/stromal cells (MSCs) applications, CCR5 Delta32/Delta32 Stem-Cell Transplantation, CRISPR and stem cell applications, Induced Pluripotent Stem Cells applications.

According to the findings, circulating replicative HIV remains the most significant threat to effective AIDS therapy. As a result, a method for conferring resistance to circulating HIV particles is required. The effective viral burden in the human body would be significantly reduced if it were possible to defeat reproducing HIV particles.43,44 For the treatment of AIDS, a restorative approach that relies on bone marrow stem cells has been suggested.52 The proposed treatment method captures and eventually destroys circulating HIVs using receptor-integrated red blood cells. Red blood cell membranes can be equipped with the CD4 receptor and the C-C chemokine receptor type 5 and C-X-C chemokine receptor type 4 co-receptors, which will selectively bind circulating HIV particles.15,30,32,33,43,44,46,6365

The term autologous pertains to blood-forming stem cells obtained from the patient for use as a source of fresh blood cells followed by high-dose chemotherapeutic agents.66 Lymphoma is still the biggest cause of mortality in HIV patients. Autologous stem cell recovery or transplantation with high-dose treatments has long been supported as a treatment for certain types of cancer in HIV-negative patients, including leukaemia and lymphoma. Individuals over the age of 65, as well as those with health problems such as HIV, were excluded from initial transfusion experiments. Moreover, the treatment regimen mortality of transplantation has also been reduced significantly due to its use of peripheral blood stem cells rather than bone marrow and the use of newer marginal conditioning therapeutic strategies. HIV-infected clients may be able to utilize enough stem cells for an autologous transplant advancement in HIV management. High-dose Autologous stem cell transplant (ASCT) treatments are better than conventional treatment in people with relapsed non-Hodgkin lymphoma, according to randomized trial evidence. Similarly, studies on HIV-negative people with Hodgkin Lymphoma have shown that ASCT would provide patients with repetitive illness with long-term progression-free survival.66,67 Even so, the clinical trial on Allogeneic Hematopoietic Cell Transplant for HIV Patients with Hematologic Malignancies report was explained as, the cell-associated HIV DNA and inducible infectious virus were not detectable in the blood of patients who attained complete chimerism.68

The study on long-term multilineage engraftment of autologous genome-edited hematopoietic stem cells in nonhuman primates report findings was Genome editing in hematopoietic stem and progenitor cells (HSPCs) is a potential innovative approach for the treatment of numerous human disorders. This report shows that genome-edited HSPCs engraft and contribute to multilineage repopulation following autologous transplantation in a clinically relevant large animal model, which is an important step toward developing stem cell-based genome-editing therapeutics for HIV and possibly other illnesses.69

Research on comprehensive virologic and immune interpretation in an HIV-infected participant again just after allogeneic transfusion and analytical interruption of antiretroviral treatment findings are the instance of HIV-1 cure having followed allogeneic stem cell transplantation (allo-SCT), resulting allo-SCTs in HIV-1 positive participants have failed to cure the disease. It describes adjustments in the HIV reservoir in a single chronically HIV-infected client who had undergone allo-SCT for acute lymphoblastic leukaemia treatment and was obtaining suppressive antiretroviral treatment.

To estimate the size of the HIV-1 reservoir and describe viral phylogenetic and phenotypic modifications in immune cells, the investigators just used leukapheresis to obtain peripheral blood mononuclear cells (PBMCs) from a 55-year-old man with chronic HIV infection prior and after allo-SCT. Once HIV-1 was found to be unrecognizable by numerous tests, including the PCR measurement techniques both of overall and fully integrated HIV-1 DNA, recompilation virus precise measurement by significant cell input quantifiable viral outgrowth assay, and in situ hybridization of intestine tissue, the client accepted to an analytic treatment interruption (ATI) with recurrent clinical observing on day 784 post-transplantation. He continued to remain aviremic off ART until ATI day 288, once a reduced virus rebound of 60 HIV-1 copies/mL resulted, which expanded to 1640 HIV-1 copies/mL five days later, urging ART reinitiation. Rebounding serum HIV-1 action sequences were phylogenetically distinguishable from pro-viral HIV-1 DNA discovered in circulating PBMCs before transplantation. It was indicated that allo-SCT tends to result in significant reductions in the magnitude of the HIV-1 reservoir and a >9-month ART-free cessation from HIV-1 multiplication.34

The Impact of HIV Infection on Transplant Outcomes after Autologous Peripheral Blood Stem Cell Transplantation: A Retrospective Study of Japanese Registry Data reported as ASCT is a successful treatment option for HIV-positive patients with non-Hodgkin lymphoma and multiple myeloma (MM). HIV infection was associated with an increased risk of overall mortality and relapse after ASCT for NHL in a study population.70

The procedure of delivering hematopoietic stem cells mostly through intravenous infusion to restore normal haematopoiesis or treat cancer is known as hematopoietic stem cell transplantation.71 There has recently been a rise in the desire to develop strategies for treating HIV/AIDS diseases employing human hematopoietic stem cells,30 along with this Hutter and Zaia were evaluated the background of Haematopoietic stem cell transplantation (HSCT) in HIV-infected individuals.42

Attempts to use HSCT as a technique for immunologic restoration in AIDS patients or as a therapeutic intervention for malignant tumours were initially insufficient. Regretfully, in the absence of sufficient ART, HSCT seemed to have no impact on the evolution of HIV infection, and the majority of the patients ended up dead of rapidly deteriorating immunosuppression or reoccurring lymphoma or leukaemia. A specific instance report described how an un-associated, matched donor supplied allogeneic HSCT to a patient with refractory lymphoma. The virus was unrecognizable by isolating or PCR of peripheral blood mononuclear cells commencing on day 32 after transplantation. Although HIV-1 was unrecognizable by cultural environment or PCR of several tissues examined at mortem, the patient died of recurring lymphoma on day 47. Another client who obtained both allogeneic HSCT and zidovudine had similar results, with HIV-1 becoming unnoticeable in the blood by PCR analysis. In some other particular instances, a 25-year-old woman with AIDS who obtained an allogeneic HSCT from a corresponding, unfamiliar donor after controlling with busulfan and cyclophosphamide and ART with zidovudine and IFN-2 regimen continued to live for 10 months before falling victim to adult respiratory distress. However, PCR testing of autopsy tissues revealed that they were HIV-1 negative.72

Recent research discovered significant progress towards the clinical application of stem cell-based HIV therapeutic interventions, principally illustrating the opportunity to effectively undertake a large-scale phase two HSC-based gene therapy experiment. In this investigation, the research team used autologous adult HSCs that had been transduced to a retroviral vector that usually contains a tat-vpr-specific anti-HIV ribozyme to develop cells that were less vulnerable to productive infection,73 whereas vector-containing cells have been discovered for extended periods (more than 100 weeks in most people) and CD4+ T cell gets counted were significantly high within anti-HIV ribozyme treating people group compared with the placebo group, the impacts on viral loads were minimal. The studys success, even so, is based on the realization that a stem cell-based strategy like this is being used as a more conventional and efficacious therapeutic approach.30 Some other latest clinical studies used a multi-pronged RNA-based strategic plan which included a CCR5-targeted ribozyme, an shRNA targeting tat/rev transcripts, and a TAR segment decoy.74

These crucial research findings are explained on lentiviral-based gene therapy vectors that can genetically manipulate both dividing and non-dividing HSCs and are less likely to cause cellular changes than murine retro-viral-based vectors. Long-term engraftment and multipotential haematopoiesis have been demonstrated in vector-containing and expressing cells, according to the researchers. Whereas the antiviral effectiveness was not reviewed, the results demonstrate the strategys protection, which helps to expand well for the possibility of a lentiviral-based approach in the upcoming years.30

A further approach, with a different emphasis, has been started up in the hopes of trying to direct immune function to target specific HIV to overcome barriers to attempting to clear the virus from the patient's body. These strategies use gene treatment innovations on peripheral blood cells to biologically modify cells so that they assert a receptor or chimeric particle that enables them to especially target a specific viral antigen,75 deception of HIV-infected peoples peripheral blood T cells raises issues to be addressed, such as the effects of ongoing HIV infection and ex vivo modification on the capabilities and lifetime of peripheral blood cells. Further to that, the above genetically manipulated cells would demonstrate their endogenous T cell receptors, and the representation of the newly introduced receptor could outcome in cross-receptor pairing, resulting in self-reactive T cells. Most of these deficiencies could be countered by enabling specific developmental strategies to take place that can start generating huge numbers of HIV-specific cells in a renewable, consistent way that can restore defective natural immune activity against HIV.30

One strategy being recognized is the application of B cells obtained from HSCs to demonstrate anti-HIV neutralizing specific antibodies. While animal studies have shown that neutralizing antibodies could protect against infection, and extensively neutralizing antibodies have been noticed in some HIV-infected persons, safety from a single engineered antibody might be exceptional.76,77 Realizing antibody binding and virus neutralization may assist in the development of chimeric receptors or single-chain therapeutic antibodies with recognition domains for other techniques that identify cellular immunity against HIV-infected cells.78,79 Thereby, genetically modifying HSCs to generate B cells that produce neutralizing anti-HIV specific antibodies, or engineering HSCs to enable multipotential haematopoiesis of cells that express a chimeric cellular receptor usually contains an antibody recognition domain, indicate one arm of an HSC-based engineered immunity process.30

A further technique of using HSCs that were genetically altered with molecularly cloned T-cell receptors or chimeric molecules particular to HIV to yield antigen-specific T cells. The basic difference in this strategy is that the cells produced from HSCs after standard advancement in the bone marrow and thymus are made subject to normal central tolerance modalities and are antigen-specific naive cells, and therefore do not have the ex-vivo manipulation and impaired functioning or exhaustion problems that other external cell modification methods would have. In this context, the latest actual evidence research using a molecularly cloned T cell receptor particular to an HIV-1 Gag epitope in the aspect of HLA-A*0201 revealed that HSC altered in this ability can progress into fully functioning, mature HIV specialized CD8+ T cells in human thymic tissue that conveys the acceptable constrained HLA-A*0201 particles.80 This explores the possibility of genetically engineering HSCs with a molecularly cloned receptor and signifies a step toward a better understanding and application of initiated T cell responses, which would probably result in the eradication of HIV infection from the body, similar to the natural immune function of other virus infections and pathogenic organisms.30

In an allogeneic transplantation, donor stem cells replace the patients cells.66 Allogeneic hematopoietic stem cell transplantation (HSCT) has appeared as one of the most potent treatment possibilities for many people who suffer from hemopoietic system carcinomas and non-malignant ailments.81 Both HIV-cured people have received HSCT utilizing CCR5 132 donor cells.82,83 This implies that HIV eradication necessitates a decrease in the viral reservoir through the myeloablative procedures,8486 Having followed that, immune rebuilding with HIV-resistant cells was carried out to prevent re-infection.45 The possibility of adoptive transfer of ex vivo-grown, virus-specific T-cells to prevent and control infectious diseases (eg, Cytomegalovirus and EBV) in immunocompromised patients helps to make adoptive T-cell treatment a feasible strategy to inhibit HIV rebound having followed HSCT.81,87,88

The Engineered Zinc Finger Protein Targeting 2LTR Inhibits HIV Integration in Hematopoietic Stem and Progenitor Cell-Derived Macrophages: In Vitro Study, the researchers investigated the efficacy and safety of 2LTRZFP in human CD34+ HSPCs. Researchers used a lentiviral vector to transduce 2LTRZFP with the mCherry tag (2LTRZFPmCherry) into human CD34+ HSPCs. The study findings suggest that the anti-HIV-1 integrase scaffold is an enticing antiviral molecule that could be utilised in human CD34+ HSPC-based gene therapy for AIDS patients.89

The fundamental element of HIV management is stem cell genetic modification, which involves genetically enhanced patient-derived stem cells to overcome HIV infection. In this sector, numerous experimental studies, in vitro as well as in vivo examinations, and positive outcomes for AIDS patients have been conducted.65,74 Genetic engineering for HIV-infected individuals can provide a once-only intervention that minimizes viral load, restores the immune system, and minimizes the accumulated toxicities concerned with highly active antiretroviral therapy (HAART).73 HSCs can be genetically altered, permitting for the addition of exogenous components to the progeny that protects them from direct infectious disease and/or enables them to target a specific antigen. Besides that, HSC-based strategies can enhance multilineage hemopoietic advancement by re-establishing several arms of the immune function. Eventually, as HSCs can be produced autologously, immunologic tolerance is typically high, enabling effective engraftment and subsequent distinction into the fully functioning mature hematopoietic cells.30

The utilization of human HSCs to rebuild the immune function in HIV disease is one application that tries to preserve newly formed cells from HIV infection, while another attempts to develop immune cells that attack HIV infected cells. While each initiative has many different aspects at the moment, they represent huge attention to HIV/AIDS therapies that, most likely when integrated with the other therapeutic approaches, would result in the body trying to overcome the obstacles needed for the virus to be effectively cleaned up.30

While HSC transplantation technique and processes are not accurately novel, as they are commonly and effectively used to address a wide variety of haematological diseases and malignant neoplasms,90 trying to combine them with a gene therapeutic strategy represents a unique and possibly potent therapeutic approach for HIV and AIDS-related ailments. As the results of HIV-infected patients who obtained autologous HSCT continued to improve, there was growing interest in genetically altered stem cells that were tolerant to HIV disease. Multiple logistical challenges have impeded the advancement of genetically modified hematopoietic stem cells as a conceivable therapeutic option for HIV/AIDS.72,73

UCLAs Eli and Edythe Broad Center for Restorative Medicine and Stem Cell Studies is one bit closer to constructing an instrument to arm the bodys immune system to attack and defeat HIV. Dr. Kitchen et al are the first ones to disclose the use of a chimeric antigen receptor (CAR), a genetically manipulated molecule, in blood-forming stem cells. In the experiment, the research team introduced a CAR gene into blood-forming stem cells, which were then moved into HIV-infected mice that had been genetically programmed. The scientists found that CAR-carrying blood stem cells efficiently transformed into fully functioning T cells that have the ability to kill HIV-infected cells in mice. The outcome was an 80-to-95 percentage reduction in HIV levels, suggesting that stem-cell-based genetic engineering with a CAR might be a viable and effective approach for treating HIV infection among humans. The CAR initiative, according to Dr. Kitchen, is much more able to adapt and ultimately more efficient, which can conceivably be used by others. If any further experiment showcases keep promising, the scientists expect that a practice based on their strategy will be accessible for clinical development within the next 510 years.91

HSCT and HAART therapeutic approaches in treating HIV/AIDS as the emergence of highly active antiretroviral therapy (HAART) in the 1990s improved survival rates of HIV infection, leading to a major dramatic drop in the occurrence of AIDS and AIDS-related mortalities. As an outcome, there is much less involvement with using HSCT as a therapy for HIV infection.28,33,43,67,86

A randomized clinical trial of human umbilical cord mesenchymal stem cell transplant among HIV/AIDS immunological non responders investigation, the researchers examined the clinical efficacy of transfusion of human umbilical cord mesenchymal stem cells (hUC-MSC) for immunological non-responder clients with long-term HIV disease who have an unmet medical need in the aspect of effective antiretroviral therapy. From May 2013 to March 2016, 72 HIV-infected participants were admitted in this stage of the randomized, double-blind, multi-center, placebo-controlled dose-determination investigation. They were either given a high dose of hUC-MSC of 1.5106/kg body weight as well as small doses of hUC-MSC of 0.5106/kg body weight, or a placebo application. During the 96-week follow-up experiment, interventional and immunological character traits were analysed. They found that hUC-MSC therapy was both safe and efficacious among humans. There was a significant rise in CD4+ T counts after 48 weeks of treatment in both the high-dose (P 0.001) and low-dose (P 0.001) groups, but no changes in the comparison group.92

One interesting invention made by a team of UC Davis investigators is the recognition of a particular form of stem cell that can minimize the quantity of the virus that tends to cause AIDS, thus dramatically increasing the bodys antiviral immune activity. Mesenchymal stem/stromal cells (MSCs) furnish an incredible opportunity for a creative and innovative, multi-pronged HIV cure strategic plan by augmenting prevailing HIV potential treatments. Even while no antivirals have been used, MSCs have been able to increase the hosts antiviral responses. MSC therapeutic approaches require specialized delivery systems and good cell quality regulation. The studys findings lay the proper scientific foundation for future research into MSC in the ongoing treatment of HIV and other contagious diseases in the clinical organization.35

Infection with HIV-1 necessitates the existence of both specific receptors and a chemokine receptor, particularly chemokine receptor 5 (CCR5).46 Resistance to HIV-1 infection is attained by homozygozygozity for a 32-bp removal in the CCR5 allele.93 In this investigation, stem cells were transplanted in a patient with severe myeloid leukaemia and HIV-1 infection from a donor who was homozygous to Chemokine receptor 5 delta 32. The client seemed to have no viral relapses after 20 months of transplantation and attempting to stop antiretroviral medicine. This finding highlights the essential role that CCR5 tries to play in HIV-1 infection maintenance.86

In comparison, additional HIV-1-infected people who have received allogeneic stem cell transplants with cells from CCR5 truly wild donors did not have long-term relapses from HIV-1 rebound, with 2 of these patients trying to report viral reoccurrence 12 as well as 32 weeks after analytic treatment interruption, respectively. Among these 2 patients, allogeneic stem cell transplantation probably reduced but did not eliminate latently HIV-infected cells, enabling persistent viral reservoirs to activate viral rebound. This viewpoint may not rule out the potential that allogeneic hematopoietic stem cell transplantation might result in a much more comprehensive or near-complete elimination of viral reservoirs, enabling long-term drug-free relapse of HIV-1 infection in some contexts.84 As just one report demonstrated a decade earlier, a curative treatment for HIV-1 remained elusive. The Berlin Patient has undergone 2 allogeneic hematopoietic stem cell transplantations to cure his acute myeloid leukaemia utilizing a potential donor with a homozygous genetic mutation in HIV coreceptor CCR5 (CCR532/32).15,34,46,64,65,72,82,84,86,9496 Other similar studies with CCR5 receptor targets are as follows: Automated production of CCR5-negative CD4+-T cells in a GMP compatible, clinical scale for treatment of HIV-positive patients,97 Mechanistic Models Predict Efficacy of CCR5-Deficient Stem Cell Transplants in HIV Patient Populations,98 Conditional suicidal gene with CCR5 knockout.99

Clustered regularly interspaced short palindromic repeats CRISPR/Cas9 is a promising gene editing approach that can edit genes for gain-of-function or loss-of-function mutations in order to address genetic abnormalities. Despite the fact that other gene editing techniques exist, CRISPR/Cas9 is the most reliable and efficient proven method for gene rectification.100103

Genome engineering employing CRISPR/Cas has proven to be a strong method for quickly and accurately changing specific genomic sequences. The rise of innovative haematopoiesis research tools to examine the complexity of hematopoietic stem cell (HSC) biology has been fuelled by considerable advancements in CRISPR technology over the last five years. High-throughput CRISPR screenings using many new flavours of Cas and sequential and/or functional outcomes, in specific, have become more effective and practical.104,105

The power of the CRISPR/Cas system is that it can specifically and efficiently target sequences in the genome with just a single synthetic guide RNA (sgRNA) and a single protein. Cas9 is directed to the specific DNA sequence by the sgRNA, which causes double stranded breaks and activates the cells DNA repair processes. Non-homologous end joining can cause insertiondeletion (indel) substitutions at the target location, whereas homology-directed repair can use a template DNA to insert new genetic material.104,106

The possibility for CRISPR/Cas9 to be used in the hematopoietic system was emphasised as pretty shortly after it was initiated as a new genome editing method.106,107 The efficiency with which CRISPR-mediated alteration can be used to evaluate hematopoietic stem/progenitor and mature cell function via transplantation. As a result, hematopoietic research has significantly advanced with the implementation of these technologies. Whilst single-gene CRISPR/Cas9 programming is a significant tool for testing gene function in primary hematopoietic cells, high-throughput screenings potentially offer CRISPR/Cas9 an even greater advantage in hematopoietic research.104

While understanding human haematological disorders requires the ability to mimic diseases, the ultimate goal is to transfer this innovation into therapies. Despite significant advancements in CRISPR technology, there are still barriers to overcome before CRISPR/Cas9 can be used effectively and safely in humans. CRISPR has also been used to target CCR5 in CD34+ HSPCs in an effort to make immune cells resistant to HIV infection, as CCR5 is an important coreceptor for HIV infection.104

CRISPR is a modern genome editing technique that could be used to treat immunological illnesses including HIV. The utilization of CRISPR in stem cells for HIV-related investigation, on the other end, was ineffective, and much of the experiment was done in vivo. The new research idea is about increasing CRISPR-editing efficiencies in stem cell transplantation for HIV treatment, as well as its future perspective. The possible genes that enhance HIV resistance and stem cell engraftment should be explored more in the future studies. To strengthen HIV therapy or resistance, double knockout and knock-in approaches must be used to build a positive engraftment. In the future, CRISPR/SaCas9 and Ribonucleoprotein (RNP) administration should be explored in the further investigations.108 As well as some different title studies were explained the effectiveness of the CRISPR gene editing technology on the management of HIV/AIDS including: CRISPR view of hematopoietic stem cells: Moving innovative bioengineering into the clinic,104 CRISPR-Edited Stem Cells in a Patient with HIV and Acute Lymphocytic Leukaemia,109 Sequential LASER ART and CRISPR Treatments Eliminate HIV-1 in a Subset of Infected Humanized Mice,110 Extinction of all infectious HIV in cell culture by the CRISPR-Cas12a system with only a single crRNA,111 HIV-specific humoral immune responses by CRISPR/Cas9-edited B cells,112 CRISPR-Cas9 Mediated Exonic Disruption for HIV-1 Elimination,113 RNA-directed gene editing specifically eradicates latent and prevents new HIV-1 infection,114 CRISPR/Cas9 Ablation of Integrated HIV-1 Accumulates Pro viral DNA Circles with Reformed Long Terminal Repeats,115 CRISPR-Cas9-mediated gene disruption of HIV-1 co-receptors confers broad resistance to infection in human T cells and humanized mice,116 Inhibition of HIV-1 infection of primary CD4+ T-cells by gene editing of CCR5 using adenovirus-delivered CRISPR/Cas9,117 Transient CRISPR-Cas Treatment Can Prevent Reactivation of HIV-1 Replication in a Latently Infected T-Cell Line,118 CCR5 Gene Disruption via Lentiviral Vectors Expressing Cas9 and Single Guided RNA Renders Cells Resistant to HIV-1 Infection,119 CRISPR/Cas9-Mediated CCR5 Ablation in Human Hematopoietic Stem/Progenitor Cells Confers HIV-1 Resistance In Vivo.109

Induced pluripotent stem cells (iPSCs) have significantly advanced the field of regenerative medicine by allowing the generation of patient-specific pluripotent stem cells from adult individuals. The progress of iPSCs for HIV treatment has the potential to generate a continuous supply of therapeutic cells for transplantation into HIV-infected patients. The title of the study is reported on Generation of HIV-1 Resistant and Functional Macrophages from Hematopoietic Stem Cellderived Induced Pluripotent Stem Cells. In this investigation, researchers used human hematopoietic stem cells (HSCs) to produce anti-HIV gene expressing iPSCs for HIV gene therapy. HSCs were dedifferentiated into constantly growing iPSC lines using 4 reprogramming factors and a combination anti-HIV lentiviral vector comprising a CCR5 shRNA and a human/rhesus chimeric TRIM5 gene. After directing the anti-HIV iPSCs toward the hematopoietic lineage, a large number of colony-forming CD133+ HSCs were acquired. These cells were distinguished further into functional end-stage macrophages with a normal phenotypic profile. Upon viral challenge, the anti-HIV iPSC-derived macrophages displayed good protection against HIV-1 infection. Researchers have clearly shown how iPSCs can establish into HIV-1 resistant immune cells and explain their prospective use in HIV gene and cellular therapies.120

Some other similar titles of the studies reported on the effectiveness of IPSCs on HIV/AIDS managements are as follows: Generation of HIV-Resistant Macrophages from IPSCs by Using Transcriptional Gene Silencing and Promoter-Targeted RNA,121 Generation of HIV-1-infected patients gene-edited induced pluripotent stem cells using feeder-free culture conditions,122 A High-Throughput Method as a Diagnostic Tool for HIV Detection in Patient-Specific Induced Pluripotent Stem Cells Generated by Different Reprogramming Methods,123 Genetically edited CD34+ cells derived from human iPS cells in vivo but not in vitro engraft and differentiate into HIV-resistant cells,124 Engineered induced-pluripotent stem cell-derived monocyte extracellular vesicles alter inflammation in HIV humanized mice,125 Sustainable Antiviral Efficacy of Rejuvenated HIV-Specific Cytotoxic T Lymphocytes Generated from Induced Pluripotent Stem Cells.126

Recently, one HIV patient appeared to be virus-free after having undergone a stem-cell transfusion in which their WBCs were changed with HIV-resistant variations.84 Timothy Ray Brown also noted as the Berlin patient, who is still virus-free, was the first individual to undertake stem-cell transplantation a decade earlier. The most recent patient, like Brown, had a type of leukaemia that was vulnerable to chemo treatments. They required a bone marrow transplantation, which involved removing their blood cells and replacing them with stem cells from a donor cell.5,31,34,41,127130 Rather than simply choosing a suitable donor, Ravindra Gupta et al chose one who already had 2 copies of a mutant within the CCR5 gene,128,131 which provides resistance to HIV infection.3

Additionally, this gene encodes for a specific receptor of white blood cells that are assisted in the bodys immunological responses. The transplant, according to Guptas team, completely replaced the clients White cells with HIV-resistant forms.41,83 Cells in the patients blood disrupted expressing the CCR5 receptor, making it unfeasible for the clients form of HIV to infect the above cells again. The scientists determined that the virus had been cleared from the patients blood after the transplantation. Besides that, after 16 months, the client has withdrawn antiretroviral treatment. The infection was not detected in the most recent follow-up, which occurred 18 months after the treatment was discontinued. Adam, also known as the London patient, was the second person to be cured of HIV as a result of a stem cell transfusion. This discovery is an important step forward in HIV research because it may aid in the detection of potential future therapeutic interventions. It must be noted, but even so, that this is not an extensively used HIV treatment. For HIV-infected patients, antiretroviral drugs have been the foremost therapeutic option.3,31,41,94,129,130 It also encourages many investigators and clinicians to look at the use of stem cells in the treatment of a wide range of serious medical conditions. The reprogramming abilities of stem cells, as well as their accessibility, have created a window of opportunity in medical research. The clinical utility of stem cells is forecast to expand rapidly in the coming years.

On Feb 15, 2022, scientific researchers confirmed that a woman had become the 3rd person in history to be successfully treated for HIV, the virus that causes AIDS, after just receiving a stem-cell transfusion that has used cells from cord blood. Within those transplant recipients, adult hematopoietic stem cells have been used; these are stem cells that eventually develop into all blood cell types, which include white blood cells, these are a vital component of the immune framework. Even so, the woman who had fairly recently been completely cured of HIV infection had a more unique experience than that of the 2 men who were actually cured before her.132

The clients physician, Dr. JingMei Hsu of Weill Cornell Medicine in New York, informed them that, she had been discharged from the hospital just 17 days after her procedure was performed, even with no indications of graft vs host ailment. The woman was HIV-positive but also had acute myeloid leukaemia, a blood cancer of the bone marrow that affects blood-forming cells. She had likely received cord blood as a successful treatment for both her cancer and HIV once her doctors decided on a potential donor well with HIV-blocking gene mutation. Cord blood comprises a high accumulation of hematopoietic stem cells; the blood is obtained during a childs birth and donated by the parents.132

The patients donor was partly nearly matched, and she received stem cells from a close family member to enhance her immune function after the transfusion. The procedure was performed on the woman in August of 2017. She chose to discontinue taking antiretroviral drugs, the standardized HIV intervention, 37 months upon her transfusion. After more than 14 months, there is no evidence of the viral infection or antibodies against it in her blood. Umbilical cord blood, in reality, is much more commonly accessible and simpler to try to match to beneficiaries than bone marrow. Perhaps, some research suggests that the method could be more available to HIV patients than bone marrow transplantation. Nearly 38 million people worldwide are infected with HIV. The potential for using partly matched umbilical cord blood transplantation increases the chances of choosing appropriate suitable donors for these clients considerably.132

It is really exciting to see the earlier terminally ill diseases of being effectively treated. In recent times, there has been a surge of focus on stem cell research.3 Stem cell therapy advancements in inpatient care are receiving a growing amount of attention.20 HIV/AIDS has been and remains a significant health concern around the world. Effective control of the HIV pandemic will necessitate a thorough understanding of the viruss transmission.32

Despite concerns about full compliance and adverse reactions, HAART has demonstrated to be able to succeed and is a sign specifically targeted form of treatment against HIV advancement. As illustrated by the first case of HIV infection relapse attained by bone marrow transplant, anti-HIV HPSC-based stem cell treatment and genotype technology have established a possible future upcoming technique to try to combat HIV/AIDS.

Investigators have conducted experiments with engineering distinct anti-HIV genetic traits trying to target different phases of HIV infection utilizing advanced scientific modalities. In numerous in vivo and in vitro animal studies, HSPCs and successive mature cells were secured from HIV infection by trying to target genetic factors in the infection. Anti-HIV gene engineering of HSPCs is safe and efficacious.15

The number of stem-cell-based research trials has risen in recent years. Thousands of studies claiming to use stem cells in experimental therapies have been registered worldwide. Despite some promising results, the majority of clinical stem cell technologies are still in their early life. These achievements have drawn attention to the possibility of the potential and advancement of various promising stem cell treatments currently in development.11

HIV remains a major danger to humanity. This virus has developed the ability to evade antiretroviral medication, resulting in the death of individuals. Scientists are constantly looking for a treatment for HIV/AIDS that is both effective and efficient.52 The 1st treatments in HIV+ clients were conducted in the early 1980s, even though they were cognizant of their viral disease. Following these early cases, allogeneic SCT was used to treat HIV+ patients with associated cancer or other haematological disorders all over the world. Stem cell transplantation developments have also stimulated the improvement of innovative HIV therapeutic approaches, especially for large goals like eradication and relapse.60

Numerous stem cell therapy progressions have been recognized with autologous and allogeneic hematopoietic stem cell transplantation, as well as umbilical cord blood mesenchymal stem cell transplant in AIDS immunologic non-responders. Whereas this sector continues to advance and distinguishing directives for these cells become much more effective, totipotent stem cells such as hESC and the recently reported induced pluripotent stem cells (iPSC) could be very useful for genetic engineering methods to counter hematopoietic abnormalities such as HIV disease.133135

Immunocompromised people are at a higher risk of catching life-threatening diseases. The perseverance of latently infected cells, which is formed by viral genome inclusion into host cell chromosomes, is a significant challenge in HIV-1 elimination. Stem cell therapy is producing impressive patient outcomes, illustrating not only the broad relevance of these strategies but also the huge potential of cell and gene treatment using adult stem cells and somatic derivative products of pluripotent stem cells (PSCs).

Stem cells have enormous regeneration capacity, and a plethora of interesting therapeutic uses are on the frontier. This is a highly interdisciplinary scientific field. Evolutionary biologists, biological technicians, mechanical engineers, and others that have evolved novel concepts and decided to bring them to medical applications are required to make important contributions. Further to that, recent advancements in several different research areas may contribute to stem cell application forms that are novel. Several hurdles must be conquered, however, in the advancement of stem cells. On the other hand, this discipline appears to be a promising and rapidly expanding research area.

Stem cell-based approaches to HIV treatment resemble an innovative approach to trying to rebuild the ravaged bodys immune system with the utmost goal of eliminating the virus from the body. We will probably see effective experiments from the next new generation of stem cell-based strategies shortly, which will start serving as a base for the further development and use of these techniques in a range of treatment application areas for other chronic diseases.

My immense pleasure was mentioned to family members and friends, who supported and encouraged me in every activity.

There was no funding for this work.

The authors declare that they have no conflicts of interest in relation to this work.

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Originally posted here:
PROMISING STEM CELL THERAPY IN THE MANAGEMENT OF HIV & AIDS | BTT - Dove Medical Press

Stem Cells. Author manuscript; available in PMC 2020 Jul 1.

Published in final edited form as:

PMCID: PMC6658105

NIHMSID: NIHMS1024291

1NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland

1NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland

1NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland

2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA

3Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, USA

1NeuroRepair Department, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland

2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA

3Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, USA

Author contributions:

Barbara Lukomska: Conception and design, financial support, collection and/or assembly of data, final approval of manuscript

Miroslaw Janowski: Conception and design, financial support, collection and/or assembly of data, manuscript writing, final approval of manuscript

It was shown as long as half a century ago that bone marrow is a source of not only hematopoietic stem cells, but also stem cells of mesenchymal tissues. Then the term of mesenchymal stem cells (MSCs) has been coined in early 1990s and over a decade later the criteria for defining MSCs have been released by International Society for Cellular Therapy. The easy derivation from a variety of fetal and adult tissues and not demanding cell culture conditions made MSCs an attractive research object. It was followed by the avalanche of reports from preclinical studies on potentially therapeutic properties of MSCs such as immunomodulation, trophic support and capability for a spontaneous differentiation into connective tissue cells, and differentiation into majority of cell types upon specific inductive conditions. While ontogenesis, niche and heterogeneity of MSCs are still under investigation, there is a rapid boost of attempts in clinical applications of MSCs, especially for a flood of civilization-driven conditions in so quickly aging societies in not only developed countries, but also very populous developing world. The fields of regenerative medicine and oncology are particularly extensively addressed by MSC applications, in part due to paucity of traditional therapeutic options for these highly demanding and costly conditions. There are currently almost 1000 clinical trials from entire world registered at clinicaltrials.gov and it seems that we are starting to witness the snowball effect with MSCs becoming a powerful global industry, however spectacular effects of MSCs in clinic still need to be shown.

Keywords: Mesenchymal stem cells, clinical, differentiation, immunomodulation, paracrine activity, history

Friedenstein was one of the pioneers of the theory that bone marrow is a reservoir of stem cells of mesenchymal tissues in adult organisms. It was based on his observation at the turn of the 1960s and 1970s., that ectopic transplantation of bone marrow into the kidney capsule, results not only the proliferation of bone marrow cells, but also the formation of bone [1] (). This indicated the existence in the bone marrow of a second, in addition to hematopoietic cells, stem cell population giving rise to bone precursors. Due to the ability of these cells to create osteoblasts, Friedenstein gave them the name of osteogenic stem cells. Friedenstein was also the first to isolate from bone marrow adherent fibroblast-like cells with the ability to grow rapidly in vitro in the form of clonogenic colonies (CFU-F; colony forming unit-fibroblast). These cells derived from CFU-F colonies were characterized by the ability to differentiate in vitro not only to osteocytes, but also to chondrocytes and adipocytes. After transplantation of CFU-F colonies into the recipient, they were capable of co-formation of the bone marrow micro-environment [2,3]. The term mesenchymal stem cells has been proposed by Caplan in 1991 because of their ability to differentiate into more than one type of cells that form connective tissue in many organs [4]. This name has become very popular and is currently the most commonly used, even though it raised doubts about the degree of their stemness [5]. Today, there are many substitutes in the literature for the abbreviation of MSCs, including Multipotent Stromal Cells, Marrow Stromal Cells, Mesodermal Stem Cells, Mesenchymal Stromal Cells and many more. In its latest work, Caplan recommends renaming these cells to Medicinal Signaling Cells due to the emphasis on the mechanism of their therapeutic effects after transplantation, which is believed to be based mainly on the secretion of factors facilitating regenerative processes [6].

The roots of research on bone marrow-derived stem cells of connective tissue, which has been then named: mesenchymal stem cells

Due to the growing controversy regarding the nomenclature, the degree of stemness and the characteristics of the cells discovered by Friedenstein, the International Society for Cellular Therapy (ISCT) in 2006 published its position specifying the criteria defining the population of MSCs, which was accepted by the global scientific community. These guidelines recommend the use of the name multipotent mesenchymal stromal cells, however, the name mesenchymal stem cells still remains the most-used. The condition for the identification of MSCs is the growth of cells in vitro as a population adhering to the substrate, as well as in the case of cells of human origin, a phenotype characterized by the presence of CD73, CD90, CD105 surface antigens and the lack of expression of proteins such as: CD45, CD34, CD14, CD11b, CD79a or CD19 or class II histocompatibility complex antigens (HLA II, human leukocyte antigens class II). Moreover, these cells must have the ability to differentiate towards osteoblasts, adipocytes and chondroblasts [7,8]. In addition to the markers mentioned in the ISCT guidelines, the following antigens turned out to be useful in isolating the human MSCs from the bone marrow: STRO-1 (antigen of the bone marrow stromal-1 antigen, cell surface antigen expressed by stromal elements in human bone marrow-1), VCAM / CD106 (vascular cell adhesion molecule 1) and MCAM / CD146 (melanoma cell adhesion molecule), which characterizes cells growing in vitro in a adherent form, with a high degree of clonogenicity and multidirectional differentiation ability [911].

The common mesenchymal core in both versions of MSC abbreviation comes from the term mesenchyme, which is synonymous with mesenchymal tissue or embryonic connective tissue. It is used to refer to a group of cells present only in the developing embryo derived mainly from the third germ layer - mesoderm. During the development these cells migrate and diffuse throughout the body of the embryo. They give rise to cells that build connective tissue in adult organisms, such as bones, cartilage, tendons, ligaments, muscles and bone marrow. The view about the differentiation of MSCs during embryonic development from mesenchymal cells is widely spread [4]. This is due, inter alia, to the observed convergence in the expression of markers such as: vimentin, laminin 1, fibronectin and osteopontin, which are typical for mesoderm cells during embryonic development, as well as characteristic for in vitro adherent bone marrow stroma cells [12]. However, the true origin of MSCs is unknown. In the literature, we can find also reports indicating that they are ontogenetically associated with a group of cells derived from ectoderm, which originate from Sox1 + cells (SRY - sex determining region Y) that appear during the development of embryonic neuroectoderm and neural crest. These cells inhabit newborn bone marrow and meet the criteria corresponding to their designation as MSCs. However, with the development of animals, the population of these cells disappears and is replaced by cells with a different, unidentified origin [13]. It has also been shown that in the bone marrow of the developing mouse embryo, at least two MSCs populations with distinct expression of the nestin protein and the intensity of cell divisions can be distinguished. The former one originates from mesoderm that does not express nestin, and is characterized by intense proliferation and is involved in the process of creating the embryo skeleton. The latter one is derived from the cells of the neural crest, which expresses nestin and is non-dividing and remains passive during bone formation while in the adult organism contributes to a niche of hematopoietic cells [14]. It seems, therefore, that the ontogenesis of MSCs is associated with cells belonging to different germ layers and their original source determines the role and functions that they play in the adult body.

In 1978, the concept of a niche was defined as a place in the body that is settled by stem cells and whose environment allows them to be maintained in an undifferentiated state [15]. MSCs were first obtained from the bone marrow stroma where they constitute an element of stromal cells, participating in the production of signals modulating the maturation of hematopoietic cells. However, the precise location of the niche for MSCs has not been known so far. In the context of research results indicating that MSCs can be isolated from many mesoderm-derived tissues during embryonic development, a common element was sought for all sources from which MSCs can be isolated and a theory was proposed about the existence of their niche within the blood vessels that are present in all structures from which these cells were isolated.

Crisan and colleagues have shown that cells inhabiting the perivascular space of blood vessels, isolated from human tissues such as skeletal muscle, pancreas, adipose tissue and placenta, with the phenotype CD146 +, NG2 + (neuroglycan-2), PDGF-R + (-type platelet-derived growth factor receptor), ALP + expressing endothelial, hematopoietic and muscle cell markers described as pericytes were precursors for cells that after in vitro expansion meet the criteria for determining them as MSCs [16]. Analogously to the described by Friedenstein MSCs, CD146 + cells colonizing the perivascular space of sinusoidal sinus vessels, are responsible for the production of signals allowing the reconstruction of the bone marrow microenvironment after transplantation to heterotopic location [11]. Whats more, tracing the fate of pericytes in the process of rebuilding a damaged tooth in rodents has shown that they are transforming into odontoblasts, which arise from MSCs found in the pulp. However, the same studies showed that in the process of reconstruction of incisors in mice, a different population of odontoblasts, which is not formed from pericytes, but from MSCs of different origin migrating to the area of damage, prevailed quantitatively [17]. The second cell population associated with blood vessels, proposed as a counterpart of MSCs in the body is advent building cells with the CD34+ CD31- CD146- phenotype, which after isolation and in vitro culture meet the criteria defining the population as MSCs. However, these cells also have the ability to differentiate into pericytes [18,19]. Although pericytes and MSCs have a very similar gene expression profile as well as an analogical capacity for differentiation, it has been shown that the functionality of these cells varies. In vitro studies of endothelial cell interactions in co-culture with MSCs or pericytes have shown that only pericytes are able to form highly branched, dense, cylindrical structures with large diameter, typical for well-organized blood vessels, while isolated from the bone marrow MSCs do not have such abilities. Currently, it is believed that there is a link between pericytes and MSCs, but their mutual relations are not well defined. There are speculations that MSCs are an intermediate form of pericytes or their subpopulation, but there is still no conclusive evidence confirming this hypothesis [20,21].

While the cells fulfilling criteria for MSCs can be harvested from various tissues at all developmental stages (fetal, young, adult and aged) using their plastic adherence property, there are profound differences between obtained MSC populations [22,23]. Bone marrow was historically the first source from which MSCs were obtained, however, over time, there have been reports of the possibility of isolation from other sources of cells with similar properties. Mesenchymal cells are obtained from both tissues and secretions of the adult body, such as adipose tissue, peripheral blood, dental pulp, yellow ligament, menstrual blood, endometrium, milk from mothers, as well as fetal tissues: amniotic fluid, membranes, chorionic villi, placenta, umbilical cord, Wharton jelly, and umbilical cord blood [2437]. MSCs of fetal origin as compared to cells isolated from tissues of adult organisms are characterized by a faster rate of proliferation as well as a greater number of in vitro passages until senescence [38]. However, MSCs derived from bone marrow and adipose tissue are able to create a larger number of CFU-F colonies, which indirectly indicates a higher degree of their stemness. The comparison of gene expression typical for pluripotent cells shows that only in cells isolated from the bone marrow we can observe the expression of the SOX2 gene, the activation of which is associated with the self-renewal process of stem cells as well as with neurogenesis during embryonic development [39]. Discrepancies in the ability of MSCs obtained from various sources to differentiate have also been described. The lack of differentiation of MSCs derived from umbilical cord blood towards adipocytes as well as the greater tendency of MSCs from bone marrow and adipose tissue to differentiate towards osteoblasts were observed [39,40].

In addition to the diverseness observed between MSCs from different sources, there are also differences associated with obtaining them from individual donors. Among the cells isolated from the bone marrow from donors of different ages and sexes, up to 12-fold differences in the rate of their proliferation and osteogenesis were found, combined with a 40-fold difference in the level of bone remodeling marker activity - ALP (alkaline phosphatase). At the same time, no correlations were found resulting from differences in the sex or age of donors [41]. However, the results of studies by other authors indicate that the properties of MSCs isolated from the bone marrow are strongly associated with the age of the donor. Cells collected from older donors are characterized by an increased percentage of apoptotic cells and slower rate of proliferation, which is associated with an increased population doubling time. There is also a weakened ability of MSCs from older donors to differentiate towards osteoblasts [42]. Heo in his work shows the different ability of MSCs to osteogenesis combining it with different levels of DLX5 gene expression (transcription factor with the homeodomain 5 motif) in individual donors, however independent of the type of tissue from which the cells were isolated [39].

The next stage in which we can observe diversity among the MSCs population is in vitro culture. The morphology of cultured cells that originate from the same isolation allows for differentiation into three sub-populations. There are observed spindle-shaped proliferating cells resembling fibroblasts (type I); large, flat cells with a clearly marked cytoskeleton structure, containing a number of granules (type II) and small, round cells with high self-renewal capacity [43,44]. The original hypothesis assumed that all cells that make up the MSCs population are multipotent, and each colony of CFU is capable of differentiating into adipocytes, chondrocytes and osteoblasts, as confirmed by appropriate studies [45]. However, in the literature we can find reports that cell lines derived from a common colony of CFU-F differ in their properties, characterized by uni-, di- or multipotence [46]. Some of the authors showed the division of clonogenic MSCs colonies into as much as eight groups distinct in their potential for differentiation. At the same time, it is suggested that there is a hierarchy within which cells subordinate to each other are increasingly directed towards osteo- chondro- or adipocytes and gradually lose their multipotential properties to di- and unipotential ones. This transformation may also be associated with a decrease in the rate of cell proliferation and the level of CD146 protein expression (CD; cluster of differentiation) - proposed as a marker of multipotency [47].

One of the main advantages of MSCs are their immunomodulatory properties. MSCs grown in vitro have the ability to interact and regulate the function of the majority of effector cells involved in the processes of primary and acquired immune response () [48]. They exert their immunomodulatory effects by inhibiting the complement-mediated effects of peripheral blood mononuclear cell proliferation [49,50], blocking apoptosis of native and activated neutrophils, as well as reducing the number of neutrophils binding to vascular endothelial cells, limiting the mobilization of these cells to the area of damage [51,52]. In addition, cytokines synthesized by activated MSCs stimulate neutrophil chemotaxis and secretion of pro-inflammatory chemokines involved in recruitment and stimulation of phagocytic macrophage properties [53]. Moreover MSCs limit mast cell degranulation, secretion of pro-inflammatory cytokines by these cells as well as their migration towards the chemotactic factors [54]. Native MSCs have the ability to block the proliferation of de novo-induced NK cells, but they are only able to partially inhibit the proliferation of already activated cells [55]. They also contribute to the reduction of cytotoxic activity of NK cells [56]. Moreover MSCs can block the differentiation of CD34 + cells isolated from the bone marrow or blood monocytes into mature dendritic cells both by direct contact as well as by secreted paracrine factors [57,58]. They inhibit the transformation of immature dendritic cells into mature forms and limit the mobilization of dendritic cells to the tissues [59]. Under their influence, M1 (pro-inflammatory) macrophages are transformed into M2 type cells with an anti-inflammatory phenotype, and the IL-10 (IL, interleukin) secreted by them inhibits T-cell proliferation [60,61]. In vitro studies have demonstrated a direct immunomodulatory effect of MSCs on lymphocytes. During the co-culture of MSCs with lymphocytes, suppression of activated CD4 + and CD8 + T cells and B lymphocytes was observed [62]. In addition, MSCs reduce the level of pro-inflammatory cytokines synthesized by T-lymphocytes, such as TNF- (tumor necrosis factor ) and IFN- (interferon ) [63], and increase synthesis of anti-inflammatory cytokines, e.g. IL-4. In the presence of MSCs, the inhibition of the differentiation of naive CD4 + T lymphocytes to Th17 + lymphocytes (Th; T helper cells) was observed, while the percentage of T cells differentiating towards CD4 + CD25 + regulatory T cells was found to increase [64,65]. Glennie et al. described this condition as anergy of activated T cells in the presence of MSCs [62]. MSCs also have the ability to limit the synthesis of immunoglobulins like IgM, IgG and IgA (Ig; immunoglobulin) classes secreted by activated B cells, thereby blocking the differentiation of these cells to plasma cells. They also reduce the expression of chemokines and their receptors on the surface of B lymphocytes, which probably have a negative effect on their ability to migrate [66].

The schematic representation of immunomodulatory capabilities of MSCs

Mesenchymal stem cells secrete a wide range of paracrine factors, collectively referred to as the secretome, which support regenerative processes in damaged tissues. They comprise the components of the extracellular matrix, proteins involved in the adhesion process, enzymes as well as their activators and inhibitors, growth factors and binding proteins, cytokines and chemokines, and probably many more [67]. These factors can have distinct impact on the processes they regulate (). MSCs secrete factors promoting angiogenesis, such as: vascular endothelial growth factor (VEGF) but they may also inhibit this process, through expression of monokine induced by interferon and tissue inhibitors of metalloproteinases 1 and 2 [68,69]. An important role is also played by chemokines secreted by MSCs in the process of blocking or stimulating cell chemotaxis, such as: CCL5 (RANTES, regulated by activation, expression and secretion by normal T lymphocytes), CXCL12 (SDF-1, stromal cell-derived factor 1) or CCL8 (MCP-2; monocyte chemoattractant protein 2). An essential group of factors from the point of view of regeneration processes are growth factors with an anti-apoptotic effect, including: HGF (hepatocyte growth factor), IGF-1 (insulin-like growth factor 1), VEGF, CINC-3 (cytokine induced by a chemoattractant for neutrophil chemoattractant), TIMP-1 (tissue inhibitor of metalloproteinases 1), TIMP-2 (tissue inhibitor of metalloproteinases 2), osteopontin, growth hormone, FGF-BP (bFGF binding protein), and BDNF (brain-derived growth factor; -derived neurotrophic factor) and stimulating proliferation as: TGF- (transforming growth factor ), HGF, EGF (epidermal growth factor), NGF (nerve growth factor; nerve growth factor), bFGF (basic fibroblast growth factor), IGFBP-1, IGFBP-2 (IGFBP; insulin-like growth factor 1 binding protein, IGF-Protein-1 protein) and M-CSF (stimulant factor t molar macrophage colony; macrophage colony-stimulating factor) [68,70,71]. Growth factors secreted by MSCs have also ability to reduce fibrosis of tissues during regeneration. These include KGF (keratinocyte growth factor), HGF, VEGF, and Ang-1 (angiopoietin-1), SDF1, IGF-1, EGF, HGF, NGF, TGF- [71,72]. There are reports about the antibacterial properties and interaction of the MSC secretome with cancer cells. Data on the impact of MSCs on neoplasia are not conclusive, however, it is assumed that both the tumor type and the origin of MSCs are of great importance for the final effect [73]. It was shown that factors enclosed within the MSCs secretome are able to reduce the proliferation, viability and migration of certain types of cancer cells (such as non-small-cell lung carcinoma) [74]. Others have shown that factors released by MSCs may increase motility, invasiveness and the ability to form metastases (including, for example, breast cancer cells) [75]. In response to bacteria, levels of cytokines such as IL- 6, IL-8, CCL5, PGE2, TNF-, IL-1, IL-10, VEGF and SDF-1 secreted by MSCs are subject to change [76]. MSCs contain also substances with antibacterial, anti-parasitic and antiviral activity [77].

The mechanisms mediating MSC-dependent trophic support

Another broad and dynamically developing field in recent years which is related to paracrine MSCs activity is their ability to secrete extracellular vesicles (EVs), which include exosomes, microvesicles and apoptotic bodies. Their composition largely coincides with the components contained in the cells from which they originate. Physiologically they play an important role in the regulation of biological functions, homeostasis and the immune response of the body. It is also postulated that the biological activity of microvesicles is comparable to that of MSCs [78]. Experiments conducted using supernatant derived from in vitro culture of MSCs showed that the factors contained in their secretome are responsible for a large part of the effects exerted by MSCs during the regeneration of the damaged area including the protection of other cells against apoptosis, induction of their proliferation, prevention of excessive fibrosis of tissues, stimulation of the angiogenesis process and immunomodulatory effects, as well as the induction of endogenous stem cells differentiation [65,68,69,7982].

As mentioned above, the ability to differentiate into three types of cells such as: osteocytes, chondrocytes and adipocytes is one of the criterion for MSCs [8]. This phenomenon can be traced in vitro by placing MSCs in a medium containing specific supplements, for the adipogenesis process they are mainly dexamethasone, indomethacin, insulin and isobutylmethylxanthin [83], for chondrogenesis cell culture in DMEM medium (Dulbecco / Vogt Modified Eagles Minimal Essential Medium) supplemented with insulin, transferrin, selenium, linoleic acid, selenium acid, pyruvate, ascorbic phosphate, dexamethasone and TGF- III [84], which may additionally be aided by the addition of IGF-1 and BMP-2 (BMP; bone morphogenetic proteins) [85]. In turn the osteogenesis is induced by the presence of ascorbic acid, -glycerophosphate and dexamethasone [86]. Differentiation of MSCs in the appropriate cell type is assessed by identifying the production of respectively: fat droplets (adipogenesis), proteoglycans and type II collagen synthesis (chondrogenesis) or mineralization of calcium deposits and the increase of alkaline phosphatase expression (osteogenesis). However, many literature reports indicate that by the treatment with appropriate factors MSCs might be also a source of other cell types. Caplan and Dennis in their work from 2006 present a process that they call mesengenesis, in which MSCs give also rise to myoblasts, bone marrow stromal cells, fibroblasts, cells co-creating connective tissue of the body as well as ligaments and tendons [87]. Addition of 5-azacytidine to MSCs allows to obtain muscle cells, including cardiomyocytes and myoblasts having the ability to create multinucleated miotubes and expressing markers such as: -myosin heavy chain, -actin cardiac form and desmin [88]. In addition, in vitro studies have made it possible to obtain from MSCs at least two types of cells derived from the endoderm through their transdifferentiation into hepatocytes and -cells of pancreatic islets. The liver cells are obtained from MSCs in two stages by culturing them in modified Dulbeccos medium supplemented with EGF, bFGF and nicotinamide, and in the next stage with the addition of oncostatin M, dexamethasone, insulin, transferrin and selenium. The resulting cells show the presence of markers typical for hepatocytes such as albumin, -fetoprotein and hepatocyte nuclear factor 4 (HNF-4) [89]. By the treatment with a mixture of growth factors secreted by regenerating cells of the pancreas as well as by the use of acitin A, sodium butyrate, taurine and nicotinamide the pancreatic islets of -cells capable of producing insulin were obtained from MSCs [90,91]. It has also been shown that stimulation with appropriate factors may result in the differentiation of MSCs into cells derived ontogenetically from ectoderm, such as neurons. The use of BME stimulation in vitro (-mercaptoethanol) followed by NGF leads to the differentiation of MSCs into cholinergic nerve cells expressing their typical proteins such as NF-68 neurofilaments (68 kDa Neurofilament protein with 68 kDa molecular mass), NF-200 (neurofilament protein with a molecular weight 200kDa, 200kDa neurofilament protein), NF-160 (neurofilament protein molecular weight 160kDa, 160kDa neurofilament protein), choline acetyltransferase and synapsin I [92]. Other factors mentioned as compounds inducing the transformation of MSCs into nerve cells are insulin, retinoic acid, bFGF, EGF, valproic acid, BME and hydrocortisol [93]. In addition, GNDF (glial cell-derived neurotrophic factor), BDNF (brain-derived neurotrophic factor), retinoic acid, 5-azacytidine, isobutylmethylxanthine and indomethacin stimulate the transformation of MSCs into mature neurons that express markers of nervous systems cells such as: nestin, -III tubulin, microtubule associated protein - MAP2 (microtubule associated protein 2) and neuron-specific enolase (ENO2; enolase 2) [94]. These studies show that under strictly controlled conditions prevailing during in vitro culture, in the presence of chemicals and growth factors, MSCs are able to turn into cells derived from all three embryonic germ layers ().

The differentiation potential of MSCs

It has been more than half a century since the curiosity has been revealed that not only hematopoietic cells, but also those capable of forming connective tissue reside in the bone marrow. Subsequent studies have begun to reveal the increasingly fascinating properties of these cells, which go far beyond forming connective tissue. This, combined with their easy derivation from various tissues, made them an attractive research object. Immunomodulatory properties, aiding repair of various tissues as well as differentiation potential to practically any types of cells stunned a whole host of scientists and established MSCs as a driving force of regenerative medicine and began also to play an increasingly important role in oncology [95]. We are currently observing a flood of clinical trials with the use of MSCs, and their number doubles every few years and currently reaches almost 1000 registered items on the clinicaltrials.gov website.

MSCs compose a negligible fraction of cells derived from in vivo tissues and there is no effective method to capture them directly. Therefore, MSCs need to be subjected to the process of in vitro expansion, which in clinical context is called biomanufacturing and biobanking and both terms are frequently used interchangeably to describe the process from procurement of cell source to deliver cells to the patients bed. The processing of MSCs must be performed according to current Good Manufacturing Practice (cGMP) as any other therapeutic agent and is subjected to extensive regulatory effort. Food and Drug Administration (FDA) is the main authority responsible for acceptance of medical products including those containing living cells such as MSCs in the USA. FDA has issued a perspective on MSC-based product characterization [96] and up-dated it in FDA Grand Round delivered by Steven Bauer, PhD, Chief of Cell and Tissue Therapies Branch at FDA on March 08, 2018. Both sources are an excellent overview of regulatory challenges related to the biobanking of MSCs. In general, any new product must obtain investigational new drug status (INDs) to be used in clinical trial before filing application for marketing, and there were 66 INDs submitted to FDA between 2006 and 2012. Based on that FDA engaged into regulatory research project called MSC consortium to characterize MSC based-products with an output of 16 research papers. The main organ responsible for the regulation of medical market in all Member States is European Medicines Agency (EMA) consisting of seven smaller committees. The MSCs-containing products should be classified as Advanced Therapy Medical Product (ATMP) and in detail considered as Somatic Cell Therapy Medicinal Product (CTMP) [97]. Its release on medical market has to be first accredited by Committee for Advanced Therapies (CAT) which creates the general opinion and evaluates the quality, safety and efficiency of the product. After CAT assessment the final acceptance should be then approved by Committee for the Medicinal Products for Human Use (CHMP). This type of legalization is called Centralized Marketing Authorization and it allows to use ATMP products in all European Union countries. Currently, there is a variety of protocols used for biomanufacturing and biobanking of MSCs, and once the successful stories become strong, the landscape of MSC production will probably solidify with predicted reduction of MSC production approaches due to economic and regulatory pressures.

Summing up, it seems that the MSCs are becoming a powerful global industry, ready to respond to the unmet needs of modern medicine struggling with the proper care and quality of life of rapidly aging societies, which is already affecting not only developed countries, but also very populous developing countries. In conclusion, we are beginning to observe the effect of the snowball in which ever new discoveries related to MSC are increasingly stimulating clinical applications of the MSC, which is beginning to contribute to the transformation of medical care.

Significance Statement

The research on bone marrow-derived stem cells of connective tissue is evolving and continuously expanding with a recent boost of interest in clinical applications reflected by an avalanche of nearly 1000 registered clinical trials. While, the current name: mesenchymal stem cells (MSCs) have been coined as late as early 90-ies, it is important to commemorate of the fiftieth anniversary of research on them and provide a big picture from roots of first paper in 1968, through identification of their various potential therapeutic activities such as immunomodulation, trophic support and capability for differentiation and taking role in cell replacement strategies.

This work was funded by NCR&D grant EXPLORE ME within the STRATEGMED I program and by NIH R01 NS091100-01A1.

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Mesenchymal stem cells: from roots to boost - PMC

Lab-grown human heart cells provide a powerful tool to understand and potentially treat heart disease. However, the methods to produce human heart cells from pluripotent stem cells are not optimal. Fortunately, a new study out of the University of WisconsinMadison Stem Cell & Regenerative Medicine Center is providing key insight that will aid researchers in growing cardiac cells from stem cells.

The research, published recently in eLife, investigates the role of extracellular matrix (ECM) proteins in the generation of heart cells derived from human pluripotent stem cells (hPSCs). The ECM fills the space between cells, providing structural support and regulating formation of tissues and organs. With a better understanding of ECM and its impact on heart development, researchers will be able to more effectively develop heart muscle cells, called cardiomyocytes, that could be useful for cardiac repair, regeneration and cell therapy.

How the ECM impacts the generation of hPSC-cardiomyocytes has been largely overlooked, says Jianhua Zhang, a senior scientist at the Stem Cell and Regenerative Medicine Center. The better we understand how the soluble factors as well as the ECM proteins work in the cell culture and differentiation, the closer we get to our goals.

Researchers like Zhang have been looking to improve the differentiation of hPSCs into cardiomyocytes, or the ability to take hPSCs, which can self-renew indefinitely in culture while maintaining the ability to become almost any cell type in the human body and turn them into heart muscle cells. To investigate the role of the ECM in promoting this cardiac differentiation of hPSCs, Zhang tested a variety of proteins to see how they impacted stem cell growth and differentiation specifically, ECM proteins including laminin-111, laminin-521, fibronectin and collagen.

Our study showed ECM proteins play significant roles in the hPSC adhesion, growth, and cardiac differentiation. And fibronectin plays an essential role and is indispensable in hPSC cardiac differentiation, says Zhang. By understanding the roles of ECM, this study will help to develop more robust methods and protocols for generation of hPSC-CMs. Furthermore, this study not only helps in the field for cardiac differentiation, but also other lineage differentiation as well.

While the new study provides important insight into heart cell development, it is built upon a 2012 study Zhang led which looked at the most efficient way to develop cardiac differentiation of stem cells.

This study is actually a follow-up paper to the Matrix Sandwich Method that we developed for efficient cardiac differentiation of hPSCs, Zhang says. In order to culture the stem cells, we needed to have an ECM layer on the bottom of the plate. Otherwise, the stem cells would not attach to the plate. We would then add another layer of ECM on top of the growing stem cells, and we found that this helped promote the most effective differentiation.

While it was clear that this layering, or sandwich, method more efficiently and reproducibly differentiated hPSC-cardiomyocytes, researchers did not fully understand why. The new study explains why the ECM layers are crucial and identifies fibronectin as a key ECM protein in the development of hPSC-cardiomyocytes.

The most exciting part of this study is now I understand why the Matrix Sandwich Method worked. We were able to identify the fibronectin and its integrin receptors as well as the downstream signaling pathways in this study, Zhang explains. With a better understanding of ECMs roles in stem cell growth and cardiac differentiation, we now hope to investigate the roles of fibronectin and other ECM proteins in promoting the hPSC-cardiomyocytes transplantation for cell therapy.

The next step could help researchers realize the full potential of using hPSC-cardiomyocytes for disease modeling, drug screening, cardiac regeneration and cell therapy. This is very meaningful to Zhang, who began working in cardiovascular research more than 16 years ago.

I became interested in stem cell and heart research when I began working with the stem cells and saw them turning into heart cells beating in a cell culture dish under a microscope, Zhang says. It was amazing. Ive become more and more dedicated to this research, and I can really see the potential of using the stem cell technologies to cure disease and improve our health.

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New study allows researchers to more efficiently form human heart cells from stem cells - University of Wisconsin-Madison

Wilmington, Delaware, United States, Transparency Market Research Inc.: Cell line development is an important technology in life sciences. Stable cell lines are used for various applications including monoclonal antibody and recombinant protein productions, gene functional studies, and drug screening

Read Report Overview - https://www.transparencymarketresearch.com/cell-line-development-market.html

Manual screening method is a traditional method used for cell line development. This method is tend to be disadvantageous as it is labor-intensive and time-consuming. Automation in tools used for cell line development is likely to replace manual methods of cell line development.

Cell line development and culturing is being rapidly adopted in areas of biological drug developments for various chronic diseases, regenerative medicines such as stem cells & cell-based therapies, recombinant protein, and other cellular entities for pharmaceuticals, diagnostics, and various other industries.

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Key Drivers and Opportunities of Global Cell Line Development Market

Rise in focus on research & development, owing to increase in prevalence of cancer and other chronic diseases is anticipated to drive the market. Several institutes, such as Cancer Research Institute, National Cancer Institute, Advanced Centre for Treatment, Research and Education in Cancer (Cancer Research Centre [ICRC]), and NCI Community Oncology Research Program (NCORP), are engaged in research & development for cancer diagnosis and treatment. Hence, the initiative of government and non-government organizations is likely boost the growth of the market.

Mammalian cell lines are widely used as production tools for various biologic drugs. Technological advancement in cell line development in mammalian cell culturing is likely to fuel the growth of the market. For instance, according to an article published in Pharmaceuticals (Basel), the U.S. Food and Drug Administered approved 15 novel recombinant protein therapeutics from 2005 to 2011 on an average.

Advances in bioinformatics and recombinant technologies have led to development of new cell lines for synthesis or production of essential peptides, enzymes, saccharides, and other molecules which are being used in pharmaceuticals and various other industries.

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North America to Capture Major Share of Global Cell Line Development Market

North America is expected to account for major share of the global cell line development market due to well-established health care infrastructure and rise in government initiatives. Furthermore, adoption of innovative technologies is likely to augment the market in the region.

The cell line development market in Asia Pacific is expected to grow at a rapid pace during the forecast period, owing to increasing risk of communicable diseases, cancer, and chronic & rare diseases and surge in geriatric population. For instance, according to an article published in BioMed Central Ltd, in 2018, 2.9 million cancer deaths occurred and 4.3 million new cancer cases were recorded in China.

Key Players Operating in Global Cell Line Development Market

The global cell line development market is highly concentrated due to the presence of key players. A large number of manufacturers hold major share in their respective regions. Key players engaged in adopting new strategies are likely to drive the global cell line development market. Key players are developing new, cost-effective biologic products. This is anticipated to augment the market.

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Major players operating in the global cell line development market are:

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Cell Line Development Market: Increase in Prevalence of Cancer and Other Chronic Diseases to Drive the Market - BioSpace

Homology Medicines, Inc.

AAVHSC16 Biodistribution Properties in Preclinical Models Demonstrated Potential for Systemic Delivery of Genetic Medicines to Brain, Heart and Muscle

BEDFORD, Mass., July 05, 2022 (GLOBE NEWSWIRE) -- Homology Medicines, Inc. (Nasdaq: FIXX), a genetic medicines company, announced today the peer-reviewed publication of data showing that AAVHSC16, one of the capsids in its family of 15 naturally occurring AAVHSCs, demonstrated low levels of tropism to the liver while maintaining robust distribution to the central nervous system (CNS) and peripheral organs following a single I.V. administration in preclinical models. The Company believes that its unique properties, with high levels of tropism to the brain, heart and muscle, and no elevations in liver enzymes, could make AAVHSC16 an attractive capsid for new disease indications with Homologys genetic medicines platform.

Our ongoing efforts to fully characterize our family of 15 naturally occurring AAVHSCs as it relates to biodistribution, tissue tropism and the role different features of the capsids play, continues to reveal their unique profiles that allow us to best select capsids for different diseases, said Albert Seymour, Ph.D., President and Chief Scientific Officer of Homology Medicines. In the case of AAVHSC16 with its ability to reach key tissues without targeting the liver in preclinical models, we can potentially expand into additional disease areas where we want to deliver to the CNS, cardiac tissue, or muscle while avoiding exposure in the liver. By continuing to publish our discoveries about the unique structure and function of our AAVHSCs, we believe we can contribute to the fields greater understanding and development of AAV-based therapies that will ultimately benefit more patients.

Homologys AAVHSC capsids differ from each other by one to four amino acids, resulting in differences in biodistribution and transduction efficiencies. As described in the manuscript, AAVHSC16 has two unique amino acids, 501I and 706C, in addition to 505R that is shared across six AAVHSC serotypes. A series of experiments demonstrated that these amino acids contribute to AAVHSC16s unique properties, which include significantly reduced liver tropism compared to other AAVs, no liver enzyme elevations, and high tissue tropism to the CNS and other peripheral organs. Specifically, these data demonstrated:

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Naturally Occurring Variations in AAVHSC16 Alter Cellular Binding Affinity In Vitro

AAVHSC16 does not share the galactose (a type of glycan) binding feature of other AAVHSCs and Clade F AAVs in vitro. AAVHSC16 did not show improved binding or a difference in number of vector genomes (vgs) or eGFP expression in cells with terminally exposed galactose, while other AAVHSCs tested did.

The combination of the unique naturally occurring amino acids at positions 501I and 505R in AAVHSC16 were shown to contribute to reduced galactose-binding.

AAVHSC16 Has Significantly Reduced Liver Transduction in In Vivo and In Vitro Models, with High Tropism to other Tissues Following a Single I.V. Administration

In murine models, a single I.V. administration of AAVHSC16 showed significantly lower levels of liver tropism compared to AAVHSC15 and AAV9. The liver was the only organ with significant differences as AAVHSC16 demonstrated high levels of tropism to all other organs evaluated, including the brain, heart and muscle; these levels were comparable to those observed with AAVHSC15 and AAV9.

Further, in non-human primates (NHPs), a single I.V. administration of AAVHSC16 resulted in substantially lower liver expression than AAVHSC15, while maintaining high and equivalent levels of transduction in the brain, heart and muscle.

In vitro data also showed that AAVHSC16 led to lower expression in primary human liver cells compared to other tested wild type AAVHSCs and AAV9, and it revealed that AAVHSC16s 706 residue was the main contributor to this outcome.

AAVHSC16 Did Not Lead to Elevations in Liver Function Tests

In NHPs, a single I.V. administration of AAVHSC16 at 7E+13 and 1E+14 vg/kg doses did not result in elevated ALT (alanine transaminase) or AST (aspartate transferase) levels at any timepoint post-dose compared to baseline levels or vehicle-treated controls.

Comparing AAVHSC16 liver transduction and ALT and AST levels to AAV9 and other AAVHSCs further suggested that the lack of ALT and AST elevations with AAVHSC16 is associated with its lower liver tropism.

The publication, Natural Variations in AAVHSC16 Significantly Reduce Liver Tropism and Maintain Broad Distribution to Periphery and CNS, was peer-reviewed and published in the journal Molecular Therapy - Methods & Clinical Development. For more information, please click here or http://www.homologymedicines.com/publications.

About Homology Medicines, Inc.Homology Medicines, Inc. is a clinical-stage genetic medicines company dedicated to transforming the lives of patients suffering from rare diseases by addressing the underlying cause of the disease. The Companys clinical programs include HMI-102, an investigational gene therapy for adults with phenylketonuria (PKU); HMI-103, a gene editing candidate for PKU; and HMI-203, an investigational gene therapy for Hunter syndrome. Additional programs focus on metachromatic leukodystrophy (MLD), paroxysmal nocturnal hemoglobinuria (PNH) and other diseases. Homologys proprietary platform is designed to utilize its family of 15 human hematopoietic stem cell-derived adeno-associated virus (AAVHSCs) vectors to precisely and efficiently deliver genetic medicines in vivo through a gene therapy or nuclease-free gene editing modality, as well as to deliver one-time gene therapy to produce antibodies throughout the body through the GTx-mAb platform. Homology has a management team with a successful track record of discovering, developing and commercializing therapeutics with a focus on rare diseases. Homology believes its initial clinical data and compelling preclinical data, scientific and product development expertise and broad intellectual property position the Company as a leader in genetic medicines. For more information, visit http://www.homologymedicines.com.

Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including, without limitation, statements regarding the potential to expand the application of AAVHSC16 to other disease areas; our expectations surrounding the potential, safety, and efficacy of our product candidates; the potential of our gene therapy and gene editing platforms; and our position as a leader in the development of genetic medicines. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: the impact of the COVID-19 pandemic on our business and operations, including our preclinical studies and clinical trials, and on general economic conditions; we have and expect to continue to incur significant losses; our need for additional funding, which may not be available; failure to identify additional product candidates and develop or commercialize marketable products; the early stage of our development efforts; potential unforeseen events during clinical trials could cause delays or other adverse consequences; risks relating to the regulatory approval process; interim, topline and preliminary data may change as more patient data become available, and are subject to audit and verification procedures that could result in material changes in the final data; our product candidates may cause serious adverse side effects; inability to maintain our collaborations, or the failure of these collaborations; our reliance on third parties, including for the manufacture of materials for our research programs, preclinical and clinical studies; failure to obtain U.S. or international marketing approval; ongoing regulatory obligations; effects of significant competition; unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives; product liability lawsuits; securities class action litigation; failure to attract, retain and motivate qualified personnel; the possibility of system failures or security breaches; risks relating to intellectual property; risks associated with international operations, such as political and economic instability, including in light of the conflict between Russia and Ukraine; and significant costs incurred as a result of operating as a public company. These and other important factors discussed under the caption Risk Factors in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2022, and our other filings with the Securities and Exchange Commission (SEC) could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent managements estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change.

Company Contacts:Theresa McNeelyChief Communications Officer and Patient Advocatetmcneely@homologymedicines.com781-301-7277

Media Contact:Cara Mayfield Vice President, Patient Advocacy and Corporate Communications cmayfield@homologymedicines.com 781-691-3510

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Homology Medicines Announces Peer-Reviewed Publication on Novel Discovery of AAVHSC with Robust Distribution to the Central Nervous System and...

Global Surgical Mesh Market Is Estimated To Be Valued At US$ 1.29 Bn In 2022, And Is Forecast To Surpass US$ 2.2 Bn Valuation By The End Of 2032

Sales of surgical meshes are expected to account for more than 21 Mn units by 2032-end, owing to their increasing application in untapped markets, says a Fact.MR analyst.

Fact.MR A Market Research and Competitive Intelligence Provider: The global surgical mesh market is estimated to exceed a valuation of US$ 1.29 Bn in 2022, and expand at a significant CAGR of 5.5% by value over the assessment period (2022-2032).

The availability of surgical meshes in absorbable and non-absorbable forms has expanded their application for temporary as well as permanent reinforcement. In recent years, demand for surgical meshes has escalated in aiding breast reconstruction as they reduce the exposure risk of the implant. Increasing health literacy in North America and Europe will create ample opportunities for surgical mesh manufacturers over the coming years.

Sedentary lifestyle and increasing obesity among the population have resulted in several chronic health issues. The consequent weakening of the muscles extends space for organ prolapse and hernia. Putting these organs back in place by stitching the muscles together can result in muscle tearing and the recurrence of prolapse. However, reinforcing the weakened muscles with the help of a surgical mesh has shown to decrease recurrence and increase the longevity of the repair.

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Key Takeaways from Market Study

Winning Strategy

To attract new customers, market players are focusing on portfolio enhancement. Robust investments in R&D are driving product innovation for key market players. Meshes inhibiting the growth of bacterial films and preventing tissue adhesions are luring new consumers. Collaboration of manufacturers with scientific personnel and operating surgeons have enabled bespoke designing of meshes to best fit patients needs.

Manufacturers are also aiming for portfolio expansion through acquisition and partnerships. Partnering with companies that offer a well-aligned portfolio has significantly increased consumer penetration for key manufacturers. However, augmenting relations with local players and operating surgeons will be a key determinant of the products commercial success.

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Scientific collaborations and robust R&D investments have also guided product innovation and became a common strategic approach adopted by leading surgical mesh manufacturing companies to upscale their market presence.

For instance:

Surgical Mesh Industry Research by Category

Surgical Mesh Market by Product Type:

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Surgical Mesh Market by Surgical Access:

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Surgical Mesh Market by Raw Material:

Surgical Mesh Market by Region:

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Fact.MR, in its new offering, presents an unbiased analysis of the global surgical mesh market, presenting historical market data (2017-2021) and forecast statistics for the period of 2022-2032.

The study reveals essential insights on the basis of product type (synthetic, biosynthetic, biologic, hybrid/composite), nature of mesh (absorbable, non-absorbable, partially absorbable), surgical access (open surgery, laparoscopic surgery), use case (hernia repair, pelvic floor disorder treatment, breast reconstruction, others), and raw material (polypropylene, polyethylene terephthalate, expanded polytetrafluoroethylene, polyglycolic acid, decellularized dermis/ECM, others), across seven major regions (North America, Latin America, Europe, East Asia, South Asia & ASEAN, Oceania, MEA).

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Expert analysis, actionable insights, and strategic recommendations of the highly seasoned healthcare team at Fact.MR helps clients from across the globe with their unique business intelligence needs

With a repertoire of over thousand reports and 1 million-plus data points, the team has analysed the healthcare domain across 50+ countries for over a decade. The team provides unmatched end-to-end research and consulting services.

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Technical Advancements & Innovative Products Likely to Expand Application of Surgical Meshes in Untapped Domains, States Fact.MR - BioSpace

A paper recently published in the journal Biomaterials reviewed the new advances in three-dimensional bioprinting (3DBP) for regenerative therapy in different organ systems.

Study:Advances in 3D bioprinting of tissues/organs for regenerative medicine and in-vitro models. Image Credit:luchschenF/Shutterstock.com

Organ/tissue shortage has emerged as a significant challenge in the medical field due to patient immune rejections and donor scarcity. Moreover, mimicking or predicting the human disease condition in the animal models is difficult during preclinical trials owing to the differences in the disease phenotype between animals and humans.

3DBP has gained significant attention as a highly-efficient multidisciplinary technology to fabricate 3D biological tissue with complex composition and architecture. This technology allows precise assembly and deposition of biomaterials with donor/patients cells, leading to the successful fabrication of organ/tissue-like structures, preclinical implants, and in vitro models.

In this study, researchers reviewed the 3DBP strategies currently used for regenerative therapy in eight organ systems, including urinary, respiratory, gastrointestinal, exocrine and endocrine, integumentary, skeletal, cardiovascular, and nervous systems. Researchers also focused on the application of 3DBP to fabricate in vitro models. The concept of in situ 3DBP was discussed.

In this extensively used low-cost bioprinting method, rotating screw gear or pressurized air is used without or with temperature to extrude a continuous stream of thermoplastic or semisolid material. Different materials can be printed at a high fabrication speed using this technology. However, low cell viability and the need for post-processing are the major drawbacks of extrusion bioprinting.

In this method, liquid drops are ejected on a substrate by acoustic or thermal forces. High fabrication speed, small droplet volume, and interconnected micro-porosity gradient in the fabricated 3D structures are the main advantages of this technique. However, limited printed materials and clogging are the biggest drawbacks of inkjet bioprinting.

A laser is used to induce the forward transfer of biomaterials on a solid surface in the laser-assisted bioprinting method. High cell viability and nozzle-free noncontact process are the biggest advantages of laser-assisted bioprinting, while metallic particle contamination and the time-consuming nature of the printing process are the major disadvantages.

Several studies were performed involving the development of neuronal tissues using the 3DBP method. The pressure extrusion/syringe extrusion (PE/SE) bioprinting technique was used for central nervous tissue (CNS) tissue replacement. The layered porous structure was fabricated using glial cells derived using human induced pluripotent stem cell (iPSC) and a novel bioink based on agarose, alginate, and carboxymethyl chitosan (CMC) formed synaptic networks and displayed a bicuculline-induced enhanced calcium response.

Similarly, stereolithography (SLA) was used to fabricate a 3D scaffold for CNS and the viability of the scaffold was evaluated for regenerative medicine application. Layered linear microchannels were printed using poly(ethylene glycol) diacrylate-gelatin methacrylate (PEGDA-GelMA) and rat E14 neural progenitor cells (NPCs). The 3D scaffold restored the synaptic contacts and significantly improved the functional outcomes. Cyclohexane was used to bond polystyrene fibers to matrix bundle terminals during crosslinking.

Multiphoton excited 3-dimensional printing (MPE-3DP) was employed for the regeneration of myocardial tissue. A layer-by-layer structure was fabricated using GelMA/ sodium 4-[2-(4-morpholino)benzoyl-2-dimethylamino]-butylbenzenesulfonate (MBS) and human hciPSC-derived cardiomyocytes (CMs), endothelial cells (ECs), and smooth muscle cells (SMCs). The crosslinking was performed by photoactivation. The structure promoted electromechanical coupling and improved cell proliferation, vascularity, and cardiac function.

Fused deposition modeling (FDM) and PE/SE bioprinting method were used for complex tissue and organ regeneration. A micro-fluid network heart shape structure was fabricated using polyvinyl alcohol (PVA), agarose, sodium alginate, and platelet-rich plasma and rat H9c2 cells and human umbilical vein endothelial cells (HUVECs). 2% calcium dichloride was used during the crosslinking mechanism. The fabricated structure possessed a valentine heart with hollow mechanical properties and a self-defined height.

SE printing was utilized to fabricate a capillary-like network using collagen type1/ xanthan gum and human fibroblasts and ECs for applications in blood vessels. The fabricated network possessed endothelial networks and sprouting between the fibroblast layers.

Bone, cartilage, and skeletal muscle tissue can be repaired and regenerated using the 3DBP technique. For instance, FDM printing was used to print multifunctional therapeutic scaffolds for the treatment of bone. Filopodial projections were fabricated using polylactic acid (PLA) platform loaded with hyaluronic acid (HA)/ iron oxide nanoparticles (IONS)/ minocycline and human MG-63 and human bone marrow stromal cells (hBMSCs), which improved the osteogenic stimulation of the IONS and HA.

PE/SE method was used to fabricate disks and cuboid-shaped scaffolds using - tricalcium phosphate (TCP) microgel and human fetal osteoblast (hFOB) and bone marrow-derived mesenchymal stem cell (BM-MSC) for bone repair, multicellular delivery, and disease model. The fabricated structures promoted osteogenesis.

PE/SE bioprinting was also utilized to fabricate complex porous layered cartilage-like structures using alginate/gelatin/HA, rat bone marrow mesenchymal stem cells (BMSCs), and cow cardiac progenitor cells (CPCs) for hyaline cartilage regeneration. The CPCs upregulated gene expression of proteoglycan 4 (PRG4), SRY-box transcription factor 9 (SOX9), and collagen II.

PE/SE printing was also used to fabricate multinucleated, highly-aligned myotube structures using polyurethane (PU), poly(-caprolactone) (PCL), and mouse C2C12 myoblasts and NIH/3T3 fibroblasts for in-situ expansion and differentiation of skeletal muscle tendon. The fabricated constructs demonstrated more than 80% cell viability with initial tissue differentiation and development.

SLA bioprinting technique was used to fabricate bi-layered epidermis-like structure using collagen type I, mouse NIH 3T3 fibroblast cells, and human keratinocyte cells for tissue model and engineering. The fabricated constructs effectively imitated the tissue functions.

Similarly, PE was employed to fabricate microporous structures using human amniotic mesenchymal stem cells (AFSCs) and heparin-HA-PEGDA for wound healing. The construct improved the wound closure and reepithelialization, increased extracellular matrix synthesis and vascularization, and prolonged the cell paracrine activity.

PE technique was utilized to prepare a multilayered cornea-like structure using human keratocytes and methacrylated collagen (ColMA)-alginate. The cell viability of the keratocytes decreased from 90% to 83% after printing.

PE/SE bioprinting was utilized to bioprint multilayered liver-like structures using GeIMA and human HepG2/C3A for liver tissue engineering. Similarly, hepatocytes were also bioprinted to fabricate multiple organ precursors with branching vasculature. A small intestine model with improved intestinal function and high cell proliferation was fabricated using caco-2 cell-loaded polyethylene vinyl acetate (PEVA) scaffold.

Spheroids of mesenchymal stem cells (MSCs) and chondrocytes and lung endothelial cells were utilized to fabricate scaffold-free tracheal transplant. After implantation in the rat model, the matured spheroids displayed excellent vasculogenesis, chondrogenesis, and mechanical strength. FDM technique was used to fabricate a glomerular structure for kidneys using human iPSCs and hydrogel and a hollow porous network using poly(lactic-co-glycolic acid (PLGA)/PCL/tumor-associated endothelial cells (TECs) for the urethra.

In in-situ bioprinting, the tissue is directly printed on the specific defect or wound site in the body for regenerative and reparative therapy. This method provides a well-defined structure and reduces the gap between host-implant interfaces. In-situ bioprinting is better than in vitro bioprinting techniques as the patients body, as a natural bioreactor, provides a natural microenvironment.

Several studies have evaluated this technique for tissue regeneration. For instance, PE/SE method was used for skin tissue regeneration in pigs and mice using fibrin/collagen/HA and human fibroblast cells. Skin-laden sheets of consistent composition, thickness, and width were formed upon rapid crosslinking of biomaterial. PE/SE technique was also used for neural tissue regeneration in mice using agarose/CMC/alginate and human iPSCs.

In vitro models provide significant assistance in understanding the mechanism of therapeutics and disease pathophysiology. Recently, in vitro models of human tissues and organs were engineered using 3DBP technology for safety assessment and drug testing.

In the 3DBP of organs and tissues, biomaterials play a crucial role in maintaining cellular viability, providing support, and long-term acceptance. Specifically, bioinks must possess unique properties, such as cell growth promotion and structural stability, that can be optimized for clinical use. Additionally, bioinks must be compatible with printers for high-precision rapid prototyping.

Bioinks fulfilling all of these requirements are yet to be identified. Moreover, managing the time during the bioprinting of the constructs is another major challenge, as the time required to fabricate them is often more than the survival time of cells. A bioreactor platform that supports organoid growth and provides time for tissue remodeling can be used to overcome this challenge. Ethical challenges and issues are also a hurdle since fabricating internal tissues/organs can lead to liability and biosafety concerns.

In the future, 3DBP can provide novel solutions to engineer organs/tissues and revolutionize modern healthcare and medicine if these challenges can be addressed.

More from AZoM: Building Durable and Sustainable Futures with [emailprotected]

Jain, P., Kathuria, H., Dubey, N. Advances in 3D bioprinting of tissues/organs for regenerative medicine and in-vitro models. Biomaterials 2022. https://www.sciencedirect.com/science/article/abs/pii/S0142961222002794?via%3Dihub

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

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What New Advances are there in 3D Bioprinting Tissues? - AZoM

Since their first successful derivation in 1998, human embryonic stem cells have received almost unprecedented attention. Hailed as the next revolution for medicine, they have been described as the future of molecular biology and the biggest development since recombinant DNA.1 It has been predicted that their successful derivation will have a more profound impact on health than even the advent of anaesthesia and the development of antibiotics.2 They are set to create a whole new genre of medical therapies.3 Their potential availability has also, however, opened a Pandoras box of ethical dilemmas, ranging from ongoing issues surrounding the moral status of the human embryo to the conflicting claims of alternative stem cell sources. Although integral to ethical discourse, these dilemmas demand understanding and assessment on scientific grounds. It is our contention that the ethical debate is being hindered by failure to appreciate the subtleties of the scientific background.

Since the ethical problems accompanying destruction of human embryos are well recognised, the advantages of bypassing these by employing adult stem cells are obvious. For many, the ethical conflicts would be avoided, while all the potential benefits to patients with severe diseases would be retained. Consequently, perceived ethical problems would be resolved if it could be demonstrated that adult stem cells are superior to embryonic stem cells as therapeutic agents.

Unfortunately, resolution is far from clear, for this research field is in its infancy. Scientific uncertainty abounds, and yet societies are demanding definitive scientific answers on stem cell technology. Since the least controversial course of action would be to use adult stem cells, the pressures on scientists to emerge with evidence demonstrating that their potential is equal to, or even greater than, that of embryonic stem cells are formidable. Scientific data and interpretation have become integral to the ethical debate, perhaps in inappropriate ways.

An understanding of the most fundamental aspects of stem cell identity and function is required, from the identification of stem cells to the role of environmental factors at both the microscopic and macroscopic levels. Recognising the role of environmental factors has ramifications both clinically and ethically. Acknowledgement of these factors will provide for greater understanding of the obstacles that have to be overcome if the clinical potential of stem cells is to be realised. It will also help clarify the notions of totipotency and pluripotency, concepts central to delineating the moral value of embryonic stem cells and their parent blastocysts.

Stem cells are unspecialised cells, which have the ability to renew themselves indefinitely, and under appropriate conditions can give rise to a variety of mature cell types in the human body. Some stem cells can give rise to a wide range of mature cell types, whereas others give rise to only a few. Stem cells can be derived from a variety of sources including early embryos, fetal tissue, and some adult tissues, of which bone marrow and blood are the best known examples. Hence, there are two populations of stem cells: embryonic and adult stem cells. Of these, embryonic stem cells are derived from the inner cell mass (ICM) of the blastocyst at five to seven days after fertilisation. At this point the blastocyst has differentiated into two cell types, ICM cells (some of which will give rise to the future individual) and the surrounding trophectoderm cells (which will later form the placenta).

The distinction between embryonic and adult stem cells raises the issue of accurate identification, a prerequisite to testing the claims frequently made for the abilities of both embryonic and adult stem cells to produce a wide array of cell and tissue types. Scientifically, the problem is a fundamental one: defining stem cells solely on the basis of their structurethat is, the specific markers they carry on their outer surfaces, is inaccurate and potentially misleading. Identification mayfor example, be complicated by some stem cells expressing markers from several kinds of lineages and may be further confused by the possibility that marker expression changes throughout development.4,5 The potential for misidentification is of considerable importance for the scientific community, which has called for functional as well as structural testing.

Placing far more reliance on the functional properties of stem cells opens up a wider debate, namely, the role of the environment in an understanding of stem cell function. The ability of the structure of stem cells to change points to the existence of a dynamic relationship between stem cells and their immediate microenvironment, the stem cell niche.

The niche concept was first developed in blood cells, where proliferation, differentiation, and survival of distinct progenitor populations were found to be dependent on factors secreted by other cell types.6 This microenvironment is characterised by numerous external signals, including those derived from chemical factors, cell/cell interactions, and relationships between cells and the surrounding tissue.6 These, in their various ways, all have an impact on stem cells, affecting the precise directions in which they subsequently develop.

This microenvironment is governed by regulatory mechanisms, the molecular nature of which is complicated and elusive. Schuldiner et al,7 in their study of the effects of eight growth factors on the capacity of human embryonic stem cells to form other cell types, found that while these factors altered developmental outcome, they did not produce uniform differentiation of the stem cells. Consequently, although the structural markers and functions of stem cells appear to be dependent upon their environment, defining the nature of this environment will be far from straightforward.

An increasing awareness of the role of the niche on stem cell structure and function has led to an evolving concept of the stem cell. For instance, there is now the suggestion that stem cells should be viewed, not as undifferentiated cells, but as appropriately differentiated cells with the potential to display diverse cell types in alternative niches.8 An excellent illustration of this point is provided in a recent study by Wu et al9 where human neural stem cells were primed in a cocktail of chemical factors and then implanted into various regions of the adult rat brain. Not only did the implanted stem cells give rise to a larger number of neurons than previously reported, but most significantly they gave rise to different neuronal types depending upon the region of the brain into which they were grafted. It is possible that the distinctive nature of the local environment in each brain region instructed the neural stem cells to adopt such different fates.

Furthermore, stem cells taken out of their original niche and exposed to an entirely new environment can potentially differentiate into the cell type(s) typical of that new environment. Human neural stem cellsfor example, produced muscle cells when introduced into skeletal muscle10 and human bone marrow cells differentiated into neural cells when transplanted into a neural environment.11 The above two studies were carried out in rodents, but more recently Mezey et al12 have demonstrated that a similar scenario is possible in humans. Following bone marrow transplants in patients with various forms of cancer, bone marrow stem cells entered the brain and generated neural cell types including neurons. In many of these studies, where stem cells have been transformed into cells from different lineages, there has been some form of injury to the stem cells new environment or niche. In light of this, it is possible that various factors, signals, or chemicals normally present in damaged or disrupted tissue may play a role in governing stem cell fate.

The above findings reflect the increasing influence being attributed to environmental factors, acknowledgement of which has led to the view that stem cells are dynamic rather than static entities. This view underpins the concept of stem cell plasticity, whereby stem cells from adult sources have the ability to dedifferentiate or redifferentiate into cells from other lineages. This may blur the absolute distinction so frequently made between embryonic and adult stem cells (let alone between specific types of adult stem cells), a determinative factor in much ethical debate.

Adult stem cells include stem cells from bone marrow, blood, fat, and both fetal and adult organs. Plasticity is particularly characteristic of bone marrow. Stem cells from this source can differentiate into neural cells,11,1315 (see above for further discussion) while other research has indicated that such cells can be incorporated into skeletal muscle.16

While these reports indicate that interest in the potential of adult stem cells is justified, they should be interpreted cautiously. It would be unwise to jump to the conclusion that these studies render the use of embryonic stem cells (with destruction of human embryos) unnecessary. There are a number of reasons for this.

First, accurate identification is a prerequisite for determining the presence and extent of plasticity. For instance, although Jackson et al17 presented data to suggest that a group of muscle cells could turn into blood cells, they later found they were dealing with a subpopulation of cells that normally reside in muscle tissue.18 What is required are more rigorous standards for determining stem cell plasticity.1921 Iffor example, cardiac cells developed from stem cells are to contribute to heart function, they would have to demonstrate synchronous contraction within the heart itself. Similarly, neural cells derived from neural stem cells would have to generate electrical impulses and release and respond to chemicals normally found within the brain.19,20

A second issue concerns frequency of occurrence. Failure to replicate previous experimental work showing that blood cells are capable of differentiating into neural cells, suggests that, if transformations are occurring, they are very rare.22 Consistent with this conclusion is the work of Jackson et al,23 who demonstrated plasticity in human blood stem cells, although the change to the desired heart and blood vessel cells occurred in only 0.02% of cells. Thus, as Winston24 notes, even in apparently rich sources, the cells capable of change may be very few in number, and this may ultimately diminish their therapeutic value.

A third point of concern with clinical applications in mind, is that transformations may occur via hybrid cells, that is, by the fusion of two distinct cell types. Such spontaneous fusion was observed when embryonic stem cells were grown in the laboratory in the presence of neural cells25 or bone marrow cells.26 Such hybrids, however, show chromosomal abnormalities that may preclude them from being used in therapeutic applications.

The apparent formation of such hybrid cells may have important implications for interpretations of stem cell plasticity. Such a phenomenon presents an alternate explanation for the claims that stem cells from one tissue type are able to produce the progeny of another tissue typethat is, bone marrow into muscle, blood into brain, and vice versa. In other words, adult stem cells may not be as plastic as early reports have suggested. Thus, as pointed out by Ying et al25 future stem cell plasticity studies should ensure that any transformed cells are examined and tested to see if they display properties of both the original and the introduced cell types.

A final note of caution is that it has become clear that there is far more data to show that embryonic stem cells are capable of indefinite growth and pluripotency than adult stem cells. Mouse embryonic stem cellsfor example, have been renewing for 10 years,27 a capacity yet to be demonstrated in cells from adult sources. If adult cells have a restricted renewal potential, this will have negative implications for therapeutic applications, which rely on the ability to expand cells accurately in the laboratory in order to provide enough material for effective transplantation. Furthermore, embryonic stem cells exhibit high levels of the enzyme telomerase which indicates their immortality,28 whereas adult stem cells grown in the laboratory do not exhibit this in the same way. This property renders embryonic stem cells important in the study of cellular ageing and stem cell renewal. Work with neural stem cells from biopsies and autopsies suggests that embryonic stem cells may be easier to coax into specific cell types than adult stem cells.18

Overall, there are few confirmed reports of truly pluripotential adult human stem cells,3,29 while even apparently convincing reports30 may raise serious queries when assessed in a critical manner.3 Nearly a dozen teams have reported adult stem cell plasticity31 and it seems unlikely that random mutation or hybrid fusion can explain all these results. What is required is far more understanding of the fundamental biological issues raised by this research. Even as Winston24 outlines the advantages of embryonic stem cell researchfor example, he recognises the benefits of adult stem cells in regard to safety, possible efficacy, and accessibility. Adult sources have the added advantage of not requiring an intermediate embryo for immunocompatibility. Similarly, while the UK Department of Health32 argues that the therapeutic potential of embryonic stem cells outweighs that of adult stem cells, it acknowledges that in the long term both may be useful. The UK government reiterated this point in 2002 by stating that it wishes to advance research with stem cells from all sources.33

Scientifically, therefore, research with both adult and embryonic sources should continue, although caution should be exercised in evaluating the results. Currently, however, adult stem cells are more problematic than their embryonic counterparts. In light of this evaluation, considerable care should be employed in advocating on allegedly scientific grounds, the advantages of adult over embryonic cells as the source of replacement tissues. The impetus behind such a sentiment stems principally from a desire to protect the status of the human embryo than from any demonstrated superiority of adult stem cell sources.14,34

Confusion at this point will do nothing to advance the cause of ethical analysis, since the current state of the science and its likely future directions are integral to serious ethical assessment. In other words, it is short sighted to attempt to circumvent discussion of the moral status of the blastocyst by concentrating on the potential of adult stem cells alone. Until it is accepted that this latter approach is a cul de sac for ethical discourse, the imperatives of some ethicists will continue to come into conflict with current scientific perspectives.

It is generally asserted that totipotency denotes the ability of a cell or group of cells to give rise to a complete individual, whereas pluripotency refers to the capacity to give rise to all the cell types constituting the individualbut not the individual as a whole. Helpful as this distinction is, it is limited, in that it neither acknowledges nor emphasises the importance of environmental influences in defining these abilities.

As we have seen, embryonic stem cells are derived from the ICM of the blastocyst. These ICM cells have the capacity to form all three embryonic germ layers: endoderm, which will form the lungs, liver, and gut lining; mesoderm, which will form the bone, blood, and muscle, and ectoderm, which will form the skin, eyes, and nervous system. Outwardly, these cells appear to give rise to a complete individual and are considered by some to be totipotent.35

The claim of totipotency requires a number of conditions, however, whether this be for blastocysts or embryonic stem cells. The latter must be undifferentiated and, hence, capable of giving rise to all three germ layers, a condition that is met when embryonic stem cells are derived from the ICM of the blastocyst. In addition, there is a requirement for trophectoderm cells, which will eventually form the layers of the placenta. The extraembryonic tissues are a crucial source of signalling molecules and must function optimally for the differentiation of both embryonic somatic cells and for the establishment of germlines.36 Since both trophectoderm and ICM cells are required for successful development of the fetus, both cell types are required to establish totipotency.37 Thus, totipotency becomes a function of the immediate environment of the embryonic stem cell. If a viable fetus is to result, totipotency also requires successful implantation and development within the uterus of a woman.

In the absence of all these conditions embryonic stem cells are only pluripotent, since they are capable of creating all the cell lines of the fetus, but not the fetus itself. In the laboratory environment they are incapable of totipotency, since they have been removed from the context of the trophectoderm, let alone that of the uterus. It is inaccurate, therefore, to refer to embryonic stem cells as totipotent rather than pluripotent.38

These criteria for establishing totipotency also have ramifications for the ethical evaluation of the human blastocyst. While the blastocyst has intact trophectoderm cells and, therefore, the capacity to produce all three germ layers, plus the extraembryonic material necessary for its survival, totipotency is still dependent on the wider environmentsuccessful implantation in a uterus. Hence, blastocysts within the laboratory are only potentially totipotent, in contrast to their counterparts within the body.

A blastocyst or even a later embryo in the laboratory lacks the capacity to develop into a human individual. Unfortunately, this simple observation is frequently overlooked, and moral discussion focuses on the potential of an embryo to grow into a fully developed human without any reference to its context. Ignoring context in this manner inevitably overlooks the crucial importance of an appropriate environment necessary for the realisation of totipotency, changes to which may also alter the moral debate. Just as stem cell identity and arguably moral value depend upon the microenvironment, so too the human embryo is intimately dependent upon its wider environment.

Much opposition to the use of embryonic stem cells relies upon the argument that adult stem cells could serve as a viable source of tissues for regeneration and therapy. In the light of this, the argument continues that embryonic stem cells, with their debatable ethical credentials, should no longer feature in attempts to produce replacement tissues. This stance uses alleged scientific evidence to bolster an ethical position, and stands or falls on the strength of the scientific case.

Apart from the validity or otherwise of this approach, definitive evidence will not be forthcoming for some time (possibly years), since the scientific issues are complex on-going ones. As outlined above, the potential of adult stem cells remains a matter for debate and further experimentation. Additionally, the dynamic nature of stem cells, both embryonic and adult, points to a close interrelationship between their potential and the environment in which they are located. The possibility of cell lineage change also has to be taken into account when the suitability of different stem cell types is being advocated. From a scientific perspective none of this is surprising, and yet it fits uneasily alongside any stance that is a mixture of scientific, ethical, and political rhetoric.

The necessity of paying attention to the scientific framework of the debate, such as we are doing, has implications for other stances as well. With the advance of scientific understanding and, specifically, the advent of a genetic level of understanding, has come a tendency to view the life of an individual on the basis of DNA alone. This too, however, ignores the dependence of the embryo upon a competent environment. The context within which the embryo develops, like the niche for the stem cell, is integral to all aspects of its functioning. The environment provides nutritional requirements as well as numerous cues to ensure the healthy development of the embryo and subsequent fetus. Consequently, the preservation of DNA cannot be equated with the preservation of an individuals life, as has been suggested by McGee and Caplan.39 Adherence to such a reductionist mode of thinking is only made possible by ignoring completely the contribution of the environment. Essential as DNA is for development, it requires an appropriate context if its potential is to be realised.

From this it follows that a notion such as totipotency is a function of the environment both at the microscopic and macroscopic levels. This suggests that ethical debate cannot be reduced to potential for life, since inherent within the potential of an embryo is an assumption regarding the appropriateness of its environment. This means that the context of blastocysts and later embryos is crucial, ethically as well as scientifically and clinically.

In light of this, it is appropriate to ask whether it is useful to continue thinking of the blastocyst as an independent entity with a moral status stemming entirely from its organisation and perceived potential. We have argued that neither blastocysts nor stem cells are to be viewed in isolation from their context. Given that the claim is frequently made that moral value and status are closely associated with embryonic potential, recognition of the importance of the environment will have major implications for ethical thinking.

Butler D . France opens door to use of embryos in stem cell research. Nature2000;408:629.

Okarma TB. Human primordial stem cells. Hastings Cent Rep1999;29:30.

Committee on the Biological and Biomedical Applications of Stem Cell Research. Stem cells and the future of regenerative medicine. Washington DC: National Academy Press, 2002.

Vogel G . Cell biology. Stem cells: new excitement, persistent questions. Science2000;290:16724.

Matsuoka SY, Ebihara Y, Xu M, et al. CD34 expression on long term repopulating hematopoietic stem cells changes during developmental stages. Blood2001;97:41925.

Watt FM, Hogan BL. Out of Eden: stem cells and their niches. Science2000;287:142730.

Schuldiner MO, Yanuka O, Itskovitz-Eldor J, et al. From the cover: effects of eight growth factors on the differentiation of cells derived from human embryonic stem cells. Proc Natl Acad Sci USA2000;97:1130712.

Van der Kooy D , Weiss S. Why stem cells? Science2000;287:143941.

Wu P , Tarasenko YI, Gu Y, et al. Region specific generation of cholinergic neurons from fetal human neural stem cells grafted in adult rat. Nat Neurosci2002;5:12718.

Galli R , Borello U, Gritti A, et al. Skeletal myogenic potential of human and mouse neural stem cells. Nat Neurosci2000;3:98691.

Zhao LR, Duan WM, Reyes M, et al. Human bone marrow stem cells exhibit neural phenotypes and ameliorate neurological deficits after grafting into the ischemic brain of rats. Exp Neurol2002;174:1120.

Mezey E , Key S, Vogelsang G, et al. Transplanted bone marrow generates new neurons in human brains. Proc Natl Acad Sci USA2003;100:13649.

Brazelton TR, Rossi FM, Keshet GI, et al. From marrow to brain: expression of neuronal phenotypes in adult mice. Science2000;290:17759.

Kopen GC, Prockop DJ, Phinney DG. Marrow stromal cells migrate throughout forebrain and cerebellum, and they differentiate into astrocytes after injection into neonatal mouse brains. Proc Natl Acad Sci USA1999;96:107116.

Meyer JR. Human embryonic stem cells and respect for life. J Med Ethics2000;26:16670.

Ferrari G , Cusella-De Angelis G, Coletta M, et al. Muscle regeneration by bone marrow derived myogenic progenitors. Science1998;279:152830.

Jackson KA, Mi T, Goodell MA. Hematopoietic potential of stem cells isolated from murine skeletal muscle. Proc Natl Acad Sci USA1999;96:144826.

Vastag B . Many say adult stem cell reports overplayed. JAMA2001;286:293.

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Blau HM, Brazelton TR, Weimann JM. The evolving concept of a stem cell: entity or function? Cell2001;105:82941.

DAmour KA, Gage FH. Are somatic stem cells pluripotent or lineage restricted? Nat Med2002;8:21314.

Morshead CM, Benveniste P, Iscove NN, et al. Hematopoietic competence is a rare property of neural stem cells that may depend on genetic and epigenetic alterations. Nat Med2002;8:26873.

Jackson KA, Majka SM, Wang H, et al. Regeneration of ischemic cardiac muscle and vascular endothelium by adult stem cells. J Clin Invest2001;107:1395402.

Winston R . Embryonic stem cell research. The case for. Nat Med2001;7:3967.

Ying QL, Nichols J, Evans EP, et al. Changing potency by spontaneous fusion. Nature2002;416:5458.

Terada N , Hamazaki T, Oka M, et al.Nature2002;416:5425.

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Zuk PA, Zhu M, Mizuno H, et al. Multilineage cells from human adipose tissue: implications for cell based therapies. Tissue Eng2001;7:21128.

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Stem cells, embryos, and the environment: a context for both science ...

The last decade of immunotherapy progress was based on decades of prior research, including other forms of immunotherapy.

Until recent years, cancer treatment revolved around surgery, chemotherapy, and radiation. But the FDA approval of ipilimumab (Yervoy) in 2011 led to a fourth leg of that treatment stool: immunotherapy. This enabled new treatment paradigms, sometimes with shocking levels of success.

The types of immunotherapy treatments available are proliferating, with approved immune checkpoint inhibitors (ICIs) and cellular therapies like chimeric antigen receptor (CAR) T cells as well as other modalities in the research and discovery phases. Some even include more established approaches like vaccines that are being revisited with new information and iterations.

The last decade of immunotherapy progress was based on decades of prior research, including other forms of immunotherapy. The Bacillus Calmette-Gurin vaccine, used to prevent tuberculosis for a century, has also been used as an immunotherapy to treat nonmuscle invasive bladder cancer since 1990.1 And rituximab (Rituxan), a monoclonal antibody therapy approved in 1997 for B-cell malignancies, is seen by some as an early immunotherapy as well.2

What many clinicians think of in terms of immunotherapy, however, are treatments targeting CTLA-4 and PD-1/PD-L1 pathways, brought from the bench by James P. Allison, PhD, and Tasuku Honjo, PhD, respectively, leading to a Nobel Prize awarded jointly to them in 2018.3

Immune responses are tightly controlled by T cells, and these T cells have on/off switches that help control their responses, according to Padmanee Sharma, MD, PhD, a professor in the Department of Genitourinary Medical Oncology in the Division of Cancer Medicine and the scientific director of the James P. Allison Institute at The University of Texas MD Anderson Cancer Center in Houston. Previously, she said, clinicians were not aware of the off switches. Sharma showed that CTLA-4 was an inhibitory pathway and that by blocking it, the T cells could stay longer to eradicate the tumors.

With 8 ICIs approved for immunotherapy in hematological and solid tumors,4 researchers are not only investigating newer forms of therapy, but also combining them to fi nd more effective and durable treatments and introducing them into earlier lines of treatment (TIMELINE). Current research is also attempting to predict who will respond to which therapy based on current and emerging biomarkers.

Ipilimumab, which kicked off the current era of cancer immunotherapy treatment with FDA approval in 2011, targets CTLA-4 for newly diagnosed or previously treated unresectable or metastatic melanoma.5 Ipilimumab blocks CTLA-4, removing its inhibitory signals. This allows the T cells to activate and launch an immune response to the tumors antigens.

CTLA-4 is basically the fi rst inhibitory pathway that comes up on the T cells, Sharma said. CTLA-4 is a member of an immunoglobulin-related receptor family responsible for some immune regulation aspects of T cells.6 It is thought to regulate T-cell proliferation mostly in lymph nodes, early in an immune response, by having an inhibitory role.7

What ipilimumab really did and what the immune checkpoint inhibitors really did is they opened up this whole different way to approach the immune system, Elizabeth Buchbinder, MD, a medical oncologist at Dana-Farber Cancer Institute and an assistant professor of medicine at Harvard Medical School in Boston, Massachusetts, said. Ipilimumab provided amazing durable responses in patients with melanoma with widely metastatic disease, some of whom were alive 10 years later, she said.

The PD-1 and PD-L1 blockades build on ipilimumabs success. Like CTLA-4, PD-1 is a negative regulator of T-cell immune function, inhibiting the target to increase immune system activation. PD-1 suppresses T cells mostly in the peripheral tissues.7 As of November 2021, 8 ICIs have been approved that target CTLA-4, PD-1, and PD-L1 pathways and treat 18 types of cancer.3

AntiPD-1 inhibitors

The percentage of people who benefi tted from ipilimumab was on the low side, Buchbinder said, with only an 11% response rate and 20% of people doing well long term in clinical trials. With PD-1 inhibition, however, there was approximately a 40% response rate and many more patients doing well long term, as demonstrated in clinical trials. So [PD-1 inhibition is] both far more effective and also less toxic, Buchbinder said.

When choosing an agent in the PD-1 class, we dont need to differentiate them. Theyre all antiPD-1, Sharma explained. There arent any data to indicate that patients will respond any differently to pembrolizumab [Keytruda] vs nivolumab [Opdivo]. The mechanism of action for both drugs [is] exactly the same.

Instead, clinicians should consider the FDA approvals for each drugs indications and combinations. But from a scientific standpoint, theres no distinguishing between [them], Sharma said.

AntiPD-L1 inhibitors

PD-1 and PD-L1 targeting drugs were found to work beyond melanoma and kidney cancer, the early indications for treatments targeting the CTLA-4 pathway, Buchbinder said. That was a huge opening up of this fi eld to all of these other cancers, like lung cancer, head and neck cancer, GI [gastrointestinal] cancer, breast [cancer], and beyond, she said.

Before receiving these immunotherapies, patients may need to show PD-1 or PD-L1 expression, although this may not identify all patients who can benefi t from the treatments. Researchers continue to try to identify additional and better biomarkers to indicate which patients may respond.13

In March, the FDA approved the newest ICI, nivolumab and relatlimab-rmbw (Opdualag), for adult and pediatric patients (12 years and older) with unresectable or metastatic melanoma. 3 Nivolumab is a PD-1 inhibitor, and relatlimab blocks LAG3 proteins on immune cells. It is being tested in a lot of other tumors, Buchbinder noted.

Another target in the discovery phase is T cell immunoglobulin and mucin domain 3, which is a checkpoint receptor expressed by many immune cells and leukemic stem cells.14 It is activated by several ligands and is being tested in different cancer types.

Also in clinical trials are tumor-infiltrating lymphocytes (TIL) that recognize cancer cells as abnormal, entering the tumor to kill the cells. TILs already recognize the targets because they originate from the tumor itself.15 Although they need to be expanded, they are not the same as CAR T cells, which must be engineered to recognize the targets.

In addition, older therapies are experiencing a resurgence, with research underway to make interleukin 2 (IL-2) help cytokines function better. That work is trying to optimize what those cytokines do in the body and the immune system, Buchbinder said. There are so many areas where the goal of the therapy is activation of the immune system.

One of these areas includes a return to vaccines. In earlier vaccine therapy, We had no idea that while we were giving therapy to turn on the cells, we were also rapidly turning off the cells because an on switch will automatically drive an off switch for the immune system, Sharma said. The yin and the yang of the immune response is very important to understand because when the immune response is driven in one direction, it will always try to control itself. With that in mind, newer vaccines might work better if given in combination with an antiCTLA-4, for example, to block the inhibitory pathways, she said.

Vaccines are taking many forms, including the mRNA vaccine used for COVID-19, peptide vaccines that include a tiny bit of protein that is expected to be expressed on the tumor surface, and vaccines constructed from dendritic cells, which stimulate T cells, Buchbinder said.

There are also viral therapies injected directly into tumor vaccines, such as talimogene laherparepvec (Imlygic) approved in 2015 for the treatment of some patients with metastatic melanoma that cannot be surgically removed.16 It is a is a modifi ed herpes virus directly injected into the tumor to bring about a local immune response, Buchbinder said.

According to Sharma, approximately 60 targets are currently being evaluated for immunotherapy development.

The FDA has approved 2 CAR T-cell therapies, both in 2017: tisagenlecleucel (Kymriah) for patients 25 years and younger with relapsed B-cell precursor acute lymphoblastic leukemia17 and axicabtagene ciloleucel (Yescarta) for the treatment of adult patients with large B-cell lymphoma that is refractory to fi rst-line chemoimmunotherapy or that relapses within 12 months of fi rst-line chemoimmunotherapy.18 These treatments involve collecting T cells from the patient and engineering them to express CARs that recognize the patients cancer cells. The cells are then enlarged and infused back into the patient, where they can target the antigen- expressing cancer cells. CARs have been shown to greatly improve clinical response and disease remission in some patients.19

I think CAR T cells are clearly building on the concept that T cells are the soldiers of immune response. They are basically engineering the cell to have an antibody that recognizes a specifi c antigen, Sharma said, adding that its important to ensure the targeted antigen is part of the cancer.

CAR T cells have had limited effectiveness in treating solid tumors, given the low T-cell infiltration and immunosuppressive environment that challenges the immune system from successfully reaching and killing solid tumor cancer cells.20

Natural killer (NK) cells are another cell type being researched to attempt tumor eradication, and this therapy is in the early stages, according to Sharma. CAR NK cells can be generated from allogenic donors, making them more attractive as off the shelf treatments compared with CAR T cells, which are collected from the patient. As of early 2021, more than 500 CAR T-cell trials and 17 CAR T-cell/NK-cell trials were in the works globally.21

A major consideration when choosing any treatment, including immunotherapies, is the adverse event (AE) profile. Immunotherapy drugs have different AEs than oncology treatments like chemotherapy or radiation. [With immunotherapy,] what we see is infl ammation because youre turning on the immune system in such a powerful way, Sharma said. Inflammatory reactions include a skin rash or dermatitis, infl ammation in the colon (colitis and diarrhea), and/or infl ammation in the lung with pneumonitis. Clinicians are now aware of these AEs and can monitor them closely, stopping therapy if needed to control them before they become severe, Sharma said.

Toxicities with ipilimumab can be severe, and patients requiring hospital admission might need high-dose steroids, Buchbinder noted. Common AEs for the CTLA-4 inhibitor are typically GI related, including diarrhea, colitis, and hepatitis. Some patients may experience fatigue or a small rash, but most generally make it through treatment with minimal AEs.

The stronger AEs with ipilimumab can be seen from a trial comparing ipilimumab plus nivolumab to nivolumab and relatlimab. Almost 60% of patients experienced AEs with the ipilimumab combination vs 20% in the latter group.17

PD-1 and PD-L1 inhibition typically involve AEs that cause lung issues rather than GI. The types of organ systems affected by immunotherapy AEs can vary based upon which checkpoint inhibitor you use but in some ways, the mechanism by which these occur is very similar, Buchbinder said. Its all an overactivation of the immune system leading to infl ammation in an organ, and there are very few organs that we have not seen toxicity from immunotherapy.

Buchbinder noted that cellular therapies can cause more severe AEs, such as cytokine release syndrome (CRS). Patients can get very sick very quickly, she said, because the therapies given with the cellsincluding the chemotherapy given before and the IL-2 given aftercause most of the AEs. With a lot of the injection therapies, the AEs are related to delivery method, like injection-site issues, but there are also potential systemic AEs like fever, chills, and reactions someone would get to a virus. Its really a huge range in terms of the different [adverse] effects, Buchbinder said.

CRS is the most common AE of CAR T-cell therapy, and it is caused by large numbers of T cells activating, which releases inflammatory cytokines. Although this demonstrates that the therapy is working, it can cause worrisome symptoms. The CRS and the related neurotoxicity can be treated with tocilizumab (Actemra).

One question in the immunotherapy world is whether the development of immune-related AEs predicts a positive or negative response to treatment. With melanoma, we think the data have been very tricky, Buchbinder said. Early trials appeared to show a higher response rate for patients who developed severe symptoms, but as trials developed, that signal was not always there. I think the overall impression is that yes, severe AEs are associated with a better response, she said. A cosmetic AE that clinicians who treat melanoma are excited to see, she said, is vitiligo. It suggests that the immune system is attacking normal melanocytes and that it is attacking cancer cells as well. Those patients generally do far better than patients who dont get vitiligo.

A meta-analysis of 30 studies on the topic, including 4971 individuals, showed that patients who developed immune-related AEs experienced an overall survival benefi t and a progression-free survival benefi t using ICI therapy compared with those who did not. The authors stated that more studies are needed and that the results are controversial.22

Melanoma has been the proving ground for ICIs, Buchbinder said, But now the bar is higher in terms of immunotherapy.

ICIs are now being tested in more immuneresistant tumors. Although there are huge hurdles in terms of some cancers where its going to be hard for immune therapy to do muchlike pancreatic cancer or prostate cancerthere are still diseases where theres opportunity and a possibility that the correct approach or combination might get to some great therapy for those diseases, Buchbinder said

Immunotherapies are being combined with conventional therapies to better integrate treatment. We dont see cancer as a death sentence anymore, Sharma said. We really do see a lot of hope, [and patients with cancer] should be encouraged to discuss immunotherapy with their physician either in a clinical trial or an FDA-approved agent. If you do have a response, its a pretty phenomenal response.

REFERENCES:

1. Lobo N, Brooks NA, Zlotta AR, et al. 100 years of Bacillus Calmette- Gurin immunotherapy: from cattle to COVID-19. Nat Rev Urol. 2021;18(10):611-622. doi:10.1038/s41585-021-00481-1

2. Pierpont TM, Limper CB, Richards KL. Past, present, and future of rituximab-the worlds fi rst oncology monoclonal antibody therapy. Front Oncol. 2018;8:163. doi:10.3389/fonc.2018.00163

3. Kruger S, Ilmer M, Kobold S, et al. Advances in cancer immunotherapy 2019 - latest trends. J Exp Clin Cancer Res. 2019;38(1):268. doi:10.1186/s13046-019-1266-0

4. Lee JB, Kim HR, Ha SJ. Immune checkpoint inhibitors in 10 years: contribution of basic research and clinical application in cancer immunotherapy. Immune Netw. 2022;22(1):e2. doi:10.4110/in.2022.22.e2

5. FDA approves Yervoy (ipilimumab) for the treatment of patients with newly diagnosed or previously-treated unresectable or metastatic melanoma, the deadliest form of skin cancer. News release. Bristol Myers Squibb. March 25, 2011. Accessed May 11, 2022. https://bit.ly/3PFp7q2

6. Rowshanravan B, Halliday N, Sansom DM. CTLA-4: a moving target in immunotherapy. Blood. 2018;131(1):58-67. doi:10.1182/ blood-2017-06-741033

7. Buchbinder EI, Desai A. CTLA-4 and PD-1 pathways: similarities, differences, and implications of their inhibition. Am J Clin Oncol. 2016;39(1):98-106. doi:10.1097/COC.0000000000000239

8. Keown A. Keytruda approvals: a timeline. BioSpace. Aug 13, 2019. Accessed May 11, 2022. https://bit.ly/3yHvfrL

9. Stewart J. Opdivo FDA approval history. Drugs.com. Updated March 15, 2022. Accessed May 20, 2022. https://bit.ly/3lnmtar

10. Markham A, Duggan S. Cemiplimab: fi rst global approval. Drugs. 2018;78(17):1841-1846. doi:10.1007/s40265-018-1012-5

11. FDA grants accelerated approval to dostarlimab-gxly for dMMr endometrial cancer. FDA. Updated April 22, 2021. Accessed May 20, 2022. https://bit.ly/38BSJns

12. Pierpont TM, Limper CB, Richards KL. Past, present, and future of rituximab-the worlds first oncology monoclonal antibody therapy. Front Oncol. 2018;8:163. doi:10.3389/fonc.2018.00163

13. Opdualag becomes fi rst FDA-approved immunotherapy to target LAG-3. National Cancer Institute. April 6, 2022. Accessed May 11, 2022. https://bit.ly/3FZWaAp

14. Acharya N, Sabatos-Peyton C, Anderson AC. TIM-3 finds its place in the cancer immunotherapy landscape. J Immunother Cancer. 2020;8(1):e000911. doi:10.1136/jitc-2020-000911

15. Boldt C. TIL Therapy: 6 things to know. MD Anderson Cancer Center. April 15, 2021. Accessed May 11, 2022. https://bit.ly/3wmguJb

16. FDA approves talimogene laherparepvec to treat metastatic melanoma. National Cancer Institute. November 25, 2015. Accessed May 20, 2022. https://bit.ly/3woTDwA

17. OLeary MC, Lu X, Huang Y, et al. FDA approval summary: tisagenlecleucel for treatment of patients with relapsed or refractory B-cell precursor acute lymphoblastic leukemia. Clin Cancer Res. 2019;25(4):1142-1146. doi:10.1158/1078-0432.CCR-18-2035

18. FDA approves CAR-T cell therapy to treat adults with certain types of large B-cell lymphoma. News release. FDA. Oct. 18, 2017. Accessed May 11, 2022. https://bit.ly/3wpECL1

19. FDA approves fi rst CAR T-cell therapy the evolution of CAR T-cell therapy. Cell Culture Dish. October 24, 2017. Accessed May 10, 2022. https:// bit.ly/3LlDD2B

20. Albinger N, Hartmann J, Ullrich E. Current status and perspective of CAR-T and CAR-NK cell therapy trials in Germany. Gene Ther. 2021;28:513-527. doi:10.1038/s41434-021-00246-w

21. Ahmad A, Uddin S, Steinhoff M. CAR-T cell therapies: an overview of clinical studies supporting their approved use against acute lymphoblastic leukemia and large B-cell lymphomas. Int J Mol Sci. 2020;21(11):3906. doi:10.3390/ijms21113906

22. Zhou X, Yao Z, Yang H, Liang N, Zhang X, Zhang F. Are immune-related adverse events associated with the efficacy of immune checkpoint inhibitors in patients with cancer? a systematic review and meta-analysis. BMC Med. 2020;18(1):87. doi:10.1186/s12916-020-01549-2

Read more from the original source:
10 Years of Immunotherapy: Advances, Innovations, and Better Patient Outcomes - Targeted Oncology

Umoja Biopharma, Inc.

Partnership combines Umojas technologies in gene-edited iPSCs and immune differentiation for persistent anti-tumor activity with TreeFrog Therapeutics biomimetic platform for the mass-production of iPSC-derived cell therapies in large-scale bioreactors

Umoja Biopharma and TreeFrog Therapeutics Announce Collaboration to Address Current Challenges Facing Ex Vivo Allogeneic Therapies in Immuno-Oncology

Mass-production of human induced pluripotent stem cells in a 10L bioreactor using TreeFrog Therapeutics C-Stem technology. Photo credits: TreeFrog Therapeutics

SEATTLE and PESSAC, France, June 10, 2022 (GLOBE NEWSWIRE) -- Umoja Biopharma, Inc., an immuno-oncology company pioneering off-the-shelf, integrated therapeutics that reprogram immune cells to treat patients with solid and hematologic malignancies, and TreeFrog Therapeutics, a biotechnology company aimed at making safer, more efficient and more affordable cell therapies based on induced pluripotent stem cells (iPSCs), announced today that they have entered into a collaboration to evaluate Umojas iPSC platform within TreeFrogs C-Stem technology for scalable expansion and immune cell differentiation in bioreactors.

Together, the successful pairing of Umojas RACR engineered iPS cells and TreeFrogs C-Stem technology could overcome several challenges facing ex vivo allogeneic therapies, said Ryan Larson, Ph.D., Vice President and Head of Translational Science at Umoja. Two major industry-wide challenges include the ability to scale iPSC-based culture while maintaining cell health, quality, and efficient immune cell differentiation. TreeFrogs biomimetic C-Stem technology is the perfect complementary development platform for our RACR technology, a pairing which could result in controlled, efficient iPSC expansion and differentiation into immune cells, with improved yields and quality. In addition to enhancing the differentiation and yield of immune cells within the manufacturing process, our RACR system should bring therapeutic benefit to patients, allowing for safe in vivo engraftment and persistence of tumor-killing cells without requirements for toxic lymphodepleting chemotherapy.

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Umoja is developing an engineered iPSC platform that addressesmany challenges associated with ex vivo cell therapy manufacturing, including limited scalability and manufacturing complexity.Umojas iPSCs are engineered with a synthetic rapamycin-activated cytokine receptor (RACR) to drive differentiation to, and expansion of innate cytotoxic lymphoid cells, including but not limited to natural killer (NK) cells in the absence of exogenous cytokines and feeder cells. TreeFrogs proprietary C-Stem technology relies on the high-throughput encapsulation (>1,000 capsules/second) of hiPSCs within biomimetic alginate shells, which promote in vivo-like exponential growth and protect cells from external stress. In 2021, C-Stem was demonstrated to allow for unprecedented iPSC expansion in 10L bioreactors, while preserving stem cell quality. Also enabling direct in-capsule iPSC differentiation, C-Stem constitutes a scalable, end-to-end, and GMP-compatible manufacturing platform for iPSC-derived cell therapies.

Frdric Desdouits, Ph.D., Chief Executive Officer at TreeFrog added, Our primary goal is to bring the benefits of the C-Stem technology to patients as fast as possible, either through in-house programs or strategic alliances with cell therapy leaders. Partnering with Umoja is an important step forward in immuno-oncology. Besides scale-up and cell quality, the in vivo persistence of allogeneic therapies remains a critical challenge in the industry. We believe Umojas platform will allow for safer and more efficient allogeneic cell therapies in immuno-oncology. We look forward to rapidly advancing this joint approach to clinic and contributing to the future of off-the-shelf cancer treatments.

About Umoja BiopharmaUmoja Biopharma, Inc. is an early clinical-stage company advancing an entirely new approach to immunotherapy. Umoja Biopharma, Inc. is a transformative multi-platform immuno-oncology company founded with the goal of creating curative treatments for solid and hematological malignancies by reprogramming immune cells in vivo to target and fight cancer. Founded based on pioneering work performed at Seattle Childrens Research Institute and Purdue University, Umojas novel approach is powered by integrated cellular immunotherapy technologies including the VivoVec in vivo delivery platform, the RACR/CAR in vivo cell expansion/control platform, and the TumorTag targeting platform. Designed from the ground up to work together, these platforms are being developed to create and harness a powerful immune response in the body to directly, safely, and controllably attack cancer. Umoja believes that its approach can provide broader access to the most advanced immunotherapies and enable more patients to live better, fuller lives. To learn more, visithttp://umoja-biopharma.com/.

About TreeFrog TherapeuticsTreeFrog Therapeutics is a French-based biotech company aiming to unlock access to cell therapies for millions of patients. TreeFrog Therapeutics is developing a pipeline of therapeutic candidates using proprietary C-Stem technology, allowing for the mass production of induced pluripotent stem cells and their differentiation into ready-to-transplant microtissues with unprecedented scalability and cell quality. Bringing together over 80 biophysicists, cell biologists and bioproduction engineers, TreeFrog Therapeutics raised $82M over the past 3 years to advance its pipeline in regenerative medicine and immuno-oncology. The company is currently opening technological hubs in Boston, USA, and Kobe, Japan, to drive the adoption of C-Stem and build strategic alliances with leading academic, biotech and industry players in the field of cell therapy.

Umoja Biopharma Media Contact:Darren Opland, Ph.D.LifeSci Communicationsdarren@lifescicomms.com

TreeFrog Therapeutics Media Contact:Pierre-Emmanuel GaultierTreeFrog Therapeuticspierre@treefrog.fr

A photo accompanying this announcement is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/012ae87d-b7c6-4fa2-81dc-c769877b182c

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Umoja Biopharma and TreeFrog Therapeutics Announce Collaboration to Address Current Challenges Facing Ex Vivo Allogeneic Therapies in Immuno-Oncology...

From cities in the sky to robot butlers, futuristic visions fill the history ofPopSci. In theAre we there yet?column we check in on progress towards our most ambitious promises. Read the series and explore all our 150th anniversary coveragehere.

In 1923, Popular Science reported that people were drinking radium-infused water in an attempt to stay young. How far have we come to a real (and non-radioactive) cure for aging?

From the time Marie Curie and her husband Pierre discovered radium in 1898, it was quickly understood that the new element was no ordinary metal. When the Curies finally isolated pure radium from pitchblende (a mineral ore) in 1902, they determined that the substance was a million times more radioactive than uranium. At the time, uranium was already being used in medicine to X-ray bones and even treat cancer tumors, a procedure first attempted in 1899 by Tage Sjogren, a Swedish doctor. Coupled with radiums extraordinary radioactivity and unnatural blue glow, the mineral was soon touted as a cure for everything including cancer, blindness, and baldness, even though radioactivity had only been used to treat malignant tumors. As Popular Science reported in June 1923, it was even believed that a daily glassful of radium-infused water would restore youth and extend life, making it the latest in a long line of miraculous elixirs.

By May 1925 The New York Times was among the first to report cancer cases linked to radium. Two years later, five terminally ill women, who became known as the Radium Girls, sued the United States Radium Corporation where they had worked, hand-painting various objects with the companys poisonous pigment. As more evidence emerged of radiums carcinogenic effects, its cure-all reputation quickly faded, although it would take another half-century before the last of the luminous-paint processing plants was shut down. Radium is still used today in nuclear medicine to treat cancer patients, and in industrial radiography to X-ray building materials for structural defectsbut its baseless status as a life-extending elixir was short-lived.

And yet, radiums downfall did not end the true quest for immortality: Our yearning for eternal youth continues to inspire a staggering range of scientifically dubious products and services.

Since the early days of civilization, when Sumerians etched one of the first accounts of a mortal longing for eternal life in the Epic of Gilgamesh on cuneiform tablets, humans have sought a miracle cure to defy aging and defer death. Five thousand years ago in ancient Egypt, priests practiced corpse preservation so a persons spirit could live on in its mummified host. Fortunately, anti-aging biotech has advanced from mummification and medieval quests for the fountain of youth, philosophers stone, and holy grail, as well as the perverse practices of sipping metal-based elixirs, bathing in the blood of virgins, and even downing Radium-infused water in the early 20th century. But what hasnt changed is that the pursuit of eternal youth has largely been sponsored by humankinds wealthiest citizens, from Chinese emperors to Silicon Valley entrepreneurs.

Weve all long recognized that aging is the greatest risk factor for the overwhelming majority of chronic diseases, whether it be Alzheimers disease, cancer, osteoporosis, cardiovascular diseases, or diabetes, says Nathan LeBrasseur, co-director of The Paul F. Glenn Center for Biology of Aging Research at the Mayo Clinic in Minnesota. But weve really kind of said, well, theres nothing we can do about senescence [cellular aging], so lets move on to more prevalent risk factors that we think we can modify, like blood pressure or high lipids. In the last few decades, however, remarkable breakthroughs in aging research have kindled interest and opened the funding spigots. Fortunately, the latest efforts have been grounded in more established scienceand scientific methodsthan was available in radiums heyday.

In the late 19th century, just as scientists began zeroing in on germs with microscopes, evolutionary biologist August Weismann delivered a lecture on cellular aging, or senescence. The Duration of Life (1881) detailed his theory that cells had replication limits, which explained why the ability to heal diminished with age. It would take 80 years to confirm Weismanns theory. In 1961, biologists Leonard Hayflick and Paul Moorhead observed and documented the finite lifespan of human cells. Another three decades later, in 1993, Cynthia Kenyon, a geneticist and biochemistry professor at the University of California, San Francisco, discovered how a specific genetic mutation in worms could double their lifespans. Kenyons discovery gave new direction and hope to the search for eternal youth, and wealthy tech entrepreneurs were eager to fund the latest quest: figuring out how to halt aging at the cellular level. (Kenyon is now vice president of Calico Research Labs, an Alphabet subsidiary.)

Weve made such remarkable progress in understanding the fundamental biology of aging, says LeBrasseur. Were at a new era in science and medicine, of not just asking the question, what is it about aging that makes us at risk for all these conditions? But also is there something we can do about it? Can we intervene?

In modern aging research labs, like LeBrasseurs, the focus is to tease apart the molecular mechanisms of senescence and develop tools and techniques to identify and measure changes in cells. The ultimate goal is to discover how to halt or reverse the changes at a cellular level.

But the focus on the molecular mechanisms of aging is not new. In his 1940 book, Organisers and Genes, theoretical biologist Conrad Waddington offered a metaphor for a cells life cyclehow it grows from an embryonic state to something specific. In Waddingtons epigenetic landscape, a cell starts out in its unformed state at the top of a mountain with the potential to roll downhill in any direction. After encountering a series of forks, the cell lands in a valley, which represents the tissue it becomes, like a skin cell or a neuron. According to Waddington, epigenetics are the external mechanisms of inheritanceabove and beyond standard genetics, such as chemical or environmental factorsthat lead the cell to roll one way or another when it encounters a fork. Also according to Waddington, who first proposed the theory of epigenetics, once the cell lands in its valley, it will remain there until it diesso, once a skin cell, always a skin cell. Waddington viewed cellular aging as a one-way journey, which turns out to be not so accurate.

We know now that even cells of different types keep changing as they age, says Morgan Levine, who until recently led her own aging lab at the Yale School of Medicine, but is now a founding principal investigator at Altos Labs, a lavishly funded startup. The [Waddington] landscape keeps going. And the new exciting thing is reprogramming, which shows us that you can push the ball back the other way.

Researchers like Levine continue to discover new epigenetic mechanisms that can be used to not only determine a cells age (epigenetic or biological clock) but also challenge Waddingtons premise that a cells life is one way. Cellular reprogramming is an idea first attempted in the 1980s and later advanced by Nobel Prize recipient Shinya Yamanaka, who discovered how to revert mature, specialized cells back to their embryonic, or pluripotent, state, enabling them to start fresh and regrow, for instance, into new tissue like liver cells or teeth.

I like to think of the epigenome as the operating system of a cell, Levine explains. So more or less all the cells in your body have the same DNA or genome. But what makes the skin cell different from a brain cell is the epigenome. It tells a cell which part of the DNA it should use thats specific to it. In sum, all cells start out as embryonic or stem cells, but what determines a cells end state is the epigenome.

Theres been a ton of work done with cells in a dish, Levine adds, including taking skin cells from patients with Alzheimers disease, converting them back to stem cells, and then into neurons. For some cells, you dont always have to go back to the embryonic stem cell, you can just convert directly to a different cell type, Levine says. But she also notes that what works in a dish is vastly different from what works in living specimens. While scientists have experimented with reprogramming cells in vivo in lab animals with limited success, the ramifications are not well understood. The problem is when you push the cells back too far [in their life cycle], they dont know what theyre supposed to be, says Levine. And then they turn into all sorts of nasty things like teratoma tumors. Still, shes hopeful that many of the problems with reprogramming may be sorted out in the next decade. Levine doesnt envision people drinking cellular-reprogramming cocktails to stave off agingat least not in the foreseeable futurebut she does see early-adopter applications for high-risk patients who, lets say, can regrow their organs instead of requiring transplants.

While the quest for immortality is still funded largely by the richest of humans, it has morphed from the pursuit of mythical objects, miraculous elements, and mystical rituals to big business, raising billions to fund exploratory research. Besides Calico and Altos Labs (funded by Russian-born billionaire Yuri Milner and others), theres Life Biosciences, AgeX Therapeutics, Turn Biotechnologies, Unity Biotechnology, BioAge Labs, and many more, all founded in the last decade. While theres considerable hype for these experimental technologies, any actual products and services will have to be approved by regulatory agencies like the Food and Drug Administration, which did not exist when radium was being promoted as a cure-all in the US.

While were working on landing long-term moon shots like editing genomes with CRISPR and reprogramming epigenomes to halt or reverse aging, LeBrasseur sees near-term possibilities in repurposing existing drugs to prop up senescent cells. When a cell gets old and damaged, it has one of three choices: to succumb, in which case it gets flushed from the system; to repair itself because the damage is not so bad; or to stop replicating and hang around as a zombie cell. Not only do [zombie cells] not function properly, explains LeBrasseur, but they secrete a host of very toxic molecules known as senescence associated secretory phenotype, or SASP. Those toxic molecules trigger inflammation, the precursor to many diseases.

It turns out there are drugs, originally targeted at other diseases, that are already in anti-aging trials because theyve shown potential to impact cell biology at a fundamental level, effectively staving off senescence. Although rapamycin was originally designed to suppress the immune system in organ transplant patients, and metformin to assist diabetes patients, both have shown anti-aging promise. When you start looking at data from an epidemiological lens, you recognize that these individuals [like diabetes patients taking metformin] often have less cardiovascular disease, notes LeBrasseur. They also have lower incidence of cancer, and theres some evidence that they may even have lower incidence of Alzheimers disease. Even statins (for cardiovascular disease) and SGL2 inhibitors (another diabetes drug) are being explored for a possible role in anti-aging. Of course, senescence is not all bad. It plays an important role, for example, as a protective mechanism against the development of malignant tumorsso tampering with it could have its downsides. Biology is so smart that weve got to stay humble, right? says LeBrasseur.

Among other things, the Radium Girls taught us to avoid the hype and promise of new and unproven technologies before the pros and cons are well understood. Weve already waited millennia for a miracle elixir, making some horrific choices along the way, including drinking radioactive water as recently as a century ago. The 21st century offers its own share of anti-aging quackery, including unregulated cosmetics, questionable surgical procedures, and unproven dietary supplements. While we may be closer than weve ever been in human history to real solutions for the downsides of aging, there are still significant hurdles to overcome before we can reliably restore youth. It will take years or possibly decades of research, followed by extensive clinical trials, before todays anti-aging research pays dividendsand even then its not likely to come in the form of a cure-all cocktail capable of bestowing immortality. In the meantime, LeBrasseurs advice is simple for those who can afford it: You dont have to wait for a miracle cure. Lifestyle choices like physical activity, nutritional habits, and sleep play a powerful role on our trajectories of aging. You can be very proactive today about how well you age. Unfortunately, not everyone has the means to follow LeBrasseurs medical wisdom. But the wealthiest among usincluding those funding immortalitys questmost definitely do.

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Radium was once cast as an elixir of youth. Are todays ideas any better? - Popular Science

Stem Cells 101

Every cell type in the body that makes up organs and tissues arose from a more primitive cell type called a stem cell. Stem cells are the foundation of living organisms, with the unique ability to self-renew and differentiate into specialised cell types. There are three different types of stem cell, classified by the number of specialised cell types they can produce: i) pluripotent stem cells (e.g. embryonic stem cells) can generate any specialised cell type; ii) multipotent stem cells (e.g. mesenchymal stem cells) are able to generate multiple, but not all, specialised cell types; and, iii) unipotent stem cells (e.g. epidermal stem cells that produce skin) give rise to only one cell type. It was long believed that stem cell differentiation into specialised cell types only occurs in one direction. There have been many exciting advances in stem cell biology, most notable the discovery of induced pluripotent stem cells (iPSCs) that demonstrated a mature differentiated specialised cell can be reverted to a primitive pluripotent stem cell (Takahashi K, 2006). This discovery transformed our understanding of stem cell biology enabling exciting and substantial advances in stem cell tools, technologies and applications. This article focuses on pluripotent stem cells, as they offer the most promising future applications.

To harness the power of stem cells, they must first be maintained in vitro tissue culture. Culture expansion of stem cells is tricky because they must be maintained in an undifferentiated state and not permitted to differentiate into other cell types until desired. In short, if stem cells are not dividing in log phase growth, they are differentiating. Historically, pluripotent stem cells were notoriously difficult to work with in the lab largely because of the of inherent variability of reagents derived from animal tissues.

An important concept affecting current and future innovations in stem cell technologies is Good Manufacturing Practice (GMP). This is governed by formal regulations administered by drug regulatory agencies (for example the FDA) that control the manufacture processes of medicines. The use of stem cells as therapeutic agents has necessitated specialised drug regulations known as Advanced Therapeutic Medicinal Products (ATMPs). Unlike chemically synthesised medicines where the final product can be defined through chemical analysis, ATMPs are complex biological living entities whereby the entire manufacturing process defines the final product. In simple terms, every reagent that touches the stem cells in the manufacturing process throughout the entire lifetime of the stem cell becomes a component of the final product. As such, in the real world the quality and consistency of the reagents used in a stem cell manufacturing process is paramount for downstream clinical applications, even if the project is still in the R&D or preclinical phase. Once reserved for clinical applications, GMP has become a dominating concept that affects all aspects of stem cell research and applications. Researchers and clinical developers benefit alike from GMP-focused innovations in stem cell technologies that deliver consistent growth properties and high-quality results.

Significant advances that overcome the challenges of the past have been made in all aspects of in vitro stem cell culture. These include advances in tissue culture medium, extracellular matrix, 3D synthetic cell culture plastic, growth factors, dissociation enzymes, cryopreservation agents and differentiation technologies. The workflow to culture stem cells in vitro is not a linear process but rather a continuous circle that can be broken down into 6 steps: 1) Extracellular Matrix coating of tissue culture plasticware; 2) Revival/seeding of tissue culture flasks; 3) Expansion of the cell culture in an incubator; 4) Culture medium change; 5) Subculture or passaging one flask to many; and 6) Cryopreservation of the stem cell culture. The stem cell workflow is shown in Figure 1.

The art of culturing stem cells is a lot easier today than in the past. Stem cells grow as adherent cultures on the surface of tissue culture flasks or dishes (image shown in Figure 1, Step 3). For the stem cells to adhere to the surface it must be coated with extracellular matrix. In the early days, it was an effort to maintain stem cells in culture because the cultures needed to be grown on a feeder layer of fibroblast cells. The requirement for a second cell culture combined with the stem cell culture is laborious to set up and severely limited experiments and applications (due to the contaminating fibroblasts mixed with the stem cells). Extracellular matrix isolated from mouse tumours removed the need for feeder layer cultures but can be variable in consistency and contain contaminants. Today, researchers benefit from recombinantly expressed extracellular matrix containing laminin-511 fragments that provides highly efficient adherence of a broad range of cell types and is easy to use (with only 1 hour coating time required that saves time and cost). Exceptional pluripotent stem cell adherence is achieved with laminin-511 fragments. The recombinant extracellular matrix laminin-511 is expressed in mammalian cell culture (e.g. CHO cells) or insect culture (e.g. silkworm) that eliminates the need for animal derived products in the extracellular matrix. Alternatively, synthetic 3D plastic scaffolds (e.g. Alvetex) are also available that offer a rigid defined matrix that is non-biological.

Early stem cell culture media required the medium to be replenished daily. This means 7 days a week in the lab tending to the stem cell cultures. Optimisation of tissue culture medium composition enables cultures to be maintained over the weekend without a medium change, enabling feeder-free, weekend-free stem cell culture. This may sound insignificant but does have a huge impact on the lifestyle of researchers working with stem cells. Unlike early tissue culture media, the composition of the culture media are fully defined and contain no animal derived products. Removal of animal-derived products offers important advantages by removing variability inherent in animal-derived products and guaranteeing consistent cell growth. Furthermore, animal-free formulations eleminate the risk of infection arising from the animal product (e.g. TSE risk). Growth factors are a critical component of the culture medium to maintain the stem cells in an undifferentiated state. Products available on the market contain growth factors that are expressed and isolated from barley.

Stem cells undergo cellular division in the culture vessel. As they expand, they will eventually outgrow their home and must be subcultured to separate flasks to provide space for further growth. Common practice is to use a digestive enzyme to free the stem cells from the culture surface. Trypsin isolated from bovine is commonplace in the tissue culture laboratory. Advances in the products available today use trypsin expressed in maize that is stable at room temperature in solution. Collagenase is an alternative dissociation reagent that is gentle and efficient on a wide range of cells and is available both animal-free and GMP grade - again enabling robust consistent culture conditions, and removing the dependence on animal derived products that are inherently variable.

The stem cells harvested from cultures can be frozen and stored (or cryopreserved) safely for several decades. When required, the cryopreserved stem cells may be defrosted, revived and expanded in culture providing a renewable source of stem cells. During cryopreservation of stem cells, it is critical to prevent cell death and changes in genotype/phenotype. Todays cryopreservation media can maintain consistent high cell viability after thawing; maintaining cell pluripotency, normal karyotype and proliferation even after long term cell storage. Traditionally, the cryopreservation process involved a rate-controlled freezer or a specialised container to freeze the cells at -1C/min. Advances in cryopreservation agents have removed the need for rate-controlled freezing. The process is now simple - you just place the stem cell suspension into a -80C freezer. Moreover, cryopreservation agents are available in GMP grade and with no animal-derived ingredients.

The power of stem cells lies in their ability both to self-renew and to differentiate into specialised cell types. The process of differentiation removes the stem cells from the workflow towards applications. Directed differentiation of stem cells into specific cell types enables the number of applications to grow. A typical differentiation protocol uses stepwise changes in culture medium, cytokines, growth factors and extracellular matrix over several weeks to direct the stem cells into a particular lineage and fate. Today, innovative technologies use genetic reprogramming factors that rapidly (< 1 week) differentiate stem cells into mature cell phenotypes. This advance significantly reduces time to experiment and increases manufacturing capacity for differentiated cell types.

Table 1. Advances in Stem Cell Technologies.Description Area of Innovation Examples of Innovative ProductsExtracellular Matrix Recombinant Laminin Expressed in CHO and Silkworm iMatrix-511Culture Medium No medium change required over the weekend, GMP grade, animal free StemFit MediumGrowth Factors Recombinant, GMP grade, animal free StemFit PuroteinDissociation Reagents Trypsin enzyme recombinantly expressed in maize. Collagenase & Neutral Protease expressed in Clostridium histolyticum TrypLECollagenase NBNeutral Protease NBCryopreservation Rate-controlled freezing not required. GMP grade, animal free and available for clinical use. Suitable for all cell types. STEM-CELLBANKERDifferentiation Rapid directed differentiation through genetic reprogramming Quick-Skeletal MuscleQuick-EndotheliumQuick-Neuron

There are unlimited applications that arise from a renewable source of mature cell types. One exciting area of innovation using differentiated stem cells is in disease modelling. Studying a disease state in an organ or tissue has in the past been limited to using in vivo animal models; whereas, differentiated stem cells opened the opportunity to create disease states in specific cell types in vitro. In addition, current technologies enable organoids or mini organs to be generated in the laboratory. Disease specific induced pluripotent stem cells can also be used to create disease models in vitro that are valuable tools for the study of disease and drug development without the need for in vivo animal models. In theory, any tissue is possible to create in vitro. In an exciting example of stem cell disease modelling, Dr Takayama from the CiRA in Kyoto, Japan has successfully modelled the life cycle of SARS-CoV-2 in both organoids and undifferentiated pluripotent stem cells (Takayama, 2020) (Sano, 2021) (Figure 2). In another example, the Skeletal Muscle Differentiation Kit was used to produce skeletal muscle myotubes from stem cells to create an in vitro disease model (Figure 3). In a direct application, pluripotent stem cell models of skeletal muscle have also been successfully used to develop a novel treatment for Duchenne muscular dystrophy (Moretti, 2020).

Promising progress is being made to create meat in the laboratory or what is commonly called cultured meat. Environmental concerns are driving the need for more sustainable meat production over traditional farming methods. Stem cell research in itself is reducing the need for the use of animals across multiple aspects as highlighted here. Producing cultured meat is straightforward in principle but faces many challenges in practice, for example maintaining the correct environment and stimuli for cultured cells to produce meat with the correct consistency and characteristics of the animal derived product. Stem cell cultures are expanded at scale in bioreactors and differentiated into skeletal muscle cells. These can be structured, using an edible scaffold for example, or used unstructured as the raw material to produce meat products (Figure 4). Tools and technologies are readily available to achieve this goal: expansion and differentiation of stem cells is highly efficient. However, a key consideration is the cost of goods. Current technologies are too costly but these are pioneering times and research is moving at an exciting pace.

The promise and potential of stem technologies to advance biology, medicine and food production can only be fulfilled if stem cell culture conditions are consistent, and accessible to research scientists and commercial operations alike. Exciting advances across multiple aspects of the stem cell workflow have streamlined processes to deliver products that are fully defined and animal-free. Furthermore, clinical translation of stem cell therapies and drug discovery are accelerated by the availability of GMP compliant reagents. The foundations are set for a bright future of discoveries and applications emerging from stem cell technologies.

Dr William Hadlington-Booth is the business unit manager for stem cell technologies and the extracellular matrix at AMSBIO. Erik Miljan, PhD, is a pioneer in the development of cellular therapies for a range of degenerative and disease conditions. He holds a PhD in biochemistry from Hong Kong University. For further information please contact:William@amsbio.com

Moretti, A. F., et al. (2020). Somatic gene editing ameliorates skeletal and cardiac muscle failure in pig and human models of Duchenne muscular dystrophy. Nature Medicine, 26, 207214.Takahashi K., et al. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. . Cell, 126, 663-676.Takayama, K. (2020). In Vitro and Animal Models for SARS-CoV-2 research. Trends in Pharmacological Sciences, 41. 513-517.Sano, E., et al. (2021). Modeling SARS-CoV-2 infection and its individual differences with ACE2-expressing human iPS cells. Iscience, 24(5), 102428.

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Current and Future Innovations in Stem Cell Technologies - Labmate Online

"It actually changed my life," said Taylor, who directed regenerative medicine research at Texas Heart Institute in Houston until 2020. "I said to myself, 'Oh my gosh, that's life.' I wanted to figure out the how and why, and re-create that to save lives."

That goal has become reality. On Wednesday at the Life Itself conference, a health and wellness event presented in partnership with CNN, Taylor showed the audience the scaffolding of a pig's heart infused with human stem cells -- creating a viable, beating human heart the body will not reject. Why? Because it's made from that person's own tissues.

"Now we can truly imagine building a personalized human heart, taking heart transplants from an emergency procedure where you're so sick, to a planned procedure," Taylor told the audience.

"That reduces your risk by eliminating the need for (antirejection) drugs, by using your own cells to build that heart it reduces the cost ... and you aren't in the hospital as often so it improves your quality of life," she said.

Debuting on stage with her was BAB, a robot Taylor painstakingly taught to inject stem cells into the chambers of ghost hearts inside a sterile environment. As the audience at Life Itself watched BAB functioning in a sterile environment, Taylor showed videos of the pearly white mass called a "ghost heart" begin to pinken.

"It's the first shot at truly curing the number one killer of men, women and children worldwide -- heart disease. And then I want to make it available to everyone," said Taylor to audience applause.

"She never gave up," said Michael Golway, lead inventor of BAB and president and CEO of Advanced Solutions, which designs and creates platforms for building human tissues.

"At any point, Dr. Taylor could have easily said 'I'm done, this just isn't going to work. But she persisted for years, fighting setbacks to find the right type of cells in the right quantities and right conditions to enable those cells to be happy and grow."

Giving birth to a heart

"We were putting cells into damaged or scarred regions of the heart and hoping that would overcome the existing damage," she told CNN. "I started thinking: What if we could get rid of that bad environment and rebuild the house?"

Soon, she graduated to using pig's hearts, due to their anatomical similarity to human hearts.

"We took a pig's heart, and we washed out all the cells with a gentle baby shampoo," she said. "What was left was an extracellular matrix, a transparent framework we called the 'ghost heart.'

"Then we infused blood vessel cells and let them grow on the matrix for a couple of weeks," Taylor said. "That built a way to feed the cells we were going to add because we'd reestablished the blood vessels to the heart."

The next step was to begin injecting the immature stem cells into the different regions of the scaffold, "and then we had to teach the cells how to grow up."

"We must electrically stimulate them, like a pacemaker, but very gently at first, until they get stronger and stronger. First, cells in one spot will twitch, then cells in another spot twitch, but they aren't together," Taylor said. "Over time they start connecting to each other in the matrix and by about a month, they start beating together as a heart. And let me tell you, it's a 'wow' moment!"

But that's not the end of the "mothering" Taylor and her team had to do. Now she must nurture the emerging heart by giving it a blood pressure and teaching it to pump.

"We fill the heart chambers with artificial blood and let the heart cells squeeze against it. But we must help them with electrical pumps, or they will die," she explained.

The cells are also fed oxygen from artificial lungs. In the early days all of these steps had to be monitored and coordinated by hand 24 hours a day, 7 days a week, Taylor said.

"The heart has to eat every day, and until we built the pieces that made it possible to electronically monitor the hearts someone had to do it person -- and it didn't matter if it was Christmas or New Year's Day or your birthday," she said. "It's taken extraordinary groups of people who have worked with me over the years to make this happen."

But once Taylor and her team saw the results of their parenting, any sacrifices they made became insignificant, "because then the beauty happens, the magic," she said.

"We've injected the same type of cells everywhere in the heart, so they all started off alike," Taylor said. "But now when we look in the left ventricle, we find left ventricle heart cells. If we look in the atrium, they look like atrial heart cells, and if we look in the right ventricle, they are right ventricle heart cells," she said.

"So over time they've developed based on where they find themselves and grown up to work together and become a heart. Nature is amazing, isn't she?"

Billions and billions of stem cells

As her creation came to life, Taylor began to dream about a day when her prototypical hearts could be mass produced for the thousands of people on transplant lists, many of whom die while waiting. But how do you scale a heart?

"I realized that for every gram of heart tissue we built, we needed a billion heart cells," Taylor said. "That meant for an adult-sized human heart we would need up to 400 billion individual cells. Now, most labs work with a million or so cells, and heart cells don't divide, which left us with the dilemma: Where will these cells come from?"

"Now for the first time we could take blood, bone marrow or skin from a person and grow cells from that individual that could turn into heart cells," Taylor said. "But the scale was still huge: We needed tens of billions of cells. It took us another 10 years to develop the techniques to do that."

The solution? A bee-like honeycomb of fiber, with thousands of microscopic holes where the cells could attach and be nourished.

"The fiber soaks up the nutrients just like a coffee filter, the cells have access to food all around them and that lets them grow in much larger numbers. We can go from about 50 million cells to a billion cells in a week," Taylor said. "But we need 40 billion or 50 billion or 100 billion, so part of our science over the last few years has been scaling up the number of cells we can grow."

Another issue: Each heart needed a pristine environment free of contaminants for each step of the process. Every time an intervention had to be done, she and her team ran the risk of opening the heart up to infection -- and death.

"Do you know how long it takes to inject 350 billion cells by hand?" Taylor asked the Life Itself audience. "What if you touch something? You just contaminated the whole heart."

Once her lab suffered an electrical malfunction and all of the hearts died. Taylor and her team were nearly inconsolable.

"When something happens to one of these hearts, it's devastating to all of us," Taylor said. "And this is going to sound weird coming from a scientist, but I had to learn to bolster my own heart emotionally, mentally, spiritually and physically to get through this process."

Enter BAB, short for BioAssemblyBot, and an "uber-sterile" cradle created by Advance Solutions that could hold the heart and transport it between each step of the process while preserving a germ-free environment. Taylor has now taught BAB the specific process of injecting the cells she has painstakingly developed over the last decade.

"When Dr. Taylor is injecting cells, it has taken her years to figure out where to inject, how much pressure to put on the syringe, and the best speed and pace to add the cells," said BAB's creator Golway.

"A robot can do that quickly and precisely. And as we know, no two hearts are the same, so BAB can use ultrasound to see inside the vascular pathway of that specific heart, where Dr. Taylor is working blind, so to speak," Golway added. "It's exhilarating to watch -- there are times where the hair on the back of my neck literally stands up."

Taylor left academia in 2020 and is currently working with private investors to bring her creation to the masses. If transplants into humans in upcoming clinical trials are successful, Taylor's personalized hybrid hearts could be used to save thousands of lives around the world.

In the US alone, some 3,500 people were on the heart transplant waiting list in 2021.

"That's not counting the people who never make it on the list, due to their age or heath," Taylor said. "If you're a small woman, if you're an underrepresented minority, if you're a child, the chances of getting an organ that matches your body are low.

If you do get a heart, many people get sick or otherwise lose their new heart within a decade. We can reduce cost, we can increase access, and we can decrease side effects. It's a win-win-win."

Taylor can even envision a day when people bank their own stem cells at a young age, taking them out of storage when needed to grow a heart -- and one day even a lung, liver or kidney.

"Say they have heart disease in their family," she said. "We can plan ahead: Grow their cells to the numbers we need and freeze them, then when they are diagnosed with heart failure pull a scaffold off the shelf and build the heart within two months.

"I'm just humbled and privileged to do this work, and proud of where we are," she added. "The technology is ready. I hope everyone is going to be along with us for the ride because this is game-changing."

Original post:
'Ghost heart': Built from the scaffolding of a pig and the patient's cells, this cardiac breakthrough may soon be ready for transplant into humans -...

ABSTRACT

Embryonic stem cells have immense medical potential. While both their acquisition for and use in research are fraught with controversy, arguments against their usage are rebutted by showing that embryonic stem cells are not equivalent to human lives. It is then argued that not using human embryos is unethical. Finally, an alternative to embryonic stem cells is presented.

Embryonic stem cells have the potential to cure nearly every disease and condition known to humanity. Stem cells are natures Transformers. They are small cells that can regenerate indefinitely, waiting to transform into a specialized cell type such as a brain cell, heart cell or blood cell [1]. Most stem cells form during the earliest stages of human development, immediately when an embryo is formed. These cells, known as embryonic stem cells (ESCs), eventually develop into every single type of cell in the body. As the embryo develops, adult stem cells (ASCs) replace these all-powerful embryonic stem cells. ASCs can only become a number of different cells within their potency. This limited application means an adult mesenchymal stem cell cannot become a neural cell.

By harnessing the unique ability of embryonic stem cells to transform into functional cells, scientists can develop treatments for a number of diseases and injuries, according to the California Institute for Regenerative Medicine, a private organization which awards grants for stem cell research [1]. For example, scientists at the Cleveland Clinic converted ESCs into heart muscle cells and injected them into patients who suffered from heart attacks. The cells continued to grow and helped the patients hearts recover [2].

With this enormous potential to cure devastating diseases, including heart failure, spinal cord injuries and Alzheimers disease, governments and research organizations have the moral imperative to support and encourage embryonic stem cell research. President Barack Obama signed an executive order in 2009 loosening federal funding restrictions on stem cell research, saying, We will aim for America to lead the world in the discoveries it one day may yield. [3]. The National Institute of Health and seven state governments, including California, Maryland and New York, followed Obamas lead by creating programs that offered over $5 billion in funding and other incentives to scientists and research institutions for stem cell research [4].

Scientists believe that harnessing the capability of embryonic stem cells will unlock the cure for countless diseases. I am very excited about embryonic stem cells, said Dr. Dieter Egli, professor of developmental cell biology at Columbia University. They will lead to unprecedented discoveries that will transform life. I have no doubt about it. [5]. The results thus far are inspiring. In 2016, Kris Boesen, a 21-year-old college student from Bakersfield, California, suffered a severe spinal cord injury in a car accident that left him paralyzed from the neck down. In a clinical trial conducted by Dr. Charles Liu at the University of Southern California Keck School of Medicine, Boesen was injected with 10 million embryonic stem cells that transformed into nerve cells [6]. Three months after the treatment, Boesen regained the use of his arms and hands. He could brush his teeth, operate a motorized wheelchair, and live more independently. All Ive wanted from the beginning was a fighting chance, he said. The power of stem cells made his wish possible [6].

Embryonic stem cell treatments may also cure type 1 diabetes. Type 1 diabetes, which affects 42 million worldwide, is an autoimmune disorder that results in the destruction of insulin-producing beta cells found in the pancreas [7]. ViaCyte, a company in San Diego, California, is developing an implant that contains replacement beta cells originating from embryonic stem cells [7]. The implant will preserve or replace the original beta cells to protect them from the patients immune system [7]. The company believes that if successful, this strategy will effectively cure type 1 diabetes. Patients with the disease will no longer have to closely monitor their blood sugar levels and inject insulin [7]. ViaCyte projects that an experimental version of this implant will become available by 2020 [7].

Ultimately, scientists believe they will grow complex organs using stem cells within the next decade [8]. Over 115,000 people in the United States need a life-saving organ donation, and an average of 20 people die every day due to the lack of available organs for transplant, according to the American Transplant Foundation [9]. Three-dimensional printing of entire organs derived from stem cells holds the most promise for solving the organ shortage crisis [8]. Researchers at the University of California, San Diego have successfully printed part of a functional liver [8]. While the printed liver is not ready for transplant, it still performs the functions of a normal liver. This has helped scientists reduce the need for often cruel and unethical animal testing. The scientists expose drugs to the printed liver and observe how it reacts. The livers response closely mimics that of a human beings and no living animals are harmed in the process [8].

Research using embryonic stems cells provides an unprecedented understanding of human development and the potential to cure devastating diseases. However, stem cell research has generated controversy among religious organizations such as the Catholic Church as well as the pro-life movement [3]. That is because scientists harvest stem cells from embryos donated by fertility clinics. Opponents of embryonicstem cell research equate the destruction of an embryo to the murder of an innocent human being [10]. Pope Benedict XVI said that harvesting stem cells is not only devoid of the light of God but is also devoid of humanity [3]. However, this view does not reflect a reasonable understanding and interpretation of basic biology. Researchers typically harvest embryonic stem cells from an embryo five days after fertilization [1]. At this stage, the entire embryo consists of less than 250 cells, smaller than the tip of a pin. Of these cells, only 30 are embryonic stem cells, which cannot perform any human function [11]. For comparison, an adult has more than 72 trillion cells, each with a specialized function [3]. Therefore, this microscopic blob of cells in no way represents human life.

With no functional cells, there exist no characteristics of a human being. Fundamentalist Christians believe that the presence or absence of a heartbeat signifies the beginning and end of a human life [10]. However, at this stage there is no heart, not even a single heart cell [10]. Some contend that brain activity, or the ability to feel, defines a human being. Michael Gazzaniga, president of the Cognitive Neuroscience Institute at the University of California, Santa Barbara, explains in his book,The Ethical Brain,that the fertilized egg is a clump of cells with no brain. [12]. There is no brain nor nerve cells that could allow this cellular object to interact with its environment [12]. The only uniquely human feature of embryonic cells at this stage is that they contain human DNA. This means that a 5-day-old human embryo is effectively no different than the Petri dishes of human cells that have grown in laboratories for decades with no controversy or opposition. Therefore, if the cluster of cells in the earliest stage of a human embryo is considered a human life, a growing plate of skin cells must also be considered human life. Few would claim that a Petri dish of human cells is morally equivalent to a living human or any other animal. Why, then, would a microscopic collection of embryonic cells have the same moral status as an adult human?

The status of the human embryo comes from itspotentialto turn into a fully grown human being. However, the potential of this entity to become an individual does not logically mean that it has the same status as an individual who can think and feel. If this were true, virtually every cell grown in a laboratory would be subject to the same controversy. This is because scientists have developed technology to convert an ordinary cell such as a skin cell into an embryo [10]. Although this requires a laboratory with special conditions, the normal development of a human being also requires special conditions in the womb of the mother. Therefore, almost any cell could be considered a potential individual, so it is illogical to conclude that a cluster of embryonic cells deserves a higher moral status.

Hundreds of thousands of embryos are destroyed each year in a process known as in vitro fertilization (IVF), a popular procedure that helps couples have children [13]. Society has an ethical obligation to use these discarded embryos to make medical advancements rather than simply throw them in the trash for misguided ideological and religious reasons as opponents of embryonic stem cell research desire.

With IVF, a fertility clinician harvests sperm and egg cells from the parents and creates an embryo in a laboratory before implanting it in the womans womb. However, creating and implanting a single embryo is expensive and often leads to unsuccessful implantation. Instead, the clinician typically creates an average of seven embryos and selects the healthiest few to implant [13].

This leaves several unused embryos for every one implanted. The couple can pay a fee to preserve the unused embryos by freezing them or can donate them to another family. Otherwise, they are slated for destruction [14]. A 2011 study in the Journal of the American Society for Reproductive Medicine found that 19 percent of the unused embryos are discarded and only 3 percent are donated for scientific research [14]. Many of these embryos could never grow into a living person given the chance because they are not healthy enough to survive past early stages of development [14]. If a human embryo is already destined for destruction or has no chance of survival, scientists have the ethical imperative to use these embryos to research and develop medical treatments that could save lives. The modern version of the Hippocratic oath states, I will apply, for the benefit of the sick, all measures which are required [to heal] [10]. Republican Senator Orrin Hatch of Utah supports the pro-life movement, which recognizes early embryos as human individuals. However, even he favors using the leftover embryos for the greater good. The morality of the situation dictates that these embryos, which are routinely discarded, be used to improve and save lives. The tragedy would be in not using these embryos to save lives when the alternative is that they would be discarded. [3]

Although scientists have used embryonic stem cells (ESCs) for promising treatments, they are not ideal, and scientists hope to eliminate the need for them. Primarily, ESCs come from an embryo with different DNA than the patient who will receive the treatment, meaning they are not autologous. ESCs are not necessarily compatible with everyone and could cause the immune system to reject the treatment [11]. The most promising alternative to ESCs are known as induced pluripotent stem cells. In 2008, scientists discovered a way to reprogram human skin cells to embryonic stem cells [15]. Scientists easily obtained these cells from a patients skin, converted them into the desired cell type, then transplanted them into the diseased organ without risk of immune rejection [15]. This eliminates any ethical concerns because no embryos are harvested or destroyed in the process. However, induced stem cells have their own risks. Recent studies have shown that they can begin growing out of control and turn into cancer [3]. Several of the first clinical trials with induced stem cells, including one aimed at curing blindness by regenerating a patients retinal cells, were halted because potentially cancerous mutations were detected [3].

Scientists believe that induced stem cells created in a laboratory will one day completely replace embryonic stem cells harvested from human embryos. However, the only way to create perfect replicas of ESCs is to thoroughly understand their structure and function. Scientists still do not completely understand how ESCs work. Why does a stem cell sometimes become a nerve cell, sometimes become a heart cell and other times regenerate to produce another stem cell? How can we tell a stem cell what type of cell to become? To develop a viable alternative to ESCs, scientists must first answer these questions with experiments on ESCs from human embryos. Therefore, extensive embryonic stem cell research today will eliminate the need for embryonic stem cells in the future.

The Biomedical Engineering Society Code of Ethics calls upon engineers to use their knowledge, skills, and abilities to enhance the safety, health and welfare of the public. [16] Stem cell research epitomizes this. Stem cells hold the cure for numerous diseases ranging from spinal cord injuries to organ failure and have the potential to transform modern medicine. Therefore, the donation of human embryos to scientific research falls within most conventional ethical frameworks and should be allowed with minimal restriction.

Because of widespread ignorance about the science behind stem cells, ill-informed opposition has prevented scientists from receiving the funding and support they need to save millions of lives. For example, George W. Bushs religious opposition to stem cell research resulted in a 2001 law severely limiting government funding for such research [3]. Although most opponents of stem cell research compare the destruction of a human embryo to the death of a living human, the biology of these early embryos is no more human than a plate of skin cells in a laboratory. Additionally, all embryos sacrificed for scientific research would otherwise be discarded and provide no benefit to society. If society better understood the process and potential of embryonic stem cell research, more people would surely support it.

Within the next decade, stem cells will likely provide simple cures for diseases that are currently untreatable, such as Alzheimers disease and organ failure [1]. As long as scientists receive support for embryonic stem cell research, stem cell therapies will become commonplace in clinics and hospitals around the world. Ultimately, the fate of this new medical technology lies in the hands of the public, who must support propositions that will continue to allow and expand the impact of embryonic stem cell research.

By Jonathan Sussman, Viterbi School of Engineering, University of Southern California

At the time of writing this paper, Jonathan Sussman was a senior at the University of Southern California studying biomedical engineering with an emphasis in biochemistry. He was an undergraduate research assistant in the Graham Lab investigating proteomics of cancer cells and was planning to attend an MD/PhD program.

[1] Stem Cell Information,Stem Cell Basics, 2016. [Online]. Available at:https://stemcells.nih.gov/info/basics/3.htm%5BAccessed 11 Oct. 2018].

[2] Cleveland Clinic, Stem Cell Therapy for Heart Disease | Cleveland Clinic, 2017. [Online]. Available at:https://my.clevelandclinic.org/health/diseases/17508-stem-cell-therapy-for-heart-disease%5BAccessed 14 Oct. 2018].

[3] B. Lo and L. Parham, Ethical Issues in Stem Cell Research,Endocrine Reviews, 30(3), pp.204-213, 2009.

[4] G. Gugliotta,Why Many States Now Have Stem Cell Research Programs, 2015. [Online]. Available at:http://www.governing.com/topics/health-human-services/last-decades-culture-wars-drove-some-states-to-fund-stem-cell-research.html%5BAccessed 14 Oct. 2018].

[5] D. Cyranoski,How human embryonic stem cells sparked a revolution,Nature Journal, 2018. [Online]. Available at:https://www.nature.com/articles/d41586-018-03268-4%5BAccessed 11 Oct. 2018].

[6] K. McCormack,Young man with spinal cord injury regains use of hands and arms after stem cell therapy, The Stem Cellar, 2016. [Online]. Available at:https://blog.cirm.ca.gov/2016/09/07/young-man-with-spinal-cord-injury-regains-use-of-hands-and-arms-after-stem-cell-therapy/%5BAccessed 11 Oct. 2018].

[7] A. Coghlan,First implants derived from stem cells to cure type 1 diabetes,New Scientist, 2017. [Online]. Available at:https://www.newscientist.com/article/2142976-first-implants-derived-from-stem-cells-to-cure-type-1-diabetes/%5BAccessed 11 Oct. 2018].

[8] C. Scott,University of California San Diegos 3D Printed Liver Tissue May Be the Closest Weve Gotten to a Real Printed Liver,3DPrint.com | The Voice of 3D Printing / Additive Manufacturing, 2018. [Online]. Available at:https://3dprint.com/118932/uc-san-diego-3d-printed-liver/%5BAccessed 11 Oct. 2018].

[9] American Transplant Foundation,Facts and Myths about Transplant. [Online]. Available at:https://www.americantransplantfoundation.org/about-transplant/facts-and-myths/%5BAccessed 11 Oct. 2018].

[10] A. Siegel, Ethics of Stem Cell Research,Stanford Encyclopedia of Philosophy, 2013. [Online]. Available at:https://plato.stanford.edu/entries/stem-cells/%5BAccessed 11 Oct. 2018].

[11] I. Hyun,Stem Cells The Hastings Center,The Hastings Center, 2018. [Online]. Available at:https://www.thehastingscenter.org/briefingbook/stem-cells/%5BAccessed 11 Oct. 2018].

[12] M. Gazzaniga,The Ethical Brain,New York: Harper Perennial, 2006.

[13] M. Bilger,Shocking Report Shows 2.5 Million Human Beings Created for IVF Have Been Killed | LifeNews.com,LifeNews, 2016. [Online]. Available at:https://www.lifenews.com/2016/12/06/shocking-report-shows-2-5-million-human-beings-created-for-ivf-have-been-killed/%5BAccessed 11 Oct. 2018].

[14] Harvard Gazette, Stem cell lines created from discarded IVF embryos, 2008. [Online]. Available at:https://news.harvard.edu/gazette/story/2008/01/stem-cell-lines-created-from-discarded-ivf-embryos/%5BAccessed 11 Oct. 2018].

[15] K. Murray,Could we make babies from only skin cells?, CNN, 2017. [Online]. Available at:https://www.cnn.com/2017/02/09/health/embryo-skin-cell-ivg/index.html%5BAccessed 11 Oct. 2018].

[16] Biomedical Engineering Society,Biomedical Engineering Society Code of Ethics, 2004. [Online]. Available at:https://www.bmes.org/files/CodeEthics04.pdf%5BAccessed 11 Oct. 2018].

Read more from the original source:
Stem Cells: A Case for the Use of Human Embryos in Scientific Research