What’s the benefit in making human-animal hybrids? – The Conversation AU
By raymumme
The red shows rat cells in the developing heart of a mouse embryo.
A team of scientists from the Salk Institute in the United States created a stir last week with the announcement that they had created hybrid human-pig foetuses.
The story was widely reported, although some outlets took a more hyperbolic or alarmed tone than others.
One might wonder why scientists are even creating human-animal hybrids often referred to as chimeras after the Greek mythological creature with features of lion, goat and snake.
The intention is not to create new and bizarre creatures. Chimeras are incredibly useful for understanding how animals grow and develop. They might one day be used to grow life-saving organs that can be transplanted into humans.
The chimeric pig foetuses produced by Juan Izpisua Belmonte, Jun Wu and their team at the Salk Institute were not allowed to develop to term, and contained human cells in multiple tissues.
The actual proportion of human cells in the chimeras was quite low and their presence appeared to interfere with development. Even so, the study represents a first step in a new avenue of stem cell research which has great promise. But it also raises serious ethical concerns.
A chimera is an organism containing cells from two or more individuals and they do occur in nature, albeit rarely.
Marmoset monkeys often display chimerism in their blood and other tissues as a result of transfer of cells between twins while still in the womb. Following a successful bone marrow transplantation to treat leukaemia, patients have cells in their bone marrow from the donor as well as themselves.
Chimeras can be generated artificially in the laboratory through combining the cells from early embryos of the same or different species. The creation of chimeric mice has been essential for research in developmental biology, genetics, physiology and pathology.
This has been made possible by advances in gene targeting in mouse embryonic stem cells, allowing scientists to alter the cells to express or silence certain genes. Along with the ability to use those cells in the development of chimeras, this has enabled researchers to produce animals that can be used to study how genes influence health and disease.
The pioneers of this technology are Oliver Smithies, Mario Cappechi and Martin Evans, who received a Nobel Prize in Physiology or Medicine in 2007 for their work.
More recently, researchers have become interested in investigating the ability of human pluripotent stem cells master cells obtained from human embryos or created in the laboratory from body cells, to contribute to the tissues of chimeric animals.
Human pluripotent stem cells can be grown indefinitely in the laboratory, and like their mouse counterparts, they can form all the tissues of the body.
Many researchers have now shown they can make functional human tissues of medical significance from human pluripotent cells, such as nerve, heart, liver and kidney cells.
Indeed, cellular therapeutics derived from human pluripotent stem cells are already in clinical trials for spinal cord injury, diabetes and macular degeneration.
However, since 2007 it has been clear that there is not one type of pluripotent stem cell. Rather, a range of different types of pluripotent stem cells have been generated in mice and humans using different techniques.
These cells appear to correspond to cells at different stages of embryonic development, and therefore are likely to have different properties, raising the question about which source of cells is best.
Creating a chimeras has long been the gold standard used by researchers to determine the potential of pluripotent stem cells. While used extensively in animal stem cell research, chimeric studies using human pluripotent stem cells have proved challenging as few human cells survive in human-animal chimeras.
Although the number of human cells in the chimera was low, the findings by the Salk Institute researchers provide a new avenue to address two important goals. The first is the possibility of creating humanised animals for use in biomedical research.
While it is already possible to produce mice with human blood, providing an invaluable insight into how our blood and immune system functions, these animals rely on the use of human fetal tissue and are difficult to make.
The use of pluripotent stem cells in human-animal chimeras might facilitate the efficient production of mice with human blood cells, or other tissues such as liver or heart, on a larger scale. This could greatly enhance our ability to study the development of diseases and to develop new drugs to treat them.
The second potential application of human-animal chimeras comes from some enticing studies performed in Japan in 2010. These studies were able to generate interspecies chimeras following the introduction of rat pluripotent stem cells into a mouse embryo that lacked a key gene for pancreas development.
As a result, the live born mice had a fully functional pancreas comprised entirely of rat cells. If a similar outcome could be achieved with human stem cells in a pig chimera, this would represent a new source of human organs for transplantation.
While scientifically achieving such goals remains a long way off, it is almost certain that progress in pluripotent stem cell biology will enable successful experimentation along these lines. But how much of this work is ethically acceptable, and where do the boundaries lie?
Many people condone the use of pigs for food or as a source of replacement heart valves. They might also be content to use pig embryos and foetuses as incubators to manufacture human pancreas or hearts for those waiting on the transplant list. But the use of human-monkey chimeras may be more contested.
Studies have shown that early cells of the central nervous system made from human embryonic stem cells can engraft and colonise the brain of a newborn mouse. This provides a proof of concept for possible cellular therapies.
But what if human cells were injected into monkey embryos? What would be the ethical and cognitive status of a newborn rhesus monkey whose brain consists of predominantly human nerves?
It may be possible to genetically engineer the cells so that human cells can effectively grow into replacement parts. But what safeguards do we need to ensure that the human cells dont also contribute to other organs of the host, such as the reproductive organs?
While the announcement of a human-pig chimera may have taken many by surprise, regulators and medical researchers well recognise that chimeric research may raise issues in addition to the those already posed by animal research.
However, rather than call for a blanket ban or restricting funding for this area of medical research, it requires careful case-by-case consideration by independent oversight committees fully aware of animal welfare considerations and recognising existing standards.
For example, The 2016 Guidelines for Clinical Research and Translation from the International Society for Stem Cell Research call for research where human gametes could be generated from human-animal chimeras to be prohibited, but supports research using human-animal chimeras conducted under appropriate review and oversight.
Chimeric research will and needs to continue. But equally scientists involved in this field need to continue to discuss and consider the implications of their research with the broader community. Chimeras can all too readily be dismissed as mythological monsters engendering fear.
Visit link:
What's the benefit in making human-animal hybrids? - The Conversation AU
- 001 Ying Liu discusses IPS cell therapy for ALS [Last Updated On: August 6th, 2011] [Originally Added On: August 6th, 2011]
- 002 Jeanne Loring talks about stem cells, part 2 [Last Updated On: September 5th, 2011] [Originally Added On: September 5th, 2011]
- 003 Embryonic Stem Cells From Skin: Making Old Cells Young [Last Updated On: September 5th, 2011] [Originally Added On: September 5th, 2011]
- 004 IPs cells Part3 [Last Updated On: September 6th, 2011] [Originally Added On: September 6th, 2011]
- 005 IPs cells Part 2 [Last Updated On: September 7th, 2011] [Originally Added On: September 7th, 2011]
- 006 A Century of Stem Cells - Johns Hopkins Medicine [Last Updated On: September 7th, 2011] [Originally Added On: September 7th, 2011]
- 007 Stem Cell Implications for ALS (Amyotrophic Lateral Sclerosis) [Last Updated On: September 7th, 2011] [Originally Added On: September 7th, 2011]
- 008 Myelin Repair Foundation on Stem Cell Research [Last Updated On: September 9th, 2011] [Originally Added On: September 9th, 2011]
- 009 IPs Cells Part 4 [Last Updated On: September 11th, 2011] [Originally Added On: September 11th, 2011]
- 010 National Medical Report [Last Updated On: September 13th, 2011] [Originally Added On: September 13th, 2011]
- 011 IPs cells Part 1 [Last Updated On: September 15th, 2011] [Originally Added On: September 15th, 2011]
- 012 iPS Stem Cell-Based Treatment of Epidermolysis Bullosa [Last Updated On: September 16th, 2011] [Originally Added On: September 16th, 2011]
- 013 Jeanne Loring talks about stem cells, part 1 [Last Updated On: September 16th, 2011] [Originally Added On: September 16th, 2011]
- 014 Kristopher Nazor 2 [Last Updated On: September 16th, 2011] [Originally Added On: September 16th, 2011]
- 015 Andalusian Stem Cell Bank [Last Updated On: September 19th, 2011] [Originally Added On: September 19th, 2011]
- 016 Cellular Reprogramming Stem Cell Domain Name For Sale! - CellularReprogramming.com [Last Updated On: September 20th, 2011] [Originally Added On: September 20th, 2011]
- 017 Dr. Oz to Oprah and Michael J Fox: "The stem cell debate is dead." [Last Updated On: September 22nd, 2011] [Originally Added On: September 22nd, 2011]
- 018 Manning, Owens Try Stem Cell Therapy [Last Updated On: October 5th, 2011] [Originally Added On: October 5th, 2011]
- 019 Jeanne Loring talks about stem cells, part 3 [Last Updated On: October 5th, 2011] [Originally Added On: October 5th, 2011]
- 020 Epidermolysis Bullosa: Corrected iPS Stem Cell-Based Therapy - Video [Last Updated On: October 13th, 2011] [Originally Added On: October 13th, 2011]
- 021 Introduction to Stem Cells - Video [Last Updated On: October 14th, 2011] [Originally Added On: October 14th, 2011]
- 022 Parkinson's Disease: Progress and Promise in Stem Cell Research - Video [Last Updated On: October 14th, 2011] [Originally Added On: October 14th, 2011]
- 023 stem cell research - Video [Last Updated On: December 7th, 2011] [Originally Added On: December 7th, 2011]
- 024 Ian Wilmut discusses stem cell and direct cellular transformation therapy - Video [Last Updated On: December 8th, 2011] [Originally Added On: December 8th, 2011]
- 025 Jeff Bluestone: Immune rejection of stem cell transplants - Video [Last Updated On: December 8th, 2011] [Originally Added On: December 8th, 2011]
- 026 Advances in Stem Cell Research: Shinya Yamanaka - Video [Last Updated On: December 11th, 2011] [Originally Added On: December 11th, 2011]
- 027 2011 Summit: Stem Cells, Reprogramming and Personalized Medicine, Rudolf Jaenisch, MD - Video [Last Updated On: December 14th, 2011] [Originally Added On: December 14th, 2011]
- 028 Parkinson's Disease: Advancing Stem Cell Therapies - 2011 CIRM Grantee Meeting - Video [Last Updated On: January 20th, 2012] [Originally Added On: January 20th, 2012]
- 029 Professor Alan Trounson - World focus on stem cell research - Video [Last Updated On: January 27th, 2012] [Originally Added On: January 27th, 2012]
- 030 Stanford scientists turn skin cells into neural precusors, bypassing stem-cell stage [Last Updated On: January 31st, 2012] [Originally Added On: January 31st, 2012]
- 031 Researchers turn skin cells into neural precusors, bypassing stem-cell stage [Last Updated On: January 31st, 2012] [Originally Added On: January 31st, 2012]
- 032 “Wide-ranging applications for pluripotent stem cells” [Last Updated On: February 2nd, 2012] [Originally Added On: February 2nd, 2012]
- 033 Radiation treatment transforms breast cancer cells into cancer stem cells [Last Updated On: February 14th, 2012] [Originally Added On: February 14th, 2012]
- 034 Radiation Treatment Generates Cancer Stem Cells from Less Aggressive Breast Cancer Cells [Last Updated On: February 14th, 2012] [Originally Added On: February 14th, 2012]
- 035 Radiation treatment generates cancer stem cells from less aggressive breast cancer cells, study suggests [Last Updated On: February 14th, 2012] [Originally Added On: February 14th, 2012]
- 036 Life Technologies Scientist Uma Lakshmipathy presents, "Solving Challenges in the Generation of Induced Pluripotent ... [Last Updated On: February 14th, 2012] [Originally Added On: February 14th, 2012]
- 037 Radiation therapy transforms breast cancer cells into cancer stem cells [Last Updated On: February 14th, 2012] [Originally Added On: February 14th, 2012]
- 038 Research and Markets: Primary and Stem Cells: Gene Transfer Technologies and Applications [Last Updated On: February 15th, 2012] [Originally Added On: February 15th, 2012]
- 039 Horizon in new super-cell elite [Last Updated On: February 16th, 2012] [Originally Added On: February 16th, 2012]
- 040 Presentations at the Society of Toxicology Annual Meeting Demonstrate Superior Predictivity of Cellular Dynamics ... [Last Updated On: March 8th, 2012] [Originally Added On: March 8th, 2012]
- 041 New approach to treating type 1 diabetes? Transforming gut cells into insulin factories [Last Updated On: March 12th, 2012] [Originally Added On: March 12th, 2012]
- 042 Gut cells transformed into insulin factories 'could help to treat type I diabetes' [Last Updated On: March 12th, 2012] [Originally Added On: March 12th, 2012]
- 043 A new approach to treating type I diabetes? Gut cells transformed into insulin factories [Last Updated On: March 12th, 2012] [Originally Added On: March 12th, 2012]
- 044 Columbia Researchers Find Potential Role for Gut Cells in Treating Type I Diabetes [Last Updated On: March 12th, 2012] [Originally Added On: March 12th, 2012]
- 045 Study demonstrates cells can acquire new functions through transcriptional regulatory network [Last Updated On: March 14th, 2012] [Originally Added On: March 14th, 2012]
- 046 Gut Cells Turned To Insulin Factories - New Type l Diabetes Treatment [Last Updated On: March 14th, 2012] [Originally Added On: March 14th, 2012]
- 047 Cellular Dynamics Expands Distribution Agreement with iPS Academia Japan, Inc. to Include Distribution of iCell ... [Last Updated On: March 28th, 2012] [Originally Added On: March 28th, 2012]
- 048 :: 20, Apr 2012 :: IBN DISCOVERS HUMAN NEURAL STEM CELLS WITH TUMOR TARGETING ABILITY – A PROMISING DISCOVERY FOR ... [Last Updated On: April 22nd, 2012] [Originally Added On: April 22nd, 2012]
- 049 Human neural stem cells with tumor targeting ability discovered [Last Updated On: April 22nd, 2012] [Originally Added On: April 22nd, 2012]
- 050 IBN Discovers Human Neural Stem Cells, Promising Discovery For Breast Cancer Therapy [Last Updated On: April 22nd, 2012] [Originally Added On: April 22nd, 2012]
- 051 IBN Discovers Human Neural Stem Cells with Tumor Targeting Ability - A Promising Discovery for Breast Cancer Therapy [Last Updated On: April 22nd, 2012] [Originally Added On: April 22nd, 2012]
- 052 VistaGen Secures Key U.S. Patent Covering Stem Cell Technology Methods Used to Test Drug Candidates for Liver Toxicity [Last Updated On: April 25th, 2012] [Originally Added On: April 25th, 2012]
- 053 Improved adult-derived human stem cells have fewer genetic changes than expected [Last Updated On: May 2nd, 2012] [Originally Added On: May 2nd, 2012]
- 054 Researchers restore neuron function to brains damaged by Huntington's disease [Last Updated On: May 31st, 2012] [Originally Added On: May 31st, 2012]
- 055 Cellular Dynamics Launches MyCell™ Services [Last Updated On: June 7th, 2012] [Originally Added On: June 7th, 2012]
- 056 Fate Therapeutics And BD Biosciences Launch BD™ SMC4 To Improve Cellular Reprogramming And IPS Cell Culture Applications [Last Updated On: June 12th, 2012] [Originally Added On: June 12th, 2012]
- 057 Life Technologies and Cellular Dynamics International Partner for Global Commercialization of Novel Stem Cell ... [Last Updated On: June 13th, 2012] [Originally Added On: June 13th, 2012]
- 058 LIFE Focuses on Stem Cell Research - Analyst Blog [Last Updated On: June 20th, 2012] [Originally Added On: June 20th, 2012]
- 059 International Stem Cell Corp Granted Key Patent for Liver Disease Program [Last Updated On: September 30th, 2012] [Originally Added On: September 30th, 2012]
- 060 NeuroGeneration Recruits Top Scientist To Direct New Division of Biotherapeutics and Drug Discovery In La Jolla, CA [Last Updated On: October 5th, 2012] [Originally Added On: October 5th, 2012]
- 061 FRC Supports Alliance Defending Freedom, Jubilee Campaign Cert Petition to Supreme Court on Stem Cell Funding [Last Updated On: October 11th, 2012] [Originally Added On: October 11th, 2012]
- 062 10/11/2012 10:05 JAPAN Nobel Prize for Yamanaka, scientific research and ethics must go hand in hand [Last Updated On: October 11th, 2012] [Originally Added On: October 11th, 2012]
- 063 Read in [Last Updated On: October 12th, 2012] [Originally Added On: October 12th, 2012]
- 064 Induced pluripotent stem cell - Wikipedia, the free encyclopedia [Last Updated On: November 3rd, 2013] [Originally Added On: November 3rd, 2013]
- 065 What are induced pluripotent stem cells or iPS cells? - Stem Cells ... [Last Updated On: November 3rd, 2013] [Originally Added On: November 3rd, 2013]
- 066 Stem Cell Definitions | California's Stem Cell Agency [Last Updated On: November 3rd, 2013] [Originally Added On: November 3rd, 2013]
- 067 iPSCTherapy.com: Induced Pluripotent Stem Cell therapy Information ... [Last Updated On: November 8th, 2013] [Originally Added On: November 8th, 2013]
- 068 Human muscle stem cell therapy gets help from zebrafish [Last Updated On: November 8th, 2013] [Originally Added On: November 8th, 2013]
- 069 Induced pluripotent stem cell therapy - Wikipedia, the free ... [Last Updated On: November 8th, 2013] [Originally Added On: November 8th, 2013]
- 070 IPS Cell Therapy - Genetherapy [Last Updated On: November 8th, 2013] [Originally Added On: November 8th, 2013]
- 071 MD Supervised Stem Cell Therapy [Last Updated On: November 9th, 2013] [Originally Added On: November 9th, 2013]
- 072 Stem Cell Therapy for Neuromuscular Diseases | InTechOpen [Last Updated On: November 23rd, 2013] [Originally Added On: November 23rd, 2013]
- 073 Combining Stem Cell Therapy with Gene Therapy | Boston ... [Last Updated On: November 25th, 2013] [Originally Added On: November 25th, 2013]
- 074 Biomanufacturing center takes central role in developing stem ... [Last Updated On: December 4th, 2013] [Originally Added On: December 4th, 2013]
- 075 Stem Cell Quick Reference - Learn Genetics [Last Updated On: December 6th, 2013] [Originally Added On: December 6th, 2013]
- 076 Induced Pluripotent Stem Cells (iPS) from Human Skin: Probable ... [Last Updated On: December 6th, 2013] [Originally Added On: December 6th, 2013]
- 077 'Something positive for humankind': Girls lend cells to genetic study [Last Updated On: December 13th, 2013] [Originally Added On: December 13th, 2013]
- 078 Stem cell science: Can two girls help change the face of medicine? [Last Updated On: December 13th, 2013] [Originally Added On: December 13th, 2013]
- 079 Okyanos Heart Institute CEO Matt Feshbach Congratulates Japan’s Legislators On Stem Cell Bill And Global Regulatory ... [Last Updated On: December 13th, 2013] [Originally Added On: December 13th, 2013]
- 080 Stem cells for Parkinson's getting ready for clinic [Last Updated On: December 13th, 2013] [Originally Added On: December 13th, 2013]
