Xenotransplantation
Xenotranplantation is the term used to describe the transplantation of organs, tissue or cells from one species to another. It has been pursued by researchers due to the lack of available human donors and more recently, in an attempt to treat diabetes by using cells derived from pig foetuses.
History of Xenotransplantation
Transplants of organs and tissue from animals to humans have a long history but it was not until the 1960s that they moved from simple trial and error to systematic scientific study. At that time, donor organs were not available and the use of animal organs seemed promising.
Hopes were raised further in 1972 with the introduction of cyclosporin, a powerful drug that minimises the rejection of foreign tissue. Until 1992, organs generally came from chimpanzees or baboons, but in that year a pig liver was used to help a patient survive whilst a human liver was found.
In 1995, the first genetically-altered animal organs were used. The pig livers were designed to be less prone to attack by the human body and were attached to patient's circulation but kept outside their body.
So far no animal to human transplant of a whole organ can be considered successful.
1682: Bone from a dog was used to repair the skull of an injured Russian aristocrat. The operation was reportedly a success but angered the church.
1963-4: Baboon kidneys were grafted into six patients by transplant pioneer Thomas Starzl in Denver, US. The patients survived between 19 and 98 days.
1963-4: Chimpanzee kidneys were transplanted into 12 patients in New Orleans, US. Most failed within two months but one recipient survived for nine months with no sign of rejection.
1964: A 68-year-old man received a chimpanzee heart in Jackson, US, but only survived for two hours.
1969-1974: Three children received chimpanzee livers but only survived between one and 14 days.
1977: A 25-year-old woman had a baboon heart transplanted in Capetown, South Africa, and a moderate circulation was maintained but only for six hours before acute rejection. The same group also used a chimpanzee heart to assist the heart of a 60-year-old man. But despite high doses of immunosupressant drugs the patient died after four days.
1984: The Baby Fae case: A newborn baby received a baboon heart in California. Cyclosporine was used and she lived for 20 days.
Hopes were raised further in 1972 with the introduction of cyclosporin, a powerful drug that minimises the rejection of foreign tissue. Until 1992, organs generally came from chimpanzees or baboons, but in that year a pig liver was used to help a patient survive whilst a human liver was found.
In 1995, the first genetically-altered animal organs were used. The pig livers were designed to be less prone to attack by the human body and were attached to patient's circulation but kept outside their body.
So far no animal to human transplant of a whole organ can be considered successful.
1682: Bone from a dog was used to repair the skull of an injured Russian aristocrat. The operation was reportedly a success but angered the church.
1963-4: Baboon kidneys were grafted into six patients by transplant pioneer Thomas Starzl in Denver, US. The patients survived between 19 and 98 days.
1963-4: Chimpanzee kidneys were transplanted into 12 patients in New Orleans, US. Most failed within two months but one recipient survived for nine months with no sign of rejection.
1964: A 68-year-old man received a chimpanzee heart in Jackson, US, but only survived for two hours.
1969-1974: Three children received chimpanzee livers but only survived between one and 14 days.
1977: A 25-year-old woman had a baboon heart transplanted in Capetown, South Africa, and a moderate circulation was maintained but only for six hours before acute rejection. The same group also used a chimpanzee heart to assist the heart of a 60-year-old man. But despite high doses of immunosupressant drugs the patient died after four days.
1984: The Baby Fae case: A newborn baby received a baboon heart in California. Cyclosporine was used and she lived for 20 days.
1992: A four-drug cocktail assisted a baboon liver transplant. The patient died of a brain haemorrhage after 71 days. The type of rejection typical in cross-species transplantation was not seen.
1992: A pig liver was implanted next to patient's own liver to buy time for a human organ to be found but the patient died after 32 hours.
1993: Baboon bone marrow and kidney transplant carried out in Pittsburgh, US with same drug cocktail used as in 1992 case. However, the patient's suppressed immune system succumbs to infection after 26 days.
Source: BBC NEWS
1992: A pig liver was implanted next to patient's own liver to buy time for a human organ to be found but the patient died after 32 hours.
1993: Baboon bone marrow and kidney transplant carried out in Pittsburgh, US with same drug cocktail used as in 1992 case. However, the patient's suppressed immune system succumbs to infection after 26 days.
Source: BBC NEWS
Painful experiments on animals
Animals suffer terribly during xeno research. They are often genetically-modified, and recipient animals must have their immune system suppressed to lessen the chance of rejection.
The ‘Diaries of Despair’, an expose by British group Uncaged, is a harrowing report of the suffering. Uncaged’s Director, Dan Lyons, stated in an interview “One of the most unfortunate animals had a piglet heart transplanted into his neck. It was a particularly disturbing example, I think, because for several days he was holding the heart. It was swollen. It was seeping blood; it was seeping pus as a result of the infections that often occur in the wound site. He suffered from body tremors, vomiting, diarrhea. And the animal just sat there. I think living hell is really the only sort of real way you can get close to describing what it must be like to have been that animal in that situation.”
Note: Uncaged Campaigns has achieved an astonishing legal success by winning the right to publish the Diaries of Despair report and over a thousand pages of confidential documents. Uncaged Campaigns argued successfully that it was in the public interest to reveal the shocking truth behind one of Britain's most extreme programs of animal experiments in recent history.
For more information, please visit: www.xenodiaries.org
The ‘Diaries of Despair’, an expose by British group Uncaged, is a harrowing report of the suffering. Uncaged’s Director, Dan Lyons, stated in an interview “One of the most unfortunate animals had a piglet heart transplanted into his neck. It was a particularly disturbing example, I think, because for several days he was holding the heart. It was swollen. It was seeping blood; it was seeping pus as a result of the infections that often occur in the wound site. He suffered from body tremors, vomiting, diarrhea. And the animal just sat there. I think living hell is really the only sort of real way you can get close to describing what it must be like to have been that animal in that situation.”
Note: Uncaged Campaigns has achieved an astonishing legal success by winning the right to publish the Diaries of Despair report and over a thousand pages of confidential documents. Uncaged Campaigns argued successfully that it was in the public interest to reveal the shocking truth behind one of Britain's most extreme programs of animal experiments in recent history.
For more information, please visit: www.xenodiaries.org
Risk of a Zoonotic pandemic
AIDS, BSE (Mad Cow Disease), Ebola viruses and some of the major flu epidemics such as Avian flu, originated from cross-species contamination. Porcine Endogenous Retrovirus (PERV) has already been discovered in the animals intended to be used as a source for organ donors. Current tests are unable to diagnose potential xenozoonotic viruses with their unknown pathogenic behaviour, and, even if detected, the viruses are largely untreatable.
Risk to the wider community
Not only would clinical trials be exposing the organ (or tissue) recipient to major health risks, but these risks would also be extended to the recipient’s carers and families and the wider community. Considering that viruses may initially show no obvious signs of disease and may spread beyond the recipient into the general population before they become evident, at what stage will researchers deem their patients as no longer carrying any risk? And during that period before the disease is identified or acknowledged, how many people are likely to have been exposed to that disease? Certainly an individual has the right to expose themselves to any risks involved in scientific research but to further expose that risk to the wider community, who have NOT given consent, is highly unethical. Indeed the number of individuals that could suffer and die from a new epidemic could greatly exceed those potential lives which xenotransplantation was supposed to have saved in the first place.
Source: Humane Research Australia
Risk to the wider community
Not only would clinical trials be exposing the organ (or tissue) recipient to major health risks, but these risks would also be extended to the recipient’s carers and families and the wider community. Considering that viruses may initially show no obvious signs of disease and may spread beyond the recipient into the general population before they become evident, at what stage will researchers deem their patients as no longer carrying any risk? And during that period before the disease is identified or acknowledged, how many people are likely to have been exposed to that disease? Certainly an individual has the right to expose themselves to any risks involved in scientific research but to further expose that risk to the wider community, who have NOT given consent, is highly unethical. Indeed the number of individuals that could suffer and die from a new epidemic could greatly exceed those potential lives which xenotransplantation was supposed to have saved in the first place.
Source: Humane Research Australia