Bioethics in India: Proceedings of the International Bioethics Workshop in Madras: Biomanagement of Biogeoresources, 16-19 Jan. 1997, University of Madras; Editors: Jayapaul Azariah, Hilda Azariah, & Darryl R.J. Macer, Copyright Eubios Ethics Institute 1997.

31. Ethical and social issues in xenotransplantation

Darryl R.J. Macer.
Institute of Biological Sciences, University of Tsukuba, Tsukuba Science City, 305, Japan.

Organ transplants have been performed for several decades using human organs from live and dead donors to replace diseased or defective organs in patients. The success rates are now very high for histocompatibility matched organs, for example 5 year average survival rates of 90% for kidneys and hearts, and 80% for livers, are common in many hospitals. The ethical issues are also discussed by Tharien, Sheriff and Verma.

One of the fundamental problems in this technology is the shortage of supply of many organs for providing enough transplants for all those people who could benefit from receiving one. These pressures have led to some ethical abuses, such as stealing of organs from persons without their consent, and exploitation of poor persons to sell their organs to rich buyers. Most persons however cannot receive organs and die. Therefore there has been research into the use of animal organs and tissues as replacements.

The basic technical problem is immunological rejection of animal tissues. There have to be ways to protect the new cells from the immune system, which can be obtained though three basic ways: physical barriers such as membranes around the new cells; chemical suppression of the immune system through immunosuppressant drugs; and modification of the new cells so they appear to be the same. In the future another way is research to produce artificial blood, and tissue such as hearts (Canadian Med. Ass. J. 156 (1997), 553-5). Already plastics and metals are used in bone operations.

Experiments with transplants of fetal pig pancreas to diabetic patients have found that it can survive (Groth et al., 1994). There are also ways that can be used to put the cells producing a compound in a dialysis bag so that they can produce hormones or substances, while being immune protected.

Genetic engineering can be used to express human proteins on the cell surface to make the animal cells "human" (Fodor et al. 1994; Cozzi & White, 1995). The heart is a relatively simple organ in terms of rejection because it is basically a pump. In one set of trials involving pig heart transplants to rhesus monkeys there was an average survival in 10 monkeys of 40 days, although the initial goal was only 2 days survival (Lancet 346 (1995), 766). Another method being developed to overcome hyperacute xenograft rejection reactions is based on reshaping the foreign sugar molecules that cause much of this problem. Skin graft tolerance has also been obtained for xenotransplants (Nature Medicine 2 (1996), 1185-6, 1211-6).

If the animals are raised humanely, and killed humanely, then we could consider this medical farm as an extension of food and fibre farming. The UK Nuffield Council on Bioethics (1996) report on the ethics of xenotransplantation, recognized a potential benefit, and said that the breeding of pigs for patients who need organs is ethically justified, rather than using primates. They called for the establishment of a committee to monitor the safety. The British Medical Association agreed with the views of the Nuffield Council. However a 1997 UK government report from the Advisory Group on the Ethics of Xenotransplantation recommended no animal tissue be transplanted into humans at present because of safety fears. This has led to a ban on them (Nature Biotechnology 15 (1997), 214). The US Institute of Medicine also prepared guidelines (JAMA 276 (1996), 589-90), as did the US Department of Health and Human Services (Lancet 348 (1996), 953; New Scientist (28 Sept. 1996), 7). The ethical issues will continue to be debated, (Hanson, 1995; Palca, 1995; McCarthy, 1996; Mepham, et al 1996), for example whether we should use animals for organs, and what are the limits of medicine in terms of prolonging life, quality of life, and costs of technology. The safety concerns are based on the fears of prion or virus transmission (Nature 376 (1995), 8; Lancet 345 (1995), 69-74), and are the reasons for the temporary ban in the UK, and the hesitance elsewhere.

Once the disease safety, technical issues and ethical issues have been overcome, which I they will be, another issue is public acceptance. A survey of 1728 acute care nurses in Australian public hospitals found the majority said that they would not accept an organ from a baboon or chimpanzee, with similar distaste for pig or sheep organs (Nature 378 (1995), 434). However, other opinion surveys suggest the public is more split, and that when the technology becomes safe it will be adopted for use.

International research raises the issue of how universal bioethics are, and whether different standards can be applied to different peoples. Can people travel abroad for medical procedures in one country and return to their own, perhaps acquiring new viruses abroad as is common for blood transfusions and sexual encounters. Results of an International Bioethics Survey conducted in more than a dozen countries since 1993 (in India with Jayapaul and Hilda Azariah) suggest the same diversity of opinions on many issues raised by biology is found inside each society (Macer, 1994).

There are two ways to think of the term "bioethics", one is as descriptive bioethics - the way people view life and their moral interactions and responsibilities with living organisms in life. The other is prescriptive bioethics - to tell others what is good or bad, what principles are most important; or to say something/someone has rights and therefore others have duties to them. Both these concepts have much older roots, which we can trace in religions and cultural patterns that may share some universal ideals. However these new technologies may challenge us to think about our ethics again, and the images of what is natural change over time. So those who reject xenografts today may become users tomorrow, especially when their life may be substantially improved by it. We may be able to live without eating meat, but one day very soon some people will not be able to live without the help of animal tissue donors. Bioethics would give them the choice to live or die according to their own values, providing it does not do more harm than what is accepted already.

Advisory Group on the Ethics of Xenotransplantation. Animal Tissue into Humans (The Stationary Office, formerly HMSO, London 1997, 25 pounds, ISBN 011-321866-4).
Cozzi, E. & White, D.J.G. "The generation of transgenic pigs as potential organ donors for humans", Nature Medicine 1 (1995), 964-8.
Fodor, W.L. et al. "Expression of a functional human complement inhibitor in a transgenic pig as a model for the prevention of xenogeneric hyperactive organ rejection", PNAS 91 (1994), 11153-7.
Groth, C.G. et al. "Transplantation of porcine fetal pancreas to diabetic patients", Lancet 344 (1994), 1402-4.
Hanson, M.J., "The seductive sirens of medical progress. The case of xenotransplantation", Hastings Center Report 25 (5, 1995), 5-6.
Macer, DRJ. Bioethics for the People by the People (Eubios Ethics Institute, 1994).
McCarthy, CR "A new look at animal-to-human organ transplantation", Kennedy Institute of Ethics Journal 6 (1996), 183-8.
Mepham, TB et al. "An ethical analysis of the use of xenografts in human transplant surgery", Bulletin of Medical Ethics 116 (1996), 13-9.
Nuffield Council on Bioethics, Animal-to-Human Transplants, The Ethics of xenotransplantation, 1996, ISBN 0-9522701-2-9, 146pp.
Palca, J. "Animal organs for human patients", Hastings Center Report 25 (5, 1995), 4.

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