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Cloning pigs for parts


by Jeffrey P. Kahn, Ph.D., M.P.H.
Director, Center for Bioethics
University of Minnesota

The same biotechnology company that brought us Dolly the sheep, along with one of its competitors, announced it has now successfully cloned genetically modified pigs. What’s special about these pigs is that they have certain of their genes shut off or “knocked out,” which the companies hope could eventually lead to growing animals whose organs can be transplanted into humans.

This could be a major medical advance that would change the way we think about organ transplantation. We might move from the current situation of severe shortage and patients dying long before organs become available, to a time when organ transplant could be treated like other surgeries.

But transplanting animal organs into humans – known as xenotransplantation -- raises its own issues. How safe will organs from animals be for humans? Is it acceptable to engineer and grow animals so that their organs can be used for human transplants? And if everyone who needed a transplant was to receive one, what impact would that have on our health care systems?

Saving lives or risking public health?

The major question about transplanting animal organs into people is whether they will introduce animal pathogens into humans. How safe must a technology be before it is used in clinical trials on humans, let alone introduced into the practice of medicine? This is a special concern in xenotransplantation, since even if individual patients are willing to accept the uncertain risk in research, it's not clear they should be allowed to expose themselves to risks that may well go beyond the individual and affect the public's health. This could happen if a new virus or other as yet undetectable infectious agent were introduced into the human population by transplanted animal tissue.

Even if they are eventually deemed sufficiently safe, xenotransplants may not be as effective as transplanted human organs. So in cases where patients can wait in relatively good health for a human organ to become available, as is often the case in kidney transplant, should patients forego waiting for a human organ to accept a potentially less effective and more risky animal organ? The answer isn't clear, and is further clouded by the fact that there is a potentially huge market that biotechnology companies are hoping to capitalize upon.

Animal parts for human uses?

If and when xenotransplant makes its way into human research and potentially human medicine, there will be loud protests from animal rights activists about whether it is acceptable to genetically engineer and farm animals so that their parts can be used by humans.

This question should make us all think about what other uses humans have for animals, beginning with the fact that many people eat them. Is raising them for transplantable organs any different than raising them for food? In terms of the welfare of domesticated animals, species that are genetically engineered for their organs may actually receive better treatment because of their medical value.

Transplants instead of what else?

Finally, these new and very expensive technologies raise serious questions about the use and allocation of health care resources.

The billions of dollars that might be spent on xenotransplant will likely save many lives and improve the health of many others, but we ought to consider what is being traded off if we choose to adopt this technology. This point is especially relevant for health care systems that already face economic constraints, as many throughout the world do. This is not a unique issue for xenotransplantation to be sure, but one to add to the list of ethical issues raised by it.

Xenotransplants may one day be part of 21st century medicine, and will likely extend from organs to skin and other tissues, including blood and bone. But these successes will not come cheap.

As we prepare for the future, the questions are whether we’ll be willing to pay their price -- in uncertain risk, the use of animals, and the use of ever-limited health care resources.

Visit the
"Ethics Matters" Archive
where you'll find other columns from Jeffrey Kahn
on a wide range of bioethics topics.

"Ethics Matters" is a biweekly feature from the
Center for Bioethics and CNN Interactive.


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