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Xenografts: Frankenstein Science

Xenografts are surgical transplants in which donor and recipient are members of different species. The success rate for xenografts is zero.(1) Transplantation of vital organs and other body parts, such as bone marrow, taken from other-than-human animals has been attempted as part of experimental treatments for degenerative organ diseases and viral infections like hepatitis and AIDS. After several decades of research, xenografts have proved to be extremely costly failures that may pose serious health risks to the public.

A Bloody Trail

Since 1905, at least 34 pigs, chimpanzees, monkeys, and baboons have been made the unwilling "donors" of kidneys, hearts, livers, and bone marrow for transplantation into humans.(2) The misery inflicted on such experimental animals begins at birth, with delivery by surgical hysterectomy, after which they are placed in an "isolette" in an attempt to keep them free of infectious agents.(3) Animals are subjected to the sensory deprivation of a sterile laboratory environment and denied all social interaction with members of their own species. When the time comes for them to "donate" their organs, they are killed.

Every one of these experiments has failed, with most recipients dying within a few hours, days, or weeks.

Bad Science

The human immune system is designed to identify and reject foreign objects. Human-to-human transplants have relied on immunosuppressive drugs to control rejection of the transplanted organ. Genetic differences make transplants from other species particularly noticeable to the human immune system. Even chimpanzees, our closest relatives, are six times as different from us as we are from each other, and the risk of rejecting a baboon organ is 25 times greater than for an unmatched human organ.(4) Xenograft researchers have developed increasingly powerful immunosuppressive therapies to try to overcome this natural reaction. The drawback is that these treatments create an immune deficiency that leaves the recipient vulnerable to often fatal infections.

Hidden Dangers

In several recent xenograft experiments, researchers have cited the differences among species to try to justify the use of animal organs. In 1992, a team led by Dr. Thomas Starzl of the University of Pittsburgh transplanted a baboon liver into a 35-year-old man who was suffering from hepatitis B. The experimenters reasoned that since the hepatitis virus does not cause liver damage in baboons, a baboon liver would increase his chances of survival. Two months later, the patient died of a massive brain hemorrhage.(5)

In 1995, AIDS patient Jeff Getty received a transplant of bone marrow taken from a baboon. Baboons infected with the Human Immunodeficiency Virus (HIV), the virus presumed to cause AIDS, do not develop the life-threatening immune deficiency that characterizes human AIDS. Bone marrow is an important component of the immune system, and Getty's doctors hypothesized that by transferring this component to their patient they could create a "parallel" immune system that would fight the virus. But just weeks after the transplant, the doctors were forced to admit that the experiment had failed and no trace of the baboon cells could be found in the patient.(6)

Prior to approving the Getty experiment, the Food and Drug Administration held a conference with experts in immunology to discuss dangers and potential benefits. There was general agreement that the procedure was more likely to kill the patient than to help him.(7) In fact, many in the scientific community are calling for a moratorium on all xenografts because of the danger of unleashing new diseases into the human population. Many microbes that are completely harmless in one species cause disease in others. Baboons, for example, routinely carry infectious agents that are harmful or deadly to humans. Among them are Yersinia pestis, which causes bubonic plague, the Marburg virus, and the lethal Ebola virus and hantavirus.(8) In addition to known pathogens, animals may also harbor as-yet-unidentified viruses, bacteria, and parasites which could prove deadly to people. Many human epidemics, AIDS included, can probably be traced to microbes "jumping" from one species to another.

Informed Consent?

As with any hazardous medical procedure, xenograft recipients are required to sign an informed consent form before undergoing the procedure, stating that the patient understands the risks involved and the alternatives available. It is doubtful that desperately ill patients are given all the facts when considering xenograft procedures. Many believe their doctors are attempting to save their lives, rather than performing futile experiments on them. In 1984, doctors at Loma Linda University in California transplanted a baboon heart into an infant born with serious heart defects. "Baby Fae" died 20 days later. Afterwards, an independent review panel determined that there were at least three other options--all more promising than a xenograft--available to treat her condition. The baby's mother, who was alone and virtually destitute, was never informed of these options. Many medical ethicists condemned Dr. Leonard Bailey, who performed the experiment, for leading Baby Fae's mother to believe that the doomed experiment offered hope for her baby's survival.

Costly Failures

In addition to the toll in human and animal lives, xenografts divert precious resources away from truly life-saving efforts to treat disease. Each xenograft procedure costs between $250,000 and $300,000 to perform.(9) The University of Pittsburgh's experimental transplant program alone receives more than $8 million each year in funding, largely through federal grants from the National Institutes of Health. Meanwhile, many promising new treatments for AIDS and other life-threatening diseases go unexplored because of lack of funding. National organ donor procurement programs receive less than half a million dollars annually.

Even basic programs which have proved to save lives, like those that provide housing, primary care, and treatment to people with AIDS, have suffered cutbacks due to resource constraints. Most of the diseases for which xenografts have been proposed, including AIDS, hepatitis B, and other degenerative organ diseases, are preventable, yet prevention programs receive little to no public funding.

Become an Organ Donor

Advocates of cross-species transplants point to the scarcity of human organ donors to justify continued efforts in this field. Every year, thousands of Americans are buried with organs that are suitable for donation, far exceeding the 3,400 who die while on organ donor waiting lists.(10) European organ donor policies assume that every person is an organ donor unless otherwise specified. The burden rests with individuals (or their families) if they do not wish to donate their organs. Even within the current system, patients have a better chance of long-term survival by waiting for a last-minute human organ than by choosing a xenograft.(11)

In 1986, PETA initiated a campaign to save animal and human lives by encouraging people to become organ donors. To request a free organ donor card, write to PETA, 501 Front Street, Norfolk, Va., 23510 or call 757-622-PETA.

References

1. Associated Press Wire Report, "Doctors Call Use of Baboon Livers 'Bad Science,'" Los Angeles Times, Feb. 1, 1993.
2. Steele, David J.R., and Hugh Auchincloss, "The Application of Xenotransplantation in Human--Reasons for Delay," ILAR Journal, 37(1): 13-15, 1995.
3. Michaels, Marian, and Richard Simmons, "Xenotransplant-Associated Zoonoses," Transplantation, 57: 1-7, 1994.
4. Lowenstein, Jerold, "Fundamental Damage," BBC Wildlife, Aug. 1986.
5. Doris, Margaret, "The Animal Within: The Risks and Ethics of Trans-Species Transplants," New York Perspectives, Oct. 16, 1992.
6. Boudreau, John, "Baboon Cells Not Found in Patient," Contra Costa Times, Feb. 8, 1996.
7. Altman, Lawrence, "Doctors Treating AIDS Patient Turn to Baboon Marrow Cells," The New York Times, Dec. 15, 1995.
8. Thacher, Wendy, "Transplantation Information," Physicians Committee for Responsible Medicine News Release, Jul. 1, 1992.
9. Altman.
10. Colburn, Don, "Organ Donations Hinge on Survivors' Consent," The Washington Post Health Section, Aug. 4, 1995.
11. Steele and Auchincloss.