Xenografts: Frankenstein Science

Xenografts are surgical transplants in which the donors and recipients are members of different species. The transplantation of vital organs and other body parts, such as bone marrow, between humans and animals has been attempted as part of experimental treatments for degenerative diseases and viral infections such as hepatitis and AIDS. After several decades of research, xenografts have proved to be extremely costly failures that pose serious health risks to people.

Animals Sacrificed for Bad Science
Since the 20th century, dozens of pigs, chimpanzees, monkeys, and baboons have been made the unwilling “donors” of kidneys, hearts, livers, and bone marrow for transplantation into humans.(1) Additionally, thousands of goats, rats, chickens, cats, and dogs have died in cross-species experimentation.(2) The focus has recently shifted from using nonhuman primates to using pigs because pigs are easier for researchers to obtain. Yet pigs’ physiology is strikingly different from that of humans. Scientific American explained that “pig cells sport sugar molecules on their surfaces that can trigger a violent immune response in the transplant recipient—an assault that can kill the donor organ in minutes.”(3) So scientists worldwide are working to genetically alter pig DNA in an attempt to make it more compatible with human DNA. Korea, for example, is spending more than $60 billion over the next decade to “mass produce pig organs for human transplants.”(4)  

These animals are subjected to sensory deprivation in sterile laboratory environments and are denied social interaction with members of their own species. One investigation of a British research facility revealed the torturous lives and deaths of animals subjected to “xenotransplantation”: Monkeys and baboons died “in fits of vomiting and diarrhoea,” a pig’s heart was attached to the arteries in the pig’s neck while researchers observed the heart swell to an abnormal size, and “other animals retreated within themselves, lying still in their cages until put of their misery.”(5) Please visit “Diaries of Despair” for the complete report.

Every one of these experiments has failed—most transplant recipients die within a few hours, days, or weeks of surgery.

Why Xenotransplantation Doesn’t Work
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. Xenograft researchers have developed increasingly powerful immunosuppressive therapies to try to overcome this natural reaction. These treatments create an immune deficiency that leaves the recipient vulnerable to often-fatal infections.

Hidden Dangers
Researchers have cited the differences between species to try to justify the use of animal organs in xenotransplantation experiments. In one case, 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 because the hepatitis virus does not cause liver damage in baboons, a baboon liver would increase the man’s chances of survival. Two months later, the patient died of a massive brain hemorrhage.(6)
 
In another instance, AIDS patient Jeff Getty received a transplant of bone marrow 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. Just weeks after the transplant, however, the doctors were forced to admit that the experiment had failed, and no trace of the baboon cells could be found in the patient.(7)  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 a general agreement that the procedure was more likely to kill the patient than to help him.(8) 

Many microbes that are completely harmless to one species cause disease in others. One virologist warned that transplantation of animal organs into humans “means that viruses not typically thought to be infectious for humans such as blood-borne or sexually [transmitted] pathogens would now have access to human organ systems.”(9)  The virus that causes AIDS may have originated in nonhuman primates. A human influenza virus that killed millions of people in 1918 was a mutation of “swine flu.”(10)  In addition to known pathogens, animals may also harbor unidentified viruses, bacteria, and parasites that could prove deadly to people.

What You Can Do
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 more than 7,000 who die while on organ-donor waiting lists.(11) 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. Patients have a better chance of long-term survival if they wait for a last-minute human organ than they do if they receive the organ of a tortured animal.
 
References
1) David J.R. Steele and Hugh Auchincloss Jr., “The Application of Xenotransplantation in Humans—Reasons to Delay,” ILAR Journal 37 (1995): 13-15.
2) Alix Fano et al., “Of Pigs, Primates, and Plagues: A Layperson’s Guide to the Problems With Animal-to-Human Organ Transplants,” Medical Research Modernization Committee, 1997.
3) “Cloned GM Piglets May Pave Way to Xenotransplantation Success,” ScientificAmerican.com, 4 Jan. 2002.
4) “Korea to Mass-Produce Pig Organs for Human Transplants,” The Sydney Morning Herald 1 Jun. 2004.
5) Mark Townsend, “Exposed: Secrets of the Animal Organ Lab,” The Observer 20 Apr. 2003.
6) Margaret Doris, “The Animal Within: The Risks and Ethics of Trans-Species Transplants,” NY Perspectives 16 Oct. 2002.
7) John Boudreau, “Baboon Cells Not Found in Patient,” The Times 8 Feb. 1996.
8) Lawrence K. Altman, “Hope in AIDS Case Is Put in Marrow From Baboon,” The New York Times 15 Dec. 1995.
9) Jonathan S. Allan, “Xenotransplantation at a Crossroads: Prevention Versus Progress,” Nature Medicine 2 (1996): 18.
10) Paul Recer, “Researchers Solve Genetic Puzzle of 1918 Influenza Pandemic,” The Associated Press, 21 Mar. 1997.
11) United Network for Organ Sharing, “Reported Deaths and Annual Death Rates Per 1,000 Patients-Years at Risk Waiting List, 1994 to 2003,” OPTN/SRTR Annual Report 3 May 2004.