The Beast Within: Implanting Animal Organs into Humans

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Are animal-to-human organ transplants the future of medicine?

Getting an organ these days is no easy task. Currently, there are more than 100,000 people on waiting lists for organ donations in the United States, but fewer than 30,000 transplants were performed in 2008. The Mayo Clinic estimates that in the United States, 17 people die each day while waiting for a suitable organ to come along.Complicating the donation deficiency is the fact that people in need of kidney transplants comprise at least three-quarters of the waiting list. Meanwhile, Americans' insalubrious diets, sloth-like tendencies, and general unhealthiness-all of which increase the need for kidney transplants-also end up limiting the pool of possible donors.And, to make matters grimmer still, even if you check the organ-donor box on the back of your state I.D. card, it doesn't mean much; about one-third of willing donors end up going to the grave with their organs because family members and significant others don't sign the final consent form.It's quite the conundrum. So what to do? Increasingly, the argument for harvesting organs, tissues, and cells from animals is picking up steam. It sounds like the stuff of sci-fi, but a growing number of scientists are arguing for-and trying to accomplish-just that. The most recent experiment is in New Zealand, where a clinical trial will inject eight diabetic patients with pancreatic cells from pigs. This experiment has pushed the controversial field, known as xenotransplantation, under the public microscope once again.

As far back as 1889, physicians were shooting up slivers of dog and guinea pig testicles to study "human revitalization therapy."

Last month, the Journal of the American Medical Association ran a piece by Dr. Richard Pierson about the current status of xenotransplantation. While Pierson makes a compelling argument for the need to go forward with this research, he pays great attention to the many ethical concerns and health risks-such as introducing new diseases to the human species and suppressing patients' immune systems to dangerous levels-that accompany these types of procedures.Still, the concept of cross-species transplantations is nothing new. As far back as 1889, physicians were shooting up slivers of dog and guinea pig testicles to study "human revitalization therapy." Through the years, though, there has been significant progress made in the field, and biotech companies have invested heavily in developing transgenic animals and immunosuppressant drugs.Ethics and public health worries, however, continually impede this research, and with good reason. In 1997 the FDA halted all xenotransplantations amidst concerns that a retrovirus previously confined to pigs could infect humans, but the moratorium was lifted in 1998. Scientists have looked to the cells and organs of other species as possible cures for everything from neurological diseases to HIV, and there seems to be some indication that these procedures could be tremendously beneficial.Xenotransplantation has a curious history and a controversial future. Here's a look at four notable cases:Surgeon: Muhammad Baha' al DawlaYear: 1501Animal borrowed from: DogThe first documented xenotransplantation is credited to this Iranian surgeon. In 1501, Baha' al Dawla used a fragment of dog skull to repair a patient's infected skull. Oddly enough, according to researchers at Brown University, the surgeon used a slice of cucumber to shield the recipient's brain during the procedure.Surgeon: Mathieu JaboulayYear: 1906Animals borrowed from: Pig, goatIn an attempt to circumvent a patient's defunct kidneys, this French surgeon transplanted the kidney of a pig into the nook of a lady's elbow on January 24, 1906. The pig kidney produced more than 40 ounces of urine, but had to be removed due to clotting, and the patient eventually died. Later that year, Jaboulay transplanted the kidney of a goat into a woman suffering renal failure. She, too, died.Surgeon: Leonard BaileyYear: 1984Animal borrowed from: BaboonIn the fall of 1984, the world became enthralled by the case of Baby Fae. The premature newborn, known as "Baby Fae" to protect her privacy, struggled with hypoplastic left heart syndrome-a usually fatal disease in which the entire left side of the heart, including the aorta, is underdeveloped. The infant had little chance of surviving more than a few weeks. Then, in October of that year, a surgeon in California transplanted the heart of a 7-month-old baboon into the infant's chest. While Baby Fae's surgery was considered effective initially, her immune system quickly rejected the simian heart and she died three weeks later. This is perhaps the most well-known and heavily scrutinized xenotransplantation in history.Surgeon: Dr. Susan IlstadtYear: 1995Animal borrowed from: Baboons againThe iconic AIDS activist Jeff Getty had little patience for the bureaucracy of the FDA. In the 1980s he was caught smuggling unapproved AIDS medication into the United States from Mexico, and, years later, he volunteered to be part of an experiment that could have killed him. In 1995, Dr. Susan Ilstadt of the University of Pittsburgh injected baboon bone marrow into Getty, in hopes that it would spur the development of cells that could fight the disease while remaining HIV-resistant. "We were hoping to create two immune systems functioning side by side, the human and the baboon," Getty told The New York Times in 1998. Though his health did improve the year of the surgery, the baboon marrow had quickly dissipated from his system and is not credited for this improvement. Getty died in 2006 due to heart failure after struggling with AIDS and cancer.Would you consider accepting an animal organ if the technology to do so was in place?