Tuesday, August 20, 2002

"Seldom, if ever, have we had as much knowledge to prevent a future epidemic. What is lacking is the wisdom to act upon that knowledge." See AFMA's "Letter concerning xenotranplantation" and "Piggies to market."

PROBLEMS WITH XENOTRANSPLANTATION

Pig Livers to the Rescue?
Vexing questions at the frontiers of science
By Bryn Nelson Staff Writer
August 20, 2002

One scenario envisions doctors delivering a limitless supply of livers, hearts and other organs to save the lives of countless transplant patients. In another, doctors unwittingly release a horrific plague upon unsuspecting millions....

In 1963, in New Orleans, Tulane University surgeon Keith Reemtsma performed the first xenotransplants of the modern medical era, using chimpanzee kidneys. A pair of the transplanted organs worked for nearly nine months in one patient.

Since then, doctors have tried transplanting hearts, kidneys and livers from baboons, chimpanzees, pigs and sheep. All have ultimately failed...

Conversely, several factors have kept nonhuman primates from emerging as likely candidates. The kidneys of baboons, for example, are smaller than those of humans. And because most primates used in studies are caught in the wild, they may harbor a broader range of pathogens than animals bred in captivity. Some scientists also believe viruses from primates may cross over to humans more readily than pathogens from pigs, a contributing factor in the FDA's 1999 call to halt the use of nonhuman primates in clinical xenotransplant studies. HIV, now thought to have arisen in chimpanzees, provides a stark example....

Animal rights activists say continued efforts to improve xenotransplant survival times in nonhuman primates could require the sacrifice of countless more monkeys, chimpanzees and baboons. And eventually, such research could pave the way for the slaughter of thousands of pigs bred as human organ factories. The outcry has been particularly harsh in the United Kingdom, where observers say the public is more aligned against animal research.

Significant obstacles remain on the scientific front as well, especially the human body's rejection of anything perceived as foreign....