The support and
opposition to xenotransplantation—the transplant of organs from one
species to another—are both based on truth.
It is true that there are far too few human organs available to be
transplanted into individuals who will likely die without such a
transfer. And it is true that the use of animal organs that have been
altered to overcome barriers presented by cross-species
rejection is an increasingly enticing solution to the shortage.
But it is also chillingly true that it is impossible to know what is
being transplanted along with such organs. The threat of an
as-yet-unknown disease making the cross-species jump with a heart,
liver, kidney, or other body part alarms experts such as Jonathan
Allan, a virologist at the Southwest Foundation for Biomedical
Research. In particular, he said, it is difficult to test for the
presence of a virus if you do not know it exists. The threat that a new
epidemic could spring from such transplants is alarmingly real, said
Allan in an interview last fall.
Yet it appears the US Food and Drug Administration, Centers for Disease
Control and Prevention, and other federal agencies are ready to issue
guidelines that would allow trials of xenotransplants to
begin—again.
In truth, xenotransplants have a long history in modern medicine. In
early 1964, Keith Reemtsma, MD, of Tulane University oversaw
xenotransplantation of kidneys from chimpanzees into six patients, one
of whom lived 9 months after the transplant. Other transplants
followed, including those by transplant veteran Thomas Starzl, MD,
at
© 1998 American Heart Association, Inc.
Cardiovascular News
Xenotransplantation