The Public Health Service recently issued guidelines for Xenotransplantation — the transplanting of animal cells, tissues and organs to treat or mitigate human diseases. As the background statement to the guidelines notes, 13 people in the United States die every day while waiting for an organ transplant and any advance that utilized animal tissues or organs would save many lives.
There are legitimate concerns about risks, however. The biggest fear, which the activists latch onto, is the risk of passing a disease from a non-human to a human. After all, for as long as humans have domesticated animals or used them as a source of food, diseases have passed between animals and humans. The most familiar of these diseases is the influenza virus which relies on several different species, including humans, pigs, and birds, as disease vectors in which it thrives and mutates.
It is certainly reasonable to take some precautions, but the message of the activists is that there is no acceptable risk. The misnamed Campaign for Responsible Transplantation, for example, immediately denounced the new guidelines as inadequate largely because they believe that it is impossible for Xenotransplantation to be risk free. Instead the CRT’s Alix Fano wants the United States to adopt the “precautionary principle.” This essentially means always minimizing risk regardless of the possible benefit, which very few people seem to actually agree with if their behavior is any evidence (if you regularly drive a car, for example, you are implicitly rejecting the precautionary principle.)
There is also a certain irony that much of the legitimate fear of a possible spread of a disease across species boundaries comes from the very animal research which Fano and others believe is done for no better reason than to enrich the pockets of scientists. For example, the PHS guidelines note that researchers have shown that simian foamy virus in baboons has been found to persist in human beings who received liver cell transplantations from human beings. Similarly, in vitro research has demonstrated that retrovirus carried by pigs can infect human cell lines. This stuff scares the anti-xeno activists to death, but then again I thought all these claims that human and non-human physiologies were very close was just corporate double talk?
The proposed guidelines find the reasonable middle ground — researchers should do everything possible to minimize the risk of this happening, but the risk is not great enough to forego the advantages of this technology. The PHS calls for a strict regimen of monitoring and health surveillance system coupled with strict requirements for animal procurement which will reduce the risk of a highly infectious agent ever crossing the boundary between animals and human beings through xenotransplantation very low.
For example, the obvious way to reduce risk of transmitting diseases is to use animals that are free of diseases. The PHS guidelines call for “procuring source animals from herds or colonies that are screened and qualified as free of specific pathogenic infectious agents and that are maintained in an environment that reduces exposure to vectors of infectious agents.” Essentially this means implementing what the industry had already been moving to — animals intended for Xenotransplantation use will be special breeding populations that are kept under special clean laboratory conditions. Of course, the activists will complain in turn that this violates the welfare of the animals.
Which is really the point of CRT despite all its attempts to sound like a scientifically-minded public interest group. Most people might consider the idea using cells from animals to perhaps cure diabetes as a good thing, but not CPT:
Who will decide how much animal suffering is justified? Up to 100 pig fetuses may be needed for a single transplantation of pig pancreatic islet cells into a diabetic patient. Each patient may need several transplants during the course of treatment. That’s a lot of pigs for one person.
Not even pigs, after all, but pig fetuses.
Sources:
Anti-Xenotransplanation Coalition Denounces New Federal Guideline. Press release, Campaign for Responsible Transplantation, May 31, 2000.
Public Health Service Guideline on Infectious Disease Issues in Xenotransplantation. Public Health Service, 2000.