Interspecies differences interdict cross-species transplants
Pig organs have evolved to support an animal with a life span of 10 years as opposed to 80 or more years for humans. In addition, their organs are designed to function differently from the corresponding organs in humans:
Pigs are a horizontal animal. Their hearts have not evolved to pump blood against gravity into the brain of an upright animal. This, besides the fact that they have evolved to support an animal with a shorter life span is sufficient reason not to attempt pig-to-human transplants in addition to the fact that all those that have been attempted have predictably failed as have transplants from other primates.
There is a major difference in the way pig and human kidneys process uric acid. Humans reabsorb 90 percent of the amount that is processed whereas pigs secrete it. There is also a hormonal difference affecting the production of red blood cells.
Pig livers do not produce guanase, an enzyme that affects the functioning of the human immune system. Pig livers do contain uricase, however, which breaks down uric acid which humans metabolize as is.
Even subtle interspecies differences such as the above can upset the balance each individual human body is constantly working to maintain.
Immune systems of transplant patients already compromised
To compound the problems presented by interspecies differences, transplant patients' immune systems are deliberately suppressed with drugs in order to prevent rejection of the transplants , which a healthy immune system would see as a foreign invader and promptly reject. Having a weakened immune system makes transplant recipients more susceptible to the opportunistic expansion of any stray organisms that might hitch a ride with a transplant.
Genetically altered animals
Compounding the problem still further is the fact that the pigs used will have been genetically altered opening up still more possibilities for acquiring and transmitting.existing and as yet unknown diseases. Xenotransplant proponents claim that their pigs will be carefully screened for viruses, bacteria, fungi and parasites, but, as Australian virologist Peter Kirkland wrote in New Scientist, "You can't screen for viruses you don't know about."
Financial considerations
In addition to all the medical and public health caveats to both xenotransplants and allotransplants, there is the practical matter of the monetary effect, in addition to the health effects, on the human population as a whole.
Many Americans are unable to afford basic health care or insurance. It is unfair that the government should contribute public money to developing transplants, especially dubious xenotransplants, for the benefit of the minority of people who can afford them when so many more are unable to afford diagnosis and treatment of their health problems.
Keeping pigs in a controlled environment to prevent exposure to bacteria, viruses, fungi, and parasites is an expensive undertaking compared to using organs from people whom medical treatment failed to save. The cost of their medical treatment is not a factor because they would have received it anyway.
Because of the possibility of dangerous new human diseases resulting from xenotransplants, there is also the cost of monitoring the recipients of xenotransplants. One of the worst scenarios that has been suggested is maintaining separate colonies of xenotransplant recipients--like the leper colonies of old--to protect the rest of the human population from rampaging viruses and bacteria.
The best all-round solution
The best long-term solution to the organ shortage problem is to reduce the need for transplants by educating and persuading more people to adopt a healthy lifestyle. If people would take responsibility for their own health instead of expecting doctors to patch them up after years of abusing their bodies with unhealthy eating (to say nothing of tobacco, alcohol and drugs), fewer people would need transplants. The supply of donated organs would then come closer to the smaller number of people still in need of them.
Respectfully submitted,
Bina Robinson
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Campaign for Responsible Transplantation http://www.crt-online.org
