Kill a baboon, save a man?

Arthur Caplan

July 22, 1992|By Arthur Caplan

A 35-YEAR-OLD man dying of liver failure received a transplant on June 29.

There is nothing especially newsworthy about that, since there are more than 2,000 liver transplants performed each year in the United States.

What was remarkable was that the liver came from a baboon. This was the first attempt to use a liver from a baboon in a human recipient. So far, the transplant seems to be going well.

While it is still too early to say that the experiment is a success, it is not too early to examine the morality of this experiment with a baboon liver.

Most of the ethical commentary that accompanied the experiment has focused on the question of the morality of killing a baboon to save a human life. But is there really a moral issue about the propriety of killing a baboon to save a person?

Perhaps it is morally wrong to kill animals to eat them, for sport or for their furs. But can anyone take seriously the idea that we ought to flip a coin in weighing the moral value of a baboon and a human?

People are moral agents; baboons are not. If one must die to save the other, that may be tragic, but the choice of whom to sacrifice seems clear.

More vexing, if less widely discussed, are the questions of whether the time had come to try this experiment in a human being and, if so, what the overall aim is of such research. Even if the experiment works and the patient survives with a reasonable quality of life, it still is not clear that the Pittsburgh experiment should get unqualified passing ethical grades.

The surgeons at Pittsburgh gave two reasons to justify their decision to try using an animal transplant, or xenograft. The recipient of the baboon liver, who continues to request anonymity, is infected with hepatitis B. This virus was responsible for the destruction of his liver.

The doctors in Pittsburgh said the man probably would not have been eligible for a human cadaver liver transplant due to his hepatitis, and that the odds of the hepatitis virus reinfecting a new liver, if he somehow got one, were low.

Are these reasons persuasive?

When the baboon liver transplant was being done, I was in Strasbourg, France, at an international conference of experts in xenografting. Some of the surgeons there said that they would accept into their programs patients dying from liver failure as a result of hepatitis. A few of the surgeons and scientists who were there expressed skepticism about whether or not a baboon liver was vulnerable to hepatitis infection, but many thought the odds were probably lower.

The only way to know whether baboon livers are vulnerable to destruction by human hepatitis virus is to infect them. And the only way to know whether a transplanted baboon liver can do what a liver is supposed to do in another species is to transplant some.

But a good case can be made that the experimental subjects that Pittsburgh should be using are other primates, not a man. Even if it is true that the fellow who got the baboon liver had little or no chance of getting a human cadaver liver, this would not justify using him as an experimental subject. Hopeless terminal illness is not enough of a reason to justify an experiment.

Researchers need to have adequate scientific information to support the idea that a baboon transplant might work. The best way to get this information is to do the basic work on primate to primate transplants. It is not clear that the first liver xenograft had been preceded by adequate research in animals.

There is another moral problem with the use of a baboon as the source of a liver. There are not all that many baboons around who live in healthy, disease-free environments. While the researchers at Pittsburgh clearly hope that other people might be able to benefit from a baboon transplant if the experiment works, the reality is that there are so few baboons now living in breeding colonies that it would take years, if not decades, to breed a larger number of others.

The experts at the meeting in Strasbourg agreed that over the next five years it would be very hard to find more than a couple of hundred baboons to use as possible sources of livers and other organs. If xenografting research is going to solve the terrible shortage of hearts, livers, kidneys and other organs and tissues available for transplant to those in need, it is going to have to focus on abundant animals such as pigs, cows or goats.

If the goal of transplanting a baboon liver is to find alternative sources for the thousands of people who die each year for want of organs, then it is doubtful that baboon transplants are going to be of much help even if the current experiment works. If that is so then the morality of the current experiment is less self-evident.

Arthur Caplan is director of the Center for Biomedical Ethics at the University of Minnesota Medical School.

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