Is There Role for Public in Pig-to-Human Transplants?

Scientists, speaking at the AAAS Annual Meeting in Boston, said on Sunday that clinical trials to test the feasibility of transplanting pigs' organs into humans could begin within five to seven years. But a debate broke out between them over how extensively to prepare the public for such an event.

After a period of frustrating set-backs, transplantation surgeons have recently found reason for optimism: The authors of a research article in Science (8 February 2002) reported using genetic engineering to create four piglets born with only one copy of the gene that normally causes pig cells to be rejected by humans. The pigs will now be bred normally to try and create pigs born with no copy of the gene at all.

"I consider this a major step forward," said David Cooper, an associate professor of surgery at Harvard Medical School, and an immunologist at the Transplantation Biology Research Center at Massachusetts General Hospital. "Until this happened, we had hit a brick wall. We had tried various solutions, but the most time we could buy (with transplantation in experimental animals) was five or six weeks of life."

Cooper’s colleague on the panel, Fritz Bach, a professor of surgery at Harvard Medical School and Beth Israel Deaconess Medical Center, and director of the Immunobiology Research Center, agreed on the time frame for when clinical trials might proceed, given recent scientific advances. But he argued that such research should not go forward until the public has had a chance to give a societal equivalent of informed consent.

"I have proposed a moratorium to allow time for the public to be involved in this process. And one of the reasons is because of the potential for unknown viruses," said Bach, who sat with Cooper on a panel entitled, "Animal Parts for Humans? Xenotransplantation Science, Ethics, Policy and Publics."

Risk of Infection from Pigs

Researchers have extensively studied pig cells for evidence of viruses that might put humans at risk. They have been buoyed by the discovery of pigs that are infected with "PERVs," or porcine endogenous retroviruses, that are incapable of entering and infecting human cells. There may be other, yet unknown pig-borne viruses, however, as well as potential combination viruses created from the union between human and porcine tissue. Bach noted that a dying patient might be willing to accept a risk of infection that might be unacceptable to society at large. And, under the terms of informed consent, a patient can leave an experimental program at any time, Bach said, so society cannot ensure that an individual will continue to be monitored for infection.

"It would be immoral for us not to engage the public and listen very carefully to what they have to say," Bach said.

Cooper responded that a lack of sophistication among members of the general public would prevent them from fully understanding "the nuances" of the xenotransplantation debate.

"Committees will have to be formed to represent the public," he said.

Agnes Allandottir, a lecturer at the University of Siena in Italy who has studied European public opinion regarding biotechnology issues, suggested that researchers and policymakers should consider the level of public trust.

"How does the system work?" she asked. "Is there trust in scientists and in regulators that they will act in the best interests of the public?"

But Cooper pointed out that people had made a poor showing in response to efforts to obtain the donation of human organs. "We’ve been trying for 30 years, and we’re no better off that we were 30 years ago."

If all scientific barriers were overcome, Cooper asked Bach, "would we proceed, Fritz?"

"Yes," answered Bach. "But I hope we would have public input and safeguards in place. The point is that the public must help us to decide how to protect ourselves from the risk."

-- Coimbra Sirica

Read more: Canadian Public Wants Moratorium on Clinical Trials