Alberta Innovates- Health Solutions

Rejection of transplanted material remains a major obstacle to successful animal-to-human transplantation.

A baboon heart was transplanted into a 15-day-old infant in California in 1982. Baby Fae lived with the primate organ for twenty days before her tiny body ultimately rejected it. Her fight for life made banner headlines as she became one of the youngest humans to undergo xenotransplantation.

Nearly twenty years later, rejection of transplanted material is still a major obstacle to successful animal-to-human organ, cell, or tissue transplantation. Concern about xenozoonoses-the spread of animal infections to humans-is also a major concern, notes Dr. Thérèse Leroux, a University of Montreal law professor, and panelist at the ethics in genetics conference held recently in Edmonton.

International regulatory measures must be put in place to prevent renegade scientists from proceeding with further organ transplants before issues around xenozoonoses and organ rejection can be resolved, says Dr. Abdallah Daar, who chaired a World Health Organization (WHO) consultation on xenotransplantation. "The fear is that you're just going to get cowboys who are going to go ahead and do this, what is called expatriate research, somewhere where there are unregulated regimes and perhaps under the guise of some other experiment," he comments.

Animal organs have come into scientific focus because the demand for human organs outstrips their availability. According to recent reports, in Canada alone, demand for organ transplants rose by 68% in the last decade. Scientists believe pigs could offer a potentially unlimited supply of donor organs for humans. Pigs breed quickly and their anatomy and physiology are similar to humans.

Whether or not there is enough scientific data in place to proceed to large-scale clinical trials is a matter of opinion, Dr. Daar says. "In the United States, the scientific conclusion is we have gone as far as we can go with laboratory and animal research and we are only going to know if this will work in human beings if we put the organs in human beings." In Europe, he explains, the view is more cautious. Scientists there believe that the risk is too big and the knowledge base too small at present to proceed with clinical trials. He predicts there will be enormous pressure to proceed to clinical trials within the next two years.

Thérèse Leroux, Ph.D., is a law professor and researcher at the Université de Montréal. Her current research projects include a focus on legal and ethical aspects of human experimentation and xenotransplantation.

Dr. Abdallah S. Daar is currently the Chair of the Department of Surgery at the Sultan Qaboos University College of Medicine in Oman and a visiting professor in the University of Toronto's Faculty of Law and the Joint Centre for Bioethics.