Pig organs cleared for human transplant

TOM WILKIE

Science Editor

Surgeons and scientists should be allowed to transplant the hearts and kidneys of genetically engineered pigs into humans, but forbidden from using body parts from chimpanzees or baboons to save human lives, according to a panel of experts.

The Nuffield Council on Bioethics yesterday called on the Government to set up a national advisory committee on xenografting - animal to human organ transplants - to put controls and regulations in place before the first experiments are carried out on human patients.

Professor Albert Weale, of the University of Essex and chairman of the Nuffield Council's working party, said: "Xenotransplantation promises much - the shortage of donor organs can be overcome. Around 5,000 patients are on the waiting list for transplants but because of the shortage of donated human organs, less than 3,000 transplants were performed in 1995."

Because the benefits could be so considerable, Professor Weale said the working party had decided that "it would be ethically acceptable to develop the technique experimentally".

But he stressed it should proceed with caution. In September last year, a British company, Imutran, announced it had transplanted organs from genetically engineered pigs into monkeys and hoped to transplant pig hearts into humans within the next couple of years.

Despite the hype surrounding the experiments, their outcome is unclear. The working party stressed that the first transplants on humans would be highly experimental and recommended that patients should seek independent advice. Only adults in terminal conditions should be considered initially.

By ruling out transplants from chimpanzees, baboons and other higher primates, the council delivered a discreet rebuff to developments in the US. In 1984, in the highly publicised case of "Baby Face", a young baby received a baboon heart, but survived only 20 days. In 1992 and 1993, American surgeons tried again by transplanting baboon livers into two patients - neither survived longer than 70 days.

The Nuffield Council argued that although higher primates made technically suitable donors, theirclose genetic relationship with humans made it morally unacceptable to use them for that end. The working party also said that primates breed too slowly to be a ready source of organs.

Worse however was the possibility that primates might harbour viruses or other diseases which could prove both virulent and infectious in humans.

Pigs are more suitable because they are prolific breeders, not an endangered species, and because we already use them in ways that we do not use chimpanzees - such as eating them. "If eating animals is allowed for the pleasures of the palate," Professor Weale said, "it would appear logical to allow their use for transplantation."

Pigs organs are so "foreign" that they provoke rejection by the human immune system. The animals must therefore have human genes implanted in them to "humanise" their organs.