Baboons with pig hearts pave way for human transplants

The unprecedented survival of pig hearts in four baboons for almost 600 days has revived hopes that animal organs could help alleviate the global shortage of organs for transplant.

Huge strides have been made in recent years creating and successfully transplanting human organs using stem cell technology. Despite this, the potential for using animal organs in humans – xenotransplantation – remains attractive because the supply is theoretically limitless, and could supply organs of any size.

However, the technology has taken decades to get off the ground, because of safety fears and problems with organ rejection.

"We're confident we've tackled most of the immunological barriers, and although it would be very premature to speculate on a timeline to the first transplant in humans, I would say we are much closer to clinical reality," says Muhammad Mohiuddin of the US National Heart, Lung and Blood Institute in Bethesda, Maryland, who lead the latest baboon trial.

Until now, pig hearts have survived for up to six months in monkeys, so the latest results treble the survival time. The piglets from which the hearts were taken were genetically engineered to disguise their hearts from the baboons' immune systems and to prevent blood clots from forming in the organ.

Because the experiments were designed to check for rejection rather than function, the hearts were plumbed into blood vessels in the baboons' abdomens, enabling the baboons to rely on their native hearts to circulate their blood.