Baboon Living With Pig Heart For 945 Days Hints Successful Xenotransplantation

The success behind the beating pig heart inside the body of a live baboon for 945 days could help address global organ shortages. Researchers from Bethesda, Maryland's National Heart, Lung and Blood Institute had hoped the  record-setting outcome will help scientists understand the potential of xenotransplantation, the transfer of animal organs into humans.

The case had various animal species considered as candidates for organ transfer. Chimpanzees, on top of all others, were the obvious choice due to their organ sizes and right blood type compatibility. However, they were ruled out because they were endangered animals.

Baboons were also considered, but had their own set of issues such as small body size, lack of blood type O and longer gestation period. This had led to pigs being the organ donor of choice, because they shared many complementary proteins that humans and their organs had. Organs were also of similar sizes, according to a feature from Science Alert.

A pig heart, however, had negative response from the recipient's immune systems and this had been the source of most issues surrounding xenotransplantation. Previously, the team managing the case has had many early transplant rejections resulting in protein incompatibility between pigs and baboons.

To smash the previous milestone of 179 days, a group of baboons had been given immune-suppressing drugs containing key antibodies called anti-CD40. The drug exhibited the potential to avoid attacks by the immune system.

The organs of the genetically modified pigs were also designed to lack alpha1-3 galactosyltransferase, a very aggressive enzyme that will cause blood clots in recipients. The scientists stated that it was this combination that resulted to the success of the project.

The pig's heart had lowered immunosuppressant dose over the course of the experiment with the researchers giving baboons lower medication doses in hopes that they will grow tolerant of the pig heart. However, as soon as the anti-CD40 left the system, the primate died, ArsTechnica reported.