Researchers at South Korea’s National Institute of Animal Science (NIAS) have announced that a macaque has survived for 51 days with a pig’s heart, breaking the country’s previous record of 43 days. Importantly, the monkey has not been taking any immunosuppressant drugs, which are normally necessary in order to stop a transplant recipient’s immune system from attacking and destroying donor organs.
Because pig hearts are similar in size to those of humans, they are seen by many scientists as a good candidate for heart transplants. However, xenotransplantation – meaning the transfer of organs between animals of different species – is extremely complicated, as each organism’s immune system is primed to eliminate all alien material.
It is therefore necessary to genetically alter organs before inserting them into recipients’ bodies, in order to enable them to resist this immune response. In the past, American scientists managed to keep specially engineered pigs hearts alive in baboons for over two years, although the primates were also given immunosuppressants, just to make sure the procedure was a success. When they came off these drugs, however, the pig hearts were instantly destroyed.
Yet this latest attempt at xenotransplantation raises new hope that it may one day be possible to transplant animal organs into humans. The heart was harvested from a pig named Mideumi, which was genetically modified back in 2010 in order to produce excessive amounts of a membrane protein that the researchers hoped would protect it from the macaque’s immune response.
So far, the experiment has been an unprecedented success, according to reports by the Yonhap news agency. As well as receiving a heart, the monkey was also given a cornea from the pig’s eye, and appears to have tolerated both organs well.
Researchers at NIAS now say they want to try transplanting pancreatic islets – which secrete insulin – into monkeys, as part of an effort to develop new treatments for diabetes in humans.