Organ transplantation is one of the most incredible breakthroughs in 20^th-century medicine. However, the sad truth is that there simply aren’t enough organs to meet demand. In the US alone, more than 10,000 patients are waiting for a liver transplant, and their doctors desperately search for ways to give them more time until the right organ becomes available. Now, a successful experiment with a pig’s liver could lead to a creative new solution.

Scientists from the Perelman School of Medicine at the University of Pennsylvania just announced the successful perfusion of a pig’s liver using blood from a recently deceased human donor. It’s hoped that this idea could be developed into what they’ve called a “bridge” for critically ill patients – a kind of transplant halfway house, to keep them going until a human liver is found.

“Any time a patient dies while waiting for a transplant, it is a tragedy, and we are always working to develop new ways to extend their lives,” said study lead Dr Abraham Shaked in a statement. “The success of the first part of our study is significant for those facing liver failure, offering a glimpse into a future where innovative solutions can bring hope to patients who might otherwise be destined to die while waiting for a transplant.”

For the experiment, which took place last December, the donor’s circulatory system and breathing were artificially maintained after medics had confirmed brain death. Their organs were not deemed suitable for donation to patients on the transplant waiting list, but their family generously agreed to allow their body to be used for this procedure.

Perfusion refers to the process of circulating blood through an organ. The donor’s own liver was kept in place throughout – this is not the same as xenotransplantation, true animal-to-human transplants. Instead, the pig liver, which was genetically engineered to minimize the chances of rejection, was hooked up to the donor’s circulatory system from outside their body.

The donor’s blood was circulated through the pig liver, bypassing their own liver. They were monitored for 72 hours, during which time there was no inflammation observed in the liver and no issues with the donor’s body.

Waiting times for people on the liver transplant list can stretch as long as 5 years. There is currently no way to replace the function of the liver with a machine, such as can be done with dialysis for the kidneys, so patients with liver failure really have no option other than a transplant. If this perfusion approach proves safe and feasible, it could help keep the sickest patients alive for a vital window of time, maximizing their chances of getting a transplant.

There’s also potential for it to be used as a temporary treatment for people healing from liver injuries, in a similar way to extracorporeal membrane oxygenation (ECMO) for the heart and lungs.

“Our system combined with a genetically modified liver combines modern organ perfusion technology with the functions of a whole liver, which is a potentially powerful combination that could save lives,” said Dr Peter Friend, chief medical officer of OrganOx, the company that produced the device that makes the procedure possible.

These results are only the first stage of a larger study the team is working on, with three more deceased donors. The procedure will need to be trialed in donors whose own livers have been removed to get a true sense of whether it can provide the “bridge” to transplant that the scientists are hoping for.

The team paid tribute to the kindness of the family who donated their loved one’s body for this experiment. A relative commented: “Our family is very proud to support this medical advancement and see our loved one’s legacy benefit countless others. It is a testament to our loved one’s selflessness and compassion to know this donation offers such hope for people suffering serious disease in the future.”