Scientific scrutiny of first pig-to-human liver transplant

A transplant of a genome-edited pig liver into a human has been described in a peer-reviewed publication for the first time.

The newly documented transplant took place at Xijing Hospital of the Fourth Military Medical University in Xi'an, China in March 2024, and has now been published in Nature. The paper documents how the research team transplanted a genome-edited pig liver into a brain-dead man, while his original liver was left in place. Throughout the ten-day study period, the transplanted liver functioned normally by circulating the patient's blood and producing bile. There were no signs of rejection and the transplanted liver remained functional and stable until the end of the study.

'Following surgery, we found that the liver collected from the gene-modified pig really functioned very well in the human body,' Dr Lin Wang, joint corresponding author told the Telegraph. 'We also monitored blood flow from the different vessels and arteries and hepatic veins, and all the blood flows were in a reasonable state and rate, so we can see the surgery was really successful… It's a great achievement because this is the first time we've unravelled whether the pig liver could function well in human bodies or potentially replace the human liver in the future.'

Prior to surgery, six genome alterations were introduced to the pig to prevent organ rejection – three genes that contribute to the production of sugars found on the surface of pig cells were deactivated, and three genes were introduced for the production of human proteins. The recipient received a daily regimen of immunosuppressive drugs and the study was terminated after ten days at the request of the recipient's family.

The study achieved its aim, which was to investigate whether the genome-edited pig liver could provide a temporary solution to patients with acute liver failure. The authors believe the temporary liver should last until a compatible human donor becomes available.

'This is an important study because it advances the field of xenotransplantation from non-human primates to human…' Professor Peter Friend, from the University of Oxford, who was not involved in the study, said. 'This is a very elegant surgical technique which allows the insertion of a (relatively small) xeno-liver with limited disruption to the anatomy of the existing liver (ie, it is potentially feasible in a clinical setting as a temporary bridging technique).

At the time of the surgery, the researchers planned to repeat the procedure in another brain-dead person, but instead aimed to remove the person's existing liver. In January 2025, the team announced to the Global Times that they had achieved their aim by completely replacing a human liver in a brain-dead person.

In January 2024, a team from the University of Pennsylvania connected a genome-edited pig liver to a brain-dead man using an external machine with tubes to carry blood (see BioNews 1223) and in May 2024, a team from the First Affiliated Hospital of Anhui Medical University, China, successfully transplanted a genome-edited pig liver into a living human recipient (see BioNews 1241).