Chinese doctors announced on Wednesday that they had successfully transplanted a genetically modified pig liver into a brain-dead human for the first time. This marks a significant breakthrough in organ transplantation and offers hope for addressing the global shortage of donor livers.
Pigs have become the preferred animal donors for organ transplants, with several living patients in the US having received pig kidneys or hearts in recent years. However, liver transplants have been more challenging, and until now, no pig liver had been tested inside a human body.
Given the increasing demand for liver donations worldwide, researchers hope that gene-edited pigs could provide temporary support for critically ill patients on long waiting lists.
Doctors at the Fourth Military Medical University in Xi’an, China, detailed this latest advancement in a study published in the journal Nature. The team transplanted a liver from a miniature pig—genetically modified with six edited genes—into a brain-dead adult on March 10, 2024. The trial lasted for 10 days before it was ended at the request of the patient’s family, with doctors adhering to strict ethical guidelines.
A ‘Bridge Organ’
The recipient retained their original liver, undergoing an auxiliary transplant, a procedure aimed at supporting the existing liver of patients awaiting a human donor.
Throughout the 10-day observation period, doctors monitored the pig liver’s blood flow, bile production, immune response, and other key functions. The organ performed well, producing bile and the crucial protein albumin, according to Lin Wang, a co-author of the study.
“This is a remarkable achievement that could benefit patients with liver conditions in the future,” Wang stated in a press conference.
While researchers celebrated the success, they cautioned that this early experiment does not confirm whether a pig liver can fully replace a human liver. Unlike hearts, which primarily pump blood, livers perform multiple functions, including filtering toxins, breaking down drugs and alcohol, and producing bile to aid digestion.
Though the pig liver in this study produced bile and albumin, its output was significantly lower than that of a human liver, highlighting the need for further research—especially with longer study periods.
The next step for the team is to test the gene-edited pig liver in a living human patient.
‘Impressive’ Results, But More Work Needed
Peter Friend, a transplantation expert at Oxford University who was not involved in the study, praised the results as “valuable and impressive.” However, he emphasized that this approach is not yet a substitute for human liver transplants.
“This is an important step in assessing the compatibility of genetically modified livers with humans, paving the way for future applications,” Friend told AFP.
Lin also acknowledged the importance of international collaboration, particularly with researchers in the US.
“We have learned a great deal from the research conducted by American doctors,” he said.
In 2023, scientists at the University of Pennsylvania connected a pig liver to a brain-dead patient but kept the organ outside the body rather than transplanting it. Meanwhile, both US patients who received pig heart transplants ultimately passed away.
However, there has been progress in other areas—Towana Looney, a 53-year-old from Alabama, successfully received a pig kidney transplant on November 25, 2024, and has since returned home.
