Chinese doctors announced on Wednesday that they had successfully transplanted a genetically modified pig liver into a brain-dead human for the first time, marking a significant step toward alternative donor options for patients in need of liver transplants.
Pigs have emerged as the most viable source of animal organ transplants, with several patients in the United States already receiving pig kidneys or hearts in recent years. However, liver transplants had not been tested inside a human body until now due to the organ’s complex functions.
With a growing global demand for liver donations, researchers hope gene-edited pig livers could serve as a temporary solution for critically ill patients on long waiting lists.
Doctors from the Fourth Military Medical University in Xi’an, China, detailed the breakthrough in a study published in Nature.
On March 10, 2024, a miniature pig liver with six genetically modified genes to enhance compatibility was transplanted into a brain-dead adult at the hospital.
The patient retained their original liver, receiving what is known as an auxiliary transplant, intended to act as a “bridge organ” for patients awaiting a human donor.
Over 10 days, doctors monitored blood flow, bile production, immune response, and other key functions.
The pig liver functioned effectively, producing bile and albumin, a key protein essential for various bodily processes.
The trial was terminated after 10 days at the family’s request, with doctors emphasizing that strict ethical guidelines were followed throughout the procedure.
While the results were promising, experts stress that more research is needed before pig livers can serve as a replacement for human organs.
Unlike hearts, which primarily pump blood, livers perform multiple functions, including filtering blood, metabolizing drugs and alcohol, and producing bile.
The pig liver produced significantly lower levels of bile and albumin compared to a human liver, highlighting the need for further improvements.
Extended studies beyond 10 days are necessary to determine long-term viability.
Researchers now plan to trial the gene-edited pig liver in a living human.
Experts worldwide have praised the breakthrough while emphasizing that pig organ transplants are still in the early stages.
Oxford University transplantation professor Peter Friend described the results as “valuable and impressive”, noting that while this is not an immediate alternative to human liver transplants, it is an important step toward supporting patients with liver failure.
Lin Wang, a co-author of the study, acknowledged the contributions of US researchers, stating that China had “learned a lot from research conducted in the United States.”
Last year, scientists at the University of Pennsylvania attached a pig liver to a brain-dead patient, but unlike the Chinese transplant, the organ remained outside the body.
Meanwhile, the first two US recipients of pig heart transplants did not survive, though a 53-year-old Alabama woman, Towana Looney, is recovering well after receiving a pig kidney on November 25, 2024.
With further refinements in genetic modification and medical techniques, pig organ transplants could revolutionize the future of organ donation, offering lifesaving options for patients facing critical shortages.