Chinese scientists achieve world’s 1st successful living pig-to-human liver transplant

In a world-first, Chinese researchers have successfully transplanted a genetically engineered pig liver into a living human, proving that a porcine graft can sustain human liver function.

The operation, performed in Hefei and published in the Journal of Hepatology earlier this month, used a Diannan miniature pig liver modified at 10 genetic sites to reduce immune rejection. The 71-year-old recipient, who had hepatitis B–related cirrhosis and liver cancer, lived for 171 days after the surgery.

The donor pig was genetically engineered to remove three antigens that trigger immune rejection and to add seven human genes that regulate complement activity, coagulation, and inflammation. Surgeons connected the auxiliary pig liver to the patient’s blood supply so it could function alongside his own liver. The graft produced bile, synthesized clotting factors and maintained stable metabolic indicators for more than a month without rejection. On day 38, it was removed after doctors detected a vascular complication which was treated successfully.

Throughout the 38-day graft period, clinical monitoring showed that the pig liver contributed to detoxification, protein synthesis and metabolic regulation typically handled by the human liver. Histological examination revealed viable hepatocytes, mild endothelial swelling and localized thrombus formation, but no signs of necrosis or acute rejection. Laboratory tests confirmed stable ammonia and bilirubin levels during graft function and no evidence of porcine endogenous retrovirus infection.

After graft removal, the patient’s native liver maintained near-normal function for several weeks before he developed gastrointestinal bleeding and died nearly six months after surgery.

The operation marked the first verified instance of a genetically engineered pig liver sustaining normal human liver function in a living patient. It demonstrated that a xenograft can perform metabolic and synthetic roles for weeks without acute rejection, a threshold not previously achieved in human subjects.

The study also provided the first detailed clinical data on immune response, vascular adaptation and genetic compatibility in a functioning liver xenotransplant. Researchers say these findings establish a foundation for refining organ engineering and immune management in future trials.