China has achieved a historic breakthrough in transplant medicine by implanting a genetically engineered pig liver into a living human—marking the first time an auxiliary porcine liver has supported human metabolic function for an extended period. The pioneering xenotransplant provided crucial temporary liver support in a situation where no standard treatment path remained.
The patient, a 71-year-old man battling hepatitis B–related cirrhosis alongside advanced hepatocellular carcinoma, was ineligible for both conventional liver resection and human donor transplantation. With his condition rapidly deteriorating and no donor organ available, doctors opted for a compassionate-use xenotransplantation. On May 17, 2024, surgeons removed the tumour-bearing right lobe of his liver before implanting the engineered pig liver.
Genetically Modified Organ Designed for Human Compatibility
The transplanted liver originated from a Diannan miniature pig that had undergone ten targeted genetic changes—three deletions of xenoantigens and seven insertions of human genes—to reduce immune rejection and stabilise coagulation. Once blood flow to the graft was established, the organ began functioning immediately, producing bile and taking over essential metabolic duties including bile acid control, albumin generation, and clotting factor production.
Biopsies and early lab tests confirmed there was no hyperacute or acute rejection, and the patient’s liver and kidney functions initially remained steady.
A Serious Complication Surfaces
Despite early success, a significant complication appeared nearly a month after surgery. The patient developed xenotransplantation-associated thrombotic microangiopathy (xTMA), a life-threatening issue characterised by hemolysis, reduced platelet count, complement activation, and the formation of tiny clots in blood vessels.
Doctors attempted multiple treatments—anticoagulants, plasma exchange, and the complement-blocking drug eculizumab—but the condition persisted. On the 38th day, surgeons removed the pig liver graft. By then, the patient’s remaining native liver had regenerated enough to sustain metabolic function, and the xTMA subsided.
The patient later suffered repeated variceal bleeding and passed away on postoperative day 171.
A Scientific Milestone With Key Barriers to Overcome
Experts say the case demonstrates for the first time that a genetically engineered porcine liver can maintain human metabolic processes for weeks. However, complications such as xTMA, problems with coagulation compatibility, and complement system activation remain major hurdles.
Researchers stress that the next phase of progress will require more advanced gene-editing approaches, refined immunosuppression, and targeted prevention of xTMA before pig-to-human liver support becomes a viable clinical solution worldwide.