Pig Liver Transplant Breakthrough
Genetically modified pig liver kept a man alive while he awaited human organ transplant — a major xenotransplantation milestone. This advancement could transform transplant medicine for patients facing long waits for human organs.
The groundbreaking procedure took place at the First Affiliated Hospital of Anhui Medical University in China, where a 71-year-old man with liver cancer received the auxiliary transplant. The patient was not eligible for a conventional human liver transplant due to his illness. This represented the first time a genetically modified pig liver was transplanted into a living human for therapeutic purposes. The pig liver wasn't a full replacement but an "auxiliary" organ, attached to the man's own liver to provide support after a large tumor was removed. The goal was for the pig liver to act as a bridge, allowing the patient's remaining liver tissue to regenerate or to provide time until a human organ might become available. The donor was a Diannan miniature pig, chosen for its organ size compatibility with humans. The pig's liver underwent 10 genetic modifications to make it more compatible with the human body and to prevent rejection. These edits included "knocking out" three pig genes that would cause a rapid immune response and inserting seven human genes to improve immune acceptance and prevent blood clotting. For the first 31 days, the transplanted pig liver functioned effectively, producing bile and showing no signs of rejection. However, on day 38, the patient developed a serious clotting complication known as xenotransplantation-associated thrombotic microangiopathy, which necessitated the removal of the pig liver. Although the pig liver was removed, the patient survived for a total of 171 days after the initial surgery. His death was ultimately caused by recurrent gastrointestinal bleeding. The extended period of survival is considered a significant milestone, demonstrating the potential of xenotransplantation. This single case highlights the immense challenge of organ shortages. In the U.S. alone, over 103,000 people are on the national transplant waiting list, with more than 9,700 waiting specifically for a liver as of the end of 2023. In 2023, a record 10,660 liver transplants were performed in the U.S., but the gap between supply and demand remains vast.
