Chinese doctors said they transplanted a genetically modified pig liver into a 71-year-old man, who survived for 171 days after the operation, with the pig organ in place for 38 days — this is the first time such an event has been published in a peer-reviewed journal.
The doctors from the First Affiliated Hospital of Anhui Medical University transplanted a pig's liver into a 71-year-old man in May 2024
Scientists have had early success in transplanting genetically modified pig kidneys and hearts into humans, and pig livers have also been transplanted into brain-dead people. However, experts in the field of xenotransplantation have some concerns about whether the liver is a good candidate for such surgery. Xenotransplantation refers to the use of animal organs in the human body.
"Everyone says, 'Oh, compared to the heart or kidney, the liver is too complex to be transplanted,' but after that, I think people will have a different view in the future. I believe if we can get enough human genes in pigs, the liver is good," said Dr. Sun Beicheng, director of the First Affiliated Hospital of Anhui Medical University and co-author of the new study.
Unlike the more functionally narrow heart and kidneys, replacing the liver with a pig organ is more complex because it is large, has a dual blood supply, and performs multiple functions. The liver filters the blood, removes toxins and waste, processes nutrients, detoxifies harmful substances like alcohol and drugs, produces bile to help digestion, produces proteins that help blood clot, and plays an important role in regulating blood sugar.
Last year, doctors at the Perelman School of Medicine used gene-edited pig organs for the world's first known successful ex vivo liver perfusion. The blood of a brain-dead patient was circulated through a pig liver outside the body. In this case, the pig liver showed no signs of inflammation for 72 hours during testing, and the patient's body remained stable.
In March 2024, the transplanted pig liver of a brain-dead patient in China was removed after 10 days of surgery at the request of the family. There were no signs of immune rejection or accumulation of inflammation.
Experts say that the new study published in the Journal of Hepatology on Thursday shows that pig livers may serve as a bridge, helping people with severe liver disease live long enough for their own liver to recover or for a donor human liver to become available.
"In the future, maybe the left side can gain a real chance of regeneration, in which case we would remove the graft, which is sufficient to support life, or at least we know we can wait one or two months for a human graft to save his life. I think this is a very significant discovery," said Sun.
Over 100,000 people in the United States are waiting for organ transplants, and more than 9,000 are waiting for a liver transplant. The demand for human organs far exceeds the supply. According to data from the U.S. Agency for Healthcare Research and Quality, the liver is the second most in-demand organ after the kidney. For decades, scientists have been exploring alternative methods, including using pig organs, since they are similar to human organs.
The researchers said that on the tenth day after the surgery, there were no signs of acute rejection in the man's body. Instead, the remaining part of the man's liver seemed to perform better than before the surgery. Ultrasound showed normal blood flow in the portal vein, hepatic artery, and hepatic vein of the transplanted pig liver.
However, by day 25, the patient's heart began to show signs of progressive stress. Tests on days 28 and 33 showed inflammatory changes related to the transplant, and doctors changed some immunosuppressive drugs. However, there were other signs that the transplant was not as effective as initially, indicating that the man developed a condition called
xenotransplantation-associated thrombotic microangiopathy, in which small clots damage small blood vessels and organs.
On day 37, the man's blood pressure dropped suddenly, and his heart rate increased. He became intermittently unconscious. At that time, his own liver was considered capable of maintaining the body's function, so the pig organ was removed on day 38. Later, the man's liver continued to function normally.
On day 135, the patient experienced upper gastrointestinal bleeding, and died 171 days after the transplant due to bleeding.
The authors of the study said that this research provided them with insights into the challenges and feasibility of this transplantation. They wrote that the study demonstrates that pig-to-human liver transplantation "can provide effective liver support while preserving part of the natural liver, confirming its clinical feasibility as a bridging strategy."
Dr. Heiner Wedemeyer, head of the Department of Gastroenterology, Hepatology, Infectious Diseases and Endocrinology at Hannover Medical School, and professor, wrote that the experiment showed "reasons for cautious optimism" and "reminded people how far the field still has to go."
"This is really groundbreaking," Wedemeyer told CNN. "As a liver transplant specialist, this really opens up new perspectives and ideas for me."
Wedemeyer said he saw a patient with acute liver failure on Wednesday morning, who did not meet the criteria for human organ transplantation due to some cancer issues.
"If I used a pig liver to help her at this stage — because she might need three, four, five, six, seven weeks to recover her own liver — I would do it. A pig liver gives us a brand-new opportunity, which is really promising for our patients," he said.
Original article: https://www.toutiao.com/article/7559402934031663657/
Statement: This article represents the views of the author. Please express your opinion below using the [up/down] buttons.