Doctors said the gene-edited organs functioned normally in the host body, potentially clearing the way for wider clinical trials with living patients
Surgeons in the US have announced the successful transplantation of kidneys from a genetically modified pig into a brain-dead man's body. The organs created urine for three days and showed no signs of being rejected by the host's immune system before the study concluded.
The procedure, which was described in an American Journal of Transplantation paper on Thursday, marks another step towards overcoming major challenges to human xenotransplantation, or cross-species tissue transfer. It is thought that such implants could help solve the chronic shortage of donor organs.
Doctors at the University of Alabama at Birmingham conducted the surgery on September 30 last year on Jim Parsons, a 57-year-old man who had been declared brain dead after a motorcycle accident. After removing Parsons' own kidneys while his blood was still circulating, the team inserted the pig organs. Within half an hour, they began filtering blood and producing urine.
"This game-changing moment in the history of medicine represents a paradigm shift and a major milestone in the field of xenotransplantation, which is arguably the best solution to the organ shortage crisis," lead surgeon Dr. Jayme Locke said in a statement.
"We have bridged critical knowledge gaps and obtained the safety and feasibility data necessary to begin a clinical trial in living humans with end-stage kidney failure disease," she added.
Locke also noted that it is not uncommon to use brain-dead patients for such surgeries, telling the Daily Mail that there would have been a different outcome if a healthy patient was used instead. Although the "hostile" brain death environment makes it difficult to assess typical kidney functions, she said it was a less risky way to "evaluate the safety and feasibility of the pig-to-non-human primate model."
Prior to the surgery, Parsons received immune-suppression therapy to prevent his cells from rejecting the organs, while the animal's genes were edited at 10 key points to "knock in" some six human genes while removing four pig ones. The study noted that pigs are used in such research since they are "easily bred and can have organs of similar size to humans."
Earlier this month, a Maryland man received the first-ever heart transplant from a genetically altered pig. Meanwhile, surgeons in New York successfully implanted a pig kidney into another brain-dead patient last year, but Locke said that procedure did not remove the host's kidneys.