New York surgeons removed a pig kidney less than two months after transplanting it into Lisa Pisano, a 54-year-old woman with kidney failure who also needed a mechanical heart pump. The team behind the transplant says there were problems with the heart pump, not the pig kidney, and that the patient is in stable condition.
Pisano was facing heart and kidney failure and required routine dialysis. He was ineligible to receive a traditional heart and kidney transplant from a human donor due to several chronic medical conditions that reduced the likelihood of a good outcome.
Pisano first received a heart pump at NYU Langone Health on April 4, followed by the pig kidney transplant on April 12. The heart pump, a device called a left ventricular assist device or LVAD, is used in patients who are waiting for a heart transplant or are otherwise not a candidate for a heart transplant.
In a statement provided to WIRED, Pisano’s medical team explained that they electively removed the pig kidney on May 29 (47 days after the transplant) after several episodes in which the heart pump was unable to pass enough blood through of the transplanted kidney. Constant blood flow is important so the kidney can make urine and filter waste. Without it, Pisano’s kidney function began to deteriorate.
“Overall, the kidney was no longer contributing enough to justify continuation of the immunosuppression regimen,” Robert Montgomery, director of the New York University Langone Transplant Institute, said in the statement. Like traditional transplant patients, Pisano needed to take immunosuppressive medications to prevent his immune system from rejecting the donated organ.
The kidney came from a pig genetically modified by the Virginia biotechnology company Revivicor to lack a gene responsible for the production of a sugar known as alpha-gal. In previous studies at NYU Langone, researchers found that removing this sugar prevented immediate organ rejection when transplanted into brain-dead patients. During Pisano’s surgery, the donor pig’s thymus, responsible for “educating” the immune system, was also transplanted to reduce the likelihood of rejection.
A recent biopsy showed no signs of rejection, but Pisano’s kidney was injured due to lack of blood flow, according to the statement. The team plans to study the explanted pig kidney to learn more.
Pisano has returned to dialysis, a treatment for patients with kidney failure, and his heart pump continues to work. She would not have been a candidate for the heart pump if she had not received the pig kidney.
“We hope Lisa returns home to her family soon,” Montgomery said, calling Pisano a “pioneer and hero in the effort to create a sustainable option for people awaiting an organ transplant.”
Pisano was the second living person to receive a kidney from a genetically modified pig. The first, Richard Slayman of Massachusetts, died in May just two months after the historic transplant. The surgery took place on March 16 at Massachusetts General Hospital. In a statement issued on May 11, the hospital said it had “no indication” that Slayman’s death was the result of the pig kidney transplant. The donor pig used in Slayman’s procedure had a total of 69 different genetic edits.
The global shortage of donor organs has led researchers, including teams at New York University and Massachusetts, to explore the possibility of using pigs as an alternative source. But the body immediately recognizes porcine tissue as foreign, so scientists are using gene editing in an effort to make pig organs more like humans to the immune system. How many genetic edits will be necessary for pig organs to continue functioning in people is a topic of much debate.
Pig heart transplants have also been performed on two people, one in 2022 and the other in 2023, at the University of Maryland. In both cases, the patients were ineligible for humans. Those donor pigs had 10 genetic edits and were also bred by Revivcor. Both recipients died approximately two months after their transplants.