Richard “Rick” Slayman, the first person to receive a kidney from a genetically modified pig, died almost two months after the transplant. He was 62 years old.
The historic procedure took place on March 16 at Massachusetts General Hospital. in a statement issued on May 11The hospital said it had “no indication” that Slayman’s death was a result of the pig kidney transplant.
Slayman had previously received a kidney from a human donor in 2018, but it began to fail in 2023. He was a candidate for another human kidney transplant, but due to a shortage of available organs, he likely would have waited years to receive one. Kidneys are the most needed donated organs: almost 90,000 people in the United States alone are waiting to receive one. For decades, researchers have been interested in the idea of using animal organs to address this problem.
Slayman’s doctors suggested a pig kidney transplant after months of dialysis complications. In dialysis, a machine is connected to a major blood vessel to remove waste and excess fluid when the kidneys have stopped working. But Slayman’s blood vessels continued to clot and fail, putting him in the hospital regularly and significantly affecting his quality of life.
Until then, pig kidney transplants had only been tested in recently deceased individuals. Slayman was the first living person to receive one. “I saw it not only as a way to help myself, but also as a way to provide hope to the thousands of people who need a transplant to survive,” Slayman said in a hospital statement in March.
At a press conference on March 21, Slayman’s surgical team reported that the kidney had begun to function normally shortly after its placement. However, about a week after the transplant, doctors noticed initial signs of rejection. They were able to quickly treat Slayman with medication to counteract this, and he later did so well that he was released from the hospital. No further details are known about Slayman’s condition after his discharge. When contacted by WIRED, a Massachusetts General spokesperson said the hospital could not provide any other information at this time.
A second living person, Lisa Pisano, 54, received a genetically modified pig kidney last month. That surgery, which also included transplanting the pig’s thymus, was performed at NYU Langone Health.
Transplanting organs from one species to another is known as xenotransplantation. The main obstacle in using pig organs in humans is the human immune system, which recognizes animal tissue as foreign and rejects it.
To address this incompatibility, scientists have turned to genetic engineering. In Slayman’s case, surgeons used a pig with 69 genetic edits, created by eGenesis, a biotechnology company in Cambridge, Massachusetts. The edits removed harmful porcine genes and added certain humans.
In the New York case, Pisano received a kidney from a pig with a single gene edit, produced by Revivicor in Virginia. Instead, his doctors rely on implanting the pig’s thymus, an organ that is part of the immune system, to help prevent rejection. Patients who receive pig transplants will also need to take immunosuppressive medications for the rest of their lives to reduce the risk of rejection.
In 2022 and 2023, surgeons at the University of Maryland attempted to transplant hearts from genetically modified pigs into two patients who were not suitable to receive human hearts. In these cases, pigs with 10 genetic edits were used. Both individuals died approximately two months after their transplants.
In a statement released by Mass General, Slayman’s family said they are comforted by the optimism he provided to other patients waiting for a transplant. “Her legacy will inspire patients, researchers and healthcare professionals everywhere,” they said.