A genetically edited pig kidney has been successfully transplanted into a living human, marking another first in organ transplant history. The 62-year-old man was living with end-stage kidney disease when surgeons from the Massachusetts General Transplant Center performed the four-hour surgery March 16.

Doctors say the patient, Richard “Rick” Slayman, of Weymouth, Massachusetts, is doing well and is likely to be discharged from the hospital soon. The director of the center, Dr. Joren C. Madsen, hailed Slayman as a “beacon of hope” for other patients waiting for a kidney transplant, noting his “courage and willingness to embark on a journey into uncharted medical territory.”

It was Slayman’s second kidney transplant. After his kidney failed due to damage from Type 2 diabetes and high blood pressure and years of dialysis, he received a kidney from a deceased donor in 2018. The kidney began failing about five years later and he again relied on dialysis, but kept having complications, according to his doctors. Because of clotting and other problems common with dialysis, he was undergoing de-clotting and surgical revisions every two weeks.

According to an announcement from Massachusetts General Hospital, the kidney required 69 different genomic edits to make it acceptable for human transplant. The operation was performed “under a single FDA Expanded Access Protocol — known as compassionate use — granted to a single patient or group of patients with serious, life-threatening illnesses or conditions to gain access to experimental treatments or trials when no comparable treatment options of therapies exist.” The patient was also given injections of novel immune-suppressing drugs provided by two pharmaceutical companies, Eledon and Alexion.

Boosting transplant possibilities

The innovative surgery is yet another milestone for the Mass General Brigham health system, which did the world’s first successful human organ transplant — also a kidney — back in 1954 at Brigham and Women’s Hospital.

Per the release, “The pig kidney was provided by eGenesis of Cambridge, Massachusetts, from a pig donor that was genetically edited using CRISPR-Cas9 technology to remove harmful pig genes and add certain human genes to improve its compatibility with humans. Additionally, scientists inactivated porcine endogenous retroviruses in the pig donor to eliminate any risk of infection in humans. Over the past five years, MGH and eGenesis have conducted extensive collaborative research, with the findings published in Nature in 2023.”

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Transplanting organs between species is called xenotransplantation and the hope is it will open the door to more organ availability when someone needs a transplant. The National Kidney Foundation said that 123,000 Americans have passed through batteries of tests and been placed on waiting lists for an organ, including more than 101,000 who need a kidney. Many never receive one.

A need for organ donors

The list waiting for a kidney is the longest and research published in the Journal of the American Society of Nephrology predicts the need for those with end-stage kidney disease will increase as much as 68% by 2030.

According to the National Kidney Foundation, 17 people a day die waiting in the U.S.

That’s despite innovations in the field of kidney transplantation, including “chains,” where someone has a willing donor who is not a match but could donate to someone else who has a donor who is not their match. Some of those chains involve many pairs of willing donors and their not-a-match recipients who could help someone else, creating the chain of transplants.

The American Journal of Transplantation reported that in 2021, 25,488 kidneys were transplanted in the U.S., just under 6,000 of them from living donors. A human just needs one healthy working kidney.

“Seventy years after the first kidney transplant and six decades following the advent of immunosuppressive medications, we stand on the brink of a monumental breakthrough in transplantation. At MGH alone, there are over 1,400 patients on the waiting list for a kidney transplant. Some of these patients will unfortunately die or get too sick to be transplanted due to the long waiting time on dialysis. I am firmly convinced that xenotransplantation represents a promising solution to the organ shortage crisis,” said Dr. Leonardo V. Riella, who is medical director over kidney transplants at the transplant center.

Harvard News reported that “of the estimated 36 million people in the U.S. affected by chronic kidney disease, some 800,000 have end-stage kidney disease or kidney failure, a terminal condition that requires either a new kidney or painful, prolonged dialysis sessions that filter waste from the blood and can last several hours at a time, several times a week.”

Per the article, “Safely transplanting organs from animals into humans requires multiple steps to minimize the risk of the recipient’s immune system rejecting the new organ — also a concern with human organ transplants — and to prevent infection and other complications.”