First pig kidney in a human: Is this the future of transplants?

The first man to receive a genetically modified kidney transplant from a pig was discharged from hospital on Wednesday last week.

Richard “Rick” Slayman, 62, who had been suffering from end-stage kidney disease, no longer needs dialysis after the groundbreaking procedure at Massachusetts General Hospital (MGH), Harvard Medical School’s biggest teaching hospital in Boston, Massachusetts.

How did the first pig kidney transplant go?

Slayman had been diagnosed with end-stage renal disease, which means his kidneys could not function on their own. He was placed on dialysis from 2011 until 2018 when he received his first kidney transplant from a human donor at MGH.

About five years later, the transplanted kidney started showing signs of failure and, in May 2023, Slayman restarted dialysis. After this, he started experiencing complications associated with dialysis which are common among dialysis patients. Hence, he required regular hospital visits for de-clotting and surgical revisions, which affected his quality of life.

The “gene-edited” pig kidney was provided by eGenesis, a biotechnology company in Cambridge, Massachusetts which develops human-compatible engineered organs. The company removed harmful pig DNA from the pig donor using genetic editing, and added human DNA to make the kidney more compatible with the human body.

Slayman was well enough to return home just two weeks after the four-hour procedure, which took place on March 16.

Slayman called “leaving the hospital today with one of the cleanest bills of health I’ve had in a long time” one of the happiest moments of his life, in a statement released by MGH on April 3.

The procedure is an example of “xenotransplantation”: the transplantation of organs from one species to another.

The transplant was approved by the Food and Drug Administration (FDA), through a single Expanded Access Protocol, or “compassionate use”, which grants experimental treatment access to patients with life-threatening diseases.

“I want to thank anyone who has seen my story and sent well wishes, especially patients waiting for a kidney transplant. Today marks a new beginning not just for me, but for them, as well,” said Slayman.

Why does this matter?

“The procedure marks a major milestone in the quest to provide more readily available organs to patients,” MGH stated in a press release.

The success of the procedure has provided a ray of hope amid the organ shortage crisis in the United States and beyond.

At the moment, more than 103,000 people in the US are still waiting for organ transplants, according to the Organ Procurement and Transplantation Network. The network’s data also shows that 17 people in the US die every day waiting for an organ transplant.

“I am firmly convinced that xenotransplantation represents a promising solution to the organ shortage crisis,” said  Leonardo V Riella, medical director for kidney transplantation at MGH, who oversaw Slayman’s procedure.

“Although much work remains to be done, this is a major symbolic event for the entire transplant community that represents a real possibility of xenotransplantation, one day benefitting a large number of patients,” David Klassen, the chief medical officer of the United Network for Organ Sharing (UNOS), a non-profit organisation which runs a national transplant system with the US federal government, told Al Jazeera.

He added that this could begin to bridge “the gap between the need for organ transplantation and number of organs available for transplantation”.

Could interspecies organs become the norm?

More research needs to be done before organ transplants from pigs or other animals become widely available.

In January 2022, an American man named David Bennett received a gene-edited pig heart, which seemed to be functioning in his body. In March 2022, however, Bennett passed away. The exact cause of death was not released.

In September 2023, Lawrence Faucette became the second person in the US to receive a genetically modified pig heart. Six weeks later, however, he also died. The University of Maryland Medical Center, where the transplantation was performed, said the heart had begun to show signs of rejection.

The same month, however, surgeons at New York University Langone Health concluded that a gene-edited pig kidney transplant had worked normally inside a brain-dead body of a human.

“There is a risk of rejection for all organ transplants,” Klassen, the UNOS chief medical officer said.

Klassen explained that rejection is common and signs that the body is rejecting a transplanted organ are treated with adjustments to transplant medications.

“The recent xenotransplants have shown that scientists and researchers have been able to overcome the immediate rejection risk with genetically modified porcine organs,” Klassen said.

The chief medical officer of UNOS added that this procedure is based on decades of research by medical specialists.

“But there is still much left to do before it could become widely available, such as clinical trials that replicate this in a large number of patients and the study of long-term outcomes”.