Surgeons transplant pig kidneys into a patient, a medical milestone
Surgeons in Boston have transplanted a kidney from a genetically engineered pig into a sick 62-year-old man, the first procedure of its kind. If successful, the breakthrough will offer hope to hundreds of thousands of Americans whose kidneys are failing.
So far the signs are promising. The new kidney began producing urine shortly after surgery last weekend and the patient’s condition continues to improve, according to doctors at Massachusetts General Hospital, known as Mass General. He is already walking the halls of the hospital and may be discharged soon.
The patient is a black man, and the procedure may have special significance for black patients, who suffer a lot from end-stage kidney disease.
A new source of kidneys “could solve a persistent problem in the field – minority patients’ inadequate access to kidney transplants,” said Dr. Winfred Williams, deputy chief of nephrology at Mass General and the patient’s primary renal physician.
If kidneys from genetically modified animals can be transplanted on a large scale, dialysis “will become obsolete,” said Dr. Leonardo V. Riella, medical director of kidney transplantation at Mass General. The hospital’s parent organization, Mass General Brigham, developed the transplant program.
More than 800,000 Americans suffer from kidney failure and require dialysis, a procedure that filters toxins from the blood. Well over 100,000 people are on a waiting list to receive a transplanted kidney from a living or dead human donor.
In addition, tens of millions of Americans have chronic kidney disease, which can lead to organ failure.
While dialysis keeps people alive, the gold standard treatment is an organ transplant. However, thousands of patients die every year while waiting for a kidney because there is an acute shortage of organs. Only 25,000 kidney transplants are performed annually.
Xenotransplantation – the implantation of an organ from an animal into a human – has been proposed for decades as a possible solution that could make kidneys much more widely available. But the human immune system rejects foreign tissue, causing life-threatening complications, and experts note that long-term rejection can occur even if the donors are a good match.
In recent years, scientific developments including gene editing and cloning have brought xenotransplants closer to reality, making it possible to modify animal genes to make the organs more compatible and less likely to be rejected by the immune system.
The kidney came from a pig developed by the biotech company eGenesis, which removed three genes involved in possible rejection of the organ. In addition, seven human genes were inserted to increase human compatibility. Pigs carry retroviruses that can infect humans, and the company has also inactivated the pathogens.
In September 2021, surgeons at NYU Langone Health in New York attached a genetically modified pig kidney to a brain-dead man and watched as it began to function and produce urine. Shortly afterwards, scientists at the University of Alabama at Birmingham announced that they had performed a similar procedure with similar results.
Surgeons at the University of Maryland have twice transplanted hearts from genetically modified pigs into patients with heart disease. While the organs functioned and the first did not appear to be rejected, both patients, who were in advanced stages, died shortly afterwards.
(Patients who agree to these groundbreaking experimental treatments are usually extremely ill and have few options; often they are too sick to qualify for the waiting list for a precious human organ or are ineligible for other reasons.)
Boston transplant patient Richard “Rick” Slayman, supervisor of the state transportation department, had suffered from diabetes and high blood pressure for many years and had been under treatment at Mass General for more than a decade.
After his kidneys failed, Mr. Slayman was on dialysis for seven years and finally received a human kidney in 2018. But the donated organ failed within five years and he developed other complications, including congestive heart failure, Dr. Williams said.
When Mr. Slayman resumed dialysis in 2023, he experienced serious vascular complications — his blood vessels clotted and failed — and required repeated hospitalizations, Dr. Williams said.
Mr. Slayman, who continued to work despite his health problems, had to wait a long time for a new human kidney, and “he became despondent,” said Dr. Williams. “He said, ‘I just can’t go on like this. I can’t keep doing this.’ I started thinking about extraordinary measures we could take.”
“He would have to wait five to six years for a human kidney. He couldn’t have survived,” added Dr. Williams added.
When Dr. Williams asked Mr. Slayman about receiving a pig kidney, Mr. Slayman had many questions, but ultimately decided to go ahead.
“I saw it not only as a way to help me, but also as a way to provide hope to thousands of people who need a transplant to survive,” he said in a statement released by Mass General.
Mr. Slayman’s new kidney appears to be functional so far and he has been able to stop dialysis. In addition to creatinine, the new pig kidney also produces urine, a waste product.
Other measures are also improving daily, his doctors said. Doctors will continue to monitor Mr. Slayman for signs of organ rejection.
“He looks like himself. It’s remarkable,” said Dr. Williams.
The four-hour operation was performed by a team of surgeons including Dr. Tatsuo Kawai, director of the Legorreta Center for Clinical Transplant Tolerance at Mass General, and Dr. Nahel Elias.
The procedure was performed under a Food and Drug Administration protocol known as a compassionate use provision, which is granted to patients with life-threatening illnesses who may benefit from an unapproved treatment. Under the protocol, new drugs were also used to suppress the immune system and prevent rejection of the organ.
“He is remarkably brave for coming forward,” said Dr. Williams about Mr. Slayman. “Hats off to him. He makes an enormous contribution.”