US surgeons successfully test pig kidney transplantation in a human patient

Article content

NEW YORK – For the first time, a pig kidney has been transplanted into a human without triggering immediate rejection of the recipient’s immune system, a potentially important advance that could eventually help alleviate a severe shortage of human organs for transplantation.

Article content

The procedure performed at NYU Langone Health in New York City involved the use of a pig whose genes had been altered so that its tissues no longer contained a molecule known to trigger almost immediate rejection.

The recipient was a brain-dead patient with signs of kidney dysfunction whose family consented to the experiment before her life support was removed, the researchers told Reuters.

For three days, the new kidney attached itself to her blood vessels and was kept outside her body, allowing the researchers to access it.

The results of the transplanted kidney function tests “looked pretty normal,” said Dr. Robert Montgomery, a transplant surgeon, who led the study.

The kidney produced “the amount of urine you would expect” from a transplanted human kidney, he said, and there was no evidence of the early and vigorous rejection seen when unmodified pig kidneys are transplanted into nonhuman primates.

Article content

The recipient’s abnormal creatinine level, an indicator of poor kidney function, returned to normal after transplantation, Montgomery said.

In the United States, about 107,000 people are currently waiting for organ transplants, including more than 90,000 waiting for a kidney, according to the United Network for Organ Sharing. Waiting times for a kidney average three to five years.

Researchers have been working for decades on the possibility of using animal organs for transplants, but have been hampered on how to prevent immediate rejection by the human body.

Montgomery’s team theorized that deleting the pig’s gene for a carbohydrate that triggers rejection, a sugar or glucan molecule, called alpha-gal, would avoid the problem.

Article content

The genetically altered pig, called GalSafe, was developed by the Revivicor unit of United Therapeutics Corp. It was approved by the US Food and Drug Administration in December 2020, for use as a food for people with a meat allergy. and as a potential source of human therapeutics.

Medical products developed from pigs would still require specific FDA approval before being used in humans, the agency said.

Other researchers are considering whether GalSafe pigs can be sources of everything from heart valves to skin grafts for human patients.

The New York University kidney transplant experiment should pave the way for trials in patients with end-stage renal failure, possibly in the next year or two, said Montgomery, himself a heart transplant recipient. Those trials could test the approach as a short-term solution for critically ill patients until a human kidney is available, or as a permanent graft.

Article content

The current experiment involved a single transplant and the kidney was left in place for only three days, so any future trials are likely to uncover new barriers that will need to be overcome, Montgomery said. Participants would likely be patients unlikely to receive a human kidney and a poor prognosis on dialysis.

“For many of those people, the death rate is as high as for some cancers, and we don’t think twice about using new drugs and doing new trials (in cancer patients) when it could give them a couple more months to live.” Montgomery said.

The researchers worked with medical, legal and religious ethicists to examine the concept before asking a family for temporary access to a brain-dead patient, Montgomery said.