US surgeons have successfully tested porcine kidney transplants in human patients

For the first time, porcine kidney was transplanted into humans without causing immediate rejection by the recipient’s immune system. This is a major advance that may ultimately help alleviate the serious shortage of human organs for transplantation.

A procedure performed at NYU Langone Health in New York City used genetically modified pigs to eliminate molecules known to cause near-immediate rejection in tissues. The recipient was a brain-dead patient with signs of kidney dysfunction, and the family agreed to the experiment before she was removed from life support, the researchers told Reuters.

For three days, a new kidney attached to her blood vessels and was maintained outside her body, giving researchers access to it. Test results for transplanted kidney function “looked fairly normal,” said Dr. Robert Montgomery, a transplant surgeon who led the study.

The kidneys produced “the amount of urine you expected” from the transplanted human kidneys, he said, and the activeness seen when unmodified porcine kidneys were transplanted into non-human primates. There was no evidence of early rejection.

Abnormal creatinine levels in the recipient, an indicator of decreased kidney function, returned to normal after the transplant, Montgomery said. According to the United Network for Organ Sharing, approximately 107,000 people are currently waiting for organ transplants in the United States, of which more than 90,000 are waiting for kidneys. The average waiting time for the kidneys is 3-5 years.

Researchers have been working on the possibility of using animal organs for transplantation for decades, but have been wondering how to prevent immediate rejection by the human body. The Montgomery team theorized that knocking out the porcine gene for a carbohydrate (a sugar molecule called alpha-gal or a glycan) that causes rejection can prevent the problem.

A genetically modified 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 meat allergies and as a potential source of human remedies.

Medical products developed from pigs require specific FDA approval before they can be used in humans, officials said.

Other researchers are investigating whether GalSafe pigs can be a source of everything from heart valves to skin grafts in human patients.

Kidney transplant experiments at the University of New York should probably pave the way for trials in patients with end-stage renal disease within the next year or two, said heart transplant recipient Montgomery. These trials may test this approach as a short-term solution for critically ill patients until the human kidney becomes available, or as a permanent graft.

According to Montgomery, the current experiment involved a single transplant and left the kidneys for only three days, which is likely to reveal new barriers that need to be overcome in future trials. Participants are probably patients who are less likely to receive human kidneys and have a poor prognosis for dialysis.

“For many, mortality is as high as some cancers, and when it can take months, we never think about using new drugs and conducting new trials (in cancer patients) again. Many lives, “said Montgomery.

According to Montgomery, researchers worked with medical ethicists, legal and religious experts to scrutinize the concept before asking families for temporary access to brain-dead patients