In what, we can call a miracle in medical science, a pig kidney was transplanted into a human without triggering any immediate rejection by the recipient's immune system.
The procedure was carried out at New York's NYU Langone Health that involved using a pig's genes which were altered so that its tissues no longer contained a molecule known to trigger an almost immediate rejection.
The recipient was a brain-dead patient with signs of kidney dysfunction whose family consented to the experiment before she was due to be taken off life support.
For three days, the new kidney was attached to her blood vessels and maintained outside her body, giving researchers access to it. The test results of the transplanted kidney's function "looked pretty normal" said the transplant surgeon Dr Robert Montgomery.
The kidney made “the amount of urine that you would expect” from a transplanted human kidney, he said, and there was no evidence of the vigorous, early rejection seen when unmodified pig kidneys are transplanted into non-human primates.
The recipient’s abnormal creatinine level – an indicator of poor kidney function – returned to normal after the transplant, Montgomery said.
Montgomery’s team theorised that knocking out the pig gene for a carbohydrate that triggers rejection – a sugar molecule, or glycan, called alpha-gal – would prevent the problem.
The genetically altered pig, dubbed GalSafe, was developed by United Therapeutics Corp’s Revivicor unit. It was approved by the US Food and Drug Administration (FDA) in December 2020, for use as food for people with a meat allergy and as a potential source of human therapeutics.
According to the United Network for Organ Sharing, there are nearly 107,000 people waiting for organ transplants, including more than 90,000 awaiting a kidney transplant.
This NYU kidney transplant should pave the way for trials in patients with end-stage kidney failure, possibly in the next year or two, said Montgomery, himself a heart transplant recipient.