The kidney produced “the amount of urine you’d expect from a transplanted human kidney,” said Montgomery. There was no evidence of the violent, early rejection observed in unmodified pig kidney transplantation into non-human primates.
The recipient’s short-term abnormal creatinine level, which is an indicator of poor kidney function, returned to normal after the transplant. Researchers have been working for decades on the possibility of using animal organs for transplants – previously this was prevented by the immediate rejection by the human body.
Montgomery’s team believed that turning off the pig’s gene for a carbohydrate that triggers rejection would prevent the problem. It is a sugar molecule (glycan) called alpha-gal.
The genetically modified pig named GalSafe was developed by the Revivicor unit of United Therapeutics Corp. (UTHR.O) developed. It was approved by the U.S. Food and Drug Administration in December 2020 as a food for people with a meat allergy and as a potential source of human therapeutics.
NYU’s kidney transplant experiment is set to pave the way for studies in patients with end-stage kidney failure, possibly in the next year or two, said Montgomery, a heart transplant recipient himself.
These studies could test the approach as a short-term solution for severely ill patients until a human kidney is available, or as a permanent transplant.
Seriously ill patients
Participants in similar experiments would likely be patients with a low chance of receiving a human kidney and a poor prognosis on dialysis. In the future, heart valves and skin grafts from GalSafe pigs could also be used for human patients.
“Many of these people have the same mortality rate as some cancers, and we don’t think twice about using new drugs and doing new studies (in cancer patients) if that could give them a few months,” said Montgomery.
The researchers worked with medical ethicists, lawyers, and religious experts to review the concept before asking a family for temporary access to a brain-dead patient, Montgomery said.