Surgeons at the New York University’s Langone Transplant Institute have once again transplanted a kidney from a genetically modified pig onto a human, an institutional press release said. The second surgery follows less than two months after the procedure was attempted for the very first time.

More than 90,000 people in the U.S. are on the waitlist for a kidney transplant that could potentially save their lives, the press release added. To reduce these wait times, Virginia-based Revivicor has turned to xenotransplantation – using organs from a different species to meet human requirements. The company uses genetic engineering to make little changes in the donor species so that the transplant does not get rejected by the human body. 

Their offering, the GalSafe pig does not produce a sugar called alpha-galactose that is also absent in the human body. If detected in the human body, the immune system takes it as a sign of the presence of foreign material and launches an attack on the tissue that produces it. Since the transplanted organ does not contain this sugar, the human immune system is more accepting of the transplant. 

Earlier in October, the team had successfully tested this procedure on a dead recipient and have now recently repeated it on another deceased patient who remained on a ventilator, the press release said. This time as well, the kidney was attached outside of the donor’s body and observed for a period of 54 hours. During this time, urine production and creatinine levels remained within normal limits and no signs of rejection were observed. 

Although this might seem like a wasteful repetition of an experiment conducted just a couple of months ago, it is the way science works. Testing whether what you have achieved once can be achieved again. As inspiring as these findings are, they’re still preliminary findings and there is a long way to go before human trials, the lead surgeon of the procedure Robert Montogomery, MD, said in the press release. 

The team will carry out further replicating studies to determine if its method works satisfactorily before becoming a valuable tool in saving thousands of lives every year.