Researchers at the University of Alabama-Birmingham have successfully transplanted two kidneys from a genetically modified pig into a human who was brain dead.

It marks the second successful transplant of pig kidneys into a human in the United States, following a similar achievement by surgeons at NYU Langone Health in New York City last October in a procedure that also involved a brain-dead recipient, the researchers said in an article published Thursday by the American Journal of Transplantation.

On Jan. 10, surgeons in Maryland successfully transplanted a pig heart into 57-year-old Jim Parsons with life-threatening heart failure who had exhausted other treatments and did not qualify for a human heart transplant because he was not healthy enough.

Mr. Parsons was brain dead and on life support after having suffered a traumatic head injury, but scientists assessed the effects of the transplant with his family’s blessing.

Pig organs are genetically modified to prevent rejection by human recipients, as well as additional growth after surgery, the University of Alabama-Birmingham researchers said.

The ability to transplant pig organs into human recipients could increase the number of available organs and prevent thousands of deaths in the United States caused by donor organ shortages, they said.

The report of the successful transplant “provides knowledge that could not be generated in animal models and moves us closer to a future where organ supply meets the tremendous need,” co-author and surgeon Dr. Jayme E. Locke said in a press release.

Once transplanted, the kidneys produced urine and were not rejected in the short term, said Locke, who is director of transplantation at the University of Alabama-Birmingham.

Earlier this month, David Bennett become the first patient in the world to get a heart transplant from a genetically-modified pig.

The first peer-reviewed research outlining Mr. Parsons’ successful transplant by surgeons at UAB’s Department of Surgery has been published today in the American Journal of Transplantation.

‘This game-changing moment in the history of medicine represents a paradigm shift and a major milestone in the field of xenotransplantation, which is arguably the best solution to the organ shortage crisis,’ said Professor Jayme Locke, director of the Comprehensive Transplant Institute in UAB’s Department of Surgery and lead surgeon for the study.

‘We have bridged critical knowledge gaps and obtained the safety and feasibility data necessary to begin a clinical trial in living humans with end-stage kidney failure disease.

‘This study provides knowledge that could not be generated in animal models and moves us closer to a future where organ supply meets the tremendous need.’

Mr Parsons was declared brain dead – and therefore officially deceased – on September 26, prior to the procedure on September 30.

‘Circulation was maintained initially for the purposes of allocating his organs for transplant and then for our study,’ said Professor Locke.

Mr. Parsons was a registered organ donor through Legacy of Hope, Alabama’s organ procurement organisation.

He had longed to have his organs help others upon his death, but his organs were not suitable for donation.

His family permitted UAB to maintain him on a ventilator to keep his body functioning during the study.

His native kidneys were removed, and the two genetically modified pig kidneys were transplanted.

For the first time, the pig kidneys transplanted were taken from pigs that had been genetically modified with 10 key gene edits that may make the kidneys suitable for transplant into humans.