Two kidneys transplanted into human from genetically-modified pig in world-first operation

Two kidneys from a genetically-modified pig have been transplanted into the body of a human.

The transplanted organs were able to carry out the functions of kidneys once in the human body, scientists from the University of Alabama said.

They filtered blood, produced urine, were not immediately rejected, and were still working until 74 hours later.

Jim Parsons, the 57-year-old transplant recipient, was brain-dead and being kept alive on a ventilator.

The world-first has raised hopes that transplants from one species to another - xenotransplantation - could address the global shortage of donor organs, according to the study's lead surgeon Dr Jayme Locke.

"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."

She added: "The concept of being able to have an organ waiting on the shelf, waiting for the person who needs it, is just remarkable to think about - and exciting for that person."

The next step is a clinical trial on living humans with serious kidney problems.

Researchers have been trying since the early 2000s to genetically modify pigs in a way that reduces the chance of the transplant being rejected.

Pig kidneys are a similar size to human kidneys and the transplant was conducted in a similar way.

Mr Parsons had been registered as an organ donor before his death but his organs were not suitable for donation.

His family allowed him to be kept on a ventilator to keep his body functioning during the study.

Mr Parsons' ex-wife, Julie O'Hara, said the family had made a unanimous decision that he would have wanted to help as many people as possible.

She said: "Jim would have wanted to save as many people as he could with his death, and if he knew he could potentially save thousands and thousands of people by doing this, he would have had no hesitation.

"Our dream is that no other person dies waiting for a kidney, and we know that Jim is very proud that his death could potentially bring so much hope to others."

The average wait for a kidney transplant in the UK is two-and-a-half years and a patient dies every day waiting for a willing and suitable donor.

There are about 3,000 kidney transplants every year.

The new study is published in the American Journal of Transplantation.