A pig kidney transplanted into a brain-dead man continued to function for two months, marking the longest time a non-human organ has survived in a human.
The procedure, conducted on July 14, implanted the kidney in 58-year-old Maurice ‘Mo’ Miller, whose body was donated by his family after he was declared dead by neurologic criteria and maintained with a beating heart on ventilator support.
The experiment concluded Wednesday when doctors removed the genetically modified organ, and Miller’s sister said her final goodbyes.
‘I’m so proud of you,’ Mary Miller-Duffy said in a tearful farewell at her brother’s bedside.
Surgeons at NYU Langone Health, who performed the experiment, determined no differences in how the pig kidney reacted to human hormones, excreted antibiotics or experienced medicine-related side effects.
It is the latest in a string of developments renewing hope for animal-to-human transplants, or xenotransplantation, after decades of failure as people’s immune systems attacked the foreign tissue.
A previous attempt saw the organ only last for 72 hours before it was rejected.
The experiment was carried out on 58-year-old Maurice ‘Mo’ Miller, whose body was donated by his family after he was declared dead by neurologic criteria and maintained with a beating heart on ventilator support
The pig kidney underwent a single-gene modification – a sugar molecule on the surface of pig cells that can trigger the human immune system to attack pig organs
Dr Jeffrey Stern, involved with the research, said: ‘It looks beautiful, it’s exactly the way normal kidneys look.’
The statements were made after removing the kidney for a closer examination.
Dr. Robert Montgomery, the transplant surgeon who led the experiment, told The Associated Press: ‘It’s a combination of excitement and relief.
‘Two months is a lot to have a pig kidney in this good a condition. That gives you a lot of confidence’ for the next attempts.’
Montgomery, himself a heart transplant recipient, sees animal-to-human transplants as crucial to ease the nation’s organ shortage.
More than 100,000 people are on the national waiting list, most of whom need a kidney, and thousands will die waiting.
Montgomery has performed transplant surgeries thousands of times – but always on humans with human organs.
‘Somewhere in the back of your mind is the enormity of what you’re doing … recognizing that this could have a huge impact on the future of transplantation,’ Montgomery said.
Surgeons removed the pig kidney (pictured) on Wednesday, finding that it was still in great condition
The next steps: Researchers took about 180 tissue samples- from every major organ, lymph nodes, and digestive tract –- to scour any hints of problems due to the xenotransplant.
Experiments in the deceased cannot predict that the organs will work the same in the living, cautioned Karen Maschke, a research scholar at the Hastings Center helping develop ethics and policy recommendations for xenotransplant clinical trials.
The mission began in the early morning of July 14 when Drs Adam Griesemer and Jeffrey Stern flew hundreds of miles to a facility where Virginia-based Revivicor houses genetically modified pigs to retrieve kidneys lacking a gene that would trigger immediate destruction by the human immune system.
Then, the team raced to New York just as Montgomery removed Miller’s kidneys.
One of the animal’s organs was used in the experiment, and the other was stored away for comparison when the investigation comes to a close next month.
Toby Coates, Professor of Medicine at the University of Adelaide and not involved in the experiment, said: ‘This case represents one of the first functional kidney transplants from a pig into a human, and shows proof of principle that organs from a genetically modified animal can replace human kidney function for one week without rejection and using conventional kidney transplant drug therapy.
‘I’m so proud of you,’ Mary Miller-Duffy (right) said in a tearful farewell at her brother’s bedside.
Pictured is Miller as a child with his sister Mary
‘The key advance here is the genetic removal of four pig genes that have previously proven a barrier to successful cross-species transplantation, and insertion of six human genes that prevent coagulation and ‘humanize’ the pig kidney to look more human-like (the 10 genes modified pig donor). ‘
In 2022, about 26,000 people received a kidney transplant. Meanwhile, nearly 808,000 people in the U.S. have end-stage renal disease.
These statics likely helped convince Miller’s family to donate his body, as they were initially reluctant.
‘I struggled with it,’ his sister, Mary Miller-Duffy, told the AP. But he liked helping others and ‘I think this is what my brother would want. So I offered my brother to them.’
‘He’s going to be in the medical books, and he will live on forever,’ she added.