This transplant took place at NYU Langone Hospital in New York on July 14 on a 57-year-old man who was brain dead and placed on life support following donating his body to science.
These animal-to-human organ transplants, also called xenografts, are being developed in hopes of addressing the shortage of organ donations in a country where tens of thousands of patients are on the waiting list for transplants.
These 32 days represent “the longest time a genetically modified pig kidney has worked in a human”welcomed the hospital in a press release, indicating that it plans to continue the experiment for an additional month.
The kidneys of this man, Maurice Miller, were removed during an operation and replaced with the kidney of a genetically modified pig, so that the organ would not be immediately rejected by the human organism.
The doctors also transplanted the pig’s thymus, a gland that plays an important role in the immune response. The idea is that the thymus helps the cells of the recipient to identify those of the pig as his, thus also helping to avoid rejection, explained during a press conference Dr. Adam Griesemer, involved in the operation. . The analysis of the role played by the thymus will be carried out at the end of the two months.
Anyway, for more than a month, “kidney biopsies and tests show no signs of rejection”said Dr. Robert Montgomery, director of the NYU Langone Institute of Transplantation. “The pig kidney replaces all important functions provided by a human kidney”.
According to him, this step should lead to a clinical trial on a living human.
“Unlimited Kidney Source”
Several xenografts have been performed by this team in recent years, including the world first transplant of a pig kidney into a human, in September 2021. The kidney had then worked well for a few days.
All their trials so far have been quite short, they did not allow to observe a possible rejection of the adaptive immune system, which occurs 10 to 14 days following the presence of a foreign tissue, explained Dr. Robert Montgomery .
The world’s first for a porcine heart transplant into a living human was performed by a University of Maryland hospital. But the man had died two months following his operation.
For kidney transplantation, many thought “that it would not be possible to maintain a deceased for such a long period following brain death”said Dr. Robert Montgomery on Wednesday.
The functions normally carried out by the brain – regulation of temperature, heart rate, blood pressure… – have been replaced by constant monitoring and care by a medical team.
“It was a very difficult decision to make”, said Wednesday the sister of the deceased, Mary Miller-Duffy, who agreed that the body of her brother be used for this study. But “Even though my brother cannot be there, I can confidently say that he would have been proud that the tragedy of his death helped the lives of many people.”
More than 100,000 Americans are currently on the waiting list for an organ transplant, of which nearly 88,000 are waiting for a kidney.
Unfortunately, only a third of them actually receive a donation, while the others become too ill to benefit from it or die while waiting for one, according to Dr. Robert Montgomery.
“There simply aren’t enough organs available for everyone who needs them”did he declare. “I strongly believe that xenografts are a viable way to change that.”
Since the pigs used “are not cloned, but bred, their number can be increased much more easily, in order to provide an unlimited source of kidneys for patients in need”he said.
