American scientists have succeeded in making the kidney of a genetically modified pig work on a human, a breakthrough that represents hope for the many people waiting for a transplant.
If success is confirmed, pigs could one day be bred with the aim of providing organs (kidneys, but also lungs, hearts, etc.) to humans who need them.
The operation was carried out on September 25 at NYU Langone Hospital in New York, using the kidney of a pig that had undergone a genetic modification so that the organ was not rejected by the human body.
The kidney was not strictly speaking implanted inside a human body, but was connected to the blood vessels of a brain-dead patient, whose family had authorized the experiment, at the level of the brain. top of his leg.
The operation lasted about two hours.
The kidney “worked well” during the two and a half days of the experiment, Robert Montgomery, director of the NYU Langone Institute of Transplantation, told AFP. “He did what he was supposed to do, … he produced urine.”
Such a transplantation had already been attempted in primates – a pig kidney having then functioned for a whole year – but never yet in humans.
And for good reason: the human organism contains antibodies which attack a type of sugar normally present “on all pig cells”, which causes “immediate rejection” of the organ, explained Robert Montgomery.
But this time the animal has been genetically modified to no longer produce this sugar and there was no “rapid rejection of the kidney” observed.
Nearly 107,000 Americans are currently on the waiting list for an organ transplant, including 90,000 for a kidney. Every day, 17 people in the country who need a transplant die.
“I think people, especially those who are waiting (…), will see this as a potential miracle”, rejoiced the professor, who himself benefited from a heart transplant there. almost three years ago.
Why a pig, rather than another animal?
“Pigs are the right size, they grow quickly, and litters have lots of young,” said Robert Montgomery. “It’s also more acceptable because we already use pigs for food.”
Pig heart valves are already widely used in humans, and their skin can be used for grafts on severe burns.
After 54 hours, the kidney was still functioning perfectly and had not been rejected. But the patient’s life support was turned off, ending the experiment.
The professor admitted that these results were “limited”, in particular because of the short period of experimentation.
“What would have happened after three weeks, three months, three years remains a question,” he said. “But it is nevertheless a very important intermediate step, which tells us that a priori, at least initially, things will go well.”
According to him, larger clinical trials could begin within “a year or two”.
Some experts have greeted the news with caution, as the detailed results of the conducted study have yet to be published in a scientific journal (which is expected next month).
“It is nevertheless an interesting step on the road to the use of genetically modified pigs as a source of organs for transplants,” commented Alan Archibald, genetics specialist at the University of Edinburgh.
Xenografts – from animal to human – are not new. Doctors have attempted cross-species transplants since at least the 17th century, with the earliest experiments focusing on primates.
In 1984, a baboon heart was transplanted into a baby but the little one, nicknamed “Baby Fae”, only survived 20 days.