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New York surgeons successfully attached a kidney grown in a genetically modified pig to a human patient and discovered that the organ was functioning normally; This is a scientific breakthrough that could one day provide a huge supply of new organs for seriously ill patients.
While many questions remain to be answered about the long-term outcomes of the transplant, which involved a brain-dead patient who was followed for just 54 hours, experts in the field said the procedure represents a milestone.
Johns Hopkins School of Medicine, professor of transplant surgery, who was not involved in the study. “We need more information about the lifespan of the organ,” said Dorry Segev. Still, he said: “This is a huge breakthrough. It’s a big, big deal.”
Researchers have long tried to grow organs in pigs suitable for transplant into humans. A steady stream of organs, which may eventually include hearts, lungs, and livers, would offer a lifeline to the more than 100,000 Americans currently on transplant waiting lists, including 90,240 people who need kidneys. Every day, 12 people on the waiting list die.
Even more Americans with kidney failure – more than half a million – depend on rigorous dialysis treatments for survival. Largely due to the scarcity of human organs, the vast majority of dialysis patients are not eligible for transplants, which are reserved for those most likely to develop after the procedure.
The surgery, performed at NYU Langone Health, was first reported by USA Today on Tuesday. The research has not yet undergone peer-reviewed or published in a medical journal.
The transplanted kidney was obtained from a pig genetically modified to grow an organ that cannot be rejected by the human body. In a close approach to a real transplant procedure, the kidney was connected to a brain-dead person who was on a ventilator.
NYU Langone Transplant Institute director Dr. According to Robert Montgomery, the kidney connected to the blood vessels in the upper leg outside the abdomen began to function normally and began making urine and the waste product creatinine “almost immediately.” procedure in September.
Experts said that although the organ is not implanted in the body, problems with xenotransplants from animals such as primates and pigs often occur at the interface of the human blood supply and the organ, where human blood flows through pig veins.
Dr. Montgomery said that the organ working outside the body is a strong indication that it will work in the body.
“It was even better than we expected,” he said. “It looked like any transplant I had from a living donor. Most kidneys of deceased people do not work immediately and take days or weeks to start. It worked immediately.”
According to the United Network for Organ Sharing, a nonprofit that coordinates the nation’s organ procurement efforts, 39,717 people in the United States received organ transplants last year, most of whom – 23,401 – received kidneys.
Dr. Genetically engineered pigs “could be a potentially sustainable, renewable source of organs—the sun and wind of organ availability,” Montgomery said.
Reactions to the news among transplant experts ranged from cautious optimism to wildly enthusiastic, but all agreed that the procedure represented a sea change. While the possibility of raising pigs to harvest their organs for humans raises questions about animal welfare and exploitation, approximately 100 million pigs are killed for food each year in the United States.
While some surgeons thought it would only take months to transplant the kidneys of genetically engineered pigs into living humans, others said there is still a lot of work to be done.
A former transplant surgeon and chief medical officer of the organ procurement organization LiveOnNY, Dr. “This is truly state-of-the-art translational surgery and transplantation that is on the verge of being able to do it in living humans,” said Amy Friedman. greater New York area.
The group was involved in the selection and identification of the brain-dead patient who received the experimental procedure. The patient was a registered organ donor and, as the organs were not suitable for transplantation, the patient’s family agreed to allow studies to test the experimental transplant procedure.
Dr. Friedman said he also dreams of using hearts, livers and other organs raised in pigs. “It’s really mind-blowing to think about how many transplants we can offer,” he said. “Of course you have to raise the pigs.”
Other experts were more timid, saying they wanted to see if the results were reproducible and review the data collected by NYU Langone.
Deputy director of the transplant center at Massachusetts General Hospital, Dr. “There’s no doubt that it’s a strength, because that’s hard to do and you have to jump through a lot of hoops,” said Jay A. Fishman.
Dr. “Whether this particular study advances the field will depend on what data they collect and whether they share it, or whether it’s just a step forward to show they can do it,” Fishman said. It promoted humility “about what we know.”
United Network for Organ Sharing’s chief medical officer, Dr. David Klassen said that there are many obstacles to the use of genetically modified pig organs in living humans.
While calling the surgery “a turning point”, he warned that prolonged rejection of organs occurs when the donor kidney is well-matched and “even when you’re not trying to break through the species barriers.”
The kidney has functions besides cleansing the blood from toxins. And saying there are concerns about swine viruses infecting buyers, Dr. “This is a complex field and it would be naive to imagine that we know everything that will happen and all the problems that will arise,” Klassen said.
Xenotransplantation, the process of grafting or transplanting organs or tissues between different species, has a long history. Efforts to use the blood and skin of animals in humans date back hundreds of years.
In the 1960s, chimpanzee kidneys were transplanted into a small number of human patients. Most died soon after; The longest a patient lived was nine months. In 1983, a baboon heart was transplanted into a girl known as Baby Faye. He died 20 days later.
Pigs offered advantages over primates for organ retrieval—easier to rear, reach maturity faster, and reach adult human size in six months. Pig heart valves are routinely transplanted into humans, and some patients with diabetes are given pig pancreatic cells. Pigskin has also been used as a temporary graft for burn patients.
The combination of two new technologies – gene editing and cloning – has yielded genetically modified pig organs. Pig hearts and kidneys have been successfully transplanted into monkeys and baboons, but safety concerns have prevented their use in humans.
Dr. “Until now, the field has remained in the preclinical primate stage, because moving from primate to living human is perceived as a big leap,” Montgomery said.
The kidney used in the new procedure was obtained by knocking out a pig gene encoding a sugar molecule that elicits an aggressive human rejection response. Pig has been genetically engineered by Revivicor and approved by the Food and Drug Administration for use as a source for human therapeutics.
Dr. Montgomery and his team also transplanted pig’s thymus, a gland involved in the immune system, to prevent immune reactions to the kidney.
After connecting the kidney to blood vessels in the upper leg, surgeons covered it with a protective shield so they could observe and take tissue samples during the 54-hour study period. Dr. Urine and creatinine levels were normal, Montgomery and colleagues found, and no signs of rejection were detected during more than two days of observation.
Dr. “There didn’t seem to be any incompatibility between pig kidney and human that wouldn’t make it work,” Montgomery said. “There was no immediate rejection of the kidney.”
The official acknowledged that long-term prospects are still unknown. But “this allowed us to answer a really important question: Is there something catastrophic that will happen when we move this from a primate to a human?”
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