Over the years, scientists have gone from primates to pigs, tinkering with their genes.
In a medical first, doctors transplanted a pig heart into a patient in a final attempt to save his life, and a Maryland hospital said Monday he was doing well three days after the highly experimental surgery.
While it is too early to know whether the operation will actually work, it is a step in the decades-long quest to one day use animal organs for life-saving transplants. Doctors at the University of Maryland Medical Center say the transplant has shown that the heart of a genetically modified animal can function in the human body without immediate rejection.
The patient, David Bennett, a 57-year-old Maryland handyman, knew that there was no guarantee the experiment would work, but that he was dying, unfit for human heart transplant and had no other choice, his son. told The Associated Press.
“It was either die or transplant it. I want to live I know it’s a shot in the dark, but it’s my last choice,” Mr Bennett said the day before the surgery, according to a statement provided by the University of Maryland School of Medicine.
On Monday, Mr Bennett was breathing on his own while being connected to a heart-lung machine to help his new heart. The next few weeks will be crucial as Mr. Bennett recovers from surgery and doctors carefully monitor how his heart is doing.
There is an acute shortage of donated human organs for transplantation, forcing scientists to figure out how to use animal organs instead. Last year, just over 3,800 heart transplants took place in the US, a record number, according to the United Network for Organ Sharing, which oversees the country’s transplant system.
“If it works, there will be an endless supply of these organs for afflicted patients,” said Dr. Muhammad Mohiuddin, scientific director of the University of Maryland’s animal-to-human transplant program.
But prior attempts at such transplantation – or xenotransplantation – have failed, mainly because the patients’ bodies rapidly rejected the animal organ. Notably, in 1984, Baby Fay, a dying infant, lived 21 days with a baboon heart.
The difference this time: Surgeons in Maryland used the heart of a pig that had been gene-edited to remove a sugar in its cells that is responsible for that hyper-fast organ rejection. Several biotech companies are developing pig organs for human transplantation; The one used for Friday’s operation came from Revvicor, a subsidiary of United Therapeutics.
“I think you can characterize this as a watershed event,” UNOS chief medical officer Dr. David Klaasen said of the Maryland transplant.
Still, Dr. Klaasen cautioned that this is only a tentative first step toward finding out whether, this time around, xenotransplantation might eventually work.
The Food and Drug Administration, which oversees such experiments, allowed the surgery under “compassionate use” emergency authorization when a patient with a life-threatening condition has no other option.
It will be important to share the data collected from this transplant before reaching more patients, said Karen Mashke, a research scholar at the Hastings Center, which will provide ethics and policy recommendations for the first clinical trials under a national grant. helping to develop. Health Institute.
“Without this information it would not be appropriate to rush into animal-to-human transplantation,” Ms Maschke said.
Over the years, scientists have gone from primates to pigs, tinkering with their genes.
Last September, researchers in New York conducted an experiment that suggested this type of pig could hold promise for animal-to-human transplants. Doctors temporarily attached a pig kidney to a dead human body and watched it begin to function.
The Maryland transplant takes their experiment to the next level, said Dr. Robert Montgomery, who led that work at NYU Langone Health.
“This is truly a remarkable success,” he said in a statement. “As a heart transplant recipient myself suffering from a genetic heart disorder, I am thrilled by this news and the hope it gives to my family and other patients who ultimately saved from this success.”
The surgery, which took place last Friday at a Baltimore hospital, took seven hours. Dr. Bartley Griffith, who performed the surgery, said the patient’s condition – heart failure and irregular heartbeat – made him ineligible for a human heart transplant or heart pump.
Dr. Griffith transplanted pig hearts into about 50 baboons over five years, before giving Bennett the option.
“We are learning a lot every day with this gentleman,” said Dr. Griffith. “And so far, we’re happy with his decision to move on. And so is he: He has a big smile on his face today.”
Pig heart valves have also been used successfully in humans for decades, and Mr. Bennett’s son said his father received one about a decade ago.
As for the heart transplant, “he feels the magnitude of what was done and he really feels the importance of it,” said David Bennett Jr. “He couldn’t survive, or he could last a day, or he could last a few days. I mean, we’re in the unknown at the moment.”
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