In a medical first, doctors transplanted a pig heart into a patient in a last-ditch effort to save his life, and a Maryland hospital said Monday that he is fine three days after the highly experimental surgery.
While it is too early to know if the operation will actually work, it marks 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 demonstrated that a heart from a genetically modified animal can function in the human body without immediate rejection.
The patient, David Bennett, a 57-year-old handyman from Maryland, knew there was no guarantee the experiment would work, but he was dying, was ineligible for a human heart transplant and had no other choice, his son told The Associated Press.
“It was either dying or doing this transplant. I want to live. I know it’s a shot in the dark, but it’s my last option, ”Bennett said the day before surgery, according to a statement provided by the University of Maryland School of Medicine.
On Monday, Bennett was breathing on his own while still hooked up to a heart-lung machine to support his new heart. The next few weeks will be critical as Bennett recovers from surgery and doctors carefully monitor how his heart is doing.
There is a severe shortage of donated human organs for transplantation, leading scientists to try to figure out how to use animal organs instead. Last year, there were just over 3,800 heart transplants in the US, a record number, according to the United Network for Organ Sharing, which oversees the country’s transplant system.
“If this works, there will be an endless supply of these organs for suffering patients,” said Dr. Muhammad Mohiuddin, scientific director of the Animal-to-Human Transplantation Program at the University of Maryland.
But previous attempts at such transplants, or xenotransplants, have failed, largely because the patients’ bodies quickly rejected the animal organ. In particular, in 1984, Baby Fae, a dying baby, lived for 21 days with a baboon heart.
The difference this time: Maryland surgeons used a heart from a pig that had undergone gene editing to remove a sugar in its cells that is responsible for that hyper-rapid organ rejection. Several biotech companies are developing pig organs for human transplantation; the one used for Friday’s operation came from Revivicor, a subsidiary of United Therapeutics.
“I think it can be characterized as a milestone,” said Dr. David Klassen, UNOS medical director, of the Maryland transplant.
Still, Klassen cautioned that it’s just a tentative first step in exploring whether this time, xenotransplantation could finally work.
The Food and Drug Administration, which oversees such experiments, allowed the surgery under what is called an emergency “compassionate use” authorization, available when a patient with a life-threatening condition has no other options.
It will be crucial to share the data collected from this transplant before rolling it out to more patients, said Karen Maschke, a research fellow at the Hastings Center, who is helping to develop ethical and policy recommendations for the first clinical trials with a grant from the National Institutes of Medicine. Health.
“It would not be wise to rush into animal-to-human transplants without this information,” Maschke said.
Over the years, scientists have gone from primates to pigs, playing with their genes.
Just last September, researchers in New York conducted an experiment that suggested these types of pigs could hold promise for transplants from animals to humans. Doctors temporarily attached a pig kidney to a deceased human body and watched it begin to function.
The Maryland transplant takes his experiment to the next level, said Dr. Robert Montgomery, who led that work at NYU Langone Health.
“This is a really remarkable development,” he said in a first interview.
“As a heart transplant recipient, myself with a genetic heart disorder, I am excited by this news and the hope it gives to my family and other patients who will eventually be saved by this advancement.”
Last Friday’s surgery lasted seven hours at the Baltimore hospital. Dr. Bartley Griffith, who performed the surgery, said the patient’s condition – heart failure and an irregular heartbeat – made him ineligible for a human heart transplant or a heart pump.
Griffith had transplanted pig hearts into about 50 baboons for five years, before offering the option to Bennett.
“We are learning a lot every day from this gentleman,” Griffith said. “And so far, we are happy with our decision to move forward. And he is too: a big smile on his face today. “
Pig heart valves have also been used successfully for decades in humans, and Bennett’s son said his father had received one a decade ago.
Regarding the heart transplant, “He realizes the magnitude of what was done and he really realizes how important it is,” said David Bennett Jr. “It could not live, or it could last a day, or it could last a couple of days. I mean, we are in the unknown at this point. “