In a medical first, doctors transplanted a pig’s heart into a patient in a last-ditch effort to save his life and a hospital in Maryland said on Monday he was fine three days after the highly experimental surgery.
Although it’s too soon to know if the surgery will really work, it marks a milestone 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 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, ineligible for a human heart transplant and had no other option, her son told The Associated Press.
“It was either die or do this transplant. I want to live. I know it’s a shot in the dark, but it’s my last choice,” Bennett said a day before the surgery, according to a release provided by the University of Maryland School of Medicine.
On Monday, Bennett was breathing on his own while staying connected to a heart-lung machine to help his new heart. The next few weeks will be crucial as Bennett recovers from surgery and doctors carefully monitor the condition of his heart.
There is a huge shortage of human organs donated 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 United States, 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 patients who are suffering,” said Dr. Muhammad Mohiuddin, scientific director of the animal-to-human transplant 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. Notably, in 1984, Baby Fae, a dying infant, lived 21 days with the heart of a baboon.
The difference this time: Maryland surgeons used the heart of a pig that had undergone genetic modification to eliminate a sugar in its cells that is responsible for this hyper-rapid organ rejection. Several biotechnology companies are developing pig organs for human transplantation; the one used for Friday’s operation was from Revivicor, a subsidiary of United Therapeutics.
“I think you can characterize it as a watershed event,” UNOS chief medical officer Dr. David Klassen said of the Maryland transplant.
Still, Klassen warned that this was only a tentative first step in determining whether this time around xenotransplantation might finally work.
The Food and Drug Administration, which oversees such experiments, has cleared the surgery under what’s called emergency “compassionate use” clearance, available when a patient with a life-threatening condition hasn’t no other options.
It will be crucial to share the data collected from this transplant before expanding it to more patients, said Karen Maschke, a researcher at the Hastings Center, who helps develop ethical and policy recommendations for early clinical trials in the framework. a grant from the National Institutes of Health.
“Rushing into animal-to-human transplants without this information would be undesirable,” Maschke said.
Over the years, scientists have moved from primates to pigs, tinkering with their genes.
Last September, researchers in New York performed an experiment suggesting that these types of pigs might hold promise for animal-to-human transplants. Doctors temporarily attached a pig kidney to a deceased human body and watched it begin to function.
Maryland Transplant takes their experience to the next level, said Dr. Robert Montgomery, who led this work at NYU Langone Health.
“This is a truly remarkable breakthrough,” he said in a statement. “As a heart transplant recipient, myself with a genetic heart condition, I am thrilled by this news and the hope it gives my family and other patients who will eventually be saved by this breakthrough.”
Last Friday’s operation lasted seven hours at the Baltimore hospital. Dr Bartley Griffith, who performed the operation, said the patient’s condition – heart failure and an irregular heartbeat – made him ineligible for a human heart transplant or heart pump.
Griffith had transplanted pig hearts into about 50 baboons over five years, before offering Bennett the option.
“We learn a lot every day with this gentleman,” Griffith said. “And so far we are happy with our decision to move forward. And he is too: 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 received one about a decade ago.
As for the heart transplant, “He realizes the magnitude of what’s been done and he really realizes the importance of it,” David Bennett Jr. said. “He couldn’t live, or he could last a day, or it could last a few days. I mean, we’re into the unknown at this point.
AP Medical Writer Lauran Neergaard contributed.
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