(ORDO NEWS) — Two genetically modified porcine hearts have been successfully transplanted into humans, marking the second significant advance in porcine and human heart xenotransplantation this year.
“It was one of the most incredible things to see a pig’s heart pounding and beating in a person’s chest,” Dr. Robert Montgomery, director of the NYU Langone Transplant Institute, where the transplant took place, said at a press conference on Tuesday.
One of the transplants took place in mid-June, and the second was completed on July 6th.
But there is one catch. The two patients who received pig organs were brain-dead people whose hearts kept beating on ventilators to receive pig organs. It will likely be years before a pig-to-human transplant becomes a routine and reliable alternative for people on long waiting lists for hearts, kidneys and other vital organs.
“It will be an iterative process of learning, changing tactics,” says Montgomery, who is himself a heart transplant recipient.
However, the doctor hopes pig organs could one day be “a renewable, sustainable source of organs so no one has to die waiting.”
Human trials could become a reality in the next few years
In January, the University of Maryland performed the first known operation to transplant a human-pig heart into a living patient. The transplant was performed on a 57-year-old man with a life-threatening heart condition.
“Either die or get this transplant,” the patient, David Bennett Sr., said the day before the operation. “I know it’s a shot in the dark, but this is my last choice.”
Bennett’s new pig heart failed after two months. Pig virus DNA was later found in the heart, but there were no signs of active infection, the surgeon who performed the operation told The New York Times.
“We don’t know why the heart failed and why he died,” Montgomery said. That is why, in his opinion, it is important to continue research on deceased donors before proceeding to trials of living heart xenotransplantation.
“This is a huge, huge step in the right direction,” Dr. Chris Colbert, an ER doctor in Chicago who was not involved in the study, told Insider when he learned the news. “This is not just an organ, but a coincidence of organs.”
Two pig hearts transplanted this summer at New York University were able to function for at least 72 hours in a human body because 10 genetic changes were made to them.
Four of these genes were porcine to prevent transplant rejection and abnormal growth, and six were human transgenes designed to make human and porcine parts more compatible.
“This is really the next frontier in transplantation,” Dr. Preity Pirlamarla, a heart transplant cardiologist at New York’s Mount Sinai Hospital who was not involved in the NYU study, told Insider. “It’s really just a modern miracle that we even think about it.”
Routine pig-to-human heart transplant could become ‘very possible’ within a decade
Before a pig-to-human heart transplant becomes routine, Prilamarla says, doctors will need to better understand how to make the modified pig organs more compatible with living, moving human bodies so they won’t be rejected by recipients.
Researchers and surgeons will also need to make sure “we don’t transmit some unforeseen infection that will be in a pig and then transmitted to humans,” she added.
But she also said she wouldn’t be surprised if pig-to-human heart transplants become commonplace over the course of her career.
“Will I see it happen in the coming year? I don’t think so,” she said. “Do I see it happening in 5, 10 years? I think it’s very possible.”
Heart disease is the number one killer in the US and demand for heart transplants is high.
In addition to genetically modified pig hearts, there are other ways to reduce the waiting time for vital organs.
Already, bipartisan members of Congress are calling for a “long overdue” reorganization of the “underperforming” and even “non-performing” federal organ-purchasing organizations that are responsible for distributing organs nationwide.
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