The first person whose failing heart was replaced by that of a genetically modified pig died on Tuesday May 9, two months after his heart transplant.
David Bennett, 57, a handyman with heart failure, underwent a highly experimental procedure at the University of Maryland Medical Center in January, in which doctors transplanted him with a genetically modified pig’s heart.
Bennett died in March, just months after the procedure. The hospital just said his condition deteriorated within days but did not provide a cause of death.
Bennett’s transplant surgeon, Bartley Griffith, revealed last month that the pig’s heart had been infected with porcine cytomegalovirus, which may have contributed to his death. Griffith presented the virus and doctors’ attempts to treat it during a webinar hosted by the American Society of Transplantation on April 20, according to MIT Technology Review.
“We’re starting to understand why he died,” Griffith said, adding, “[the virus] could have been the actor, or could have been the actor, who started it all.
The resilience of the human immune system is the main obstacle to animal-to-human organ transplants, as it can target foreign cells in a process called rejection, triggering a response that will eventually destroy the transplanted organ or tissue.
Experts said the operation was an “important test of xenotransplantation”, which involves transplanting tissue from different species. Because the pigs used to deliver organs are supposed to be virus-free, they believe the experiment was stopped by “unforced error”.
“If there was an infection, we can most likely prevent it in the future,” Griffith said during the webinar.
The ability of the human immune system to target foreign cells in a process known as rejection, triggering a response that will ultimately destroy the transplanted organ or tissue, is the fundamental barrier in animal organ transplants to human.