Washington: US surgeons have successfully transplanted a heart from a genetically modified pig into a 57-year-old man, a therapy first that could one day help solve a chronic shortage of organ donation.
The “historic” process took place on Friday, the University of Maryland Medical School said in a statement on Monday. While the patient prognosis is far from certain, it represents a major milestone for animal-to-human transplantation.
The patient, David Bennett, was deemed ineligible for a human transplant – a decision often made when the recipient’s underlying health is very poor.
He is now recovering and is being carefully monitored to determine how the new organ is performing.
“Either died or it transplanted. I want to live. I know it’s a shot in the dark, but it’s my last choice,” the Maryland resident said the day before surgery.
Bennett, who had been bedridden on a heart-lung bypass machine for the past several months, said: “I look forward to getting out of bed after I recover.”
The Food and Drug Administration granted emergency authorization for the surgery on New Year’s Eve, as a last-ditch effort for a patient unfit for a traditional transplant.
“It was a successful surgery and brings us one step closer to solving the organ shortage crisis,” said Bartley Griffith, who had surgically transplanted pig hearts.
“We are proceeding with caution, but we are also optimistic that this first surgery in the world will provide an important new option for patients in the future.”
Muhammad Mohiuddin, who co-founded the university’s cardiac xenotransplantation program, said the surgery was the culmination of years or years of research, including pig-to-baboon transplants, with survival times exceeding nine months.
“The successful procedure provided valuable information to help the medical community improve this potentially life-saving method in future patients,” he said.
Bennett’s donor pig was from a herd that had undergone genetic editing procedures.
Three genes that led to the rejection of pig organs by humans were “knocked out”, as was a gene that would have caused excessive growth of pig heart tissue.
The six human genes responsible for human acceptance were inserted into the genome for a total of 10 unique gene editing.
The editing was done by Virginia-based biotech firm Revvicor, which in October supplied the pig used in a successful kidney transplant on brain dead patients in New York City.
But while that surgery was purely a proof-of-concept experiment, and the kidney was attached outside the patient’s body, the new surgery aims to save a person’s life.
The donated organ was placed in an organ-preservation machine prior to surgery, and the team used traditional anti-rejection drugs as well as an experimental new drug made by Kinikasa Pharmaceuticals to suppress the immune system.
According to official figures, approximately 110,000 Americans are currently awaiting organ transplants, and more than 6,000 patients die each year.
To meet demand, doctors have long been interested in so-called xenotransplantation, or cross-species organ donation, with experiments going back to the 17th century.
Early research focused on harvesting organs from primates — for example, a baboon heart was transplanted into a newborn known as “Baby Fae” in 1984, but she survived only 20 days.
Today, pig heart valves are widely used in humans, and pigskin is applied to human burn victims.