Researchers successfully transplant genetically modified pig hearts into two recently deceased people connected to the ventilator, the New York University team announced today. The surgery is the latest step in the field of animal-to-human transplantation, or xenotransplantation, which has seen a flurry of successes so far this year – raising hopes for a new, steady supply of organs to ease shortages.
The only thing different about these heart transplants was that of a typical human-to-human heart transplant, the research team said in a statement. Nadar Moazmi, director of heart transplantation at the NYU Langone Transplant Institute, said, “Our goal is to integrate the practices used in a common, everyday heart transplant, with only a nonhuman organ that can be used without tested equipment or drugs. will function normally without additional support.” ,
The team performed transplants on June 16 and July 9, and each recipient was monitored for three days. At that time, the hearts functioned normally, and there were no signs of rejection from recipients who, even after death, were connected to ventilators to keep their body’s processes functioning semi-regularly. Two recipients were not able to become organ donors, but were able to participate in whole body donation for this type of research.
The two pig hearts came from the biotechnology company Revvicor, which produces (and also funds the research) genetically modified pigs. The pigs had 10 genetic modifications – four to block pig genes and prevent rejection and six to add human genes.
A live person was successfully given a pig heart in early January at the University of Maryland Medical Center, also manufactured by Revivcor. David Bennett Sr., who had severe heart disease, initially responded well to the transplant, but died of heart failure in March. The specific cause is still unknown, but virus infection in the pig may have contributed to his death. Pig hearts are known to be free of the virus, but experts say they can be difficult to detect.
The NYU team said it introduced additional virus screening protocols for its transplant. It also dedicated an operating room for xenotransplantation – that room would not be used for any other surgical procedures.
Robert Montgomery, director of the NYU Langone Transplant Institute, said during a press briefing that testing transplants on deceased patients is still important, even if a pig’s heart has already been transplanted into a living one. “Meditation is really trying to learn, study, measure, and really know what’s going on with this brand new, incredible technology,” he said. For example, the team was able to take biopsies every day. The research team at the University of Maryland was not able to study the transplant in more detail because the recipient was still alive, he said.
Brain-dead patients have also been used to test kidney xenotransplantation at NYU. This fall, NYU announced that it had successfully attached a pig kidney to the leg of a patient on a ventilator. The patient’s body did not reject the organ, and it functioned normally through 54 hours of observation.
Research teams are still working towards full clinical trials of xenotransplantation in living people. To do so they would need permission from the Food and Drug Administration. Montgomery said at the press briefing that the NYU team aims to expand the amount of time they spend monitoring a transplanted heart so that more information can be gathered to inform trials. He believes that clinical trials can start between now and 2025. Rivicor said in April that it expected to begin clinical trials in the next year or two.
There is still much to learn about xenotransplantation and much to explore about the ethical implications of animal-to-human procedures. But if they work, they could give thousands of people a new option on organ waiting lists.
“I believe xenotransplantation offers the best chance for a renewable, sustainable source of organs so that someone doesn’t have to die waiting for an organ,” Montgomery said.