First-ever pig-to-human heart transplant offers hope for thousands in need of organs

"At that point, the race was on."Others in the field were supportive, if a bit envious."We've all been doing this for a really long time, and I'm sure it's got to be fun to be first," said Joseph Tector, a transplant surgeon and xenotransplantation researcher at the University of Miami.Tector, who focuses on kidney transplants, said he's waiting until he's confident he can provide reliable, durable results, "so that when we do it, we can help everybody."Animal rights activists object to the use of pig organs. “I believe there's continued reason to be hopeful.”Even if it doesn't change his outcome, the surgery allows Bennett to leave a legacy, David said."Regardless of what happens, I want to help other people," Bennett told his son before the surgery.Bennett had a pig valve implanted almost a decade ago, and bacon is his favorite food, so the idea of receiving a part from a pig didn't bother him much, David said, although he still hopes he'll be able to get a human heart. One final gene was turned off to keep the pig from growing too large.The 1-year-old pig that gave its heart to Bennett weighed about 240 pounds; a standard male pig of the same age might weigh 450 pounds, said David Ayares, Revivicor's executive vice president and chief scientific officer.Researchers learned from studies in baboons that without editing out this growth gene, even an organ taken from a young animal would keep growing. In a couple of the baboons, the transplanted pig hearts grew too big for their chests."We've marched down this road over the last decade, going from a one-gene pig to a two- to a five- to an eight to a 10, and we rationalized each of those and made modifications along the way," Ayares said.Ayares has worked for two decades to develop pigs that are suitable for human transplant. Revivicor's parent company, United Therapeutics, aims to get into pig-to-human lung transplants, whose pigs will probably need "at least that many" gene edits, Ayares said.A second innovative aspect of the surgery is the use of an immunosuppressive medication that seems to be essential for long-term survival of a transplanted organ. "Nobody understands why."Bruno Reichart, a retired German heart transplant surgeon, who tested pig hearts in baboons for years, said he thinks the pig heart probably works better if liquid continually flows through it. That's part of the experience they'll gain now."Reichart, CEO of a company he co-founded to commercialize pig-to-human heart transplants, called XTransplant, said he's concerned that Bennett was turned down for a transplant because he didn't take previous prescriptions."The patient has a great responsibility to other patients in the world to behave properly and take his medications," Reichart said.