from the ripped-out dept.
The first person to receive a heart transplant from a pig has died, two months after the groundbreaking experiment, the Maryland hospital that performed the surgery announced Wednesday.
David Bennett, 57, died Tuesday at the University of Maryland Medical Center. Doctors didn't give an exact cause of death, saying only that his condition had begun deteriorating several days earlier.
[...] Prior attempts at such transplants — or xenotransplantation — have failed largely because patients' bodies rapidly rejected the animal organ. This time, the Maryland surgeons used a heart from a gene-edited pig: Scientists had modified the animal to remove pig genes that trigger the hyper-fast rejection and add human genes to help the body accept the organ.
At first the pig heart was functioning, and the Maryland hospital issued periodic updates that Bennett seemed to be slowly recovering. Last month, the hospital released video of him watching the Super Bowl from his hospital bed while working with his physical therapist.
Bennett survived significantly longer with the gene-edited pig heart than one of the last milestones in xenotransplantation — when Baby Fae, a dying California infant, lived 21 days with a baboon's heart in 1984.
[...] One next question is whether scientists have learned enough from Bennett's experience and some other recent experiments with gene-edited pig organs to persuade the FDA to allow a clinical trial — possibly with an organ such as a kidney that isn't immediately fatal if it fails.
Donated human organs are in such short supply that thousands of people die waiting for one every year. U.S. researchers have been shattering records in xenotransplantation, or between-species organ transplants.
The researchers say they have kept a pig heart alive in a baboon for 945 days and also reported the longest-ever kidney swap between these species, lasting 136 days. The experiments used organs from pigs "humanized" with the addition of as many as five human genes, a strategy designed to stop organ rejection.
The GM pigs are being produced in Blacksburg, Virginia, by Revivicor, a division of the biotechnology company United Therapeutics. That company's founder and co-CEO, Martine Rothblatt, is a noted futurist who four years ago began spending millions to supply researchers with pig organs and has quickly become the largest commercial backer of xenotransplantation research.
Rothblatt says her goal is to create "an unlimited supply of transplantable organs" and to carry out the first successful pig-to-human lung transplant within a few years. One of her daughters has a usually fatal lung condition called pulmonary arterial hypertension. In addition to GM pigs, her company is carrying out research on tissue-engineered lungs and cryopreservation of organs. "We're turning xenotransplantation from what looked like a kind of Apollo-level problem into just an engineering task," she says.
Man Gets Genetically-Modified Pig Heart in World-First Transplant
A US man has become the first person in the world to get a heart transplant from a genetically-modified pig. David Bennett, 57, is doing well three days after the experimental seven-hour procedure in Baltimore, doctors say.
The transplant was considered the last hope of saving Mr Bennett's life, though it is not yet clear what his long-term chances of survival are.
"It was either die or do this transplant," Mr Bennett explained a day before the surgery.
"I know it's a shot in the dark, but it's my last choice," he said.
Doctors at the University of Maryland Medical Center were granted a special dispensation by the US medical regulator to carry out the procedure, on the basis that Mr Bennett would otherwise have died.
[...] He had been deemed ineligible for a human transplant, a decision that is often taken by doctors when the patient is in very poor health.
Earlier this year, news broke of the first experimental xenotransplantation: A human patient with heart disease received a heart from a pig that had been genetically engineered to avoid rejection. While initially successful, the experiment ended two months later when the transplant failed, leading to the death of the patient. At the time, the team didn't disclose any details regarding what went wrong. But this week saw the publication of a research paper that goes through everything that happened to prepare for the transplant and the weeks following.
Critically, this includes the eventual failure of the transplant, which was triggered by the death of many of the muscle cells in the transplanted heart. But the reason for that death isn't clear, and the typical signs of rejection by the immune system weren't present. So, we're going to have to wait a while to understand what went wrong.
[...] The presence of an apparent pig cytomegalovirus was worrying, but the researchers indicate there's some question about whether the tests that picked it up might have been recognizing a closely related human virus—one that's often associated with organ transplant problems.
So, for now, it's not clear what happened with this transplant or what the significance of the apparent viral infection is. Obviously, the team has lots of material to work with to try to figure out what went on, and there's a long, long list of potential experiments to do with it. And there are also additional xenotransplant trials in the works, so it may not be long before we have a better sense of whether this was something specific to this transplant or a general risk of xenotransplantation.