For the first time, US medical professionals have transplanted a pig’s heart into a human. Incurable heart disease patient David Bennett received a genetically modified pig heart in an eight-hour operation on Friday, January 7th at the University of Maryland Medical Center. The operation was a last-ditch effort to save 57-year-old Bennett, who was out of the question for a conventional heart transplant, the center announced. Before the procedure, he had been in the hospital for more than six weeks with life-threatening arrhythmias. “It was either die or do this transplant,” he said in the press release. “I want to live. I know it’s a shot in the dark, but it’s my last choice.”
Before the transplant, ten genes were changed in the donor pig. Three of these genes are responsible for the rejection of pig organs in humans, so these genes have been “switched off”. Six genes were inserted to control the immune acceptance of the pig heart and another gene was switched off to prevent overgrowth of the pig heart tissue.
“Green light” for the daring transplant
The team in Maryland also used a new drug from Kiniksa Pharmaceuticals, which has not yet been extensively tested, to suppress the immune system and prevent rejection reactions. A new machine was also used to force fluid through the tissue to ensure the pig’s heart remained viable until the procedure. As reported by the New York Times, the FDA gave the go-ahead for the procedure on New Year’s Eve.
University of Maryland
“It is a huge step forward in transplant medicine, comparable to the first allotransplantation (Transplantation between genetically different individuals of the same species; editor’s note) by Christian Barnard 1967 “, is how Dr. Joachim Denner, head of the working group for virus safety in xenotransplantation at the Institute of Virology at the Free University of Berlin, assesses the procedure and refers to the numerous patients who are on waiting lists for a donor organ.
When removing the pig heart from the pig.
(Bild: University of Maryland)
According to the Health Resources and Services Administration, a federal agency, there are nearly 107,000 people on the transplant waiting list in the United States, 17 of whom die every day. In Germany, according to the Eurotransplant Foundation 9,192 patients (As of January 1, 2021) on the waiting list for a donor organ. 2,880 organ transplants from deceased donors took place in 2020, 587 of them were donor hearts.
The biologist Anne Meinert, specialist in the field of animal experiments at PETA, appeals to politicians to work towards increasing the willingness to donate organs. Criticizing the procedure, she commented: “Animal-to-human transplants are ethically unjustifiable and dangerous. It also wastes important resources that could instead be invested in research that actually helps humans.”
“If there are ethical concerns about these experiments, it should be clearly stated that the goal of xenotransplantation is to extend the life of people. In all world religions this is clearly above the life of an animal, which is why xenotransplantation is consistently supported here,” explains Dr. Konrad Fischer, head of the Xenotransplantation Section at the Technical University of Munich.
Surgeon Bartley P. Griffith (left) and patient David Bennett.
(Bild: University of Maryland)
Meanwhile, things look promising for Bennett. He’s fine. A hyperacute rejection reaction, which can occur after a few hours with such transplants, did not occur. Therefore today (January 11th) he is to be separated from the cardiopulmonary bypass machine that kept him alive.
Gene editing offers new opportunities for xenotransplantation
With this method, the path of so-called xenotransplantation, i.e. the transplantation of animal organs or tissues into humans, is taken further. After many unsuccessful uses, new gene editing technologies seem to make the process more and more practical. The genetically modified pig in the operation was supplied by Revivicor, one of several biotech companies working to develop pig organs for transplantation into humans.
Revivicor was also behind the successful transplant of a pig kidney into a human patient last October. That, too, was an important milestone in demonstrating the viability of the firm’s techniques. In addition to Revivicor, Harvard scientist George Church is co-founder of the company eGenesis, which is working on using CRISPR genetic engineering to make animal organs usable for transplantation in humans.
(jle)
