In January last year, a 57-year-old heart disease patient in the United States received a genetically modified pig heart transplant, which was also the world's first pig heart transplant.After the initial surgery, the patient reported feeling very well, but died two months later as his condition worsened. It is reported that the pig heart that was transplanted into his body contained porcine cytomegalovirus, a very common virus that is usually controlled by the immune system.
Following a global precedent, the University of Maryland Medical Center in the United States recently completed the second operation of transplanting a genetically modified pig heart to a patient.
The patient is still in the observation period and is recovering well. He can sit up in a chair and even joke two days after the operation.
Like the first time, the pig hearts used by the surgical team this time were provided by Revivecor, a subsidiary of United Therapeutics, and also involved 10 specific gene edits.
Among them, three genes were "knocked out" or inactivated to reduce the risk of triggering a severe reaction from the human immune system; one gene was modified to prevent excessive proliferation of pig heart tissue; and six human genes were added to improve the acceptance of the human immune system and promote the body's acceptance of xenogeneic organs.
Researchers learned some experience from the first genetically modified pig heart xenotransplantation operation in January last year, and found better detection methods before the operation to closely screen the donor pig heart for symptoms of infection with viruses and other pathogens.