Posted on 05/09/2022 at 7:37 p.m.,
Reading 2 mins.
In March, the first man to be transplanted with a pig’s heart died. The reason for his death was unknown until then. But, at the beginning of May, the researchers discovered that the graft was carrying a porcine virus, which could have prevented the proper functioning of the heart.
Remember, on January 7, a man had a pig’s heart transplant in the United States. David Bennett Sr was 57 years old, he had terminal heart disease and had been deemed ineligible for human transplantation. It was his last hope.
To avoid rejection of the pig’s heart by the immune system, it had been genetically modified. But two months after this revolutionary transplant, the American died. At the time, researchers announced that no obvious cause of his death had been identified. They have since investigated.
A porcine cytomegalovirus
In March, the surgeon who performed the transplant, Dr Bartley Griffith, said his patient woke up one morning with symptoms similar to an infection, although he seemed to be accepting the transplant. The pig’s heart thus began to swell, filled with liquid and eventually ceased to function.
But after several months of research, doctors at the University of Maryland discovered a nasty surprise inside the transplanted pig’s heart: viral DNA. The heart was infected with a microbe called porcine cytomegalovirus. However, researchers cannot yet fully confirm the role of the virus in the patient’s death.
“The reaction does not appear to be typical organ rejection”explained Dr. Griffith, adding that the investigation was still ongoing.
“We are beginning to understand why he died”he added, thinking that the virus “maybe the actor, or could be the actor, who started this whole thing”.
A worrying discovery for xenografts
For years, doctors have been trying to transplant animal organs into human beings, to no avail. This is called a xenograft (or xenotransplantation).
According to the Maryland team that performed the transplant, the donor pig was in good health and had passed all the tests required by the Food and Drug Administration to check for infections. This xenograft therefore brought together all the elements to prosper.
But the discovery of porcine cytomegalovirus worries specialists about future organ transplants from animals to humans. Indeed, doctors warn of the potential risk of introducing new types of animal infections in humans.
According to Dr. Griffith, some viruses are “latent”, that is to say, they hide in their body without causing disease. This is one of the reasons why researchers continue their medical experiments, “so as not to miss any virus”.