Last year, the world's first xenotransplantation was carried out - the transplantation of an animal organ to a person: a pig kidney was transplanted to a patient who needed a kidney. And in January of this year, a pig heart was transplanted to a man for the first time. The patient, named David Bennett, lived with the new organ for two months before dying of unknown causes. This time, surgeons from New York University Langone transplanted pig hearts to already dead people - to study tissue and blood samples and better understand the effect of transplantation on the human body, reports NewScientist.
Operations took place on June 16 and July 6 involving dead people on life support systems whose relatives donated bodies to science. One of them was a 73-year-old man who had undergone two open-heart surgeries, the identity of the second was not released. Both were observed for three days, all the time there were no signs of rejection, the hearts functioned properly, maintaining blood flow throughout the body.
Xenotransplantation would help solve the problem of shortage of donor organs, due to which many potential recipients die without waiting for the operation. However, transplanting animal organs to humans is associated with another problem - transplant rejection, when the immune system attacks the transplanted organ, and it eventually fails.
To avoid this, the participants in the latest experiment used pig hearts with 10 genetic modifications. Four porcine genes that increase the risk of transplant rejection and abnormal organ growth were switched off, and six human genes were introduced to help reduce incompatibility between biological pathways in pigs and humans. In addition, doctors have tried to solve the problem of virus infection, which is often encountered in xenotransplantation. Pigs that are bred for organ transplants live in special conditions that protect them from pathogens. However, in the blood of the first patient to whom a porcine heart was transplanted, despite all the precautions, porcine cytomegalovirus was found after transplantation, which infected the transplanted organ. During the current experiment, doctors used ultrasensitive screening, and viruses were not detected in any of the two pig hearts.
In the next few years, the first phase of clinical trials of heart xenotransplantation should take place.