text | Bunlele
html On July 12, American researchers announced that they had successfully transplanted the hearts of genetically modified pigs into two patients who were relying on life support equipment for the first time.
The two men were declared brain dead before the transplant surgery and were on ventilators and undergoing dialysis before, during and after the surgery.
Until last year, xenotransplantation, the transplantation of animal organs into humans, had only been tested on non-human primates.
In September 2021, the first xenotransplantation was performed on a person relying on life support equipment, using a pig kidney.
html July 6, a genetically modified pig heart is suspended in solution before xenograft transplantation. Image source: JOE CARROTTA
In January this year, David Bennett became the first living person to receive a pig heart transplant, but he died two months later for unknown reasons.
"Keeping Bennett alive for two months was an amazing feat, but in the end we didn't know why his heart failed and why he died, which is the limitation of a one-time transplant in a living person."
News held on the day At the press conference, Robert Montgomery of NYU Langone Health said, "This also highlights the benefits of transplanting in deceased people. We can look at tissue and blood samples and conduct a deeper analysis of what happened. ”
The two surgeries were performed on June 16 and July 6 respectively at NYU Langone Tisch Hospital.
The first person to receive a transplant was 73-year-old Larry Kelly, who had previously undergone two heart surgeries.
Information on the second transplant recipient has not yet been released.
The families of both men have donated their bodies for scientific research.
Nader Moazami of NYU Langone Health revealed at a news conference that the transplant followed standard clinical procedures.
After surgery, the researchers observed the two recipients for 72 hours and performed daily biopsies. The results showed that there were no signs of rejection and the heart function was normal - contracting and maintaining blood flow throughout the body.
Xenotransplantation offers a promising solution to the donor organ shortage.
In the United States alone, more than 105,000 people are waiting for an organ transplant, and 17 of them die every day.
However, the main problem with using animal organs is transplant rejection , where the immune system attacks the organ, eventually leading to organ failure.
To avoid this, Moazami and colleagues used 10 genetically modified pig hearts.
4 genes that increase the risk of transplant rejection and abnormal organ growth were turned off, while six additional human genes were inserted to reduce incompatibility between pig and human biological pathways.
The researchers also gave the patients standard post-transplant drugs to suppress the immune response.
Animal viral infection is another possible risk of xenotransplantation.
Therefore, pigs used for organ transplants live in special facilities to ensure they are disease-free.
Despite this, porcine cytomegalovirus was detected in Bennett’s blood after the transplant.
While the virus does not infect human cells, it did infect transplanted organs, possibly causing his death.
Montgomery said that for the two most recent xenotransplants, they used a more sensitive screening procedure that could detect low levels of the virus.
They have also developed specialized screening methods to monitor the spread of other pig diseases.
Montgomery hopes that phase 1 clinical trials of heart xenografts will be conducted within the next few years.
At the same time, he said that his team will focus on collecting as much data as possible to perform surgery on deceased humans and extend the observation period.
"Seeing a pig's heart beating and working in a human chest is one of the most incredible things, and I am deeply honored to be able to witness it in my lifetime." Montgomery said, "This is a completely new field."
