David Bennett, a 57-year-old man from the US, received the world's first pig heart transplant（移植）on January 7th, 2022. He died two months later. It may sound like a failure, but it actually is a big step forward for xenotransplantation（异种器官移植）.
Xenotransplantation has been a hot topic in medical research for many years. Doctors and scientists look for ways to solve the big problem of organ（器官）transplant waiting lists. In the US alone, over 100,000 patients are on a list waiting for new organs. Many will die before getting their chance to receive a heart, a kidney（肾）or other important organs. As a result, medical science has turned to animal organs.
There have been few successful xenotransplantation cases since the early 20th century. Usually, patients' bodies reject（排斥）the animal organs. Bennett lived much longer than other xenotransplantation patients. That's because the scientists removed pig genes（基因）that would cause fast rejection. Then they added human genes to help the body accept the organ.
In fact, Bennett's case was not the only success. "A lot of new information that doctors got through other organ transplants will come out. The development of this field will benefit from it and move forward at a faster speed." Muhammad Mohiuddin, director of the transplant program, told The Guardian.
