According to American doctors, a kidney transplanted from a pig worked in a patient's body for 271 days. This is the longest record so far.
Patient Tim Andrews said that this transplant gave him a new 'hope' and he did not need to go to the hospital and get his blood cleaned with a dialysis machine for several months.
The team at Mass General Brigham Hospital says their work shows that pig organs can be used as a temporary 'bridge' until a human kidney becomes available.
However, the pig's kidney eventually stopped working and had to be removed. Andrews then had to undergo dialysis for some time until he found a donor.
Due to shortage of organs for transplant, doctors and scientists are exploring the methods of xenotransplantation, in which organs from other animals are used.
Nearly 1 lakh people are waiting for a kidney transplant in America, while only 25,000 transplants take place every year. More than 7,000 people in Britain are on the list for a kidney transplant.
Andrews was told it could take seven years before his turn came. But people undergoing dialysis live only five years on average. He said, "I had a little less time. It becomes very frustrating."
But he described the idea of pig kidney transplants as 'hopeful' and 'a light at the end of a dark tunnel'. He said, "Hope is the biggest thing that gives us the opportunity to be free from the machine and live our lives."
Pigs are considered the best animal for xenotransplantation. The shape of its organs is almost correct and humans have many years of experience in raising them.
The human body will immediately recognize the organ as foreign and launch an immune response that will destroy the kidney. Within a few minutes, holes will start forming in it, every cell will be damaged and the organ will turn black due to blood clotting from inside.
So researchers developed the 'Yucatan Miniature Pig'. 69 types of changes have been made in their genes, so that their organs can be made 'suitable for the human body'. These changes remove some of the characteristics of pig cells that our immune system recognizes and attacks. Some human DNA is also added, which creates a camouflage that helps the pig's tissue hide from the human immune system. Apart from this, to prevent infection, changes are also made in the pig's DNA to inactivate the hidden virus.
Due to type 2 diabetes, Andrews developed severe kidney disease and his kidneys were failing. When he underwent xenotransplantation on 25 January 2025, he was 66 years old. According to information recently published in the medical journal The Lancet, the transplanted pig's kidney started working immediately. This kidney continued to function for 271 days. After this, he was fired in October the same year. After this, Tim had to undergo dialysis for 82 days, until he received a kidney from a donor in January this year. That kidney is working well now.
Dr. Leonardo Riella of Mass General Brigham's Center for Transplantation Sciences said 'we are in a crisis' due to the shortage of organs available for transplant. He said, "We are working very hard to provide hope. We really think that xenotransplantation can be an option for patients who do not have a donor. This allows us to potentially bypass dialysis and get them to a transplant."
There were initially signs that the immune system was rejecting Andrews' organ, but this was successfully treated by changing his medication. However, after about six months the blood vessels in the kidney started getting damaged and the organ became swollen and then started to stop working. The exact reason for this is unclear as there was no sign of antibody attack on the pig kidneys.
"This case illustrates both the potential and the challenges of clinical kidney xenotransplantation," the doctors said in their article in The Lancet.
