Transplanted pig kidney works in US man's body for record 271 days

Health and science correspondent.

Key points

• In the US, around 100, 000 individuals are waiting for a kidney while only 25, 000 transplants occur each year.
• He was 66 years old when he had the xenotransplant on January 25, 2025.
• The kidney continued to function for 271 days until it was removed in October that year.
• Dr Leonardo Riella, from the centre for transplantation sciences at Mass General Brigham remarked the shortage of organs available for transplant meant " we are in a crisis".
• A kidney transplanted from a pig has worked inside a patient for 271 days – the longest on record, say US doctors.

For context, a kidney transplanted from a pig has worked inside a patient for 271 days – the longest on record, say US doctors.

Tim Andrews remarked the transplant provided him "hope" and spared him months of needing to go to hospital to have his blood filtered by a dialysis machine.

Notably, the team at Mass General Brigham hospital say their work demonstrates pig organs can be employed as a "bridge" until a human transplant becomes available.

But the pig organ eventually failed and was removed so Andrews needed a short bout of dialysis before a donor was discovered.

Doctors and scientists are exploring xenotransplantation – using organs from other species – due to shortages of organs for transplants.

In the US, around 100, 000 individuals are waiting for a kidney while only 25, 000 transplants occur each year. More than 7, 000 individuals in the UK are on the kidney transplant list.

Andrews was informed it could take seven years to secure to the top of the list, but that individuals live only five years, on average, on dialysis.

"I had a little bit of a shortage of time. It becomes very depressing, " he remarked.

But he described the idea of a pig transplant as "hope" and the "light at the end of the tunnel".

"Hope is the biggest thing, the chance to be free from the machine and live your life."

Pigs are seen as the ideal animal for xenotransplantation. Their organs are roughly the right size and there have been years of experience farming them.

But you cannot just pop down to the farm and take a kidney from a pig and put it into a person. The human body would immediately identify the organ as foreign and launch a devastating immune assault that would destroy the kidney. It would turn black in minutes as holes are ripped in every cell and the organ clots from the inside.

So researchers have developed Yucatan miniature pigs that have gone through 69 genomic modifications to "humanise" their organs.

These modifications strip out some features of pig cells that our immune system spots and attacks; add some human DNA that acts like camouflage netting to support hide the pig tissue from the immune system and further tweaks disable viruses that hide inside pig DNA to prevent infection. Are pigs the future of organ transplants?

Andrews had end stage kidney disease since of type 2 diabetes and his kidney's were failing.

Notably, the transplanted pig kidney worked immediately, according to details just published in the Lancet medical journal, external.

Notably, the kidney continued to function for 271 days until it was removed in October that year. Tim then needed dialysis for 82 days until he had an organ from a donor in January of this year. That organ has been working well.

"We are working really hard to bring hope and we truly feel that xenotransplantation can be an alternative for patients who don't have a living donor where we could potentially bypass dialysis and get them to a transplant, " he remarked. Man who received first pig kidney transplant dies.

There were early signs Andrews' organ was being rejected by the immune system, but that was successfully treated by adjusting his medication.

After around six months the blood vessels in the kidney kicked off to become damaged and the organ inflamed and then it began to fail, nevertheless.

It is not clear exactly why as there were no signs of antibodies attacking the pig kidney.

In their Lancet write-up the doctors state: "This case illustrates both the promise and the remaining challenges of clinical kidney xenotransplantation."

In short, transplanted pig kidney works in US man' s body for record 271 days is the central thread here, and readers can expect follow-up reporting as the picture becomes clearer.