Pig Kidney Frozen for a Year Successfully Revived

U.S. scientists have succeeded for the first time in the world in reviving a pig kidney that had been frozen and stored for more than a year at minus 150 degrees Celsius. The achievement could dramatically expand transplant opportunities for patients waiting for organs by making long-term organ storage possible.

The researchers cooled the kidney using vitrification—a process that turns it into a glass-like state—and kept it frozen for an extended period. The pig kidney used in this experiment is similar in size to a human kidney.

After rewarming, the kidney underwent functional testing on a machine before being transplanted into a pig. The transplanted kidney regained its color and produced urine, showing key signs that it was working.

The study was co-led by Erik Finger, a transplant surgeon at the University of Minnesota. Finger said that even a decade ago, he had not seriously expected the effort to succeed, and after completing the final transplant, he remarked, "This is huge."

The findings have been posted on the preprint server bioRxiv and have not yet undergone peer review. The researchers have not yet demonstrated whether the rewarmed kidney can sustain life over the long term.

Currently, human organs can be preserved for only 24 to 36 hours. "If true organ banking becomes a reality," Finger said, "patients will no longer wait for organs—organs will wait for patients."