Researchers at the University of Minnesota have revived pig kidneys after storing them at minus 150 degrees Celsius for months, with some kept for longer than a year, according to MIT 테크놀로지 리뷰. The kidneys were warmed back up and regained function, the outlet reports — a first for organs held at such temperatures.
The work has not yet been peer reviewed. The findings were posted on bioRxiv, a preprint server where research is shared before formal review.
Why it matters
Organ transplantation runs on a clock. Kidneys and other organs deteriorate within hours once removed from a donor, which forces surgeons to match organs to patients in a rush and leaves many usable organs unused. If organs could be banked for months or years, the logistics of matching donors to recipients would change fundamentally — organs could wait for the right patient rather than the other way around.
The Minnesota team used pig kidneys chosen to be similar in size to human kidneys, and the researchers say their goal is to apply the same approach to human organs, MIT 테크놀로지 리뷰 reports.
How the kidneys were preserved
The central problem in freezing organs is ice. As tissue cools, water inside cells can form ice crystals that tear the delicate structures apart, leaving the organ unusable no matter how carefully it is thawed.
To avoid that, the researchers turned to a technique called vitrification. Rather than letting the tissue freeze into ice, the process drives it into a glass-like, non-crystalline state in which no crystals form. The kidneys were held in that state at minus 150 degrees Celsius for extended periods.
After rewarming, the team assessed the organs with a mechanical device and then transplanted them into pigs. According to MIT 테크놀로지 리뷰, the kidneys returned to their normal color and began producing urine — a key indicator that they had started working again.
Erik Finger, a transplant surgeon at the University of Minnesota who co-led the research, told the outlet he had not expected much of the technique a decade ago. He said that after completing the final transplant in the series, he left the operating room telling colleagues it was a major achievement.
The limits of the result
The revived kidneys did not function perfectly, and it is not yet known whether they could sustain life over the long term, MIT 테크놀로지 리뷰 reports. Those gaps matter: producing urine is a sign of restored activity, but it is not the same as demonstrating that a preserved organ can reliably take over a patient's kidney function for years.
Peer review will also test the claims. Preprints allow researchers to share results quickly, but the findings have not yet been examined by independent scientists in the formal publication process.
Even so, researchers in the field are treating the experiment as a significant milestone, according to the outlet. The result moves vitrification of large organs from theory toward something that has been demonstrated in an animal model, at least in the short term.
What to watch: whether the Minnesota team and others can extend the approach to human organs, and whether longer follow-up shows that rewarmed kidneys can support life, not just resume basic activity.
