Full Breakdown
Scientists Revive Pig Kidneys After Year-Long Vitrification
By Drooid · · How we work
Breakthrough Overview
Researchers at the University of Minnesota reported that pig kidneys frozen for more than a year using vitrification were successfully thawed, transplanted into recipient pigs, and restored normal urine production. The study, posted as a pre-print on bioRxiv, demonstrates that organs can survive prolonged cryogenic storage and regain functional blood flow after rewarming.
Research Background
The team, led by transplant surgeon Erik Finger, built on earlier work that included rat-kidney transplants published in 2023 and a 2025 experiment in which pig kidneys were frozen for only ten days before transplantation. The new experiment extends the viable storage window far beyond the typical 36-hour limit for human kidneys and the six-hour limit for hearts or lungs, constraints that keep over 100,000 Americans on organ waiting lists.
Technical Method and Results
The researchers employed vitrification, immersing kidneys in a cryoprotective agent (CPA) enriched with iron-oxide nanoparticles developed with bioengineer John Bischof. Organs were cooled to –238 °F (–150 °C) to achieve a glass-like state, then held at –184 °F (–120 °C), a temperature the team says can remain stable “indefinitely.” Controlled activation of the nanoparticles during rewarming reduced thermal damage, allowing the kidneys to regain normal coloration and produce urine in the test pigs—key indicators of restored function.
Official Statements & Future Outlook
Erik Finger described the result as “a big deal” for transplantation medicine. Harvard Medical School professor Mehmet Toner, deputy director of the NSF-funded Engineering Research Center for Advanced Technologies for the Preservation of Biological Systems (ATP-Bio), said the ability to safely pause biological time in a complex organ could enable transformative change in the field. The researchers cautioned that scaling the process to human organs will require solving integrated challenges in cooling, CPA stability, transport, and toxicity.
Verbatim Quotes
- “Ten years ago […] I wouldn’t say I had high hopes it was actually going to work,” — Erik Finger, transplant surgeon