Vitrified pig kidneys stored at -150°C for 12 months regain urine production after nanoparticle rewarming and transplant

Researchers loaded pig kidneys with cryoprotectants then iron oxide nanoparticles, vitrified them at -150°C, and stored them up to 13 months. Rewarming used radiofrequency fields to trigger uniform nanoparticle heating. Post-rewarm machine perfusion and orthotopic transplant showed restored color and urine output in multiple cases.

The preprint reports functional metrics but lacks peer review and long-term recipient survival data. Kidneys met short-term viability markers yet exhibited incomplete recovery compared with fresh controls. Prior vitrification attempts on whole organs failed at scale due to ice formation and toxic cryoprotectant loads; nanoparticle induction addresses thermal gradients.

This extends organ banking timelines beyond the current 24-36 hour cold ischemia limit, enabling better HLA matching and recipient conditioning. Operational impact requires demonstration of sustained life support and scalable human protocols. Next steps include multi-center pig survival studies and ex-vivo human kidney tests.

Regulatory pathways will hinge on 30-day graft survival thresholds and absence of nanoparticle residue toxicity in GLP studies.