Kidney transplanted into a rat after being cryopreserved for 100 days
Researchers performed the first successful organ transplant in animals after long-term storage at ultra-low temperatures.Researchers from the University of Minnesota demonstrated the operation of technology for long-term cryopreservation of organs for subsequent transplantation. A kidney was frozen, heated and successfully transplanted into a rat. After transplantation, the organ's function was fully restored.
The researchers developed a specialized nanoheating process that quickly and evenly heats the organ from the inside, not just on its surface. They used iron oxide nanoparticles dispersed in a cryoprotectant solution, which is flushed through the blood vessels of the organ. These particles act as tiny heaters when activated by noninvasive electromagnetic waves.
The researchers conducted several separate experiments. Rat kidneys were frozen and subjected to prolonged storage for up to 100 days. They were then warmed with iron nanoparticles, cleared of cryoprotective fluids, and transplanted into rats. In five recipients, kidney function fully recovered within 30 days after surgery without additional interventions.
"During the first two to three weeks, the kidneys did not function at full capacity, but by three weeks they had recovered. By one month, they were fully functioning kidneys that were completely indistinguishable from 'fresh' organ transplants," Eric Fringer, a transplant surgeon and professor of surgery at the University of Minnesota Medical School.
The researchers note that there will be many more interventions, including supportive medications and dialysis, to help the kidney in the weeks immediately following transplantation in humans. None of this has been done with rats, yet the surgery has been successful.
Currently, about 20% of donor kidneys are not used for transplantation because these organs cannot be kept on ice longer than a few hours and do not reach recipients in time. The creation of long-term storage technology will help preserve and utilize this resource. Researchers have shown that the proposed solution can be applied to larger organs as well. They plan to conduct their next experiments on a pig, a closer model organism to humans.