Supercooled pig kidneys successfully transplanted after days of storage

Researchers have successfully transplanted supercooled pig kidneys after storing them for up to three days, a breakthrough that could dramatically extend the time available for organ transport and reduce waste. The work, led by Matthew Powell-Palm at Texas A&M University, used a device that cools organs to -4°C (25°F) without ice formation, avoiding the damage caused by freezing.

The study affects the more than 104,000 people waiting for a kidney transplant in the US alone, where an estimated 17 die each day. Currently, kidneys can be stored on ice for only about 24 hours, and roughly one in three donated kidneys is discarded, often because they degrade before reaching a recipient. Extending storage time could save many of these organs.

In the experiment, pig kidneys were supercooled for 24, 48, or 72 hours and then transplanted back into the same animals. The 24-hour supercooled kidneys began producing urine immediately and showed normal function within about 10 days—faster than kidneys stored on ice for 24 hours. Even after 72 hours, recovery was quicker than the current gold standard of ice storage. Over 30 days, the pigs grew by about 30%, and the transplanted kidneys nearly doubled in size to compensate. One pig was monitored for 200 days, and its kidney remained healthy.

The device works by keeping the organ submerged at constant pressure, preventing ice formation without cryoprotectants, which can have side effects. Powell-Palm presented the findings at the American Transplant Congress in Boston last month. The team hopes this approach could eventually be used for human kidneys, potentially easing the organ shortage. Further research is needed before clinical trials can begin.