A new supercooling technique keeps rat livers alive 3 times longer than previous techniques, raising hopes for reducing shortages of human transplant organs.
According to the AFP, the method involves cooling the livers while flushing them with oxygen and nutrients, and preserving them in a solution that allows them to be stored below 0°C without freezing or its associated cell damage. The organ is supercooled to –6°C and can be stored for 3–4 days. A machine (see picture) helps to rewarm the organ and prepare it for transplantation.
A supercooled rat liver in preservation solution in the machine perfusion system
All rats given livers supercooled for 72 hours were healthy after 3 months, a benchmark for survival. Of rats who received livers stored for 96 hours, 58% survived to the 3-month mark, Tim Berendsen et al. reported on June 29 in Nature Medicine. Rats that received transplant livers preserved with current methods survived only for hours or days.
“To our knowledge, this is the longest preservation time with subsequent successful transplantation achieved to date,” the study’s senior author, Korkut Uygun (Massachusetts General Hospital), told AFP. “If we can do this with human organs, we could share organs globally, helping to alleviate the worldwide organ shortage.”
“The next step will be to conduct similar studies in larger animals,” Rosemarie Hunziker, of the National Institute of Biomedical Imaging and Bioengineering (NBIB), said in a press release. The method will have to be thoroughly tested and refined before it can be considered for use in humans.
The Boston Globe explained that organs can only stay alive outside of the body from 5 to 24 hours, depending on the organ, before they begin to deteriorate. Since the 1980s, donor organs have been preserved at temperatures at or just above freezing in a solution that reduces their metabolism and deterioration. have previously attempted to cool organs to below 0°C without any success.
Some 120,000 people are waiting on donor organs in the United States alone, says the NBIB. They explained that extending the time a liver can survive outside the body would allow more time to prepare the patient and ease logistics at the donor hospital site, reduce the urgency of rushing the organ to its destination, and expand the donation area to allow for transcontinental and intercontinental transplantations. This would boost the chances of patients finding better donor organ matches, and reduce costs, the NBIB explains.
The BBC wrote that if the technique works on human organs, it could to transform the process of organ donation. Uygun told the BBC that the technique could lead to donated organs being shared around the world. He added that organs that are normally not considered for transplantation might be suitable if they were preserved by supercooling.