New supercooling technique preserves transplant organs for four days

Researchers have used a glucose substance to supercool transplant organs at -6 degrees Celsius, potentially opening up a longer window for transplants.

Researchers at the Centre for Engineering in Medicine at the Massachusetts General Hospital in the US have developed a new supercooling technique that preserves organs outside the body for up to four days after being harvested.

Medics currently use a chemical solution and cold temperatures to keep organs viable for up to 24 hours. This timeframe is not always enough to prep the receiving patient and doesn’t allow intercontinental transplants.

The researchers tested the new method in rat livers, which usually last for about 12 hours after being harvested.

The new supercooling technique involves pumping a glucose compound (3-0-methyl-D-glucose) through the organ to keep it functioning outside the body and delay cell death, explained Liat Clark at Wired UK. The substance provides nutrients to the organ and also acts as a sort of anti-freezing barrier, keeping the cell membranes cool, but not frozen.

The livers were cooled to -6 degrees Celsius and kept supercooled either for 72 or 96 hours. To rewarm the organs the researchers used machine perfusion, a way of delivering nutrients and oxygen to blood vessels in tissues outside the body. They then transplanted the livers into rats.

Clark reports that the rodents that received the livers that remained supercooled for three days responded well to the transplant and survived for at least three months. The rats who got the livers that were supercooled for four days didn’t do as well—the survival rates dropped 58%.

Keeping organs human outside the body for more than 24 hours has been quite a challenge, as these start to decompose as soon as they are out of the body and freezing them can damage the tissue.

The researchers have explained that although promising, these results were achieved only in rats and more studies in larger animals need to be conducted before human trials.

“The longer we are able to store donated organs, the better the chance the patient will find the best match possible, with both doctors and patients fully prepared for surgery,” said tissue engineer Rosemarie Hunziker, program director of Tissue Engineering and Regenerative Medicine at National Institute of Biomedical Imaging and Bioengineering in the US, in a release. “This is a critically important step in advancing the practice of organ storage for transplantation.”