Science triples the storage time of human donor livers

Recent study has created a breakthrough research by extending the amount of time required to store a human liver for transplantation. The discovery was made possible by modifying the previous protocol to extend the viability of rat livers.

Studies indicate human livers are viable for an average of nine hours, the latest research has however developed a new method of preservation which helps in maintaining the liver tissue for up to 27 hours. This latest discovery has given patients as well as transplant doctors a longer timeframe to work with.

“Delivering viable organs to matching recipients within the window of viability can often be the most challenging aspect of organ transplantation,” explained Seila Selimovic, Ph.D., director of NIBIB’s Engineered Tissues program. “By giving doctors and patients more time, this research could someday affect thousands of patients who are waiting for liver transplants.”

The study has been supported by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK), they are parts of the National Institutes of Health.

Since human cells are sensitive, donor livers need to be stored above freezing temperature of 4 degree Celsius. Doctors could therefore preserve a human liver only for nine hours, any time after the chances of a successful transplant begin to decrease. It is because of this small timeframe that organs cannot be transported to compatible patients who stay at far away locations.

Previous research in this field has also worked with rat livers, however the experiments have been unsuccessful when implemented to human livers, which are 200 times larger. Scientists believe it is the size difference that ultimately increases the risk of ice crystals which forms a  heterogenous ice nucleation, thus making the organ unusable for transplantation.

“With supercooling, as the volume increases it becomes exponentially more difficult to prevent ice formation at sub-zero temperatures,” commented Reinier de Vries, M.D., a research fellow in surgery. “Before, there were a lot of experts who said, ‘well this is amazing in small rats, but it will not work in human organs,’ and now we have successfully scaled it up 200 times from rat to human livers using a combination of technologies.”

The study ultimately became a two-step program: in the first step, scientists limited the contact of storage liquid to air. This was mainly because scientists discovered that ice crystals were generated greatly when the solution came in contact with air. In the next step, scientists added two ingredients as protective solution in order to help protect hepatocytes. This further developed in creating a new method for delivering preservation solution to the liver.

The new method will thus help in delivering organs to greater distances and critically ill patients will in return benefit from the transplantations.