New Method by Mass. General Researchers Keeps Organs Alive Outside Body Longer

A supercooled rat liver sits in the preservation solution in the machine perfusion system.
A supercooled rat liver sits in the preservation solution in the machine perfusion system.
Source: Wally Reeves, Korkut Uygun, Maish Yarmush, Harvard University

The scenario plays out often on medical television dramas. Surgeons, in a race against time, rush to transport an organ from one donor to a recipient. They place the healthy organ into a cooler and hope it stays “alive” long enough to be transported. Sometimes they make it, and sometimes they don’t.

Unlike other suspenseful scenes on medical dramas, the rush is real. In reality, organs can only stay alive outside of the body anywhere between 5 to 24 hours—depending on the organ—before they begin to deteriorate. In the US, where more than 120,000 people are waiting for organ transplants, every donated organ is precious and those hours are crucial.

But that rush to transplant could change.

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A new technique, developed by researchers at Massachusetts General Hospital, may extend the life of organs stored outside of the body before transplantation by up to three days longer than any other preservation method.

Using a rat liver model, the researchers found that organs could be preserved longer using four steps. A machine delivers oxygen and a nutrient solution that includes a glucose compound and an “anti-freeze agent” to the organ tissues. This solution administered helps to keep the liver tissue from freezing while protecting the cells and preventing tissue damage.

The organ is then “supercooled” to 21 degrees Fahrenheit. When the organ is ready for use, the machine helps to rewarm the organ and prepare it for transplantation.

For years, researchers have attempted to cool an organ below zero degrees without any success.

“If ice forms, the ice crystals are hazardous to the tissue,” said Bote Bruinsma, a research fellow at Massachusetts General Hospital and co-author of the study.

“When it happened in a liver, it immediately led to non-survival,” he said.

Human livers should be transplanted within 12 hours using the current preservation technique, Bruinsma said.

In their study, published Sunday in the journal Nature Medicine, the researchers were able to store the rat livers for both three and four days using their technique. All of the 12 rats who received transplanted supercooled livers that were stored for three days survived for three months after transplantation, while none of the rats who were given a transplanted liver kept outside the body for the same length of time without the new preservation technique did.

Only half of the rats who were transplanted the supercooled livers that were stored for four days survived.

“It appears that four days is the threshold for the organ,” Bruinsma said. “Around four days, the liver starts to deteriorate to the point where they’re no longer transplantable.”

Every step in their supercooling technique was crucial to keeping the organ and the recipient alive, the researchers found.

While only tested in livers, Bruinsma said it’s likely the method could be adapted to work for other organs as well.

If the method works in humans, it could not only cut the transplant waiting list, but also help to better match a donor to a recipient, Bruinsma said.

“The better the matches, the better the outcome as well,” he said.

Bruinsma and his colleagues are currently testing the preservation method in human livers that are not deemed appropriate for transplantation, without actually transplanting them into patients. Their next step is to test the method in animals with larger livers and to use other organs.