Scientists have developed an organ preservation system that could significantly improve the success rate of liver transplants, while enabling the organs to be preserved for longer before transplant.

The system, which has been successful in animal studies, uses what is known as machine perfusion to pump a cell-free, cooled, oxygen-rich fluid into the liver while it is waiting to be transplanted.

This keeps the liver fed with oxygen as if it were still in the body, and so maintains its quality for longer than with the traditional organ storage and transport system.

As a result, the system has been demonstrated to have a considerably higher success rate, suggesting it could be used to significantly increase the number of healthy, quality livers available to patients on the transplant waiting list.

At present, organs are stored at a low temperature to keep them in a transplantable state for as long as possible.

“Standard practice is to use a method called cold static preservation, which uses tissue cooling to slow down metabolism with the aim of reducing the demand for oxygen and thus protecting cells from death,” said study senior investigator Dr Paulo Fontes, a University of Pittsburgh School of Medicine transplant surgeon; associate professor at the Starzl Transplantation Institute and deputy director of the McGowan Institute, all of which were involved in the system’s development.

“In our new system, we pump a special fluid designed to deliver oxygen to the liver, creating an environment that supports normal function. The integrity of the cells and vital metabolic activity is sustained for eventual transplantation of the organ.”

Although the system has only been tested on pigs at present, the results have been extremely positive.

The researchers transplanted a total of twelve pigs with livers, six of which were stored using the new preservation system and six with the traditional storage system.

The livers in question were kept in their respective systems for nine hours prior to transplant, which is the average time it takes to recover, transport and prep for transplantation.

Of the pigs transplanted with traditionally stored livers, only 33% survived. However, the pigs receiving livers using the new machine perfusion system all survived.

These livers also performed better than the surviving cold static livers; they had higher bile production, higher oxygen levels and were found to be better preserved.

“It was immediately obvious to us that the pigs who received MP livers looked much healthier and easily moved around their pens just hours after they woke up from the surgery,” added Fontes.

“They didn’t look as ill as the animals treated with standard cold preservation. It was amazing.”

While currently only demonstrated in pigs, the scientists believe that the system could be a game-changer for human organ preservation.

“This system has great potential to enhance our current standards for organ preservation, which should translate into more patients getting a life-saving procedure with potentially better outcomes,” explained Fontes.

“Not only that, we have hopes of a faster recovery because the liver could be less likely to become injured due to a lack of oxygen.”

The researchers plan to launch a clinical trial on human organs later this year, which, if successful, could eventually lead to the system becoming standard practice.