Scientists find a way to store donor livers for more than a day

The livers harvested for transplant can be safely stored in suspended animation for triple the duration that currently possible, thanks to a novel ‘supercooling’ technology developed by scientists. The technique developed by a team of biomedical researchers at the Massachusetts General Hospital (MGH) and Harvard Medical School, including two who are of Indian-descent, could be a big boon for those on waiting lists for liver transplant.

The new technique reported by the team led by Korkut Uygun, the Turkish-born biomedical scientist at MGH, in the latest issue of Nature Biotechnology journal on Monday, makes storing of organs meant for transplantation for longer periods of time possible and this extra time saves transplant surgeons from rushing through the procedure. The protocol that they developed can help preserve a human liver outside the body for nearly 27 hours as against the current clinical average of nine hours, the scientists claimed.

Their protocol, still in its early stages, could help increase the pool of donor organs available and thus reduce organ discard and the cost of organ transplant. Besides, it can make transplants successful by repairing organ injury during removal and transport and by assessing organ viability before transplant. Most of these are currently impossible for want of time.

The absence of technology to preserve organs for more than a few hours has been one of the fundamental causes of donor organ shortage crisis. According to the World Health Organization, less than 10 per cent of global need for organ transplantation is currently met even though thousands of potentially transplantable organs are discarded every year. It is said that for every four waitlist patients who do not receive a new liver in time, three livers are discarded. One of the key reasons for this is the limited time available for preserving organs.

It is not for the first time that Uygun’s team developed a supercooling technology for organ preservation. In 2014, they successfully demonstrated that rat livers can be stored if they were kept at minus 6 degree Celsius. But scaling the technology to human livers threw up a number of challenges.

One of them is the formation of ice during cryopreservation of the organ. While the scientists perfected the protocol for the rodent organ, they found that extending the same to human livers is impossible as the human liver is 200 times larger than that of rat. To keep the organ intact, they required to prevent the formation of ice during the storage. But the larger size of the human liver made it impossible for them to supercool it without ice crystals being formed inside the harvested organ.

In addition, for successful supercooling preservation, livers must be preconditioned with chemical agents that protect it from the cold which is much harder to achieve in large sized organs.

The group – which included among others India-born technicians Sonal Nagpal and Peony Banik, both working with the Centre for Engineering in Medicine at MGH – managed to overcome these hurdles. They came up with better methods that can stabilise supercooling of large volumes and applied those principles to whole human livers.

According to the scientists, this new technique leverages machine perfusion technology to evenly precondition the organs before subzero storage and to bring the organs back from their state of suspended animation. With this protocol that employs an integrated constellation of technologies, they were able to successfully supercool human livers for nearly 27 hours.

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