New technology allows human donor livers to be cooled to subzero temperatures without freezing and can triple the critical period a donor organ remains viable during delivery from a donor to a recipient.
The development should significantly expand the availability of healthy livers for transplantation, improve organ utilisation, and reduce some of the time pressures on surgical teams.
There is a worldwide shortage of donor organs shortage and in the U.S. for example, currently only about 36,500 out of 730,000 patients with advanced organ disease receive a life-saving organ transplant in a twelve month period.
The new technology has been developed by Harvard Medical School researchers based at the Center for Engineering in Medicine at Massachusetts General Hospital. The research team includes Reiner de Vries, HMS research fellow in surgery, Shannon Tessier, HMS instructor in surgery, and M. Korkut Uygun, HMS associate professor of surgery.
Time is of the essence and under normal conditions a donor human liver is only able to be maintained for approximately nine hours outside the body while being stored on ice in a preservative solution at temperatures ranging from 4° to 8°C before the liver tissues begin to deteriorate.
The research team was initially able to demonstrate via rat livers that it is possible to cool them to -6°C without causing damage to the liver tissues thus extending preservation time from mere hours to more than a day.
Prior to supercooling, livers are conditioned to protect them from the cold with a preservative solution that is delivered via machine perfusion (circulation), a technique already in use to preserve organs for transplantation. Perfusion ensures that the preservative solution is evenly distributed throughout the organ. Donated livers can then be transported at -4°C (24.8° F). At the transplantation surgery theatre, machine perfusion is again used to carefully warm the livers and bring them out of their state of cooled suspension. Using this technique, the researchers have been able to extend the out-of-body viability period for livers for up to 27 hours.
The reality is that when an organ becomes available there may not be an ideal recipient match in close proximity and with the advent of this new technology a wider search over a longer period can now be made to bring about suitable pairings.