The current supply of viable donor livers isn’t enough to meet the demand caused by rising liver disease rates. The way we store donor livers today – in cold storage – means many livers must be discarded. The Consortium for Organ Preservation in Europe (COPE) clinical trial team at the Nuffield Department of Surgical Sciences, supported by CSM statistician Susan Dutton, tested whether maintaining livers at body temperature would mean fewer livers are discarded - so that more transplants can be carried out - and whether patients do better after transplant. The results were published online this week in Nature.
This research has the potential to profoundly improve liver transplants globally. - Dr David Nasralla
Many potential donor livers are deemed too high risk, because they are more susceptible to damage during the refrigeration used to preserve organs during transport between where the liver is donated and where the potential recipient is. Once a liver is in cold storage, normal cellular activity is suppressed, so we can’t test the liver’s viability until it has been transplanted and warmed up again. Instead, we could keep donor livers at body temperature and give them oxygenated blood, medication, and nutrients, as if they were on life support, using a process called normothermic machine perfusion. Livers can be kept like this for up to 24 hours. The process could one day allow us to monitor viability and even treat and repair the livers if needed.
David Nasralla and colleagues conducted the first randomized trial comparing conventional cold storage with normothermic machine perfusion in 220 liver transplant patients. They measured biomarkers of liver damage and found a 50% drop in graft injury and a 50% lower rate of organ discard when normothermic preservation was used instead of cold storage, even though the livers were preserved for 54% longer before transplant. In the year after transplant, the team found no significant differences in rates of bile duct complication, or graft and patient survival rates (as predicted by a clinically accepted biomarkers) between the different preservation approaches. "This research has the potential to profoundly improve liver transplants globally," says Dr Nasralla.
The device used for normothermic machine preservation was developed by OrganOx Ltd, a MedTech business spun-out from the University of Oxford as a result of a collaboration between Peter Friend (Nuffield Department of Surgical Sciences) and Constantin Coussios (Institute of Biomedical Engineering).
“It has been a while since proper innovation boosted organ transplantation,” writes Stefan Schneeberger in an accompanying Nature News & Views article. He explains that normothermic machine perfusion may substantially increase viable donor organ numbers and allow more time for transplants to occur.
COPE is funded by a European Commission FP7 Award and is the official organ preservation task force of the European Society for Organ Transplantation (ESOT).