Preserving livers at body temperature may improve transplant outcomes and increase viable donor liver numbers, thereby lowering waiting list mortality rates, reports a paper published online this week in Nature.
Rising liver disease rates have rendered the supply of viable donor organs inadequate. Many potential donor livers are deemed too high risk, being more susceptible to damage during the refrigeration used to preserve organs mid-transplant. Liver viability cannot be gauged during cold storage, as normal cellular activity is suppressed. A promising alternative lies in maintaining donor livers at body temperature, supplying the organs with oxygenated blood, medications and nutrients - much like a patient on life support - through a process called normothermic machine perfusion. Livers can be kept in this manner for 24 hours, and the process could one day enable the monitoring of viability along with treatment and repair as needed.
David Nasralla and colleagues conduct the first randomized trial comparing conventional cold storage with normothermic machine perfusion in 220 liver transplant patients. Measuring biomarkers of liver damage, they found a 50% reduction in graft injury in normothermic preservation compared with cold storage, despite a 54% increase in the mean duration over which livers were preserved and a 50% lower rate of organ discard. In addition, in the year after transplant, the authors found no significant differences in rates of bile duct complication, or graft and patient survival rates (as predicted by a clinically accepted biomarker), between preservation approaches.
"The ability to preserve an organ under close-to-normal conditions could be instrumental in advancing not only liver transplantation, but also liver surgery and organ care," writes Stefan Schneeberger in an accompanying News & Views article.