The promise of organ perfusion
Globally, tens of thousands of people are in need of a liver transplant, but despite this growing need, thousands of donated livers are discarded each year. This is in part due to the inability to evaluate high-risk livers from donors with other health complications or donors whose hearts stopped beating. Conventional cold storage of organs slows cellular metabolism to preserve the organ but also limits functional assessment.
In a randomized trial of 220 liver transplants published in Nature this month (Nasralla, et al.) , researchers tested an alternative to cold storage, normothermic machine perfusion. The device, made by OrganOx, perfuses the liver with oxygenated blood and nutrients while maintaining the organ at body temperature, 37°C. Transplanted livers maintained on the device showed 50% lower level of biomarkers associated with injury and had a 50% lower rate of discard. Further analysis of the results suggests that livers from the high-risk donors whose hearts stopped beating had better outcomes than donor organs in cold storage and lower risk donors on machine perfusion.
A second study (Warnecke, et al.) was also published this month assessing the effect of preservation with machine perfusion, this time in lungs. They found preserving lungs on the Organ Care System Lung device (TransMedics) was as safe and effective as cold storage and had lower incidence of severe complications following transplant.
Machine perfusion is not only an important step towards expanding the donor pool and ending the organ shortage, but observing organ functionality in real time and making clinical decisions opens the door for more other advances, like rehabilitating organs, possibly synergizing with emerging gene therapies, drugs and other technologies.
More news coverage from Nature can be found here, including comments from the Organ Preservation Alliance. - Dr. Kate Franz