Normothermic Machine Perfusion in Liver Transplantation: Multifaceted Utility and Future Perspectives for Clinical Implementation in Japan

Abstract

Donor organ shortage in Japan remains unsolved. In Western countries, the number of liver transplantations substantially increased following the introduction of machine perfusion for grafts from extended-criteria donors. Normothermic machine perfusion (NMP), which maintains the graft under physiologic conditions ex vivo, allows prolonged preservation and real-time functional assessment, thereby facilitating safer graft selection. In addition, NMP attenuates ischemia-reperfusion injury, reduces early graft dysfunction, and enables planned daytime surgery, contributing to improved transplantation workflows.

In Japan, although the annual number of deceased-donor liver transplants has recently exceeded 100 cases, considerable challenges remain, including logistic constraints and the underutilization of grafts from extended-criteria donors. To address these issues, five institutions are planning the first phase I/II clinical trial of NMP in Japan, supported by the Ministry of Health, Labor, and Welfare (grant no: 24CA2038, 2024), with the anticipation that NMP will become a key technology for expanding organ utilization and ensuring the long-term sustainability of liver transplantation in Japan.