A Novel Evaluation System for Whole-Organ-engineered Liver Graft by Ex Vivo Application to a Highly Reproducible Hepatic Failure Rat Model

In recent years, studies on liver graft construction using the decellularized liver as a template for transplantation therapy have attracted much attention. However, the therapeutic effect of constructed liver grafts in hepatic failure has not been evaluated. Therefore, we aimed to develop a novel evaluation system demonstrating the curative effect of a constructed liver graft in animals with hepatic failure. First, we developed a highly reproducible rat model of hepatic failure by combining 80% partial hepatectomy with warm ischemia. In this model, severity could be controlled by the warm ischemic period. We also constructed a liver graft by recellularization of decellularized liver, and confirmed the ammonia metabolic function in the graft in vitro as one of the most important functions for recovery from hepatic failure. The graft was then applied to our developed hepatic failure rat model using a blood extracorporeal circulation system. In this application, the graft metabolized the ammonia in the blood of animals with hepatic failure and was thus suggested to be effective for the treatment of hepatic failure. In summary, a novel evaluation system for whole-organ-engineered liver graft as a preliminary stage of transplantation was developed. This system was expected to provide much information about the curative effect of a constructed liver graft.