Application of biocompatible custom ceria nanoparticles in improving the quality of liver grafts for transplantation

Liver transplantation (LT), an ultimate and vital method for treating end-stage liver disease, is often accompanied by ischemia-reperfusion injury (IRI) resulting from warm or cold ischemia of the donor liver. Organ protection techniques are used to improve the quality of liver grafts (from retrieval to implantation). Reactive oxygen species (ROS) cause oxidative stress, which is considered a crucial factor in IRI after LT. Nano antioxidants capable of scavenging ROS alleviate IRI in multiple types of organs and tissues. In this study, we synthesized ceria nanoparticles (NPs) with antioxidant properties using a pyrolysis method and covered them with phospholipid-polyethylene glycol to improve their biocompatibility in vivo. We investigated the potential organ-protective effect of ceria NPs and the underlying mechanisms. Ceria NPs promoted liver function recovery after LT by attenuating IRI in liver grafts in vivo. The protective effect of ceria NPs on liver grafts was investigated by applying hypothermic oxygenated machine perfusion ex vivo. Ceria NPs attenuated hypoxia reoxygenation- or H₂O₂-induced hepatocyte injury by enhancing mitochondrial activity and ROS scavenging in vitro. These effects may be associated with the activation of the nuclear factor erythroid-derived 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)/heme oxygenase 1 (HO-1) signaling pathway. In conclusion, ceria NPs may serve as a promising antioxidant agent for the treatment of hepatic IRI after LT.