*Purpose: Ferroptosis, a newly discovered programmed cell death platform, due to iron-dependent accumulation of lipid peroxides, has been reported to aggravate ischemia-reperfusion (IR) injury in various organs, including heart, kidney, and intestine. Nevertheless, little is known about the contribution of ferroptosis in liver transplantation. In the current study, we investigated the functional role of ferroptosis signaling during liver cold storage and warm IR, and evaluated its pathogenic effects in mouse and human orthotopic liver transplantation (OLT).

*Methods: Fifty adult human OLT patients were recruited under IRB protocol. Liver graft biopsies (pre-reperfusion and 2h post-reperfusion) were screened based on levels of glutathione peroxidase 4 (GPX4), the key ferroptosis regulator. Hepatocytes and liver sinusoidal endothelial cells (LSECs) isolated from C57BL/6 mice were subjected to cold stress or warm hypoxia/reoxygeneration (H/R). Further, we used ferroptosis inhibitor (ferrostatin-1) in the liver storage solution or in mouse recipients to evaluate its therapeutic effect in OLT settings.

*Results: The GPX4 expression in human liver biopsies negatively correlated with pro-inflammatory host immune cell activation markers. The anti-inflammatory phenotype in high GPX4 recipient group coincided with improved hepatocellular function (decreased AST levels) post-OLT, suggesting ferroptosis inhibition might reduce OLT injury in humans.During cold stress, increased GPX4 expression was observed in cultured murine LSECs but not hepatocytes. In contrast, the hepatocyte GPX4 expression increased during warm H/R, coinciding with increased hypoxia-inducible factor 1-alpha (HIF-1α) levels. In mouse OLT model, the hepatocellular damage was mitigated in liver grafts preserved with ferrostatin-1, a ferroptosis inhibitor. In addition, systemic administration of ferrostatin-1 to recipient mice reduced OLT injury.

*Conclusions: Inhibition of ferroptosis during donor liver cold preservation protected LSECs, resulting in alleviation of hepatic IR-stress after OLT. The beneficial effects of ferroptosis inhibition during warm IR resulted from hepatocyte cytoprotection. This study provides the basis for novel therapeutic strategies by targeting ferroptosis cell death during both, cold liver preservation and in OLT recipients.

« Back to 2021 American Transplant Congress