The Roles of Lipocalin-2 in Small-for-Size Fatty Liver Graft Injury

Abstract

To investigate the roles and underlying mechanism of an inflammatory mediator-lipocalin-2 (Lcn2) in small-for-size fatty graft liver injury. Understanding of the distinct mechanism regulating small-for-size fatty liver graft injury will be crucial to prevent marginal graft failure during living donor liver transplantation (LDLT). The roles of Lcn2 in small fatty graft injury were investigated in orthotopic liver transplantation model rats, human LDLT samples, an in vitro simulated ischemia-reperfusion (IR) model, and a hepatic ischemic reperfusion plus major hepatectomy (IR + H) model in mice. Our result showed that Lcn2 was significantly upregulated together with elevation of chemokine (C-X-C motif) ligand 10 (CXCL10) and activation/infiltration of intragraft macrophages after liver transplantation using small-for-size fatty liver graft compared with that of using small-for-size normal liver graft. Intragraft and plasma levels of Lcn2 were intensified in patients who underwent transplantation with small-for-size fatty graft after LDLT. Lcn2 and CXCL10 were expressed higher in fatty hepatocytes after the simulated IR injury compared with normal hepatocytes. Overexpression of Lcn2 significantly deteriorated IR + H-induced hepatic injury in correlation with upregulation of CXCL10 and augmentation of infiltrated macrophages. On the contrary, hepatic injury of small fatty liver remnant after IR + H operation was attenuated in the Lcn-2 mice because of suppression of CXCL10 expression and diminishment of macrophage infiltration. Lcn2 is an important regulator in small-for-size fatty liver graft injury and targeting Lcn2 may be feasible for preventing marginal graft failure in LDLT.