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

Abstract

OBJECTIVE:: To investigate the roles and underlying mechanism of an inflammatory mediator-lipocalin-2 (Lcn2) in small-for-size fatty graft liver injury. BACKGROUND:: 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). METHODS:: 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. RESULTS:: 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. CONCLUSIONS:: 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.