Mechanism of action and clinical significance of lipoprotein X in cholestatic liver disease

Lipoprotein X （LpX） is an atypical lipoprotein that abnormally accumulates in the plasma of patients with cholestatic liver disease， and it is also a major pathogenic factor for hypercholesterolemia. The formation of LpX is closely associated with the abnormal metabolism of free cholesterol， phospholipids， and other lipid components in bile. LpX cannot be cleared via the low-density lipoprotein receptor pathway and is mainly metabolized by the reticuloendothelial system. The abnormal accumulation of LpX is closely associated with various complications of cholestatic liver disease， including xanthoma and neuropathy. Although there is no significant correlation between the high level of LpX and the risk of atherosclerosis， the role of LpX in cholesterol metabolism disorders cannot be neglected. Due to the similarities in density and characteristics between LpX and low-density lipoprotein cholesterol， clinical testing may result in misdiagnosis and related treatment risks. Current studies mainly focus on the mechanisms of LpX formation， the clinical significance of LpX， related detection methods， and potential therapeutic strategies. Plasma exchange is considered the preferred treatment in the state of high LpX， while traditional lipid-lowering drugs have a limited effect on LpX. This article explores the formation and clearance mechanisms of LpX in cholestatic liver disease， along with its impact of cholestatic liver disease and related detection methods， in order to improve the understanding of the pathophysiology and clinical significance of LpX， provide new strategies for the management of cholestatic liver disease and its complications， and finally improve the prognosis of patients.