Clinical Implications of the Serum Apelin Level on Portal Hypertension and Prognosis of Liver Cirrhosis

BACKGROUND/AIMS Levels of serum apelin (s-apelin), an endogenous ligand for angiotensin-like receptor 1, have been shown to be related to hepatic fibrosis and hemodynamic abnormalities in preclinical studies. We investigated the clinical implications of s-apelin as a noninvasive prognostic biomarker for chronic liver disease (CLD). METHODS From January 2009 to December 2012, 215 CLD patients were enrolled and underwent clinical data collection, hepatic venous pressure gradient (HVPG) measurement, and liver biopsy. s-apelin was detected with a human total apelin enzyme-linked immunosorbent assay kit. All patients were prospectively observed during the median follow-up period of 23.0±12.9 months for decompensation and mortality. RESULTS A total of 42 patients (19.5%) died during the follow-up period. s-apelin was significantly correlated with measurements of liver stiffness (R2=0.263, p<0.001) and collagen proportional area (R2=0.213, p<0.001) measured from liver biopsy tissue and HVPG (R2=0.356, p<0.001). In a multivariate analysis using a Cox regression hazard model, s-apelin was a weakly significant predictor of decompensation (hazard ratio [HR], 1.002; p<0.001) and mortality (HR, 1.003; p<0.001). CONCLUSIONS s-apelin showed a significant relationship with CLD severity. However, its significance as a noninvasive biomarker for disease severity and prognosis was weak.