Serum and exosomal miR-122 and miR-199a as a biomarker to predict therapeutic efficacy of hepatitis C patients

MicroRNA (miRNA), which has been shown to correlate with liver functions, has been proposed as a new biomarker reflecting liver injury. The aim of the study was to investigate miRNA-122 (miR-122) and mir-RNA-199a (miR-199a) as a biomarker for predicting therapeutic efficacy in hepatitis C (HepC) patients. A total of 47 HepC 1b patients and 16 healthy subjects were enrolled in the study. Serum and exosomal mir-RNAs and other conventional biomarkers reflecting liver function were evaluated. The miR-122 levels in serum (miR-122(ser)) and exosomes (miR-122(exo)) were significantly lower in the Hepatitis C virus (HCV) genotype 1b patients than in the normal controls, but these levels were higher compared to the non-genotype 1b group. The mean miR-122(ser) level in the sustained virological response (SVR) group was significantly higher than that in the non-response (NR) group (P < 0.01), and the miR-122(exo) level in the SVR group was also higher than that in the NR group (P > 0.05), although this difference was not significant. miR-199a levels showed similar trends with the miR-122 levels in serum and exosomes. HCV RNA(ser) was negatively correlated with the miR-122(ser) (r = -0.473, P = 0.004) and miR-122(exo) (r = -0.424, P = 0.009) levels. miR-122(ser) levels were positively associated with miR-199a(ser) levels (r = 0.453, P = 0.002)(.) Univariate and multivariate regression analyses reveal that the miR-122(ser) levels and ALT/AST ratio demonstrated a predictive value in evaluating patient outcomes. Serum miR-122 and miR-199a are potential biomarkers that reflect therapeutic efficacy.