Analysis of Serum MicroRNA-122 Expression at Different Stages of Chronic Hepatitis B Virus Infection

Objective. To investigate the expression of microRNA-122 (miR-122) in the progression of chronic hepatitis B virus- (HBV-) infected liver diseases, thus determining the role of serum miR-122 as a marker of HBV-caused liver injury. Methods. Sera were collected from patients with different stages of HBV infection (n=63) and healthy volunteers (n=11). And the serum miR-122 levels were detected using RT-qPCR. Moreover, an analysis was applied for identifying the specific correlation of the miR-122 level with HBV DNA, HBeAg, and ALT levels. After liver biopsy, Ishak scoring was utilized for evaluation of the fibrosis stage and the histological activity index (HAI). Results. We confirmed, in the serum, increased miR-122 expression in HBV-infected patients and its highest expression in chronic HBV carriers, based on such comparison between the healthy controls and patients. The correlation analysis results were taken as confirmation of the positive relationship of miR-122 with HBV DNA (r=0.354, P=0.005) and ALT (r=0.331, P=0.009). But no correlation of this molecule with HBeAg levels was found (P=0.187). In comparison with the HBeAg-negative patients, serum miR-122 expression showed an increase in the HBeAg-positive patients (P=0.001). miR-122 expression, in addition, was of a significant correlation with HAI, but not with the liver fibrosis score. Conclusion. The peak of the serum miR-122 expression normally occurs in the early stage of the progression from the HBV carrier phase to chronic hepatitis to cirrhosis. This molecule can be considered as a marker for evaluation of HBV-caused liver injury.