Non-invasive prediction of NAFLD severity: a comprehensive, independent validation of previously postulate serum microRNA biomarkers

Liver biopsy is currently the only reliable method to establish non-alcoholic fatty liver disease (NAFLD) severity. However, this technique is invasive and occasionally associated with severe complications. Thus, non-invasive diagnostic markers for NAFLD are needed. Former studies have postulated 18 different serum biomarker microRNAs with altered levels in NAFLD patients. In this study, we have re-examined the predictive value of these serum microRNAs and found that only 6 of them (miR-34a, -192, -27b, -122, -197 and -30c) are validated in our independent cohort as biomarkers associated with NAFLD severity. Among them, miR-192, -27b and -122 are abundantly expressed in liver and confidently detected in serum, and display strong correlations with transaminases. The classification performance of validated miRNAs (and their ratios) for patients with non-alcoholic steatohepatitis (NASH) is similar to that reached by AST, whereas for advanced fibrosis prediction, the miR-27b/-197 ratio demonstrated a good performance and an excellent sensitivity and, along with the FIB-4 index, may constitute a potent non-invasive predictive tool. Overall design: 8 patients classified in SAF1 and SAF2 groups. SAF1 as control and SAF2 as case