Published online Nov 7, 2014. doi: 10.3748/wjg.v20.i41.15343
Revised: May 7, 2014
Accepted: June 13, 2014
Published online: November 7, 2014
AIM: To assess the expression of selected microRNAs (miRNA) in hepatitis C, steatotic hepatitis C, noninfected steatotic and normal liver tissues.
METHODS: The relative expression levels of miR-21, miR-33a, miR-96, miR-122, miR-125b, miR-221 and miR-224 were determined in 76 RNA samples isolated from 18 non-steatotic and 28 steatotic chronic hepatitis C (CHC and CHC-Steatosis, respectively) cases, 18 non-infected, steatotic liver biopsies of metabolic origin (Steatosis) and 12 normal formalin-fixed paraffin-embedded liver tissues using TaqMan MicroRNA Assays. All CHC biopsy samples were obtained prior to initiating therapy. Patients’ serum biochemical values, which included glucose, triglyceride, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl-transferase (GGT), alkaline phosphatase (AP), were obtained and correlated with relative miRNA expression.
RESULTS: When compared with control non-infected liver samples, miR-122 and miR-221 levels were reduced in CHC-Steatosis (P < 0.03) and in CHC, CHC-Steatosis and Steatosis (P < 0.01). Alternatively, the expression of miR-33a and miR-224 were elevated in CHC-Steatosis and Steatosis in comparison to control tissue (P < 0.01). The levels of miR-33a and miR-224 in CHC-Steatosis (P < 0.02) and miR-224 in Steatosis (P < 0.001) were increased in comparison to CHC samples. By contrast, the expression of miR-21 did not differ statistically between diseased and normal liver samples. Levels of miR-33a correlated negatively with serum AST and AP levels in Steatosis as well as with necroinflammatory grade in CHC, whereas miR-21 correlated positively with AST in Steatosis and displayed negative correlation with triglyceride level in CHC-Steatosis. In contrast, miRNA levels were not correlated with ALT, GGT, cholesterol levels or fibrosis stage.
CONCLUSION: Differences in miRNA expression were observed between CHC and steatotic CHC, CHC and steatotic liver, but not between steatotic CHC and steatotic liver of metabolic origin.
Core tip: Chronic hepatitis C (CHC) and steatosis are liver diseases that can progress into hepatocellular carcinoma. In the current study, differences were found in expression of selected microRNAs in biopsy samples of steatotic liver, CHC-infected, and steatotic CHC-infected liver, compared to control samples. Interestingly, levels of miR-224, which are increased in hepatocellular carcinoma, were elevated in both types of steatotic liver when compared with normal or CHC-infected only liver tissues, and may be an indicator of a precancerous state.