Evaluation of miR-122 Serum Level and IFN-λ3 Genotypes in Patients with Chronic HCV and HCV-Infected Liver Transplant Candidate.

Background: Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are the most common markers of liver damage, but serum level interpretation can be complicated. In hepatocytes, microRNA-122 (miR-122) is the most abundant miRs and its high expression in the serum is a characteristic of liver disease.

Objective: We aimed to compare the circulatory level of miR-122 in patients with Chronic Hepatitis C (CHC), Hepatitis C Virus (HCV) infected Liver Transplant Candidates (LTC) and healthy controls to determine if miR-122 can be considered as an indicator of chronic and advanced stage of liver disease.

Methods: MiR-122 serum level was measured in 170 Interferon-naïve (IFN-naïve) CHC patients, 62 LTC patients, and 132 healthy individuals via TaqMan real-time PCR. Serum levels of miR-122 were normalized to the serum level of Let-7a and miR-221. Also, the ALT and AST levels were measured.

Results: ALT and AST activities and the expression of circulatory miR-122 were similar in the CHC and LTC groups, but it had significantly increased compared to healthy individuals (P<0.001 and P<0.001, respectively). Up-regulation of miR-122 in the sample of patients with normal ALT and AST activities was also observed, indicating that miR-122 is a good marker with high sensitivity and specificity for diagnosing liver damage.

Conclusion: miR-122 seemed to be more specific for liver diseases in comparison with the routine ALT and AST liver enzymes. Since the lower levels of circulating miR-122 were observed in the LTC group compared to the CHC group, advanced liver damages might reduce the release of miR-122 from the hepatocytes, as a sign of liver function deficiency.