Differential expression of matrix metalloproteinases in viral and non-viral chronic liver diseases.

Background: Fibrosis is a common consequence of chronic liver diseases irrespective of aetiology. Metalloproteinases play an important role in the fibrotic process participating in the balance between collagen synthesis and degradation. We examined whether matrix gelatinases and stromelysins are similarly involved in the development of viral (HCV, HBV) and non-viral (NASH) liver diseases.

Methods: Hepatic mRNA levels of matrix metalloproteinase MMP-2, MMP-9, MMP-10 and MMP-11 isolated from liver biopsies were measured by semi-quantitative RT-PCR. Seventy-three patients were examined in this study: non-diseased controls (10), patients with chronic hepatitis B (14), chronic hepatitis C (33) and non-alcoholic steatohepatitis (16).

Results: A significant increase of MMP-9 and MMP-10 expression was found in patients with non-viral (non-alcoholic steatohepatitis) liver disease. Patients with chronic hepatitis B and hepatitis C showed an increase in MMP-2 mRNA expression compared to controls. Moreover, chronic hepatitis B and hepatitis C patients had significantly different mRNA expression patterns.

Conclusions: These findings indicate that matrix metalloproteinases are differentially involved in the fibrotic process of viral and non-viral chronic liver diseases. Differences exist between HBV and HCV chronic hepatitis. Differences between early and late fibrosis indicate that in future studies, careful staging of patients is mandatory for interpretation of results.