Nonalcoholic fatty liver disease. Correlation with histology and viral hepatitis

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) involves a heterogeneous group of diseases that places some patients at risk of progression to cirrhosis. In this study, our aim was to investigate the relationships between the histopathological features of NAFLD, hepatic stellate cell activation, and capillarization to find a marker related to fibrosis, for NAFLD.

METHODS: We studied liver biopsies from 62 patients with NAFLD, 21 patients with hepatitis B, and 19 patients with hepatitis C from the archives of the Department of Pathology, Gazi University Medical School, between 1997 and 2004. We performed immunoperoxidase stains for a-smooth muscle actin (a-SMA) and CD31 to identify activated hepatic stellate cells and capillarization. We investigated the relationships between histopathological features and both a-SMA and CD31 expressions.

RESULTS: Most NAFLD cases were in low grades and stages. We found a relationship between both necroinflammatory grade and ballooning degeneration, and fibrosis. Pure steatosis did not relate to fibrosis. Immunohistochemical analysis revealed that CD31 expression was significantly higher than a-SMA expression in all groups. We determined a correlation between the fibrotic stage and CD31 expression, but not with a-SMA expression. In NAFLD cases, we detected the highest staining scores of CD31 in zone 3, while the portal/septal area was the dominant zone for control groups. There was no significant zone for a-SMA expression.

CONCLUSION: Our results suggest that we can use CD31, rather than a-SMA, as a marker of endothelial damage and sinusoidal capillary transformation, both of which might precede fibrogenesis in chronic liver diseases, particularly in NAFLD.