Original ContributionsQuantitative analysis of liver fibrosis and stellate cell changes in patients with chronic hepatitis C after interferon therapy

Objective: The proliferation and differentiation of stellate (Ito, or fat-storing) cells into myofibroblast-like cells is responsible for the development of liver fibrosis. Using computer image analysis, we evaluated the changes of α smooth muscle actin–positive stellate cells and liver fibrosis after interferon-α or -β (IFN-α, β) therapy in patients with chronic hepatitis C. Methods: Patients with chronic hepatitis C were treated with IFN-α or -β and were divided into three groups on the basis of clinical criteria; a complete responder group (CR, 18 of 51), a partial responder group (PR, 17 to 51), and a nonresponder group (NR, 16 of 51). Liver fibrosis was assessed from specimens stained with Sirius red and was quantitated by computer image analysis. We also evaluated α-smooth muscle actin expression in the liver before and after IFN therapy by a semiquantitative scoring method (the α-smooth muscle actin index). Results: Before IFN therapy, a large number of stellate cells expressing α-smooth muscle actin were present in the liver biopsy specimens. There was a significant correlation (r = 0.699, p < 0.05) between the change in the percent area of fibrosis and the α-smooth muscle actin index before and after IFN therapy in all groups. The complete responder group also showed a significant reduction of α-smooth muscle actin-expressing cells that was correlated with the reduction of serum ALT (r = 0.686, p < 0.05). Conclusion: These results suggest α-smooth muscle actin-expressing cells are responsible for liver fibrosis, and the elimination of factors stimulating matrix synthesis (e.g., hepatitis virus) may decrease liver fibrosis.