Alpha-smooth-muscle actin expression in normal and fibrotic human livers.

To determine the significance of the expression of alpha-smooth-muscle actin in the fibrotic human liver, normal and diseased livers were stained with anti-alpha-smooth-muscle-actin antibody by an immunoperoxidase method. Vitamin A-containing lipocytes were also identified by the modified Kupffer's gold chloride method. In the normal human liver, lipocytes as well as vascular smooth muscle cells expressed alpha-smooth-muscle actin. In alcoholic liver disease, there was an increase in the cells positive for alpha-smooth-muscle actin adjacent to the fibrotic areas, but the response of lipocytes to the gold chloride reaction diminished. In chronic hepatitis, the cells positive for alpha-smooth-muscle actin increased around the enlarged portal areas, and the response to the gold chloride reaction did not change appreciably. An increase in the cells positive for alpha-smooth-muscle actin was associated with the progression of hepatic fibrosis in the liver of patients with alcoholic liver disease and chronic hepatitis.