Liver fibrosis and hepatic stellate cells

Chronic hepatic inflammation leads to fibrosis. Hepatic stellate cells are activated in liver injury, playing a central role in the fibrogenesis under the influence of key cytokines. Transforming growth factor-β and platelet derived growth factor enhance matrix production and proliferation of stellate cells, respectively, and thereby accelerating fibrogenesis. Tumor necrosis factor-α, a major inflammatory cytokine, suppresses matrix production. Endothelin-1 exerts a strong contractile stimulus to stellate cells and may regulate sinusoidal blood flow. Retinoids are released during activation of stellate cells, yet they exert varying effects depending upon their molecular structure. Recent advances in understanding cellular and molecular mechanisms of liver fibrosis will lead to the development of new therapy of the fibrosis.