Hepatic stellate cells and the reversal of fibrosis.

Hepatic fibrosis is an outcome of many chronic liver diseases, such as viral and autoimmune hepatitis, and of alcohol consumption and biliary obstruction. Prolonged liver injury results in hepatocyte damage, which triggers activation of hepatic stellate cells (HSC) and recruitment of inflammatory cells into the liver. The HSC play a critical role in fibrogenesis. They produce collagen type I and secrete pro-fibrogenic cytokines and inhibitors of matrix-degrading enzymes (tissue inhibitor of matrix metalloproteinase), causing the production of extracellular matrix deposition over degradation. However, many clinical and experimental studies suggest that this process can be reversed, including the apoptosis of activated HSC. Thus, HSC represent an appealing target for antifibrotic therapy. This review will focus on some aspects of etiology and molecular pathogenesis of liver fibrosis and the reversal of fibrosis.