[Cytokines in the pathogenesis of liver fibrosis]

Cytokines are synthetized and secreted in the liver mostly by Kupffer cells and play a key role in inflammatory processes and immunological response related to liver diseases, which are initiated by hepatocytes damage. This type of signalling between different types of liver cells, can produce contrary reactions. For instance transforming growth factors beta as well as inetrleukins 1 beta, 4 and 6 induce fibrosis. In contrast, transforming growth factor alpha, tumor necrosis factor alpha, interleukins 1 alpha and interferons are inhibitory to fibrosis. Lost of the balance between these stimuli seems to be responsible for activation of nonparenchymal cells, that result in accumulation of extracellular matrix proteins (including collagens) with liver cirrhosis as a clinical effect. Connections between cytokines, cells located in the liver and diseases with hepatic fibrosis are reviewed in this article.