Liver fibrosis and inflammation. A review.

Hepatic fibrosis, is a wound healing process characterized by accumulation of extracellular matrix proteins (ECM) especially collagen types I and III, as well as an increase in other extracellular matrix constituents such as proteoglycans, fibronectin and laminin in response to liver injury. Recruitment of leukocytes takes place after the insult and requires several adhesion molecules. Monocytes and macrophages are involved in inflammatory actions by producing nitric oxide and inflammatory cytokines. As a consequence of chronic tissue damage stellate cells (SC) as well as extracellular matrix producting cells, undergo a process of activation characterized by proliferation, motility, contractility, and synthesis of extracellular matrix. Activation of SC is regulated by several soluble factors, including cytokines, chemokines, growth factors, and products of oxidative stress. TGF - b and IL- 6 are the two main fibrogenic cytokines. Potential regulatory factors of the activation of SC are important targets for future antifibrogenic treatments.