Role of macrophages in liver cirrhosis: fibrogenesis and resolution.

At present, chronic liver disease accounts for approximately 2 million deaths per year worldwide. Liver injury induces a series of events causing inflammation. Chronic inflammation ends in liver fibrosis. A stage of fibrinolysis occurs on stopping insult. Kupffer cells play their role to initiate inflammatory responses, while infiltrating monocyte-derived macrophages have a role both in chronic inflammation and fibrosis and in fibrosis resolution. Ly-6C high expressing monocytes act during fibrogenesis, while Ly-6C low expressing monocytes are restorative macrophages which promote resolution of fibrosis after end of the injury. Recent studies have identified new phenotypes, such as metabolically activated M, oxidized, which may have a role in fatty liver diseases.