Hepatic stellate cells express all components of the renin-angiotensinogen (AGT) system and secrete active angiotensin II. Animal studies provided evidence that angiotensin II stimulates the accumulation of extracellular matrix by enhancing transforming growth factor beta1 production. A functional genetic alteration in the human AGT promoter (c.1-44G>A) has been linked to accelerated progression of fibrosis in hepatitis C virus infection.