(a) Supportive and (b) inflammatory interactions between hepatocytes and nonparenchymal cells in the liver. Abbreviations: ECGF, endothelial cell growth factor; EGF, epidermal growth factor; HGF, hepatocyte growth factor; ICAM, intercellular adhesion molecule; IL, interleukin; LPS, lipopolysaccharide; RNI, reactive nitrogen intermediates; ROS, reactive oxygen species; TGF, transforming growth factor; TNF, tumor necrosis factor; VCAM, vascular cell adhesion molecule; VEGF, vascular endothelial growth factor.