Fig. 1.

Overview of fibrosis. Fibrosis is triggered by an insult such as damage to the endothelial cells in the vasculature. These damaged endothelial cells secrete cytokines resulting in the recruitment of immune cells. Immune cells produce transforming growth factor (TGF)-beta1, connective tissue growth factor (CTGF), and platelet-derived growth factor (PDGF) leading to fibroblast activation, proliferation and differentiation into myofibroblasts. The downstream effect is excessive extracellular matrix (ECM) synthesis and deposition by fibroblasts and myofibroblasts, a hallmark feature of fibrosis.

IL, interleukin; TNF, tumor necrosis factor.