Figure 2

Mechanisms perpetuating pulmonary fibrosis. Pathogenesis of pulmonary fibrosis is initiated by microvascular injury, which leads to endothelial cell damage and alveolar epithelial injury. This leads to activation of the coagulation cascade, release of various cytokines and growth factors, and ultimately activation of fibroblasts, a key event in the development of fibrosis. CTGF, connective tissue growth factor; IGF-1, insulin-like growth factor-1; LPA, lysophosphatidic acid; TGF-β, transforming growth factor beta.