Figure 1.

Abnormal wound-healing model of idiopathic pulmonary fibrosis pathogenesis. In the model proposed by Selman et al. [10], microinjuries damage the epithelium and cause the release of profibrogenic growth factors and the development of an antifibrinolytic microenvironment that promotes wound clot formation. Proliferating and differentiating fibroblasts migrate through a disrupted basement membrane, secreting extracellular matrix (ECM) proteins and angiogenic factors. An imbalance in matrix-degrading and matrix-enhancing enzymes favours increased deposition of ECM. Myofibroblasts are not removed and they release growth factors that promote epithelial cell apoptosis.