Extracellular matrix microenvironment contributes actively to pulmonary fibrosis

PURPOSE OF REVIEW: The purpose of this review is to describe the contribution of an altered, profibrotic extracellular matrix (ECM) microenvironment to pulmonary fibrosis and how it changes cell behaviour and actively drives disease progression. RECENT FINDINGS: Idiopathic pulmonary fibrosis is a chronic and fatal disease of unknown cause. It is characterized by proliferation and accumulation of fibroblasts and myofibroblasts in clusters, termed fibroblastic foci, and extensive ECM deposition. Recent evidence from in-vivo and ex-vivo experimental studies has highlighted that the abnormal ECM in fibrotic lungs alters the behaviour of epithelial and mesenchymal cells. This profibrotic ECM microenvironment is characterized by altered biochemical and biomechanical properties and stores abundant amount of growth factors. By this, the 'fibrotic ECM' can drive progressive fibrogenesis in the lungs without any further initiating trigger. These concepts indicate a more complicated dynamic and active role of the fibrotic ECM than previously thought and offer many novel therapeutic targets. SUMMARY: The fibrotic ECM microenvironment is an active contributor to the development and progression of pulmonary fibrosis and a promising therapeutic target.