airway wall remodelling
airway wall remodellingA series of structural changes seen in the airways of patients with severe asthma, including interstitial fibrosis and reduced responsiveness to therapy.
Components Hypertrophy and hyperplasia of airway smooth muscle, myofibroblast activation (increased subepithelial basement membrane collagen deposition), angiogenesis (increased submucosal blood vessels), and increased airway epithelial goblet cells. The increased smooth-muscle mass and thickened subepithelial basement membrane are controlled by a complex interaction between mesenchymal growth factors (TGF, EGF, IGF) and their receptors and the balance between degradative enzymes (e.g., the matrix metalloproteinase, MMP-9, and its inhibitor, TIMP-1); tissue remodelling, as demonstrated by collagen deposition and expansion of the smooth-muscle mass, may be driven by an imbalance in this delicately controlled system. Tissue remodelling may also involve increased neural innervation, and nerve growth factor has been implicated in upregulating neuropeptides (substance P and calcitonin gene-related peptide) in the primary sensory neurones innervating inflamed tissues.