Airway inflammation and remodelling changes in patients with chronic cough: do they tell us about the cause of cough?

Abstract

Airway mucosal changes have been reported in chronic cough. In cough variant asthma and in eosinophilic bronchitis, there is evidence of eosinophil infiltration and sub-basement membrane thickening. In non-asthmatic cough, an increase of bronchoalveolar mast cells, mucosal mononuclear cells, and epithelial shedding have been reported. In a more recent study, evidence of airway wall remodelling has been observed in both asthmatic and non-asthmatic cough, such as an increase in sub-basement membrane thickness, goblet cell area, vascularity and vessel size. Smooth muscle area was increased in non-asthmatic coughers. Heightened cough sensitivity in non-asthmatic coughers was related to the degree of goblet cell hyperplasia and epithelial shedding. Cough reflex may be heightened by increased production of growth factors that might be further enhanced by the physical effects of cough on the airways. Mast cells may participate in the cough pathophysiology through release of growth factors as well as tussive mediators. Changes in the airway wall mucosa and epithelium may be important in the pathogenesis of cough receptor sensitization.