Airway wall remodeling in asthma: from the epithelial layer to the adventitia.

Asthma is an episodic respiratory syndrome caused by several pathogenic processes. This recurrent syndrome is associated with an accelerated decline in lung function and increase in airway obstruction over time. The reduced lung function is a consequence of tissue restructuring of all the components of the airway wall: 1) epithelium metaplasia; 2) altered quantity, composition, and distribution of extracellular matrix components; 3) microvascular remodeling; and 4) increase of airway smooth muscle mass. How these structural changes affect lung functions is not entirely clear. Deeper understandings of the altered structure and related functional impairment are important for gaining insights into the mechanisms underlying asthma. This review describes the tissue remodeling observed in different compartments of the asthmatic airway wall, from the airway lumen to adventitia. The underlying mechanisms driving the remodeling processes are also briefly reviewed.