Airway remodeling in asthma.

Airway remodeling is a summary term for the pathological changes that occur in airway structure in allergic or suppurative airway diseases. Characteristic changes of airway remodeling in asthma include goblet cell hyperplasia, deposition of collagens in the basement membrane zone, increased size and number of microvessels in the submucosa, hyperplasia and hypertrophy of airway smooth muscle, and hypertrophy of submucosal glands. Some of these changes, such as goblet cell hyperplasia and subepithelial collagen deposition, are present even in mild asthma; other changes such as increases in airway smooth muscle and gland volume appear to be more characteristic of severe asthma. Airway narrowing, airway hyperresponsiveness, and mucus hypersecretion are all functional consequences of airway remodeling leading to clinical manifestations such as dyspnea, wheeze, sputum production, and susceptibility to asthma exacerbations. Noninvasive measures of remodeling are lacking, and monitoring the effects of treatment on remodeling has been difficult. For this reason relatively little is known about the effects of current asthma treatments on airway remodeling. As mechanisms of airway remodeling are developed, it is hoped that novel therapeutic targets will be identified. Treatments specifically targeting mediators of remodeling hold promise as treatments that could modify disease progression in asthma.