The effects of current therapies on airway remodeling in asthma and new possibilities for treatment and prevention

Airway inflammation, airway remodeling and airway hyperresponsiveness are the fundamental components of pathogenesis that lead to symptoms and lung function changes in asthma. Airway remodeling describes the structural changes to the airways in asthma. The remodeling process involves diverse pathological changes including epithelial metaplasia, subepithelial fibrosis, angiogenesis and smooth muscle thickening. Airway remodeling contributes to irreversible loss of lung function and airway hyperresponsiveness. Remodeling is associated with severe and persistent disease but can also occur early in the course of disease pathogenesis and does not resolve spontaneously. Current asthma therapies, for example corticosteroids, are successful in treating allergic inflammation, an important factor contributing to remodeling, but do not specifically target the remodeling process, and remodeling changes progress despite optimal control of inflammation. Moreover, airway remodeling is not eradicated or prevented despite widespread use of anti-inflammatory treatments. There is limited evidence for the effectiveness of leukotriene inhibitors, phosphodiesterase inhibitors, mast cell tryptase inhibitors, and peroxisome proliferator-activated receptor gamma agonists in the treatment or prevention of remodeling changes. The search for novel therapies that can specifically reverse or prevent airway remodeling is an active area of research. Treatments that may be useful in preventing airway remodeling include those that directly or indirectly target single or multiple components of the airway remodeling process. Identification of novel asthma genes may also allow disease targeting. A better understanding of airway remodeling in asthma will facilitate the development of new treatments for asthma beyond control of symptoms and inflammation.