Brain-Derived Neurotrophic Factor in Airway Smooth Muscle: Contributions to Asthma

Bronchial airways are key elements of respiratory structure and function throughout life. Airway diseases such as asthma and chronic obstructive pulmonary disease arise from intrinsic factors such as fetal and neonatal developmental abnormalities, and importantly from lifelong exposures to allergens, inflammatory mediators, and environmental insults such as pollutants and tobacco smoke. Considering the fact that within airways, the airway smooth muscle (ASM) represents a major fraction of total area as well as mass, brain-derived neurotrophic factor (BDNF) produced by ASM could reach physiologically-relevant levels. ASM-derived BDNF has the potential for paracrine effects on a number of cell types. Certainly, airway nerves are important, given extensive innervation of the bronchi. Asthma is a chronic condition involving inflammation-driven changes to bronchial airway structure and function, represented by hyperresponsiveness to bronchoconstrictors, impaired bronchodilation, and a largely irreversible remodeling of the airway leading to obstruction.