Point:Counterpoint: Alterations in airway smooth muscle phenotype do/do not cause airway hyperresponsiveness in asthma

Summary. Airway hyperresponsiveness and obstruction are cardinal features of asthma. Compelling evidence now suggests that the key features of asthma in part are due to intrinsic differences in airway smooth muscle (ASM) function. Inflammatory mediators alter ASM phenotype, which directly modulates ASM hyperresponsiveness and promotes airway remodeling that further contributes to amplified airway obstruction. For decades, the most effective and common therapies in the management of asthma have focused on bronchodilation and reversal of ASM shortening. Accordingly, alterations in the phenotype of ASM, the pivotal cell regulating bronchomotor tone, fundamentally contribute to airway hyperresponsiveness in asthma.