Effects of corticosteroids on structural cells in asthma and chronic obstructive pulmonary disease.

Structural cells such as airway smooth muscle, myofibroblasts, and fibroblasts play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease. Although considerable research effort has focused on the effects of steroids on leukocyte function and airway inflammation, few studies have investigated the effects of steroids on structural cell function. There is evidence that structural cells, apart from maintaining the integrity of the bronchial wall, may also participate in airway inflammatory responses. New data suggest that steroids inhibit some but not all proliferative and migratory responses in structural cells. Further, in structural cells the downstream signaling effects altered by glucocorticoids appear to differ from those observed in leukocytes. Therapeutic approaches designed to modulate chemokine and cytokine secretion by structural cells may offer new opportunities to treat diseases characterized by airway obstruction.