Rapid corticosteroid effect on β2-adrenergic airway and airway vascular reactivity in patients with mild asthma

BackgroundLong-term glucocorticoid therapy has been suggested to improve airway and airway vascular smooth muscle responsiveness to inhaled β2-agonists in patients with asthma.ObjectiveWe sought to assess whether a single dose of an inhaled glucocorticoid acutely potentiates β2-adrenergic airway and airway vascular smooth muscle reactivity in asthma.MethodsIn 10 asthmatic and 10 healthy subjects, airway blood flow and FEV1 were measured before and 30 minutes after fluticasone or placebo inhalation and 15 minutes after the subsequent inhalation of racemic albuterol (0.6 mg or 1.25 mg) or (R)-albuterol (0.3 mg or 0.6 mg).ResultsIn healthy subjects all albuterol formulations increased airway blood flow equally after placebo or fluticasone pretreatment. In asthmatic subjects airway blood flow response was blunted after placebo and acutely restored after fluticasone pretreatment. Fluticasone pretreatment did not increase FEV1 responses to any albuterol formulation, except 0.6 mg racemic albuterol.ConclusionA single dose of an inhaled glucocorticoid restores β2-adrenergic airway vasodilator responses in patients with mild asthma. The mechanism of this rapid glucocorticoid effect remains to be clarified.