Purpose: The aim of this study was to assess whether a single high dose of beclomethasone dipropionate (BDP) could blunt mast cell activation and bronchoconstriction after eucapnic voluntary hyperpnea (EVH).
Methods: In this model of exercise-induced bronchoconstriction (EIB), seven athletes with EIB and eight untrained subjects with mild asthma performed two EVH tests 5.5 h apart on the same day; the first challenge after inhalation of a placebo aerosol and the second 4 h after inhalation of BDP (1500 microg). Prechallenge and postchallenge pulmonary function and urinary excretion of the mast cell mediator 9alpha, 11beta-prostaglandin (PG) F2 were followed, as well as urinary excretion of the bronchoconstrictor leukotriene (LT) E4.
Results: The EVH-induced bronchoconstriction was inhibited by BDP in both groups (P < 0.001): in athletes, mean +/- SEM percent fall in forced expiratory volume in 1 s was 22% +/- 4% after placebo versus 13% +/- 3% after BDP; in subjects with asthma, 23% +/- 4% after placebo versus 14 +/- 3% after BDP. This inhibition of airway response was associated with a significant reduction in the urinary excretion of 9alpha,11beta-PGF2 (P = 0.039) and LTE4 (P = 0.003) in both groups. Significant correlations were found between the percent fall in forced expiratory volume in 1 s and the increase in urinary excretion of both mediators 9alpha,11beta-PGF2 (r = 0.544, P = 0.002) and LTE4 (r = 0.380, P = 0.038) after EVH.
Conclusions: We conclude that a single dose of BDP has an acute protective effect on the bronchial response to hyperpnea in both untrained subjects with asthma and athletes with EIB. This effect was associated with decreased excretion of urinary mediators, suggesting that BDP blunted the mast cell activation.