Beclomethasone dipropionate attenuates airways hyperresponsiveness to neurokinin A and histamine in asthma

SummaryBackgroundInhaled corticosteroids (ICS) are the most effective anti-inflammatory agents available for the treatment of asthma but they produce only modest effects on airway inflammation and non-specific bronchial hyperresponsiveness (BHR). However, little is known about the possibility that treatment with ICS might cause additional protection on BHR to inhaled tachykinins such as neurokinin A (NKA).ObjectiveTherefore, we compared the effects of beclomethasone dipropionate (BDP) on the degree of BHR to inhaled histamine and NKA in a double-blind, controlled, cross-over study of asthmatic patients.MethodsPatients attended the laboratory before and after each 6 weeks treatment period to undertake concentration–response studies with histamine and NKA. Bronchial responsiveness to both funs was expressed as the provocative concentration producing a 20% decrease in FEV1 from baseline (PC20).ResultsBDP therapy attenuated the constrictor response to both agonists to a similar degree, their geometric mean (range) PC20 values increasing from 0.47 (0.21–1.41) mg/ml to 2.43 (0.51–4.50) mg/ml (P<0.01, post-salb vs. post-BDP treatment) and from 101.7 (27.3–356.1) μg/ml to 666.7 (151.5–1000) μg/ml (P<0.01, post-salb vs. post-BDP treatment) for histamine and NKA, respectively.ConclusionAirway responsiveness to histamine and NKA is reduced by BDP to the same extent. As a result of these findings, provocation with NKA is unlikely to provide additional useful information in the assessment of airway inflammation in asthma.