PERCEPTION OF BRONCHIAL OBSTRUCTION IN ASTHMATIC-PATIENTS - RELATIONSHIP WITH BRONCHIAL EOSINOPHILIC INFLAMMATION AND EPITHELIAL DAMAGE ANDEFFECT OF CORTICOSTEROID TREATMENT

We studied the perception of bronchoconstriction in asthmatic subjects who were randomly treated with inhaled pt agonist given either alone (n = 9) or associated with inhaled corticosteroids (n = 9). Methacholi ne and bradykinin challenges, bronchoalveolar lavage, and bronchial bi opsies were performed in all subjects. After each dose of agonist, bre athlessness was assessed using a visual analog scale (VAS) and the for ced expiratory volume in 1 s (FEV(1)) was measured. The relationship b etween VAS scores and FEV(1) and the slope of the regression line of V AS scores on the corresponding FEV(1) (VAS/FEV(1) slope) were analyzed for each agonist. Subjects without corticosteroids had good perceptio n of methacholine but poor perception of bradykinin-induced bronchocon striction. In subjects with corticosteroids, bronchoconstriction was w ell perceived whatever the agonist. VAS/FEV(1) slopes for bradgkinin b ut not for methacholine correlated negatively with the magnitude of eo sinophilic inflammation in airway mucosa. VAS/FEV(1) slopes for each a gonist correlated positively with the percentage of basement membrane covered by airway epithelium. We conclude that in asthmatic patients p erception of bronchoconstriction is related to eosinophilic inflammati on and to epithelial damage in airways and that corticosteroid treatme nt is associated with improved perception of bronchoconstriction induc ed by bradykinin, a mediator endogenously produced in asthma.