Inflammatory basis of exercise-induced bronchoconstriction.
BACKGROUND
Exercise-induced bronchoconstriction (EIB) is a highly prevalent condition with unclear pathogenesis. Two competing theories of the pathogenesis of EIB differ regarding the inflammatory basis of this condition.


OBJECTIVE
Our goals were to establish whether epithelial cell and mast cell activation with release of inflammatory mediators occurs during EIB and how histamine and cysteinyl leukotriene antagonists alter the airway events occurring during EIB.


METHODS
Induced sputum was used to measure mast cell mediators and eicosanoids at baseline and 30 minutes after exercise challenge in 25 individuals with asthma with EIB. In a randomized, double-blind crossover study, the cysteinyl leukotriene antagonist montelukast and antihistamine loratadine or two matched placebos were administered for two doses before exercise challenge.


RESULTS
The percentage of columnar epithelial cells in induced sputum at baseline was associated with the severity of EIB. After exercise challenge, histamine, tryptase, and cysteinyl leukotrienes significantly increased and prostaglandin E(2) and thromboxane B(2) significantly decreased in the airways, and there was an increase in columnar epithelial cells in the airways. The concentration of columnar epithelial cells was associated with the levels of histamine and cysteinyl leukotrienes in the airways. Treatment with montelukast and loratadine inhibited the release of cysteinyl leukotrienes and histamine into the airways, but did not inhibit the release of columnar epithelial cells into the airways.


CONCLUSIONS
These data indicate that epithelial cells, mast cell mediators, and eicosanoids are released into the airways during EIB, supporting an inflammatory basis for EIB.
Hallstrand
Teal S
TS
Department of Medicine, Division of Pulmonary and Critical Care, University of Washington, Seattle, Washington 98195-6522, USA. tealh@u.washington.edu
Moody
Mark W
MW
Wurfel
Mark M
MM
Schwartz
Lawrence B
LB
Henderson
William R
WR
Aitken
Moira L
ML
D000085:Acetates / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D001991:Bronchitis / Q000209:etiology* / Q000503:physiopathology*; D016084:Bronchoconstriction; D018592:Cross-Over Studies; D003521:Cyclopropanes; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D005541:Forced Expiratory Volume; D039563:Histamine H1 Antagonists, Non-Sedating / Q000627:therapeutic use; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D020024:Leukotriene Antagonists / Q000627:therapeutic use; D017336:Loratadine / Q000627:therapeutic use; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011804:Quinolines / Q000627:therapeutic use; D012720:Severity of Illness Index; D013440:Sulfides
D000085:Acetates; D003521:Cyclopropanes; D039563:Histamine H1 Antagonists, Non-Sedating; D018836:Inflammation Mediators; D020024:Leukotriene Antagonists; D011804:Quinolines; D013440:Sulfides; D017336:Loratadine; C093875:montelukast