title: New insights into pathogenesis of exercise-induced bronchoconstriction.
abstract: OBJECTIVE
  Exercise-induced bronchoconstriction (EIB) refers to acute airflow obstruction that is triggered by a period of physical exertion. Here we review recent findings about the epidemiology of EIB, immunopathology leading to EIB, and the latest understanding of the pathogenesis of EIB.
  
  
  RESULTS
  Longitudinal studies demonstrated that airway hyper-responsiveness to exercise or cold air at an early age are among the strongest predictors of persistent asthma. Patients that are susceptible to EIB have epithelial disruption and increased levels of inflammatory eicosanoids such as cysteinyl leukotrienes (CysLT)s. The leukocytes implicated in production of eicosanoids in the airways include both a unique mast cell population as well as eosinophils. A secreted phospholipase A(2) (sPLA(2)) enzyme that serves as a regulator of CysLT formation is present in increased quantities in asthma. Transglutaminase 2 (TGM2) is expressed at increased levels in asthma and serves as a regulator of secreted phospholipase A(2) group X (sPLA(2)-X). Further, sPLA(2)-X acts on target cells such as eosinophils to initiate cellular eicosanoid synthesis.
  
  
  CONCLUSIONS
  Recent studies have advanced our understanding of EIB as a syndrome that is caused by the increased production of inflammatory eicosanoids. The airway epithelium may be an important regulator of the production of inflammatory eicosanoids by leukocytes.
authors.affiliation: Department of Medicine, Division of Pulmonary and Critical Care, University of Washington, Seattle, Washington 98195, USA. tealh@uw.edu
authors.forename: Teal S
authors.initials: TS
authors.lastname: Hallstrand
mesh_terms: D001250:Asthma, Exercise-Induced / Q000201:enzymology / Q000276:immunology*; D016535:Bronchial Hyperreactivity / Q000201:enzymology / Q000276:immunology*; D003545:Cysteine / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology*; D006801:Humans; D015289:Leukotrienes / Q000276:immunology*; D008137:Longitudinal Studies; D054467:Phospholipases A2 / Q000276:immunology*
chemical_list: D015289:Leukotrienes; C112381:cysteinyl-leukotriene; D054467:Phospholipases A2; D003545:Cysteine