Activation of epithelial and inflammatory pathways in adolescent elite athletes exposed to intense exercise and air pollution

RationaleParticipation in high-intensity exercise in early life might act as stressor to the airway barrier.ObjectivesTo investigate the effect of intense exercise and associated exposure to air pollution on the airway barrier in adolescent elite athletes compared with healthy controls and to study exercise-induced bronchoconstriction (EIB) in this population.MethodsEarly-career elite athletes attending ‘Flemish-Elite-Sports-Schools’ (12–18 years) of 4 different sport disciplines (n=90) and control subjects (n=25) were recruited. Presence of EIB was tested by the eucapnic voluntary hyperventilation (EVH) test. Markers at mRNA and protein level; RNA-sequencing; carbon load in airway macrophages were studied on induced sputum samples.Results444 genes were differentially expressed in sputum from athletes compared with controls, which were related to inflammation and epithelial cell damage and sputum samples of athletes contained significantly more carbon loaded airway macrophages compared with controls (24%, 95% CI 20% to 36%, p10and PM2.5exposure.ConclusionEarly-career elite athletes showed increased markers of air pollution exposure, epithelial damage and airway inflammation compared with controls. Acute exposure to increased air pollution PM10levels was linked to increased airway hyper-reactivity.Trial registration numberNCT03587675.