Substantial data have demonstrated that air pollution is associated with cardiopulmonary mortality and morbidity in the world. Among a variety of pollutants, particulate components, particularly PM2.5, are especially suggested to be harmful to our lung health. Diesel exhaust particles (DEPs) are the major component of PM2.5, and therefore the relationship between PM2.5 or PM10 and airway inflammatory responses of asthmatic and people of not-yet asthma onset is important to be investigated. Recent findings suggested that susceptibility to DEPs is dependent upon certain genetic variations of anti-oxidative stress enzymes such as GSTP1, which is largely regulated by a transcription factor Nrf2. By preliminary experiments, we found that exhaled breath condensates (EBC) are safely and repeatedly obtained from both disease and health persons, and that several biomarkers including growth factors, cytokines and oxidant stress markers could be measured.
In the present study, we attempted to study the airway inflammatory/fibrogenic responses from patients with asthma, and further, those from people who have suggestive, but not yet definite symptoms of asthma. Participants are asked to present exhaled breath condensates (EBC) by R-tubes during spontaneous breathing for 5 minutes, which are processed to measure several inflammatory/fibrogenic markers.
These molecules, including vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), basic fibroblast growth factor (FGF), IL-1 receptor antagonist, IL-8 and epidermal growth factor (EGF) tended to be increased in asthmatic group. These markers were significantly increased in severity step 4 patients as compared to mild asthmatics. There was a significant correlation between the PM10 concentration 1 month before the sampling of EBC and EBC EGF concentration. NO2 concentration and several markers in EBC in patients with asthma correlated with each other. EBC pH showed a significant relationship with the distance from main traffic roads.
These results suggested that mass screening using simple methods such as EBC and appropriate biomarkers might facilitate the progress in the prophylaxis against hazardous health effects of DE exposures in subjects with high susceptibility to DEPs.