title: Biological monitoring of particulate matter accumulated in the lungs of urban asthmatic children in the Tel-Aviv area.
abstract: OBJECTIVE
  Lung inflammation from exposure to airborne particulate matter (PM) may be responsible for morbidity in asthma, but several studies using environmental monitoring data showed inconsistent results. Thus, the aim of this study was to evaluate the capability of induced sputum (IS) technology in order to biologically monitor PM in the lungs of urban asthmatic children.
  
  
  METHODS
  We collected clinical, demographic, biological and environmental monitoring data on 136 children referred for asthma evaluations. The study participants were divided into two groups according to IS eosinophil counts of <3% (non-eosinophilic inflammation, n = 52) and ≥3% (eosinophilic inflammation, n = 84).
  
  
  RESULTS
  The eosinophilic group displays significantly higher levels of fractional exhaled nitric oxide than the non-eosinophilic one (58.8 ± 47.5 vs 28.9 ± 34.2 ppm, p = 0.007). Particles (0-2.5 and 0-5 µm) comprised a strong risk factor for eosinophilic inflammation in IS (≥3%). Children with >80% of particles (0-2.5 µm) out of the total PM accumulated in the airways displayed the highest OR 10.7 (CI 2.052-56.4 p = 0.005) for an existing eosinophilic inflammation. Heme oxygenase-1 (HO-1) enzyme levels in IS positively correlated with % eosinophils and with particles in IS ranging between 2 and 3 μm. The level of HO-1 enzyme activity and FEV1/FVC in children with <3% eosinophils, but not ≥3%, was positively and significantly correlated, showing a protective effect of HO-1.
  
  
  CONCLUSIONS
  Accumulation of PM involves oxidative stress pathways and is a risk factor for developing eosinophilic inflammation in asthmatic children. IS can biologically monitor this process.
authors.affiliation: Laboratory of Pulmonary and Allergic Diseases, Tel-Aviv Sourasky Medical Center Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel, fireman@tlvmc.gov.il.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Fireman
authors.forename: Daria
authors.initials: D
authors.lastname: Bliznuk
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Schwarz
authors.forename: Ruth
authors.initials: R
authors.lastname: Soferman
authors.forename: Shmuel
authors.initials: S
authors.lastname: Kivity
mesh_terms: D000293:Adolescent; D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity; D001249:Asthma / Q000209:etiology*; D001944:Breath Tests; D002648:Child; D004784:Environmental Monitoring / Q000379:methods*; D004804:Eosinophils / Q000166:cytology; D005260:Female; D051547:Heme Oxygenase-1 / Q000276:immunology; D006801:Humans; D007501:Iron / Q000032:analysis; D007557:Israel; D007958:Leukocyte Count; D008168:Lung; D008297:Male; D009569:Nitric Oxide / Q000032:analysis; D009589:Nitrogen Oxides / Q000032:analysis; D018384:Oxidative Stress / Q000187:drug effects; D052638:Particulate Matter / Q000032:analysis* / Q000633:toxicity; D013183:Sputum; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D009569:Nitric Oxide; D007501:Iron; D051547:Heme Oxygenase-1