title: Exhaled markers of oxidative stress in idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  Expired breath condensate (EBC) has never been used to explore the level of oxidative stress in idiopathic pulmonary fibrosis (IPF). Therefore, the aim of this study was to measure the levels of H2O2 and 8-isoprostane, as biomarkers of oxidative stress, in the EBC of patients with IPF.
  
  
  METHODS
  We investigated 16 patients with IPF and 15 healthy subjects as the control group. The levels of H2O2 and 8-isoprostane were measured in the EBC of all subjects and were compared between the IPF and control groups. In patients with IPF, H2O2 and 8-isoprostane were further correlated with pulmonary function tests (PFTs), the resting pO2 and the differential cell count from the bronchoalveolar lavage fluid (BALF).
  
  
  RESULTS
  The mean (95%CI) concentration of H2O2 was increased in the patients with IPF compared with the normal subjects (0.36, 0.24-0.47 microM vs. 0.16, 0.10-0.23 microM, P=0.003). The mean (95%CI) concentration of 8-isoprostane was also increased in the patients with IPF compared with the controls (74, 38-110 pg mL-1 vs. 33, 28-39 pg mL-1, P=0.02). In the patients with IPF, the diffusing capacity of the lung for carbon monoxide was negatively correlated with the levels of H2O2 in EBC (P=0.03, r=-0.58). No other correlation was found between the oxidative stress markers in the EBC and PFT values, pO2 or BALF cell count.
  
  
  CONCLUSIONS
  Our data suggest that H2O2 and 8-isoprostane are increased in the EBC of patients with IPF. H2O2 may be correlated with the severity of the disease in IPF.
authors.affiliation: Department of Pneumonology and the Clinical Research Unit, Army General Hospital of Athens, and Department of Pneumonology, University Hospital of Heraklion, Greece. kpsazakis@hol.gr
authors.forename: K
authors.initials: K
authors.lastname: Psathakis
authors.forename: D
authors.initials: D
authors.lastname: Mermigkis
authors.forename: G
authors.initials: G
authors.lastname: Papatheodorou
authors.forename: S
authors.initials: S
authors.lastname: Loukides
authors.forename: P
authors.initials: P
authors.lastname: Panagou
authors.forename: V
authors.initials: V
authors.lastname: Polychronopoulos
authors.forename: N M
authors.initials: NM
authors.lastname: Siafakas
authors.forename: D
authors.initials: D
authors.lastname: Bouros
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests / Q000379:methods; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002452:Cell Count; D015237:Dinoprost / Q000031:analogs & derivatives / Q000032:analysis; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D011658:Pulmonary Fibrosis / Q000378:metabolism / Q000503:physiopathology*; D012129:Respiratory Function Tests; D014109:Total Lung Capacity
chemical_list: D015415:Biomarkers; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D006861:Hydrogen Peroxide