title: Nitrite in exhaled breath condensate as a marker of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis.
abstract: BACKGROUND
  Nitrite and nitrate are exhaled in droplets of an aerosol during breathing and can be assayed in the exhaled breath condensate (EBC) as markers of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis (IPF).
  
  
  METHODS
  Using HPLC with fluorescence detection, nitrite and nitrate were assayed in EBC of 14 atopic patients with mild-to-moderate stable asthma, 18 atopic asthmatics with exacerbation, 14 COPD patients without exacerbation, 18 patients with exacerbated COPD, 13 patients with active IPF, and in 29 healthy subjects.
  
  
  RESULTS
  The geometric mean [exp(mean±SD)] EBC concentrations of nitrite (micromol/l) in patients with asthma [5.1(2.1-12.3)], exacerbation of asthma [5.1(2.8-9.6)], exacerbation of COPD [5.3(3.2-8.7)], and with IPF [5.5(2.9-10.2)] were higher (P<0.05) compared with those of healthy subjects [2.9(1.6-5.3)] and patients with stable COPD [3.0(1.3-6.7)]. Nitrite concentration increased with decreased lung function of patients with asthma (r(s)=-0.31, P<0.02). Presumably owing to the contamination of the EBC sample with nitrate during collection, nitrate levels were highly variable among healthy subjects and higher compared with all groups of patients.
  
  
  CONCLUSIONS
  EBC nitrite is a suitable marker of nitrossative stress in adult patients with lung diseases but cannot differentiate controlled and exacerbated asthma. Further improvements to the methods of EBC collection and sample handling are warranted.
authors.affiliation: Department of Respiratory Diseases, Regional Thomas Bata Hospital, Havlíckovo nábrezí, Zlín, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Rihák
authors.forename: Petr
authors.initials: P
authors.lastname: Zatloukal
authors.forename: Jirina
authors.initials: J
authors.lastname: Chládková
authors.forename: Alena
authors.initials: A
authors.lastname: Zimulová
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Havlínová
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Chládek
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism*; D001944:Breath Tests; D016022:Case-Control Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009573:Nitrites / Q000378:metabolism*; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism*; D012137:Respiratory System; D013312:Stress, Physiological
chemical_list: D015415:Biomarkers; D009573:Nitrites