title: Increased hydrogen peroxide concentration in the exhaled breath condensate of stable COPD patients after nebulized N-acetylcysteine.
abstract: BACKGROUND
  The oxidative burden in the airways is a hallmark of chronic obstructive pulmonary disease (COPD).
  
  
  OBJECTIVE
  This prospective, cross-over, placebo (PL)-controlled study was designed to investigate the effect of N-acetyl-l-cysteine (NAC) on hydrogen peroxide (H(2)O(2)), nitrites and nitrates (NO(2)(-)+NO(3)(-)), and thiol (RSH) concentrations in exhaled breath condensate (EBC) in stable COPD patients (n=19, aged 52.6+/-15.6 years, 10 females, mean FEV(1) 95.2+/-23.8%, FEV(1)/FVC 69.1+/-11.4%).
  
  
  METHODS
  H(2)O(2), NO(2)(-)+NO(3)(-) and RSH concentrations in EBC were determined with homovanillic acid, NADPH-nitrite reductase assays and Ellman's reaction, respectively.
  
  
  RESULTS
  Thirty minutes after nebulization, H(2)O(2) concentration increased if levels after NAC (0.45+/-0.25microM) and PL (0.17+/-0.17microM) were compared in COPD patients (p=0.002). This increased H(2)O(2) level in EBC was no longer observed either after 90min: 0.16+/-0.09microM (PL 0.17+/-0.15microM) or 3h: 0.12+/-0.07microM (PL 0.21+/-0.23microM) (p=0.5 and 0.2, respectively). The levels of NO(2)(-) and NO(3)(-) did not differ between NAC and PL. There was no significant difference in RSH levels between nebulized NAC and PL. After nebulized NAC, however, exhaled RSH increased from 1.42+/-1.69microM (0min) to 2.49+/-2.00microM (30min), and 1.71+/-1.83microM (180min) (p=0.009 and 0.03, respectively, compared with 0min).
  
  
  CONCLUSIONS
  These data demonstrate that nebulized NAC transiently increases exhaled H(2)O(2) level, whereas it has no effect on other oxidative parameters.
authors.affiliation: 2nd Department of Family Medicine, Medical University of Lodz, Zeromskiego St. 113, 90-549 Lodz, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Rysz
authors.forename: Robert A
authors.initials: RA
authors.lastname: Stolarek
authors.forename: Rafal
authors.initials: R
authors.lastname: Luczynski
authors.forename: Agata
authors.initials: A
authors.lastname: Sarniak
authors.forename: Anna
authors.initials: A
authors.lastname: Wlodarczyk
authors.forename: Marek
authors.initials: M
authors.lastname: Kasielski
authors.forename: Dariusz
authors.initials: D
authors.lastname: Nowak
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D000704:Analysis of Variance; D001944:Breath Tests / Q000379:methods; D018592:Cross-Over Studies; D004311:Double-Blind Method; D045853:Exhalation; D005100:Expectorants / Q000008:administration & dosage / Q000627:therapeutic use; D005105:Expiratory Reserve Volume / Q000187:drug effects*; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000187:drug effects; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009330:Nebulizers and Vaporizers; D009566:Nitrates / Q000032:analysis / Q000378:metabolism; D009573:Nitrites / Q000032:analysis / Q000378:metabolism; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D013438:Sulfhydryl Compounds / Q000032:analysis / Q000378:metabolism
chemical_list: D005100:Expectorants; D009566:Nitrates; D009573:Nitrites; D013438:Sulfhydryl Compounds; D006861:Hydrogen Peroxide; D000111:Acetylcysteine