Peroxynitrite elevation in exhaled breath condensate of COPD and its inhibition by fudosteine.
BACKGROUND
Peroxynitrite (PN) formed by the reaction of nitric oxide and superoxide is a powerful oxidant/nitrosant. Nitrative stress is implicated in COPD pathogenesis, but PN has not been detected due to a short half-life (< 1 s) at physiologic condition. Instead, 3-nitrotyrosine has been measured as a footprint of PN release.


METHODS
PN was measured using oxidation of 2',7'-dichlorofluorescein (DCDHF) in exhaled breath condensate (EBC) collected in high pH and sputum cells. The PN scavenging effect was also evaluated by the same system as PN-induced bovine serum albumin (BSA) nitration.


RESULTS
The mean (+/- SD) PN levels in EBC of COPD patients (7.9 +/- 3.0 nmol/L; n = 10) were significantly higher than those of healthy volunteers (2.0 +/- 1.1 nmol/L; p < 0.0001; n = 8) and smokers (2.8 +/- 0.9 nmol/L; p = 0.0017; n = 6). There was a good correlation between PN level and disease severity (FEV(1)) in COPD (p = 0.0016). Fudosteine (FDS), a unique mucolytic antioxidant, showed a stronger scavenging effect of PN than N-acetyl-cysteine on DCDHF oxidation in vitro and in sputum macrophages, and also on PN-induced BSA nitration. FDS (0.1 mmol/L) reduced PN-enhanced interleukin (IL)-1beta-induced IL-8 release and restored corticosteroid sensitivity defected by PN more potently than those induced by H(2)O(2) in A549 airway epithelial cells.


CONCLUSIONS
This noninvasive PN measurement in EBC may be useful for monitoring airway nitrative stress in COPD. Furthermore, FDS has the potential to inhibit PN-induced events in lung by its scavenging effect.
Osoata
Grace O
GO
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Hanazawa
Toyoyuki
T
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Brindicci
Caterina
C
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Ito
Misako
M
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Barnes
Peter J
PJ
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Kharitonov
Sergei
S
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
Ito
Kazuhiro
K
Airway Disease Section, National Heart and Lung Institute, Imperial College London, London, UK. Electronic address: k.ito@imperial.ac.uk.
D000328:Adult; D000368:Aged; D001944:Breath Tests; D016022:Case-Control Studies; D003553:Cystine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006207:Half-Life; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D030421:Peroxynitrous Acid / Q000378:metabolism*; D010865:Pilot Projects; D011336:Probability; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000188:drug therapy*; D012016:Reference Values; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology / Q000378:metabolism
D018836:Inflammation Mediators; D016209:Interleukin-8; D030421:Peroxynitrous Acid; D009569:Nitric Oxide; D003553:Cystine; C113797:fudosteine