Decreased peroxynitrite inhibitory activity in induced sputum in patients with bronchial asthma.
BACKGROUND
The production of peroxynitrite, an extremely potent oxidant, is increased in inflammatory lung disease. It is therefore important to measure antioxidant activity against peroxynitrite in epithelial lining fluid to examine the physiological effects of peroxynitrite in the airways of patients with asthma. This study was designed to determine whether peroxynitrite inhibitory activity in induced sputum is correlated with clinical characteristics and airway inflammatory indices in asthmatic patients.


METHODS
Inflammatory indices were measured in induced sputum from 25 patients with asthma and 12 normal control subjects. Peroxynitrite inhibitory activity was also measured by monitoring rhodamine formation in sputum samples.


RESULTS
Peroxynitrite inhibitory activity in induced sputum was significantly lower in asthmatic patients (52.4 (24.5)%) than in normal control subjects (92.1 (3.9)%, p<0.0001). Its activity was significantly correlated with forced expiratory volume in 1 second (FEV(1)) % predicted (r=0.774, p<0.0001) and bronchial hyperreactivity to methacholine (r=0.464, p=0.023). There was a significant negative correlation between peroxynitrite inhibitory activity and the degree of eosinophilic airway inflammation (% eosinophils, r=-0.758, p<0.0001; eosinophil cationic protein, r=-0.780, p<0.0001).


CONCLUSIONS
Decreased peroxynitrite inhibitory activity occurs in induced sputum of asthmatic patients. Since even in patients with stable asthma the airway lining fluid lacks peroxynitrite inhibitory activity, large amounts of peroxynitrite, which are further increased during an acute asthma attack, would not be completely inactivated and asthmatic airways might have markedly increased susceptibility to peroxynitrite induced airway injury.
Kanazawa
H
H
Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3 Asahi-machi, Abenoku, 545-8585, Japan. kanazawa-h@med.osaka-cu.ac.jp
Shiraishi
S
S
Hirata
K
K
Yoshikawa
J
J
D000328:Adult; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology; D001798:Blood Proteins / Q000378:metabolism; D001980:Bronchi / Q000187:drug effects; D001985:Bronchial Provocation Tests; D047091:Eosinophil Granule Proteins; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D030421:Peroxynitrous Acid / Q000378:metabolism / Q000502:physiology*; D012260:Ribonucleases; D013183:Sputum / Q000378:metabolism
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D016210:Methacholine Chloride; D030421:Peroxynitrous Acid; D012260:Ribonucleases