Exhaled nitric oxide and hydrogen peroxide concentrations in asthmatic smokers.
BACKGROUND
Cigarette smoking is associated with decreased nitric oxide (NO) production and increased oxidative stress in the airways. Exhaled NO levels are not higher in asthmatic smokers than in healthy non-smokers, and the value of exhaled NO for diagnosing asthma in smokers has been questioned.


OBJECTIVE
To compare exhaled NO concentrations between healthy and steroid-naive and steroid-treated asthmatic smokers and non-smokers. To also assess the acute effect of cigarette smoking on exhaled NO and hydrogen peroxide (H(2)O(2)) levels in asthmatic smokers.


METHODS
Exhaled NO was measured by chemiluminescence and exhaled H(2)O(2) spectrophotometrically. In 7 steroid-naive asthmatic smokers exhaled NO and H(2)O(2) was measured both before and 15 min after smoking one cigarette. Data are given as median (range).


RESULTS
Exhaled NO level was significantly higher in steroid-naive asthmatic smokers than in healthy smokers [7.7 (3.4-32.5) ppb vs. 3.2 (2.0-7.2) ppb, p < 0.001]. Exhaled NO values were lower in smokers than in non-smokers both in healthy subjects and in steroid-naive asthmatic patients. Steroid-treated asthmatic smokers had a tendency for lower exhaled NO values [5.4 (1.7-12.0) ppb] compared to steroid-naive asthmatic smokers. Cigarette smoking caused an acute increase in exhaled H(2)O(2) concentrations together with a decrease in exhaled NO concentration.


CONCLUSIONS
Our data suggest that an elevation in exhaled NO concentration is associated with asthma in smokers. This difference may be useful for diagnosing the disease in smokers, but its clinical value needs further evaluation. Acute increase in exhaled H(2)O(2) concentrations suggests that smoking increases the oxidative stress in the asthmatic airways.
Horváth
Ildikó
I
Department of Pathology, National Koranyi Institute for Pulmonology, HU-1529 Budapest, Hungary. hildiko@koranyi.hy
Donnelly
Louise E
LE
Kiss
András
A
Balint
Beata
B
Kharitonov
Sergei A
SA
Barnes
Peter J
PJ
D000328:Adult; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D016022:Case-Control Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide; D008163:Luminescent Measurements; D008297:Male; D009569:Nitric Oxide; D009994:Osmolar Concentration; D012907:Smoking; D013053:Spectrophotometry; D013256:Steroids / Q000627:therapeutic use; D013997:Time Factors
D013256:Steroids; D009569:Nitric Oxide; D006861:Hydrogen Peroxide