Increased levels of nitric oxide derivatives in induced sputum in patients with asthma.
BACKGROUND
Nitric oxide (NO) plays an important role as an inflammatory mediator in the airways. However, because direct measurement of endogenous NO has been difficult in vivo, the exact pathologic roles of NO in human airway inflammation have remained unclear.


OBJECTIVE
This study was designed to determine whether NO may be harmful by amplifying allergic inflammation in asthmatic airways.


METHODS
In this study we examined the concentration of stable end products of NO, nitrite and nitrate, in induced sputum in 18 patients with asthma and 10 normal control subjects and evaluated the relationship between levels of NO derivatives in sputum and cellular and biochemical profiles, the degree of airflow obstruction, and the cytotoxic activities for epithelial cells.


RESULTS
The concentration of NO derivatives in induced sputum was significantly higher in patients with asthma than in normal control subjects (1086 +/- 325 mumol/L, 577 +/- 115 mumol/L; p < 0.05). Percentages of eosinophil counts and eosinophil cationic protein levels in sputum were also significantly higher in patients with asthma. Moreover, percentages of eosinophil counts and eosinophil cationic protein levels in sputum in patients with asthma were significantly correlated with the concentration of NO derivatives in sputum (r = 0.63, p < 0.01; r = 0.56, p < 0.05, respectively). In addition, we found that the concentration of NO derivatives in sputum in patients with asthma was significantly correlated with the degree of airflow obstruction (FEV1/forced vital capacity) (r = -0.62, p < 0.01) and with percentages of shedding epithelial cells (r = 0.61, p < 0.01).


CONCLUSIONS
We have shown that a higher concentration of NO derivatives was found in induced sputum of patients with asthma as compared with normal subjects. The clinical implication of our findings is that measurement of NO derivatives in induced sputum may be useful for assessing allergic inflammation in airways.
Kanazawa
H
H
First Department of Internal Medicine, Osaka City University Medical School, Japan.
Shoji
S
S
Yamada
M
M
Fujii
T
T
Kawaguchi
T
T
Kudoh
S
S
Hirata
K
K
Yoshikawa
J
J
D000328:Adult; D000368:Aged; D001249:Asthma / Q000378:metabolism*; D001798:Blood Proteins / Q000032:analysis; D047091:Eosinophil Granule Proteins; D004804:Eosinophils; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000032:analysis*; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000032:analysis*; D012260:Ribonucleases; D013183:Sputum / Q000737:chemistry* / Q000166:cytology
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D012260:Ribonucleases