Nitric oxide metabolites in induced sputum: a noninvasive marker of airway inflammation in asthma.
OBJECTIVE
This study was designed to examine for nitric oxide (NO) metabolites in induced sputum as a marker of airway inflammation in asthmatic children. DESIGN. Prospective interventional


METHODS
Pediatric Allergy and Asthma Clinic of a tertiary care referral hospital in Northern India.


METHODS
Twenty-one children with asthma who were not receiving corticosteroids for the preceding 3 months and 10 healthy controls were enrolled.


METHODS
Hypertonic saline-induced sputum was obtained at study entry in controls, and at study entry and after 6 weeks of inhaled corticosteroid (ICS) therapy in asthmatic children. Fresh expectorated sputum was treated with dithiothreitol and cytospinned for cell count. NO metabolites were measured in the supernatant by the modified Griess reaction.


RESULTS
Asthmatic children, compared with controls, had significantly higher concentration of NO metabolites (22.4 +/- 209.69 vs 39.2 +/- 15.9 (moL/L, P <0.01) and a higher percentage of eosinophils (15.3 +/- 12.0 vs 0.8 +/- 1.1%, P <0.01) in induced sputum. Both NO metabolites and eosinophil percentage declined following treatment with ICS for 6 weeks (P <0.01).


CONCLUSIONS
The study confirms that the level of NO metabolites is increased in the tracheobronchial secretions of asthmatic children and decreases following ICS therapy. Measurement of NO metabolites in induced sputum may be useful for monitoring airway inflammation in children with asthma.
Kumar
Lata
L
Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh160 012, India.
Rajput
Nitin
N
Majumdar
Siddhartha
S
D000293:Adolescent; D001249:Asthma / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D001980:Bronchi / Q000378:metabolism*; D002648:Child; D004804:Eosinophils; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D007958:Leukocyte Count; D009569:Nitric Oxide / Q000378:metabolism*; D010366:Peak Expiratory Flow Rate; D011446:Prospective Studies; D013183:Sputum / Q000378:metabolism*
D015415:Biomarkers; D009569:Nitric Oxide