validity of exhaled nitric oxide [NO] in breath condensate in the evaluation of controlled asthma

Nitric oxide was recognized as a key signaling molecule in a wide variety of biological functions, and NO research affects all branches of medicine. In the lung, NO acts as a vasodilator, bronchodilator and non-adrenergic non-cholinergic [NANC] neurotransmitter and is an important mediator of the inflammatory response. Nitric oxide is formed in the lungs and the presence of NO has been detected in the exhaled air of several species, including humans. The aim of the present work to evaluate the validity of exhaled nitrite and nitrate level in exhaled breath condensate in evaluating cases of controlled asthma. The study included 61 subjects: 49 controlled asthmatic patients and 12 control subjects All subjects in the present study were subjected to spirometric study, collection of exhaled breath condensate, breath condensate analysis using nitrite assays, pH measurement. The asthmatic group was further subdivided into two groups: [group I a] including 34 patients receiving anti inflammatory treatment [inhaled corticosteroid] and [group I b] including 15 patients receiving bronchodilators [Beta 2 agonist or theophylline]. Exhaled nitric oxide end product level was significantly higher in asthmatic patients than in control subjects. Asthmatic patients receiving inhaled corticosteroid therapy had a significantly lower exhaled nitric oxide end product level than the others .Breath condensate pH was significantly lower in asthmatic patients than in control subjects. Asthmatic patients receiving inhaled corticosteroid therapy had a significantly higher breath condensate pH than the other patients. Exhaled nitric oxide end product and breath condensate pH reflect the degree of airway inflammation and airway obstruction in stable asthmatic patients. Hence, they could both provide a valuable tool for early disease management and prevention