No abstract

No abstract

No abstract

Oxidative stress has an important role in the pathogenesis of asthma. 8-Isoprostane is a prostaglandin (PG)-F2-like compound belonging to the F2 isoprostane class that is produced in vivo by the free radical-catalyzed peroxidation of arachidonic acid. 8-Isoprostane is a biomarker of oxidative stress, and its concentration is increased in the bronchoalveolar lavage fluid of patients with interstitial lung diseases. We measured 8-isoprostane concentrations in exhaled breath condensate in healthy subjects and in patients with mild (steroid naive, n = 12), moderate (inhaled steroid treatment, n = 17), and severe asthma (oral steroid treatment, n = 15). We also measured exhaled carbon monoxide (CO) and nitric oxide (NO), which may also reflect oxidative stress in the airways. 8-Isoprostane was detectable in breath condensate of normal subjects (15.8 +/- 1.6 pg/ml), and was increased in the breath condensate of patients with mild (33.7 +/- 2.8, p < 0.001), moderate (38.3 +/- 3.7 pg/ml, p < 0. 001), and severe asthma (48.9 +/- 5.0 pg/ml, p < 0.001). There was a positive correlation (r = 0.68, p < 0.05) of 8-isoprostane with NO, but not with CO, in the exhaled air of patients with mild asthma, but not in that of patients with moderate or severe asthma. There was no correlation between 8-isoprostane and lung function tests in any group of patients. Our study shows that oxidative stress is increased in asthmatic subjects as reflected by 8-isoprostane concentrations in breath condensate.

steroids 4 and the levels are not modulated by bronchodilator therapy. 5 However, in asthmatic Background -Eosinophils in induced sputum and exhaled nitric oxide (NO) are subjects receiving inhaled corticosteroids the levels are reduced. 6 This suggests that exhaled currently used as non-invasive markers in the assessment of airway inflammation in NO may be used as a surrogate marker of airway inflammation. asthma. As both sputum eosinophils (%) and exhaled NO are raised in asthmaticThe number of sputum eosinophils and the amount of eosinophil cationic protein (ECP) subjects not receiving inhaled steroids and decreased following corticosteroid in induced sputum is associated with asthma severity. There are correlations between sputherapy, a relationship between them is plausible.tum eosinophils and sputum ECP levels with FEV 1 . 7-9 Also, sputum obtained from asthMethods -Exhaled NO was measured by chemiluminescence analyser, sputum in-matics under exacerbation contain very high numbers of eosinophils 7 10 11 but they are reduction by 3.5% saline inhalation, and bronchial responsiveness was measured as duced following corticosteroid treatment. 13This evidence justifies the validity of using PC 20 FEV 1 methacholine in 35 stable asthmatic patients using 2 agonist alone and sputum eosinophil number or sputum levels of ECP to monitor asthma severity. the correlation between these non-invasive markers of airway inflammation was Bronchial hyperresponsiveness (BHR), an exaggerated bronchoconstrictor response to instudied. Results -There were significant cor-haled stimuli, is a key feature of asthma and may be used as an indicator of asthma severity. relations between exhaled NO and PC 20 (r=−0.64), exhaled NO and sputum eos-BHR relates closely to the severity of asthma, the frequency of symptoms, and the need for inophils (%) (r=0.48), and also between sputum eosinophils (%) and PC 20 (r= treatment.14 The aim of our study was to examine the −0.40). Conclusion -The correlation between ex-relationship between exhaled NO and other non-invasive markers of inflammation, inhaled NO and PC 20 suggests that exhaled NO or the mechanisms leading to its in-cluding the number of eosinophils, the amount of ECP in induced sputum, and BHR, and also crease may contribute to airway hyperresponsiveness in asthma. Furthermore, its relationship with % predicted FEV 1 . Such a correlation would allow us to evaluate the the relationship between sputum eosinophils (%), exhaled NO, and PC 20 high-clinical utility of exhaled NO and its potential as a surrogate marker of airway inflammation light the potential use of eosinophils (%) in induced sputum and exhaled NO to in asthma. monitor the severity of asthma. (Thorax 1998;53:91-95)