RESUMO
BACKGROUND: Exhaled breath condensate (EBC) 8-isoprostane levels were found increased in chronic obstructive pulmonary disease. However, the relation between EBC 8-isoprostane and parameters which have a known predictive value in COPD, remains vastly unknown, and so does subsequently its clinical value. OBJECTIVES: To investigate the relationship between 8-isoprostane level in EBC and clinical parameters, radiological indices and airway inflammation in COPD patients. MATERIALS AND METHODS: We studied 18 COPD patients (all ex-smokers) and 12 healthy controls (5 ex-smokers and 7 never-smokers). All patients underwent clinical evaluation, sputum induction, high-resolution computed tomography (HRCT) of the thorax and EBC 8-isoprostane measurement. 8-Isoprostane levels were correlated with markers that reflect disease severity, such as dyspnea severity, FEV(1) (%pred), emphysema changes and bronchiectasis in HRCT. Emphysema was quantified as the percentage of lung area with attenuation values < -950 Hounsfield units. RESULTS: 8-Isoprostane levels were significantly elevated in EBC of patients with COPD [mean (SE) 18.1 (2) vs. 5.6 (0.7) pg/ml, p = 0.0001], irrespective of lung function impairment. 8-Isoprostane levels were correlated with emphysema score in HRCT (r(2) = 0.43, p = 0.001) as well as with Medical Research Council dyspnea scale score (rho = 0.61, p = 0.005). CONCLUSION: Our findings suggest that EBC 8-isoprostane levels may reflect the extension of lung emphysema in COPD patients. In this respect, further investigation is required in order to evaluate the possible role of EBC 8-isoprostane in assessing disease progress in COPD patients.