Exhaled Breath Condensate Of Subjects Research Articles

The role of obstructive sleep apnea syndrome and obesity in determining leptin in the exhaled breath condensate

Leptin plays a key role in obstructive sleep apnea syndrome (OSAS). Leptin production in human airways has been previously evaluated by measuring leptin concentration in the exhaled breath condensate and in the induced sputum. The aim was to study leptin expression in the cells of induced sputum and in exhaled breath condensate of subjects with OSAS. Moreover, leptin concentrations in the blood were measured in the same groups of subjects. We enrolled four groups of patients: (1) obese patients with OSAS (OO); (2) non-obese patients with OSAS (NOO); (3) obese patients without OSAS (ONO); and (4) non-obese subjects without OSAS (C). Leptin expression was evaluated by immunocytochemistry in the sputum cells of the enrolled subjects. The concentrations of leptin in the exhaled breath condensate and plasma were measured by using a specific enzyme immunoassay. Leptin protein expression and the percentage of macrophages and neutrophils expressing leptin were higher in the induced sputum of OO, NOO and ONO patients than in C. Leptin concentrations in the exhaled breath condensate were significantly higher in OO patients (5.12 (3.8–6.6) ng ml−1) than in NOO (4.1 (3.9–5.2) ng ml−1) and ONO (4.2 (3.6–5.0) ng ml−1) patients. The concentration of leptin in plasma was significantly more elevated in OO (36 (24–65.9) ng ml−1) than in NOO (30.2 (12.4–51.4) ng ml−1), whereas it was not significantly different in ONO patients. This study showed that leptin in sputum and in the exhaled breath condensate is higher in obese patients with OSAS than in obese subjects without OSAS. Moreover, different mechanisms for determining leptin concentrations in the exhaled breath condensate and the blood are suggested.

Effect of Montelukast on Exhaled Nitric Oxide and Nonvolatile Markers of Inflammation in Mild Asthma

Leukotriene receptor antagonists appear to exert anti-inflammatory activity in asthma. We undertook the present study to evaluate the effect of montelukast on levels of exhaled nitric oxide (ENO) and two inflammatory markers, hydrogen peroxide (H(2)O(2)), and cysteinyl leukotrienes (cys-LTs), in the exhaled breath condensate of subjects with mild asthma. Twenty stable subjects with mild asthma (15 women and 5 men; mean [+/- SD] age, 34.8 +/- 12.6 years) were included in the study. A 1-week run-in period was followed by 2 weeks of treatment (with montelukast or placebo) that was administered in randomized, double-blind, crossover fashion. One week of washout followed each treatment arm. Montelukast significantly reduced the levels of ENO from baseline (median, 52.5 parts per billion [ppb]; 25th to 75th percentile, 37.8 to 101.8 ppb) during the entire treatment period (ie, day 1 to day 14), with the effect measurable as early as day 1 (median, 45.9 ppb; 25th to 75th percentile, 29.3 to 92.5 ppb) and with the maximal effect being observed on day 7 (median, 35.7 ppb; 25th to 75th percentile, 27.6 to 66.6 ppb). The levels of ENO did not change significantly with placebo therapy. Montelukast improved symptom score and reduced peak expiratory flow (PEF) variability. Changes in PEF variability correlated positively with changes in ENO (r = 0.46; p = 0.04). No significant changes in FEV(1) or concentration of H(2)O(2) in the exhaled breath condensate were observed. Levels of cys-LTs were undetectable in the exhaled breath condensate. We concluded that montelukast reduces the levels of ENO in patients with mild asthma, a finding that is compatible with an anti-inflammatory effect of montelukast, and that ENO appears to be more sensitive in detecting this effect than FEV(1) and H(2)O(2) levels in the exhaled breath condensate.

Nitrate in exhaled breath condensate of patients with different airway diseases

There is an increasing interest in the measurement of nitric oxide (NO ) in the airways. NO is a free radical that reacts rapidly with reactive oxygen species in aqueous solution to form peroxynitrite which can then break down to nitrite (NO 2 −) and nitrate (NO 3 −). NO 3 − is considered a stable oxidative end product of NO metabolism. The aim of this study was to assay NO 3 − in exhaled breath condensate (EBC) of normal nonsmoking and smoking subjects, asthmatics, patients with obstructive pulmonary disease (COPD), and patients with community-acquired pneumonia (CAP). EBC was collected using a glass condenser and samples were assayed for NO 3 − by ion chromatography followed by conductivity measurement. NO 3 − was detectable in EBC of all subjects. NO 3 − was elevated in smokers [median (range)] [62.5 (9.6–158.0) μM] and in asthmatics [68.0 (25.8–194.6) μM] compared to controls [9.6 (2.6–119.4) μM; p=0.003 and p=0.006, respectively], whereas NO 3 − was not elevated in COPD patients [24.1 (1.9–337.0) μM]. The concentration of NO 3 − in patients with CAP [243.4 (26.1–584.5) μM] was higher than that in controls ( p=0.002) and NO 3 − values decreased after treatment and recovery from illness [40.0 (4.1–167.0) μM, p=0.009]. This study shows that NO 3 − is detectable in EBC of healthy subjects and it varies in patients with inflammatory airway diseases.

Increased Nitrosothiols in Exhaled Breath Condensate in Inflammatory Airway Diseases

Nitrosothiols (RS-NOs) are formed by interaction of nitric oxide (NO) with glutathione and may limit the detrimental effect of NO. Because NO generation is increased in airway inflammation, we have measured RS-NOs in exhaled breath condensate in patients with asthma, cystic fibrosis, or chronic obstructive pulmonary disease (COPD). We also measured exhaled NO and nitrite (NO(2-)) in the same subjects. RS-NOs were detectable in exhaled breath condensate of all subjects. RS-NOs were higher in subjects with severe asthma (0.81 +/- 0.06 microM) when compared with normal control subjects (0.11 +/- 0.02 microM, p < 0.01) and with subjects with mild asthma (0.08 +/- 0.01 microM, p < 0.01). Elevated RS-NOs values were also found in patients with cystic fibrosis (0.35 +/- 0.07 microM, p < 0.01), in those with COPD (0.24 +/- 0.04 microM, p < 0.01) and in smokers (0.46 +/- 0.09 microM, p < 0.01). In current smokers there was a correlation (r = 0.8, p < 0.05) between RS-NOs values and smoking history (pack/year). We also found elevated concentrations of NO(2-) in patients with severe asthma, cystic fibrosis, or COPD, but not in smokers or patients with mild asthma. This suggests that exhaled NO(2-) is less sensitive than exhaled RS-NOs. This study has shown that RS-NOs are detectable in exhaled breath condensate of healthy subjects and are increased in patients with inflammatory airway diseases. As RS-NOs concentrations in exhaled breath condensate vary in the different airway diseases and increase with the severity of asthma, their measurement may have clinical relevance as a noninvasive biomarker of nitrosative stress.