Acid-base equilibrium in exhaled breath condensate of allergic asthmatic children

BACKGROUND: The dysregulation of airway pH control may have a role in asthma pathophysiology. The measurement of exhaled breath condensate (EBC) pH and ammonia levels may be used as a noninvasive method to study acid-base status in the airway of asthmatics. METHODS: Exhaled breath condensate from 29 allergic stable asthmatic children and 13 healthy controls was collected by cooling exhaled air during tidal breathing. Ammonia was measured by high-performance liquid chromatography with fluorescence detection. pH was measured after deaeration of EBC samples by bubbling with argon. The children also underwent FENO measurement. RESULTS: Both pH and ammonia values in EBC were significantly lower in the asthmatics than in the control group [pH: ICS-treated (median and interquartile range) 7.70 (7.62-7.74), steroid-naive 7.53 (7.41-7.68), controls 7.85 (7.80-7.90), P <0.01 and P <0.001, respectively; ammonia: ICS-treated 476.17 microM (282.50-594.80), steroid-naive 253.24 microM (173.43-416.08), controls 788.30 microM (587.29-1310.39), P < 0.05 and P <0.001, respectively]. Both pH and ammonia values were higher in ICS-treated than in steroid-naive asthmatic children. There was a significant correlation between EBC pH and ammonia concentrations. CONCLUSIONS: These data show that EBC pH values of stable asthmatic children are lower compared with those of healthy controls and positively correlated with ammonia concentrations, supporting the hypothesis that airway acidification may have a role in the pathobiology of allergic asthma.     

Effects of inhaled corticosteroids on exhaled leukotrienes and prostanoids in asthmatic children

BACKGROUND: Lipid mediators play an important pathophysiologic role in atopic asthmatic children, but their role in the airways of atopic nonasthmatic children is unknown. OBJECTIVE: We sought (1) to measure leukotriene (LT) E 4 , LTB 4 , 8-isoprostane, prostaglandin E 2 , and thromboxane B 2 concentrations in exhaled breath condensate in atopic asthmatic and atopic nonasthmatic children; (2) to measure exhaled nitric oxide (NO) as an independent marker of airway inflammation; and (3) to study the effect of inhaled corticosteroids on exhaled eicosanoids. METHODS: Twenty healthy children, 20 atopic nonasthmatic children, 30 steroid-naive atopic asthmatic children, and 25 atopic asthmatic children receiving inhaled corticosteroids were included in a cross-sectional study. An open-label study with inhaled fluticasone (100 microg twice a day for 4 weeks) was undertaken in 14 steroid-naive atopic asthmatic children. RESULTS: Compared with control subjects, exhaled LTE 4 ( P <.001), LTB 4 ( P <.001), and 8-isoprostane ( P <.001) levels were increased in both steroid-naive and steroid-treated atopic asthmatic children but not in atopic nonasthmatic children (LTE 4 , P=.14; LTB 4 , P=.23; and 8-isoprostane, P=.52). Exhaled NO levels were increased in steroid-naive atopic asthmatic children ( P <.001) and, to a lesser extent, in atopic nonasthmatic children ( P <.01). Inhaled fluticasone reduced exhaled NO (53%, P <.0001) and, to a lesser extent, LTE 4 (18%, P <.01) levels but not LTB 4 , prostaglandin E 2 , or 8-isoprostane levels in steroid-naive asthmatic children. Conclusions Exhaled LTE 4 , LTB 4 , and 8-isoprostane levels are increased in atopic asthmatic children but not in atopic nonasthmatic children. In contrast to exhaled NO, these markers seem to be relatively resistant to inhaled corticosteroids.     

Exhaled breath condensate cysteinyl leukotrienes are increased in children with exercise-induced bronchoconstriction

BACKGROUND: It is recognized that airway inflammation has a central role in the pathogenesis of asthma, but how it relates to exercise-induced bronchoconstriction (EIB) is not completely understood. OBJECTIVE: The aim of our study was to investigate the relationship between EIB and baseline concentrations of cysteinyl leukotrienes (Cys-LTs) and other inflammatory markers in exhaled breath condensate (EBC). METHODS: EBC was collected, and the fraction of exhaled nitric oxide (FE NO ) was measured in a group of 19 asthmatic children, after which they performed a treadmill exercise test. Fourteen healthy children were enrolled as control subjects. RESULTS: The asthmatic children were divided into the EIB group (decrease in FEV 1 , > or =12%) and the non-EIB group. The EBC was analyzed for the presence of Cys-LTs, leukotriene B 4 , and ammonia. Asthmatic patients with EIB (mean FEV 1 decrease, 23% +/- 3%) had higher Cys-LT concentrations than either asthmatic patients without EIB or control subjects (42.2 pg/mL [median] vs 11.7 pg/mL and 5.8 pg/mL; P < .05 and P < .001, respectively). Ammonia concentrations were lower in both the EIB and non-EIB groups than in control subjects (253.2 microM and 334.6 microM vs 798.4 microM; P < .01 and P < .05, respectively). No difference in EBC leukotriene B 4 levels was found among the 3 groups. Both asthmatic groups had higher FE NO levels than control subjects ( P < .001). EBC Cys-LT ( P < .01; r = 0.7) and FE NO ( P < .05; r = 0.5) values both correlated significantly with the postexercise FEV 1 decrease. CONCLUSION: this study shows that EBC Cys-LT values are higher in asthmatic children with EIB and correlate with the decrease in FEV 1 after exercise. These findings suggest that the pathways of both Cys-LT and nitric oxide are involved in the pathogenesis of EIB.     

Intranasal steroid reduces exhaled bronchial cysteinyl leukotrienes in allergic patients

BACKGROUND: Allergic rhinitis (AR) precedes and is often associated with bronchial asthma. Indeed, local and systemic inflammations in both conditions are very similar. Cysteinyl-leukotrienes (cys-LTs) are generated during early- and late-phase allergic reactions and induce smooth-muscle contraction, microvascular leakage, and mucous hypersecretion. Cys-LTs are detected in exhaled breath condensate (EBC) of asthmatics and regardless of bronchial symptoms, they are also found in EBC of rhinitic patients. OBJECTIVE: To evaluate cys-LTs in EBC of allergic patients and to assess the activity of nasal fluticasone propionate (FP) on EBC cys-LTs levels. METHODS: Cys-LTs coefficient of variation (CV) was evaluated from different EBC in 5 healthy volunteers. Cys-LTs levels from EBCs in 13 healthy controls and 56 allergic rhinitic (n=31) and rhinitic/asthmatic (n=25) patients were also evaluated at baseline. Subsequently patients were randomized to receive either FP 100 microg/day per nostril or placebo for 2 weeks and then re-evaluated for EBC cys-LTs. RESULTS: The CV was 14.12%. EBC cys-LTs in allergic patients were significantly higher than in healthy subjects (70.9 vs. 20.6 pg/mL (median), P<0.05), while it did not differ between asthmatic/rhinitic and purely rhinitic patients. Treatment significantly reduced cys-LTs (from 93.6 to 19.9 pg/mL, P<0.001). This effect was evident both in asthmatic/rhinitic and in rhinitic patients. CONCLUSION: Treatment of AR with FP significantly reduces the levels of cys-LTs, major noninvasive markers of lower airway inflammation, suggesting that upper and lower airway inflammation is present and should be thus treated as a whole in subjects with AR with and without asthma.     

Soluble interleukin-2 receptor and interleukin-4 in sera of asthmatic children before and after a prednisolone course.

BACKGROUND: Cytokine-mediated interactions among inflammatory cells may play a role in the pathogenesis of bronchial asthma. OBJECTIVE: To understand the role of soluble interleukin-2 receptor (sIL-2R) and interleukin-4 (IL-4) in the disease activity of acute asthma, changes in serum concentrations of sIL-2R and IL-4 elaborated by activated T-lymphocyte before and after prednisolone therapy with clinical improvement were determined in the present study. METHODS: Circulating levels of sIL-2R and IL-4 in sera from 15 normal control subjects and in sera from 20 allergic asthmatic children with acute exacerbation and in a stable condition were determined by using commercially available ELISA kits. RESULTS: The mean concentration of serum sIL-2R was significantly higher in acute exacerbation than in children with stable asthma (368.9 +/- 395.4 pg/mL vs 291.2 +/- 361.0 pg/mL; P < .01) or in control subjects (124.6 +/- 17.8 pg/mL; P < .001). The mean concentration of serum IL-4 was higher in acute exacerbation (5.82 +/- 1.10 pg/mL) and in stable asthmatic patients (6.73 +/- 2.83 pg/mL) versus control group subjects (5.54 +/- 1.20 pg/mL). However, the difference was not statistically significant among the three study groups. CONCLUSIONS: This study provides further evidence that changes in serum IL-2R may serve as an objective indicator for clinical outcome of allergic asthmatic patients.     

3-Nitrotyrosine, a marker of nitrosative stress, is increased in breath condensate of allergic asthmatic children

BACKGROUND: Asthmatic patients have high exhaled nitric oxide (NO) levels. NO-mediated inflammatory actions are mainly due to NO conversion into reactive nitrogen species, which can lead to nitrotyrosine formation. The aim of this study was to assess 3-nitrotyrosine (3-NT) levels in exhaled breath condensate (EBC) of asthmatic and healthy children and to investigate whether there is any relationship with exhaled NO (FE(NO)) and lung function. METHODS: The study included 20 asthmatic children (10 steroid-naive with intermittent asthma, 10 steroid-treated with unstable persistent asthma) and 18 healthy controls. They underwent FE(NO) measurement, EBC collection and spirometry. 3-NT was measured by a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method in isotopic dilution. RESULTS: The median EBC concentration of 3-NT (expressed as nitrotyrosine/tyrosine ratio x 100) in asthmatic children was fivefold higher than in healthy subjects [0.23% (0.12-0.32) vs 0.04% (0.02-0.06), P < 0.001] with no difference between steroid-naive and unstable steroid-treated asthmatic patients. FE(NO) levels were higher in asthmatic [44.6 ppb (36.0-66.0)] than in healthy children [7.5 ppb (6.0-8.8), P < 0.001]. No correlation was found among 3-NT, FE(NO) and lung function parameters. CONCLUSION: Nitrotyrosine is high in EBC of asthmatic children and could be considered as a noninvasive marker of nitrosative events in the airways.     

Inflammatory markers and Acid-base equilibrium in exhaled breath condensate of stable and unstable asthma patients

Background: Nitrosative and acid stress play an important role in the pathogenesis of asthma. The aim of this study was to evaluate whether, in asthmatics, a link exists between the concentrations of nitrite/nitrate, ammonia and pH values in exhaled breath condensate (EBC) and asthma severity, lung function, exhaled nitric oxide (F(ENO)), total IgE, eosinophil cationic protein (ECP) and blood eosinophilia. Methods: The above-mentioned parameters were measured in 19 healthy volunteers and 91 allergic asthmatics divided into three groups, i.e. 22 subjects with steroid-na?ve stable asthma, 35 with inhaled corticosteroid (ICS)-treated stable asthma and 34 with ICS-treated unstable asthma. Results: Compared with healthy subjects, EBC from asthmatics had significantly lower pH values and ammonia concentrations and significantly higher levels of nitrite/nitrate. The extent of these changes was higher in patients with unstable than in patients with steroid-na?ve and stable ICS-treated asthma. The EBC pH was positively correlated with ammonia and negatively correlated with nitrite/nitrate, F(ENO) or blood eosinophilia in all three groups of asthmatics. Significant positive correlations between EBC nitrite/nitrate and blood eosinophilia, ECP levels or F(ENO) were observed in all groups of asthmatics. Significant negative correlations between EBC ammonia and nitrite/nitrate, F(ENO), ECP concentrations or blood eosinophilia were demonstrated in the groups of ICS-na?ve and ICS-treated stable asthmatics. Conclusions: In asthmatic patients there is a relationship between EBC pH, ammonia and nitrite/nitrate concentrations and other recognized markers of airway inflammation. EBC pH values, ammonia and nitrite/nitrate levels measured together may help to assess airway inflammatory status and asthma severity.     

Exhaled leukotrienes and prostaglandins in asthma

BACKGROUND: Most of the studies investigating the role of leukotrienes (LTs) and prostaglandins (PGs) in asthma have used invasive (eg, bronchoalveolar lavage fluid) or semi-invasive (eg, sputum induction) techniques. Others have measured eicosanoids in plasma or urine, probably reflecting systemic rather than lung inflammation. Collection of exhaled breath condensate (EBC) is a noninvasive method to collect airway secretions. OBJECTIVE: We sought to investigate whether eicosanoids are measurable in EBC, to show possible differences in their concentrations in asthmatic patients and healthy subjects, and to investigate whether exhaled eicosanoids correlate with exhaled nitric oxide (NO), a marker of airway inflammation. METHODS: Twelve healthy nonsmokers and 15 steroid-naive patients with mild asthma were studied. Subjects attended on one occasion for pulmonary function tests, collection of EBC, and exhaled NO measurements. Exhaled LTB(4)-like immunoreactivity, LTE(4)-like immunoreactivity, PGE(2)-like immunoreactivity, PGD(2)-methoxime, PGF(2)(alpha)-like immunoreactivity, and thromboxane B(2)-like immunoreactivity were measured by means of enzyme immunoassays. RESULTS: LTE(4)-like immunoreactivity and LTB(4)-like immunoreactivity were detectable in EBC in healthy subjects, and their levels in asthmatic patients were increased about 3-fold (P <.0001) and 2-fold (P <.0005), respectively. Exhaled NO was increased in asthmatic patients compared with healthy subjects (P <.0001). There was a correlation between exhaled LTB(4) and exhaled NO (r = 0.56, P <.04) in patients with asthma. When measurable, prostanoid levels were similar in asthmatic patients and control subjects. CONCLUSIONS: Exhaled LTE(4) and LTB(4) are increased in steroid-naive patients with mild asthma. EBC may be proved to be a novel method to monitor airway inflammation in asthma.     

Eicosanoids in exhaled breath condensate and bronchoalveolar lavage fluid of patients with primary lung cancer

Although eicosanoids are involved in lung carcinogenesis they were poorly investigated in exhaled breath condensate (EBC) and bronchoalveolar lavage fluid (BALf) in patients with primary lung cancer. In this study 17 patients with diagnosed non-small cell lung cancer, 10 healthy smokers and 12 healthy nonsmokers were included. The levels of cys-LTs, 8-isoprostane, LTB4 and PGE2 were measured before any treatment in the EBC of all patients and in BALf of patients with lung cancer by enzyme linked immunosorbent assay. 8-isoprostane, LTB4, cys-LTs and PGE2 were detectable in the EBC and BALf. There were no significant differences between healthy smokers and nonsmokers in concentrations of all measured mediators. Compared with both healthy controls, patients with diagnosed lung cancer displayed higher concentrations of cys-LTs (p< 0.05) and LTB4 (p < 0.05) in EBC. In patients with lung cancer, the mean concentrations of all measured mediators were significantly higher in BALf compared with EBC and there was a significant, positive correlation between concentration of cys-LTs, LTB(4) and 8-isoprostane in BALf and their concentrations in the EBC (r=0.64, p < 0.05, r=0.59, p< 0.05, r=0.53, p< 0.05 respectively). Since cys-LT, LTB4 and 8-isoprostane concentrations in EBC from patients with lung cancer reflect their concentrations in BALf, they may serve as a possible non-invasive method to monitor the disease and to assess the effectiveness of therapy.     

Imbalance between vascular endothelial growth factor and endostatin levels in induced sputum from asthmatic subjects

BACKGROUND: Angiogenesis has recently attracted considerable attention as a component of airway remodeling in bronchial asthma. Vascular endothelial growth factor (VEGF) is highly expressed in asthmatic airways, and its contribution to airway remodeling has been reported. Although angiogenesis is regulated by a balance of angiogenic and antiangiogenic factors, the relative levels of antiangiogenic factors in asthmatic airways have not been evaluated. OBJECTIVE: We sought to determine whether an imbalance between angiogenic and antiangiogenic factors exists in asthmatic airways. METHODS: We simultaneously measured VEGF and endostatin levels and evaluated their correlation and balance in induced sputum from 18 steroid-naive asthmatic subjects and 11 healthy control subjects. After initial sputum induction, asthmatic subjects underwent 8 weeks of inhaled beclomethasone dipropionate (BDP; 800 microg/d) therapy, and sputum induction was then repeated. RESULTS: VEGF and endostatin levels in induced sputum were significantly higher in asthmatic subjects than in control subjects (P <.001). There was a significant correlation between VEGF and endostatin levels in both control subjects (r = 0.995, P <.001) and asthmatic subjects (r = 0.923, P <.001). Moreover, the VEGF/endostatin level ratio in asthmatic subjects was significantly higher than that in control subjects (P <.0001). After 8 weeks of inhaled BDP therapy, the VEGF level in induced sputum in asthmatic subjects was significantly decreased (P <.001), whereas the endostatin level was not. A correlation between VEGF and endostatin levels existed even after BDP therapy (r = 0.861, P <.001). Moreover, the VEGF/endostatin level ratio was significantly decreased to the same level as in the control subjects after BDP therapy (P <.0001). CONCLUSION: There was an imbalance between VEGF and endostatin levels in induced sputum from asthmatic subjects. This imbalance might play an important role in the pathogenesis of bronchial asthma through its effects on angiogenesis.     

Increased macrophage-derived chemokine in exhaled breath condensate and plasma from children with asthma

BACKGROUND: Type 2 helper T lymphocyte-specific chemokines including macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) and eotaxin are important mediators for allergic airway inflammation. OBJECTIVE: We investigated whether these chemokines can be detected in exhaled breath condensate (EBC) and their relation to childhood asthma. METHODS: Asthmatics recruited from paediatric clinics of a university teaching hospital were classified into intermittent asthma (IA) and persistent asthma (PA) according to Global Initiative for Asthma guidelines. EBC was collected by a disposable collection kit, whereas fractional exhaled nitric oxide (FENO) was measured by a chemiluminescence analyser. Concentrations of MDC, TARC and eotaxin in both EBC and plasma were measured using sandwich enzyme immunoassay. The intra-subject reproducibility of exhaled chemokine measurements was determined by co-efficients of variation (CV). RESULTS: Forty-eight patients with PA, 36 children with IA and 18 controls were recruited. MDC and eotaxin were present in EBC from nearly all subjects, whereas TARC could be measured in EBC from 33 (32%) subjects only. The median MDC concentration in EBC was higher in PA (117 pg/mL) as compared with IA (106 pg/mL) and controls (105 pg/mL; P=0.003 for both). The median plasma MDC concentration in PA (648 pg/mL) was also higher than that in IA (520 pg/mL; P=0.002) and controls (490 pg/mL; P=0.008). The median plasma TARC concentration was also increased in PA as compared with IA (72 pg/mL vs. 35 pg/mL; P=0.004). MDC concentrations in EBC were lower in patients with PA who received high-dose inhaled corticosteroid (P=0.005). FENO was significantly higher in asthmatics than controls (P<0.0001), but it was not associated with chemokines in EBC or plasma. The mean (range) CV for measuring MDC, TARC and eotaxin in EBC (n=6) were 5.5 (2.0-7.2%), 8.8 (3.6-14.4%) and 5.2 (2.8-7.9%), respectively. CONCLUSIONS: Our results suggest that MDC in EBC and MDC and TARC in plasma are increased in children with PA as compared with IA or control. MDC concentrations in EBC are suppressed in patients on high-dose inhaled corticosteroid treatment.     

IFN-gamma-induced protein 10 is a novel biomarker of rhinovirus-induced asthma exacerbations

BACKGROUND: Rhinovirus-induced acute asthma is the most frequent trigger for asthma exacerbations. OBJECTIVE: We assessed which inflammatory mediators were released from bronchial epithelial cells (BECs) after infection with rhinovirus and then determined whether they were also present in subjects with acute virus-induced asthma, with the aim to identify a biomarker or biomarkers for acute virus-induced asthma. METHODS: BECs were obtained from bronchial brushings of steroid-naive asthmatic subjects and healthy nonatopic control subjects. Cells were infected with rhinovirus 16. Inflammatory mediators were measured by means of flow cytometry with a cytometric bead array. Subjects with acute asthma and virus infection were recruited; they were characterized clinically by using lung function tests and had blood taken to measure the inflammatory mediators identified as important by the BEC experiments. RESULTS: IFN-gamma-induced protein 10 (IP-10) and RANTES were released in the greatest quantities, followed by IL-6, IL-8, and TNF-alpha. Dexamethasone treatment of BECs only partially suppressed IP-10 and TNF-alpha but was more effective at suppressing RANTES, IL-6, and IL-8. In acute clinical asthma serum IP-10 levels were increased to a greater extent in those with acute virus-induced asthma (median of 604 pg/mL compared with 167 pg/mL in those with non-virus-induced acute asthma, P < .01). Increased serum IP-10 levels were predictive of virus-induced asthma (odds ratio, 44.3 [95% CI, 3.9-100.3]). Increased serum IP-10 levels were strongly associated with more severe airflow obstruction (r = -0.8; P < .01). CONCLUSIONS: IP-10 release is specific to acute virus-induced asthma. CLINICAL IMPLICATIONS: Measurement of serum IP-10 could be used to predict a viral trigger to acute asthma.     

Correlation between eicosanoids in bronchoalveolar lavage fluid and in exhaled breath condensate

Exhaled breath condensate (EBC) has been increasingly used as a new and non-invasive method to study airway inflammation. In this study we have compared the concentrations of lipid mediators in EBC with concentrations in bronchoalveolar lavage fluid (BALF). We included 37 patients undergoing bronchoscopy (12 sarcoidosis, 12 COPD, 6 lung cancer, 5 chronic cough, 1 Wegener's granulomatosis, 1 sclerodermia). Patients were not allowed to have exacerbation or any change in concomitant medication for at least 4 weeks prior to the study. In all patients, EBC was collected immediately prior to the bronchoscopy. The levels of cys-LTs, LTB_{4}, 8-isoprostane were significantly higher in BALF compared to EBC (p < 0.0001, p< 0.001, p< 0.0001 for cys-LTs, LTB4, 8-isoprostane respectively). Moreover, there was a strong positive correlation between both leukotriene B_{4} and 8-isoprostane in BALF and EBC (r=0.53 and r=0.79, p< 0.01, respectively) in patients with sarcoidosis and COPD but there was no correlation between eicosanoids BALF and EBC in patients with chronic cough and lung cancer. This is the first study to compare EBC and BALF in different lung diseases which demonstrated significant correlations between the levels of eicosanoids in BALF and EBC in patients with COPD and sarcoidosis. EBC may be useful in measuring inflammation in several inflammatory lung diseases.     

Effects of a leukotriene receptor antagonist on exhaled leukotriene E4 and prostanoids in children with asthma

BACKGROUND: Leukotriene (LT) E(4) and 8-isoprostane concentrations are elevated in exhaled breath condensate in children with asthma. The effects of leukotriene receptor antagonists (LTRAs) on exhaled leukotriene and prostanoids in children with asthma are unknown. OBJECTIVE: (1) To study the effect of montelukast, a LTRA, on exhaled LTE(4), 8-isoprostane, and prostaglandin E(2) in children with asthma and atopic children; (2) to measure exhaled nitric oxide. METHODS: An open-label study with oral montelukast (5 mg once daily for 4 weeks) was undertaken in 17 atopic children with asthma and 16 atopic children without asthma. RESULTS: Pretreatment exhaled LTE(4) (P < .0001) and 8-isoprostane (P < .0001) values were higher in atopic children with asthma than in atopic children without asthma. In atopic children with asthma, montelukast reduced exhaled LTE(4) by 33% (P < .001), and this reduction was correlated with pretreatment LTE(4) values (r = -0.90; P = .0001). Posttreatment exhaled LTE(4) levels in children with asthma were higher than pretreatment LTE(4) values in atopic children without asthma (P < .004). Montelukast had no effect on exhaled LTE(4) in atopic children without asthma (P = .74), or on exhaled 8-isoprostane (atopic children with asthma, P = .94; atopic children without asthma, P = .55) and PGE(2) (atopic children with asthma, P = .56; atopic children without asthma, P = .93) in both groups. In atopic children with asthma, exhaled nitric oxide concentrations were reduced by 27% (P < .05) after montelukast. CONCLUSION: Leukotriene receptor antagonists decrease exhaled LTE(4) in atopic children with asthma. This reduction is dependent on baseline exhaled LTE(4) values. CLINICAL IMPLICATIONS: Measurement of exhaled LTE(4) might help identify children with asthma most likely to benefit from LTRAs.     

Exhaled eicosanoids and biomarkers of oxidative stress in exacerbation of chronic obstructive pulmonary disease

Introduction

Eicosanoids and oxidants play an important role in inflammation, but their role in chronic obstructive pulmonary disease (COPD) is uncertain. In this study we hypothesized that levels of exhaled leukotrienes, prostaglandins and biomarkers of oxidative stress are increased in infectious exacerbations of COPD and that they decrease after antibiotic therapy.

Material and methods

Cysteinyl-leukotrienes (LTs), leukotriene B₄ (LTB₄), prostaglandin E₄, hydrogen peroxide (H₂O₂) and 8-isoprostane were measured in exhaled breath condensate (EBC) in 16 COPD patients with infectious exacerbations (mean age 64 ±12 years, 13 male) on day 1, during antibiotic therapy (days 2-4), 2-4 days after therapy and at a follow-up visit when stable (21-28 days after therapy).

Results

There was a significant fall in concentration of cys-LTs, LTB₄ and 8-isoprostane at visit 3 compared to day 1 (cys-LTs: 196.5 ±38.4 pg/ml vs. 50.1 ±8.2 pg/ml, p < 0.002; LTB₄: 153.6 ±25.5 pg/ml vs. 71.9 ±11.3 pg/ml, p < 0.05; 8-isoprostane: 121.4 ±14.6 pg/ml vs. 56.1 ±5.2 pg/ml, p < 0.03, respectively). Exhaled H₂O₂ was higher on day 1 compared to that at visits 2 and 3 (0.74 ±0.046 µM vs. 0.52 ±0.028 µM and 0.35 ±0.029 µM, p < 0.01 and p < 0.01, respectively). Exhaled PGE₂ levels did not change during exacerbations of COPD. Exhaled eicosanoids and H₂O₂ in EBC measured at the follow-up visit (stable COPD) were significantly higher compared to those from healthy subjects.

Conclusions

We conclude that eicosanoids and oxidants are increased in infectious exacerbations of COPD. They are also elevated in the airways of stable COPD patients compared to healthy subjects.     

Interleukin-4 and interleukin-4 soluble receptor alpha levels in bronchoalveolar lavage from children with asthma.

BACKGROUND: In asthma there is increased expression of the Th2-type cytokine interleukin-4 (IL-4). IL-4 is important in immunoglobulin isotype switching to immunoglobulin E and adhesion of eosinophils to endothelium. OBJECTIVE: We hypothesized that levels of IL-4 in bronchoalveolar lavage (BAL) fluid would be increased in stable, atopic asthmatic children compared with controls and that levels of its physiologic inhibitor IL-4 soluble receptor alpha (IL-4sR alpha) would be correspondingly decreased. METHODS: One hundred sixteen children attending a children's hospital for elective surgery were recruited. A nonbronchoscopic BAL was performed, and IL-4 and IL-4sR alpha were measured in the BAL supernatants. RESULTS: There was no significant difference in IL-4 concentrations between atopic asthmatic children, atopic normal controls, and nonatopic normal controls [0.13 pg/mL (0.13 to 0.87) vs 0.13 pg/mL (0.13 to 0.41) vs 0.13 pg/mL (0.13 to 0.5), P = 0.65]. IL-4sR alpha levels were significantly increased in asthmatic patients compared with atopic controls [6.4 pg/mL (5.0 to 25.5) vs 5.0 pg/mL (5.0 to 9.9), P = 0.018], but not when compared with the nonatopic controls [5.2 pg/mL (5.0 to 10.6), P = 0.19]. CONCLUSIONS: Contrary to expectation, IL-4sR alpha levels are increased in BAL from stable asthmatic children compared with nonatopic controls, and we speculate that IL-4sR alpha is released by inflammatory cells in the airways to limit the proinflammatory effects of IL-4.     

Exhaled breath condensate levels of eotaxin and macrophage-derived chemokine in stable adult asthma patients

Background Asthma is associated with esoinophilic airway inflammation and overproduction of T‐helper type 2 (Th2) lymphocyte‐related cytokines. Objective This study assessed the eosinophil chemoattractant eotaxin and Th2‐specific macrophage‐derived chemokine (MDC) in the adult asthmatic airway. Eotaxin and MDC levels were determined in exhaled breath condensate (EBC) obtained from adult patients with asthma. Methods Fifty‐four asthmatics (20 male, mean (SD) age 40 (12) years and percentage predicted forced expiratory volume in 1 s (FEV₁) 81.7 (20.8)) and 20 age‐ and sex‐matched controls were studied. EBC was collected using EcoScreen by 10 min of tidal breathing with a nose clip. Concentrations of eotaxin and MDC were measured by ELISA. Results Asthma patients on inhaled corticosteroid (ICS) had a higher median interquartile range (IQR) level of eotaxin than the steroid‐naïve asthmatics (18.5 (17.7–20.1) vs. 17.9 (17.0–18.6) pg/mL, P=0.02) and controls (18.5 (17.7–20.1) pg/mL vs 17.4 (16.3–18.0) pg/mL, P=0.001). Eotaxin level in EBC had a significant negative correlation with the FEV₁/forced vital capacity ratio (r=?0.43, P=0.03) in steroid‐naïve asthmatics. EBC MDC level was higher in subjects on ICS than the steroid naïve asthmatics (120 (118–125) vs. 117 (116–119) pg/mL, P=0.01) and the controls (120 (118–125) vs. 117 (116–120) pg/mL, P=0.02). Conclusions Eotaxin and MDC could be measured in EBC of adults with asthma. EBC eotaxin and MDC levels were higher in asthmatics on ICS than the steroid‐naïve asthmatics or controls. Exhaled chemokines may be potential non‐invasive markers for assessing airway inflammation in asthmatics.     

Leptin: does it have any role in childhood asthma?

BACKGROUND: Although there is evidence of a positive association between asthma and obesity in adults and children, very little is known about the role of leptin in asthmatic children. OBJECTIVES: The aims of this study were to evaluate the relation between leptin and parameters of atopy and asthma in children. METHODS: Body mass index (BMI) and serum leptin levels were measured in 102 (37 female, 65 male; mean age, 5.9 +/- 3.4 years) asthmatic and 33 (14 female, 19 male; mean age, 6.1 +/- 3.4 years) healthy children. Skin prick tests, total serum IgE, and pulmonary function tests were performed and were completed. RESULTS: A significant difference was observed in serum leptin levels between asthmatic and healthy children. Median (interquartile range) levels were 3.53 (2.06-7.24) ng/mL and 2.26 (1.26-4.71) ng/mL, respectively (P=.008). Subgroup analysis revealed that this difference in leptin levels was confined entirely to boys: 3.09 (1.99-7.51) ng/mL in boys with asthma versus 1.52 (1.06-3.17) ng/mL in boys without asthma (P=.003). By logistic regression analysis, we found that leptin was a predictive factor for having asthma (odds ratio, 1.98; CI, 1.10-3.55; P=.021), whereas sex, age, or BMI were not. In a stepwise multiple regression analysis including sex (P=.001), age (P=.016), BMI (P <.001), and asthma (P=.022), all of these variables were found to affect log leptin levels (R2=0.404). There was no significant sex difference in serum leptin levels among asthmatic children, whereas healthy boys had significantly lower leptin levels than healthy girls (P=.019). Atopic asthmatic subjects had significantly higher leptin levels than nonatopic asthmatic subjects (P=.038) with similar BMI. A significant, but weak, correlation was observed between leptin levels and IgE in the overall group of asthmatic children (r=0.231; P=.019). Again, this correlation was confined entirely to boys (r=0.319; P=.010). There was no relation between leptin levels and skin prick tests, pulmonary function tests, passive smoking, birth weight, and duration of breast-feeding. CONCLUSION: Our findings suggest that leptin may play a role in atopic asthma. High serum leptin levels in asthmatic boys may partly explain the higher prevalence of childhood asthma in male sex.     

Proliferation and activation of bronchial epithelial cells in corticosteroid-dependent asthma.

BACKGROUND: Structural and functional characteristics of bronchial epithelial cells in corticosteroid-dependent asthma are unknown. OBJECTIVE: In bronchial biopsy specimens from 16 control, 9 untreated asthmatic, 9 inhaled corticosteroid-treated asthmatic, and 19 corticosteroid-dependent asthmatic subjects, we evaluated epithelium morphology and patterns of cell apoptosis, proliferation, and activation. METHODS: We used the terminal deoxynucleotidyl-mediated dUTP nick end labeling (TUNEL) technique to study apoptosis. Immunohistochemistry was used to evaluate the expression of molecules related to apoptosis (such as Bcl-2 and P53), cell proliferation (PCNA), and cell activation (NFkappaB and CD40/CD40-L). RESULTS: Epithelium thickness was higher in corticosteroid-dependent asthmatic and control subjects than in inhaled corticosteroid-treated and untreated asthmatic subjects (P < .0001 and P <.0003). Very few TUNEL-positive epithelial cells were found in the 4 groups. Bcl-2 expression was higher in all groups of asthmatic subjects than in controls (P < .001). In corticosteroid-dependent asthmatic subjects, PCNA, NFkappaB, and CD40-L expression was higher than in inhaled corticosteroid-treated asthmatic (P < .001), untreated asthmatic (P <.001 and P < .04), and control (P < .01) subjects. CD40 expression was greater in corticosteroid-dependent asthmatic and untreated asthmatic subjects than in inhaled corticosteroid-treated asthmatic subjects (P < .0001 and P < .0006) and controls (P < .02 and P < .03). In corticosteroid-dependent asthma, PCNA expression was correlated with the epithelium thickness (P < .007). CONCLUSION: This study shows that in bronchial epithelial cells of corticosteroid-dependent asthma, markers of cell survival and proliferation are coexpressed with markers of cell activation, suggesting that in this disease epithelium repair is associated with a persistent activation state of epithelial cells.     

A randomized, double-blind trial of the effect of treatment with montelukast on bronchial hyperresponsiveness and serum eosinophilic cationic protein (ECP), soluble interleukin 2 receptor (sIL-2R), IL-4, and soluble intercellular adhesion molecule 1 (sICAM-1) in children with asthma

BACKGROUND: Anti-inflammatory properties of leukotriene modifiers and their effect on bronchial hyperresponsiveness have not been studied in children with asthma. OBJECTIVE: The primary objective of this study was to determine the changes in serum levels of inflammatory mediators, clinical efficacy, and bronchial hyperresponsiveness after treatment with montelukast. METHODS: In this double-blind, randomized, placebo-controlled trial, 39 children with mild-to-moderate atopic asthma were randomly allocated to receive montelukast or placebo for 6 weeks. Main outcome measures were changes in serum concentrations of soluble interleukin 2 receptor (sIL-2R), IL-4, and soluble intercellular adhesion molecule 1 (sICAM-1); peripheral blood eosinophil count; and eosinophilic cationic protein (ECP). Asthma severity score, FEV(1), and bronchial hyperreactivity (BHR) for histamine were secondary end points. RESULTS: Compared to placebo, serum concentrations of IL-4, sICAM-1, and ECP and eosinophil blood counts significantly decreased after 6 weeks of treatment with montelukast. Montelukast significantly improved asthma control and FEV(1). Montelukast resulted in within-group significant decrease in levels of serum sIL-2R (611 vs. 483 pg/mL), IL-4 (0.123 vs 0.102 pg/mL), sICAM-1 (280 vs. 244 ng/mL), and ECP (74 vs. 59 microg/mL) and in eosinophil blood counts (349 vs. 310 cells/mm(3)). Mean FEV(1) value changed from 85% of predicted to 95% (P <.001) and for histamine (PC(20)H) from 2.8 mg/mL to 3.8 mg/mL (P <.001) after treatment with montelukast. There was no significant difference between montelukast and placebo recipients in the serum concentrations of sIL-2R and PC(20)H after treatment. CONCLUSION: Montelukast provides clinical benefit to patients with chronic asthma and decreases bronchial hyperresponsiveness. Montelukast caused a statistically significant decrease of serum concentrations in cytokine, ICAM-1, and ECP and peripheral blood eosinophil counts over the 6-week treatment period. This observation raises the possibility that leukotriene receptor antagonists, such as montelukast, may have effects on parameters of asthmatic inflammation.