Mediators In Exhaled Breath Condensate Research Articles

Physical Training Reduces Chronic Airway Inflammation and Mediators of Remodeling in Asthma.

Several benefits of aerobic training for asthmatic patients have been demonstrated. However, its effects on systemic inflammation and on airway remodeling mediators and lung mechanics are unknown. This prospective study included 21 intermittent and mild asthma patients, and as primary outcomes, the evaluation of pro- and anti-inflammatory and pro- and antifibrotic mediators in exhaled breath condensate (EBC) and blood were performed, beyond the cell counting in blood and in induced sputum. Aerobic training was performed for 3 months, 3 times per week. Aerobic training increased the levels of anti-inflammatory cytokines and of antifibrotic mediators in the breath condensate: IL-1ra (p = 0.0488), IL-10 (p = 0.0048), relaxin-3 (p = 0.0019), and klotho (p < 0.0043), respectively. Similarly, in plasma, increased levels of IL-1ra (p = 0.0147), IL-10 (p < 0.0001), relaxin-3 (p = 0.004), and klotho (p = 0.0023) were found. On contrary, reduced levels of proinflammatory cytokines in the breath condensate, IL-1β (p = 0.0008), IL-4 (p = 0.0481), IL-5 (p < 0.0001), IL-6 (p = 0.0032), IL-13 (p = 0.0013), and TNF-α (p = 0.0001) and profibrotic markers VEGF (p = 0.0017) and TSLP (p = 0.0056) were found. Similarly, in plasma, aerobic training significantly reduced the levels of proinflammatory cytokines IL-1β (p = 0.0008), IL-4 (p = 0.0104), IL-5 (p = 0.0001), IL-6 (p = 0.006), IL-13 (p = 0.0341), and TNF-α (p = 0.0003) and of profibrotic markers VEGF (p = 0.0009) and TSLP (p < 0.0076). Fractional exhaled nitric oxide (FeNO) was reduced after the intervention (p = 0.0313). Regarding inflammatory cells in sputum, there was a reduction in total cells (p = 0.008), eosinophils (p = 0.009), and macrophages (p = 0.020), as well as of blood eosinophils (p = 0.0203) and lymphocytes (p = 0.0198). Aerobic training positively modulates chronic airway inflammation and remodeling mediators, beyond to improve systemic inflammation in intermittent and mild asthmatic patients.

Oxidative Stress and Inflammatory Mediators in Exhaled Breath Condensate of Patients with Pulmonary Tuberculosis. A Pilot Study with a Biomarker Perspective.

Tuberculosis (TB) is one of the highest infectious burdens worldwide. An excess of inflammation and inadequate antioxidant defense mechanisms are believed to lead to chronic inflammation and lung damage in tuberculosis (TB). However, circulating metabolites do not always replicate lung-associated biomarkers that define the pathobiology of the disease. The objective of this study was to determine the utility of exhaled breath condensate (EBC), a non-invasive and straightforward sample, to evaluate alveolar space-derived metabolites of redox state and inflammation. We assessed the levels of exhaled oxidant/antioxidant parameters (8-isoprostane, MDA, GSH), inflammatory markers, such as nucleosomes, cytokines (IL-2, IL-4, IL-6 and IL-8, IL-10, GM-CSF, TNF-α, and IFN-γ) and lipid mediators (PGE2, LTB4, RvD1, and Mar1), in patients with recently diagnosed pulmonary TB and healthy controls’ EBC and serum. The TB patients showed 36% lower GSH levels, and 2-, 1.4-, 1.1-, and 50-fold higher levels of 8-isoprostanes, nucleosomes, IL-6, and LTB4, respectively, in EBC. There was no correlation between EBC and serum, highlighting the importance of measuring local biomarkers. Quantitation of local inflammatory molecules and redox states in EBC would help find biomarkers useful for pharmacological and follow-up studies in pulmonary tuberculosis.

Changes in the concentrations of mediators in exhaled breath condensate during cardiac valve replacement under cardiopulmonary bypass and their relations with postoperative acute respiratory distress syndrome.

To investigate the changes in the concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and 8-iso-prostaglandin F2α (8-isoPGF2α) in exhaled breath condensate (EBC) in patients undergoing cardiac valve replacement under cardiopulmonary bypass (CPB) and its relationship with postoperative acute respiratory distress syndrome (ARDS).A prospective, case–control study was performed on 55 patients undergoing elective cardiac valve replacement under cardiopulmonary bypass, between November 2017 and May 2019. According to the diagnosis of postoperative ARDS, the patients were divided into ARDS group and control group. We compared the clinical characteristics, outcomes, respiratory mechanics, oxygenation parameters, and mediators in the 2 groups immediately after tracheal intubation (T1), at the end of CPB (T2), and 2 hours (T3) and 6 hours (T4) after CPB, and calculated the receiver operating characteristic curve (ROC), sensitivity, and specificity of the corresponding mediators.ARDS occurred in 29 patients after CPB. The ARDS group exhibited prolonged postoperative ventilator support, time to extubation, length of stay in the ICU, and postoperative length of stay. The peak airway pressure (Ppeak) and plat airway pressure (Pplat) at T4 were higher in the ARDS group compared with the control group. The alveolar-arterial oxygen partial pressure [P(A-a)O2] and respiratory index (RI) were higher and PaO2/FiO2 was lower in the ARDS group at T2–4 compared with the control group. The levels of EBC and serum mediators in the ARDS group were significantly higher at T2–4 compared with those in the control group. All the mediators in EBC were correlated significantly with those in the serum in the ARDS group (r = 0.7314, 0.898, 0.8386, 0.792) and control group (r = 0.6093, 0.8524, r = 0.7828, r = 0.6575) (P < .001). Meanwhile, the area under the curve (AUC) of IL-8 in EBC was significantly lower at T2 and the AUC of IL-6 in EBC was significantly higher at T4 than in serum (P < .05). In addition, all of the mediators in EBC had a certain accuracy in diagnose of postoperative ARDS.EBC analysis could be used to predict the high incidence of ARDS after cardiac valve replacement under CPB.

Inflammatory mediators in exhaled breath condensate and peripheral blood of healthy donors and stable COPD patients

Objective: The aim of this work was to compare matrix metalloproteinase-9 and -12, tissue inhibitor of metalloproteinase-1 and -4, and neutrophil elastase in exhaled breath condensate (EBC) and peripheral blood of patients with COPD.Methods: Peripheral blood and EBC samples from COPD patients and healthy donors were collected. In serum and EBC, MMP-9, MMP-12, NE, TIMP-1, and TIMP-4 proteins were detected by ELISA. The mRNA expression levels of MMP-9, MMP-12, NE, TIMP-1, and TIMP-4 in peripheral blood mononuclear cells (PBMCs) were analyzed by qRT-PCR.Results: The protein levels of MMP-9 (p=.034) and MMP-12 (p=.041) in the EBC of COPD smokers were higher than those of COPD never-smokers. The concentrations of TIMP-1 (p=.072) and TIMP-4 (p=.084) in the EBC of COPD smokers were higher than those of COPD never-smokers; however, the difference was not statistically significant. MMP-9 (r=–0.78, p<.0001) and TIMP-1 (r=–0.71, p<.0001) levels in EBC were significantly negatively correlated with pulmonary function FEV1%pred. The protein levels of MMP-12 (r=–0.37, p=.034) and TIMP-4 (r=–0.34, p=.041) were also negatively correlated with FEV1%pred. The expression of MMP-9, MMP-12, NE, TIMP-1, and TIMP-4 in PBMCs and serum of COPD smokers were significantly higher than those of control never-smokers (p<.05).Conclusions: Exhaled MMP-9, MMP-12, TIMP-1, and TIMP-4 levels increased in stable COPD patients and were negatively correlated with FEV1%pred, which suggests the usefulness of their measurement in EBC for the monitoring of airway inflammation. However, to better assess their diagnostic or prognostic value, larger studies are necessary.

Resolvins attenuate inflammation and promote resolution in cigarette smoke-exposed human macrophages.

Inflammation is a protective response to injury, but it can become chronic, leading to tissue damage and disease. Cigarette smoke causes multiple inflammatory diseases, which account for thousands of deaths and cost billions of dollars annually. Cigarette smoke disrupts the function of immune cells, such as macrophages, by prolonging inflammatory signaling, promoting oxidative stress, and impairing phagocytosis, contributing to increased incidence of infections. Recently, new families of lipid-derived mediators, "specialized proresolving mediators" (SPMs), were identified. SPMs play a critical role in the active resolution of inflammation by counterregulating proinflammatory signaling and promoting resolution pathways. We have identified dysregulated concentrations of lipid mediators in exhaled breath condensate, bronchoalveolar lavage fluid, and serum from patients with chronic obstructive pulmonary disease (COPD). In human alveolar macrophages from COPD and non-COPD patients, D-series resolvins decreased inflammatory cytokines and enhanced phagocytosis. To further investigate the actions of resolvins on human cells, macrophages were differentiated from human blood monocytes and treated with D-series resolvins and then exposed to cigarette smoke extract. Resolvins significantly suppressed macrophage production of proinflammatory cytokines, enzymes, and lipid mediators. Resolvins also increased anti-inflammatory cytokines, promoted an M2 macrophage phenotype, and restored cigarette smoke-induced defects in phagocytosis, highlighting the proresolving functions of these molecules. These actions were receptor-dependent and involved modulation of canonical and noncanonical NF-κB expression, with the first evidence for SPM action on alternative NF-κB signaling. These data show that resolvins act on human macrophages to attenuate cigarette smoke-induced inflammatory effects through proresolving mechanisms and provide new evidence of the therapeutic potential of SPMs.

Changes in the Concentrations of Mediators of Inflammation and Oxidative Stress in Exhaled Breath Condensate During Liver Transplantation and Their Relations With Postoperative ARDS.

Oxidative stress and inflammatory responses are thought to be involved in the pathogenesis of ARDS, which is one of the most serious complications of orthotopic liver transplantation (OLT). The collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining clinical samples from the lungs. However, the changes of mediators of inflammation and oxidative stress in EBC remain unclear. Therefore, the aim of this study was to investigate the changes of mediators in EBC from OLT subjects and the relations between these mediators and ARDS. The levels of mediators of oxidative stress (superoxide dismutase [SOD], malondialdehyde [MDA], H2O2, NO, and 8-iso-prostaglandin F2α) and of inflammatory factors (tumor necrosis factor-α[TNF-α], interleukin [IL]-8, and IL-10) were measured in EBC and serum samples collected from 28 subjects before OLT surgery and at 2 and 4 h after the anhepatic phase. The diagnostic value for ARDS until the 3 days following transplantation was evaluated. Eighteen subjects developed ARDS after OLT. The concentrations of TNF-α, IL-8, MDA, NO, H2O2, and 8-iso-prostaglandin F2α were much higher in the ARDS group than in the control group, whereas the levels of IL-10 and SOD were lower in the ARDS group than in the control group. The serum levels of mediators of oxidative stress or inflammation were closely related to EBC levels. Receiver operating characteristic analysis showed that areas under the curves for MDA, NO, H2O2, 8-iso-prostaglandin F2α, TNF-α, IL-8, SOD, and IL-10 were 0.88, 0.88, 0.78, 0.84, 0.84, 0.94, 0.81, and 0.84 at 2 h after graft reperfusion and 0.98, 0.88, 0.92, 0.79, 0.95, 0.83, 0.88, and 0.97 at 4 h after graft reperfusion. EBC analysis is a noninvasive method for detecting mediators of inflammation and oxidative stress from the lungs. This method could be used to predict the higher incidence of ARDS induced by OLT.

S64 Eosinophil Cationic Protein And Cytokine Analysis In Exhaled Breath Condensate In Paediatric Asthma

Background Sputum eosinophil counts are unstable in childhood asthma.1 This makes sputum induction to quantify sputum eosinophils an unsuitable test to guide anti-inflammatory therapy.2 While eosinophils may be cleared following apoptosis, free eosinophil granules, containing effector proteins, may persist in the airway lumen. We speculated that inflammatory mediators in exhaled breath condensate, released by eosinophils (such as eosinophil cationic protein (ECP)) could aid risk-profiling in children with asthma. We therefore sought to assess whether ECP is present in EBC from asthmatic children, alongside an assessment of pro-inflammatory cytokines. Methods Children with asthma aged 7–15 and age matched healthy controls underwent spirometry, sputum induction, collection exhaled breath condensate (EBC), and completed the childhood asthma control test. Exhaled breath was tested for eosinophil cationic protein (ECP) using an immunoassay. A cytokine analysis of the exhaled breath condensate was also carried out in addition to a sputum leucocyte differential. Exhaled breath condensate (EBC) was collected in an R-tube following manufacturer protocol,over 10 min. Results Sputum leucocyte counts were performed in 33 children with asthma. Suitable samples (visible airway plugs) were obtained from 14 children at baseline who concurrently provided EBC samples. Of these, 7/14 (50%) were eosinophilic and 7/14 (50%) were non-eosinophilic. The cytokine analysis showed that IL-4 did not differ between groups. IL-13 was raised in children who had sputum eosinophilia (2.54 ± 1.18 vs. 0.87 ± 1.49 pg/ml, mean±sd, p = 0.0387, unpaired t-test). Exhaled breath condensate was collected in 26 asthmatic children and 10 controls. ECP was detected in EBC from 5/26 asthmatic children and 0/10 healthy children. In 2 asthmatic children, detectable ECP was associated with sputum eosinophilia (>2.5%). In one child ECP was detectable with no induced sputum eosinophils. ([Table 1][1]). Discussion ECP may be identified in EBC from children with asthma, and is not exclusively associated with concurrent sputum eosinophilia. Eosinophilia may be identified non-invasively by measuring Th2 cytokines in EBC. These techniques may provide additional insights into underlying airway inflammation and identify children who may benefit from specific anti-Th2 cytokine monoclonal antibody therapies.

Assessment of the inflammatory effect of low-dose oxygen in mechanically ventilated patients

Although low doses of oxygen (FiO2 <0.50) are considered nontoxic, recent studies have shown that even lower doses increase pulmonary inflammatory mediators. We aimed to evaluate the acute effects of reducing FiO2 on pulmonary inflammation in mechanically ventilated patients without respiratory failure. This study was a prospective, single-center crossover study in a medical/surgical intensive care unit at a university hospital. Hemodynamically stable patients under mechanical ventilation for >24 h without severe respiratory failure (PaO2/FiO2 >250). A basal FiO2 of 0.40 was reduced to 0.21 provided SpO2 remained higher than 90 %. Patients who could not tolerate the reduction in FiO2 to 0.21 were excluded. We screened 40 patients, but only 28 (70 %) tolerated FiO2 0.21. We measured common clinical variables and inflammatory mediators in plasma and in exhaled breath condensate (EBC) at the end of three 4-h periods: (1) basal (FiO2 0.40), (2) after FiO2 reduction to 0.21, and (3) after returning FiO2 0.40. We used one-way ANOVA for repeated measurements with FiO2 as the grouping variable. Median values of inflammatory mediators in EBC showed nonsignificant changes among the three periods: NO2 + NO3 17.1, 14.1 and 11.0 μmol/L (p = 0.2), and 8-isoprostane 4.4, 8.2 and 5.3 pg/ml (p = 0.6) for the three periods, respectively. Plasma levels also showed nonsignificant changes during the period of the study: NO2 + NO3 12.6, 16.3 and 15.0 μmol/L (p = 0.9), TNFα 13.5, 18.0 and 14.5 pg/ml (p = 0.8), IL-4 12.9, 18.7 and 23.9 pg/ml (p = 0.1), IL-6 50.9, 35.1 and 28.3 pg/ml (p = 0.6), and IL-10 15.2, 22.2 and 22.2 pg/ml (p = 0.7) for the three periods, respectively. FiO2 0.40 in mechanically ventilated patients without severe respiratory failure did not increase systemic or pulmonary inflammation.

Inflammatory mediators in exhaled breath condensate of healthy donors and exacerbated COPD patients

Samples of exhaled breath condensate (EBC) provide a convenient and non-invasive method to study inflammation in lung diseases. The aim of the present study was to evaluate and compare the inflammatory protein mediator levels in EBC from healthy donors (HD) and from patients with exacerbation of chronic obstructive pulmonary disease (COPD) using an EBC collection device with and without a coating of albumin as a carrier. We studied 13 HD and 26 patients with exacerbation of COPD. The concentrations of myeloperoxidase (MPO), IFNγ and secretory leukocyte protease inhibitor (SLPI) in EBC were measured by immunoassays. The EBC samples from HD and COPD patients showed higher concentrations of MPO when samples were recovered with an albumin-coated device. Furthermore, levels of MPO in COPD patients were significantly higher than in HD. An inverse correlation was observed between MPO and spirometric parameters (FVC and FEV1). Almost all samples collected with the albumin-coated device showed higher amounts of IFNγ and SLPI than those collected with the uncoated device. The levels of SLPI in COPD patients were significantly higher than in HD. A direct correlation was observed between FVC% predicted and SLPI.We concluded that coating the collection device with albumin increased the sensitivity of the technique, at least for measurements of MPO, SLPI and IFNγ. Furthermore, the higher levels of MPO and SLPI and lower levels of IFNγ in EBC from COPD patients could reflect the immunological status and the response of lung parenchyma to treatment during the exacerbation of the illness.

Mediators in Exhaled Breath Condensate after Hypertonic Saline Challenge

Background. Airway narrowing after hypertonic saline challenge (HSC) is postulated to be mediated by bronchoconstrictors and inflammatory mediators. Objective. To study the mechanism of this challenge by using exhaled breath condensate (EBC). Methods. Fifty-six subjects (9 to 72 years of age) performed an HSC, with EBC collection and exhaled nitric oxide (FENO) measurements before and after the challenge. Bronchial hyper-reactivity (BHR) was defined if forced expiratory volume in 1 second (FEV1) decreased by 10% compared with baseline (PD10). EBC volume was recorded and was analyzed for mucin, histamine, nitrite/nitrate, and pH. Results. Those with BHR had a significant rise in EBC volume/5-minute collection period after challenge (286.3 ± 25.6 μl vs 402.2 ± 31.3 μl, p = 0.0002), while BHR(−) subjects did not show this change (387.6 ± 29.7 μl vs 364.1 ± 30.1 μl, p = 0.55). FENO showed a significant decrease in both BHR(+) and BHR(−) groups after challenge (p = < 0.0001). In BHR(+) subjects histamine increased significantly (1.3 ± 0.1 μM vs 1.5 ± 0.1 μM, p = 0.006) compared with baseline, while EBC pH and mucin increased significantly after HSC in both groups. EBC nitrite did not change in either group. Conclusion. EBC analysis suggests that HSC causes an increase in pH and mucin in both groups, but EBC volume and histamine only increased in the BHR(+) group. This suggests that mast cells are activated and fluid flux is associated with the positive response, while mucin release is independent of BHR in HSC.

Exhaled cysteinyl-leukotrienes and 8-isoprostane in patients with asthma and their relation to clinical severity

Collection of exhaled breath condensate (EBC) is a safe, non-invasive method to collect droplets of the airway surface liquid and measure mediators of airway inflammation and oxidative stress, such as cysteinyl-leukotrienes (cys-LTs) and 8-isoprostane. The aim of our study was to investigate baseline values of inflammatory lipid mediators in EBC and their relation to asthma severity. Nineteen healthy subjects, 16 mild, 12 moderate and 15 severe asthmatics were studied. All subjects attended a clinic visit for spirometry and EBC collection. The concentrations of exhaled cys-LTs and 8-isoprostane were measured by means of specific enzyme immunoassays. 8-isoprostane levels were significantly increased in mild (49.1+/-5.2 pg/mL, p<0.001), moderate (49.7+/-5.2 pg/mL, p<0.001) and severe asthmatics (77.7+/-7.3 pg/mL, p<0.001), compared to healthy controls (16.4+/-1.6 pg/mL). Moreover, 8-isoprostane levels were significantly higher in severe compared to mild and moderate asthmatics (p<0.01). Cys-LT levels were significantly higher in moderate (34.6+/-4.4 pg/mL, p<0.05) and severe asthmatics (47.9+/-6.0 pg/mL, p<0.001), while no significant difference was found between healthy controls and mild asthmatics. 8-isoprostane levels in EBC of asthmatics strongly correlated with cys-LT levels (r=0.61, p<0.0001). 8-isoprostane and cys-LT are detectable in EBC of healthy subjects and their levels progressively increase in asthmatic patients according to disease severity. The correlation found between these two lipid mediators indicating a link between oxidative stress and airway inflammation.

Validation of assays for inflammatory mediators in exhaled breath condensate

The use of exhaled breath condensate (EBC) as a tool for noninvasive assessment of lung inflammation is becoming commonplace. Many authors use commercial ELISA kits to measure inflammatory mediators within EBC. However, the very low concentrations of mediators within EBC are often below the commercially validated concentration range of the relevant ELISA and crucially below the linear part of the sigmoid standard curve. The present study seeks to validate a series of assays for use in EBC and to compare the results in EBC with those from matched sol phase sputum samples. The following mediators were measured by ELISA: leukotriene (LT)B(4), interleukin (IL)-8, secretory leukoprotease inhibitor and alpha(1)-antitrypsin (AAT). Myeloperoxidase was measured by chromogenic substrate assay. Mediator concentrations reached the lower limit of quantification in only one assay (AAT) in 19.6% of subjects, while mediator concentrations reached the lower limit of detection in three assays (LTB(4), IL-8 and AAT in 31, 6.5 and 61% of subjects, respectively). No significant correlations were present between any mediators in EBC and sol phase sputum. The results of the present study indicate that care must be exercised when interpreting mediator measurements in exhaled breath condensate and that assays must be validated at concentrations relevant to those found within the biological fluid.

Review: Analysis of exhaled breath condensate in respiratory medicine: methodological aspects and potential clinical applications

Analysis of exhaled breath condensate (EBC) is a noninvasive method for studying the composition of airway lining fluid and has the potential for assessing lung inflammation. EBC is mainly formed by water vapor, but also contains aerosol particles in which several biomolecules including leukotrienes, 8-isoprostane, prostaglandins, hydrogen peroxide, nitric oxide-derived products, and hydrogen ions, have been detected in healthy subjects. Inflammatory mediators in EBC are detected in healthy subjects and some of them are elevated in patients with different lung diseases. Analysis of EBC is completely noninvasive, is particularly suitable for longitudinal studies, and is potentially useful for assessing the response to pharmacological therapy. Identification of selective profiles of biomarkers of lung diseases might also have a diagnostic value. However, EBC analysis currently has important limitations. The lack of standardized procedures for EBC analysis and validation of some analytical techniques makes it difficult comparison of results from different laboratories. Analysis of EBC is currently more useful for relative measures than for quantitative assessment of inflammatory mediators. Reference analytical techniques are required to provide definitive evidence for the presence of some inflammatory mediators in EBC and for their accurate quantitative assessment in this biological fluid. Several methodological issues need to be addressed before EBC analysis can be considered for clinical applications. However, further research in this area is warranted due to the relative lack of noninvasive methods for assessing lung inflammation.

Eicosanoids in Exhaled Breath Condensate and BAL Fluid of Patients With Sarcoidosis

Measurement of inflammatory mediators in exhaled breath condensate (EBC) is an easy and noninvasive diagnostic method, which has gained popularity in the past few years. However, the source of these mediators is not precisely defined. It has been only presumed that inflammatory cells present in the airway lumen are the main source. Therefore, the aim of this study was to verify the relationship between EBC and BAL fluid (BALF) eicosanoids, and the percentage, number, and activity of cells in BALF. In 28 sarcoidosis patients and 17 healthy subjects, 8-isoprostane, cysteinyl leukotrienes (CysLTs), and leukotriene B4 (LTB4) were measured in EBC by enzyme immunoassay. Eicosanoids were also examined in BALF in the study group. Cell count, percentage, and superoxide production by BALF cells were estimated. The mean (+/- SEM) CysLT and 8-isoprostane concentrations were higher in the sarcoidosis group (6.5 +/- 0 vs 27.82 +/- 6.65 pg/mL, respectively; and 2.67 +/- 0.16 vs 13.95 +/- 2.59 pg/mL, respectively). There were positive correlations between EBC and BALF 8-isoprostane concentration (r = 0.68, p < 0.0001) and LTB4 concentration (r = 0.43; p = 0.026). EBC LTB4 levels correlated with the number of lymphocytes per milliliter of BALF. The percentage and number of eosinophils in BALF correlated with EBC 8-isoprostane and BALF CysLT concentrations. No positive correlation was found between concentrations of EBC eicosanoids and percentages BALF lymphocytes, BALF macrophages, or superoxide production. The levels of 8-isoprostane and CysLT are elevated in EBC in sarcoidosis patients; however, a lack of correlation with BALF lymphocyte percentage does not encourage us to recommend the measurement of eicosanoids as activity markers. The positive correlation of EBC 8-isoprostane and BALF CysLT concentrations with the percentage of eosinophils in BALF, and the higher percentage of eosinophils in BALF from patients with grade 3 sarcoidosis, may suggest the possible prognostic value.

Inflammatory Mediators in Exhaled Breath Condensate of Children With Obstructive Sleep Apnea Syndrome

Upper airway inflammation is now recognized in adults with obstructive sleep apnea (OSA) syndrome. However, the role played by eicosanoids such as leukotrienes and prostaglandins is unclear. To investigate whether eicosanoids are measurable in exhaled breath condensate (EBC), and to determine whether differences in these inflammatory mediators emerge among children with and without sleep-disordered breathing (SDB). EBC was collected from 50 consecutive snoring children undergoing overnight polysomnography for suspected SDB, and from 12 nonsnoring control subjects. Prostaglandin E2 (PGE2), leukotriene B4 (LTB4), and cysteinyl leukotrienes (cys-LTs: leukotriene C4 [LTC4]/leukotriene D4 [LTD4]/leukotriene E4 [LTE4]) EBC levels were analyzed using enzyme-linked immunosorbent assay. LTB4 levels were elevated in children with an apnea-hypopnea index (AHI) > 5/h (SDB; 97.6 +/- 6.3 pg/mL) compared to children with an AHI < 5/h (mild SDB; 66.4 +/- 19.1 pg/mL; p < 0.01) and control subjects (27.8 +/- 3.7 pg/mL; p < 0.01). Similarly, cys-LT (LTC4/LTD4/LTE4) concentrations were also increased in SDB (45.1 +/- 10.6 pg/mL in SDB vs 27.6 +/- 8.3 pg/mL in mild SDB, and 15.7 +/- 7.6 pg/mL in control subjects; p < 0.01). In contrast, PGE2 concentrations were similar among the three groups. Inflammatory mediators such as leukotrienes and prostaglandins can be readily quantified in EBC collected from the upper airway of children. Disease severity-dependent increases in leukotriene concentrations (LTB4 and LTC4/LTD4/LTE4) emerge among children and may serve as a noninvasive tool in the clinical assessment of these children.

Cytokines in exhaled breath condensate of children with asthma and cystic fibrosis

Inflammatory mediators in exhaled breath condensate (EBC) indicate ongoing inflammation in the lungs and might differentiate between asthma and cystic fibrosis (CF). To evaluate the presence, concentration, and short-term variability of TH1- and TH2-mediated cytokines (interferon-gamma [IFN-gamma], tumor necrosis factor alpha [TNF-alpha], interleukin 10 [IL-10], IL-5, IL-4, and IL-2) in EBC of children with asthma or CF and in controls and to analyze the discriminating ability of inflammatory markers in EBC between children with asthma or CF and controls. Expired air was conducted through a double-jacketed glass tube cooled by circulating ice water. In 33 asthmatic children, 12 children with CF, and 35 control children, EBC was collected during tidal breathing. Cytokines were measured using flow cytometry. Interleukin 2, IL-4, IFN-gamma, and IL-10 were detected in 16%, 16%, 11%, and 9%, respectively, of all samples in asthma and CF. Interleukin 5 and TNF-alpha were not detected in children with CF. Cytokine concentrations did not differ significantly in children with asthma vs CF. In controls, IFN-gamma, TNF-alpha, and IL-10 were detected in 9%, 14%, and 3%, respectively; IL-2, IL-4, and IL-5 were not detected in controls. Cytokines such as IFN-gamma, TNF-alpha, IL-10, IL-5, IL-4, and IL-2 can be detected in EBC of children with asthma or CF. However, the concentrations found are close to the detection limits of the assay used. These findings emphasize the importance of developing more sensitive techniques for the analysis of EBC and of standardizing the EBC collection method.

Analysis of Growth Factors and Inflammatory Cytokines in Exhaled Breath Condensate from Asthmatic Children

Background: Vascular endothelial growth factor (VEGF), AA isoform of platelet-derived growth factor (PDGF-AA), and epidermal growth factor (EGF) are involved in the pathogenesis of airway inflammation in asthma. These molecules are closely associated with cytokines such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-4. This study investigates the relation between childhood asthma and levels of these mediators in exhaled breath condensate (EBC). Methods: EBC was collected from asthmatic children and controls using a disposable collection kit, and the concentrations of VEGF, PDGF-AA, EGF, TNF-α and IL-4 in EBC were measured using sandwich enzyme immunoassays. Exhaled nitric oxide concentration was measured by a chemiluminescence analyzer. Results: Thirty-five asthmatic patients aged between 7 and 18 years and 11 controls were recruited. Sixteen patients had intermittent asthma (IA) whereas 19 of them suffered from persistent asthma (PA). A significant correlation was found between IL-4 and TNF-α in EBC (ρ = 0.374, p = 0.010). PDGF-AA levels in EBC were higher in subjects with diminished FEV₁ (p = 0.023) whereas IL-4 concentrations were increased in asthmatics (p = 0.007) as well as subjects with increased plasma total IgE (p = 0.033). Patients with PA receiving high-dose inhaled corticosteroid (ICS) had higher EBC IL-4 concentration than those on low-dose ICS (p = 0.007). Linear regression revealed that PDGF-AA levels in EBC were negatively associated with FEV₁ percentage (β = –0.459, p = 0.006) among the asthmatic patients. Conclusions: IL-4 in EBC is increased in childhood asthma, and growth factors are detectable in a significant proportion of these children. Increased PDGF-AA is found in asthmatics with more severe airflow limitation.

Childhood asthma: Exhaled markers of airway inflammation, asthma control score, and lung function tests

Exhaled markers of airway inflammation become increasingly important in the management of childhood asthma. The aims of the present study are: 1) to compare exhaled markers of inflammation (nitric oxide, carbon monoxide, and acidity of breath condensate) with conventional asthma measures (lung function tests and asthma control score) in childhood asthma; and 2) to investigate the detectability of albumin, CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in the exhaled breath condensate (EBC) of asthmatic children. Thirty-two children with mild to moderate persistent asthma and healthy controls aged 6-12 years were studied. We measured exhaled NO and CO, and subsequently EBC was collected. Inflammatory mediators in EBC were measured using an enzyme-linked immunosorbent assay. Respiratory symptoms and asthma control were assessed using the asthma control questionnaire (ACQ) of Juniper et al. (Eur Respir J 1999;14:902-907). Exhaled NO showed a significant correlation with exhaled CO (r = 0.59, P < 0.05) and FEV1 (r = -0.59, P < 0.05), but not with ACQ score (r = 0.48, P = 0.06). Exhaled CO was correlated with prebronchodilator FEV1 (r = -0.45, P < 0.05), but not with asthma control (r = 0.18, P = 0.35). Acidity of EBC was significantly lower in asthmatic children than in healthy controls (P < 0.05), but did not correlate with any of the conventional asthma measures. We were not able to demonstrate the presence of CRP, IL-6, IL-8, TNF-alpha, sICAM-1, and sTNF-R75 in EBC. Albumin was found in two EBC samples of asthmatic children. We conclude that exhaled NO had a better correlation with lung function parameters and asthma control than exhaled CO and acidity of EBC, in mild to moderate persistent childhood asthma. However, exhaled NO, CO, and deaerated pH of EBC did not differ between asthmatic children and controls, possibly because of a too homogeneous and well-controlled study population. To further evaluate the clinical utility of exhaled markers in monitoring childhood asthma, more studies are required on a wider range of asthma severity, and preferably with repeated measurements of markers and of asthma control.

Exhaled Breath Condensate Detects Markers of Pulmonary Inflammation after Cardiothoracic Surgery

Cardiac surgery using cardiopulmonary by-pass and, to a greater extent, lung resection, causes acute lung injury that is usually subclinical. Analysis of mediators in exhaled breath condensate is a promising means of monitoring inflammation in a variety of airway diseases but the contribution of the airway lining fluid from the lower respiratory tract is uncertain. We compared the analysis of markers of lung injury in exhaled breath condensate and bronchoalveolar lavage in endotracheally intubated patients before and after coronary artery bypass graft surgery with cardiopulmonary bypass and lobectomy. The neutrophil count and leukotriene B4 concentration in bronchoalveolar lavage fluid rose after coronary artery bypass graft surgery (p < 0.05), but there was no significant change in leukotriene B4, hydrogen peroxide, or hydrogen ion concentrations in exhaled breath condensate. By contrast, after lobectomy, the concentration in exhaled breath condensate of leukotriene B4, hydrogen peroxide and hydrogen ions rose significantly (p < 0.05). Exhaled breath condensate is a safe, noninvasive method of sampling the milieu of the distal lung and is sufficiently sensitive to detect markers of inflammation and oxidative stress in patients after lobectomy, but not after the milder insult associated with cardiac surgery.