Use Of Exhaled Breath Condensate Research Articles

Online preconcentration and chiral separation of ofloxacin in exhaled breath condensate by capillary electrophoresis

Breath analysis is an effective method of monitoring systemic or respiratory ailments. A simple chiral capillary electrophoresis method coupled with an online field-amplified sample injection stacking method is presented for ultratrace quantification of the enantiomers of ofloxacin in exhaled breath condensate (EBC). The study is focused on the use of EBC as an easily available biological sample to monitor ofloxacin’s enantiomers levels with good patient compliance. The proposed method was validated in accordance with FDA guidelines over the concentration range of 0.004–1.0 µg mL−1 of racemic ofloxacin. Inter- and intra-day precision and accuracy were within the acceptable limit (below 8.50 %). The method was specific for routine analysis of ofloxacin’s enantiomers. A small volume of EBC samples from seven patients under ofloxacin therapy was analyzed using the proposed method in which the concentrations of “R” and “S” enantiomers were between 0.0026 and 0.056 µg mL−1.

Potential Use of Exhaled Breath Condensate for Diagnosis of SARS-CoV-2 Infections: A Systematic Review and Meta-Analysis.

Background. Reverse-transcriptase polymerase chain reaction (RT-qPCR) assays performed on respiratory samples collected through nasal swabs still represent the gold standard for COVID-19 diagnosis. Alternative methods to this invasive and time-consuming options are still being inquired, including the collection of airways lining fluids through exhaled breath condensate (EBC). Materials and Methods. We performed a systematic review and meta-analysis in order to explore the reliability of EBC as a way to collect respiratory specimens for RT-qPCR for diagnosis of COVID-19. Results. A total of 4 studies (205 specimens), were ultimately collected, with a pooled sensitivity of 69.5% (95%CI 26.8–93.4), and a pooled specificity of 98.3% (95%CI 87.8–99.8), associated with high heterogeneity and scarce diagnostic agreement with the gold standard represented by nasal swabs (Cohen’s kappa = 0.585). Discussion. Even though non-invasive options for diagnosis of COVID-19 are still necessary, EBC-based RT-qPCR showed scarce diagnostic performances, ultimately impairing its implementation in real-world settings. However, as few studies have been carried out to date, and the studies included in the present review are characterized by low numbers and low sample power, further research are requested to fully characterize the actual reliability of EBC-based RT-qPCR in the diagnosis of COVID-19.

Relationship between particle and metal concentrations in subway workers’ personal breath zone (PBZ), exhaled breath condensate (EBC), and urine

BACKGROUND AND AIM: Subway exposure health effects are still unknown. We analyzed particle and metal exposure in the PBZ, EBC and urine of subway workers METHODS: PBZ of nine station agents, locomotive operators and security guards was sampled during 6-h shifts over two weeks. Urine and EBC samples were collected pre- and post-shift. Mass concentrations of PM10, PM2.5 and their metal constituents were determined in PBZ, urine and EBC, along with ultrafine particle (UFP) number in PBZ and EBC. Urine and EBC metal concentrations were standardized by creatinine and EBC volume, respectively, and log-transformed. RESULTS:PBZ PM mass concentrations were above the WHO guideline for indoor air but varied significantly between jobs. Locomotive operators had the highest exposure (189 and 137 μg/m3 for PM10 and PM2.5, respectively), while station agents had the highest UFP exposure (1.97x104 #/cm3). Only Al, Fe and Zn in both PM2.5 and PM10 and Cu and Mn in PM2.5 were above the limit of quantification. By mass fraction, Fe, Cu, Al and Zn were the most abundant. Security guards had the highest Al exposure in both PM2.5 and PM10, while locomotive operators had the highest PM10 Fe exposure. In EBC, the pre/post-shift metal concentrations ordered ZnCuNiBaMn. Security guards had the highest EBC metal concentrations, particularly Zn and Cu. Urinary concentrations ordered SiZnMoTiCuBa≈NiCo. Station agents and locomotive operators had the highest Si and Zn concentrations, respectively. Post-shift EBC Zn and Cu were associated with Zn and Cu concentrations in PM10 and with post-shift urinary Zn and Cu concentrations. Particle number in EBC was significantly correlated with UFP number in PBZ. CONCLUSIONS:This is the first study exploring a triple assessment of particle and metal exposure in a subway. The use of EBC in addition to urine seems more informative for individual airborne exposure biomonitoring in subways. KEYWORDS: particulate matter, ultrafine particles, mass concentration, exposure biomarquer

Use of exhaled breath condensate (EBC) in the diagnosis of SARS-COV-2 (COVID-19)

False negatives from nasopharyngeal swabs (NPS) using reverse transcriptase PCR (RT-PCR) in SARS-CoV-2 are high. Exhaled breath condensate (EBC) contains lower respiratory droplets that may improve detection. We performed EBC...

MicroRNAs in pulmonary sarcoidosis: A systematic review.

Sarcoidosis is a multisystemic granulomatous disorder of unknown etiology. Diagnosis of sarcoidosis is made by correlating clinical and radiological features along with the histopathological demonstration of non-necrotizing granulomas in tissue samples. Diagnosis is often challenging as the clinical profile may mimic other granulomatous disorders, including infections, inflammatory diseases, and lymphoid malignancies. Differentiation from tuberculosis is especially crucial in endemic regions where exclusion of mediastinal tuberculosis is necessary before any immunosuppressant treatment can be initiated for symptomatic sarcoidosis. Identification of biomarkers, which can aid in diagnosis as well as prognosis, can be helpful in clinical decision making. MicroRNAs are small non-coding regulatory RNAs that serve as post-transcriptional regulators of gene expression and have been studied as emerging biomarkers in many other respiratory diseases, including lung cancer, asthma, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. In the context of sarcoidosis, miRNA expression has been studied in the lungs, lymph nodes, bronchoalveolar lavage fluid, and peripheral blood mononuclear cells. A comprehensive search of the PubMed database was performed by two authors independently, and relevant studies were retrieved for review. This systematic review summarizes the current information on miRNAs in sarcoidosis, the biological mechanisms involved in CD4+ T-helper 1 and macrophage polarization, and the use of exhaled breath condensate as an alternative, noninvasive and potential source of miRNAs.

Update on exhaled breath condensate analyses in occupational disease.

The present work represents an update of the review published in this journal by Corradi et al., regarding the use of exhaled breath condensate (EBC) to investigate occupational lung diseases. The relevant literature was searched in the Medline database, assessed through PubMed using key terms such as 'breath AND condensate AND occupational'. Eleven pertinent publications were retrieved between January 2018 and October 2019. One article only was related to occupational allergy, and the conclusion is that EBC hydrogen peroxide is not an useful marker in laboratory animal allergy. The biomarkers of exposure most often assessed with EBC are metals. However, it is controversial whether this approach has any advantage over the conventional environmental monitoring. The biomarkers of effect studied by the majority of investigations were those related to oxidative stress. They appear consistently elevated upon occupational exposures to various agents, including welding fumes, crystalline silica, nanomaterials and chemicals. Although EBC represent a suitable tool to sample airway lining fluid in a noninvasive manner, it remains a niche approach to the investigation of occupational diseases. The confounding influence of EBC dilution should be better addressed in the expression of the results.

A Review of the Usefulness of Non-invasive Exhaled Breath Condensate pH Analysis for Diseases Diagnosis with Elements of Meta-analysis: An Update from 2012

Exhaled breath condensate (EBC) sample analysis is an entirely non-invasive novel sample collection method that is fast, easy to perform, and effort-appeared independent. EBC samples can be very useful in identifying the biomarkers of many diseases. This review provides an updated overview of EBC pH disturbances in different disorders as well as physiological levels among healthy individuals since 2012. Our meta-analysis addresses some of the key questions related to sample processing before pH measurement and discusses various methods of condensate standardization that can be employed prior to conducting a pH assay. Given the recent widespread interest in research into the use of EBC to identify biomarkers, it is necessary to establish a pathway leading from analytical methods for biomarker evaluation using EBC pH to clinical applications of this technology. This review fills a gap in the literature and attempts to connect theory to practical analytical approaches to analyzing EBC samples and making critical treatment-related decisions next to the patient’s bed.

Determining the presence of asthma-related molecules and salivary contamination in exhaled breath condensate

BackgroundResearchers investigating lung diseases, such as asthma, have questioned whether certain compounds previously reported in exhaled breath condensate (EBC) originate from saliva contamination. Moreover, despite its increasing use in ‘omics profiling studies, the constituents of EBC remain largely uncharacterized. The present study aims to define the usefulness of EBC in investigating lung disease by comparing EBC, saliva, and saliva-contaminated EBC using targeted and untargeted mass spectrometry and the potential of metabolite loss from adsorption to EBC sample collection tubes.MethodsLiquid chromatography mass spectrometry (LC-MS) was used to analyze samples from 133 individuals from three different cohorts. Levels of amino acids and eicosanoids, two classes of molecules previously reported in EBC and saliva, were measured using targeted LC-MS. Cohort 1 was used to examine contamination of EBC by saliva. Samples from Cohort 1 consisted of clean EBC, saliva-contaminated EBC, and clean saliva from 13 healthy volunteers; samples were analyzed using untargeted LC-MS. Cohort 2 was used to compare eicosanoid levels from matched EBC and saliva collected from 107 asthmatic subjects. Samples were analyzed using both targeted and untargeted LC-MS. Cohort 3 samples consisted of clean-EBC collected from 13 subjects, including smokers and non-smokers, and were used to independently confirm findings; samples were analyzed using targeted LC-MS, untargeted LC-MS, and proteomics. In addition to human samples, an in-house developed nebulizing system was used to determine the potential for EBC samples to be contaminated by saliva.ResultsOut of the 400 metabolites detected in both EBC and saliva, 77 were specific to EBC; however, EBC samples were concentrated 20-fold to achieve this level of sensitivity. Amino acid concentrations ranged from 196 pg/mL – 4 μg/mL (clean EBC), 1.98 ng/mL – 6 μg/mL (saliva-contaminated EBC), and 13.84 ng/mL – 1256 mg/mL (saliva). Eicosanoid concentration ranges were an order of magnitude lower; 10 pg/mL – 76.5 ng/mL (clean EBC), 10 pg/mL – 898 ng/mL (saliva-contaminated EBC), and 2.54 ng/mL – 272.9 mg/mL (saliva). Although the sample size of the replication cohort (Cohort 3) did not allow for statistical comparisons, two proteins and 19 eicosanoids were detected in smoker vs. non-smoker clean-EBC.ConclusionsWe conclude that metabolites are present and detectable in EBC using LC-MS; however, a large starting volume of sample is required.

Increased inflammatory mediator in exhaled breath condensate from asthmatic children

Purpose: There has recently been increasing interest in the use of exhaled breath condensate (EBC) as a simple noninvasive means for understanding the physiology of asthma. The aim of this study was to evaluate the levels of leukotriene B4 (LTB4) and eosinophil cationic protein (ECP) in the EBC of asthmatic children. Methods: We measured LTB4 and ECP levels in EBC from children aged 6–14 years, including healthy children (n = 25) and asthmatic children (n = 25). We also measured serum LTB4 and serum ECP. Pulmonary function tests and methacholine challenge tests were performed on all subjects. Results: Exhaled LTB4 levels were increased significantly in patients with asthma compared to normal subjects (7.1 ± 3.7 pg/mL vs. 2.2 ± 1.7 pg/mL, P < 0.05). Serum LTB4 levels were not significantly different in patients with asthma compared to normal subjects (674.7 ± 484.1 pg/mL vs. 487.1 ± 272.0 pg/mL, P = 0.156,) and no significant correlations were found between exhaled and serum LTB 4 concentrations in children with asthma (r = 0.052, P = 0.758). Exhaled ECP levels were not significantly different in patients with asthma compared to normal subjects (P = 0.419). Serum ECP levels were significantly increased in patients with asthma compared to normal subjects (44.37 ± 32.14 μg/L vs. 16.40 ± 13.23 μg/L, P = 0.001). Conclusion: We found significantly elevated LTB 4 levels in the EBC of asthmatic children. Our results suggest that EBC may be one of the supportive tools to measure airway inflammation in children with asthma. (Allergy Asthma Respir Dis 2014;2:332-336)

Inflammatory cytokines in exhaled breath condensate in children with inflammatory bowel diseases

Although inflammatory bowel diseases (IBD) affect mainly the gastrointestinal tract, the extra-intestinal manifestations are not uncommon. Different diagnostic methods have been applied to assess pulmonary involvement in patients with IBD, but majority of these methods show significant limitations in children. The aim of our study was to evaluate the usefulness of exhaled breath condensate (EBC) measurements of pro-inflammatory cytokines in children with IBD. Twenty-two children with Crohn's disease (CD) (mean age 13.8 ± 3.3 years), 25 with ulcerative colitis (UC) (mean age 14.1 ± 3.3 years) and 37 healthy volunteers (mean age 13.9 ± 3.6 years) were studied. IBD activity was assessed using appropriate scoring systems. None of the patients had signs or symptoms of pulmonary disease. Exhaled breath condensate was collected and EBC concentration of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin 8 (IL-8) was measured. The concentrations of all the assessed cytokines were significantly higher in the study group as compared to controls. A negative correlation between IL-1β and CD activity index was found. There were no significant relationships between TNF-α, IL-6, or IL-8 level and CD activity index as well as between IL-1β, TNF-α, IL-6, IL-8 and UC activity index. No significant correlation between the concentration of IL-1β, TNF-α, IL-6, IL-8, and IBD duration or treatment duration was found. Elevated concentration of pro-inflammatory cytokines in EBC in children with IBD may suggest the presence of asymptomatic inflammation in the lower airways.

Pulmonary biomarkers in COPD exacerbations: a systematic review

Exacerbations of COPD (ECOPD) represent a major burden for patients and health care systems. Innovative sampling techniques have led to the identification of several pulmonary biomarkers. Although some molecules are promising, their usefulness in clinical practice is not yet established. Medline and Highwire databases were used to identify studies evaluating pulmonary sampled biomarkers in ECOPD. We combined 3 terms for ECOPD, 3 for biomarkers and 6 for the sampling method. Seventy-nine studies were considered eligible for inclusion in the review and were analyzed further. Pulmonary biomarkers sampled with non-invasive, semi-invasive and invasive methods were evaluated for their potential to illustrate the disease’s clinical course, to correlate to clinical variables and to predict clinical outcomes, ECOPD etiology and response to treatment. According to published data several pulmonary biomarkers assessed in ECOPD have the potential to illustrate the natural history of disease through the modification of their levels. Among the clinically relevant molecules, those that have been studied the most and appear to be promising are spontaneous and induced sputum biomarkers for reflecting clinical severity and symptomatic recovery, as well as for directing towards an etiological diagnosis. Current evidence on the clinical usefulness of exhaled breath condensate and bronchoalveolar lavage biomarkers in ECOPD is limited. In conclusion, pulmonary biomarkers have the potential to provide information on the mechanisms underlying ECOPD, and several correlate with clinical variables and outcomes. However, on the basis of published evidence, no single molecule is adequately validated for wide clinical use. Clinical trials that incorporate biomarkers in decisional algorithms are required.

Exhaled breath condensate as a biomonitor for metal exposure: a new analytical challenge

The study of exhaled breath condensate (EBC) obtained by cooling exhaled air under conditions of spontaneous breathing is considered one of the areas with higher interest in respiratory health research. The use of EBC for elemental determination in occupational exposure requires a standard methodological procedure to implement its practice in occupational studies. EBC is an inhomogeneous sample with organic and particulate matter in suspension, which may hamper analytical results reliability. Total reflection X-ray fluorescence and inductive coupled-plasma mass spectrometry (ICP-MS) techniques were chosen as both are multielemental, require small sample volumes and have appropriate detection limits. Estimation of the overall uncertainty in both techniques was carried out using a pool of EBC collected from a group of workers of a lead processing industry to perform precision and trueness studies for K, Mn, Cu, Cd, Sb and Pb. Precision was estimated in terms of repeatability using the native EBC sample pool and trueness in terms of recovery obtained from spiking aliquots of the EBC pool with K, Mn, Cu, Cd, Sb and Pb at different concentrations. Recovery was the most significant contribution to total uncertainty. The overall uncertainties obtained for ICP-MS enabled to discriminate between groups of individuals exposed to different levels of contaminants. Therefore EBC proved to be useful in human biomonitoring.

Exhaled breath 8-isoprostane as a marker of asthma severity.

IntroductionOxidative stress is a non-specific feature of airway inflammation in asthmatics. 8-Isoprostane (8-IP), a prostaglandin-F2α isomer, is a relatively new marker of oxidative stress and may be measured in exhaled breath condensate (EBC) of patients with asthma. This research study aimed to evaluate the usefulness of EBC 8-IP as a marker of severity and control of severe adult asthma.Material and methodsTwenty-seven severe, never-smoking asthmatics were studied. According to positive or negative reversibility testing, this group was subdivided into reversible and irreversible asthma groups. All participants were observed for 8 weeks during which they completed daily diary observations including day and night symptoms, number of awakenings, peak expiratory flow (PEF) variability, daily rescue medication usage and oral steroids consumption. They attended the clinic 3 times and on these occasions spirometry assessments, EBC collection and asthma control tests (ACT) were done. Two control groups were included: 11 healthy never-smokers and 16 newly diagnosed and never-treated, non-smoking mild asthmatics.ResultsThere were no statistically significant differences between severe asthma and healthy control or never-treated asthma groups in concentrations of EBC 8-IP (median and interquartile range: 4.67; 2.50-27.92 vs. 6.93; 2.5-12.98 vs. 3.80; 2.50-10.73, respectively). No correlations were found between EBC 8-IP and asthma control parameters, such as ACT results, night and day symptoms, consumption of rescue medication, percentage of days free of oral steroids, PEF diurnal variation, lung function test results, forced expiratory volume in the 1 s reversibility, and markers of systemic inflammation.ConclusionsOur study results suggest that EBC 8-IP measurements are not useful for asthma monitoring.

Exploring Airway Diseases by NMR-Based Metabonomics: A Review of Application to Exhaled Breath Condensate

There is increasing evidence that biomarkers of exhaled gases or exhaled breath condensate (EBC) may help in detecting abnormalities in respiratory diseases mirroring increased, oxidative stress, airways inflammation and endothelial dysfunction. Beside the traditional techniques to investigate biomarker profiles, “omics” sciences have raised interest in the clinical field as potentially improving disease phenotyping. In particular, metabonomics appears to be an important tool to gain qualitative and quantitative information on low-molecular weight metabolites present in cells, tissues, and fluids. Here, we review the potential use of EBC as a suitable matrix for metabonomic studies using nuclear magnetic resonance (NMR) spectroscopy. By using this approach in airway diseases, it is now possible to separate specific EBC profiles, with implication in disease phenotyping and personalized therapy.

Clinical and Epidemiological Metabonomics

Metabonomics is an omics approach to identify and monitor metabolic characteristics, changes, and phenotypes with respect to various synergetic factors such as environment, life style, diet, and potential pathophysiological processes. Recently, metabonomics has also opened up a possibility for functional genomics in large genome-wide studies. Mass spectrometry (MS) and proton nuclear magnetic resonance (NMR) spectroscopy are the two key experimental technologies in the field. Recent advancements are numerous, and methodologies currently exist that allow for automated high-throughput experimentation in a very cost-effective manner. Technical developments have evoked an increasing number of metabonomics applications in clinical and epidemiological disciplines to understand the complex molecular foundations of various diseases. Techniques with the aim of assessing large numbers of metabolites that are substrates, intermediates, or products in various metabolic pathways are particularly relevant in the risk assessment of metabolic conditions like diabetes and vascular diseases. It has also been envisioned that metabonomics approaches may overtake standard analytical measurements of individual metabolites and eventually lead to holistic multimetabolic risk phenotyping in the early detection of high-risk individuals for various metabolic diseases. Thus, metabonomics offers potential means to move away from single biomarkers and thresholds in clinical medicine. And, furthermore, even though the current medical biomarkers and thresholds are necessary benchmarks for clinical practice, it will be crucial to let the future diagnostics to follow from new science. Good predictions are necessary for effective prevention; an important step towards this is expected to happen when complex traits will not anymore be limited by clinical diagnoses and definitions but will be handled as multivariate continuous dimensions. Consequently, clinical and epidemiological metabonomics is likely to be one of the key new omics areas to assist translational research in the near future. Here, the Journal of Biomedicine and Biotechnology presents this special issue, 2011. Although only representing a small fraction of the contribution of metabonomics to various biomedical disciplines, the papers presented here show the increasing potential of metabonomics approaches to complement clinical and epidemiological research. To start the special issue, we have five contributions that review several aspects of metabonomics research. M. G. Barderas et al. discuss the concepts of metabolic profiling, fingerprinting, and footprinting focusing on the area of cardiovascular diseases. E. Silvestri and coworkers discuss the timely and relevant issue of integrative analyses of related omics data sets in order to furnish new insights not accessible through one-dimensional data. Further, I. Kouskoumvekaki and G. Panagiotou give an extensive up-to-date overview on the database resources on metabolic pathways and metabolomes and also summarize the statistical tools often used for the analysis of metabonomics data. Y. Kim and S. Milner deal with the challenges related to bioactive food components in cancer research and prevention. Moreover, M. Sofia and coauthors review the potential use of exhaled breath condensate as a suitable matrix for NMR-based metabonomics of airway diseases. This special issue contains two methodology reports. G. Kastenmuller and coworkers have developed a freely accessible methodology to facilitate automated and standardized analysis for quantitative metabolic data, covering the steps from data acquisition to biological interpretation. M. C. Martinez-Bisbal and colleagues, using magnetic resonance microscopy, present a critical and valuable interpretation on the high-resolution magic angle spinning data of human tumor tissues. The six original research papers in this special issue start with the paper by J. Willmann et al. who demonstrate the advantage of combining high-pressure liquid chromatography, MS, and NMR spectroscopy in analyzing three different types of extracts of a common membrane component phosphatidylcholine. Then, D. F. Brougham et al. focus on the use of artificial neural networks in classifying proton NMR spectroscopic data recorded on whole-cell culture samples of four different lung carcinoma cell lines, displaying different drug-resistance patterns. In a mouse study, D. Otter et al. apply MS-based nontargeted urinary metabolite profiling to identify biomarkers of colon inflammation. In another mouse study, J. Zhou et al. provide evidence that NMR metabonomics may be sensitive enough to detect small differences in the composition of maternal plasma and thus be helpful for identifying biomarkers of birth defects. Additionally, in low-birth weight and high-birth weight piglets P. M. Nissen and coworkers combine NMR and MS to reveal a relationship between birth weight and plasma inositols, suggesting their potential role in fetal programming of type 2 diabetes. L. Guo et al. end this special issue in providing the latest epidemiologic information on the etiology distribution of neurodevelopmental disabilities in Chinese, and by demonstrating, on the basis of 8-year clinical experience, that MS-based pediatric metabonomics is clinically helpful. Overall, we hope that this special issue hints at the rising potential of metabonomics approaches in clinical and epidemiological research and translational medicine. Mika Ala-Korpela Veikko Salomaa Olav M. Kvalheim

Use of exhaled breath condensate to investigate occupational lung diseases

The present study reviews recent data concerning the assessment of exhaled breath condensate (EBC) pulmonary biomarkers in the field of occupational medicine. EBC is a suitable matrix to assess respiratory health status in workers exposed to pneumotoxic substances, due to its ability to quantify lung tissue dose and consequent pulmonary effects. Published data show that toxic metals and trace elements are detectable in EBC, raising the possibility of using this medium to quantify the lung tissue dose of metals occurring in occupational settings. EBC analysis of biomarkers of exposure highlighted the potential use of EBC as completion of the biological monitoring of pneumotoxic compounds. Different biomarkers of effect, such as oxidative stress and inflammatory-derived biomarkers have been applied in the investigation of occupational asthma and pneumoconiosis, suggesting that the collection of EBC may contribute to studying the pathological state of the airways of workers with acute and chronic exposure to pollutants. EBC measurements also seem to be reliable to detect the presence of carcinogenic processes in the respiratory system, by the analysis of various markers of oxidative stress, angiogenesis and DNA alterations related to lung cancer. This approach may open new frontiers in the study of workers currently or previously exposed to pulmonary carcinogenic agents. The analysis of EBC is one of the most promising methods currently available for the study of pulmonary biomarkers of exposure, effect and susceptibility in occupational settings; being collected in a totally noninvasive way, it is particularly suitable to be applied in field studies and for longitudinal assessments of pulmonary biology.

A utilização do condensado do exalado pulmonar poderá ser incorporada à rotina de unidades de tratamento intensivo?

Endogenous production of nitric oxide can be detected and monitored in exhaled air of men and animals. The main objective of this review was to discuss if nitric oxide in exhaled breath condensate is a useful tool when investigating respiratory dysfunctions in intensive care units. Specialized literature reveals an increasing interest in the use of exhaled breath condensate as a non-invasive method to investigate pulmonary disease. However, a standardized method for its collection is lacking, and use of different methods of respiratory support complicates comparison among different studies. In addition, the same specialized literature review emphasized possible difficulties for routine use of the exhaled breath condensate in intensive care patients, mainly under mechanical ventilation. Until exhaled breath condensate becomes a routine tool of research and monitoring of intensive care patients, more specific studies and technologies are still necessary. Its importance has been related to physiological control of the pulmonary function and to physiopathology of pulmonary disease involving chronic inflammation and oxidative stress.

Exhaled breath condensate and airway inflammation

The collection of exhaled breath condensate (EBC) is a noninvasive method for evaluation of airway inflammation. This article reviews recent data concerning the ability of EBC markers to reflect alterations in asthma and chronic obstructive pulmonary disease or environment and occupation-induced changes. The recovery of biomarkers in EBC is affected by physical characteristics of the condensing device and collecting circumstances as well as environmental conditions or exercise. The complexities of nitrogen oxide chemistry make assessment of nitric oxide metabolites in EBC and exhaled nitric oxide complementary. Analysing of EBC markers is valuable in asthma, as changes were reported irrespective of current anti-inflammatory treatment or atopic status as well as in monitoring cigarette smoking-related airway inflammation in chronic obstructive pulmonary disease patients. Hyperinflation in chronic obstructive pulmonary disease might be a potential confounder for the level of inflammation markers in EBC. In general, patterns of markers are likely to more accurately reflect the complex pathophysiological processes and therefore should be evaluated rather than a single marker. EBC might be of particular interest in preventive medicine as inflammatory processes triggered may precede changes in lung function. Robust and easy-to-handle condensing devices and analytical methods are warranted to spread the use of EBC.

Exhaled breath malondialdehyde as a marker of effect of exposure to air pollution in children with asthma

Assessment of the adverse effects of oxidative stress related to air pollution is limited by the lack of biological markers of dose to the lungs. We evaluated the use of exhaled breath condensate (EBC) malondialdehyde as a biomarker of exposure to traffic-related pollution in children with asthma as part of a panel study in Mexico City. Standard spirometry and collection of EBC and nasal lavage were performed. Environmental monitoring sites were located within 5 km of the children's homes and schools. Data were analyzed by using generalized estimating equations. A total of 480 samples of malondialdehyde were obtained from 107 patients with asthma, with a median level of 18.7 (interquartile range [IQR], 12.4-28.7) nmol. Ambient particulates less than 2.5 microg/m(3) and ozone levels on the day of sampling were significantly associated with higher malondialdehyde levels. A 14.2-microg/m(3) (IQR) increase in 8-hour moving average particulates less than 2.5 microg/m(3) in size was associated with a 1.12-nmol increase in malondialdehyde and a 15.9-ppb (IQR) increase in 8-hour moving average ozone with a 1.16-nmol increase in malondialdehyde. Malondialdehyde levels were inversely associated with forced vital capacity and FEV(1) and positively associated with IL-8 levels in nasal lavage. Exhaled breath condensate malondialdehyde was related to both air pollution exposure and changes in lung function and inflammatory markers.

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.