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

Exhaled Breath Condensate: An Update

Exhaled breath condensate (EBC) is a promising source of biomarkers of lung disease. EBC research and utility has increased substantially over the past 2 decades. This review summarizes many of the factors regarding the composition of EBC, its collection, and analysis for the utility of both clinicians and researchers.

Non-volatile compounds in exhaled breath condensate: review of methodological aspects

In contrast to bronchial and nasal lavages, the analysis of exhaled breath condensate (EBC) is a promising, simple, non-invasive, repeatable, and diagnostic method for studying the composition of airway lining fluid with the potential to assess lung inflammation, exacerbations, and disease severity, and to monitor the effectiveness of treatment regimens. Recent investigations have revealed the potential applications of EBC analysis in systemic diseases. In this review, we highlight the analytical studies conducted on non-volatile compounds/biomarkers in EBC. In contrast to other related articles, this review is classified on the basis of analytical techniques and includes almost all the applied methods and their methodological limitations for quantification of non-volatile compounds in EBC samples, providing a guideline for further researches. The studies were identified by searching the SCOPUS database with the keywords "biomarkers," "non-volatile compounds," "determination method," and "EBC."

Evaluating Cytokines in Immunotoxicity Testing

One of the most powerful tools in immunotoxicology is the assessment of cytokines, the proteins/peptides responsible for regulating a variety of processes including immunity, inflammation, apoptosis, and hematopoiesis. Cytokine production measurements offer outstanding information and may eventually substitute for other more laborious procedures in the assessment of immunotoxicity. The particular profile of cytokine production provides indeed important information regarding the nature of many immunotoxic responses.Recent expansion in the knowledge of cytokine biology and the realization that cytokines play a role in human diseases have created a need for the precise assessment and accurate interpretation of their presence and activity in body fluids, tissues, and cells. Proper evaluation of cytokines requires attention to several technical details. Multi-cytokine analysis still needs to be standardized in terms of optimum source for analysis, protocols, and quality control issues, such as the use of reference standards and the expression of results.Important practical details and considerations will be discussed in this chapter, including the source of the sample to be tested (circulating fluids or ex vivo/in vitro isolated cells); the potential effects of collection, processing, and storage of the results of the assays, as well as potential variables associated with the source material (matrix effects, relevance, inhibitory substances); and factors influencing the choice of assay used (bioassay, immunoassay, molecular biology technique, flow cytometry).

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

IL-8 and pH Values in Exhaled Condensate after Antibiotics in Cystic Fibrosis Children

Interleukin (IL)-8 is a major factor in inflammatory response and the IL-8 levels in exhaled breath condensate (EBC) may be used as a marker of airway inflammation. Airway acidification is implicated in the pathophysiology of obstructive airway diseases and pH EBC values have been used as a marker of airway acidification. The aim of our study is to investigate whether IL-8 and pH levels in EBC of cystic fibrosis (CF) children with respiratory exacerbations change after antibiotic treatment. Lung function, IL-8 and pH EBC values were measured in fifteen CF children (mean age 11 years) with acute exacerbation before (T0) and after two weeks (T1) of antibiotic treatment. IL-8 and pH values were compared by paired t-test. A p<0.05 was considered significant. IL-8 EBC levels decreased after antibiotic treatment (TO 0.36±0.03pg/ml vs T1 0.28±0.03pg/ml; p=0.03) and pH values increased (TO 7.3610.09 vs T1 7.61±0.08; p=0.04). Results suggest possible application of EBC as a non-invasive tool to monitor efficacy of antibiotic treatment in CF patients.

The analysis of volatile organic compounds in exhaled breath and biomarkers in exhaled breath condensate in children - clinical tools or scientific toys?

Current monitoring strategies for respiratory diseases are mainly based on clinical features, lung function and imaging. As airway inflammation is the hallmark of many respiratory diseases in childhood, noninvasive methods to assess the presence and severity of airway inflammation might be helpful in both diagnosing and monitoring paediatric respiratory diseases. At present, the measurement of fractional exhaled nitric oxide is the only noninvasive method available to assess eosinophilic airway inflammation in clinical practice. We aimed to evaluate whether the analysis of volatile organic compounds (VOCs) in exhaled breath (EB) and biomarkers in exhaled breath condensate (EBC) is helpful in diagnosing and monitoring respiratory diseases in children. An extensive literature search was conducted in Medline, Embase and PubMed on the analysis and applications of VOCs in EB and EBC in children. We retrieved 1165 papers, of which nine contained original data on VOCs in EB and 84 on biomarkers in EBC. These were included in this review. We give an overview of the clinical applications in childhood and summarize the methodological issues. Several VOCs in EB and biomarkers in EBC have the potential to distinguish patients from healthy controls and to monitor treatment responses. Lack of standardization of collection methods and analysis techniques hampers the introduction in clinical practice. The measurement of metabolomic profiles may have important advantages over detecting single markers. There is a lack of longitudinal studies and external validation to reveal whether EB and EBC analysis have added value in the diagnostic process and follow-up of children with respiratory diseases. In conclusion, the use of VOCs in EB and biomarkers in EBC as markers of inflammatory airway diseases in children is still a research tool and not validated for clinical use.

Exhaled Breath Condensate: Technical and Diagnostic Aspects

Purpose. The aim of this study was to evaluate the 30-year progress of research on exhaled breath condensate in a disease-based approach. Methods. We searched PubMed/Medline, ScienceDirect, and Google Scholar using the following keywords: exhaled breath condensate (EBC), biomarkers, pH, asthma, gastroesophageal reflux (GERD), smoking, COPD, lung cancer, NSCLC, mechanical ventilation, cystic fibrosis, pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis, interstitial lung diseases, obstructive sleep apnea (OSA), and drugs. Results. We found 12600 related articles in total in Google Scholar, 1807 in ScienceDirect, and 1081 in PubMed/Medline, published from 1980 to October 2014. 228 original investigation and review articles were eligible. Conclusions. There is rapidly increasing number of innovative articles, covering all the areas of modern respiratory medicine and expanding EBC potential clinical applications to other fields of internal medicine. However, the majority of published papers represent the results of small-scale studies and thus current knowledge must be further evaluated in large cohorts. In regard to the potential clinical use of EBC-analysis, several limitations must be pointed out, including poor reproducibility of biomarkers and absence of large surveys towards determination of reference-normal values. In conclusion, contemporary EBC-analysis is an intriguing achievement, but still in early stage when it comes to its application in clinical practice.

Analysis of inflammatory cytokines in human blood, breath condensate, and urine using a multiplex immunoassay platform

A change in the expression of cytokines in human biological media indicates an inflammatory response to external stressors and reflects an early step along the adverse outcome pathway (AOP) for various health endpoints. To characterize and interpret this inflammatory response, methodology was developed for measuring a suite of 10 different cytokines in human blood, exhaled breath condensate (EBC), and urine using an electrochemiluminescent multiplex Th1/Th2 cytokine immunoassay platform. Measurement distributions and correlations for eight interleukins (IL) (1β, 2, 4, 5, 8, 10, 12p70 and 13), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) were evaluated using 90 blood plasma, 77 EBC, and 400 urine samples collected from nominally healthy adults subjects in North Carolina in 2008-2012. The in vivo results show that there is sufficient sensitivity for characterizing all 10 cytokines at levels of 0.05-0.10 ρg/ml with a dynamic range up to 100 ng/ml across all three of these biological media. The measured in vivo results also show that the duplicate analysis of blood, EBC and urine samples have average estimated fold ranges of 2.21, 3.49, and 2.50, respectively, which are similar to the mean estimated fold range (2.88) for the lowest concentration (0.610 ρg/ml) from a series of spiked control samples; the cytokine method can be used for all three biological media. Nine out of the 10 cytokines measured in EBC were highly correlated within one another with Spearman ρ coefficients ranging from 0.679 to 0.852, while the cytokines measured in blood had a mix of negative and positive correlations, ranging from -0.620 to 0.836. Almost all correlations between EBC and blood were positive. This work also represents the first successful within- and between-person evaluation of ultra trace-level inflammatory markers in blood, EBC, and urine.

PROTEINS, PEPTIDES AND AMINO ACIDS AS MARKERS OF BRONCHOPULMONARY DISEASES

The article is a review of current literature on a content of proteins, peptides and amino acids in human exhaled breath. The results of proteomics and metabolomics applying for selective detection of individual proteins, peptides and amino acids are described. The study of exhaled breath condensate and exhaled endogenous particles contained lung proteins are considered. The peculiarities of protein, peptide and amino acid content in exhaled breath at various respiratory diseases are described. It is shown that the detectable substances may be specific markers of individual diseases.

Breath tests in respiratory and critical care medicine: from research to practice in current perspectives

Today, exhaled nitric oxide has been studied the most, and most researches have now focused on asthma. More than a thousand different volatile organic compounds have been observed in low concentrations in normal human breath. Alkanes and methylalkanes, the majority of breath volatile organic compounds, have been increasingly used by physicians as a novel method to diagnose many diseases without discomforts of invasive procedures. None of the individual exhaled volatile organic compound alone is specific for disease. Exhaled breath analysis techniques may be available to diagnose and monitor the diseases in home setting when their sensitivity and specificity are improved in the future.

Novel end points for clinical trials in young children with cystic fibrosis

Cystic fibrosis (CF) lung disease commences early in the disease progression and is the most common cause of mortality. While new CF disease-modifying agents are currently undergoing clinical trial evaluation, the implementation of such trials in young children is limited by the lack of age-appropriate clinical trial end points. Advances in infant and preschool lung function testing, imaging of the chest and the development of biochemical biomarkers have led to increased possibility of quantifying mild lung disease in young children with CF and objectively monitoring disease progression over the course of an intervention. Despite this, further standardization and development of these techniques is required to provide robust objective measures for clinical trials in this age group.

The role of exhaled nitric oxide and exhaled breath condensates in evaluating airway inflammation in asthma

BACKGROUND

Airway inflammation is central to the development and progression of asthma. Monitoring airway inflammation can be invasive and technically difficult, making its use limited in clinical practice. Several advances have been made in non-invasive techniques to monitor and measure inflammation from the airways.

OBJECTIVE

To examine the suitability of exhaled nitric oxide and exhaled breath condensates as diagnostic tools in asthma.

METHOD

The current literature regarding the use of exhaled nitric oxide and exhaled breath condensate to assess and manage asthma was reviewed.

CONCLUSION

Exhaled nitric oxide is a clinically useful marker of eosinophilic airway inflammation in asthma. Although showing promise, significant validation and investigation are required before exhaled breath condensate could be utilized in clinical practice.

Exhaled breath condensate: a promising source for biomarkers of lung disease

Exhaled breath condensate (EBC) has been increasingly studied as a noninvasive research method for sampling the alveolar and airway space and is recognized as a promising source of biomarkers of lung diseases. Substances measured in EBC include oxidative stress and inflammatory mediators, such as arachidonic acid derivatives, reactive oxygen/nitrogen species, reduced and oxidized glutathione, and inflammatory cytokines. Although EBC has great potential as a source of biomarkers in many lung diseases, the low concentrations of compounds within the EBC present challenges in sample collection and analysis. Although EBC is viewed as a noninvasive method for sampling airway lining fluid (ALF), validation is necessary to confirm that EBC truly represents the ALF. Likewise, a dilution factor for the EBC is needed in order to compare across subjects and determine changes in the ALF. The aims of this paper are to address the characteristics of EBC; strategies to standardize EBC sample collection and review available analytical techniques for EBC analysis.

The effect of academic exam stress on mucosal and cellular airway immune markers among healthy and allergic individuals

Research suggests that psychological stress can exacerbate allergies, but relatively little is known about the effect of stress on mucosal immune processes central to allergic pathophysiology. In this study, we quantified vascular endothelial growth factor (VEGF), interferon gamma (IFN-γ), and interleukin-4 concentrations in saliva (S) and exhaled breath condensate (EBC) during final exams and at midsemester among 23 healthy and 21 allergic rhinitis individuals. IFN-γs decreased during exams for both groups while VEGF(EBC) increased (and increases in VEGFs were a trend). Elevated negative affect ratings predicted higher VEGF(EBC) in allergic individuals. IFN-γ(EBC) increased in healthy individuals early during exams and then decreased, while allergic individuals showed a decrease in IFN-γ(EBC) throughout final exams. These findings suggest that psychological stress can suppress cellular immune function among allergic individuals while increasing VEGF.

Exhaled breath condensate: an overview

Exhaled breath condensate (EBC) is a promising source of biomarkers of lung disease. EBC may be thought of either as a body fluid or as a condensate of exhaled gas. There are 3 principal contributors to EBC: variable-sized particles or droplets that are aerosolized from the airway lining fluid, distilled water that condenses from gas phase out of the nearly water-saturated exhalate, and water-soluble volatiles that are exhaled and absorbed into the condensing breath. The nonvolatile constituents and the water-soluble volatile constituents are of particular interest. Several key issues are discussed in this article.

Methodological aspects of exhaled breath condensate collection and analysis

The collection and analysis of exhaled breath condensate (EBC) may be useful for the management of patients with chronic respiratory disease at all ages. It is a promising technique due to its apparent simplicity and non-invasiveness. EBC does not disturb an ongoing respiratory inflammation. However, the methodology remains controversial, as it is not yet standardized. The current diversity of the methods used to collect and preserve EBC, the analytical pitfalls and the high degree of within-subject variability are the main issues that hamper further development into a clinical useful technique. In order to facilitate the process of standardization, a simplified schematic approach is proposed. An update of available data identified open issues on EBC methodology. These issues were then classified into three separate conditions related to their influence before, during or after the condensation process: (1) pre-condenser conditions related to subject and/or environment; (2) condenser conditions related to condenser equipment; and (3) post-condenser conditions related to preservation and/or analysis. This simplified methodological approach highlights the potential influence of the many techniques used before, during and after condensation of exhaled breath. It may also serve as a methodological checklist for a more systematical approach of EBC research and development.

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.

Biomarkers of immunotoxicity for environmental and public health research

The immune response plays an important role in the pathophysiology of numerous diseases including asthma, autoimmunity and cancer. Application of biomarkers of immunotoxicity in epidemiology studies and human clinical trials can improve our understanding of the mechanisms that underlie the associations between environmental exposures and development of these immune-mediated diseases. Immunological biomarkers currently used in environmental health studies include detection of key components of innate and adaptive immunity (e.g., complement, immunoglobulin and cell subsets) as well as functional responses and activation of key immune cells. The use of high-throughput assays, including flow cytometry, Luminex, and Multi-spot cytokine detection methods can further provide quantitative analysis of immune effects. Due to the complexity and redundancy of the immune response, an integrated assessment of several components of the immune responses is needed. The rapidly expanding field of immunoinformatics will also aid in the synthesis of the vast amount of data being generated. This review discusses and provides examples of how the identification and development of immunological biomarkers for use in studies of environmental exposures and immune-mediated disorders can be achieved.

Increased cytokines, chemokines and soluble adhesion molecules in exhaled breath condensate of asthmatic children

BACKGROUND

Airway inflammation in asthma is characterized by the production of cytokines, chemokines and soluble adhesion molecules. The assessment of these inflammatory biomarkers in exhaled breath condensate (EBC) is hampered by low detection rates. However, the use of a glass condenser system combined with a sensitive analytical technique may increase the possibility to assess these biomarkers in EBC in a reliable way.

OBJECTIVE

(1) To assess the detection rates of cytokines (IL-1alpha, -1beta, -2, -4, -5, -6, -10, -12p70, -13, -18, IFN-gamma, TNF-alpha), chemokines [MIP1alpha (CCL3), MIF, eotaxin (CCL11), RANTES (CCL5), IP10 (CXCL10), IL8 (CXCL8), MCP1] and soluble adhesion molecules [soluble intercellular adhesion molecule (sICAM), soluble vascular adhesion molecule (sVCAM)] in EBC of children with asthma and healthy control children; (2) To study the differences in the biomarker concentration between children with asthma and controls.

METHODS

Sixty children were included: 31 asthmatics (71% atopic) and 29 controls. Exhaled breath condensate was collected using a glass condenser system. The inflammatory markers (IM) were analysed using multiplex immunoassay technology.

RESULTS

Detection percentages of cytokines, chemokines and adhesion molecules ranged from 94% to 100%, except for eotaxin (CCL11) and RANTES (CCL5) (detection rates of 10% and 45% in healthy controls, respectively). The intra-subject variability of biomarkers in EBC in the group as a whole ranged from 5.2% to 35.0%. In asthmatics, the levels of cytokines (IL-2, -4, -5, -6, -13, IFN-gamma), chemokines (MIP1alpha [CCL3], MIF, RANTES [CCL5], IP10 [CXCL10], IL8 [CXCL8], MCP1) and adhesion molecules (sICAM, sVCAM) were significantly increased in comparison with controls (P<0.05).

CONCLUSION

If collected with a glass condenser and analysed by multiplex immunoassay technology, cytokines, chemokines and soluble adhesion molecules can be reliably demonstrated in EBC of children. Most of these IM were elevated in EBC of asthmatics compared with controls.

Effects of a short-term rehabilitation program on airway inflammation in children with cystic fibrosis

BACKGROUND

Respiratory therapy in cystic fibrosis (CF) consists of airway clearance, infection control, and reduction of airway inflammation. It is well recognized that physical activity as well as daily chest physiotherapy, enhance airway clearance. We investigated the effects of pulmonary rehabilitation, including physical activity and chest physiotherapy, on airway inflammation in children with CF.

METHODS

Eighteen children with stable CF (six females), aged 8.2-16.2 years, participating in a 3-week multidisciplinary inpatient rehabilitation program were recruited. Assessment at the beginning and the end of the program included clinical score, pulmonary function test, exhaled breath condensate (EBC) and sputum analysis. Sputum supernatant and EBC were analyzed for interleukin (IL)-1b, 6, 8, 10, 12, tumor necrosis factor-alpha (TNF-alpha) and LTB4.

RESULTS

Median (IQR) symptom scores decreased from 19 [23] to 16 [21], P = 0.005. Vital capacity and FVC increased significantly (P < 0.05). However no difference was found for the total sputum cells and sputum as well as EBC cytokines between the two visits. Significant correlations were found for sputum IL-1 (+), IL-6 (-), and IL-8 (+) to total sputum cell count and neutrophils and for IL-8 to TNF-alpha.

CONCLUSIONS

We have shown that a short-term inpatient rehabilitation for children with stable CF with intensive physical activity mainly improve subjective clinical symptoms and measures of lung function such as VC and FVC but does not influence airflow obstruction and airway inflammation as assessed by sputum and EBC analysis.

Structural lung changes, lung function, and non-invasive inflammatory markers in cystic fibrosis

Cystic fibrosis (CF) lung disease is characterized by chronic airway inflammation and recurrent infections, resulting in (ir)reversible structural lung changes and a progressive decline in lung function. The objective of this study was to investigate the relationship between non-invasive inflammatory markers (IM) in exhaled breath condensate (EBC), lung function indices and structural lung changes, visualized by high resolution computed tomography (HRCT) scans in CF. In 34 CF patients, lung function indices (forced expiratory volume in 1 s, forced vital capacity [FVC], residual volume, and total lung capacity [TLC]) and non-invasive IM (exhaled nitric oxide, and condensate acidity, nitrate, nitrite, 8-isoprostane, hydrogen peroxide, interferon-gamma) were assessed. HRCT scans were scored in a standardized and validated way, a composite score and component scores were calculated. In general, the correlations between non-invasive IM and structural lung changes, and between IM and lung function were low (correlation coefficients <0.40). Patients with positive sputum Pseudomonas cultures had higher EBC nitrite levels and higher parenchymal HRCT subscores than patients with Pseudomonas-negative cultures (p < 0.05). Multiple linear regression models demonstrated that FVC was significantly predicted by hydrogen peroxide in EBC, and the scores of bronchiectasis and mosaic perfusion (Pearson correlation coefficient R = 0.78, p < 0.001). TLC was significantly predicted by 8-isoprostane, nitrate, hydrogen peroxide in EBC, and the mucous plugging subscore (R = 0.92, p < 0.01). Static and dynamic lung function indices in this CF group were predicted by the combination of non-invasive IM in EBC and structural lung changes on HRCT imaging. Future longitudinal studies should reveal whether non-invasive monitoring of airway inflammation in CF adds to better follow-up of patients.

Feasibility of a new method to collect exhaled breath condensate in pre-school children

Exhaled breath condensate (EBC) is a promising non-invasive method to assess respiratory inflammation in adults and children with lung disease. Especially in pre-school children, condensate collection is hampered by long sampling times because of open-ended collection systems. We aimed to assess the feasibility of condensate collection in pre-school children using a closed glass condenser with breath recirculation system, which also collects the residual non-condensed exhaled breath, and subsequently recirculates it back into the condenser. Condensate was collected before and after breath recirculation in 70 non-sedated pre-school children with and without recurrent wheeze. Cytokines (IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α) were measured in 50 μl samples using ultrasensitive multiplexed liquid bead array. The success rate of condensate collection increased from 64% (without recirculation) to 83% (after breath recirculation), and mean condensate volume from 214 to 465 μl respectively. Detection of cytokines was successful in 95-100% of samples. Cytokine concentrations before and after breath recirculation were not different (p > 0.232). In asthmatic children, only TNF-α concentrations were significantly decreased, compared to non-asthmatics. In pre-school children, the collection of EBC is feasible using a new closed glass condenser with breath recirculation system. This new method may help to assess - non-invasively - cytokine profiles in asthmatic and non-asthmatic pre-school children.

Evaluating cytokines in immunotoxicity testing

One of the most potentially useful tools in immunotoxicology is the assessment of cytokines, the proteins/peptides that are responsible for regulating a variety of processes including immunity, inflammation, apoptosis, and hematopoiesis. Cytokine production measurements offer an outstanding promise and may eventually substitute for other more laborious procedures. The particular profile of cytokine production may provide an important information regarding the nature of many immunotoxic responses.Recent expansion in the knowledge of cytokine biology and the realization that cytokines play a role in human diseases have created a need for the precise assessment and accurate interpretation of their presence and activity in the body fluids, tissues and cells. Proper evaluation of cytokines requires attention to several technical details. Multi-cytokine analysis still needs to be standardized in terms of optimum source for analysis, protocols and quality control issues, such as the use of reference standards and the expression of results.Important practical details and considerations will be discussed in this chapter, including the source of the sample to be tested (circulating fluids, or ex vivo/in vitro isolated cells), the potential effects of collection, processing, and storage of the results of the assays, as well as potential variables associated with the source material (matrix effects, relevance, inhibitory substances), and factors influencing the choice of assay used (bioassay, immunoassay, molecular biology technique, flow cytometry).

Differentiation of gram-negative bacterial aerosol exposure using detected markers in bronchial-alveolar lavage fluid

The identification of biosignatures of aerosol exposure to pathogens has the potential to provide useful diagnostic information. In particular, markers of exposure to different types of respiratory pathogens may yield diverse sets of markers that can be used to differentiate exposure. We examine a mouse model of aerosol exposure to known Gram negative bacterial pathogens, Francisella tularensis novicida and Pseudomonas aeruginosa. Mice were subjected to either a pathogen or control exposure and bronchial alveolar lavage fluid (BALF) was collected at four and twenty four hours post exposure. Small protein and peptide markers within the BALF were detected by matrix assisted laser desorption/ionization (MALDI) mass spectrometry (MS) and analyzed using both exploratory and predictive data analysis methods; principle component analysis and degree of association. The markers detected were successfully used to accurately identify the four hour exposed samples from the control samples. This report demonstrates the potential for small protein and peptide marker profiles to identify aerosol exposure in a short post-exposure time frame.

Exhaled leukotrienes and bronchial responsiveness to methacholine in patients with seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis and bronchial asthma can coexist and affect each other.

OBJECTIVE

To investigate the relationship between the postseasonal increase in the concentration of leukotriene (LT) B4 and LTE4 in exhaled breath condensate (EBC) and bronchial responsiveness to methacholine (BRM) in patients with seasonal allergic rhinitis (SAR).

METHODS

In 28 patients with SAR and 50 healthy study patients, the leukotrienes were measured in EBC during and after the pollen season by gas chromatography/mass spectrometry. The BRM was determined after the pollen season.

RESULTS

In 7 patients with SAR, significantly increased concentrations of both the leukotrienes were found in EBC during and 5 months after the pollen season. The following seasonal and postseasonal median values were measured in patients with SAR in comparison with control patients: LTB4: 131 and 90 pg/mL vs 80 and 79 pg/mL, P < .001 and P = .03, respectively; LTE4: 122 and 86 pg/mL vs 76 and 74 pg/mL, P < .001 and P = .02, respectively. Five months after the pollen season, the concentrations of LTB4 and LTE4 decreased with respect to their seasonal values (90 and 86 pg/mL, respectively, P < .001, for both leukotrienes). In 7 patients with SAR and leukotriene levels exceeding the reference limits, significantly increased BRM was also found (LTB4: P = .02; LTE4: P = .002).

CONCLUSIONS

The seasonal and postseasonal increases in LTB4 and LTE4 concentrations in EBC of the patients with SAR correlated significantly with the later increase in BMR. This relationship could provide a useful predictive parameter for early inflammatory processes in the lower airways of patients with allergic rhinitis.

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.

Biomarkers in exhaled breath condensate indicate presence and severity of cystic fibrosis in children

Chronic airway inflammation is present in cystic fibrosis (CF). Non-invasive inflammometry may be useful in disease management. The aim of the present cross-sectional study was to investigate: (i) the ability of fractional exhaled nitric oxide and inflammatory markers (IM) [exhaled breath condensate (EBC) acidity, nitrite, nitrate, hydrogen peroxide (H(2)O(2)), 8-isoprostane, Th1/Th2 cytokines] to indicate (exacerbations of) CF; and (ii) the ability of these non-invasive IM to indicate CF disease severity. In 98 children (48 CF/50 controls), exhaled nitric oxide was measured using the NIOX, and condensate was collected using a glass condenser. In CF interferon (IFN-gamma) and nitrite concentrations were significantly higher, whereas exhaled nitric oxide levels were significantly lower compared with controls (3.3 +/- 0.3 pg/ml, 2.2 +/- 0.2 microM, 10.0 +/- 1.2 p.p.b. vs. 2.6 +/- 0.2 pg/ml, 1.4 +/- 0.1 microM, 15.4 +/- 1.4 p.p.b. respectively). Using multivariate logistic regression models, the presence of CF was best indicated by 8-isoprostane, nitrite and IFN-gamma [sensitivity 78%, specificity 83%; area under receiver operating characteristic curve (AUC) 0.906, p < 0.001]. An exacerbation of CF was best indicated by 8-isoprostane and nitrite (sensitivity 40%, specificity 97%, AUC curve 0.838, p = 0.009). Most indicative biomarkers of CF severity were exhaled nitric oxide, and condensate acidity (sensitivity 96%, specificity 67%; AUC curve 0.751, p = 0.008). In this cross-sectional study, the combination of different exhaled IM could indicate (exacerbations of) CF, and severity of the disease in children. Longitudinal data are necessary to further confirm the role of these markers for the management of CF in children.

Exhaled breath condensate in patients with asthma: implications for application in clinical practice

Exhaled breath condensate (EBC) analysis, a rather appealing and promising method, can be used to evaluate conveniently and non-invasively a wide range of molecules from the respiratory tract, and to understand better the pathways propagating airway inflammation. A large number of mediators of inflammation, including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, prostanoids, nitrogen oxides, peptides and cytokines, have been studied in EBC. Concentrations of such mediators have been shown to be related to the underlying asthma and its severity and to be modulated by therapeutic interventions. Despite the encouraging positive results to date, the introduction of EBC in everyday clinical practice requires the resolution of some methodological pitfalls, the standardization of EBC collection and finally the identification of a reliable biomarker that is reproducible has normal values and provides information regarding the underlying inflammatory process and the response to treatment. So far, none of the parameters studied in EBC fulfils the aforementioned requirements with one possible exception: pH. EBC pH is reproducible, has normal values, reflects a significant part of asthma pathophysiology and is measurable on-site with standardized methodology although some methodological aspects of measurement of pH in EBC (e.g. the effect of ambient CO(2), sample de-aeration, time for pH measurement) require further research. However, EBC pH has not been evaluated prospectively as a guide for treatment, in a manner similar to exhaled NO and sputum eosinophils. EBC represents a simple and totally non-invasive procedure that may contribute towards our understanding of asthma pathophysiology. Besides the evaluation of new biomarkers, the standardization of the already existing procedures is warranted for the introduction of EBC in clinical practice.

Role of exhaled breath biomarkers in environmental health science

As a discipline of public health, environmental health science is the study of the linkage from environmental pollution sources to eventual adverse health outcome. This progression may be divided into two components, (1) "exposure assessment," which deals with the source terms, environmental transport, human exposure routes, and internal dose, and (2) "health effects," which deals with metabolism, cell damage, DNA changes, pathology, and onset of disease. The primary goal of understanding the linkage from source to health outcome is to provide the most effective and efficient environmental intervention methods to reduce health risk to the population. Biomarker measurements address an individual response to a common external environmental stressor. Biomarkers are substances within an individual and are subdivided into chemical markers, exogenous metabolites, endogenous response chemicals, and complex adducts (e.g., proteins, DNA). Standard biomarker measurements are performed in blood, urine, or other biological media such as adipose tissue and lavage fluid. In general, sample collection is invasive, requires medical personnel and a controlled environment, and generates infectious waste. Exploiting exhaled breath as an alternative or supplement to established biomarker measurements is attractive primarily because it allows a simpler collection procedure in the field for numerous individuals. Furthermore, because breath is a gas-phase matrix, volatile biomarkers become more readily accessible to analysis. This article describes successful environmental health applications of exhaled breath and proposes future research directions from the perspective of U.S. Environmental Protection Agency (EPA) human exposure research.

Biomarkers in exhaled breath condensate: a review of collection, processing and analysis

Exhaled breath condensate (EBC) is a potential rich source for countless biomarkers that can provide valuable information about respiratory as well as systemic diseases. EBC has been studied in a variety of diseases including allergic rhinitis, asthma, chronic obstructive lung disease, cystic fibrosis, lung cancer, and obstructive sleep apnea syndrome. Although numerous biomarkers have been discovered and studied in EBC, the methods of collection and biomarker detection have not been fully standardized. While leaving standardization methods up to individual labs for the present time is optimal for the continued discovery of new biomarkers in EBC, this decreases the reproducibility and generalizability of the findings. In this review we will discuss specific biomarkers studied in specific diseases as well as some of the related technical issues including collection, processing and analysis.

Comparison of the anti-inflammatory effects of extra-fine hydrofluoroalkane-beclomethasone vs fluticasone dry powder inhaler on exhaled inflammatory markers in childhood asthma

BACKGROUND

Extra-fine hydrofluoroalkane-beclomethasone differs from other inhaled corticosteroids by its fine aerosol characteristics. Therefore, extra-fine hydrofluoroalkane-beclomethasone may be particularly useful for treating peripheral airway inflammation in asthma.

OBJECTIVE

To analyze the anti-inflammatory effects of extra-fine hydrofluoroalkane-beclomethasone vs fluticasone dry powder inhaler (DPI) in asthmatic children by measuring bronchial and alveolar nitric oxide (NO) and inflammatory markers in exhaled breath condensate (EBC).

METHODS

In a 6-month crossover study, 33 children aged 6 to 12 years with moderate persistent asthma were randomly treated with extra-fine hydrofluoroalkane-beclomethasone (200 microg daily via an Autohaler) and fluticasone DPI (200 microg daily via a Diskus). The primary outcome variables were alveolar NO concentration and bronchial NO flux. The secondary outcome variables were levels of inflammatory markers in EBC, lung function indices, symptoms, exacerbations, and adverse effects. All the variables were recorded at baseline and after each treatment period.

RESULTS

Mean +/- SE alveolar NO concentration and bronchial NO flux were comparable after treatment with hydrofluoroalkane-beclomethasone vs fluticasone DPI (4.7 +/- 0.5 vs 4.3 +/- 0.5 ppb, P = .55, and 1,124.3 +/- 253.6 vs 1,029.1 +/- 195.5 pL/s, P = .70, respectively). In addition, levels of inflammatory markers in EBC, lung function indices, and symptoms did not differ between treatments. Patients used fewer beta2-agonists during the last 2 weeks of hydrofluoroalkane-beclomethasone treatment.

CONCLUSION

The anti-inflammatory effects of hydrofluoroalkane-beclomethasone are similar to those of fluticasone DPI in children with moderate persistent asthma.

Exhaled breath analysis: novel approach for early detection of lung cancer

Lung cancer is a leading cause of cancer death, with the prognosis adversely affected by late diagnosis. Early diagnosis of lung cancer is desirable, but current evidence does not support the application of screening with techniques such as chest radiography, sputum cytology or computed tomography. Breath analysis, which includes gaseous phase analysis that measures volatile organic compounds using electronic noses, exhaled nitric oxide, and exhaled breath condensate (EBC), has been proposed as a non-invasive and simple technique to investigate neoplastic processes in the airways. EBC can be easily collected by breathing into a cooling system that condenses the water vapour in the breath. EBC has already been demonstrated to be useful in investigating inflammatory and oxidative stress changes in various respiratory conditions as it contains measurable mediators of airway inflammation and oxidative stress markers. Furthermore, EBC has also been shown to be a useful method to monitor severity of diseases such as asthma and to act as a surrogate measure of compliance to medical therapy. Presently, there still remains a relative paucity of lung cancer research involving EBC. However, since EBC is a simple, non-invasive technique that can be easily performed, even in ill patients, it has the potential to be validated for use in screening for the early diagnosis of lung cancer.

Exhaled breath condensate: an overview

Exhaled breath condensate (EBC) is a promising source of biomarkers of lung disease. EBC is not a biomarker, but rather a matrix in which biomarkers may be identified, in that way equivalent to blood, sweat, tears, urine, and saliva. EBC may be thought of either as a body fluid or as a condensate of exhaled gas. The field of EBC research has advanced gradually, with the debates surrounding an emerging field helping to pose questions and gradually leading to answers. Conscientious assay technique will likely find in EBC any substance of substantially high enough concentration in the airway lining fluid.

Influence of condensing equipment and temperature on exhaled breath condensate pH, total protein and leukotriene concentrations

BACKGROUND

Exhaled breath condensate analysis is an attractive but still not fully standardised method for investigating airway pathology. Adherence of biomarkers to various condensing surfaces and changes in condensing temperature has been considered to be responsible for the variability of the results. Our aims were to compare the efficacy of different types of condensers and to test the influence of condensing temperature on condensate composition.

METHODS

Breath condensates from 12 healthy persons were collected in two settings: (1) by using three condensers of different type (EcoScreen, R-Tube, Anacon) and (2) by using R-Tube condenser either cooled to -20 or -70 degrees C. Condensate pH at standardised CO(2) level was determined; protein content was measured by the Bradford method and leukotrienes by EIA.

RESULTS

Breath condensates collected using EcoScreen were more alkaline (6.45+/-0.20 vs. 6.19+/-0.23, p<0.05 and 6.10+/-0.26, p<0.001) and contained more protein (3.89+/-2.03 vs. 2.65+/-1.98, n.s. and 1.88+/-1.99 microg/ml, p<0.004) as compared to the other devices. Only parameters obtained with R-Tube and Anacon correlated. Condensing temperature affected condensate pH (5.99+/-0.20 at -20 degrees C and 5.82+/-0.07 at -70 degrees C, p<0.05) but not protein content. Leukotriene B(4) was not found in any sample and cysteinyl-leukotriene was not found in condensates collected with R-Tube or Anacon.

CONCLUSION

Condenser type influences sample pH, total protein content and cysteinyl-leukotriene concentration. Condensing temperature influences condensate pH but not total protein content. These results suggest that adherence of the biomarkers to condenser surface and condensing temperature may play a role but does not fully explain the variability of EBC biomarker levels.

Anti-inflammatory approaches to cystic fibrosis airways disease

PURPOSE OF REVIEW

Therapy aimed at combating excessive lung inflammation should benefit patients with cystic fibrosis. This article reviews anti-inflammatory strategies, focusing on new evidence published since 2006.

RECENT FINDINGS

Use of oral corticosteroids was associated with benefit in an epidemiological study but they are still not recommended; high dose inhaled corticosteroids may cause harm (effect on growth), but they can safely be withdrawn in many patients. Some small beneficial effect of ibuprofen was seen in a multicentre study, but it is unlikely that this will change practice. Altering the imbalance seen in fatty acid metabolism with omega3 polyunsaturated fatty acid supplementation may be helpful but therapeutic benefit is not yet proven. Combating cysteinyl leukotrienes has potential but benefit remains to be proved. The beneficial effect of macrolides has been confirmed in patients with milder disease, but caution is needed because of emerging resistance patterns. Renewed research interest in antiproteases has not demonstrated any significant benefit.

SUMMARY

The ideal therapeutic drug, with the optimal balance of benefit and harm, is not yet available.

Exhaled nitric oxide and biomarkers in exhaled breath condensate indicate the presence, severity and control of childhood asthma

BACKGROUND

Exhaled nitric oxide and inflammatory biomarkers in exhaled breath condensate may be useful to diagnose and monitor childhood asthma. Their ability to indicate an asthma diagnosis, and to assess asthma severity and control, is largely unknown.

OBJECTIVE

To study (1) the ability of exhaled nitric oxide and inflammatory markers in exhaled breath condensate (nitrite, nitrate, hydrogen peroxide, 8-isoprostane, IFN-gamma, TNF-alpha, IL-2, -4, -5, -10 and acidity) to discriminate between childhood asthma and controls. (2) The ability of these biomarkers to indicate asthma severity and control.

METHODS

One-hundred and fourteen children were included: 64 asthmatics (10.7+/-3.0 years, 67.2% atopic) and 50 controls (10.0+/-0.4 years). Condensate was collected using a glass condenser.

RESULTS

Exhaled nitric oxide, IFN-gamma and IL-4 in exhaled breath condensate differed significantly between asthma and controls. Multivariate backward logistic regression models demonstrated that IL-4 (odds ratio 7.9, 95% confidence interval 1.2-51.0) was the only significant indicator of an asthma diagnosis. Asthma control was best assessed by exhaled nitric oxide, 8-isoprostane, IFN-gamma and IL-4 (sensitivity 82%, specificity 80%, P<0.05), whereas exhaled nitric oxide, 8-isoprostane, nitrate and nitrite in condensate were the best indicators of asthma severity (sensitivity 89%, specificity 72%, P<0.05).

CONCLUSION

Different markers in condensate are of an additional value to exhaled nitric oxide, and are needed in non-invasive inflammometry. They could be useful to diagnose asthma and to indicate asthma control and severity in childhood.

Sputum biomarkers of inflammation in cystic fibrosis lung disease

Pulmonary biomarkers are being used more frequently to monitor disease activity and evaluate response to treatment in individuals with cystic fibrosis (CF). This article summarizes the current state of knowledge of biomarkers of inflammation relevant to CF lung disease, and the tools to measure inflammation, with specific emphasis on sputum. Sputum is a rich, noninvasive source of biomarkers of inflammation and infection. Sputum induction, through the inhalation of hypertonic saline, has expanded the possibilities for monitoring airway inflammation and infection, especially in individuals who do not routinely expectorate sputum. We critically examine the existing data supporting the validity of sputum biomarkers in CF, with an eye toward their application as surrogate endpoints or outcome measures in CF clinical trials. Further validation studies are needed regarding the variability of inflammatory biomarker measurements, and to evaluate how these biomarkers relate to disease severity, and to longitudinal changes in lung function and other clinical endpoints. We highlight the need to incorporate sputum collection, by induction if necessary, and measurement of sputum biomarkers into routine CF clinical care. In the future, pulmonary biomarkers will likely be useful in predicting disease progression, indicating the onset and resolution of a pulmonary exacerbation, and assessing response to current therapies or candidate therapeutics.

Cytokines and other immunological biomarkers in children's environmental health studies

Environmental exposures (e.g. pesticides, air pollution, and environmental tobacco smoke) during prenatal and early postnatal development have been linked to a growing number of childhood diseases including allergic disorders and leukemia. Because the immune response plays a critical role in each of these diseases, it is important to study the effects of toxicants on the developing immune system. Children's unique susceptibility to environmental toxicants has become an important focus of the field of immunotoxicology and the use of immune biomarkers in molecular epidemiology of children's environmental health is a rapidly expanding field of research. In this review, we discuss how markers of immune status and immunotoxicity are being applied to pediatric studies, with a specific focus on the various methods used to analyze T-helper-1/2 (Th1/Th2) cytokine profiles. Furthermore, we review recent data on the effects of children's environmental exposures to volatile organic compounds, metals, and pesticides on Th1/Th2 cytokine profiles and the associations of Th1/Th2 profiles with adverse health outcomes such as pediatric respiratory diseases, allergies, cancer and diabetes. Although cytokine profiles are increasingly used in children's studies, there is still a need to acquire distribution data for different ages and ethnic groups of healthy children. These data will contribute to the validation and standardization of cytokine biomarkers for future studies. Application of immunological markers in epidemiological studies will improve the understanding of mechanisms that underlie associations between environmental exposures and immune-mediated disorders.

Are exhaled breath condensates useful in monitoring asthma?

Exhaled breath condensate (EBC) has emerged as a novel noninvasive technique for assessment of airway inflammation, and it also provides useful information on the airway lining fluid composition. Examples of markers that can be identified in the EBC of patients with asthma include pH, eicosanoids, nitrogen oxides and related products, markers of oxidative stress, certain cytokines, chemokines, and growth factors. There is some evidence that certain markers in EBC differ between patients with asthma and controls, and some markers may correlate with asthma severity and lung function, but there are many methodologic pitfalls with EBC assessment that limit its clinical applicability at present. More studies are needed before this technique can be recommended for clinical use.