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

Inflammatory markers in exhaled breath condensate in nonasthmatic children with food allergy

Allergy is a systemic inflammation; therefore, although the allergic symptom may be seen in a specific organ system, the effects of this inflammation may be seen in other organs. interleukin (IL) IL4, IL5 and IL13 are the major Th2 cytokines and e-cadherin is an epithelial barrier protein. The objective of this research was to assess indicators of inflammation specific to Th2 responses and proteins related to the protective barrier of the airway's inner lining. These assessments were conducted using exhaled breath condensate (EBC), which provides insights into peripheral airway conditions of children suffering from food allergies. The study had 24 patients with food allergy and 24 control individuals younger than three years of age with no history of food reaction. The diagnosis of food allergy was based on food allergen-specific IgE and skin prick test positivity in our clinic and oral food testing in selected cases. EBC samples were obtained by Ecoscreen (Jaegar, Hoechberg, Germany). IL4, IL5, IL13 and E-cadherin levels were measured in these samples by enzyme linked immunoassay. The group of children with food allergies, consisting mainly of 14 girls, had a median age of 16 months, whereas the control group, which included 11 girls, had a median age of 15 months (p= 0.89). Comparing the two groups, children with food allergies exhibited notably lower levels of IL-13 in the EBC compared to the control group (median values of 59.14 and 76.36, respectively,p= 0.02). Conversely, the concentration of IL-4 in the EBC was significantly higher in children with food allergies (median values of 1.94 and 1.29, respectively,p= 0.003). However, the levels of IL-5 and e-cadherin showed no significant differences between the two groups (withp-values of 0.74 and 0.09, respectively) as shown in table1. High level of IL-4 despite the low level of IL-13 in the EBC of children having food allergy may be indicative of an early inflammatory phase that is not yet in the effector phase. Studies about the evolution of this process later in life are needed to assess the role of airway inflammation in children with food allergy who develop asthma.

Exhaled Breath Condensate: A Non-Invasive Source for Tracking of Genetic and Epigenetic Alterations in Lung Diseases

Lung diseases have been recognized as an extensive cause of morbidity and mortality in the worldwide. The high degree of clinical heterogeneity and nonspecific initial symptoms of lung diseases contribute to a delayed diagnosis. So, the molecular and genomic profiling play a pivotal role in promoting the pulmonary diseases. Exhaled breath condensate (EBC) as a novel and potential method for sampling the respiratory epithelial lining fluid is to assess the inflammatory and oxidative stress biomarkers, drugs and genetic alterations in the pathophysiologic processes of lung diseases. The recent studies on the analysis of EBC from both a genetic and epigenetic point of view were searched from database and reviewed. This review provides an overview of the current findings in the tracking of genomic and epigenetic alterations which are potentially effective in better management of cancer detection. In addition, respiratory microbiota DNA using EBC samples in association with pulmonary disease especially lung cancer were investigated. Various studies have concluded that EBC has a great potential for analysis of nuclear and mitochondrial DNA alterations as well as epigenetic modifications and identification of respiratory microbiome. Next-generation sequencing (NGS) based genomic profiling of EBC samples is recommended as a promising approach to establish personalized based prevention, diagnosis, treatment and post-treatment follow-ups for patients with lung diseases especially lung cancer.

Exhaled breath analysis in the diagnosis of head and neck cancer

Head and neck cancer (HNC) comprises a heterogeneous group of upper aerodigestive tract malignant neoplasms, the most frequent of which is squamous cell carcinoma. HNC forms the eighth most common cancer type and the incidence is increasing. However, survival has improved only moderately during the past decades. Currently, early diagnosis remains the mainstay for improving treatment outcomes in this patient population. Unfortunately, screening methods to allow early detection of HNC are not yet established. Therefore, many cases are still diagnosed at advanced stage, compromising outcomes. Exhaled breath analysis (EBA) is a diagnostic tool that has been recently introduced for many cancers. Breath analysis is non-invasive, cost-effective, time-saving, and can potentially be applied for cancer screening. Here, we provide a summary of the accumulated evidence on the feasibility of EBA in the diagnosis of HNC.

Measuring acute pulmonary responses to occupational wildland fire smoke exposure using exhaled breath condensate

Wildland firefighters are directly exposed to elevated levels of wildland fire (WF) smoke. Although studies demonstrate WF smoke exposure is associated with lung function changes, few studies that use invasive sample collection methods have been conducted to investigate underlying biochemical changes. These methods are also either unrepresentative of the deeper airways or capable of inducing inflammation. In the present study, levels of biomarkers of oxidative stress (8-isoprostane) and pro-inflammatory response (interleukin-6 [IL-6], interleukin-8 [IL-8], C-reactive protein [CRP], and soluble intercellular adhesion molecule-1 [sICAM-1]) were determined in exhaled breath condensate (EBC) samples that were collected from firefighters before, after, and next morning following prescribed burn and regular work shifts. Results show only a marginal cross-shift increase in 8-isoprostane on burn days (.05 < p value < .1), suggesting WF smoke exposure causes mild pulmonary responses.

Biomarkers for Recurrent Wheezing and Asthma in Preschool Children

Wheezing is one of the characteristic symptoms of asthma, but all preschool children with wheezing are not diagnosed with asthma. Preschool children are not cooperative enough to participate in spirometry and invasive tests. Thus, there is no conventional method to diagnose asthma in preschool children. We reviewed studies on non-invasive biomarkers for assessing asthma in preschool children. Specimens that can be easily obtained by non-invasive methods are blood, exhaled breath and urine. Eosinophils, eosinophil cationic protein and eosinophil-derived neurotoxin (EDN) in blood are helpful in evaluating eosinophilic inflammation of the airways. Exhaled breath contains nitric oxide, volatile organic compounds, various cytokines and mediators as analytical components. Fraction of exhaled nitric oxide has been used to assess the degree of eosinophil inflammation and has been standardized in school-age children and adults, but not yet in preschool children. Exhaled breath condensate (EBC) pH and various cytokines/mediators that are detected in EBC seem to be promising biomarkers for assessing asthma, but need more standardization and validation. There are several biomarkers useful for assessing asthma, but none are ideal. Some biomarkers need standardized methods of obtaining samples from uncooperative preschool children for clinical use and require sufficient validation. Recently, another activated eosinophil marker, serum EDN, has shown promising results as a biomarker for recurrent wheezing and asthma in preschool children.

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."

Inhaled corticosteroids do not reduce initial high activity of matrix metalloproteinase (MMP)-9 in exhaled breath condensates of children with asthma exacerbation: a proof of concept study

Inhaled corticosteroids (ICS) are the key component of asthma treatment. However, it is unclear whether they could control the activity and level of matrix metalloproteinase (MMP)-9, which is an important factor in asthma-associated inflammation and airway remodeling. Therefore, the aim of this proof of concept study was to analyze the influence of increased doses of ICS on MMP-9 in exhaled breath condensates (EBC) of patients with allergic asthma exacerbation. Apart from MMP-9, the assessment concerned selected inflammation markers – exhaled nitric oxide (eNO) and cytokines (IL-8 and TNF).

The study involved a small group (n = 4) of individuals with asthma exacerbation. The intervention concerned increased doses of ICS with β-mimetics for 4 weeks. In addition to clinical evaluation, eNO measurements and EBC collections were done before and after 4 weeks of intense ICS treatment. The biochemical assessment of EBC concerned MMP-9, IL-8 and TNF. The data were compared to results of healthy controls (n = 6).

The initial levels of eNO, MMP-9 and TNF in EBC were higher in the asthma group than in controls. In all subjects IL-8 levels were below the detection limit. After 4 weeks of ICS treatment in all patients we observed improvement of clinical and laboratory parameters. Interestingly, despite reduction of eNO and TNF, the activity of MMP-9/EBC remained on the initial level.

Practical relevance of our results is limited by a small group. Nevertheless, our data suggest that ICS, although sufficient to control symptoms and inflammatory markers, may be ineffective to reduce MMP-9/EBC activity in asthma exacerbation and, possibly, airway remodeling.

Exhaled breath condensate for lung cancer protein analysis: a review of methods and biomarkers

Lung cancer is a leading cause of cancer-related deaths worldwide, and is considered one of the most aggressive human cancers, with a 5 year overall survival of 10-15%. Early diagnosis of lung cancer is ideal; however, it is still uncertain as to what technique will prove successful in the systematic screening of high-risk populations, with the strongest evidence currently supporting low dose computed tomography (LDCT). Analysis of exhaled breath condensate (EBC) has recently been proposed as an alternative low risk and non-invasive screening method to investigate early-stage neoplastic processes in the airways. However, there still remains a relative paucity of lung cancer research involving EBC, particularly in the measurement of lung proteins that are centrally linked to pathogenesis. Considering the ease and safety associated with EBC collection, and advances in the area of mass spectrometry based profiling, this technology has potential for use in screening for the early diagnosis of lung cancer. This review will examine proteomics as a method of detecting markers of neoplasia in patient EBC with a particular emphasis on LC, as well as discussing methodological challenges involving in proteomic analysis of EBC specimens.

Biomarkers in Exhaled Breath Condensate Are Not Predictive for Pulmonary Exacerbations in Children with Cystic Fibrosis: Results of a One-Year Observational Study

Background

Cystic Fibrosis (CF) is characterized by chronically inflamed airways, and inflammation even increases during pulmonary exacerbations. These adverse events have an important influence on the well-being, quality of life, and lung function of patients with CF. Prediction of exacerbations by inflammatory markers in exhaled breath condensate (EBC) combined with early treatment may prevent these pulmonary exacerbations and may improve the prognosis.

Aim

To investigate the diagnostic accuracy of a set of inflammatory markers in EBC to predict pulmonary exacerbations in children with CF.

Methods

In this one-year prospective observational study, 49 children with CF were included. During study visits with an interval of 2 months, a symptom questionnaire was completed, EBC was collected, and lung function measurements were performed. The acidity of EBC was measured directly after collection. Inflammatory markers interleukin (IL)-6, IL-8, tumor necrosis factor α (TNF-α), and macrophage migration inhibitory factor (MIF) were measured using high sensitivity bead based flow immunoassays. Pulmonary exacerbations were recorded during the study and were defined in two ways. The predictive power of inflammatory markers and the other covariates was assessed using conditionally specified models and a receiver operating characteristic curve (SAS version 9.2). In addition, k-nearest neighbors (KNN) algorithm was applied (SAS version 9.2).

Results

Sixty-five percent of the children had one or more exacerbations during the study. The conditionally specified models showed an overall correct prediction rate of 55%. The area under the curve (AUC) was equal to 0.62. The results obtained with the KNN algorithm were very similar.

Conclusion

Although there is some evidence indicating that the predictors outperform random guessing, the general diagnostic accuracy of EBC acidity and the EBC inflammatory markers IL-6, IL-8, TNF-α and MIF is low. At present it is not possible to predict pulmonary exacerbations in children with CF with the chosen biomarkers and the method of EBC analysis. The biochemical measurements of EBC markers should be improved and other techniques should be considered.

Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

Biomarkers to predict asthma in wheezing preschool children

Wheezing in preschool children is a very common symptom. An adequate prediction of asthma in these children is difficult and cannot be reliably assessed with conventional clinical tools. The study of potential predictive biomarkers in various media, ranging from invasive sampling (e.g. bronchoscopy) to non-invasive sampling (lung function testing and exhaled breath analysis), was comprehensively reviewed. The evolution in biomarker discovery has resulted in an 'omics' approach, in which hundreds of biomarkers in the field of genomics, proteomics, metabolomics, and 'breath-omics' can be simultaneously studied. First, results on gene expression and exhaled breath profiles in predicting an early asthma diagnosis are promising. However, many hurdles need to be overcome before clinical implementation is possible. To reliably predict asthma in a wheezing child, probably a holistic approach is needed, combining clinical information with blood sampling, lung function tests, and potentially exhaled breath analysis. The further development of predictive, non-invasive biomarkers may eventually improve an early asthma diagnosis in wheezing preschool children and assist clinicians in early treatment decision-making.

IL-5, IL-8 and MMP -9 levels in exhaled breath condensate of atopic and nonatopic asthmatic children

RATIONALE

Asthma is a heterogeneous disease, and a great majority of pediatric patients with asthma demonstrate atopic characteristics and develop a Th2 type cytokine response. Nonatopic asthma, on the other hand, is seen more rarely.

METHODS

In this study, levels of IL-5, IL-8 and MMP-9 were measured in exhaled breath condensate (EBC) of the subjects to demonstrate the extent of tissue damage as well as eosinophilic and neutrophilic inflammation in children with atopic and nonatopic asthma. A total of 37 children with atopic asthma and 37 children with nonatopic asthma were enrolled in the study. Patients who exhibited protease positive aeroallergen (House dust mite, mould mix, olea, grass mix) sensitivity in allergen skin prick test were included in the atopic asthma group. To evaluate the EBC, the fluid content of the breath was collected by having the patients exhale into an EBC device, after which the IL-5, IL-8 and MMP-9 levels were assayed using the ELISA method.

RESULTS

The atopic asthmatics exhibited significantly higher IL-5 levels in their EBC samples than the nonatopic asthmatics (0.271 [0.198-0.489] pg/ml and 0.198 [0.125-0.344] pg/ml, respectively, p = 0.04), while no significant differences were observed in the levels of IL-8 and MMP-9 in the EBC samples of the atopic and nonatopic asthmatics.

CONCLUSIONS

IL-5 levels, as a marker of eosinophilic inflammation, were demonstrated to be higher in the children with atopic asthma when compared to those with nonatopic asthma in EBC. The fact that no significant difference was apparent in the IL-8 levels between the groups suggests that it is the severity of the disease rather than the atopic state that plays an important role in IL-8 levels. Since no difference was recorded between the groups in terms of MMP-9 levels, lung damage in asthma sufferers seems to develop independent of atopia.

Exhaled biomarkers and gene expression at preschool age improve asthma prediction at 6 years of age

RATIONALE

A reliable asthma diagnosis is difficult in wheezing preschool children.

OBJECTIVES

To assess whether exhaled biomarkers, expression of inflammation genes, and early lung function measurements can improve a reliable asthma prediction in preschool wheezing children.

METHODS

Two hundred two preschool recurrent wheezers (aged 2-4 yr) were prospectively followed up until 6 years of age. At 6 years of age, a diagnosis (asthma or transient wheeze) was based on symptoms, lung function, and asthma medication use. The added predictive value (area under the receiver operating characteristic curve [AUC]) of biomarkers to clinical information (assessed with the Asthma Predictive Index [API]) assessed at preschool age in diagnosing asthma at 6 years of age was determined with a validation set. Biomarkers in exhaled breath condensate, exhaled volatile organic compounds (VOCs), gene expression, and airway resistance were measured.

MEASUREMENTS AND MAIN RESULTS

At 6 years of age, 198 children were diagnosed (76 with asthma, 122 with transient wheeze). Information on exhaled VOCs significantly improved asthma prediction (AUC, 89% [increase of 28%]; positive predictive value [PPV]/negative predictive value [NPV], 82/83%), which persisted in the validation set. Information on gene expression of toll-like receptor 4, catalase, and tumor necrosis factor-α significantly improved asthma prediction (AUC, 75% [increase of 17%]; PPV/NPV, 76/73%). This could not be confirmed after validation. Biomarkers in exhaled breath condensate and airway resistance (pre- and post- bronchodilator) did not improve an asthma prediction. The combined model with VOCs, gene expression, and API had an AUC of 95% (PPV/NPV, 90/89%).

CONCLUSIONS

Adding information on exhaled VOCs and possibly expression of inflammation genes to the API significantly improves an accurate asthma diagnosis in preschool children. Clinical trial registered with www.clinicaltrial.gov (NCT 00422747).

Single-breath analysis using a novel simple sampler and capillary electrophoresis with contactless conductometric detection

The analysis of ionic content of exhaled breath condensate (EBC) from one single breath by CE with C(4) D is demonstrated for the first time. A miniature sampler made from a 2-mL syringe and an aluminum cooling cylinder for collection of EBC was developed. Various parameters of the sampler that influence its collection efficiency, repeatability, and effect of respiratory patterns were studied in detail. Efficient procedures for the cleanup of the miniature sampler were also developed and resulted in significant improvement of sampling repeatability. Analysis of EBC was performed by CE-C(4) D in a 60 mM MES/l-histidine BGE with 30 μM CTAB and 2 mM 18-crown-6 at pH 6 and excellent repeatability of migration times (RSD < 1.3% (n = 7)) and peak areas (RSD < 7% (n = 7)) of 12 inorganic anions, cations, and organic acids was obtained. It has been shown that the breathing pattern has a significant impact on the concentration of the analytes in the collected EBC. As the ventilatory pattern can be easily controlled during single exhalation, the developed collection system and method provides a highly reproducible and fast way of collecting EBC with applicability in point-of-care diagnostics.

Nitric oxide, IL-6 and IL-13 are increased in the exhaled breath condensates of children with allergic rhinitis

AIM

To evaluate nitric oxide and interleukin (IL)-6, IL-8 and IL-13 in the exhaled breath of children with allergic rhinitis (AR), before and after intranasal allergen exposure.

METHODS

A total of 49 children with AR – comprising 20 who also had episodic asthma (AR+A) and 29 without asthma (AR) – were compared with 34 healthy controls. Nitric oxide concentrations in exhaled air (eNO) and IL-6, IL-8 and IL-13 in exhaled breath condensates (EBC) were measured in winter, outside the natural allergen exposure season, before and after an intranasal allergen challenge.

RESULTS

The mean concentrations of eNO, IL-6 and IL-13 were significantly higher in the two AR groups. The concentration of IL-8 was below the assay detection limit in all EBC samples. The intranasal allergen challenge increased IL-13/EBC levels in both AR groups, but did not influence mean concentrations of eNO, IL-6 or IL-8. No challenge-related changes in IL-13/EBC were observed in the allergen-exposed controls or placebo-exposed children.

CONCLUSION

Despite local application, the intranasal allergen challenge increased IL-13/EBC concentration in the AR children. As EBC reflects the status of lower airway segments, our observation may support the 'united airways' hypothesis, suggesting a functional link between the upper and lower airways.

Integrative genomic analysis identifies a role for intercellular adhesion molecule 1 in childhood asthma

BACKGROUND

Childhood asthma is characterized by chronic airway inflammation. Integrative genomic analysis of airway inflammation on genetic and protein level may help to unravel mechanisms of childhood asthma. We aimed to employ an integrative genomic approach investigating inflammation markers on DNA, mRNA, and protein level at preschool age in relationship to asthma development.

METHODS

In a prospective study, 252 preschool children (202 recurrent wheezers, 50 controls) from the Asthma DEtection and Monitoring (ADEM) study were followed until the age of six. Genetic variants, mRNA expression in peripheral blood mononuclear cells, and protein levels in exhaled breath condensate for intercellular adhesion molecule 1 (ICAM1), interleukin (IL)4, IL8, IL10, IL13, and tumor necrosis factor α were analyzed at preschool age. At six years of age, a classification (healthy, transient wheeze, or asthma) was based on symptoms, lung function, and medication use.

RESULTS

The ICAM1 rs5498 A allele was positively associated with asthma development (p = 0.02) and ICAM1 gene expression (p = 0.01). ICAM1 gene expression was positively associated with exhaled levels of soluble ICAM1 (p = 0.04) which in turn was positively associated with asthma development (p = 0.01). Furthermore, rs1800872 and rs1800896 in IL10 were associated with altered IL10 mRNA expression (p < 0.01). Exhaled levels of IL4, IL10, and IL13 were positively associated with asthma development (p < 0.01).

CONCLUSIONS

In this unique prospective study, we demonstrated that ICAM1 is associated with asthma development on DNA, mRNA, and protein level. Thus, ICAM1 is likely to be involved in the development of childhood asthma.

Biomarkers in Exhaled Breath Condensate and Serum of Chronic Obstructive Pulmonary Disease and Non-Small-Cell Lung Cancer

Chronic obstructive pulmonary disease (COPD) and lung cancer are leading causes of deaths worldwide which are associated with chronic inflammation and oxidative stress. Lung cancer, in particular, has a very high mortality rate due to the characteristically late diagnosis. As such, identification of novel biomarkers which allow for early diagnosis of these diseases could improve outcome and survival rate. Markers of oxidative stress in exhaled breath condensate (EBC) are examples of potential diagnostic markers for both COPD and non-small-cell lung cancer (NSCLC). They may even be useful in monitoring treatment response. In the serum, S100A8, S100A9, and S100A12 of the S100 proteins are proinflammatory markers. They have been indicated in several inflammatory diseases and cancers including secondary metastasis into the lung. It is highly likely that they not only have the potential to be diagnostic biomarkers for NSCLC but also prognostic indicators and therapeutic targets.

Increased cys-leukotrienes in exhaled breath condensate and decrease of PNIF after intranasal allergen challenge support the recognition of allergic rhinitis in children

Exhaled breath condensate (EBC) contains various mediators of inflammation. Since their concentrations correlate with severity of inflammatory response, EBC assessment allows non-invasive detection of various respiratory tract diseases and enables monitoring of their progression or treatment effectiveness. In this study, authors evaluate the usefulness of cysteinyl leukotrienes (cysLT) measurement in EBC, as non-invasive diagnostic markers of allergic rhinitis in children. It has been found that the assessment of cysLT in EBC, when performed out of the natural allergen exposure, can discriminate between healthy and allergic rhinitis individuals, with sensitivity 87.8% and specificity 76.4%, at the threshold level 39.05 pg/ml. The change of peak nasal inspiratory flow (ΔPNIF), measured before and after intranasal allergen challenge allowed recognition of healthy/allergic rhinitis-suffering individuals with sensitivity 76.8% and specificity 78.6%, at the threshold level of -3.2 l/min. When ΔPNIF assessment was combined with the measurement of cysLT in EBC, the sensitivity of such diagnostic approach reached 100% and its specificity increased up to 84.6%. The proposed algorithm was found to sufficiently discriminate between allergic rhinitis-suffering and healthy children, however, its clinical usefulness especially in young children requires further studies.

Predicting persistence of asthma in preschool wheezers: crystal balls or muddy waters?

Since preschool wheezing is the common expression of several heterogeneous disorders, identification of children at risk for persistent asthma is particularly challenging. To date, efforts to predict the outcome of preschool wheeze have mainly relied on predictive rules consisting of simple clinical and laboratory parameters. Among these tools, the asthma predictive index (API) has been introduced in international guidelines and position papers and is recommended for use in clinical practice. This article reviews the currently available asthma predictive models focusing on their validity and performance characteristics. Although these tools are generally simple and easy to apply, they suffer important intrinsic and practical limitations and they have been insufficiently validated to allow for widespread use in clinical settings. We also present evidence that their ability to predict the long-term outcome of preschool wheeze is limited in general populations, and even poorer in high-risk children in which prediction of asthma persistence might have important clinical and prognostic implications. Due to the complex and multifactorial nature of asthma, prediction of asthma persistence based on simple clinical models is practically impossible.

A motivational interviewing intervention to PREvent PAssive Smoke Exposure (PREPASE) in children with a high risk of asthma: design of a randomised controlled trial

Background

Especially children at risk for asthma are sensitive to the detrimental health effects of passive smoke (PS) exposure, like respiratory complaints and allergic sensitisation. Therefore, effective prevention of PS exposure in this group of vulnerable children is important. Based on previous studies, we hypothesized that an effective intervention program to prevent PS exposure in children is possible by means of a motivational interviewing tailored program with repeated contacts focussing on awareness, knowledge, beliefs (pros/cons), perceived barriers and needs of parents, in combination with feedback about urine cotinine levels of the children. The aim of the PREPASE study is to test the effectiveness of such an intervention program towards eliminating or reducing of PS exposure in children at risk for asthma. This article describes the protocol of the PREPASE study.

Methods

The study is a one-year follow-up randomized controlled trial. Families with children (0–13 years of age) having an asthma predisposition who experience PS exposure at home are randomized into an intervention group receiving an intervention or a control group receiving care as usual. The intervention is given by trained research assistants. The intervention starts one month after a baseline measurement and takes place once per month for an hour during six home based counselling sessions. The primary outcome measure is the percentage of families curtailing PS exposure in children (parental report verified with the urine cotinine concentrations of the children) after 6 months. The secondary outcome measures include: household nicotine level, the child’s lung function, airway inflammation and oxidative stress, presence of wheezing and questionnaires on respiratory symptoms, and quality of life. A process evaluation is included. Most of the measurements take place every 3 months (baseline and after 3, 6, 9 and 12 months of study).

Conclusion

The PREPASE study incorporates successful elements of previous interventions and may therefore be very promising. If proven effective, the intervention will benefit the health of children at risk for asthma and may also create opportunity to be tested in other population.

Trial registration number

NTR2632

Symptoms, but not a biomarker response to inhaled corticosteroids, predict asthma in preschool children with recurrent wheeze

Background. A reliable asthma diagnosis is challenging in preschool wheezing children. As inhaled corticosteroids (ICS) are more effective in asthmatics than in children with transient wheeze, an ICS response might be helpful in early asthma diagnosis. Methods. 175 children (aged two–four years) with recurrent wheeze received 200 μg Beclomethasone extra-fine daily for eight weeks. Changes in Exhaled Breath Condensate (EBC) biomarkers (pH, interleukin (IL)-1α, IL-2, IL-4, IL-5, IL-10, IFN-γ, sICAM, and CCL-11), Fractional exhaled Nitric Oxide (FeNO), airway resistance, and symptoms were assessed. At six years of age a child was diagnosed as transient wheezer or asthmatic. Adjusted logistic regression analysis was performed with multiple testing correction. Results. 106 transient wheezers and 64 asthmatics were analysed at six years of age. Neither changes in EBC biomarkers, nor FeNO, airway resistance, or symptoms during ICS trial at preschool age were related to asthma diagnosis at six years of age. However, asthmatics had more airway symptoms before the start of the ICS trial than transient wheezers (P < 0.01). Discussion. Although symptom score in preschool wheezing children at baseline was associated with asthma at six years of age, EBC biomarkers, airway resistance, or symptom response to ICS at preschool age could not predict asthma diagnosis at six years of age.

Markers of oxidative stress are increased in exhaled breath condensates of children with atopic dermatitis

BACKGROUND

Airway inflammation may be present in subjects affected by atopic dermatitis (AD) but still without asthma symptoms. Exhaled breath condensate (EBC) reflects the composition of bronchoalveolar extracellular lining fluid that contains a large number of mediators of airway inflammation and oxidative damage.

OBJECTIVES

  We assessed inflammatory markers in the EBC of patients with AD. Fifty-six children (34 girls and 22 boys) were enrolled: 33 affected by AD and 23 healthy controls.

METHODS

  EBC was collected using a condenser device. We measured EBC pH and concentrations of leukotriene B4 (LTB4), 8-isoprostane, H(2) O(2) , malondialdehyde and 4-hydroxynoneal. Respiratory resistance was also evaluated.

RESULTS

  EBC pH in patients with AD was significantly lower than in healthy children, median (range) being 8·02 (7·94-8·12) in AD vs. 8·11 (8·05-8·16) (P = 0·02). The values of exhaled 8-isoprostane and LTB4 were significantly increased in subjects with AD compared with normal controls (P < 0·01 and P < 0·001, respectively). There was increased 4-hydroxynoneal in patients with AD but this did not reach statistical significance. Evaluating respiratory resistance, no bronchoreversibility was demonstrated in the children with AD.

CONCLUSIONS

pH, LTB4 and 8-isoprostane in EBC could be sensitive markers of airway inflammation in children with AD. Prospective studies would be of interest to evaluate if airway inflammation, not yet clinically evident, could predict the development of asthma later in life in children with AD.

Impact of bacterial colonization on exhaled inflammatory markers in wheezing preschool children

Wheeze is a common symptom in preschool children. The role of bacteria, regulatory T (T(reg)) cells and their association with airway inflammation in preschool wheeze is largely unknown. We evaluated inflammatory markers in exhaled breath condensate (EBC), bacterial colonization and circulating T(reg) cells in preschool children with and without recurrent wheeze. We recruited 252 children (aged two to four years) with (N = 202) and without (N = 50) recurrent wheeze. EBC was collected using an efficient closed glass condenser. Inflammatory markers in EBC (Interleukin(IL)-2, IL-4, IL-8, IL-10, IL-13) were assessed using multiplex immunoassay. Nasal and throat swabs were analysed for presence of Streptococcus pneumoniae, Haemophilus (para)influenzae and Staphylococcus aureus. Proportions of T(reg) cells (CD4(+)CD25(high)CD127(-)) were quantified by flow cytometry. Recurrent wheezing children had elevated EBC levels of IL-2, IL-4, IL-10 and IL-13 compared to non-wheezers (odds ratio (95% confidence interval): 1.67 (1.23-2.27): 1.58 (1.15-2.18): 1.47 (1.14-1.90): 1.55 (1.16-2.06), p <0.05, respectively). Bacteria were frequently present in children with and without wheeze, with no difference in prevalence (16-52% versus 16-50%, respectively). Moreover, the proportion of T(reg) cells did not differ between both groups. Wheezing children with bacterial colonization did not significantly differ in exhaled levels of inflammatory markers or proportion of T(reg) cells compared to wheezing children without colonization. The analysis of EBC might serve as a helpful non-invasive tool to early assess airway inflammation in wheezing children. The various elevated exhaled inflammatory markers indicate increased airway inflammation in wheezing preschool children. In the presence of wheeze, we found no evidence for bacterial induced airway inflammation.

Molecular and microscopic analysis of bacteria and viruses in exhaled breath collected using a simple impaction and condensing method

Exhaled breath condensate (EBC) is increasingly being used as a non-invasive method for disease diagnosis and environmental exposure assessment. By using hydrophobic surface, ice, and droplet scavenging, a simple impaction and condensing based collection method is reported here. Human subjects were recruited to exhale toward the device for 1, 2, 3, and 4 min. The exhaled breath quickly formed into tiny droplets on the hydrophobic surface, which were subsequently scavenged into a 10 µL rolling deionized water droplet. The collected EBC was further analyzed using culturing, DNA stain, Scanning Electron Microscope (SEM), polymerase chain reaction (PCR) and colorimetry (VITEK 2) for bacteria and viruses.Experimental data revealed that bacteria and viruses in EBC can be rapidly collected using the method developed here, with an observed efficiency of 100 µL EBC within 1 min. Culturing, DNA stain, SEM, and qPCR methods all detected high bacterial concentrations up to 7000 CFU/m(3) in exhaled breath, including both viable and dead cells of various types. Sphingomonas paucimobilis and Kocuria variants were found dominant in EBC samples using VITEK 2 system. SEM images revealed that most bacteria in exhaled breath are detected in the size range of 0.5-1.0 µm, which is able to enable them to remain airborne for a longer time, thus presenting a risk for airborne transmission of potential diseases. Using qPCR, influenza A H3N2 viruses were also detected in one EBC sample. Different from other devices restricted solely to condensation, the developed method can be easily achieved both by impaction and condensation in a laboratory and could impact current practice of EBC collection. Nonetheless, the reported work is a proof-of-concept demonstration, and its performance in non-invasive disease diagnosis such as bacterimia and virus infections needs to be further validated including effects of its influencing matrix.

Elevated inflammatory markers at preschool age precede persistent wheezing at school age

BACKGROUND

  Wheeze is a heterogeneous symptom in preschool children. At preschool age it is hard to predict whether symptoms will pass or persist and develop into asthma. Our objective is to prospectively study whether inflammatory markers in exhaled breath condensate (EBC) and pre- and post-bronchodilator interrupter resistance (Rint) assessed at preschool age, are associated with wheezing phenotypes at school age.

METHODS

  Children (N = 230) were recruited from the Asthma DEtection and Monitoring (ADEM) study. At preschool age [mean (SE): 3.3 (0.1) yr], pre- and post-bronchodilator Rint was assessed. EBC was collected using a closed glass condenser. Inflammatory markers (IL-2, IL-4, IL-8, IL-10, sICAM) were measured using multiplex immunoassay. Wheezing phenotypes at 5 yr of age were determined based on longitudinal assessment. Children were classified as: never (N = 47), early-transient (N = 89) or persistent wheezers (N = 94).

RESULTS

  Persistent wheezers had elevated levels of all interleukins at preschool age compared to children who never wheezed (p < 0.05). EBC markers did not differ between the persistent and transient wheezers. There was no marked difference in Rint between wheezing phenotypes.

CONCLUSIONS

  We demonstrated that 5 yr old children with persistent wheeze already had elevated exhaled inflammatory markers at preschool age compared to never wheezers, indicating augmented airway inflammation in these children.

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.

Can exhaled inflammatory markers predict a steroid response in wheezing preschool children?

BACKGROUND

The efficacy of inhaled corticosteroids (ICS) varies among wheezing preschool children. Currently, it is not possible to predict which fraction of wheezing children will benefit from an ICS treatment.

OBJECTIVE

We explored whether fractional exhaled nitric oxide (FeNO) and inflammatory markers in exhaled breath condensate (EBC) can predict an ICS response in preschool wheezers.

METHODS

An 8-week ICS study (registered at Clinicaltrial.gov: NCT 00422747; 200 μg; beclomethasone extra-fine daily) was performed in 93 wheezing children (age range 2.0-4.4 years). At baseline, FeNO was determined off-line. EBC was collected using a closed glass-condenser. The acidity of EBC was determined and other EBC markers [interleukin (IL)-1α, IL-2, IL-4, IL-5, IL-10, soluble intercellular adhesion molecule, interferon-γ, eotaxin] were measured using a multiplex immunoassay. The change in airway resistance (Rint) and symptom score following ICS treatment was related to atopy (positive Phadiatop Infant test), FeNO and EBC markers.

RESULTS

Airway resistance and symptoms mildly improved after ICS treatment [median (IQR): 1.4 (1.2-1.7) to 1.3 (1.1-1.5) kPa s/L, symptom score: 26 (23-28) to 28 (24-29), P < 0.01, respectively]. Only IL-10 and atopy had limited predictive value regarding a change in symptoms [β (SE) =-0.13 (0.07), P = 0.08, β (SE) = 2.05 (1.17), P = 0.08, respectively].

CONCLUSIONS AND CLINICAL RELEVANCE

We did not find convincing evidence that FeNO and EBC markers could predict an ICS response in preschool wheezers. Recommendations for future studies on this topic are given.

Reduced breath condensate pH in asymptomatic children with prior wheezing as a risk factor for asthma

BACKGROUND

Early noninvasive detection of increased risk of asthma with exhaled breath condensate (EBC) pH measurement has not been applied to preschool children.

OBJECTIVE

We sought to evaluate the ability of EBC pH measurement to identify young asymptomatic children at risk of asthma using the combination of recurrent wheezing and atopic sensitization as a proxy for a high risk of asthma.

METHODS

pH values were measured in deaerated EBC from 191 children (median age, 4.4 years [interquartile range, 2.2 years]). Children were divided into one of 5 groups: asymptomatic children with recurrent wheezy bronchitis with (group 1, n = 34) or without (group 2, n = 64) allergic sensitization, acute wheezy bronchitis (group 3, n = 18), allergic rhinoconjunctivitis without recurrent wheezy bronchitis (group 4, n = 15), and healthy control subjects (group 5, n = 60). The Asthma Predictive Index score was calculated for groups 1 and 2. Statistical significance was evaluated with the appropriate nonparametric tests, and the discriminatory accuracy was evaluated with receiver operating characteristic analysis.

RESULTS

Deaerated EBC pH values were significantly lower in groups 1 and 3 than in groups 2, 4, and 5 (median, 7.49 [interquartile range, 0.94] and 7.44 [interquartile range, 0.70] vs 7.93 [interquartile range, 0.23], 8.02 [interquartile range, 0.17], and 7.96 [interquartile range, 0.25], respectively; P < .001 and area under the receiver operating characteristic curve ≥0.80 in all comparisons). The area under the curve for the differentiation between groups 1 and 2 improved from 0.80 to 0.94 (sensitivity, 0.94; specificity, 0.84; positive predictive value, 0.76) when breath condensate pH values and Asthma Predictive Index scores were combined.

CONCLUSION

A reduced deaerated EBC pH value might help identify young asymptomatic children at high risk of asthma.

Isoprostanes-biomarkers of lipid peroxidation: their utility in evaluating oxidative stress and analysis

Isoprostanes (IsoPs) are key biomarkers for investigating the role of free radical generation in the pathogenesis of human disorders. To solve IsoPs-related problems with regard to isoprostanes, analytical tools are required. This paper reviews the problems and trends in this field focusing on the methodology for assaying biomarkers in exhaled breath condensate (EBC) samples. A large amount of work has been done in the qualitative and quantitative analysis of IsoPs, but a standardized method has yet to emerge. The methodologies described differ, either in the sample preparation steps or in the detection techniques, or both. Requiring a number of chromatographic steps, the relevant extraction and purification procedures are often critical and time-consuming, and they lead to a substantial loss of target compounds. Recent data show that EBC is a promising non-invasive tool for the evaluation of different diseases. Two main analytical approaches have been adopted for IsoPs measurement: immunological methods and mass spectrometry. The methodologies for the extraction, purification and analysis of IsoPs in EBC samples are presented.

Breath analysis of hydrogen peroxide as a diagnostic tool

The potential diagnostic significance of exhaled hydrogen peroxide (H(2)O(2)) in pulmonary and systemic disorders has received considerable interest over the last few decades. Despite large physiologic variability and low specificity, airway H(2)O(2) generation has been found to be consistently increased by inflammatory conditions. Furthermore, the level of exhaled H(2)O(2) has been associated with efficacy of treatment in various pulmonary diseases. To evaluate this potential biomarker, detection methods including standardization protocols have been developed. Despite these advances, more comprehensive and controlled studies are required. In this manuscript we review progress to date in the analytical measurement of exhaled H(2)O(2) and speculate on its potential clinical significance as a diagnostic tool.

Early diagnosis of asthma in young children by using non-invasive biomarkers of airway inflammation and early lung function measurements: study protocol of a case-control study

Background

Asthma is the most common chronic disease in childhood, characterized by chronic airway inflammation. There are problems with the diagnosis of asthma in young children since the majority of the children with recurrent asthma-like symptoms is symptom free at 6 years, and does not have asthma. With the conventional diagnostic tools it is not possible to differentiate between preschool children with transient symptoms and children with asthma. The analysis of biomarkers of airway inflammation in exhaled breath is a non-invasive and promising technique to diagnose asthma and monitor inflammation in young children. Moreover, relatively new lung function tests (airway resistance using the interrupter technique) have become available for young children. The primary objective of the ADEM study (Asthma DEtection and Monitoring study), is to develop a non-invasive instrument for an early asthma diagnosis in young children, using exhaled inflammatory markers and early lung function measurements. In addition, aetiological factors, including gene polymorphisms and gene expression profiles, in relation to the development of asthma are studied.

Methods/design

A prospective case-control study is started in 200 children with recurrent respiratory symptoms and 50 control subjects without respiratory symptoms. At 6 years, a definite diagnosis of asthma is made (primary outcome measure) on basis of lung function assessments and current respiratory symptoms ('golden standard'). From inclusion until the definite asthma diagnosis, repeated measurements of lung function tests and inflammatory markers in exhaled breath (condensate), blood and faeces are performed. The study is registered and ethically approved.

Discussion

This article describes the study protocol of the ADEM study. The new diagnostic techniques applied in this study could make an early diagnosis of asthma possible. An early and reliable asthma diagnosis at 2–3 years will have consequences for the management of the large group of young children with asthma-like symptoms. It will avoid both over-treatment of children with transient wheeze and under-treatment of children with asthma. This might have a beneficial influence on the prognosis of asthma in these young children. Besides, insight into the pathophysiology and aetiology of asthma will be obtained.

TRIAL REGISTRATION

This study is registered by clinicaltrials.gov (NCT00422747).