Flunisolide decreases exhaled nitric oxide and nitrotyrosine levels in asthmatic 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."

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.

Effect of montelukast monotherapy on oxidative stress parameters and DNA damage in children with asthma

BACKGROUND

There is ample knowledge reported in the literature about the role of oxidative stress in asthma pathogenesis. It is also known that the interaction of reactive oxygen species with DNA may result in DNA strand breaks. The aim of this study was to investigate if montelukast monotherapy affects oxidative stress and DNA damage parameters in a population of pediatric asthma patients.

METHODS

Group I consisted of 31 newly diagnosed asthmatic patients not taking any medication, and group II consisted of 32 patients who had been treated with montelukast for at least 6 months. Forty healthy control subjects were also enrolled in the study. Plasma total oxidant status (TOS) and total antioxidant status (TAS) were measured to assess oxidative stress. DNA damage was assessed by means of alkaline comet assay.

RESULTS

The patients in both group I and group II had statistically significant higher plasma TOS (13.1 ± 4 and 11.1 ± 4.1 μmol H2O2 equivalent/liter, respectively) and low TAS levels (1.4 ± 0.5 and 1.5 ± 0.5 mmol Trolox equivalent/liter, respectively) compared with the control group (TOS: 6.3 ± 3.5 μmol H2O2 equivalent/liter and TAS: 2.7 ± 0.6 mmol Trolox equivalent/liter; p < 0.05). DNA damage was 18.2 ± 1.0 arbitrary units (a.u.) in group I, 16.7 ± 8.2 a.u. in group II and 13.7 ± 3.4 a.u. in the control group. There were statistically significant differences only between group I and the control group (p < 0.05).

CONCLUSIONS

According to the findings, montelukast therapy makes only minimal but not statistically significant improvement in all TOS, TAS and DNA damage parameters.

Effect of nebulized beclomethasone on airway inflammation and clinical status of children with allergic asthma and rhinitis: a randomized, double-blind, placebo-controlled study

We aimed to evaluate the therapeutic effect of nebulized beclomethasone dipropionate (nBDP) on both allergic asthma and rhinitis. In a randomized, double-blind, placebo-controlled study, 40 children (mean age 10.7 ± 2.1 years) with allergic asthma and rhinitis received either nBDP (daily dose of 800 µg, administered twice daily) or placebo for 4 weeks (with a face mask), after a 2-week run-in period of clinical assessment. Nasal and oral fractional exhaled nitric oxide (FeNO) measurements together with pulmonary function tests, nasal and oral exhaled breath condensate (EBC) collection for pH and interleukin-5 (IL-5) measurements as well as nasal and bronchial symptom scores were obtained at baseline and after 4-week treatment. A significant improvement in oral FeNO, oral and nasal EBC IL-5 and nasal EBC pH was observed in the nBDP group when comparing the values with baseline, together with an improvement in symptom score of the visual analogue scale, nasal obstruction, sneezing, rhinorrhea, breathing difficulty, cough, wheezing and sleep disturbance (nBDP end treatment vs. baseline, Wilcoxon signed-rank test). nBDP was more effective than placebo (ANCOVA test) in improving [difference Δ = response after treatment at the last visit (active or placebo) - value at baseline] nasal pH, oral IL-5, oral FeNO, forced expiratory volume in 1 s, forced expiratory volume in 1 s/forced vital capacity, peek expiratory flow, visual analogue scale, breathing difficulty, cough, wheezing and sleep disturbance scores. No differences were observed between the nBDP and the placebo group for symptom score of rhinitis. nBDP is a useful treatment for airway inflammation and clinical status in children with concomitant allergic asthma and rhinitis.

Exhaled breath condensates in asthma: diagnostic and therapeutic implications

Exhaled breath condensate (EBC) collection and analysis offers a unique non-invasive method to sample the airway lining fluid. It enables classification and quantification of airway inflammation associated with various pulmonary diseases such as asthma. Over the last decade, innumerable efforts have been made to identify biomarkers in EBC for diagnosis and management of asthma. The aim of this review is to consolidate information available to date, summarize findings from studies and identify potential biomarkers which need further refinement through translational research prior to application in clinical practice.

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.

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.

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.

Airway biomarkers of the oxidant burden in asthma and chronic obstructive pulmonary disease: current and future perspectives

The pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) has been claimed to be attributable to increased systemic and local oxidative stress. Detection of the oxidant burden and evaluation of their progression and phenotypes by oxidant biomarkers have proved challenging and difficult. A large number of asthmatics are cigarette smokers and smoke itself contains oxidants complicating further the use of oxidant biomarkers. One of the most widely used oxidant markers in asthma is exhaled nitric oxide (NO), which plays an important role in the pathogenesis of asthma and disease monitoring. Another oxidant marker that has been widely investigated in COPD is 8-isoprostane, but it is probably not capable of differentiating asthma from COPD, or even sensitive in the early assessment of these diseases. None of the current biomarkers have been shown to be better than exhaled NO in asthma. There is a need to identify new biomarkers for obstructive airway diseases, especially their differential diagnosis. A comprehensive evaluation of oxidant markers and their combinations will be presented in this review. In brief, it seems that additional analyses utilizing powerful tools such as genomics, metabolomics, lipidomics, and proteomics will be required to improve the specificity and sensitivity of the next generation of biomarkers.