Exhaled Breath Condensate Leukotriene B4 Research Articles

Evaluation of Interleukin-6, Leukotriene B-4, and Nitric Oxide Levels in Exhaled Breath Condensate of Asymptomatic Obese Individuals: Are Obese Patients Under Risk of Developing Asthma?

If systemic inflammation in relation with obesity causes asthma, the detection of increased airway inflammation among obese individuals who do not have any respiratory symptoms can be also beneficial in indentifying obese patients who are at risk of developing asthma. The aim of this study was to evaluate the systemic and airway inflammation of asymptomatic obese and non-obese individuals. Obese and non-obese individuals with no respiratory symptoms were included. Inflammatory biomarkers such as C-reactive protein (CRP), exhaled breath condensate (EBC) interleukin-6 (IL-6), EBC leukotriene B-4 (LTB-4), and EBC nitric oxide (NO) levels of obese and non-obese individuals were determined. Forty-five obese individuals (body mass index [BMI]≥30) and 31 non-obese individuals (BMI≤25) as a control group were included in this study. The mean age of the obese group (38.7±11.4 years) was significantly higher than the one of the non-obese group (29.5±8.6 years; p<0.001). There was no significant relationship between gender and BMI (χ2 =1.471, p=0.225). CRP levels were significantly higher in the obese group (6.94±8.28) than the non-obese group (3.29±0.39; p<0.001). The levels of EBC IL-6 in obese and non-obese group were found as 22.61±12.53 and 21.08±14.39, respectively (p=0.624). There was no significant difference between EBC NO levels of the obese group and non-obese group (24.35±10.9 vs. 21.56±7.83; p=0.226). No significant difference was found between the EBC LTB-4 level in the obese group and the non-obese group (36.39±89.82 vs. 16.64±17.45; p=0.231). Increased systemic inflammation in obese individuals who had no respiratory symptoms might indicate the tendency of asthma. However, airway inflammation was not significantly different between groups. Therefore the relationship between obesity and asthma should be investigated in future large-scale studies determining the direct effects of adipokines on airways.

Exhaled breath condensate hydrogen peroxide, pH and leukotriene B4 are associated with lower airway inflammation and airway cytology in the horse.

Exhaled breath condensate (EBC) analysis is a noninvasive method to assess the lower respiratory tract. In human subjects, EBC hydrogen peroxide (H2 O2 ), pH and leukotriene B4 (LTB4 ) are useful for detection and monitoring of inflammatory lung diseases, including asthma. To determine associations between EBC biomarkers and cytological and endoscopic definitions of lower airway inflammation (LAI) while controlling for sampling and environmental variables. Prospective, cross-sectional study. Clinical, endoscopic and airway cytological findings from 47 horses were compared with EBC pH and concentrations of H2 O2 and LTB4 by univariate and multivariable analyses. Dichotomous (presence/absence of airway inflammation) and continuous outcome variables (differential cell counts in tracheal aspirate and bronchoalveolar lavage fluid, BALF) were evaluated and potential effects of collection and methodological factors were included. EBC pH and H2 O2 concentrations were higher in horses with LAI and both were positively associated with the percentage of neutrophils in BALF (P<0.05). Mast cell percentage in BALF was negatively associated with EBC pH, and BALF eosinophil percentage was positively associated with EBC LTB4 (P<0.05). Ambient temperature, relative humidity and assay methodology significantly impacted some analytes. LAI is challenging to categorise due to a variety of clinical and cytological phenotypes. Although the study was designed to overcome this limitation, numbers of horses were small in some categories. EBC pH and H2 O2 concentrations are altered by airway inflammation, suggesting a role for these biomarkers in the diagnosis and monitoring of airway disease. Environmental and methodological factors can influence these biomarkers and should be considered in the interpretation of results.

Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates

PurposeWelders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders’ airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day.MethodIn an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m3) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure.ResultsNo adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms.ConclusionDespite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).

Exhaled leukotriene B4 in children with community acquired pneumonia

The infiltrate in pneumonia is characterized by a large number of activated neutrophils, for which leukotriene B4 (LTB4) is a strong chemotactic agent. Exhaled breath condensate (EBC) is a non-invasive technique for studying the lower airways. The present study was conducted to measure EBC LTB4 as a potential non-invasive marker of inflammatory response in community acquired pneumonia (CAP). Eighteen children with CAP and 17 healthy children were recruited (age 5-13). The CAP children underwent physical examination, chest X-ray, leukocyte count and C-reactive protein measurement. The CAP and the control children performed spirometry, exhaled nitric oxide measurement (FE(NO)) and EBC collection for LTB4 assessment. In the CAP children spirometry, FE(NO) and EBC collection were repeated twice over a 1-month follow-up. LTB4 EBC concentrations were higher in children with CAP than in healthy controls (10 pg/ml [7.0-15.3] vs. 3 pg/ml [3.0-6.9], P = 0.001) and decreased after 1 week (3 pg/ml [3.0-7.2], P < 0.01) with no further change a month later. In the acute phase spirometry demonstrated a restrictive pattern that gradually improved later. No difference in FE(NO) levels was found between children with CAP and healthy controls. Exhaled LTB4 levels increase in CAP and return to normal after 1 week. EBC collection is feasible in children with CAP and may represent a new way to non-invasively monitor the lung's biological response to infections.

Non-invasive biomarkers and pulmonary function in smokers

Limited information exists regarding measurement, reproducibility and interrelationships of non-invasive biomarkers in smokers. We compared exhaled breath condensate (EBC) leukotriene B4 (LTB4) and 8-isoprostane, exhaled nitric oxide, induced sputum, spirometry, plethysmography, impulse oscillometry and methacholine reactivity in 18 smokers and 10 non-smokers. We assessed the relationships between these measurements and within-subject reproducibility of EBC biomarkers in smokers. Compared to non-smokers, smokers had significantly lower MMEF % predicted (mean 64.1 vs 77.7, p = 0.003), FEV1/FVC (mean 76.2 vs 79.8 p = 0.05), specific conductance (geometric mean 1.2 vs 1.6, p = 0.02), higher resonant frequency (mean 15.5 vs 9.9, p = 0.01) and higher EBC 8-isoprostane (geometric mean 49.9 vs 8.9 pg/ml p = 0.001). Median EBC pH values were similar, but a subgroup of smokers had airway acidification (pH < 7.2) not observed in non-smokers. Smokers had predominant sputum neutrophilia (mean 68.5%). Repeated EBC measurements showed no significant differences between group means, but Bland Altman analysis showed large individual variability. EBC 8-isoprostane correlated with EBC LTB4 (r = 0.78, p = 0.0001). Sputum supernatant IL-8 correlated with total neutrophil count per gram of sputum (r = 0.52, p = 0.04) and with EBC pH (r = -0.59, p = 0.02). In conclusion, smokers had evidence of small airway dysfunction, increased airway resistance, reduced lung compliance, airway neutrophilia and oxidative stress.

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

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

Reproducibility of exhaled biomarkers in COPD?the road less traveled

In recent years, interest in the measurement of exhaled biomarkers has increased, mainly driven by the unmet clinical need to monitor airway inflammation and the response to antiinflammatory therapy. Beside exhaled nitric oxide measurement that entered clinical practice, measurement of biomarkers in exhaled breath condensate (EBC) is a rapidly expanding area of this field. EBC is easy to collect as it only requires the noninvasive collection of exhaled breath in a cold trap. The obtained fluid is a complex diluted solution of diverse biomarkers with various chemical stabilities. Due to the complexity of EBC and the fact that it is a much diluted sample, there are still several unsolved issues about standard protocols for measurements and there is a lack of reproducibility data for different biomarkers, particularly in disease states. The lack of knowledge and evidence on certain areas limited the ability of the European Respiratory Society/American Thoracic Society Task Force to make firm guidelines for each aspect of this sampling technique and prompted the authors to highlight areas for further research (Horvath et al 2005). The current issue of the International Journal of COPD contains an important methodological contribution to this rapidly growing field (Borrill et al 2007). The authors performed a carefully designed study to assess within assay, within and between day reproducibility of EBC leukotriene B4 (LTB4) and 8-isoprostane concentration measured by enzyme immunoassays (ELISA). They demonstrated that within assay variability was small, but there was a considerable within and between day variability for these biomarkers. Their two main conclusions derived from the study are: 1) the cause of relatively low reproducibility of EBC LTB4 and 8-isoprostane is multi-factorial including both biological and methodological variability; 2) the high level of variability they observed casts doubt on the current EBC methodology used to assess LTB4 and 8-isoprostane. The very important contribution of this article to the field is the careful analysis of reproducibility for two biomarkers. It has been shown for some EBC biomarkers that oral contamination during sampling (Gaber et al 2006; Marteus et al 2005), differences in collecting surfaces (Rosias et al 2006), different assay techniques (Huszar et al 2005), and mode of standardization (Kullmann et al 2007) all can contribute to limited reproducibility of results. It is extremely difficult to address all potential methodological biases of ELISA when assessing EBC. Intra-assay variability is relatively easy to assess: one can compare readings of duplicate or triplicate aliquots of the same samples. Determination of inter-assay differences again is best done from the same samples adding aliquots of it to two different plates of the assay. If results of inter-assay reproducibility are good, then different batches of the assay can be used to determine intra-day or intra-week reproducibility. This potential difference needs to be taken into account when using EBC as a source of airway biomarkers (Huszar et al 2005). Determination of intra-week reproducibility then can be performed by 1) keeping the first sample for a week and measuring it together with the second (in this case however the potential effect of storing on mediator concentration needs to be taken into account); or 2) measuring the two samples by different batches of ELISA from the same manufacturer (in this case inter-assay variability complicates interpretation). Although it cannot be established from the study by Borrill and colleagues (2007) what kind of arrangement they used for the determination of intra-day and intra-week variability, their conclusion about the complexity of reproducibility holds very well. Another issue their study touches upon is the limitations of the usefulness of biomarkers with limited reproducibility. Precise standardizations of traditional lung function tests and exhaled nitric oxide measurements were essential for these variables to provide accurate, well reproducible readings and gain clinical acceptance. EBC biomarkers have to travel through the same path before they can become clinically meaningful tools. The study by Borrill and colleagues (2007) adds important insight into the interpretation of observed differences of EBC LTB4 and 8-isoprostane and it also emphasizes the need for reproducibility data, not only in healthy subjects, but also in patients. COPD is a disease with fluctuation of airway inflammation and oxidative stress that only partially reflected by clinical symptoms therefore it is reasonable to assume a lower than normal degree of reproducibility of biomarkers representing pathophysiological events of the disease even under stable conditions. Therefore, long-term follow-up studies assessing biomarker reproducibility can help to better understand the dynamics of EBC biomarker profile in this multiplex disease. I hope you will find the article by Borrill and colleagues (2007) stimulating from both clinical and research point of views.