Nathalie Chérot-Kornobis

Analysis of nitrogen oxides (NOx) in the exhaled breath condensate (EBC) of subjects with asthma as a complement to exhaled nitric oxide (FeNO) measurements: a cross-sectional study

BackgroundThe study of pulmonary biomarkers with noninvasive methods, such as the analysis of exhaled breath condensate (EBC), provides a useful approach to the pathophysiology of asthma. Although many recent publications have applied such methods, numerous methodological pitfalls remain. The first stage of our study consisted of validating methods for the collection, storage and analysis of EBC; we next sought to clarify the utility of analysing nitrogen oxides (NOx) in the EBC of asthmatics, as a complement to measuring exhaled nitric oxide (FeNO).MethodsThis hospital-based cross-sectional study included 23 controls matched with 23 asthmatics. EBC and FeNO were performed and respiratory function measured. Intra-assay and intra-subject reproducibility were assessed for the analysis of NOx in the EBC of 10 healthy subjects.ResultsThe intraclass correlation coefficient (ICC) was excellent for intra-assay reproducibility and was moderate for intra-subject reproducibility (Fermanians classification). NOx was significantly higher in asthmatics (geometric mean [IQR] 14.4 μM [10.4 - 19.7] vs controls 9.9 μM [7.5 - 15.0]), as was FeNO (29.9 ppb [17.9 - 52.4] vs controls 9.6 ppb [8.4 - 14.2]). FeNO also increased significantly with asthma severity.ConclusionsWe validated the procedures for NOx analysis in EBC and confirmed the need for assays of other biomarkers to further our knowledge of the pathophysiologic processes of asthma and improve its treatment and control.

Non-invasive collection of exhaled breath condensate in rats: Evaluation of pH, H2O2 and NOx in lipopolysaccharide-induced acute lung injury

The analysis of exhaled breath condensate (EBC) offers the potential for identifying lung disease markers in humans and animals, but methodological issues and standardised procedures need to be addressed before the technique can be considered for use in applications to help understand the role of environmental pollution in respiratory diseases. The purpose of this study was to develop and implement a new device using a glass-chamber for collecting EBC non-invasively from rats in order to analyse EBC markers in lipopolysaccharide (LPS)-induced acute lung injury. Eighty-four adult rats were used in five different series of experiments to determine the source of EBC formation, intra-day and inter-day variability, and the influence of environmental parameters on EBC markers. The hypothesis that inflammation induces an oxidative stress was assessed by measuring pH, nitrogen oxides (NOx) and hydrogen peroxide (H(2)O(2)) in EBC. The results confirmed that EBC fluid was generated at the level of the respiratory tract. The repeatability studies of disease markers indicated higher concentrations of NOx and H(2)O(2) at midday compared to the morning, but there were no significant difference between measurements on consecutive days. EBC volume was influenced by both ambient temperature and humidity. Moreover, 3h after LPS challenge, significantly increased concentrations of both NOx and H(2)O(2) were observed in EBC of the LPS group compared with controls (P=0.005 and P=0.027, respectively). These results suggested that EBC collection may be a valuable tool to monitor the presence of markers, such as NOx and H(2)O(2), in an animal model of LPS-induced acute lung injury.

Both exhaled nitric oxide and blood eosinophil count were associated with mild allergic asthma only in non-smokers.

The fractional exhaled nitric oxide (FENO) and the blood eosinophil count (B‐eos) are markers of eosinophilic inflammation used in the diagnosis and management of asthma. The relationships between smoking cigarette and both FENO and B‐eos are complex and raise questions about the association between these markers and asthma in smokers.

Global Lung Function Initiative reference equations better describe a middle-aged, healthy French population than the European Community for Steel and Coal values

Spirometry plays a pivotal role in the clinical evaluation and management of respiratory diseases. Pulmonary function varies with age, height, sex and ethnicity, and test results need to be compared with predicted values and lower limits of normal (LLN) and upper limits of normal (ULN), that are appropriate for the individual being tested [1]. The European Community for Steel and Coal (ECSC) first published reference spirometric values for healthy non-smokers in 1983 based on a collation of regression equations [2]. In 2012, the Global Lung Function Initiative (GLI) presented prediction equations derived from measured values of a large population [1]. These newer statistical procedures provided us for the first time with a single equation for ages from 3 years through to 95 years. Measured values are converted to z-scores which describe how many standard deviations a measured value differs from the predicted value and these are independent of sex, age and height. GLI reference equations better describe a middle-aged, healthy French population than the ECSC values http://ow.ly/xF773022Xhy

Manganese in exhaled breath condensate: A new marker of exposure to welding fumes

OBJECTIVE To evaluate manganese in exhaled breath condensate (Mn-EBC) as an indicator of exposure to fumes from metal inert gas welding process. METHODS We collected EBC and urine from 17 welders and 16 unexposed control subjects after 5 days exposure. Concentrations of manganese (Mn), nickel (Ni), iron (Fe) and chromium (Cr) were measured in EBC and urine samples and correlated with cumulative exposure indices for the working week (CIW) and for the total welding years (WY), based on duration of welding activity and atmospheric metal measurements. RESULTS Concentrations of Mn and Ni in EBC were significantly higher among welders than controls whereas this difference was not significant for Mn in urine. Levels of Mn and Ni in EBC were not correlated with their respective levels in urine. The linear regressions found significant positive coefficients between Mn-EBC, Ni-EBC, Ni-U and Cr-U concentrations and the cumulative exposure indices. Taking into account tobacco use, statistical analysis showed the same trends except for the relationship between Mn-U and CIW. CONCLUSION This pilot study showed that Mn-EBC, as well as Ni-EBC, can serve as reliable indices of occupational exposure to welding fumes and provide complimentary toxicokinetic information to that provided by urine analyses.

Mica Dust and Pneumoconiosis Example of a Pure Occupational Exposure in a Muscovite Milling Unit

Objective: We present pulmonary disorders of four employees who were exposed to high concentration of pure mica dust in a muscovite milling unit. Method: All cases underwent traditional examinations with a dual-energy chest computed tomographic scan. An analysis of exhaled breath condensate by Raman microspectrometry and of mineralogical content of a lung biopsy was performed for one case. Results: All cases showed bilateral micronodular ground glass opacities and mediastinal and hilar hyperdense lymph nodes consistent with the nodal sequestration of mineral particles. Histological analysis showed giant cell granulomas without typical silicotic nodule with high concentration of birefringent particles consistent with mica. Mica particles found in the exhaled breath condensate were identical to particles in ambient air at the company. Conclusion: Occupational exposure to mica dust is responsible for diffuse infiltrative lung disease by overload processes.

Exhaled breath NOx levels in a middle-aged adults population-based study: reference values and association with the smoking status

BACKGROUND Biomarkers in exhaled breath condensate (EBC) are potentially sensitive indicators of early biochemical changes in airways following exposure to pneumotoxic substances, particularly in susceptible subjects. NOx are the stable end products of the nitrite-nitrate-NO oxidative stress pathway and can be used to monitor airway inflammatory diseases, especially in asthma. Nevertheless, population-based surveys are needed to better interpret EBC NOx levels in clinical studies. The aim of this study was to establish reference values of EBC NOx in a large group of middle-aged, healthy adults of a sample of the general population with particular focus on the smoking status. METHODS The EBC NOx levels were analysed from 2872 subjects among the ELISABET population-based cross sectional study including a representative sample of men and women aged from 40 to 66 years olds conducted in northern France, which included comprehensive questionnaires by interview and spirometry data. Healthy participants were defined as participants with no self-reported respiratory disease. RESULTS For the healthy subjects (n = 1251), the median NOx concentration (IQR) was equal to 7.2  μM (3.12) and concentrations of NOx in EBC did not differ significantly according to smoking status. The upper fifth percentile (95%) (ULN) of NOx concentrations among healthy subjects was equal to 13.6  μM, ranging from 12.7  μM (smokers) to 14.4  μM (ex smokers). Among subjects with EBC NOx values higher than the ULN and compared with subjects that had EBC NOx values lower than the ULN, we found a significant higher proportion of subjects with current asthma (10.5% vs 6.5%) or with chronic bronchitis symptoms (7.6% vs 3.3%). CONCLUSION This population-based study has provided the distribution and the upper limit reference value of a nitrosative stress biomarker (NOx) in EBC of middle aged, healthy adults. EBC NOx levels were not associated with smoking status.

Increased Levels of 8-Isoprostane in EBC of NO2-Exposed Rats

Several epidemiological studies have shown the impact on respiratory health of pollution of nitrogen dioxide (NO2), particulate matter (PM10), and ozone (O3) as an environmental mixture. However, the influence of individual components of airborne pollutants is less well known. Our study examined the cumulative effects of a single pollutant, NO2, on sensitized rats by measurement of isoprostane release in exhaled breath condensate (EBC). Three groups of six rats were used: (1) controls (only exposed to air), (2) sensitized and challenged by ovalbumin and exposed to air, and (3) sensitized, challenged by ovalbumin, and exposed to NO2. There was no marked change in 8-isoprostane levels in EBC of sensitized rats, whereas a significant increase of 8-isoprostane was found in rats sensitized and exposed to NO2. Data indicate effect of exposure to NO2 is evident as increased 8-isoprostane levels in EBC, a relevant marker for assessment of pulmonary inflammation or oxidant stress and conventionally found in EBC of asthmatic subjects.

Short-term exposure to air pollution: Associations with lung function and inflammatory markers in non-smoking, healthy adults

INTRODUCTION Air pollution impacts health by increasing mortality and the incidence of acute events in unhealthy individuals. In contrast, the acute effects of pollution in healthy individuals are less obvious. The present study was designed to evaluate the associations between short-term exposure to air pollution on one hand and lung function, and inflammatory markers on the other in middle-aged, non-smoking adults with no respiratory disease, in two urban areas in northern France. METHODS A sample of 1506 non-smoking adults (aged from 40 to 65) with no respiratory disease was selected from the participants in the 2011-2013 cross-sectional Enquête Littoral Souffle Air Biologie Environnement (ELISABET) survey in two urban areas in the northern France. We evaluated the associations between (i) mean levels of particulate matter with aerodynamic diameter < 10 μm (PM10), nitrogen dioxide (NO2) and ozone (O3) exposure on the day and the day before the study examination for each participant, and (ii) spirometry data and levels of inflammatory markers. Coefficients of multiple linear regression models were expressed (except for the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio) as the percentage change [95% confidence interval] per 10 μg increment in each pollutant. RESULTS Levels of PM10, NO2 and O3 exposure were below or only close to the World Health Organizations recommended limits in our two study areas. An increment in NO2 levels was significantly associated with a lower FEV1/FVC ratio (-0.38 [-0.64; -0.12]), a lower forced expiratory flow between 25% and 75% of FVC (FEF25-75%) (-1.70 [-3.15; -0.23]), and a lower forced expiratory flow measured at 75% of FVC (FEF75%) (-3.07 [-4.92; -1.18]). An increment in PM10 levels was associated with lower FEF75% (-1.41 [-2.79; -0.01]) and a non-significant elevation in serum levels of high-sensitivity C-reactive protein (+3.48 [-0.25; 7.36], p = 0.07). Lastly, an increment in O3 levels was associated with a significantly higher blood eosinophil count (+2.41 [0.10; 4.77]) and a non-significant elevation in fractional exhaled nitric oxide (+2.93 [-0.16; 6.13], p = 0.06). CONCLUSION A short-term exposure to air pollution was associated with a subclinical decrement in distal lung function and increment in inflammatory markers in healthy inhabitants of two urban areas in France. If these exploratory results are confirmed, this could suggest that even moderate levels of air pollution could have an impact on respiratory health on the general population, and not solely on susceptible individuals.