Does exposure to inflammatory particles modify the pattern of anion in exhaled breath condensate?

Exposure to environmental and occupational particulate matter (PM) induces health effects on the cardio-pulmonary system. In addition, associations between exposure to PM and metabolic syndromes like diabetes mellitus or obesity are now emerging in the literature. Collection of exhaled breath condensate (EBC) is an appealing non-invasive technique to sample pulmonary fluids. This hypothesis-generating study aims to (1) validate an ion chromatography method allowing the robust determination of different metabolism-related molecules (lactate, formate, acetate, propionate, butyrate, pyruvate, nitrite, nitrate) in EBC; (2) apply this method to EBC samples collected from workers exposed to quartz (a known inflammatory particle), to soapstone (a less inflammatory particle than quartz), as well as to controls. A multi-compound standard solution was used to determine the linearity range, detection limit, repeatability and bias from spiked EBC. The biological samples were injected without further treatment into an ion chromatograph with a conductivity detector. RTube^® were used for field collection of EBC from 11 controls, 55 workers exposed to soapstone and 12 volunteers exposed to quartz dust. The analytical method used proved to be adequate for quantifying eight anions in EBC samples. Its sub-micromolar detection limits and repeatability, combined with a very simple sample preparation, allowed an easy and fast quantification of different glycolysis or nitrosative stress metabolites. Using multivariate discriminant analysis to maximize differences between groups, we observed a different pattern of anions with a higher formate/acetate ratio in the EBC samples for quartz exposed workers compared to the two other groups. We hypothesize that a modification of the metabolic signature could be induced by exposure to inflammatory particles like quartz and might be observed in the EBC via a change in the formate/acetate ratio.

Method validation of nanoparticle tracking analysis to measure pulmonary nanoparticle content: the size distribution in exhaled breath condensate depends on occupational exposure

A particle exposure assessment based on the dose deposited in the lungs would be the gold standard for the evaluation of any resulting health effects. Measuring particles in exhaled breath condensate (EBC)-a matrix containing water and airway lining fluid-could help to evaluate particle retention in the lungs. This study aimed to (1) validate a nanoparticle tracking analysis (NTA) method for determining the particle number concentration and their hydrodynamic size distribution in EBC, and (2) apply this method to EBC collected from workers exposed to soapstone (n = 55) or quartz dust (n = 12) and controls (n = 11). A standard latex bead solution was used to determine the linear range, limit of detection (LOD), repeatability (coefficient of variation, CV), and bias in spiked EBC. An LM10 NanoSight instrument with NTA version 3.1 software was used for measurement. RTubes^® were used for field collection of EBC. The repeatability obtained for a D₅₀ size distribution in EBC showed less than 8% variability, with a bias <7%. The particle concentration was linear in the range ≤2.5 × 10⁸ particles ml^-1 with a LOD of 4 × 10⁶ particles ml^-1. A recovery of 117 ± 20% at 6.2 × 10⁷ particles ml^-1 was obtained with a CV <10% and a bias <20%. EBC from workers exposed to quartz, who experienced the largest exposure to silica particles, consistently exhibited a statistically significant (p < 0.01) higher concentration of particles in their EBC, with a size distribution shift towards larger values than the other groups. Results showed that the NTA technique performed well for characterizing the size distribution and concentrations of particles in EBC. The technique needs to be corroborated with a larger population of workers.

Home telemonitoring (forced expiratory volume in 1 s) in children with severe asthma does not reduce exacerbations

Some children with severe asthma develop frequent exacerbations despite intensive treatment. We sought to assess the outcome (severe exacerbations and healthcare use, lung function, quality of life and maintenance treatment) of a strategy based on daily home spirometry with teletransmission to an expert medical centre and whether it differs from that of a conventional strategy. 50 children with severe uncontrolled asthma were enrolled in a 12-month prospective study and were randomised into two groups: 1) treatment managed with daily home spirometry and medical feedback (HM) and 2) conventional treatment (CT). The children's mean age was 10.9 yrs (95% confidence interval 10.2-11.6). 44 children completed the study (21 in the HM group and 23 in the CT group). The median number of severe exacerbations per patient was 2.0 (interquartile range 1.0-4.0) in the HM group and 3.0 (1.0-4.0) in the CT group (p=0.38 with adjustment for age). There were no significant differences between the two groups for unscheduled visits (HM 5.0 (3.0-7.0), CT 3.0 (2.0-7.0); p=0.30), lung function (pre-β(2)-agonist forced expiratory volume in 1 s (FEV(1)) p=0.13), Paediatric Asthma Quality of Life Questionnaire scores (p=0.61) and median daily dose of inhaled corticosteroids (p=0.86). A treatment strategy based on daily FEV(1) monitoring with medical feedback did not reduce severe asthma exacerbations.

Cytokine concentrations in exhaled breath condensates in systemic sclerosis

BACKGROUND

Pulmonary fibrosis in systemic sclerosis (SSc) involves inflammatory processes in the lower respiratory tract. Analysis of exhaled breath condensate (EBC) is a non-invasive method for studying inflammatory mediators, such as cytokines, which are of interest from both physiological and therapeutic perspectives. The aim of this study was to assess and compare cytokine concentrations in the EBC of SSc patients and controls.

MATERIAL AND METHODS

EBC was collected from 19 SSc patients and 19 controls. We used a multiplex assay test kit to assay interleukin (IL)-2, -4, -6, -10, tumour necrosis factor-alpha, and interferon-gamma in samples concentrated by lyophilization.

RESULTS

Cytokine concentrations in EBC were higher in SSc patients than in controls. The stepwise analyses showed that IL-4 was the biomarker which contributed most to the discrimination between controls and patients (Wilk's Lambda = 0.55, p < 0.001). We observed significant negative correlations of EBC cytokines with total lung capacity and diffusion capacity of the lung for carbon monoxide.

CONCLUSIONS

These findings suggest that EBC sampling permits the non-invasive study of inflammation in SSc patients, and may be correlated with the severity of interstitial lung disease.

Short term response of circulating leptin to feeding and fasting in man: influence of circadian cycle

OBJECTIVE

To investigate whether acute feeding induces changes in circulating leptin levels in humans and whether these changes vary according to nycthemeral cycle.

METHODS

First experiment. Eighteen male subjects were given a fatty meal at 08.00 h. Blood sampling was performed for 10 h following this meal. Second experiment. Thirteen male subjects were given either a mixed meal or remained fasting either at night (starting at 01.00 h) or during the day (starting at 13.00 h). Blood samples were drawn every hour for a period of 8 h.

RESULTS

First experiment. Serum leptin levels increased progressively from a mean (s.d.) baseline of 3.8 +/- 2.2 ng/ml to a value of 4.5 +/- 2.7 ng/ml (P < 0.01) 8 h after the fatty meal. Second experiment. During the day, serum leptin levels increased progressively from 2.65 +/- 1.7 to 3.34 +/- 2.2 ng/ml (P < 0.001) 6 h after the test-meal and decreased from 2.68 +/- 1.5 to 1.9 +/- 1.1 ng/ml (P < 0.001) 8 h after the beginning of the fasting experiment. Similar results were obtained at night. No statistically significant differences in leptin levels were observed between day and night sessions in response to feeding (mean area under the curve: 3.0 +/- 4.1 vs 4.1 +/- 4.1 ng/ml) and fasting (-2.9 +/- 2.2 vs -1.5 +/- 2.2 ng/ml).

CONCLUSION

In two independent experiments, human serum leptin levels increase following food intake. This response is not influenced by nycthemeral cycle.

Assessment of biological chromium among stainless steel and mild steel welders in relation to welding processes

Air and biological monitoring were used for assessing external and internal chromium exposure among 116 stainless steel welders (SS welders) using manual metal arc (MMA), metal inert gas (MIG) and tungsten inert gas (TIG) welding processes (MMA: n = 57; MIG: n = 37; TIG: n = 22) and 30 mild steel welders (MS welders) using MMA and MIG welding processes (MMA: n = 14; MIG: n = 16). The levels of atmospheric total chromium were evaluated after personal air monitoring. The mean values for the different groups of SS welders were 201 micrograms/m3 (MMA) and 185 micrograms/m3 (MIG), 52 micrograms/m3 (TIG) and for MS welders 8.1 micrograms/m3 (MMA) and 7.3 micrograms/m3 (MIG). The curve of cumulative frequency distribution from biological monitoring among SS welders showed chromium geometric mean concentrations in whole blood of 3.6 micrograms/l (95th percentile = 19.9), in plasma of 3.3 micrograms/l (95th percentile = 21.0) and in urine samples of 6.2 micrograms/l (95th percentile = 58.0). Among MS welders, mean values in whole blood and plasma were rather more scattered (1.8 micrograms/l, 95th percentile = 9.3 and 1.3 micrograms/l, 95th percentile = 8.4, respectively) and in urine the value was 2.4 micrograms/l (95th percentile = 13.3). The analysis of variance of chromium concentrations in plasma previously showed a metal effect (F = 29.7, P < 0.001), a process effect (F = 22.2, P < 0.0001) but no metal-process interaction (F = 1.3, P = 0.25). Concerning urinary chromium concentration, the analysis of variance also showed a metal effect (F = 30, P < 0.0001), a process effect (F = 72, P < 0.0001) as well as a metal-process interaction (F = 13.2, P = 0.0004). Throughout the study we noted any significant differences between smokers and non-smokers among welders. Taking in account the relationships between chromium concentrations in whole, plasma or urine and the different welding process. MMA-SS is definitely different from other processes because the biological values are clearly higher. These higher levels are due to the very significant concentrations of total soluble chromium, mainly hexavalent chromium, in welding fumes.

Circadian variation of postprandial lipemia

The goal of the present study was to assess the influence of mealtime on postprandial lipemia. Thirteen healthy subject aged 19-32 y were given the same meal at night (0100) or during the day (1300) in random order: the meal contained 40% of estimated daily energy expenditure. Blood samples were drawn at baseline and hourly for 8 h after the meal. Serum total cholesterol, very-low-density-lipoprotein cholesterol (VLDL-C), low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol (HDL-C), triacylglycerols, VLDL-triacylglycerols, apolipoprotein (apo) A-I, and apo B were measured at each time point. In a subgroup of seven subjects a control fasting reference line was measured according to the same nocturnal and diurnal time schedule. The mean postprandial concentrations of triacylglycerol (P < 0.001), VLDL-triacylglycerol (P < 0.001), and VLDL-C (P < 0.001) were higher at night than during the day. In contrast, mean cholesterol (P < 0.01), LDL-C (P < 0.01), HDL-C (P < 0.001), apo A-I (P < 0.001), and apo B (P < 0.001) concentrations were lower after the night meal than after the day meal. The magnitude of the postprandial response was estimated by the area between the fasting and postprandial curves. The triacylglycerol and VLDL-triacylglycerol responses were not significantly different between night and day. The VLDL-C (P < 0.01) response was greater and LDL-C (P < 0.0001) and HDL-C (P < 0.01) responses were lower at night than during the day. These results indicate that circadian factors specifically affect serum cholesterol transport. Apo B (P < 0.01) and apo A-I (P < 0.01) responses followed LDL-C and HDL-C changes during the day but were dissociated from lipoprotein responses at night, suggesting that circadian apolipoprotein regulation is dissociated from that of serum lipids. The results of the present study indicate that postprandial lipid, lipoprotein, and apolipoprotein concentrations are affected by circadian factors.

Bronchial symptoms and respiratory function in workers exposed to methylmethacrylate

This study aimed to investigate the pulmonary effects of methylmethacrylate (MMA) in a group of occupationally exposed workers. In the exposed group 20% had chronic cough compared with 1% in controls. Spirometric values at the beginning of the workshift were similar in both groups, but a mild airways obstruction appeared during the workshift. The maximum expiratory flow when 50% of the forced vital capacity remained to be exhaled (MEF50) and the ratio of MEF50 to maximal expiratory flow (MEF50/MEF) decreased significantly during the workshift among exposed workers v controls (p = 0.04 and 0.01 respectively). Results remained unaffected after adjustment for smoking. Exposure to MMA seems to be responsible for a mild airways obstruction but further study on a larger population would be useful.