Effects of short-term exposures to ultrafine particles near an airport in healthy subjects.

BACKGROUND: Recent studies reported elevated concentrations of ultrafine particles (UFP) near airports. Little is known about the health effects of UFP from aviation. Since UFP can deposit deep into the lungs and other organs, they may cause significant adverse health effects. OBJECTIVE: We investigated health effects of controlled short-term human exposure to UFP near a major airport. METHODS: In this study, 21 healthy non-smoking volunteers (age range: 18-35 years) were repeatedly (2-5 visits) exposed for 5 h to ambient air near Schiphol Airport, while performing intermittent moderate exercise (i.e. cycling). Pre- to post-exposure changes in cardiopulmonary outcomes (spirometry, forced exhaled nitric oxide, electrocardiography and blood pressure) were assessed and related to total- and size-specific particle number concentrations (PNC), using linear mixed effect models. RESULTS: The PNC was on average 53,500 particles/cm3 (range 10,500-173,200). A 5-95th percentile increase in exposure to UFP (i.e. 125,400 particles/cm3) was associated with a decrease in FVC of -73.8 mL (95% CI -138.8 - -0.4) and a prolongation of the corrected QT (QTc) interval by 9.9 ms (95% CI 2.0 - 19.1). These effects were associated with particles < 20 nm (mainly UFP from aviation), but not with particles > 50 nm (mainly UFP from road traffic). DISCUSSION: Short-term exposures to aviation-related UFP near a major airport, was associated with decreased lung function (mainly FVC) and a prolonged QTc interval in healthy volunteers. The effects were relatively small, however, they appeared after single exposures of 5 h in young healthy adults. As this study cannot make any inferences about long-term health impacts, appropriate studies investigating potential health effects of long-term exposure to airport-related UFP, are urgently needed.

Detection of Staphylococcus aureus in cystic fibrosis patients using breath VOC profiles.

Staphylococcus aureus (S. aureus) is a common bacterium infecting children with cystic fibrosis (CF). Since current detection methods are difficult to perform in children, there is need for an alternative. This proof of concept study investigates whether breath profiles can discriminate between S. aureus infected and non-infected CF patients based on volatile organic compounds (VOCs). We collected exhaled breath of CF patients with and without S. aureus airways infections in which VOCs were identified using gas chromatography-mass spectrometry. We classified these VOC profiles with sparse partial least squares discriminant analysis. Multivariate breath VOC profiles discriminated infected from non-infected CF patients with high sensitivity (100%) and specificity (80%). We identified the nine compounds most important for this discrimination. We successfully detected S. aureus infection in CF patients, using breath VOC profiles. Nine highlighted compounds can be used as a focus point in further biomarker identification research. The results show considerable potential for non-invasive diagnosis of airway infections.

Identification of Pseudomonas aeruginosa and Aspergillus fumigatus mono- and co-cultures based on volatile biomarker combinations.

Volatile organic compound (VOC) analysis in exhaled breath is proposed as a non-invasive method to detect respiratory infections in cystic fibrosis patients. Since polymicrobial infections are common, we assessed whether we could distinguish Pseudomonas aeruginosa and Aspergillus fumigatus mono- and co-cultures using the VOC emissions. We took headspace samples of P. aeruginosa, A. fumigatus and co-cultures at 16, 24 and 48 h after inoculation, in which VOCs were identified by thermal desorption combined with gas chromatography - mass spectrometry. Using multivariate analysis by Partial Least Squares Discriminant Analysis we found distinct VOC biomarker combinations for mono- and co-cultures at each sampling time point, showing that there is an interaction between the two pathogens, with P. aeruginosa dominating the co-culture at 48 h. Furthermore, time-independent VOC biomarker combinations were also obtained to predict correct identification of P. aeruginosa and A. fumigatus in mono-culture and in co-culture. This study shows that the VOC combinations in P. aeruginosa and A. fumigatus co-microbial environment are different from those released by these pathogens in mono-culture. Using advanced data analysis techniques such as PLS-DA, time-independent pathogen specific biomarker combinations can be generated that may help to detect mixed respiratory infections in exhaled breath of cystic fibrosis patients.

Extended nitric oxide analysis may improve personalized anti-inflammatory treatment in asthmatic children with intermediate F(E)NO50.

Exhaled nitric oxide (F(E)NO) is elevated in asthma, and a clinical practice guideline has been published with recommendations for anti-inflammatory treatment. It summarizes that a F(E)NO at an expiratory flow rate of 50 ml s(-1) (F(E)NO50) above 35 ppb in children indicates eosinophilic inflammation, and the most likely response is to use inhaled corticosteroids. Intermediate F(E)NO50 between 20-35 ppb should be interpreted cautiously. The aim of the study was to investigate this guideline in a small group of asthmatic children. Thirty-seven asthmatic children; 23 boys and 14 girls, visited the outpatient clinic, and provided exhaled breath samples for offline NO measurement. These samples were analysed with chemiluminescence techniques. Three flow rates, namely 16, 90 and 230 ml s(-1) were used for the extended NO analysis (Högman-Meriläinen algorithm, HMA) to estimate the alveolar concentration (C(A)NO), diffusion rate of the airway wall (D(aw)NO) and airway wall content (C(aw)NO). For accuracy of the HMA, the estimated value of F(E)NO at 50 ml s(-1) (F(E)NO50) was compared with measured F(E)NO50. In nine children the difference was more than 5 ppb and the data were therefore excluded. Five children with F(E)NO50 <20 ppb had no known allergy and their F(E)NO50 geometrical mean (25th; 75th percentile) was 11 (10;14) and CawNO was 32 (20;43) ppb. Ten children with F(E)NO50 > 35 ppb had an allergy and had F(E)NO50 of 56 (47;60) ppb and C(aw)NO of 140 (121;172) ppb. Thirteen children with allergies, with intermediate F(E)NO50, had F(E)NO50 of 27 (25;30) ppb with a wide range of C(aw)NO. In five of these children, values were comparable to healthy children, 44 (43;50) ppb while eight children had elevated C(aw)NO values of 108 (95;129) ppb. Our data indicate the clinical potential use of extended NO analysis to determine the personal target value of F(E)NO50 for monitoring the treatment outcome. Furthermore, for children with intermediate F(E)NO50 more than half of them could possibly benefit from an adjustment of inhaled corticosteroids if the C(aw)NO value was considered.