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Antwerpen, Belgium

Pieters N.,Hasselt University | Koppen G.,Flemish Institute for Technological Research | Smeets K.,Hasselt University | Napierska D.,Catholic University of Leuven | And 12 more authors.
PLoS ONE | Year: 2013

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are formed in combustion processes. At the cellular level, exposure to PAHs causes oxidative stress and/or some of it congeners bind to DNA, which may interact with mitochondrial function. However, the influence of these pollutants on mitochondrial DNA (mtDNA) content remains largely unknown. We determined whether indoor exposure to PAHs is associated with mitochondrial damage as represented by blood mtDNA content. Blood mtDNA content (ratio mitochondrial/nuclear DNA copy number) was determined by real-time qPCR in 46 persons, both in winter and summer. Indoor PAH exposure was estimated by measuring PAHs in sedimented house dust, including 6 volatile PAHs and 8 non-volatile PAHs. Biomarkers of oxidative stress at the level of DNA and lipid peroxidation were measured. In addition to the epidemiologic enquiry, we exposed human TK6 cells during 24 h at various concentrations (range: 0 to 500 μM) of benzo(a)pyrene and determined mtDNA content. Mean blood mtDNA content averaged (±SD) 0.95±0.185. The median PAH content amounted 554.1 ng/g dust (25th-75th percentile: 390.7-767.3) and 1385 ng/g dust (25th-75th percentile: 1000-1980) in winter for volatile and non-volatile PAHs respectively. Independent for gender, age, BMI and the consumption of grilled meat or fish, blood mtDNA content decreased by 9.85% (95% CI: -15.16 to -4.2; p = 0.002) for each doubling of non-volatile PAH content in the house dust in winter. The corresponding estimate for volatile PAHs was -7.3% (95% CI: -13.71 to -0.42; p = 0.04). Measurements of oxidative stress were not correlated with PAH exposure. During summer months no association was found between mtDNA content and PAH concentration. The ability of benzo(a)pyrene (range 0 μM to 500 μM) to lower mtDNA content was confirmed in vitro in human TK6 cells. Based on these findings, mtDNA content can be a target of PAH toxicity in humans. © 2013 Pieters et al. Source


Koppen G.,Flemish Institute for Technological Research | Bloemen K.,Flemish Institute for Technological Research | Colles A.,Flemish Institute for Technological Research | Nelen V.,Provincial Institute of Hygiene | And 3 more authors.
Critical Reviews in Environmental Science and Technology | Year: 2011

The role of air pollution exposure on the development of asthma remains unclear. This can only be answered by prospective cohort studies. The authors give an overview of cohort studies focusing mainly on the role of early exposure, investigating the association between outdoor exposure early in life and respiratory or allergy symptoms in the growing children. Based on those studies, there is a suggestive evidence for a causal association between childhood asthma symptoms and exposure to traffic-related air pollutants. © 2011 Taylor & Francis Group, LLC. Source


De Coster S.,Ghent University | De Coster S.,Vrije Universiteit Brussel | van Leeuwen D.M.,Maastricht University | Jennen D.G.J.,Maastricht University | And 9 more authors.
Environmental and Molecular Mutagenesis | Year: 2013

Flanders, Belgium, is one of the most densely populated areas in Europe. The Flemish Environment and Health Survey (2002-2006) aimed at determining exposure to pollutants of neonates, adolescents, and older adults and to assess associated biological and health effects. This study investigated genome wide gene expression changes associated with a range of environmental pollutants, including cadmium, lead, PCBs, dioxin, hexachlorobenzene, p,p'-DDE, benzene, and PAHs. Gene expression levels were measured in peripheral blood cells of 20 adults with relatively high and 20 adults with relatively low combined internal exposure levels, all non-smokers aged 50-65. Pearson correlation was used to analyze associations between pollutants and gene expression levels, separately for both genders. Pollutant- and gender-specific correlation analysis results were obtained. For organochlorine pollutants, analysis within genders revealed that genes were predominantly regulated in opposite directions in males and females. Significantly modulated pathways were found to be associated with each of the exposure biomarkers measured. Pathways and/or genes related to estrogen and STAT5 signaling were correlated to organochlorine exposures in both genders. Our work demonstrates that gene expression in peripheral blood is influenced by environmental pollutants. In particular, gender-specific changes are associated with organochlorine pollutants, including gender-specific modulation of endocrine related pathways and genes. These pathways and genes have previously been linked to endocrine disruption related disorders, which in turn have been associated with organochlorine exposure. Based on our results, we recommend that males and females be considered separately when analyzing gene expression changes associated with exposures that may include chemicals with endocrine disrupting properties. Environ. Mol. Mutagen. 54:574-588, 2013. © 2013 Wiley Periodicals, Inc. Source


Dhooge W.,Ghent University | Den Hond E.,Flemish Institute for Technological Research | Koppen G.,Flemish Institute for Technological Research | Bruckers L.,Hasselt University | And 8 more authors.
Environment International | Year: 2010

Flanders is densely populated with much industry and intensive farming. Body size of 14- to 15-year old adolescents and of adults aged 50-65 was studied in relation to internal exposure to pollutants. 1679 adolescents (887 boys and 792 girls), 775 men and 808 women were selected as a random sample of the population. Concentrations of pollutants in blood or urine were measured in accordance with quality control/quality assurance procedures. Self-assessment questionnaires provided information on personal and life-style factors. Height and weight of subjects were measured. Confounding factors and significant covariates were taken into account. For boys and girls, height and body mass index (BMI) showed a negative association with urinary concentration of cadmium and BMI also with serum concentration of hexachlorobenzene (HCB) and with the sum of serum concentrations of polychlorinated biphenyls (PCBs) 138, 153, and 180 (marker PCBs), whereas BMI showed a positive association with serum concentration of PCB 118. For boys, height showed a negative association with urinary concentration of 1-hydroxypyrene (1-OHP) and positive associations with serum concentrations of HCB and PCB 118. For adults no significant associations between internal exposure and height were observed. For men, BMI showed negative associations with urinary cadmium concentration and with serum levels of marker PCBs and positive associations with serum levels of HCB, p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE), PCB 118 and the dioxin fraction of dioxin-like activity. For women, BMI showed a negative association with urinary cadmium concentration, with blood lead concentration and with the concentration of marker PCBs in serum, and a positive association with serum concentrations of HCB, p,p′-DDE and PCB 118. Associations between biological effects and internal exposures were, in terms of the regression coefficient, often stronger at exposures below the median. Environmental exposures to pollutants resulting in "normal" levels of internal exposure were associated with quite substantial differences in body mass index. © 2010 Elsevier Ltd. Source


Dhooge W.,Ghent University | Den Hond E.,Flemish Institute for Technological Research | Koppen G.,Flemish Institute for Technological Research | Bruckers L.,Hasselt University | And 8 more authors.
Journal of Exposure Science and Environmental Epidemiology | Year: 2011

Flanders is densely populated with much industry and intensive farming. Hormonal status of 14- to 15-year-old male adolescents was studied in relation to internal exposure to pollutants. A total of 887 participants were selected as a random sample of the adolescents residing in the study areas. Confounding factors and significant covariates were taken into account. Serum levels of testosterone, free testosterone and estradiol, and the aromatase index showed significant positive associations with serum levels of marker polychlorobiphenyls (sum of PCBs 138, 153, and 180) and of hexachlorobenzene (HCB) and a negative association with urinary cadmium concentration. Serum levels of estradiol also showed a positive association with serum levels of dichlorodiphenyldichloroethylene (DDE). A doubling of serum concentrations of marker PCBs and HCB and of urinary concentration of cadmium were, respectively, associated with an increase of 16.4% (P < 0.00001) and 16.6% (P < 0.001) and a decrease of 9.6% (P < 0.001) in serum testosterone concentration. Similar findings were made after additional adjustment for concurrent exposures. Associations between biological effects and internal exposures were, in terms of the regression coefficient, often stronger at exposures below the median. Environmental exposures to pollutants resulting in normal levels of internal exposure were associated with quite substantial differences in hormone concentrations. © 2011 Nature America, Inc. All rights reserved. Source

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