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Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children.

ABSTRACT: Polycyclic aromatic hydrocarbons (PAHs), the by-products of incomplete combustion of organic materials, are commonly found on particulate matter (PM) and have been associated with the development of asthma and asthma exacerbation in urban populations. We examined time spent in the home and outdoors as predictors of exposures to airborne PAHs and measured urinary 1-hydroxypyrene-glucuronide (1-OHPG) as internal dose of PAHs in 118 children aged 5-12 years from Baltimore, MD. During weeklong periods (Saturday-Saturday) in each of four seasons: daily activities were assessed using questionnaires, indoor air nicotine and PM concentrations were monitored, and urine specimens were collected on Tuesday (day 3) and Saturday (day 7) for measurement of 1-OHPG. Time spent in non-smoking homes was associated with significantly decreased 1-OHPG concentration in urine (?=-0.045, 95% CI (-0.076, -0.013)), and secondhand smoke (SHS) exposures modified these associations, with higher urinary 1-OHPG concentrations in children spending time in smoking homes than non-smoking homes (P-value for interaction=0.012). Time spent outdoors was associated with increased urinary 1-OHPG concentrations (?=0.097, 95% CI (0.037, 0.157)) in boys only. Our results suggest that SHS and ambient (outdoor) air pollution contribute to internal dose of PAHs in inner city children.

SUBMITTER: Peters KO

PROVIDER: S-EPMC5516642 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children.

Peters Kamau O KO Williams D' Ann L AL Abubaker Salahadin S Curtin-Brosnan Jean J McCormack Meredith C MC Peng Roger R Breysse Patrick N PN Matsui Elizabeth C EC Hansel Nadia N NN Diette Gregory B GB Strickland Paul T PT

Journal of exposure science & environmental epidemiology 20161214 3

Polycyclic aromatic hydrocarbons (PAHs), the by-products of incomplete combustion of organic materials, are commonly found on particulate matter (PM) and have been associated with the development of asthma and asthma exacerbation in urban populations. We examined time spent in the home and outdoors as predictors of exposures to airborne PAHs and measured urinary 1-hydroxypyrene-glucuronide (1-OHPG) as internal dose of PAHs in 118 children aged 5-12 years from Baltimore, MD. During weeklong perio ...[more]

PMID: 27966668

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Project description:BackgroundEpidemiological studies have found that prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with increased risk for neural tube defects (NTDs). Aberrant DNA methylation, excessive apoptosis, and oxidative stress have been implied as the mechanism underlying the association between PAH exposure and NTDs, respectively. However, the role of DNA methylation aberration of apoptotic initiator CASP8 (caspase-8, apoptosis-related cysteine peptidase) in the formation of NTDs in association with PAH exposure is not known. By combining a case-control study and mouse model, we aimed to explore the full spectrum of the links from PAH exposure, oxidative stress, CASP8 methylation change, caspase-8 activation, apoptosis, to NTD formation.ResultsHypomethylation of CASP8 promoter was noticed in the microarray profiled by Infinium HumanMethylation450 BeadChip using neural tissues from 10 terminated NTD fetuses and 8 terminated non-malformed fetuses (14 CpG sites, with β difference ranging between 8.8 and 26.3%), and was validated in a larger case-control sample performed with neural tissues from 80 NTD cases and 32 non-malformed fetuses, using the Sequenom MassARRAY system (7 CpG sites). Hypomethylation of CASP8 was a risk factor for NTDs (aOR = 1.11; 95% CI, 1.05-1.17) based on the logistic regression model. According to Pearson's correlation, methylation levels of CASP8 were inversely correlated with PAH concentrations in maternal serum and with oxidative stress markers in fetal neural tissues (p < 0.05). In the animal study, increased NTD rates (13.5% frequency), Casp8 hypomethylation, caspase-8 upregulation, increased caspase-8 cleavage, and excessive apoptosis were found in mouse embryos cultured with benz(a)pyrene (BaP) in vitro. Antioxidant N-acetyl-L-cysteine (NAC) and BaP co-treatment attenuated the changes found in BaP treatment group.ConclusionsHypomethylation of Casp8 promoter is associated with the formation of NTDs, and Casp8 hypomethylation may be induced by oxidative stress that resulted from exposure to PAHs.

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Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children.

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Predictors of polycyclic aromatic hydrocarbon exposure and internal dose in inner city Baltimore children.

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