Exposure to Polycyclic Aromatic Hydrocarbons, Plasma Cytokines, and Heart Rate Variability

Brain-derived neurotrophic factor (BDNF): an effect biomarker of neurodevelopment in human biomonitoring programs

The present narrative review summarizes recent findings focusing on the role of brain-derived neurotrophic factor (BDNF) as a biomarker of effect for neurodevelopmental alterations during adolescence, based on health effects of exposure to environmental chemical pollutants. To this end, information was gathered from the PubMed database and the results obtained in the European project Human Biomonitoring for Europe (HBM4EU), in which BDNF was measured at two levels of biological organization: total BDNF protein (serum) and BDNF gene DNA methylation (whole blood) levels. The obtained information is organized as follows. First, human biomonitoring, biomarkers of effect and the current state of the art on neurodevelopmental alterations in the population are presented. Second, BDNF secretion and mechanisms of action are briefly explained. Third, previous studies using BDNF as an effect biomarker were consulted in PubMed database and summarized. Finally, the impact of bisphenol A (BPA), metals, and non-persistent pesticide metabolites on BDNF secretion patterns and its mediation role with behavioral outcomes are addressed and discussed. These findings were obtained from three pilot studies conducted in HBM4EU project. Published findings suggested that exposure to some chemical pollutants such as fine particle matter (PM), PFAS, heavy metals, bisphenols, and non-persistent pesticides may alter circulating BDNF levels in healthy population. Therefore, BDNF could be used as a valuable effect biomarker to investigate developmental neurotoxicity of some chemical pollutants.

Assessment of the temporal variability and health risk of atmospheric particle-phase polycyclic aromatic hydrocarbons in a northeastern city in China

In this study, we examined the sources and temporal variability of 16 polycyclic aromatic hydrocarbons (PAHs) found in fine particulate matter (PM_2.5) in a typical industrial city in northern China. We also evaluated the incremental lifetime cancer risk (ILCR) from the inhalation of these PAHs. Atmospheric PM_2.5 samples were collected for 7 consecutive days each month from 2014 to 2019, and the 16 PAHs were measured using multiplex gas chromatography-tandem mass spectrometry. The carcinogenic risk of PAH exposure was assessed using the inhalation unit risk (IUR) and cancer slope factor (CSF) methods. The annual average concentrations of PM_2.5 for each year from 2014 to 2019 were 102.87±55.25, 86.92±60.43, 69.17±37.74, 58.20±59.15, 56.01±34.52, and 52.54±58.15 µg m^-3, and the annual average ΣPAH concentrations were 56.03±81.09, 47.99±79.30, 40.41±57.31, 33.57±51.79, 43.23±74.80, and 25.20±50.91 ng m^-3, respectively. Source identification, using diagnostic ratio analysis, indicated that the major PAH sources were coal/biomass combustion, fuel combustion, and traffic emissions. A health risk assessment showed that the ILCR from PAH inhalation decreased throughout the study period and varied with age. The IUR and CSF methods both showed that the adult ILCR exceeded 1.0×10^-6. These findings demonstrate the importance of addressing the carcinogenic risk of PM_2.5-bound PAHs, particularly in adults.

The Association between Urinary Polycyclic Aromatic Hydrocarbons Metabolites and Type 2 Diabetes Mellitus

Polycyclic aromatic hydrocarbons (PAHs) are considered to be endocrine disruptors. In this study, the evidence on the association between PAHs and diabetes was systematically reviewed. PubMed, EMBASE, and ISI Web of Science were systematically searched for studies reporting the association between PAHs and diabetes. Of the 698 articles identified through the search, nine cross-sectional studies were included. Seven were conducted in the general population and two in coke oven workers. Fixed-effects and random-effects models were used to calculate the total effect. Subgroup analysis was further carried out according to the types of PAH metabolites. The results showed that the odds of diabetes were significantly higher for the highest category of urinary naphthalene (NAP), fluorine (FLU), phenanthrene (PHEN), and total mono-hydroxylated (OH-PAH) metabolites compared to the lowest category. The pooled odds ratios (OR) and 95% confidence intervals (CI) were 1.52 (95%CI: 1.19, 1.94), 1.53 (95%CI: 1.36, 1.71), 1.43 (95%CI: 1.28, 1.60), and 1.49 (95%CI: 1.07, 2.08), respectively. In coke oven workers, 4-hydroxyphenanthrene (4-OHPh) was significantly correlated with an increased risk of diabetes. Exposure measurements, outcome definitions, and adjustment for confounders were heterogeneous between studies. The results of the current study demonstrate a potentially adverse effect of PAHs on diabetes. Further mechanistic studies and longitudinal studies are needed to confirm whether PAH metabolite levels are causative, and hence associative, with increased diabetes incidences.

Relationship of polycyclic aromatic hydrocarbons exposure with vascular damages among sanitation workers

Chronic exposure to polycyclic aromatic hydrocarbons (PAHs) leads to a high incidence of cardiovascular diseases. To assess the effects of PAHs exposure on vascular damages in occupationally exposed populations, 196 sanitation workers were recruited. According to the differences of occupation or operation, they were divided into exposure group (n = 115) and control group (n = 81). Sixteen serum PAHs were determined by gas chromatography-tandem mass spectrometery. Tumor necrosis factor ɑ (TNF-ɑ) and angiotensin II (ANG-II) in serum, blood lipids and blood pressure were also measured. Results showed that, except for indeno(1,2,3-cd)pyrene, dibenzo(a,h)anthracene and benzo(g,h,i)perylene, the detection frequencies of other PAHs were above 85%, showing that subjects are generally exposed to PAHs. The top three compounds in serum concentrations of PAHs were phenanthrene, acenaphthylene and anthracene. Moreover, the concentrations of total serum PAHs in the exposure group were significantly higher than those in the control (p < 0.05), suggesting a higher PAHs exposure in the former. Though there was no significant difference in blood lipids and blood pressure between groups (p > 0.05), TNF-ɑ and ANG-II levels in the exposure group were significantly higher than those in the control group (p < 0.05), suggesting that PAHs exposure may be related to pro-inflammatory effects and vascular endothelial damages.

The effect of polycyclic aromatic hydrocarbons on changes in the brain structure of firefighters: An analysis using data from the Firefighters Research on Enhancement of Safety & Health study

Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete combustion of organic matter, and firefighters are highly exposed to these toxic compounds at fire sites. Exposure to PAHs can cause cognitive decline and neurodegeneration; however, to date, few studies have examined the potential effects of PAH exposure on structural changes in the brain. We aimed to investigate the association between the four types of PAH metabolites and the corresponding changes in neuroimaging markers based on smoking status and hypertension in male firefighters. For this, we utilized the 2-year follow-up data of 301 Korean male firefighters aged over 40 years. The concentrations of four PAH metabolites in urine were measured. Subcortical volume and cortical thickness were estimated using 3 T magnetic resonance imaging of the brain. A generalized linear model was used to investigate the effects of PAHs on changes in the subcortical volume and cortical thickness. We found an association between 1-hydroxyphenathrene (1-OHPHE) and 2-hydroxyfluorene (2-OHF) and changes in several brain regions in all the study participants. Individuals who had never smoked showed significantly thinner frontal (p < 0.001), parietal (p < 0.001), temporal (p < 0.001), and cingulate lobes (p < 0.001) with 1% increase each in the urinary concentration of 1-OHPHE. Hypertension interacted with the concentration of 1-OHPHE to reduce the volume of gray matter and cause cortical thinning in the frontal, parietal, and temporal lobes. Exposure to PAHs may reduce cortical thickness and subcortical volume, which are definitive markers of neurodegeneration. Notably, hypertension can accelerate the degenerative effects of PAHs.

Longitudinal relationships between polycyclic aromatic hydrocarbons exposure and heart rate variability: Exploring the role of transforming growth factor-β in a general Chinese population

We aim to investigate the long-term adverse effects of polycyclic aromatic hydrocarbons (PAHs) exposure on heart rate variability (HRV) reduction, and to assess the potential role of transforming growth factor-β1 (TGF-β1) in such relationship. We enrolled 2985 adult residents with 4100 observations who participated at baseline and 6-years follow-up from Wuhan-Zhuhai cohort. Ten detectable urinary PAHs metabolites and two HRV indices were repeatedly measured at baseline and follow-up; and plasma TGF-β1 levels were also determined for all subjects. We observed that both total urinary low molecular weight PAHs (ΣLWM OH-PAH) and total urinary high molecular weight PAHs (ΣHWM OH-PAH) were negatively associated with HRV reductions (P < 0.05). Subjects with persistent high levels of ΣHWM OH-PAH had a significant reduction in HRV over 6 years, and the incensement of TGF-β1 could aggravate above adverse effects in a dose-response manner. All kinds of PAHs were positively associated with plasma TGF-β1 elevation, which in turn, were negatively related to HRV indices. Increased TGF-β1 significant mediated 1.34-3.62% of PAHs-associated HRV reduction. Our findings demonstrated that long-term high levels of PAHs exposure could cause HRV reductions, and TGF-β1 may play an essential role in such association.

Relationship Between Polycyclic Aromatic Hydrocarbons and Cardiovascular Diseases: A Systematic Review

Objective: The primary aim of this systematic review was to examine the relationship of polycyclic aromatic hydrocarbon (PAH) exposure with cardiovascular diseases (CVDs) and elaborate the current knowledge and recent advances in the area of PAH and its effects on CVDs and discuss the growing epidemiological evidence linking PAH to CVDs on the health of human populations. In this systematic review, the increased risk of cardiovascular diseases and their relationship with PAHs were discussed in detail.

Methods: On 05th April 2021, a systematic literature search was conducted using PubMed/Medline and Web of Science search engines in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. The search was limited to articles that were written in English and dealt with human issues. All original peer-review publications were considered for inclusion. Comments, case reports, reviews, duplicated papers, and conference reports were excluded. Data was collected from included papers by two independent reviewers.

Results: Conclusively, 20 research articles published between 2005 and 2021 were chosen for the final analysis. The systemic review included 20 studies with a variety of geographical studies. The most common research category among the nominated studies were time-series studies followed by retrospective cohort, cross-sectional, quasi-experimental, panel, and case-control studies. Most of the studies were conducted in the United States, whereas others were showed in various geographical countries around the world, such as Denmark, Germany, Finland, Netherlands, France, China, Norway, Korea, Sweden, Saudi Arabia, and Belgium. Eight studies assessed the association between PAH exposure and CVDs, four articles observed this relationship with blood pressure (BP), two observed association between atherosclerotic CVD and PAH, one congenital heart disease, cardiovascular events, and two with obesity. Furthermore, in some investigations, a favorable association between PAH exposure and hypertension as well as PAH exposure and obesity was found.

Conclusion: In conclusion, this systematic review examined the relationship of PAH exposure with CVDs and CVD-related risk factors by searching several digital databases. After a comprehensive literature searches and summarizing findings from 20 articles, the authors concluded that a positive relationship was observed between PAH exposure and CVD risks.

In utero exposure to mixed PAHs causes heart mass reduction in adult male mice

Polycyclic aromatic hydrocarbons (PAHs) are a risk factor for the occurrence of cardiac diseases. The present study was conducted to investigate the influence of prenatal exposure to a mixed PAHs on heart and the underlying mechanism. Pregnant mice were orally administered with a mixture of 8 kinds of PAHs (0, 5, 50, 500 μg/kg body weight) once every 2 days for a total of 8 dosages. The mixed PAHs contained naphthalene, acenaphthylene, phenanthrene, fluoranthene, pyrene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene at a weight ratio of 10: 10: 10: 10: 10: 1: 1: 1. The adult males, not females, showed significantly decreased heart/body weight ratio, which was attributed to the loss of cardiac fiber and the increase of cell apoptosis. The protein expression of transforming growth factor β1 and its downstream transcription factors, Smad3 and Smad4, was significantly downregulated, which caused the loss of cardiac fiber. The downregulated phosphatidylinositol 3-kinase and AKT led to increased expression of caspase3, caspase9, BAX and reduced expression of Bcl-2, which was responsible for the increased cell apoptosis. Different levels of aromatic hydrocarbon receptor and sex hormone receptors between males and females were associated with the distinct effect on heart.

Association among blood BPDE-DNA adduct, serum interleukin-8 (IL-8) and DNA strand breaks for children with pulmonary diseases

Exposure to benzo[a]pyrene (B[a]P) may be a risk factor for pulmonary diseases. To investigate the correlations among B[a]P exposure level, DNA strand breaks and pulmonary inflammation, we recruited 83 children diagnosed with pulmonary diseases and 63 healthy children from Guangzhou, China. Results showed that the levels of Benzo[a]pyrene diol epoxide (BPDE) DNA adduct in blood and IL-8 in serum in case group were significantly higher than those in control group (p < 0.01). Moreover, levels of atmospheric B[a]P in case group was about twice of those in control group, which was consistent with the levels of BPDE-DNA adduct in blood. Significant positive correlations were observed among the levels of BPDE-DNA adduct, IL-8 and DNA strand breaks (p < 0.05). Our findings indicate that environmental air is an important exposure source of B[a]P and higher B[a]P exposure may contribute to the occurrence of pulmonary inflammation and lead to high health risks.

The interaction effects of FEN1 rs174538 polymorphism and polycyclic aromatic hydrocarbon exposure on damage in exon 19 and 21 of EGFR gene in coke oven workers

Polycyclic aromatic hydrocarbon (PAH) exposure and genetic susceptibility were conductive to genotoxic effects including gene damage, which can increase mutational probability. We aimed to explore the dose-effect associations of PAH exposure with damage of exons of epidermal growth factor receptor (EGFR) and breast cancer susceptibility gene 1 (BRCA1), as well as their associations whether modified by Flap endonuclease 1 (FEN1) genotype. Two hundred eighty-eight coke oven male workers were recruited, and we detected the concentration of 1-hydroxypyrene (1-OH-pyr) as PAH exposure biomarker in urine and examined base modification in exons of EGFR and BRCA1 respectively, and genotyped FEN1 rs174538 polymorphism in plasma. We found that the damage indexes of exon 19 and 21 of EGFR (EGFR-19 and EGFR-21) were both significantly associated with increased urinary 1-OH-pyr (both Ptrend < 0.001). The levels of urinary 1-OH-pyr were both significantly associated with increased EGFR-19 and EGFR-21 in both smokers and nonsmokers (both P < 0.001). Additionally, we observed that the urinary 1-OH-pyr concentrations were linearly associated with both EGFR-19 and EGFR-21 only in rs174538 GA+AA genotype carriers (both P < 0.001). Moreover, FEN1rs rs174538 showed modifying effects on the associations of urinary 1-OH-pyr with EGFR-19 and EGFR-21 (both Pinteraction < 0.05). Our findings revealed the linear dose-effect association between exon damage of EGFR and PAH exposure and highlight differences in genetic contributions to exon damage and have the potential to identify at-risk subpopulations who are susceptible to adverse health effects induced by PAH exposure.

Circulating microRNAs as biomarkers of environmental exposure to polycyclic aromatic hydrocarbons: potential and prospects

Exposure to polycyclic aromatic hydrocarbons (PAHs) produced from various pyrogenic and petrogenic sources in the environment has been linked to a variety of toxic effects in the human body. Genome-wide analyses have shown that microRNAs (miRNAs) can function as novel and minimally invasive biomarkers of environmental exposure to PAHs. The objective of this study is to explore miRNA signatures associated with early health effects in response to chronic environmental exposure to PAHs. We systematically searched Scopus and PubMed databases for studies related to exposure of PAHs with changes in miRNA expression patterns that represent early health effects in the exposed population. Based on previous studies, we included 15 cell-based and 9 each of animal model and human population-based studies for assessment. A total of 11 differentially expressed PAH-responsive miRNAs were observed each in two or more cell-based studies (miR-181a and miR-30c-1), animal model studies (miR-291a and miR-292), and human population-based studies (miR-126, miR-142-5p, miR-150-5p, miR-24-3p, miR-27a-3p, miR-28-5p, and miR-320b). In addition, miRNAs belonging to family miR-122, miR-199, miR-203, miR-21, miR-26, miR-29, and miR-92 were found to be PAH-responsive in both animal model and cell-based studies; let-7, miR-126, miR-146, miR-30, and miR-320 in both cell-based and human population-based studies; and miR-142, miR-150, and miR-27 were found differentially expressed in both animal model and human population-based studies. The only miRNA whose expression was found to be altered in all the three groups of studies is miR-34c. Association of environmental exposure to PAHs with altered expression of specific miRNAs indicates that selective miRNAs can be used as early warning biomarkers in PAH-exposed population.

E-waste polycyclic aromatic hydrocarbon (PAH) exposure leads to child gut-mucosal inflammation and adaptive immune response

Polycyclic aromatic hydrocarbon (PAH) exposure alters immunological responses. Research concerning PAH exposure on intestinal immunity of children in electronic waste (e-waste) areas is scarce. The aim of this study was to evaluate the effects of polycyclic aromatic hydrocarbon (PAH) pollutants on intestinal mucosal immunity of children in e-waste areas. Results showed higher hydroxylated PAH (OH-PAH) concentrations in e-waste-exposed children, accompanied with higher sialyl Lewis A (SLA) level, absolute lymphocyte and monocyte counts, decreased of percentage of CD4⁺ T cells, and had a higher risk of diarrhea. OH-PAH concentrations were negative with child growth. 1-OHNap mediated through WBCs, along with 1-OHPyr, was correlated with an increase SLA concentration. 2-OHFlu, 1-OHPhe, 2-OHPhe, 1-OHPyr, and 6-OHChr were positively correlated with secretory immunoglobulin A (sIgA) concentration. Our results indicated that PAH pollutants caused inflammation, affected the intestinal epithelium, and led to transformation of microfold cell (M cell). M cells initiating mucosal immune responses and the subsequent increasing sIgA production might be an adaptive immune respond of children in the e-waste areas. To our knowledge, this is the first study of PAH exposure on children intestinal immunity in e-waste area, showing that PAH exposure plays a negative role in child growth and impairs the intestinal immune function.

Polycyclic aromatic hydrocarbons associated long non-coding RNAs and heart rate variability in coke oven workers

Epidemiological studies have showed that polycyclic aromatic hydrocarbons (PAHs) were associated with heart rate variability (HRV), but the role of long non-coding RNAs (lncRNAs) in the association is unknown. We aimed to identify PAHs-related lncRNAs and assess their associations with HRV among coke oven workers. Differential lncRNAs expression between 12 exposed workers and 12 controls was tested by Human 8X60k LncRNA Arrays in discovery stage, then selected NR_024564 was validated in 353 workers using droplet digital RT-PCR. Microarray results showed that 1234 lncRNAs were downregulated with 805 lncRNAs upregulated in exposed group (≥ 2-fold change). In validation stage, no significant association was observed between NR_024564 and PAH exposure or HRV in total subjects, while urinary 2-hydroxyfluorene (2-OHFlu) was inversely related to root mean square successive difference (RMSSD). However, in current smokers, NR_024564 was inversely related to urinary 2-OHFlu, 2-hydroxyphenanthrene, 1-hydroxypyrene (1-OHP), and total PAHs metabolites (ΣOH-PAHs), of which 1-OHP accounted for the strongest estimation for interaction with smoking status (P_interaction = 0.011). Also, the positive associations of NR_024564 with RMSSD and high frequency power showed an interaction with smoking status (P_interaction = 0.034 and 0.023, respectively). Also, urinary 2-OHFlu and ΣOH-PAHs were inversely associated with RMSSD in current smokers. In addition, elevated NR_024564 was dose-responsive related to increased RMSSD in above high-PAHs groups among smokers (all P_trend < 0.05). Our results revealed that NR_024564 and its interactions with smoking status might act as novel mechanisms regulating the adverse effects of PAHs on HRV.

Polycyclic aromatic hydrocarbons and development of respiratory and cardiovascular diseases in workers

OBJECTIVES

to identify the scientific evidence on the development of cardiovascular and respiratory diseases due to workplace contamination by polycyclic aromatic hydrocarbons.

METHODS

integrative literature review. The search for primary articles was held in October 2017 in the Medical Literature Analysis and Retrieval System Online (through Pubmed), Web of Science and Latin American and Caribbean Literature in Health Sciences (LILACS).

RESULTS

the 16 studies analyzed showed that exposure to polycyclic aromatic hydrocarbons was associated with cardiovascular diseases, such as increased blood pressure, heart rate variation, and ischemic heart disease; and respiratory disorders, such as decreased lung function, chronic obstructive pulmonary disease, asthma, wheeze, coughing, pulmonary wheezing, chest tightness, effort dyspnea, and sore throat.

CONCLUSIONS

polycyclic aromatic hydrocarbons cause deleterious effects on the cardiovascular and respiratory systems through mutations and cellular inflammation, being a risk to exposed individuals.

A multi-stage association study of plasma cytokines identifies osteopontin as a biomarker for acute coronary syndrome risk and severity

Cytokines play a critical role in the pathogenesis and development of cardiovascular diseases. However, data linking cytokines to risk and severity of acute coronary syndrome (ACS) are still limited. We measured plasma profile of 280 cytokines using a quantitative protein microarray in 12 ACS patients and 16 healthy controls, and identified 15 differentially expressed cytokines for ACS. Osteopontin, chemokine ligand 23, brain derived neurotrophic factor and C-reactive protein (CRP) were further validated using immunoassay in two independent case-control studies with a total of 210 ACS patients and 210 controls. We further examined their relations with incident ACS among 318 case-control pairs nested within the Dongfeng-Tongji cohort, and found plasma osteopontin and CRP concentrations were associated with incident ACS, and the multivariable-adjusted odds ratio (95% confidence interval) was 1.29 (1.06-1.57) per 1-SD increase for osteopontin and 1.30 (1.02-1.66) for CRP, respectively. Higher levels of circulating osteopontin were also correlated with higher severity of ACS, and earlier ACS onset time. Adding osteopontin alone or in combination with CRP modestly improved the predictive ability of ACS beyond the Framingham risk scores. Our findings suggested that osteopontin might be a biomarker for incident ACS, using osteopontin adds moderately to traditional cardiovascular risk factors.

Household coal combustion, indoor air pollutants, and circulating immunologic/inflammatory markers in rural China

The study aim was to investigate whether household bituminous ("smoky") coal use and personal exposure to combustion emissions were associated with immunologic/inflammatory marker levels. A cross-sectional study of healthy never-smoking women from rural Xuanwei and Fuyuan, China was conducted, which included 80 smoky coal and 14 anthracite ("smokeless") coal users. Personal exposure to fine particulate matter (PM_2.5) and benzo[a]pyrene (BaP) was assessed using portable devices, while 67 circulating plasma immunologic/inflammatory markers were measured using multiplex bead-based assays. Multivariable linear regression models were employed to estimate associations between smoky coal versus smokeless coal use, indoor air pollutants, and immunologic/inflammatory markers. Six markers were altered among smoky coal users compared to smokeless coal, including significantly decreased interferon-inducible T-cell alpha chemoattractant (CXCL11/I-TAC), and increased serum amyloid P component (SAP). CXCL11/I-TAC was previously found to be reduced in workers exposed to high levels of diesel engine exhaust, which exhibits similar constituents as coal combustion emissions. Further, there was evidence that elevated PM_2.5 and BaP exposure was associated with significantly diminished levels of the serum amyloid A (SAA); however, the false discovery rates (FDRs) were >0.2 after accounting for multiple comparisons. Inflammatory processes may thus mediate the carcinogenic effects attributed to smoky coal emissions.

Arsenic exposure assists ccm3 genetic polymorphism in elevating blood pressure

Epidemiologic study has suggested that arsenic exposure is positively related to increased blood pressure. However, the underlying mechanism concerning interaction between genetic polymorphisms and arsenic exposure remains unclear. In present study, within 395 Chinese, the effects of interaction between arsenic exposure and CCM3 gene polymorphisms on elevation of blood pressure were probed by multiple Logistic regression models after adjusting for confounding factors. Firstly, we found that serum arsenic was positively associated with blood pressure, cholesterol, glucose and C-reactive protein. Then, adjusted for confounding factors of age, gender, smoking, alcohol consumption, BMI and degree of education, arsenic exposure incurred the hazard of increased systolic pressure and diastolic pressure, with odds ratios (ORs) being 1.725 and 1.425, respectively. Distinctly, we found that interactions between rs3804610^* rs9818496, rs6784267^*rs9818496, and rs3804610^* rs6784267 variant genotype can increase significantly risks of SBP. Additionally, interactions between rs9818496, rs3804610 and rs6784267 genotypic variantions and arsenic exposure boosted the hazard of increased systolic pressure, with ORs being 1.496, 1.496 and 1.312. In conclusion, our fingdings suggest that As exposure of population can assist CCM3 polymorphism in elevating SBP.

Early markers of cardiovascular disease are associated with occupational exposure to polycyclic aromatic hydrocarbons

Occupational exposure to soot, rich in polycyclic aromatic hydrocarbons (PAH), has been associated with increased risk of cardiovascular disease (CVD). However, our knowledge about PAH exposure and early markers of CVD remains limited. In this cross-sectional study of 151 chimney sweeps and 152 controls, we investigated occupational exposure to PAH and early markers of CVD. Blood pressure (BP) (chimney sweeps only), urinary PAH metabolites and serum biomarkers were measured (C-reactive protein, homocysteine, gamma-glutamyltransferase, cholesterol, HDL, LDL, and triglycerides). Chimney sweeps had up to 7 times higher concentrations of PAH metabolites in urine than controls (P < 0.001): median concentrations (adjusted for specific gravity) for 1-hydroxypyrene, 2-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, and 3-hydroxybenzo[a]anthracene were 0.56 µg/L, 0.78 µg/L, 4.75 ng/L, and 6.28 ng/L, respectively. Compared with controls, chimney sweeps had increased homocysteine, cholesterol, and HDL (β = 3.4 µmol/L, 0.43 mmol/L, and 0.13 mmol/L, respectively, P ≤ 0.003, adjusted for age, BMI, and smoking). In chimney sweeps, PAH metabolites correlated positively with the percentage of soot sweeping (P < 0.001). 2-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, and 3-hydroxybenzo[a]anthracene were positively associated with diastolic BP (P < 0.044, adjusted for age, BMI, and smoking). PAH exposure among chimney sweeps resulted in elevated levels of markers for CVD risk. These findings stress the need to reduce occupational exposure to PAH.

Urinary Polycyclic Aromatic Hydrocarbon Metabolite Associations with Biomarkers of Inflammation, Angiogenesis, and Oxidative Stress in Pregnant Women

Environmental exposure to polycyclic aromatic hydrocarbons (PAHs) is prevalent and may adversely impact pregnancy and development of the fetus. The purpose of this exploratory study was to examine urinary PAH metabolites in potential association with mediators of these outcomes. To do so, we measured a panel of 12 inflammatory, angiogenic, and oxidative stress biomarkers in plasma or urine from women in their third trimester of pregnancy (n = 200). Urinary PAH metabolites were highly detectable (>88%) in the study population, and most were higher in women who had lower education levels, higher body mass index, and who were African-American. Some PAH metabolites showed consistent positive associations with the plasma inflammation marker C-reactive protein (CRP) and the urinary oxidative stress markers 8-hydroxydeoxyguanosine (8-OHdG) and 8-isoprostane. For example, an interquartile range increase in 2-hydroxynapthalene was associated with a 35% increase in CRP (95% confidence interval = -0.13, 83.2), a 14% increase in 8-OHdG (95% confidence interval =0.59, 30.1), and a 48% increase in 8-isoprostane (95% confidence interval =16.7, 87.0). These data suggest that exposure to PAHs may cause systemic changes during pregnancy that could lead to adverse pregnancy or developmental outcomes; however, these results should be corroborated in a larger study population.

A Systematic Review on the Effects of Polycyclic Aromatic Hydrocarbons on Cardiometabolic Impairment

Background:

Various epidemiological studies have shown that exposure to environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) might increase the risk of cardiovascular diseases (CVDs) and their risk factors. This study aims to systematically review the association of PAH exposure with metabolic impairment.

Methods:

Data were collected by searching for relevant studies in international databases using the following keywords: “polycyclic aromatic hydrocarbon” + “cardiovascular disease,” PAH + CVD, polycyclic aromatic hydrocarbon and “air pollutant” + “CVD,” and the desired data were extracted and included in the study according to the systematic review process.

Results:

From the 14 articles included in the present systematic review, eight articles were conducted on the relationship between PAH and CVDs, four articles were conducted to examine the association of PAH exposure with blood pressure (BP), and two articles investigated the link between PAH and obesity.

Conclusions:

Most studies included in this systematic review reported a significant positive association of PAH exposure with increased risk of CVDs and its major risk factors including elevated BP and obesity. These findings should be confirmed by longitudinal studies with long-term follow-up.

Polycyclic aromatic hydrocarbon exposure, miR-146a rs2910164 polymorphism, and heart rate variability in coke oven workers

BACKGROUND

Exposure to ubiquitous polycyclic aromatic hydrocarbons (PAHs) has been associated with decreased heart rate variability (HRV). Evidence accumulates that microRNAs (miRNAs) might be the intermediate factors between environmental exposures and their adverse health effects. Single nucleotide polymorphisms (SNPs) in miRNA genes may affect phenotypes and disease morbidity.

OBJECTIVE

We sought to investigate the influences of four well-studied SNPs in miRNA genes (rs2910164, rs11614913, rs2292832, and rs3746444) on HRV, and their modifying effects on the associations between PAH exposure and HRV.

METHODS

We measured the concentrations of ten urinary monohydroxy PAHs (OH-PAHs), seven HRV parameters, and genotypes of these four SNPs in 1222 coke oven workers.

RESULTS

There were significant differences among different rs2910164 genotype carriers in terms of all seven HRV indices: workers with rs2910164 CC genotype had significant lower HRV than those with GG or GC genotype (P<0.05). The number of rs2910164 C allele was negatively associated with HRV indices in the high PAH exposure group (β<0, P<0.05), and the association between rs2910164 and high-frequency (HF) power was significantly stronger in high exposure group (Pinteraction=0.042). Interestingly, the negative associations between the sum of 10 OH-PAHs and HRV (β<0, P<0.05) were significantly or marginally significantly stronger in workers with rs2910164 CC genotype (Pinteraction≤0.050).

CONCLUSIONS

Coke oven workers with miR-146a rs2910164 CC genotype may be more susceptible to decreased HRV. The modifying effect of rs2910164 on the PAHs-HRV associations suggested miR-146a may mediate the effects of PAH exposure on HRV.