Polycyclic Aromatic Hydrocarbons–Associated MicroRNAs and Heart Rate Variability in Coke Oven Workers

Genetic and epigenetic modulations in toxicity: The two-sided roles of heavy metals and polycyclic aromatic hydrocarbons from the environment

This study emphasizes the importance of considering the metabolic and toxicity mechanisms of environmental concern chemicals in real-life exposure scenarios. Furthermore, environmental chemicals may require metabolic activation to become toxic, and competition for binding sites on receptors can affect the severity of toxicity. The multicomplex process of chemical toxicity is reflected in the activation of multiple pathways during toxicity of which AhR activation is major. Real-life exposure to a mixture of concern chemicals is common, and the composition of these chemicals determines the severity of toxicity. Nutritional essential elements can mitigate the toxicity of toxic heavy metals, while the types and ratio of composition of PAH can either increase or decrease toxicity. The epigenetic mechanisms of heavy metals and PAH toxicity involves either down-regulation or up-regulation of some non-coding RNAs (ncRNAs) whereas specific small RNAs (sRNAs) may have dual role depending on the tissue and circumstance of expression. Similarly, decrease DNA methylation and histone modification are major players in heavy metals and PAH mediated toxicity and FLT1 hypermethylation is a major process in PAH induced carcinogenesis. Overall, this review provides the understanding of the metabolism of environmental concern chemicals, emphasizing the importance of considering mixed compositions and real-life exposure scenarios in assessing their potential effects on human health and diseases development as well as the dual mechanism of toxicity via genetic or epigenetic axis.

Polycyclic aromatic hydrocarbons exposure and arterial stiffness-related plasma miRNAs: A panel study

The underlying mechanisms between polycyclic aromatic hydrocarbons (PAHs) exposure and arterial stiffness are poorly understood. We carried out a panel study involving three repeated surveys to examine the associations of individual and mixture of PAHs exposure with arterial stiffness-related miRNAs among 123 community adults. In linear mixed-effect (LME) models, we found that urinary 9-hydroxyfluorene (9-OHFlu), 2-hydroxyphenanthrene (2-OHPh), 9-hydroxyphenanthrene (9-OHPh) at lag 0 day were positively linked to miR-146a and/or miR-222. The Bayesian kernel machine regression (BKMR) analyses revealed positive overall associations of PAHs mixture at lag 0 day with miR-146a and miR-222, and urinary 9-OHFlu contributed the most. In addition, an inter-quartile range (IQR) increase in urinary 9-OHFlu at lag 0 day was associated with elevated miR-146a and miR-222 by 0.16 (95% CI: 0.02, 0.30) to 0.34 (95% CI: 0.13, 0.54). Accordingly, exposure to PAHs, especially 9-OHFlu at lag 0 day, was related to elevated arterial stiffness-related plasma miRNAs.

Association between occupational noise exposure duration and heart rate variability among Chinese adults: The role of plasma miRNAs

We aimed to explore the association between occupational noise exposure duration and heart rate variability (HRV) and the underlying mechanism. A total of 449 subjects in a manufacturing company in Wuhan, China were included in our study and six candidate miRNAs (miR-200a-3p, miR-200b-3p, miR-200c-3p, miR-1-3p, miR-92a-3p and miR-21-5p) were tested among 200 individuals. Information combining the work histories and the occupational noise monitoring records were used to calculate the exposure of occupational noise, HRV indices were measured by using 3-channel digital Holter monitors, including the standard deviation of all normal R-R intervals (SDNN), the root mean of the square of successive differences between adjacent normal NN intervals (r-MSSD), SDNN index, low-frequency power (LF), high-frequency power (HF) and TP (total power). We found a significant linear negative dose-response relationship between occupational noise exposure duration and HRV indices (P for overall <0.05, P for nonlinear >0.05), including SDNN, r-MSSD, SDNN index, LF and HF. In the continuous models, the β (95% CIs) for each 1-year occupational noise exposure were -0.002 (-0.004, -0.001) for SDNN, -0.002 (-0.004, -0.001) for r-MSSD, -0.002 (-0.004, -0.001) for SDNN index, and -0.006 (-0.012, -0.001) for HF. Meanwhile, we also found that occupational noise exposure duration was significantly associated with lower expression of five miRNAs, when adjusting for other covariates. The β (95% CIs) were -0.039 (-0.067, -0.011) for miRNA-200c-3p, -0.053 (-0.083, -0.022) for miRNA-200a-3p, -0.044 (-0.070, -0.019) for miRNA-200b-3p, -0.032 (-0.048, -0.017) for miRNA-92a-3p, and -0.063 (-0.089, -0.038) for miRNA-21-5p in the continuous models. In addition, we found a positive association between miRNA-1-3p and LF (β = 0.039, 95% CI = 0.002, 0.080). Our study suggests that occupational noise exposure duration is associated with cardiac autonomic dysfunction, and the role of miRNAs in noise induced HRV reduction needs to be confirmed in future studies.

Influences of polycyclic aromatic hydrocarbon on the epigenome toxicity and its applicability in human health risk assessment

The existence of polycyclic aromatic hydrocarbons (PAHs) in ambient air is an escalating concern worldwide because of their ability to cause cancer and induce permanent changes in the genetic material. Growing evidence implies that during early life-sensitive stages, the risk of progression of acute and chronic diseases depends on epigenetic changes initiated by the influence of environmental cues. Several reports deciphered the relationship between exposure to environmental chemicals and epigenetics, and have known toxicants that alter the epigenetic states. Amongst PAHs, benzo[a]pyrene (B[a]P) is accepted as a group 1 cancer-causing agent by the International Agency for the Research on Cancer (IARC). B[a]P is a well-studied pro-carcinogen that is metabolically activated by the aryl hydrocarbon receptor (AhR)/cytochrome P450 pathway. Cytochrome P450 plays a pivotal role in the stimulation step, which is essential for DNA adduct formation. Accruing evidence suggests that epigenetic alterations assume a fundamental part in PAH-promoted carcinogenesis. This interaction between PAHs and epigenetic factors results in an altered profile of these marks, globally and locus-specific. Some of the epigenetic changes due to exposure to PAHs lead to increased disease susceptibility and progression. It is well understood that exposure to environmental carcinogens, such as PAH triggers disease pathways through changes in the genome. Several evidence reported due to the epigenome-wide association studies, that early life adverse environmental events may trigger widespread and persistent variations in transcriptional profiling. Moreover, these variations respond to DNA damage and/or a consequence of epigenetic modifications that need further investigation. Growing evidence has associated PAHs with epigenetic variations involving alterations in DNA methylation, histone modification, and micro RNA (miRNA) regulation. Epigenetic alterations to PAH exposure were related to chronic diseases, such as pulmonary disease, cardiovascular disease, endocrine disruptor, nervous system disorder, and cancer. This hormetic response gives a novel perception concerning the toxicity of PAHs and the biological reaction that may be a distinct reliance on exposure. This review sheds light on understanding the latest evidence about how PAHs can alter epigenetic patterns and human health. In conclusion, as several epigenetic change mechanisms remain unclear yet, further analyses derived from PAHs exposure must be performed to find new targets and disease biomarkers. In spite of the current limitations, numerous evidence supports the perception that epigenetics grips substantial potential for advancing our knowledge about the molecular mechanisms of environmental toxicants, also for predicting health-associated risks due to environmental circumstances exposure and individual susceptibility.

Polycyclic aromatic hydrocarbons, long non-coding RNA expression, and DNA damage in coke oven workers

Exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with DNA damage, while the roles of long non-coding RNAs (lncRNAs) in the associations were unclear. We aimed to assess the association of lncRNA NR_024564 with urinary monohydroxy PAHs (OH-PAHs) and DNA damage among 332 coke oven workers. We determined 12 OH-PAHs by gas chromatography-mass spectrometry, and the expression level of NR_024564 by droplet digital RT-PCR and DNA damage by the comet assay. In total participants, we found that NR_024564 was not significantly associated with OH-PAHs or comet parameters. However, among workers with ≥ 20 working years, multiple OH-PAHs including urinary 1-hydroxyphenanthrene (1-OHPh), 2-OHPh, 3-OHPh, 9-OHPh, 1‑hydroxypyrene, and total PAH metabolites were related to increased comet parameters. Moreover, NR_024564 was significantly associated with 2-OHPh and four comet parameters. Each 1% increase in 2-OHPh was associated with 0.35% reduction (95% CI: 0.16%, 0.55%) in NR_024564 (P-_FDR = 0.005), and 2-OHPh was marginally interacted with working years in relation to NR_024564 decrease. Also, each 1% increment of NR_024564 was related to 0.04-0.13% decrease of Olive tail moment, percent DNA in the comet tail, tail length, and tail moment (all P-_FDR < 0.05). Furthermore, low NR_024564 level combined with high levels of 1-OHPh and 2-OHPh or ≥ 20 working years was positively associated with the comet parameters among the total participants. Our results indicated that NR_024564 might be linked to the adverse associations of PAHs with the DNA damage of coke oven workers who worked for ≥ 20 years.

Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: An update of a systematic literature review

Epigenetic alterations, such as changes in DNA methylation, histones/chromatin structure, nucleosome positioning, and expression of non-coding RNAs, are recognized among key characteristics of carcinogens; they may occur independently or concomitantly with genotoxic effects. While data on genotoxicity are collected through standardized guideline tests, data collected on epigenetic effects is far less uniform. In 2016, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints to better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints. Since then, the number of studies of epigenetic effects of chemicals has nearly doubled. This review stands as an update on epigenetic alterations induced by occupational and environmental human carcinogens that were previously and recently classified as Group 1 by the International Agency for Research on Cancer. We found that the evidence of epigenetic effects remains uneven across agents. Studies of DNA methylation are most abundant, while reports concerning effects on non-coding RNA have increased over the past 5 years. By contrast, mechanistic toxicology studies of histone modifications and chromatin state alterations remain few. We found that most publications of epigenetic effects of carcinogens were studies in exposed humans or human cells. Studies in rodents represent the second most common species used for epigenetic studies in toxicology, in vivo exposures being the most predominant. Future studies should incorporate dose- and time-dependent study designs and also investigate the persistence of effects following cessation of exposure, considering the dynamic nature of most epigenetic alterations.

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.

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.

An Assessment on Ethanol-Blended Gasoline/Diesel Fuels on Cancer Risk and Mortality

Although cancer is traditionally considered a genetic disease, the epigenetic abnormalities, including DNA hypermethylation, histone deacetylation, and/or microRNA dysregulation, have been demonstrated as a hallmark of cancer. Compared with gene mutations, aberrant epigenetic changes occur more frequently, and cellular epigenome is more susceptible to change by environmental factors. Excess cancer risks are positively associated with exposure to occupational and environmental chemical carcinogens, including those from gasoline combustion exhausted in vehicles. Of note, previous studies proposed particulate matter index (PMI) as a measure for gasoline sooting tendency, and showed that, compared with the other molecules in gasoline, 1,2,4-Trimethylbenzene, 2-methylnaphthalene and toluene significantly contribute to PMI of the gasoline blends. Mechanistically, both epigenome and genome are important in carcinogenicity, and the genotoxicity of chemical agents has been thoroughly studied. However, less effort has been put into studying the epigenotoxicity. Moreover, as the blending of ethanol into gasoline substitutes for carcinogens, like benzene, toluene, xylene, butadiene, and polycyclic aromatic hydrocarbons, etc., a reduction of secondary aromatics has been achieved in the atmosphere. This may lead to diminished cancer initiation and progression through altered cellular epigenetic landscape. The present review summarizes the most important findings in the literature on the association between exposures to carcinogens from gasoline combustion, cancer epigenetics and the potential epigenetic impacts of biofuels.

Analysis of Postdeployment Serum Samples Identifies Potential Biomarkers of Exposure to Burn Pits and Other Environmental Hazards

OBJECTIVE

The potential health risks of deployment to sites with open burn pits remain poorly understood, in part, because personal exposure monitoring was not performed. Here, we investigated whether postdeployment serum samples contain biomarkers associated with exposure to burn pits.

METHODS

A total of 237 biomarkers were measured in 800 serum samples from deployed and never-deployed subjects. We used a regression model and a supervised vector machine to identify serum biomarkers with significant associations with exposures and deployment.

RESULTS

We identified 101 serum biomarkers associated with polycyclic aromatic hydrocarbons, dioxins or furans, and 54 biomarkers associated with deployment. Twenty-six of these biomarkers were shared in common by the exposure and deployment groups.

CONCLUSIONS

We identify a potential signature of exposure to open burn pits, and provide a framework for using postexposure sera to identify exposures when contemporaneous monitoring was inadequate.

microRNAs expression in relation to particulate matter exposure: A systematic review

MicroRNAs (miRNAs) are a class of small, non-coding RNAs with a post-transcriptional regulatory function on gene expression and cell processes, including proliferation, apoptosis and differentiation. In recent decades, miRNAs have attracted increasing interest to explore the role of epigenetics in response to air pollution. Air pollution, which always contains kinds of particulate matters, are able to reach respiratory tract and blood circulation and then causing epigenetics changes. In addition, extensive studies have illustrated that miRNAs serve as a bridge between particulate matter exposure and health-related effects, like inflammatory cytokines, blood pressure, vascular condition and lung function. The purpose of this review is to summarize the present knowledge about the expression of miRNAs in response to particulate matter exposure. Epidemiological and experimental studies were reviewed in two parts according to the size and source of particles. In this review, we also discussed various functions of the altered miRNAs and predicted potential biological mechanism participated in particulate matter-induced health effects. More rigorous studies are worth conducting to understand contribution of particulate matter on miRNAs alteration and the etiology between environmental exposure and disease development.

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.

MicroRNAs as biomarkers of harmful environmental and occupational exposures: a systematic review

Environmental exposure is a growing public health burden associated with several negative health effects. An estimated 4.2 million deaths occur each year from ambient air pollution alone. Biomarkers that reflect specific exposures have the potential to measure the real integrated internal dose from all routes of complex environmental exposure. MicroRNAs (miRNAs), small non-coding RNAs that regulate gene expression, have been studied as biomarkers in various diseases and have also shown potential as environmental exposure biomarkers. Here, we review the available human epidemiological and experimental evidence of miRNA expression changes in response to specific environmental exposures including airborne particulate matter. In doing so, we establish that miRNA exposure biomarker development remains in its infancy and future studies will need to carefully consider biological and analytical 'design rules' in order to facilitate clinical translation.

Expression levels of circulating microRNAs-126, -155, and -145 in Mexican women exposed to polycyclic aromatic hydrocarbons through biomass fuel use

Human exposure to polycyclic aromatic hydrocarbons (PAHs) has been considered a risk determinant for the development of cardiovascular diseases (CVD). Therefore, the aim of this study was to assess expression levels of vascular-related miRNAs, miR-126, miR-155, and miR-145, in plasma from women (aged 19-81 years) exposed (n = 100) and non-exposed (n = 20) to PAHs via biomass combustion smoke.1-hydroxypyrene (1-OHP) was determined in urine as a biomarker of exposure to PAHs using high-resolution liquid chromatography. Plasma expression levels of proposed miRNAs were determined by quantitative real-time PCR. Additionally, traditional risk factors (age, blood pressure, serum lipid profile, blood glucose, and among others) associated with CVD were evaluated. Urinary 1-OHP concentrations and plasma expression levels of miR-126 and miR-155 were significantly higher (P < 0.05) in women using wood as a fuel source in their homes (indoor) compared to women from the reference group (non-exposed to biomass smoke). Besides, multivariate linear regression analyses revealed that miR-126[β = 0.61; 95% confidence interval (0.32-0.90)] and miR-155 [β = 0.45; 95% confidence interval (0.13-0.84)] expression levels were significantly associated with urinary 1-OHP concentrations after being adjusted by traditional risk factors (P < 0.05). In contrast, no significant relationship was found between miR-145 and urinary 1-OHP levels. Furthermore, miRNAs assessed in this investigation are associated with CVD events. Consequently, actions to reduce exposure to PAHs in the evaluated population are warranted. Environ. Mol. Mutagen. 60:546-558, 2019. © 2019 Wiley Periodicals, Inc.

Co-exposure to metals and polycyclic aromatic hydrocarbons, microRNA expression, and early health damage in coke oven workers

BACKGROUND

All humans are now co-exposed to multiple toxic chemicals, among which metals and polycyclic aromatic hydrocarbons (PAHs) are of special concern as they are often present at high levels in various human environments. They can also induce similar early health damage, such as genetic damage, oxidative stress, and heart rate variability (HRV). Exposure to metals, PAHs, and their combined pollutants can alter microRNA (miRNA) expression patterns.

OBJECTIVES

To explore the associations of metal-PAH co-exposure with miRNA expression, and of the associated miRNAs with early health damage.

METHODS

We enrolled 360 healthy male coke oven workers and quantified their exposure levels of metals and PAHs by urinary metals, urinary monohydroxy-PAHs (OH-PAHs), and plasma benzo[a]pyrene-r-7,t-8,t-9,c-10-tetrahydotetrol-albumin (BPDE-Alb) adducts, respectively. We selected and measured ten miRNAs: let-7b-5p, miR-126-3p, miR-142-5p, miR-150-5p, miR-16-5p, miR-24-3p, miR-27a-3p, miR-28-5p, miR-320b, and miR-451a. For miRNAs influenced by the effect modification of metals or PAHs and/or metal-PAH interactions, we further evaluated their associations with biomarkers for genetic damage, oxidative stress, and HRV.

RESULTS

After adjusting for PAHs and other metals, miRNA expression was found to be negatively associated with aluminum, antimony, lead, and titanium, and positively associated with molybdenum and tin (p < 0.05). Antimony showed modifying effects on the PAH-miRNA associations, while OH-PAHs and BPDE-Alb adducts modified the associations of metals with miRNAs (p for modifying effect < 0.05). Furthermore, miRNA expression was influenced by the antagonistic interactions between antimony and OH-PAHs, and by the synergistical interactions between metals and BPDE-Alb adducts (p_interaction < 0.05). Let-7b-5p, miR-126-3p, miR-16-5p, and miR-320b were additionally found to be associated with increased genetic damage in the present study [false discovery rate (FDR)-adjusted p < 0.05].

CONCLUSIONS

Associations of metal-PAH co-exposure with miRNA expression, and of associated miRNAs with early health damage, suggested potential mechanistic connections between the complex metal-PAH interactions and their deleterious effects that are worthy of further investigation.

Small non-coding RNA profiling in human biofluids and surrogate tissues from healthy individuals: description of the diverse and most represented species

The role of non-coding RNAs in different biological processes and diseases is continuously expanding. Next-generation sequencing together with the parallel improvement of bioinformatics analyses allows the accurate detection and quantification of an increasing number of RNA species. With the aim of exploring new potential biomarkers for disease classification, a clear overview of the expression levels of common/unique small RNA species among different biospecimens is necessary. However, except for miRNAs in plasma, there are no substantial indications about the pattern of expression of various small RNAs in multiple specimens among healthy humans. By analysing small RNA-sequencing data from 243 samples, we have identified and compared the most abundantly and uniformly expressed miRNAs and non-miRNA species of comparable size with the library preparation in four different specimens (plasma exosomes, stool, urine, and cervical scrapes). Eleven miRNAs were commonly detected among all different specimens while 231 miRNAs were globally unique across them. Classification analysis using these miRNAs provided an accuracy of 99.6% to recognize the sample types. piRNAs and tRNAs were the most represented non-miRNA small RNAs detected in all specimen types that were analysed, particularly in urine samples. With the present data, the most uniformly expressed small RNAs in each sample type were also identified. A signature of small RNAs for each specimen could represent a reference gene set in validation studies by RT-qPCR. Overall, the data reported hereby provide an insight of the constitution of the human miRNome and of other small non-coding RNAs in various specimens of healthy individuals.

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.