The dioxin-like pollutant PCB 126 (3,3',4,4',5-pentachlorobiphenyl) affects risk factors for cardiovascular disease in female rats

Associations of polychlorinated biphenyls exposure, lifestyle, and genetic susceptibility with dyslipidemias: Evidence from a general Chinese population

Polychlorinated biphenyls (PCBs) are endocrine-disrupting chemicals that have been associated with various adverse health conditions. Herein we explored the associations of PCBs with dyslipidemia and further assessed the modification effect of genetic susceptibility and lifestyle factors. Six serum PCBs (PCB-28, 101, 118, 138, 153, 180) were determined in 3845 participants from the Wuhan-Zhuhai cohort. Dyslipidemia, including hyper-total cholesterol (HyperTC), hyper-triglyceride (HyperTG), hyper-low density lipoprotein cholesterol (HyperLDL-C), and hypo-high density lipoprotein cholesterol (HypoHDL-C) were determined, and lipid-specific polygenic risk scores (PRS) and healthy lifestyle score were constructed. We found that all six PCB congeners were positively associated with the prevalence of dyslipidemias, and ΣPCB level was associated with HyperTC, HyperTG, and HyperLDL-C in dose-response manners. Compared with the lowest tertiles of ΣPCB, the odds ratios (95% confidence intervals) in the highest tertiles were 1.490 (1.258, 1.765) for HyperTC, 1.957 (1.623, 2.365) for HyperTG, and 1.569 (1.316, 1.873) for HyperLDL-C, respectively. Compared with those with low ΣPCB, healthy lifestyle, and low genetic risk, participants with high ΣPCB, unfavorable lifestyle, and high genetic risk had the highest odds of HyperTC, HyperTG, and HyperLDL-C. Our study provided evidence that high PCB exposure exacerbated the association of genetic risk and unhealthy lifestyle with dyslipidemia.

Photodegradation of polychlorinated biphenyls in water/nitrogen-doped silica and air/nitrogen-doped silica systems: Kinetics, mechanism and quantitative structure activity relationship (QSAR) analysis

Developing efficient and low-cost photocatalytic materials is essential for removing polychlorinated biphenyls (PCBs). In this work, the photodegradation process of fourteen representative polychlorinated biphenyls (PCBs) in both water/nitrogen-doped SiO2 (N-SiO2) and air/N-SiO2 systems was studied. The photodegradation kinetics of PCBs is consistent with the pseudo-first-order kinetic equation. The variation in the degradation effects of different PCBs in the two systems is primarily related to the position of the Cl substituent and the effective absorption wavelength range of PCBs. A total of fourteen intermediates for 4'-Dichlorobiphenyl (PCB-15), 2,2',4,4',6,6'-Hexachlorobiphenyl (PCB-155), and 2,2',3,3',4,4',5,5',6,6'-Decachlorobiphenyl (PCB-209) generated from four reaction pathways were identified based on both mass spectrometry analysis and theoretical calculations. Using the values of lnk (k denotes pseudo-first-order kinetic constants) for the 11 PCBs in the training set and the calculated molecular and structural parameters, quantitative structure-activity relationship (QSAR) models for the two systems were constructed by using multiple linear regression (MLR) method to better understand the factors affecting the photodegradation rate of PCBs. The QSAR equations were obtained with Cl atom substitution at position 3 (N3) as the main parameter, which were lnk = -1.98 - 0.19 N3 for the water/N-SiO2 system and lnk = -1.56 - 0.34 N3 for the air/N-SiO2 system, with the correlation coefficient (R2) of 0.66 and 0.73, leave-one-out cross-validation (Q2LOO) of 0.51 and 0.59, respectively, and bootstrapping validation coefficients (Q2BOOT) values of both 0.74, confirming that the models were well fitted and showed high robustness and prediction ability. This study provides valuable insights into photocatalytic degradation studies of PCBs.

Telomere length as a modifier in the relationship between phthalate metabolites exposure and glucose homeostasis

Given the rising concern over the potential impact of environmental factors on metabolic heath, we conducted a cross-sectional analysis among 645 adults aged 20 and older in the National Health and Nutrition Examination Survey (NHANES), examining the association between nine phthalate metabolites (Mono-n-butyl phthalate (MBP), Mono-ethyl phthalate (MEP), Mono-(2-ethyl)-hexyl phthalate (MEHP), Mono-benzyl phthalate (MBzP), Mono-n-methyl phthalate (MnMP), Mono-(3-carboxy propyl) phthalate (MCPP), Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), Mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), Mono-isobutyl phthalate (MiBP)) and six glucose homeostasis indices (fasting glucose, fasting insulin, hemoglobin A1C (HbA1C), homeostatic model assessment of insulin resistance (HOMA-IR), single Point Insulin Sensitivity Estimator (SPISE), and HOMA-β). Latent Class Analysis identified three phthalate metabolites exposure patterns: high MEP-low MEOHP (n = 282), high MBzP-low MEHHP (n = 214), and high MEHHP, MEOHP (n = 149). The high MBzP-low MEHHP and high MEHHP, MEOHP, versus the high MEP-low MEOHP, exposure groups showed significantly higher levels of fasting insulin (β = 0.126, 95% CI: 0.023-0.228), SPISE (β = 0.091, 95% CI: 0.018-0.164), and HOMA-IR (β = 0.091, 95% CI: 0.018-0.164). In the shorter telomere length group, high MEHHP, MEOHP exposure showed an increase in SPISE levels (β = 0.153, 95% CI: 0.037-0.269), while in the overweight/obese subgroup, high MEHHP, MEOHP exposure was significantly positively associated with HOMA-IR (β = 0.392, 95% CI: 0.150-0.735). Bayesian kernel machine regression analyses showed positive associations between higher combined phthalate exposure and increased glucose homeostasis indices (fasting glucose, HbA1C, fasting insulin, SPISE, and HOMA-IR). The quantile of g-calculation analysis also supported the positive associations with HbA1C, HOMA-IR, and fasting insulin. Our findings indicate that phthalate exposure was positively associated with glucose homeostasis indices, which strengthen the call for proactive measures to reduce phthalate exposure and mitigate potential risks to glucose metabolism.

A review of food contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin and its toxicity associated with metabolic disorders

Dioxins are a group of chemicals not only regarded as highly toxic trace environmental contaminants, but also considered typical contaminants in food. Dioxins spread across the ecosystem after factory manufacture, contaminate the soil and vegetation before either directly or indirectly entering the food chain through meat products, dairy products, and aquatic products. The compound in question poses a challenge for metabolic processes within the human body, due to its intricate mechanism for inducing diseases. Therefore, it presents a significant risk and is largely undisclosed. Dioxins are mainly exposed to humans by water, food, and air, as well as inducing organ failure and metabolic disorders through but not limited to the activation of aryl hydrocarbon receptors (AhR). As a notorious compound in the family of dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exhibits long-term toxic effects on diverse organs, which induces continuous metabolic disorders. This review discussed the mechanisms of TCDD-associated metabolic syndrome. The expression of the cytochrome P450 subfamily transfers TCDD into liver, promotes its accumulation in fat tissue, and affects cholesterol metabolism. This process also alters the glucose tolerance of the human organism, disrupting glucose metabolism. It can also elicit cardiovascular pathogenesis, exacerbate liver fibrosis and neuronal death. The long-term metabolic impact of this effect is found to be sex-related. This review summarized the toxicity of TCDD on the human metabolism system and discussed the plausible correlation between TCDD and five metabolic disorders, which helped offer novel insights for future research and therapeutic interventions for these ailments.

Risk of cardiovascular diseases following residential exposure to airborne polychlorinated biphenyls: A register-based cohort study

BACKGROUND

Indoor air in buildings constructed with materials containing polychlorinated biphenyls (PCBs) may be contaminated with especially lower-chlorinated PCBs. So far, the cardiovascular consequences of living with such contamination are unknown.

OBJECTIVES

To determine the risk of cardiovascular disease (CVD) following residential exposure to predominantly lower-chlorinated PCBs in indoor air.

METHODS

The Health Effects of PCBs in Indoor Air (HESPAIR) cohort is register-based with 51 921 residents of two residential areas near Copenhagen: Farum Midtpunkt and Brøndby Strand Parkerne. Here, indoor air was contaminated with PCB in one third of the apartments due to construction with materials containing PCB. Individual PCB exposure was estimated based on register-based information on relocation dates and indoor air PCB measurements in subsets of the apartments. Information on CVD was retrieved from the Danish National Patient Register for the follow-up period of 1977-2018. We estimated adjusted hazard ratios using Cox regression with time-varying exposure.

RESULTS

Cumulative residential exposure to airborne PCB was not associated with a higher overall risk for CVD (HR for highly exposed (≥3300 ng/m³ PCB × year): 1.02, 95% CI 0.94-1.10). This was also the case for most of the specific cardiovascular diseases, apart from acute myocardial infarction where a higher risk was observed for residents exposed to ≥3300 ng/m³ PCB × year compared to the reference group (HR 1.17, 95% CI 1.00-1.35). However, no exposure-response relationship was apparent and additional adjustment for education attenuated the risk estimate.

DISCUSSION

In this, to our knowledge, first study ever to examine the risk of CVD following residential exposure to PCBs in indoor air, we observed limited support for cardiovascular effects of living in PCB-contaminated indoor air. Considering the prevalence of exposure to airborne PCBs and lack of literature on their potential health effects, these findings need to be corroborated in other studies.

Reduced Transcriptome Analysis of Zebrafish Embryos Prioritizes Environmental Compounds with Adverse Cardiovascular Activities

Cardiovascular diseases are the leading cause of premature death in humans and remain a global public health challenge. While age, sex, family history, and false nutrition make a contribution, our understanding of compounds acting as cardiovascular disruptors is far from complete. Here, we aim to identify cardiovascular disruptors via a reduced transcriptome atlas (RTA) approach, which integrates large-scale transcriptome data sets of zebrafish and compiles a specific gene panel related to cardiovascular diseases. Among 767 gene expression profiles covering 81 environmental compounds, 11 priority compounds are identified with the greatest effects on the cardiovascular system at the transcriptional level. Among them, metals (AgNO₃, Ag nanoparticles, arsenic) and pesticides/biocides (linuron, methylparaben, triclosan, and trimethylchlorotin) are identified with the most significant effects. Distinct transcriptional signatures are further identified by the percentage values, indicating that different physiological endpoints exist among prioritized compounds. In addition, cardiovascular dysregulations are experimentally confirmed for the prioritized compounds via alterations of cardiovascular physiology and lipid profiles of zebrafish. The accuracy rate of experimental verification reaches up to 62.9%. The web-based RTA analysis tool, Cardionet, for rapid cardiovascular disruptor discovery was further provided at http://www.envh.sjtu.edu.cn/cardionet.jsp. Our integrative approach yields an efficient platform to discover novel cardiovascular-disrupting chemicals in the environment.

Long-term effects of defoliant exposure on brain atrophy progression in humans

As the most toxic dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin is classified as a group 1 human carcinogen. We investigated the long-term effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure on the progression of brain atrophy in humans. We retrospectively selected 546 patients exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (exposed group) and 1353 patients not exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (control group). The patients in both groups underwent brain T1-weighted magnetic resonance imaging (MRI) twice. We divided the patients into two propensity score-matched groups, analyzed voxel-wise whole brain atrophy in the MRI images of each patient, and compared the progression of brain atrophy between the two groups. The exposed group showed significant brain atrophy progression in the bilateral frontal and temporal lobes, compared with the control group. The ventrolateral prefrontal area in the frontal lobe and whole temporal lobe were the main atrophic regions in the exposed group, compared with the control group. The neurotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin can damage the brain, even in patients exposed to it over 40 years ago. Humans exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin should thus be evaluated for progression of brain atrophy.

Serum levels of polychlorinated biphenyls and stroke risk among Chinese: a hospital-based case-control study

Previous studies have revealed the serious human health risk effects of organic pollutants-polychlorinated biphenyls (PCBs). However, the roles of circulating PCBs on stroke risk have not been elucidated. The purpose of this study was to examine whether serum PCBs could increase the risk for stroke among Chinese participants. A total of 241 patients with stroke and age- (5-year interval) and gender-matched controls were recruited in Tianjin, China. Concentrations of 17 PCB congeners were measured by using high-resolution gas chromatography with mass spectrometric detection. Conditional logistic regression models were applied to assess the odds ratio (OR) and 95% confidential interval (CI). Significant positive associations were observed between serum total PCBs and dioxin-like PCBs and the risk for stroke (all p trends < 0.05), and the adjusted ORs for the highest tertile (T3) of serum concentration compared with the lowest tertile (T1) were 1.704 (1.073, 2.506) and 1.846 (1.156, 2.949). However, no significant association was found for non-dioxin-like PCBs (OR for T3 vs. T1: 1.388, 95%CIs: 0.850, 2.266; p trend: 0.118). Stratified analysis by stroke subtypes (ischemic or hemorrhagic strokes) showed no significant heterogeneity (OR for T3 vs. T1: 1.644 vs. 1.824; p for interaction: 0.458). The results suggest detrimental roles of PCBs, mainly dioxin-like PCBs, in stroke risk, irrespective of stroke subtypes. Further well-designed prospective studies with larger sample size are invited to confirm these associations.

Key Characteristics of Cardiovascular Toxicants

BACKGROUND

The concept of chemical agents having properties that confer potential hazard called key characteristics (KCs) was first developed to identify carcinogenic hazards. Identification of KCs of cardiovascular (CV) toxicants could facilitate the systematic assessment of CV hazards and understanding of assay and data gaps associated with current approaches.

OBJECTIVES

We sought to develop a consensus-based synthesis of scientific evidence on the KCs of chemical and nonchemical agents known to cause CV toxicity along with methods to measure them.

METHODS

An expert working group was convened to discuss mechanisms associated with CV toxicity.

RESULTS

The group identified 12 KCs of CV toxicants, defined as exogenous agents that adversely interfere with function of the CV system. The KCs were organized into those primarily affecting cardiac tissue (numbers 1-4 below), the vascular system (5-7), or both (8-12), as follows: 1) impairs regulation of cardiac excitability, 2) impairs cardiac contractility and relaxation, 3) induces cardiomyocyte injury and death, 4) induces proliferation of valve stroma, 5) impacts endothelial and vascular function, 6) alters hemostasis, 7) causes dyslipidemia, 8) impairs mitochondrial function, 9) modifies autonomic nervous system activity, 10) induces oxidative stress, 11) causes inflammation, and 12) alters hormone signaling.

DISCUSSION

These 12 KCs can be used to help identify pharmaceuticals and environmental pollutants as CV toxicants, as well as to better understand the mechanistic underpinnings of their toxicity. For example, evidence exists that fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] air pollution, arsenic, anthracycline drugs, and other exogenous chemicals possess one or more of the described KCs. In conclusion, the KCs could be used to identify potential CV toxicants and to define a set of test methods to evaluate CV toxicity in a more comprehensive and standardized manner than current approaches. https://doi.org/10.1289/EHP9321.

AHR canonical pathway: in vivo findings to support novel antihypertensive strategies

Essential hypertension (HTN) is a disease where genetic and environmental factors interact to produce a high prevalent set of almost indistinguishable phenotypes. The weak definition of what is under the umbrella of HTN is a consequence of the lack of knowledge on the players involved in environment-gene interaction and their impact on blood pressure (BP) and mechanisms. The disclosure of these mechanisms that sense and (mal)adapt to toxic-environmental stimuli might at least determine some phenotypes of essential HTN and will have important therapeutic implications. In the present manuscript, we looked closer to the environmental sensor aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor involved in cardiovascular physiology, but better known by its involvement in biotransformation of xenobiotics through its canonical pathway. This review aims to disclose the contribution of the AHR-canonical pathway to HTN. For better mirror the complexity of the mechanisms involved in BP regulation, we privileged evidence from in vivo studies. Here we ascertained the level of available evidence and a comprehensive characterization of the AHR-related phenotype of HTN. We reviewed clinical and rodent studies on AHR-HTN genetic association and on AHR ligands and their impact on BP. We concluded that AHR is a druggable mechanistic linker of environmental exposure to HTN. We conclude that is worth to investigate the canonical pathway of AHR and the expression/polymorphisms of its related genes and/or other biomarkers (e.g. tryptophan-related ligands), in order to identify patients that may benefit from an AHR-centered antihypertensive treatment.

Co-exposure to PCB126 and PFOS increases biomarkers associated with cardiovascular disease risk and liver injury in mice

Polychlorinated biphenyl (PCB)126 and perfluorooctane sulfonic acid (PFOS) are halogenated organic pollutants of high concern. Exposure to these chemicals is ubiquitous, and can lead to potential synergistic adverse effects in individuals exposed to both classes of chemicals. The present study was designed to identify interactions between PCB126 and PFOS that might promote acute changes in inflammatory pathways associated with cardiovascular disease and liver injury. Male C57BL/6 mice were exposed to vehicle, PCB126, PFOS, or a mixture of both pollutants. Plasma and liver samples were collected at 48 h after exposure. Changes in the expression of hepatic genes involved in oxidative stress, inflammation, and atherosclerosis were investigated. Plasma and liver samples was analyzed using untargeted lipidomic method. Hepatic mRNA levels for Nqo1, Icam1, and PAI1 were significantly increased in the mixture-exposed mice. Plasma levels of PAI1, a marker of fibrosis and thrombosis, were also significantly elevated in the mixture-exposed group. Liver injury was observed only in the mixture-exposed mice. Lipidomic analysis revealed that co-exposure to the mixture enhanced hepatic lipid accumulation and elevated oxidized phospholipids levels. In summary, this study shows that acute co-exposure to PCB126 and PFOS in mice results in liver injury and increased cardiovascular disease risk.

Association between exposure to polychlorinated biphenyls and risk of hypertension: A systematic review and meta-analysis

Experimental and epidemiological studies have suggested an association between exposure to polychlorinated biphenyls (PCBs), ubiquitous environmental toxic compounds, and the risk of hypertension. We conducted a systematic review and meta-analysis of epidemiological studies of the association between PCB exposure and the risk of hypertension. Studies were identified by searching PubMed, Embase and Web of Science and by reviewing reference lists. Study-specific risk estimates comparing the highest versus lowest quantile of PCB distribution were combined using random-effects models. We identified 10 cross-sectional studies, 6 cohort studies, and 1 nested case-control study. A pooled excess risk of hypertension was found for total PCBs (OR 1.70, 95% CI 1.28-2.26), dioxin-like (DL)-PCBs (OR 1.46, 1.19-1.79), but not for non-dioxin like (NDL)-PCBs (OR 1.19, 0.81-1.73) comparing the highest with the lowest quartile of the distribution. According to a dose-response meta-analysis, a linear dose-effect relationship was found for total PCBs [OR 2.23 (95% CI: 1.59-3.14) for 1000 ng PCB/g lipid increase]. This positive association remained when stratifying the analyses by study design (cohort vs cross-sectional studies) and population (general population vs high exposed workers/residents). Among single PCB congeners, DL-PCB 105 and 118, and non-DL-PCB138 and 153 were related to hypertension. In conclusion, this meta-analysis suggests that exposure to PCBs, particularly to DL-PCBs, may be a risk factor for hypertension, independently of other risk factors.

Are Persistent Organic Pollutants Linked to Lipid Abnormalities, Atherosclerosis and Cardiovascular Disease? A Review

The term persistent organic pollutants (POPs) denotes chemicals with known or suspected adverse health effects in animals or humans and with chemical properties that make them accumulate in the environment, including animals or humans. Lipid-soluble POPs, like dioxins, polychlorinated biphenyls (PCBs) and organochlorine pesticides are transported by lipoproteins and accumulate in adipose tissue. High levels of these compounds in the circulation have been associated with elevated cholesterol and triglycerides in cross-sectional studies and with an increase in mainly low-density lipoprotein cholesterol in a longitudinal study. Also, non-lipid-soluble POPs, such as perfluoroalkyl substances (PFASs) compounds have been associated with increased total cholesterol levels. Carotid artery atherosclerosis has been related to elevated levels of mainly highly chlorinated PCBs and to highly fluorinated PFASs, but in this case only in women. Both cross-sectional and prospective studies have shown dioxins, PCBs, as well as PFASs to be linked to cardiovascular disease (CVD) and mortality. In conclusion, as highlighted in this review, several lines of evidence support the view that POPs of different chemical classes could be linked to lipid abnormalities, carotid atherosclerosis and overt CVD like myocardial infarction and stroke.

Exposure to 2,3,3',4,4',5-hexachlorobiphenyl promotes nonalcoholic fatty liver disease development in C57BL/6 mice

Previous in vitro studies have indicated that 2,3,3',4,4',5-hexachlorobiphenyl (PCB 156) may be a new contributor to metabolic disruption and may further cause the occurrence of nonalcoholic fatty liver disease (NAFLD). However, no study has clarified the specific contributions of PCB 156 to NAFLD progression by constructing an in vivo model. Herein, we evaluated the effects of PCB 156 treatment (55 mg/kg, i.p.) on the livers of C57BL/6 mice fed a control diet (CD) or a high-fat diet (HFD). The results showed that PCB 156 administration increased intra-abdominal fat mass, hepatic lipid levels and dyslipidemia in the CD-fed group and aggravated NAFLD in HFD-fed group. By using transcriptomics studies and biological methods, we found that the genes expression involved in lipid metabolism pathways, such as lipogenesis, lipid accumulation and lipid β-oxidation, was greatly altered in liver tissues exposed to PCB 156. In addition, the cytochrome P450 pathway, peroxisome proliferator-activated receptors (PPARs) and the glutathione metabolism pathway were significantly activated following exposure to PCB 156. Furthermore, PCB 156 exposure increased serum transaminase levels and lipid peroxidation, and the redox-related genes were significantly dysregulated in liver tissue. In conclusion, our data suggested that PCB 156 could promote NAFLD development by altering the expression of genes related to lipid metabolism and inducing oxidative stress.

Serum concentrations of persistent organic pollutants and the metabolic syndrome in Akwesasne Mohawks, a Native American community

The metabolic syndrome (MetS) is a group of diseases that tend to occur together, including diabetes, hypertension, central obesity, cardiovascular disease and hyperlipidemia. Exposure to persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) has been associated with increased risk of development of several of the components of the MetS. The goal of this study is to determine whether the associations with POPs are identical for each of the components and for the MetS. The subject population was 601 Native Americans (Akwesasne Mohawks) ages 18 to 84 who answered a questionnaire, were measured for height and weight and provided blood samples for clinical chemistries (serum lipids and fasting glucose) and analysis of 101 PCB congeners and three OCPs [dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB) and mirex]. Associations between concentrations of total PCBs and pesticides, as well as various PCB congener groups with each of the different components of the MetS were determine so as to ask whether there were similar risk factors for all components of the MetS. After adjustment for other contaminants, diabetes and hypertension were strongly associated with lower chlorinated and mono-ortho PCBs, but not other PCB groups or pesticides. Obesity was most closely associated with highly chlorinated PCBs and was negatively associated with mirex. High serum lipids were most strongly associated with higher chlorinated PCBs and PCBs with multiple ortho-substituted chlorines, as well as total pesticides, DDE and HCB. Cardiovascular disease was not closely associated with levels of any of the measured POPs. While exposure to POPs is associated with increased risk of most of the various diseases comprising the MetS, the specific contaminants associated with risk of the component diseases are not the same.

Exposure to dietary polychlorinated biphenyls and dioxins, and its relationship with subclinical coronary atherosclerosis: The Aragon Workers' Health Study

BACKGROUND

Experimental evidence has revealed that exposure to polychlorinated biphenyls (PCBs) and dioxins directly impairs endothelial function and induces atherosclerosis progression. In the general population, despite a small number of recent studies finding a link between PCBs, and stroke and myocardial infraction, the association with early coronary atherosclerosis has not been examined yet.

OBJECTIVE

To examine whether dietary exposure to PCBs and dioxins is associated with subclinical coronary atherosclerosis in a middle-aged men.

DESIGN

Cross-sectional analysis comprising 1844 men in their 50 s and free of cardiovascular disease, who participated in the Aragon Workers' Health Study (AWHS). Individual dietary exposures to PCBs and dioxins were estimated by the contaminant's concentration in food coupled with the corresponding consumption and then participants were classified into quartiles of consumption. Coronary artery calcium score (CACS) was assessed by computerized tomography. We conducted ordered logistic regressions to estimate the odds ratio (OR) and 95% confidence intervals (CIs) for progression to the categories of more coronary artery calcium, adjusting for potential confounders.

RESULTS

Among the participants, coronary calcium was not shown in 60.1% (n = 1108), 29.8% had a CACS > 0 and <100 (n = 550), and the remaining 10.1% (n = 186) had a CACS ≥ 100. Compared with those in the first quartile of PCBs exposure, those in the fourth one had an increased odds for having coronary calcium (OR 2.02, 95% CI [1.18, 3.47], p trend 0.019) and for having progressed to categories of more intense calcification (OR 2.03, 95% CI [1.21, 3.40], p trend 0.012). However, no association was found between dietary dioxins exposure and prevalent coronary artery calcium.

CONCLUSIONS

In this general male population, dietary exposure to PCBs, but not to dioxins, was associated with a higher prevalence of coronary calcium and to more intense subclinical coronary atherosclerosis. PCBs exposure seems to increase the risk of coronary disease in men from the very early stages.

Cardiovascular and cancer mortality in relation to dietary polychlorinated biphenyls and marine polyunsaturated fatty acids: a nutritional-toxicological aspect of fish consumption

BACKGROUND

Co-exposure to environmental contaminants present in fish could mitigate the beneficial effects of fish consumption and possibly explain the lack of association observed for mortality in some geographical regions.

OBJECTIVE

To assess the independent associations of dietary exposure to polychlorinated biphenyls (PCBs) and long-chain omega-3 fish fatty acids intake with cardiovascular and cancer mortality.

METHODS

We used the prospective population-based Swedish Mammography Cohort and the Cohort of Swedish Men comprising 32 952 women and 36 545 men, free from cancer, cardiovascular disease and diabetes at baseline in 1998. Validated estimates of dietary PCBs and long-chain omega-3 fish fatty acids [i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] intake were obtained via a food frequency questionnaire at baseline. Information on death was ascertained through register linkage.

RESULTS

During a mean follow-up of 15.5 years, we ascertained 16 776 deaths. We observed for cardiovascular mortality, comparing extreme quintiles in multivariable models mutually adjusted for PCBs and EPA-DHA, dose-dependent associations for dietary PCB exposure, hazard ratio (HR) 1.31 (CI 95%: 1.08 to 1.57; P-trend 0.005) and for dietary EPA-DHA intake, HR 0.79 (CI 95%: 0.66 to 0.95; P-trend 0.041). For cancer mortality, no clear associations were discerned.

CONCLUSION

The beneficial effect of fish consumption on the cardiovascular system seems compromised by co-exposure to PCBs - one likely explanation for the inconsistent associations observed between fish consumption and mortality.

Skeletal toxicity resulting from exposure of growing male rats to coplanar PCB 126 is associated with disruption of calcium homeostasis and the GH-IGF-1 axis and direct effects on bone formation

Skeletal toxicity has been reported following exposure to polychlorinated biphenyl (PCB) mixtures. However, molecular mechanisms remain poorly understood. We exposed groups of male 4-5-week-old Sprague-Dawley rats to 3,3', 4, 4', 5-pentachlorobiphenyl (PCB 126), a dioxin-like coplanar PCB congener by a single i.p. injection of 5 µmol/kg in soy oil vehicle or vehicle alone. After 4 weeks, rats were euthanized. PCB exposure resulted in hypocalcemia (P < 0.05) and significant increases in serum PTH without changes in serum phosphorous. Hyperparathyroidism was accompanied by increased expression of mRNAs of vitamin D3 metabolizing cytochrome P450 enzymes CYP27B1 and CYP24 in the kidney (P < 0.05). PCB exposure also reduced body weight, serum IGF-1, and hepatic expression of mRNAs encoding the male-specific GH-pattern-regulated CYP2C11 and CYP3A2 relative to controls (P < 0.05). PCB exposure reduced long bone length, diameter, and surface area, but increased trabecular thickness and volume (P < 0.05). Serum osteocalcin (P < 0.05), a marker and a regulator of bone formation, was reduced, but PCB exposure had no effect on the bone resorption marker RatLaps. Exposure of human intestinal Caco-2 cells to 10-100 nM PCB 126 in the presence of vitamin D3 resulted in inhibition of mRNAs for the calcium transporters TRPV6 and PMCA1b (P < 0.05). In addition, PCB 126 suppressed osteoblastogenesis in primary bone marrow mesenchymal stem cell cultures which was blunted by the AhR antagonist CH-223191. These data provide novel evidence that skeletal toxicity after exposure to PCB 126 is a result of disruption of calcium homeostasis and the GH-IGF-1 axis, and involves direct AhR-mediated effects on bone formation.

Association of Exposure to Persistent Organic Pollutants With Mortality Risk: An Analysis of Data From the Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS) Study

IMPORTANCE

It has been suggested that persistent organic pollutants (POPs) are harmful to human health.

OBJECTIVE

To investigate if POP levels in plasma are associated with future mortality.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study using data from the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, collected between May 2001 and June 2004 when participants reached age 70 years. Participants were followed up for 5 years after the first examination. Mortality was tracked from age 70 to 80 years. Data analysis was conducted in January and February 2018.

EXPOSURES

Eighteen POPs identified by the Stockholm Convention, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and a brominated flame retardant, were measured in plasma levels by gas chromatography-mass spectrometry.

MAIN OUTCOMES AND MEASURES

All-cause mortality.

RESULTS

The study sample initially included 992 individuals (497 [50.1%] men) aged 70 years, who were examined between 2001 and 2004. At the second examination 5 years later, 814 individuals (82.1%; 412 [50.7%] women) completed follow-up. During a follow-up period of 10.0 years, 158 deaths occurred. When updated information on POP levels at ages 70 and 75 years was associated with all-cause mortality using Cox proportional hazard analyses, a significant association was found between hexa-chloro- through octa-chloro-substituted (highly chlorinated) PCBs and all-cause mortality (except PCB 194). The most significant association was observed for PCB 206 (hazard ratio [HR] for 1-SD higher natural log-transformed circulating PCB 206 levels, 1.55; 95% CI, 1.26-1.91; P < .001). Following adjustment for hypertension, diabetes, smoking, body mass index, and cardiovascular disease at baseline, most associations were no longer statistically significant, but PCBs 206, 189, 170, and 209 were still significantly associated with all-cause mortality (PCB 206: adjusted HR, 1.47; 95% CI, 1.19-1.81; PCB 189: adjusted HR, 1.29; 95% CI, 1.08-1.55; PCB 170: adjusted HR, 1.24; 95% CI, 1.02-1.52; PCB 209: adjusted HR, 1.29; 95% CI, 1.04-1.60). In a secondary analysis, these associations were mainly because of death from cardiovascular diseases rather than noncardiovascular diseases. Three organochlorine pesticides, including dichlorodiphenyldichloroethylene, and the brominated flame retardant diphenyl ether 47 were also evaluated but did not show any significant associations with all-cause mortality.

CONCLUSIONS AND RELEVANCE

Higher levels of highly chlorinated PCBs were associated with an increased mortality risk, especially from cardiovascular diseases. These results suggest that public health actions should be undertaken to minimize exposure to highly chlorinated PCBs.

Prenatal exposure to PCBs in Cyp1a2 knock-out mice interferes with F1 fertility, impairs long-term potentiation, reduces acoustic startle and impairs conditioned freezing contextual memory with minimal transgenerational effects

Polychlorinated biphenyls (PCBs) are toxic environmental pollutants. Humans are exposed to PCB mixtures via contaminated food or water. PCB exposure causes adverse effects in adults and after exposure in utero. PCB toxicity depends on the congener mixture and CYP1A2 gene activity. For coplanar PCBs, toxicity depends on ligand affinity for the aryl hydrocarbon receptor (AHR). Previously, we found that perinatal exposure of mice to a three-coplanar/five-noncoplanar PCB mixture induced deficits in novel object recognition and trial failures in the Morris water maze in Cyp1a2^-/- ::Ahr^b1 C57BL6/J mice compared with wild-type mice (Ahr^b1  = high AHR affinity). Here we exposed gravid Cyp1a2^-/- ::Ahr^b1 mice to a PCB mixture on embryonic day 10.5 by gavage and examined the F₁ and F₃ offspring (not F₂ ). PCB-exposed F₁ mice exhibited increased open-field central time, reduced acoustic startle, greater conditioned contextual freezing and reduced CA1 hippocampal long-term potentiation with no change in spatial learning or memory. F₁ mice also had inhibited growth, decreased heart rate and cardiac output, and impaired fertility. F₃ mice showed few effects. Gene expression changes were primarily in F₁ PCB males compared with wild-type males. There were minimal RNA and DNA methylation changes in the hippocampus from F₁ to F₃ with no clear relevance to the functional effects. F₀ PCB exposure during a period of rapid DNA de-/remethylation in a susceptible genotype produced clear F₁ effects with little evidence of transgenerational effects in the F₃ generation. While PCBs show clear developmental neurotoxicity, their effects do not persist across generations for effects assessed herein.

POPs' effect on cardiometabolic and inflammatory profile in a sample of women with obesity and hypertension

Persistent organic pollutants (POPs) are man-made compounds with metabolic disruption impact. We investigated the effect of POP exposure in the cardiometabolic and inflammatory profile in a population of women with obesity and hypertension. In 43 premenopausal women (22 treated vs. 21 nontreated) undergoing bariatric surgery, blood and adipose tissue samples (visceral (vAT) and abdominal subcutaneous (scAT)) were collected. Median concentrations of ∑HCH and ∑POPs in vAT were significantly higher in treated women. VAT ∑HCH and scAT ∑HCH and ∑POPs concentrations were positively correlated with systolic blood pressure in the non-treated group. Our findings suggest that exposure to POPs and its accumulation in vAT and circulating in plasma may be associated to a higher cardiovascular risk in women with obesity and hypertension, with or without antihypertensive treatment.

Polychlorinated biphenyls (PCBs) exposure and cardiovascular, endocrine and metabolic diseases: A population-based cohort study in a North Italian highly polluted area

BACKGROUND AND AIMS

Exposure to polychlorinated biphenyls (PCBs) has been linked to the onset of cardiovascular, endocrine, and metabolic diseases, but no conclusive evidence has been provided so far. A chemical factory produced PCBs from 1938 to 1984 in Brescia (North Italy) resulting in environmental contamination and human exposure. We aimed to evaluate the association between PCB serum levels and subsequent incidence of chronic diseases through a prospective cohort study design.

METHODS

Based on surveys conducted in Brescia province between 2001 and 2013, a cohort of 1331 subjects with at least one measure of PCB serum levels during the period was selected and followed longitudinally. Serum concentration of total PCBs was computed summing up the levels of 24 PCB congeners determined by gas chromatography. The data on incidence of hypertension, cardiovascular diseases, and endocrine and metabolic chronic diseases were retrieved from the Brescia Health Protection Agency database. Poisson regression models adjusted for age, level of education, BMI, cholesterol level, tobacco smoking and alcohol drinking were employed to calculate rate ratios (RRs).

RESULTS

1331 subjects were enrolled (45.7% males, mean age 50.6 years) contributing to 10,006 person-years of follow-up. A dose-response relationship was observed between PCB serum levels and the onset of hypertension (RR for 2nd and 3rd tertiles of serum PCB distribution: 2.07, 95% CI 1.18-3.63, and 2.41, 1.30-4.47, respectively). A possible, though not statistically significant, increase of the risk of cardiovascular disease was also found (RR for 2nd and 3rd tertiles of serum PCB distribution: 1.61, 0.72-3.64, and 1.96, 0.86-4.48, respectively). The results based on lipid-standardized PCBs were slightly attenuated. No association was found between PCB serum levels and occurrence of diabetes and endocrine disorders. Stratified analysis by body mass index showed an increased risk of hypertension in subjects at 2nd and 3rd tertile of serum PCB distribution in overweight/obese subjects only.

CONCLUSIONS

These results suggest that PCBs might play a role in the development of hypertension and possibly cardiovascular disease, though alternative explanations are to be considered too.

Fatty acids, polychlorinated dibenzo-p-dioxins and dibenzofurans, and dioxin-like polychlorinated biphenyls in paired muscle and skin from fish from the Bohai coast, China: Benefits and risks associated with fish consumption

Fish consumption benefits early cognitive development and cardiovascular health because of the n-3 long-chain polyunsaturated fatty acids in the fish, but toxic pollutants in fish, like dioxin-like polychlorinated biphenyls (dl-PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), may decrease or counteract these benefits. In this study, the fatty acids, dl-PCBs, and PCDD/Fs were analyzed in paired muscle and skin from 13 fish and one squid species from the Bohai coast, which have been influenced by serious dioxin pollution from the Bohai Rim Region. The total fatty acid concentrations in the muscle and skin were 2.6-87 and 3.6-156 mg/g wet weight (ww), respectively. The total polyunsaturated fatty acid concentrations were higher in skin than muscle for almost half of the species. The total PCDD/F and dl-PCB toxic equivalents in the muscle and skin were 0.055-0.68 and 0.0099-0.43 pg/g ww, respectively, and were up to five times higher in the muscle than in the skin for eight species. Few benefit-risk studies for fish consumption with and without skin have been performed, so benefit-risk quotients (BRQs) for eating only muscle, only skin, and eating both were calculated. To achieve the recommended 250 mg of EPA + DHA intake, eating only muscle, only skin, and eating both from seven species with BRQs < 1 would cause no significant risk. Removing skin before eating is not necessary for these species. Three fish species had BRQs < 1 for muscle only but BRQs > 1 for skin only. Removing skin before eating would be better for these species. The other four fish species had BRQs > 1 for eating only muscle, only skin, and eating both, indicating the potential risk caused by PCDD/F and dl-PCB. Amounts of the four fish species consumed should be decreased, and other sources of EPA and DHA should be selected.

Longitudinal changes in persistent organic pollutants (POPs) from 2001 to 2009 in a sample of elderly Swedish men and women

BACKGROUND

Prospective cohort studies evaluating the temporal trends of background-level persistent organic pollutants (POPs) and their potential negative health effects in humans are needed.

OBJECTIVE

The objectives of this study are to examine the five year longitudinal trend in chlorinated and brominated (Cl/Br) POP concentrations in a sample of elderly individuals and to investigate the relationship between gender, changes in body weight, plasma lipid levels and POP concentrations.

METHODS

In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, plasma samples were collected from the same individuals over a 5 year period. Originally 992 subjects (all aged 70) were sampled between 2001 and 2004 and 814 returning subjects (all aged 75) were sampled again from 2006 to 2009. Plasma concentrations of 16 polychlorinated biphenyls (PCBs), 5 organochlorine pesticides (OCPs), octachlorinated dibenzo-p-dioxin (OCDD), and one polybrominated diphenylether (BDE 47) were determined using high-throughput 96-well plate solid phase extraction and gas chromatography-high resolution mass spectrometry (GC-HRMS).

RESULTS

During the 5-year follow-up, plasma concentrations of all POPs significantly decreased (p < 0.00001). Median reductions ranged from 4% (PCB105) to 45% (PCB 99), with most reductions being in the 30-40% range. For most POPs, a larger decline was seen in men than in women. The relationship between the weight change and change in POP concentrations was generally negative, but a positive relationship between lipid levels and POP concentrations when expressed as wet-weight was observed. In general, similar changes in POP concentrations and their relationships to body weight were observed regardless of using either wet-weight (pg/mL) or lipid-normalized (ng/g lipid) concentrations.

CONCLUSION

In this longitudinal cohort study, gender and minor, but varying changes in body weight and lipid levels greatly influenced the individual-based changes in POP concentrations. In general, our findings suggest that men and women with larger decreases in body weight and greater increases in lipid levels have the slowest decline in body burden of POPs. Based on the results from this study, either wet-weight or lipid normalized concentrations can be used to determine the percent change in POP concentrations and their relationships to physiological changes and differences.

Editor's Highlight: PCB126 Exposure Increases Risk for Peripheral Vascular Diseases in a Liver Injury Mouse Model

The liver is vital for xenobiotic and endobiotic metabolism. Previously, we demonstrated that a compromised liver worsened toxicity associated with exposure to polychlorinated biphenyls (PCBs), through disruption of energy homeostasis. However, the role of a compromised liver in defining dioxin-like PCB126 toxicity on the peripheral vasculature and associated inflammatory diseases is yet to be studied. This study investigated the effects of PCB126 on vascular inflammation linked to hepatic dysfunction utilizing a liver injury mouse model. Male C57Bl/6 mice were fed either an amino acid control diet (CD) or a methionine-choline deficient (MCD) diet in this 14-week study. Mice were exposed to PCB126 (0.5 mg/kg) and analyzed for inflammatory, calorimetric and metabolic parameters. MCD diet-fed mice demonstrated steatosis, indicative of a compromised liver. Mice fed the MCD-diet and subsequently exposed to PCB126 manifested lower body fat mass, increased liver to body weight ratio and alterations in hepatic gene expression related to lipid and carbohydrate metabolism, implicating metabolic disturbances. PCB126-induced steatosis irrespective of the diet type, but only the MCD + PCB126 group exhibited steatohepatitis and fibrosis. Furthermore, PCB126 exposure in MCD-fed mice led to increased plasma inflammatory markers such as Icam-1, plasminogen activator inhibitor-1 and proatherogenic trimethylamine-N-oxide, suggesting inflammation of the peripheral vasculature that is characteristic of atherosclerosis. Taken together, our data provide new evidence of a link between a compromised liver, PCB-mediated hepatic inflammation and vascular inflammatory markers, suggesting that environmental pollutants can promote crosstalk between different organ systems, leading to inflammatory disease pathologies.

Endocrine-disrupting chemicals and risk of diabetes: an evidence-based review

The purpose of this study was to review the epidemiological and experimental evidence linking background exposure to a selection of environmental endocrine-disrupting chemicals (EDCs) with diabetes and impaired glucose metabolism. The review summarises the literature on both cross-sectional and prospective studies in humans, as well as experimental in vivo and in vitro studies. The findings were subjected to evidence grading according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) classification. We found >40 cross-sectional and seven prospective studies regarding EDCs and risk of diabetes. Taken together, there is moderate evidence for a relationship between exposure to dichlorodiphenyldichloroethylene (p,p'-DDE), a metabolite of the pesticide dichlorodiphenyltrichloroethane, and diabetes development. Regarding polychlorinated biphenyls (PCBs), it is likely that the rodent models used are not appropriate, and therefore the evidence is poorer than for p,p'-DDE. For other EDCs, such as bisphenol A, phthalates and perfluorinated chemicals, the evidence is scarce, since very few prospective studies exist. Brominated flame retardants do not seem to be associated with a disturbed glucose tolerance. Thus, evidence is accumulating that EDCs might be involved in diabetes development. Best evidence exists for p,p'-DDE. For other chemicals, both prospective studies and supporting animal data are still lacking.

Persistent Organochlorine Pollutants in Plasma, Blood Pressure, and Hypertension in a Longitudinal Study

Persistent organochlorine pollutants (POPs) have shown to be involved in the atherosclerotic process and to cause endothelial cell dysfunction. To assess longitudinally whether plasma concentrations of different POPs were associated with blood pressure and risk of hypertension in middle-aged women and men. Study subjects were 850 participants in the VIP (Västerbotten Intervention Programme) with 2 blood samples and blood pressure measurements, 10 years apart, during 1990 to 2003 (baseline) and during 2000 to 2013 (follow-up). Dioxin-like and nondioxin-like polychlorinated biphenyls (DL-PCBs, NDL-PCBs) and p,p'-dichlorodiphenyldichloroethylene (DDE) were measured. Associations were assessed using generalized estimating equations. At baseline sampling 49% and at follow-up 64% had hypertension. DL-PCBs and DDE, but not NDL-PCBs or hexachlorobenzene, were associated with hypertension. Only the association for DL-PCBs remained statistically significant after lipid-standardization and adjustment for body mass index and total serum lipids. The multivariable-adjusted odds ratio of hypertension based on repeated measurements were 1.52 (95% confidence interval, 1.08-2.13) for DL-PCBs (third versus first tertile of lipid-standardized POPs). In stratified adjusted analyses, odds ratio for those born after 1950 increased to 3.99 (95% confidence interval, 2.15-7.43), whereas no association was observed among those born earlier. Based on repeated measurements, the accumulated exposure to DL-PCBs and DDE, although less clear for the latter, may disrupt the normal blood pressure levels and increase the odds of hypertension. Moreover, individuals experiencing early-life POP exposure may be at elevated risk of vascular POP effects.

Aryl hydrocarbon receptor is activated in patients and mice with chronic kidney disease

Patients with chronic kidney disease (CKD) are exposed to uremic toxins and have an increased risk of cardiovascular disease. Some uremic toxins, like indoxyl sulfate, are agonists of the transcription factor aryl hydrocarbon receptor (AHR). These toxins induce a vascular procoagulant phenotype. Here we investigated AHR activation in patients with CKD and in a murine model of CKD. We performed a prospective study in 116 patients with CKD stage 3 to 5D and measured the AHR-Activating Potential of serum by bioassay. Compared to sera from healthy controls, sera from CKD patients displayed a strong AHR-Activating Potential; strongly correlated with eGFR and with the indoxyl sulfate concentration. The expression of the AHR target genes Cyp1A1 and AHRR was up-regulated in whole blood from patients with CKD. Survival analyses revealed that cardiovascular events were more frequent in CKD patients with an AHR-Activating Potential above the median. In mice with 5/6 nephrectomy, there was an increased serum AHR-Activating Potential, and an induction of Cyp1a1 mRNA in the aorta and heart, absent in AhR^-/- CKD mice. After serial indoxyl sulfate injections, we observed an increase in serum AHR-AP and in expression of Cyp1a1 mRNA in aorta and heart in WT mice, but not in AhR^-/- mice. Thus, the AHR pathway is activated both in patients and mice with CKD. Hence, AHR activation could be a key mechanism involved in the deleterious cardiovascular effects observed in CKD.

Serum persistent organic pollutants levels and stroke risk

Knowledge of environmental risk factors for stroke and their role are limited. We performed a case-cohort study to evaluate the association between serum persistent organic pollutants (POPs) level and stroke risk. 526 subcohort members and 111 stroke incidence cases were identified from the Korean Cancer Prevention Study-II. Serum levels of POPs were measured using gas chromatography/high-resolution mass spectrometry. The hazard ratios (HRs) for stroke (ischemic, hemorrhagic, and all stroke types) were estimated using the weighted Cox regression model. Age, sex, body mass index, smoking status, physical activity, family history of cardiovascular disease, and hypertension were adjusted in the weighted Cox regression model. After adjusting for potential confounding factors, increased risk for stroke was observed among participants with serum concentration of p,p'-DDE in the highest tertile compared to those in the lowest tertile (HR = 4.10, 95% CI: 1.58, 10.59). A similar association was estimated for PCB118 (HR = 2.33, 95% CI: 1.04, 5.22), PCB156 (HR = 3.42, 95% CI: 1.42, 8.23), and PCB138 (HR = 3.80, 95% CI: 1.48, 9.76). For TEQ, stroke was three times as likely to occur among subjects with TEQ in the highest tertile compared to those in the lowest tertile (HR = 3.12, 95% CI: 1.27, 7.65). PCBs were positively associated with ischemic stroke, but not with hemorrhagic stroke. Elevated serum POPs levels were associated with an increased risk of stroke, especially ischemic stroke.

Persistent Threats by Persistent Pollutants: Chemical Nature, Concerns and Future Policy Regarding PCBs-What Are We Heading For?

Polychlorinated biphenyl (PCB)-contaminated sites around the world affect human health for many years, showing long latency periods of health effects. The impact of the different PCB congeners on human health should not be underestimated, as they are ubiquitous, stable molecules and reactive in biological tissues, leading to neurological, endocrine, genetic, and systemic adverse effects in the human body. Moreover, bioaccumulation of these compounds in fatty tissues of animals (e.g., fish and mammals) and in soils/sediments, results in chronic exposure to these substances. Efficient destruction methods are important to decontaminate polluted sites worldwide. This paper provides an in-depth overview of (i) the history and accidents with PCBs in the 20th century, (ii) the mechanisms that are responsible for the hazardous effects of PCBs, and (iii) the current policy regarding PCB control and decontamination. Contemporary impacts on human health of historical incidents are discussed next to an up to date overview of the health effects caused by PCBs and their mechanisms. Methods to decontaminate sites are reviewed. Steps which lead to a policy of banning the production and distribution of PCBs are overviewed in a context of preventing future accidents and harm to the environment and human health.

Relationships between serum-induced AhR bioactivity or mitochondrial inhibition and circulating polychlorinated biphenyls (PCBs)

Metabolic syndrome and mitochondrial dysfunction have been linked to elevated serum levels of persistent organic pollutants (POPs). However, it is not clear which specific POPs contribute to aryl hydrocarbon receptor (AhR)-dependent bioactivity or inhibit mitochondrial function in human subjects. Here, we measured the cumulative bioactivity of AhR ligand mixture (AhR bioactivity) and the effects on mitochondrial function (ATP concentration) in recombinant Hepa1c1c7 cells incubated with raw serum samples obtained from 911 elderly subjects in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. Plasma concentrations of 30 POPs and plastic chemicals have previously been determined in the same PIVUS subjects. Linear regression analysis demonstrated that total toxic equivalence (TEQ) values and polychlorinated biphenyls (PCBs) were significantly correlated with AhR bioactivity (positively) and ATP concentration (negatively). Serum AhR bioactivities were positively associated with some PCBs, regardless of their dioxin-like properties, but only dioxin-like PCBs stimulated AhR bioactivity. By contrast, PCBs mediated a reduction in ATP content independently of their dioxin-like properties. This study suggests that AhR bioactivity and ATP concentrations in serum-treated cells may be valuable surrogate biomarkers of POP exposure and could be useful for the estimation of the effects of POPs on human health.

Monitoring and risk assessment of polychlorinated biphenyls (PCBs) in agricultural soil from two industrialized areas

For monitoring and risk assessment, levels and distributions of Σ₂₉ PCBs in paddy soil samples collected from Gwangyang (10 sites) and Ulsan (20 sites), heavily industrialized cities in Korea, were investigated using high-resolution gas chromatography/high-resolution mass spectrometry. Overall, total concentrations of Σ₂₉ PCBs in Gwangyang (216.4-978.6 pg g^-1 dw) and Ulsan (273.8-1824.1 pg g^-1 dw) were higher than those (106.6-222.6 pg g^-1 dw) in agricultural soil from Anseong in Korea. The TEQ (toxic equivalency) values from Gwangyang (0.06-0.40 ng TEQ kg^-1 dw) and Ulsan (0.06-0.22 ng TEQ kg^-1 dw) were higher than those (0.04-0.11 ng TEQ kg^-1 dw) in Anseong but lower than the WHO threshold level (20 ng TEQ kg^-1). However, one of the most toxic congeners, PCB 126, gave the highest concentration, possibly posing a risk to the biota. Seven indicator PCB congeners contributed to 50-80% of the total concentration of Σ₂₉ PCBs, indicating the 7 PCBs can be used as valuable indicators for monitoring. The principal component analysis and cluster analysis for the homologue profiles of PCBs indicated that all the samples from both cities had the similar PCB contamination patterns, and the major sources of the PCB contamination were most likely from the usage of Aroclor 1254 than those of Aroclors 1242 and 1260. These PCB technical mixtures were possibly significantly used by various industries including iron and steel industries in Gwangyang and petrochemical and shipbuilding industries in Ulsan.

Differences in the clinical manifestations and short-term prognosis of acute cerebral infarction after exposure to Agent Orange

Background

Agent Orange (AO) is the code name for one of the herbicides and defoliants used in the Vietnam War. Studies conducted thus far show a significant correlation between AO and the occurrence of cardiovascular diseases. But there is little data on the association between AO and stroke, and limited studies have targeted patient groups exposed to AO.

Method

Bohun medical center Institutional Review Board (IRB) approved the study. (ID: 341) We studied patients with acute ischemic stroke within 7 days of onset in VHS medical center and 4 other general hospitals. Among them, 91 consecutive patients with previous exposure to AO were evaluated. For controlled group, 288 patients with no history of AO exposure were chosen.

Result

There were 49 (44.0 %) DM patient with a higher frequency in the exposure group (93 (32.3 %) in control P = 0.045). There were 6 (6.6 %) hyperlipidemia in exposure group and 69 (24.0 %) in control. (P < 0.002). Small vessel occlusion was the most common subtype (36, 39.6 %) in exposure group but in control group, the large artery atherosclesosis was (120, 41.7 %) (P = 0.014).

The NIHSS of the exposure group on admission showed lower scores (median values, 2 and 4, respectively; P = 0.003). The median mRS was 1 for the exposure group and 2 for the control group, at discharge and after 3 months. After 3 months of discharge, 55 (60.4 %) in the exposure group and 171 (59.4 %) in the control group showed below mRS 1 (P = 0.001).

Conclusion

This study targeted patients who are Vietnam veteran. There is some difference in vascular risk factors and clinical manifestations suggest AO exposure has contributed to a certain extent to the stroke.

Polychlorinated biphenyls: New evidence from the last decade

Millions of pounds of polychlorinated biphenyl (PCB) compounds have been produced in multiple countries for industrial applications over the last several decades. PCB exposure induces various adverse health effects in animals and humans. Environmental and occupational exposures to PCBs have been associated with liver, kidney, endocrine, and neurodevelopmental adverse effects. We have collected and reviewed animal and human data cited in the US National Library of Medicine from 2000 to 2010. In brief, our review shows new evidence, that is, in animal studies, exposure to one of the PCBs, A1221, induces a significant alteration of serum luteinizing hormone. The effects were more profound in the F2 generation, particularly with respect to fluctuations in hormones and reproductive tract tissues across the estrous cycle. Morphological analyses of brain tissue from rats exposed to A1254 confirmed the results of an earlier work which showed that the relative size of the intra- and infrapyramidal (II-P) mossy fibers was smaller than that in the controls and also reduction in growth was selective for the II-P mossy fibers. PCB exposure increased anogenital distance and prostate size but decreased epididymal weight, epididymal sperm count, and motile epididymal sperm count. No effects were observed on testicular weight or size. The epidemiological data showed an association between diabetes mellitus prevalence and elevated concentrations of PCB 153. Additionally, prenatal PCB exposure studies were associated with a smaller thymic index at birth and could adversely affect immune responses to childhood vaccinations and resistance to respiratory infections. PCB exposure was also reported to adversely affect enamel development in children in a dose-dependent manner. Because PCBs and their metabolites are potential health hazards, understanding the risk factors associated with individual PCBs, PCB mixtures, and PCB metabolites is important. PCB exposures of vulnerable populations (pregnant women, fetuses, infants, and children) are of particular concern because of heightened sensitivity during this period of brain development.

Dioxin-like pollutants increase hepatic flavin containing monooxygenase (FMO3) expression to promote synthesis of the pro-atherogenic nutrient biomarker trimethylamine N-oxide from dietary precursors

The etiology of cardiovascular disease (CVD) is impacted by multiple modifiable and non-modifiable risk factors including dietary choices, genetic predisposition, and environmental exposures. However, mechanisms linking diet, exposure to pollutants, and CVD risk are largely unclear. Recent studies identified a strong link between plasma levels of nutrient-derived Trimethylamine N-oxide (TMAO) and coronary artery disease. Dietary precursors of TMAO include carnitine and phosphatidylcholine, which are abundant in animal-derived foods. Dioxin-like pollutants can upregulate a critical enzyme responsible for TMAO formation, hepatic flavin containing monooxygenase 3 (FMO3), but a link between dioxin-like PCBs, upregulation of FMO3, and increased TMAO has not been reported. Here, we show that mice exposed acutely to dioxin-like PCBs exhibit increased hepatic FMO3 mRNA, protein, as well as an increase in circulating levels of TMAO following oral administration of its metabolic precursors. C57BL/6 mice were exposed to 5μmol PCB 126/kg mouse weight (1.63mg/kg). At 48h post-PCB exposure, mice were subsequently given a single gavage of phosphatidylcholine dissolved in corn oil. Exposure to 5 μmole/kg PCB 126 resulted in greater than 100-fold increase in FMO3 mRNA expression, robust induction of FMO3 protein, and a 5-fold increase in TMAO levels compared with vehicle treated mice. We made similar observations in mice exposed to PCB 77 (49.6mg/kg twice); stable isotope tracer studies revealed increased formation of plasma TMAO from an orally administered precursor trimethylamine (TMA). Taken together, these observations suggest a novel diet-toxicant interaction that results in increased production of a circulating biomarker of cardiovascular disease risk.

Dietary exposure to polychlorinated biphenyls and risk of myocardial infarction in men - A population-based prospective cohort study

BACKGROUND

Major food contaminants such as polychlorinated biphenyls (PCBs) are proposed to play a role in the etiology of cardiovascular disease (CVD), but to date the impact of PCBs on cardiovascular health need to be explored.

METHODS AND RESULTS

We assessed the association between validated food frequency questionnaire-based estimates of dietary PCB exposure and risk of myocardial infarction, ascertained through register-linkage, among 36,759 men from the population-based Swedish Cohort of Men, free of cardiovascular disease, diabetes and cancer at baseline (1997). Relative risks were adjusted for known cardiovascular risk factors, long-chain omega-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) and methyl mercury exposure. During 12years of follow-up (433,243 person-years), we ascertained 3005 incident cases of myocardial infarction (654 fatal). Compared with the lowest quintile of dietary PCB exposure (median 113ng/day), men in the highest quintile (median 436ng/day) had multivariable-adjusted relative risks of 1.74 (95% confidence interval [CI], 1.30-2.33; p-trend<0.001) for total and 1.97 (95% CI 1.42-2.75; p-trend<0.001) for non-fatal myocardial infarction. In mutually adjusted models, dietary PCB exposure was associated with an increased risk of myocardial infarction, while the intake of long-chain omega-3 fish fatty acids was associated with a decreased risk. We also observed an effect modification by adiposity on the association between of dietary PCB exposure and myocardial infarction, with higher risk among lean men (p value for interaction =0.03).

CONCLUSIONS

Exposure to PCBs via diet was associated with increased risk of myocardial infarction in men.

The Effect of Exposure to Persistent Organic Pollutants on Metabolic Health among KOREAN Children during a 1-Year Follow-Up

Previous evidence suggests the potential for adverse effects of persistent organic pollutants (POPs) on metabolic health even at low-dose exposure levels common among the general population, but there is less evidence of these associations among children. Therefore, as part of a prospective cohort study, 214 children were measured for POPs exposure. After the 1-year follow-up, we assessed the effect of circulating POPs exposure among 158 children aged 7-9 years (at baseline) on the change of metabolic components of metabolic syndrome using multiple regression analysis. In addition, we calculated the continuous metabolic syndrome (cMetS) score and assessed the variation among individuals by POPs exposure. The concentrations of marker polychlorinated biphenyls (PCBs) were significantly associated with increased change in diastolic blood pressure (BP) and triglyceride levels during a 1-year follow-up, after controlling for sex, age, household income, and change in body mass index. Total PCBs also showed a marginal association with increasing cMetS score from the baseline. Of the metabolic components, change in diastolic BP over time showed a notable association with specific PCBs, but no association with organochlorine pesticides. Here, we found that low-dose exposures to PCBs among children in the general population could negatively influence metabolic health, particularly diastolic BP. Increased disease sensitivity during childhood can continue to adulthood, thus, these results support the need for continuous assessment of the health impact of POPs.

Chronic cardiovascular disease-associated gene network analysis in human umbilical vein endothelial cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

The association of dioxin exposure with increased morbidity or mortality of chronic cardiovascular diseases (CVDs) has been established by many epidemiological studies. However, the precise global gene expression alterations caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the cardiovascular system need to be further elucidated. In this study, we profiled the gene expression of human umbilical vein endothelial cells (HUVECs) exposed to different concentrations of TCDD by high-throughput sequencing. Expression of 1,838 genes was changed significantly after TCDD stimulation. The FunDO analysis suggested that some CVDs were highly associated with TCDD treatment, including atherosclerosis, thromboangiitis obliterans, pulmonary arterial hypertension (PAH), and hypertension. KEGG pathway analysis showed that many genes in the signaling pathways of vascular smooth muscle contraction and apoptosis were altered distinctly. In addition, we revealed evidence regarding the gene network changes of chronic CVDs including atherosclerosis, thrombosis, myocardial infarction (MI), hypertension, and PAH in TCDD-exposed HUVECs. We found that gene expression of β1-adrenoceptors (ADRB1), β2-adrenoceptors (ADRB2), endothelin-converting enzyme 1 (ECE1), and endothelin-1 gene (EDN1) that are involved in the blood pressure regulation pathway decreased apparently under TCDD treatment. Moreover, the transcripts of interleukin 1 beta (IL-1β) and tumor necrosis factor α (TNFα), which are related to atherosclerosis, were up-regulated by TCDD stimulation. In addition, the transcripts of Homo sapiens collagen, type IV, alpha 1 (COL4A1), and isoforms that trigger the MI pathway were up-regulated after TCDD exposure. Finally, we found enhanced platelet-derived growth factor (PDGF) and signal transducer and activator of transcription 5 (Stat5) expression with TCDD treatment in endothelial cells, which are involved in PAH induced by vascular injury.

Absorption of PCB126 by upper airways impairs G protein-coupled receptor-mediated immune response

PCB126 is a dioxin-like polychlorinated biphenyl (PCB) environmental pollutant with a significant impact on human health, as it bioaccumulates and causes severe toxicity. PCB126-induced immune toxicity has been described, although the mechanisms have not been fully elucidated. In this study, an in vivo protocol of PCB126 intoxication into male Wistar rats by intranasal route was used, which has not yet been described. The intoxication was characterised by PCB126 accumulation in the lungs and liver, and enhanced aryl hydrocarbon receptor expression in the liver, lungs, kidneys, and adipose tissues. Moreover, an innate immune deficiency was characterised by impairment of adhesion receptors on blood leukocytes and by reduced blood neutrophil locomotion and oxidative burst activation elicited by ex vivo G protein-coupled receptor (GPCR) activation. Specificity of PCB126 actions on the GPCR pathway was shown by normal burst oxidative activation evoked by Toll-like receptor 4 and protein kinase C direct activation. Moreover, in vivo PCB180 intoxication did not alter adhesion receptors on blood leukocytes either blood neutrophil locomotion, and only partially reduced the GPCR-induced burst oxidative activation on neutrophils. Therefore, a novel mechanism of in vivo PCB126 toxicity is described which impairs a pivotal inflammatory pathway to the host defence against infections.

Endosulfan activates the extrinsic coagulation pathway by inducing endothelial cell injury in rats

Endosulfan, a persistent organic pollutant, is widely used in agriculture as a pesticide. The aim of the present study was to evaluate the blood toxicity of different doses of endosulfan in Wistar rats. The experimental sample was composed of four groups, a control group that did not receive endosulfan and three endosulfan-exposed groups that respectively received 1, 5, or 10 mg/kg/day (doses below LD50), of endosulfan for 21 days. The results showed that endosulfan significantly decreased the prothrombin time (PT) and upregulated the activated coagulation factors VIIa, Xa, and XIIIa; thrombin-antithrombin complex (TAT); and P-selectin. Plasma levels of tissue factor (TF) and malondialdehyde (MDA) were increased in the endosulfan groups. The activated partial thromboplastin time (APTT) and the level of activated coagulation factor IXa showed no obvious changes. Immunohistochemical results showed increased expression of von Willebrand factor (vWF) and the inflammatory cytokine interleukin (IL)-1β in the groups exposed to endosulfan. The pathology and electron microscopy results showed impaired vascular tissue accompanied by the exfoliation of endothelial cells and mitochondrial damage in the endosulfan-exposed groups. In summary, our results suggest that endosulfan damages endothelial cells via oxidative stress and the inflammatory response, leading to the release of TF and vWF into the blood. The TF and vWF in the blood may activate extrinsic coagulation factors and platelets, thus triggering the extrinsic coagulation pathway. There were no obvious effects on the intrinsic coagulation pathway.

Association of Prenatal Exposure to Persistent Organic Pollutants with Obesity and Cardiometabolic Traits in Early Childhood: The Rhea Mother-Child Cohort (Crete, Greece)

BACKGROUND

Prenatal exposure to endocrine-disrupting chemicals such as persistent organic pollutants (POPs) may increase risk of obesity later in life.

OBJECTIVE

We examined the relation of in utero POPs exposure to offspring obesity and cardiometabolic risk factors at 4 years of age in the Rhea mother-child cohort in Crete, Greece (n = 689).

METHODS

We determined concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and hexachlorobenzene (HCB) in first-trimester maternal serum. We measured child weight, height, waist circumference, skinfold thicknesses, blood pressure (BP), blood levels of lipids, C-reactive protein, and adipokines at 4 years of age. Childhood obesity was defined using age- and sex-specific cut points for body mass index (BMI) as recommended by the International Obesity Task Force.

RESULTS

On multivariable regression analyses, a 10-fold increase in HCB was associated with a higher BMI z-score (adjusted β = 0.49; 95% CI: 0.12, 0.86), obesity [relative risk (RR) = 8.14; 95% CI: 1.85, 35.81], abdominal obesity (RR = 3.49; 95% CI: 1.08, 11.28), greater sum of skinfold thickness (β = 7.71 mm; 95% CI: 2.04, 13.39), and higher systolic BP (β = 4.34 mmHg; 95% CI: 0.63, 8.05) at 4 years of age. Prenatal DDE exposure was associated with higher BMI z-score (β = 0.27; 95% CI: 0.04, 0.5), abdominal obesity (RR = 3.76; 95% CI: 1.70, 8.30), and higher diastolic BP (β = 1.79 mmHg; 95% CI: 0.13, 3.46). PCBs were not significantly associated with offspring obesity or cardiometabolic risk factors.

CONCLUSIONS

Prenatal exposure to DDE and HCB was associated with excess adiposity and higher blood pressure levels in early childhood.

Dietary exposure to polychlorinated biphenyls and risk of myocardial infarction - a population-based prospective cohort study

BACKGROUND

Fish consumption may promote cardiovascular health. The role of major food contaminants, such as polychlorinated biphenyls (PCBs) common in fatty fish, is unclear. We assessed the association between dietary PCB exposure and risk of myocardial infarction taking into account the intake of long-chain omega-3 fish fatty acids.

METHODS

In the prospective population-based Swedish Mammography Cohort, 33,446 middle-aged and elderly women, free from cardiovascular disease, cancer and diabetes at baseline (1997) were followed-up for 12 years. Validated estimates of dietary PCB exposure and intake of fish fatty acids (eicosapentaenoic acid and docosahexaenoic acid; EPA-DHA) were obtained via a food frequency questionnaire at baseline.

RESULTS

During follow-up 1386 incident cases of myocardial infarction were ascertained through register-linkage. Women in the highest quartile of dietary PCB exposure (median 286 ng/day) had a multivariable-adjusted RR of myocardial infarction of 1.21 (95% confidence interval [CI], 1.01-1.45) compared to the lowest quartile (median 101 ng/day) before, and 1.58 (95% CI, 1.10-2.25) after adjusting for EPA-DHA. Stratification by low and high EPA-DHA intake, resulted in RRs 2.20 (95% CI, 1.18-4.12) and 1.73 (95% CI, 0.81-3.69), respectively comparing highest PCB tertile with lowest. The intake of dietary EPA-DHA was inversely associated with risk of myocardial infarction after but not before adjusting for dietary PCB.

CONCLUSION

Exposure to PCBs was associated with increased risk of myocardial infarction, while some beneficial effect was associated with increasing EPA and DHA intake. To increase the net benefits of fish consumption, PCB contamination should be reduced to a minimum.

Persistent organic pollutants are related to the change in circulating lipid levels during a 5 year follow-up

When reporting circulating levels of persistent organic pollutants (POPs), usually lipid-normalized values are given. However, animal experiments and some human data indicate that exposure to POPs may change lipid values. The aim of the present study is to investigate if POP levels can predict future changes in levels of circulating lipids. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, lipids were measured at age 70 and at age 75 in 598 subjects without lipid-lowering medication. Twenty-three different POPs, including 16 polychlorinated biphenyls (PCBs), five organochlorine pesticides, one dioxin (OCDD) and one flame retardant brominated compound (BDE47) were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) at age 70. Strong relationships were seen among the baseline levels of the non-dioxin-like PCBs 194, 206 and 209 and the degree of increase in total serum cholesterol and LDL-cholesterol during the 5 year follow-up. These relationships were generally stronger when lipid-normalized levels were used compared to wet-weight based levels. On the contrary, for two of the pesticides, hexachlorobenzene and trans-nonachlordane, levels were inversely related to the change in LDL-cholesterol, with strongest associations found using wet-weight based levels. PCBs 194, 206 and 209 were inversely related to the change in HDL-cholesterol, in particular for wet-weight based levels. However, these relationships were only significant for wet-weight PCB 194 following adjustment for multiple testing. None of the POPs was related to the change in serum triglycerides. When investigating the association between the change in total serum cholesterol and LDL-cholesterol across different categories of change in BMI, we noted robust results especially in the group with stable BMI, suggesting that the observed relationships were not due to fluctuations in BMI over time. In conclusion, POPs are related to the change in lipids over time, especially LDL-cholesterol. This may explain why POP exposure previously has been linked to atherosclerosis and cardiovascular disease.

Exposure to a northern contaminant mixture (NCM) alters hepatic energy and lipid metabolism exacerbating hepatic steatosis in obese JCR rats

Non-alcoholic fatty liver disease (NAFLD), defined by the American Liver Society as the buildup of extra fat in liver cells that is not caused by alcohol, is the most common liver disease in North America. Obesity and type 2 diabetes are viewed as the major causes of NAFLD. Environmental contaminants have also been implicated in the development of NAFLD. Northern populations are exposed to a myriad of persistent organic pollutants including polychlorinated biphenyls, organochlorine pesticides, flame retardants, and toxic metals, while also affected by higher rates of obesity and alcohol abuse compared to the rest of Canada. In this study, we examined the impact of a mixture of 22 contaminants detected in Inuit blood on the development and progression of NAFLD in obese JCR rats with or without co-exposure to10% ethanol. Hepatosteatosis was found in obese rat liver, which was worsened by exposure to 10% ethanol. NCM treatment increased the number of macrovesicular lipid droplets, total lipid contents, portion of mono- and polyunsaturated fatty acids in the liver. This was complemented by an increase in hepatic total cholesterol and cholesterol ester levels which was associated with changes in the expression of genes and proteins involved in lipid metabolism and transport. In addition, NCM treatment increased cytochrome P450 2E1 protein expression and decreased ubiquinone pool, and mitochondrial ATP synthase subunit ATP5A and Complex IV activity. Despite the changes in mitochondrial physiology, hepatic ATP levels were maintained high in NCM-treated versus control rats. This was due to a decrease in ATP utilization and an increase in creatine kinase activity. Collectively, our results suggest that NCM treatment decreases hepatic cholesterol export, possibly also increases cholesterol uptake from circulation, and promotes lipid accumulation and alters ATP homeostasis which exacerbates the existing hepatic steatosis in genetically obese JCR rats with or without co-exposure to ethanol.

Dietary exposure to polychlorinated biphenyls is associated with increased risk of stroke in women

OBJECTIVE

The potentially beneficial effects of fish consumption on stroke may be modified by major food contaminants in fish. Polychlorinated biphenyls (PCBs) in particular are proposed to play a role in the aetiology of stroke. The aim of this study was to assess the association between dietary PCB exposure and stroke risk with the intake of long-chain omega-3 fish fatty acids and fish consumption.

DESIGN

The prospective population-based Swedish Mammography Cohort was examined. It was comprised of 34,591 women free of cardiovascular diseases and cancer at baseline in 1997 and followed up for 12 years. Validated estimates of dietary PCB exposure were obtained via a food frequency questionnaire at baseline. Incident cases of stroke were ascertained through register linkage.

RESULTS

During 12 years of follow-up (397,309 person-years), there were 2015 incident cases of total stroke (1532 ischaemic strokes, 216 intracerebral haemorrhages, 94 subarachnoid haemorrhages and 173 unspecified strokes). Multivariable-adjusted relative risks (RR), controlled for known stroke risk factors and fish consumption, were 1.67 [95% confidence interval (CI), 1.29-2.17] for total stroke, 1.61 (95% CI, 1.19-2.17) for ischaemic stroke and 2.80 (95% CI, 1.42-5.55) for haemorrhagic stroke for women in the highest quartile of dietary PCB exposure (median 288 ng day(-1) ) compared with women in the lowest quartile (median 101 ng day(-1) ).

CONCLUSION

Dietary exposure to PCBs was associated with an increased stroke risk in women, especially haemorrhagic stroke. The results provide important information regarding the risk-benefit analysis of fish consumption, particularly for cerebrovascular disease prevention.

Environmental endocrine disruption of energy metabolism and cardiovascular risk

Rates of metabolic diseases have increased at an astounding rate in recent decades. Even though poor diet and physical inactivity are central drivers, these lifestyle changes alone fail to fully account for the magnitude and rapidity of the epidemic. Thus, attention has turned to identifying novel risk factors, including the contribution of environmental endocrine disrupting chemicals. Epidemiologic and preclinical data support a role for various contaminants in the pathogenesis of diabetes. In addition to the vascular risk associated with dysglycemia, emerging evidence implicates multiple pollutants in the pathogenesis of atherosclerosis and cardiovascular disease. Reviewed herein are studies linking endocrine disruptors to these key diseases that drive significant individual and societal morbidity and mortality. Identifying chemicals associated with metabolic and cardiovascular disease as well as their mechanisms of action is critical for developing novel treatment strategies and public policy to mitigate the impact of these diseases on human health.

Dietary antioxidants (selenium and N-acetylcysteine) modulate paraoxonase 1 (PON1) in PCB 126-exposed rats

Environmental pollutants polychlorinated biphenyls (PCBs), especially dioxin-like PCBs, cause oxidative stress and associated toxic effects, including cancer and possibly atherosclerosis. We previously reported that PCB 126, the most potent dioxin-like PCB congener, not only decreases antioxidants such as hepatic selenium (Se), Se-dependent glutathione peroxidase, and glutathione (GSH) but also increases levels of the antiatherosclerosis enzyme paraoxonase 1 (PON1) in liver and serum. To probe the interconnection of these three antioxidant systems, Se, GSH, and PON1, we examined the influence of varying levels of dietary Se and N-acetylcysteine (NAC), a scavenger of reactive oxygen species (ROS) and precursor for GSH synthesis, on PON1 in the absence and presence of PCB 126 exposure. Male Sprague-Dawley rats, fed diets with differing Se levels (0.02, 0.2, or 2 ppm) or NAC (1%), were treated with a single intraperitoneal injection of corn oil or various doses of PCB 126 and euthanized 2 weeks later. PCB 126 significantly increased liver PON1 mRNA, protein level and activity, and serum PON1 activity in all dietary groups but did not consistently increase thiobarbituric acid levels (thiobarbituric acid reactive substances, TBARS), an indicator of lipid oxidation and oxidative stress, in liver or serum. Inadequate (high or low) dietary Se decreased baseline and PCB 126-induced aryl hydrocarbon receptor (AhR) expression but further increased PCB 126-induced cytochrome P450 1A1 (CYP1A1) expression, the enzyme believed to be the cause for PCB 126-induced oxidative stress. In addition, a significant inverse relationship was observed not only between dietary Se levels and PON1 mRNA and PON1 activity but also with TBARS levels in the liver, suggesting significant antioxidant protection from dietary Se. NAC lowered serum baseline TBARS levels in controls and increased serum PON1 activity but lowered liver PON1 activities in animals treated with 1 μmol/kg PCB 126, suggesting antioxidant activity by NAC primarily in serum. These results also show an unexpected predominantly inverse relationship between Se or NAC and PON1 during control and PCB 126 exposure conditions. These interactions should be further explored in the development of dietary protection regimens.

The aryl hydrocarbon receptor-activating effect of uremic toxins from tryptophan metabolism: a new concept to understand cardiovascular complications of chronic kidney disease

Patients with chronic kidney disease (CKD) have a higher risk of cardiovascular diseases and suffer from accelerated atherosclerosis. CKD patients are permanently exposed to uremic toxins, making them good candidates as pathogenic agents. We focus here on uremic toxins from tryptophan metabolism because of their potential involvement in cardiovascular toxicity: indolic uremic toxins (indoxyl sulfate, indole-3 acetic acid, and indoxyl-β-d-glucuronide) and uremic toxins from the kynurenine pathway (kynurenine, kynurenic acid, anthranilic acid, 3-hydroxykynurenine, 3-hydroxyanthranilic acid, and quinolinic acid). Uremic toxins derived from tryptophan are endogenous ligands of the transcription factor aryl hydrocarbon receptor (AhR). AhR, also known as the dioxin receptor, interacts with various regulatory and signaling proteins, including protein kinases and phosphatases, and Nuclear Factor-Kappa-B. AhR activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin and some polychlorinated biphenyls is associated with an increase in cardiovascular disease in humans and in mice. In addition, this AhR activation mediates cardiotoxicity, vascular inflammation, and a procoagulant and prooxidant phenotype of vascular cells. Uremic toxins derived from tryptophan have prooxidant, proinflammatory, procoagulant, and pro-apoptotic effects on cells involved in the cardiovascular system, and some of them are related with cardiovascular complications in CKD. We discuss here how the cardiovascular effects of these uremic toxins could be mediated by AhR activation, in a “dioxin-like” effect.

Circulating levels of p,p'-DDE are related to prevalent hypertension in the elderly

BACKGROUND

Polychlorinated biphenyls (PCBs) and dioxin given to experimental animals increase the blood pressure. We therefore investigated if circulating levels of persistent organic pollutants (POPs) were related to hypertension in a population-based sample of men and women.

METHODS

One thousand and sixteen subjects aged 70 years were investigated in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Twenty-three POPs were analyzed using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). Hypertension was defined as a systolic blood pressure ≥140mmHg or a diastolic blood pressure ≥90mmHg, and/or use of antihypertensive medication.

RESULTS

Seven hundred and thirty-two subjects (72%) showed hypertension. When the POPs were treated as continuous variables and adjusted for gender only, two PCBs with a low number of chlorine atoms (PCB 105 and 118) were related to prevalent hypertension. Also the OC pesticide p,p'-DDE was related to hypertension. The strongest of these associations was seen for p,p'-DDE (OR 1.35 for a 1 SD change, 95% CI 1.17-1.56, p<0.0001). Following further adjustment also for BMI, smoking status, education level and exercise habits, only p,p'-DDE was still significantly related to hypertension (OR 1.23 for a 1 SD change, 95% CI 1.06-1.43, p=0.006).

CONCLUSION

In this cross-sectional analysis of an elderly population, high levels of circulating levels of p,p'-DDE were associated with prevalent hypertension, further strengthening the experimental findings that POPs might influence blood pressure.