Persistent organic pollutants and inflammatory markers in a cross-sectional study of elderly Swedish people: the PIVUS cohort

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Hematological indices as indicators of inflammation induced by exposure to pesticides

Pesticide toxicity, both acute and chronic, is a global public health concern. Pesticides are involved in abnormal inflammatory responses by interfering with the normal physiology and metabolic status of cells. In this regard, inflammatory indices aggregate index of systemic inflammation (AISI), monocyte-to-high-density lipoprotein ratio, monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte platelet ratio (NLPR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index (SIRI) have been used as predictive markers of inflammatory status in several diseases and also in acute poisoning events. This study aimed to determine systemic inflammation indices and their relationship with pesticide exposure from urban sprayers in 302 individuals categorized into three groups (reference group and moderate and high exposure groups). The data suggest that the AISI, MLR, NLPR, and SIRI indices were significantly higher in the exposed groups compared with the reference group. In conclusion, this study proposes that inflammation indices warrant further attention in order to assess their value as early biomarkers of acute and chronic pesticide intoxication.

Public healthcare costs associated with long-term exposure to mixtures of persistent organic pollutants in two areas of Southern Spain: A longitudinal analysis

BACKGROUND

Polychlorinated biphenyls and organochlorine pesticides are persistent organic pollutants (POPs) that had been banned or restricted in many countries, including Spain. However, their ubiquity still poses environmental and human health threats.

OBJECTIVE

To longitudinally explore public healthcare costs associated with long-term exposure to a mixture of 8 POPs in a cohort of residents of two areas of Granada Province, Southern Spain.

METHODS

Longitudinal study in a subsample (n = 385) of GraMo adult cohort. Exposure assessment was performed by analyzing adipose tissue POP concentrations at recruitment. Average primary care (APC) and average hospital care (AHC) expenditures of each participant over 14 years were estimated using the data from their medical records. Data analyses were performed by robust MM regression, weighted quantile sum regression (WQS) and G-computation analysis.

RESULTS

In the adjusted robust MM models for APC, most POPs showed positive beta coefficients, being Hexachlorobenzene (HCB) significantly associated (β: 1.87; 95% Confidence interval (95%CI): 0.17, 3.57). The magnitude of this association increased (β: 3.72; 95%CI: 0.80, 6.64) when the analyses were restricted to semi-rural residents, where β-HCH was also marginally-significantly associated to APC (β: 3.40; 95%CI: -0.10, 6.90). WQS revealed a positive but non-significant mixture association with APC (β: 0.14; 95%CI: -0.06, 0.34), mainly accounted for by β-HCH (54%) and HCB (43%), that was borderline-significant in the semi-rural residents (β: 0.23; 95%CI: -0.01, 0.48). No significant results were observed in G-Computation analyses.

CONCLUSION

Long-term exposure to POP mixtures might represent a modifiable factor increasing healthcare costs, thus affecting the efficiency of the healthcare systems. However, and owing the complexity of the potential causal pathways and the limitations of the present study, further research is warranted to fully elucidate ascertain whether interventions to reduce human exposure should be considered in healthcare policies.

Screening of ToxCast Chemicals Responsible for Human Adverse Outcomes with Exposure to Ambient Air

Air pollution poses a major threat to global public health. Although there have been a few investigations into the relationships between organic pollutants and adverse outcomes, the responsible components and molecular mechanisms may be ignored. In this study, a suspect screening method combining comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF MS) with the Toxicity Forecaster (ToxCast) database was applied to analyze complex hydrophobic compounds in ambient air and prospectively figure out toxicologically significant compounds. Seventy-six ToxCast compounds were screened, including seven pollutants receiving less attention and five chemicals never published in the air previously. Given the concentrations, bioactivities, as well as absorption, distribution, metabolism, and excretion properties in vivo, 29 contaminants were assigned high priority since they had active biological effects in the vascular, lung, liver, kidney, prostate, and bone tissues. Phenotypic linkages of key pollutants to potential mechanistic pathways were explored by systems toxicology. A total of 267 chemical-effect pathways involving 29 toxicants and 31 molecular targets were mapped in bipartite network, in which 12 key pathogenic pathways were clarified, which not only provided evidence supporting the previous hypothesis but also provided new insights into the molecular targets. The results would facilitate the development of pollutant priority control, population intervention, and clinical therapeutic strategies so as to substantially reduce human health hazards induced by urban air.

The associations between endocrine disrupting chemicals and markers of inflammation and immune responses: A systematic review and meta-analysis

Exposure to endocrine disrupting chemicals (EDCs) may lead to dysregulated inflammatory responses, however, the detailed relationship between different EDCs and inflammation remains unclear. A systematic review and meta-analysis was conducted to evaluate the associations between four types of EDCs (bisphenol A (BPA), phthalates (PAEs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs)) and markers of inflammation and immune responses in humans. Three databases were searched, and 36 studies with a total of 22055 participants were included. The associations between EDCs and 26 inflammation-related acute phase proteins and cytokines were analyzed. The results demonstrated that exposure to BPA was positively associated with circulating levels of C-reactive protein (CRP) and interleukin (IL)-6. Exposure to PAEs was associated with elevated levels of CRP, IL-6 and IL-10. Subgroup analysis found that three PAE metabolites mono-benzyl phthalate (MBzP), mono-isobutyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP) were directly associated with a higher level of CRP, and two other PAE metabolites mono-carboxyisononyl phthalate (MCNP) and mono-3-carboxypropyl phthalate (MCPP) were positively associated with IL-6. The positive associations between PAEs and CRP, IL-6 and IL-10 were significant in the high-molecular-weight phthalate (HMWP) exposure group, not the low-molecular-weight phthalate (LMWP) exposure group. Exposure to OCPs was positively associated with CRP, IL-1β, IL-2, and IL-10. No significant association was found between PCBs and inflammatory markers. These findings demonstrate that exposure to EDCs is closely linked to dysregulated inflammatory responses. More studies should be conducted in the future to get a comprehensive view of the associations between different EDCs and inflammation, and investigations on the underlying mechanisms are needed.

Low-dose PCB126 exposure disrupts cardiac metabolism and causes hypertrophy and fibrosis in mice

The residue of polychlorinated biphenyls (PCBs) exists throughout the environment and humans are subject to long-term exposure. As such, the potential environmental and health risk caused by low-dose exposure to PCBs has attracted much attention. 3, 3', 4, 4', 5-pentachlorobiphenyl (PCB126), the highest toxicity compound among dioxin-like-PCBs, has been widely used and mass-produced. Cardiotoxicity is PCB126's crucial adverse effect. Maintaining proper metabolism underlies heart health, whereas the impact of PCB126 exposure on cardiac metabolic patterns has yet to be elucidated. In this study, we administered 0.5 and 50 μg/kg bw of PCB126 to adult male mice weekly by gavage for eight weeks. Pathological results showed that low-dose PCB126 exposure induced heart injury. Metabolomic analysis of the heart tissue exposed to low-dose PCB126 identified 59 differential metabolites that were involved in lipid metabolism, amino acid metabolism, and the tricarboxylic acid (TCA) cycle. Typical metabolomic characteristic of cardiac hypertrophy was reflected by accumulation of fatty acids (e.g. palmitic, palmitoleic, and linoleic acid), and disturbance of carbohydrates including D-glucose and intermediates in TCA cycle (fumaric, succinic, and citric acid). Low-dose PCB126 exposure increased glycine and threonine, the amino acids necessary for the productions of collagen and elastin. Besides, PCB126-exposed mice exhibited upregulation of collagen synthesis enzymes and extracellular matrix proteins, indicative of cardiac fibrosis. Moreover, the expression of genes related to TGFβ/PPARγ/MMP-2 signaling pathway was perturbed in the PCB126-treated hearts. Together, our results reveal that low-dose PCB126 exposure disrupts cardiac metabolism correlated with hypertrophy and fibrosis. This study sheds light on the underlying mechanism of PCBs' cardiotoxicity and identifies potential sensitive biomarkers for environmental monitoring.

Urinary Polycyclic Aromatic Hydrocarbon Metabolites Are Associated with Biomarkers of Chronic Endocrine Stress, Oxidative Stress, and Inflammation in Adolescents: FLEHS-4 (2016-2020)

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants of public health concern. Multiple biological mechanisms have been hypothesized to contribute to PAHs-associated adverse health effects. Little is known about the impact of PAHs on endocrine stress and inflammation in adolescence. We examined 393 Flemish adolescents (14-15 years) cross-sectionally, measured urinary concentrations of hydroxylated naphthalene, fluorene, phenanthrene and pyrene metabolites, and calculated the sum of all measured metabolites. We determined hair cortisol concentration (HCC) as endocrine stress biomarker, leucocyte counts and neutrophil-lymphocyte ratio (NLR) in peripheral blood as inflammatory biomarkers, and urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) concentration as oxidative stress biomarker. Exposure-response associations were analyzed by multiple regression, adjusted for a priori selected covariates. A doubling of 1-hydroxypyrene concentration was associated with a factor of 1.13 (95% CI: 1.03, 1.24) increase in HCC and a factor of 1.07 (95% CI: 1.02, 1.13) increase in 8-oxodG. Doublings of 2- and 3-hydroxyphenanthrene concentrations were associated with a factor of 1.08 (95% CI: 1.02, 1.14) and 1.06 (95% CI: 1.00, 1.12) increase in 8-oxodG, respectively. Doubling of 2-hydroxyphenanthrene and of the sum of 2- and 3-hydroxyfluorene was associated with, respectively, a factor of 1.08 (95% CI: 1.02, 1.14) and 1.06 (95% CI: 1.01, 1.13) increase in NLR. Our results indicate the glucocorticoid pathway as a potential target for PAH exposure in adolescents and suggest oxidative stress, endocrine stress, and inflammation in adolescence as underlying mechanisms and early markers for PAH-related adverse health effects.

Long-term residential exposure to air pollution is associated with hair cortisol concentration and differential leucocyte count in Flemish adolescent boys

BACKGROUND

Exposure to air pollution and traffic noise are associated with adverse health outcomes in adolescents. Chronic endocrine stress and systemic inflammation have been hypothesized to underlie the adverse health effects. Simultaneous assessment of inflammation and chronic endocrine stress in epidemiological studies is lacking. The aim of the study was to investigate biomarkers of chronic endocrine stress and inflammation in relation to long-term residential exposure to air pollution and traffic noise in adolescents.

METHODS

In Flemish adolescents (14-15 years), we determined hair cortisol concentration (HCC) as a chronic stress biomarker in 3-cm scalp-near hair sections (n = 395), and leucocyte and leucocyte subtype counts (neutrophils, monocytes, lymphocytes) as inflammatory biomarkers in peripheral blood (n = 385). Daily particulate matter (PM_2.5, PM₁₀), nitrogen dioxide (NO₂) and black carbon (BC) concentrations were modelled at the residential address and averaged over 3-month and 1-year periods prior to sampling. Residential traffic noise level was estimated and classified in 5 dB intervals. Sex-specific associations between residential exposures and effect biomarkers were studied using linear regression models, adjusted for a priori selected covariates.

RESULTS

In boys, HCC increased with a factor 1.30 (95% CI: 1.10, 1.54) for an increase in 1-year mean NO₂ from the 25th to 75th percentile (p75/p25), after adjustment for age, BMI, personal and neighborhood socioeconomic status. The corresponding estimate for PM₁₀ was 1.24 (95% CI: 1.02, 1.51). Total leucocyte count in boys, adjusted for the aforementioned covariates and recent health complaints, was positively associated with PM_2.5, PM₁₀, NO₂ and BC. In particular, the neutrophil count increased with a factor 1.11 (95% CI: 1.03, 1.19) for a (p75/p25)-factor increase in 1-year mean BC, corresponding estimates for PM_2.5, PM₁₀ and NO₂ were 1.10 (95% CI: 1.01, 1.19), 1.10 (95% CI: 1.01, 1.20) and 1.08 (95% CI: 1.00, 1.16). Lymphocyte count increased with a factor 1.05 (95% CI: 1.01, 1.10) for a (p75/p25)-factor increase in 1-year mean NO₂. Similar results were observed for 3-month mean exposures. Results were robust to adjustment for recent air pollution exposure. In girls, air pollutants were not associated with HCC or differential leucocyte count. Residential traffic noise level was not associated with HCC or leucocyte counts in boys nor girls.

CONCLUSIONS

Long-term residential exposure to air pollutants was positively associated with chronic endocrine stress and inflammation in adolescent boys, not in girls. This study may contribute to a better understanding of the early pathophysiological changes that may underlie adverse health effects of air pollution exposure in adolescents.

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.

Impact of environmental exposure to persistent organic pollutants on lung cancer risk

BACKGROUND

Recent studies suggest that high pre-diagnostic serum concentrations of persistent organic pollutants (POPs) might result in the development of cancers in the general population. However, the association between pre-diagnostic serum POP concentrations and lung cancer risk has not been studied. Here, we evaluated associations between low-dose environmental exposure to POPs and risk of lung cancer using pre-diagnostic serum samples in a case-cohort study based on a population-based prospective cohort.

METHODS

We conducted a case-cohort study based on the Korean National Cancer Center Community Cohort, from which we included 118 lung cancer cases and 252 controls. Serum concentrations of POPs were measured by high resolution gas chromatography/high-resolution mass spectrometry, and data were analyzed using multivariable Cox proportional-hazards regression models.

RESULTS

Risk of lung cancer increased per unit increase in the natural log-transformed concentrations of the sum of chlordane congeners, total PCBs, and all PCBs subgrouped by the number of chlorines or ortho- substituted chlorines on the molecules, except for tri/tetrachlorobiphenyls, in all models. Among individual POP analytes with a detection rate >80%, after Bonferroni adjustment, only trans-nonachlor was associated with lung cancer risk. In categorical models, risk of lung cancer was associated with serum concentration of chlordane (4th vs. 1st quartile, hazard ratio [95% confidence interval], 8.79 [2.77-27.97]). Dose-dependent relationships were also found between risk of lung cancer and serum concentrations of PCBs regardless of their degree of chlorination, substitution pattern, or binding affinity to receptors (total PCBs, P = 0.002; mid-chlorinated PCBs, P = 0.004; high-chlorinated PCBs, P < 0.001; non- and mono-ortho PCBs, P = 0.031; di-ortho PCBs, P = 0.003; PCBs with dioxin-like activity, P = 0.011; non-dioxin-like non-/mono-ortho PCBs, P = 0.060).

CONCLUSIONS

Serum concentrations of chlordane and PCBs are associated with risk of lung cancer in the general population, even decades after the ban on their production and use.

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.

A Systematic Review of Environmental Health Outcomes in Selected American Indian and Alaska Native Populations

BACKGROUND

Economic and social marginalization among American Indians and Alaska Natives (AI/ANs) results in higher chronic disease prevalence. Potential causal associations between toxic environmental exposures and adverse health outcomes within AI/AN communities are not well understood.

OBJECTIVES

This review examines epidemiological literature on exposure to toxicants and associated adverse health outcomes among AI/AN populations.

METHODS

PubMed, Embase, Cochrane, Environment Complete, Web of Science Plus, DART, and ToxLine were searched for English-language articles. The following data were extracted: lead author's last name, publication year, cohort name, study location, AI/AN tribe, study initiation and conclusion, sample size, primary characteristic, environmental exposure, health outcomes, risk estimates, and covariates.

RESULTS

About 31 articles on three types of environmental exposures met inclusion criteria: persistent organic pollutants (POPs), heavy metals, and open dumpsites. Of these, 17 addressed exposure to POPs, 10 heavy metal exposure, 2 exposure to both POPs and heavy metals, and 2 exposure to open dumpsites. Studies on the Mohawk Nation at Akwesasne; Yupik on St. Lawrence Island, Alaska; Navajo Nation; Gila River Indian Community; Cheyenne River Sioux; 197 Alaska Native villages; and 13 tribes in Arizona, Oklahoma, North Dakota, and South Dakota that participated in the Strong Heart Study support associations between toxicant exposure and various chronic conditions including cardiovascular conditions, reproductive abnormalities, cancer, autoimmune disorders, neurological deficits, and diabetes.

DISCUSSION

The complex interplay of environmental and social factors in disease etiology among AI/ANs is a product of externally imposed environmental exposures, systemic discrimination, and modifiable risk behaviors. The connection between environmental health disparities and adverse health outcomes indicates a need for further study.

Influence of polychlorinated biphenyls and organochlorine pesticides on the inflammatory milieu. A systematic review of in vitro, in vivo and epidemiological studies

BACKGROUND

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) are relevant families of persistent organic pollutants, which have been linked to several long-term adverse health effects. The mechanisms of action of these pollutants are still poorly understood. However, there are some evidences suggesting that inflammation might play a key role on their effects.

AIM

To systematically synthesize the published in vitro, in vivo and epidemiological data assessing the potential influence of exposure to OCPs and PCBs on the development of an inflammatory milieu.

METHODS

A systematic review of peer-reviewed original research papers published until 1st May 2019 was conducted, by using Medline, Web of Science and Scopus databases. A total of 39 articles met the inclusion criteria and were evaluated in this review.

RESULTS

The majority of the studies showed significant associations of PCB and OCP exposure with all inflammatory markers measured (n = 30). Some studies showed positive and negative associations (n = 7) and only two studies evidenced negative associations (n = 2). Most of the available evidences came from in vitro and in vivo studies (n = 31), with few epidemiological studies (n = 8).

CONCLUSIONS

We found consistent positive associations between exposure to PCBs and OCPs and the development of a pro-inflammatory milieu, with only few discrepancies. However, given the limited epidemiological evidence found, our results warrant further research in order to elucidate the real contribution of these pollutants on the inflammatory processes and subsequent diseases.

Intensive weight loss and cognition: The dynamics of persistent organic pollutants in adipose tissue can explain the unexpected results from the Action for Health in Diabetes (Look AHEAD) study

OBJECTIVE

The aim of this paper is to propose a new hypothesis for the role of lipophilic chemical mixtures stored in adipose tissue in the development of dementia. Specifically, we present how the dynamics of these chemicals can explain the unexpected findings from the Action for Health in Diabetes (Look AHEAD) study, which failed to show long-term benefits of intentional weight loss on cognition, despite substantial improvements in many known risk factors for dementia. Moreover, we discuss how the role of obesity in the risk of dementia can change depending on the dynamics of these chemicals in adipose tissue.

NEW HYPOTHESIS

Human adipose tissue is widely contaminated with various neurotoxic chemicals. Typical examples are persistent organic pollutants (POPs), strong lipophilic chemicals with long half-lives. Both unintentional and intentional weight loss increases the release of POPs from adipocytes into the circulation. As POPs in the blood can easily reach the brain, the intentional weight-loss group of the Look AHEAD study may have experienced an unappreciated and long-term disadvantage on their cognition. Additionally, POPs may be involved in the link between obesity and dementia, as dysfunctional hypertrophic adipocytes enhance the release of POPs from adipocytes to the circulation through uncontrolled lipolysis. In contrast, metabolically healthy obese people may have a low risk of dementia because the safe storage of POPs in adipose tissue would decrease the amount of POPs reaching the brain.

MAJOR CHALLENGES FOR THE HYPOTHESIS

In human studies, there are practical difficulties involved with measuring POPs in the blood, including high costs and complex assays. As the serum concentrations of POPs are continuously affected by weight loss and gain, prospective studies may require serial measurements of POPs. In in-vitro and in-vivo experimental studies, how to simulate the exposure dose, duration, and mixture patterns in humans would be critical.

LINKAGE TO OTHER MAJOR THEORIES

Even though POPs are direct neurotoxins at a high dosage, low-dose POPs are mitochondrial toxins. Therefore, chronic exposure to low-dose POPs is linked to known key interrelated mechanisms in the pathogenesis of dementia, such as mitochondrial dysfunction and neuroinflammation.

Experimental design of switchable solvent-based liquid phase microextraction for the accurate determination of etrimfos from water and food samples at trace levels by GC-MS

Presented in this study is a simple but efficient switchable polarity solvent microextraction strategy for etrimfos preconcentration from water and food samples for quantification by gas chromatography mass spectrometry. Repeatability of the extraction process and instrumental measurements were enhanced by using deuterated bisphenol A as internal standard. Significant parameters of the extraction method were fitted into an experimental design model to study the effects of parameters on extraction output, as well as mutual effects of combined parameters. The design model was formed with 51 experimented data obtained from the combination of sodium hydroxide volume, switchable solvent volume, and vortex period at three levels. The method was validated by applying optimum conditions attained from the model predictor. The detection limit was found to be 1.3 ng/mL and it corresponded to an enhancement factor of about 54 folds when compared to direct GC-MS measurement. Etrimfos was not detected in the water and food samples tested but the results (92-107%) obtained from spiked recovery experiments established that etrimfos when present in the selected matrices can be accurately and precisely quantified.

Dioxin-like PCB 126 Increases Systemic Inflammation and Accelerates Atherosclerosis in Lean LDL Receptor-Deficient Mice

Exposure to dioxins and related persistent organic pollutants likely contributes to cardiovascular disease (CVD) risk through multiple mechanisms including the induction of chronic inflammation. Epidemiological studies have shown that leaner individuals may be more susceptible to the detrimental effects of lipophilic toxicants because they lack large adipose tissue depots that can accumulate and sequester these pollutants. This phenomenon complicates efforts to study mechanisms of pollutant-accelerated atherosclerosis in experimental animal models where high-fat feeding and adipose expansion limit the bioavailability of lipophilic pollutants. Here, we investigated whether a model dioxin-like pollutant, PCB 126, could increase inflammation and accelerate atherosclerosis in Ldlr-/- mice fed a low-fat atherogenic diet. We fed Ldlr-/- mice the Clinton/Cybulsky diet (10% kcal fat, 0.15% cholesterol) and sacrificed mice at 8, 10, or 12 weeks postPCB (2 doses of 1 μmol/kg) or vehicle gavage. To characterize this novel model, we examined the effects of PCB 126 on markers of systemic inflammation, hematological indices, fatty livers, and atherosclerotic lesion size. Mice exposed to PCB 126 exhibited significantly increased plasma inflammatory cytokine levels, increased circulating biomarkers of CVD, altered platelet, and red blood cell counts, increased accumulation of hepatic fatty acids, and accelerated atherosclerotic lesion formation in the aortic root. PCB 126 also increased circulating neutrophils, monocytes, and macrophages as determined by flow cytometry analysis. Exposure to dioxin-like PCB 126 increases inflammation and accelerates atherosclerosis in mice. This low-fat atherogenic diet may provide a useful tool to study the mechanisms linking exposure to lipophilic pollutants to increased risk of CVD.

Health risk assessment of PAHs, PCBs and OCPs in atmospheric air of municipal solid waste landfill in Novi Sad, Serbia

The municipal solid waste landfill in Novi Sad, Serbia is in its operative status from early 1980s and represents potential significant source of environmental compartments pollution and the threat to human health as a result of undeveloped waste management practice. Residues of Polycyclic Aromatic Hydrocarbons (PAHs) and Persistent Organic Pollutants (POPs) as toxic, mutagenic, teratogenic and carcinogenic chemicals were investigated in ambient air of landfill site in Novi Sad. Passive air sampling technique was used for the purpose of ambient air sampling. Total risk to the human health is calculated as a sum of individual risks for each group of substances according to the recommended United States Environmental Protection Agency (US EPA) methodology. The overall results indicate that the landfill site in Novi Sad does not pose a relevant treat to human by inhalation of PAHs and POPs. The effect of low concentrations, non-monotonic dose response, synergistic and amplifying effects of chemical complexes must be highly respected while performing future health risk assessment.

Distribution of priority pollutants in the sediment of Vembanad Estuary, Peninsular India

The existence of Organochlorine pesticides (OCP's) and trace metals in tropical aquatic environments may cause a severe threat on account of their ubiquitous nature and long persistence. Monitoring of such contaminants has assumed immense significance in recent times. The present study assessed the OCP's and trace metal contamination in the surface sediments of the Vembanad wetland system in India. Various pollution indices were calculated to determine the sediment quality of the system and were also compared with uncontaminated sediments. Geo-accumulation index for Mercury varied from moderately to extremely polluted. The mean concentration of pesticide residues and trace metals in the sediments of Vembanad is found to be higher than in other aquatic systems in India. The situation demands further studies which focus on the potential bioaccumulation of OCPs and metals in the benthic food chain, succeeding biota and their impact on human consumption as the system supports a huge population for their livelihood. The Present study provides a baseline information on the spatial distribution of priority pollutants along with ecological risk status of Vembanad estuarine system (VES).

Liver Disease in a Residential Cohort With Elevated Polychlorinated Biphenyl Exposures

Endocrine and metabolism disrupting chemicals (EDCs/MDCs) have been associated with environmental liver diseases including toxicant-associated steatohepatitis (TASH). TASH has previously been characterized by hepatocellular necrosis, disrupted intermediary metabolism, and liver inflammation. Polychlorinated biphenyls (PCBs) are environmental EDCs/MDCs associated with the genesis and progression of steatohepatitis in animal models and human liver injury in epidemiology studies. The cross-sectional Anniston Community Health Survey (ACHS) investigates ortho-substituted PCB exposures and health effects near a former PCB manufacturing complex. The rates of obesity, diabetes, and dyslipidemia were previously determined to be high in ACHS. In this study, 738 ACHS participants were categorized by liver disease status using the serum cytokeratin 18 biomarker. Associations between PCB exposures and mechanistic biomarkers of intermediary metabolism, inflammation, and hepatocyte death were determined. The liver disease prevalence was high (60.2%), and 80.7% of these individuals were categorized as having TASH. Sex and race/ethnicity differences were noted. TASH was associated with increased exposures to specific PCB congeners, insulin resistance, dyslipidemia, proinflammatory cytokines, and liver necrosis. These findings are consistent with PCB-related steatohepatitis. ΣPCBs was inversely associated with insulin resistance/production, leptin, and hepatocyte apoptosis, while other adipocytokines were increased. This is possibly the largest environmental liver disease study applying mechanistic biomarkers ever performed and the most comprehensive analysis of PCBs and adipocytokines. It provides insight into the mechanisms of PCB-related endocrine and metabolic disruption in liver disease and diabetes. In the future, associations between additional exposures and liver disease biomarkers will be evaluated in the ACHS and follow-up ACHS-II studies.

Association between persistent endocrine-disrupting chemicals (PBDEs, OH-PBDEs, PCBs, and PFASs) and biomarkers of inflammation and cellular aging during pregnancy and postpartum

BACKGROUND

Endocrine-disrupting chemicals (EDCs) can target immune and metabolic pathways. However, few epidemiologic studies have examined the influence of EDCs on measures of inflammation and cellular aging during pregnancy and postpartum.

OBJECTIVE

We investigated associations between prenatal exposures to polybrominated diphenyl ethers (PBDEs), hydroxylated PBDE metabolites (OH-PBDEs), polychlorinated biphenyls (PCBs), and per- and polyfluorochemicals (PFASs) with repeated biomarker measurements of inflammation and cellular aging in women during pregnancy and the postpartum period.

METHODOLOGY

Overweight or obese pregnant women were recruited from the San Francisco Bay area (n = 103) during their first or second trimester of pregnancy. Blood samples were collected from participants at baseline (median 16 weeks gestation) and at three and nine months postpartum. Serum concentrations of PBDEs, OH-PBDEs, PCBs, and PFASs were measured at baseline. Inflammation biomarkers (interleukin 6 [IL-6], interleukin 10 [IL-10], and tumor necrosis factor [TNF-α]) and leukocyte telomere length (LTL), a biomarker of cellular aging, were measured at all three time points. Associations between serum chemical concentrations and repeated measures of IL-6, IL-10, TNF-α, and LTL were examined using linear mixed models. We also examined the potential for effect modification by time (visit) and obesity.

RESULTS

In adjusted models, we observed positive relationships between PBDEs and pro-inflammatory cytokines (IL-6 and TNF-α). A doubling in ∑PBDEs was associated with a 15.26% (95% CI 1.24, 31.22) and 3.74% (95% CI -0.19, 7.82) increase in IL-6 and TNF-α, respectively. Positive associations were also observed for PFASs and IL-6. A two-fold increase in ∑PFASs was associated with a 20.87% (95% CI 3.46, 41.22) increase in IL-6. 5-OHBDE-47 was inversely associated with anti-inflammatory cytokine IL-10. Some EDC-outcome associations, including those of PBDEs with TNF-α, were stronger during pregnancy (compared to three or nine months postpartum) and among obese (compared to overweight) women (p-interaction <0.05).

CONCLUSIONS

These findings suggest that exposure to specific EDCs is associated with increased inflammation among women during pregnancy and the postpartum period. Future studies should replicate these findings in additional study populations and examine the implications of these associations for maternal and child health.

Persistent organic pollutants and risk of type 2 diabetes: A prospective investigation among middle-aged women in Nurses' Health Study II

BACKGROUND

Exposure to persistent organic pollutants (POPs) may predispose to the development of type 2 diabetes (T2D), but prospective human evidence is scarce.

OBJECTIVES

We investigated the association between plasma-POP concentrations in the late 1990s and incident T2D over 11 years of follow-up in the Nurses' Health Study II.

DISCUSSION

Three organochlorine pesticides and 20 polychlorinated biphenyls (PCBs) were measured in banked plasma from 793 case-control pairs of T2D. In a multiviarate-adjusted model, T2D ORs (95%CIs) comparing extreme POP tertiles (high vs. low) were 1.67 (1.24, 2.23; Ptrend < 0.001) for hexachlorobenzene (HCB), 3.62 (2.57, 5.11; Ptrend < 0.001) for β-hexachlorocyclohexane (β-HCH), 1.55 (1.13, 2.13; Ptrend = 0.05) for p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), and 1.95 (1.42, 2.69; Ptrend < 0.001) for total dioxin-like PCBs (DL-PCBs) which included 5 mono-ortho congeners, PCB-105, 118, 156, 157, and 167. Adjustment for previous weight change and body mass index (BMI) at blood draw attenuated these associations, but that for DL-PCBs remained (OR[95% CI] = 1.78[1.14, 2.76]; Ptrend = 0.006). Age, breastfeeding history, previous weight change and BMI at blood draw were significant predictors of plasma POP concentrations. In addition, we found significant interactions of POPs and weight change before blood draw on T2D risk. ORs (95%CIs) of T2D comparing extreme (high vs. low) POP groups were 2.00 (1.02, 3.92; Ptrend = 0.01) for HCB, 2.69 (1.34, 5.40; Ptrend < 0.001) for β-HCH, and 2.41 (1.22, 4.77; Ptrend < 0.001) for DL-PCBs in the lowest weight gain group, whereas these values were 1.29 (0.73, 2.28; Ptrend = 0.46; Pinteraction = 0.04) for HCB, 1.41 (0.77, 2.60; Ptrend = 0.24; Pinteraction = 0.003) for β-HCH, and 0.90 (0.50, 1.63; Ptrend = 0.61; Pinteraction = 0.01) for DL-PCBs in the highest weight-gain group.

CONCLUSIONS

Our findings suggest that elevated POP exposure may have diabetogenic potential. These data also highlight the impact of lifestyle factors, especially history of weight gain, on circulating POP concentrations and their associations with subsequent T2D risk.

The influence of persistent organic pollutants in the traditional Inuit diet on markers of inflammation

Concentrations of persistent organic pollutants (POPs) are high in Inuit living predominately on the traditional marine diet. Adverse effects of POPs include disruption of the immune system and cardiovascular diseases that are frequent in Greenland Inuit. We aimed to assess the association between exposure to POPs from the marine diet and inflammation, taking into account other factors such as vitamin D. We invited Inuit and non-Inuit living in settlements or the town in rural East Greenland or in the capital city Nuuk. Participants completed a food frequency questionnaire and donated a blood sample for measurement of the two markers of inflammation YKL-40 and hsCRP, 25-hydroxy-vitamin D, eleven organochlorine pesticides (OCPs), fourteen polychlorinated biphenyls (PCBs), one polybrominated biphenyl, and nine polybrominated diphenyl ethers (PBDEs) adjusted to the serum lipid content. Participants were 50 through 69 years old, living in settlements, town or city (n = 151/173/211; 95% participation rate). ΣOCP, ΣPCB and ΣPBDE serum levels were higher in Inuit than in non-Inuit (p<0.001/ p<0.001/ p<0.001), in older individuals (p<0.001/p<0.001/p = 0.002) and in participants with the highest intake of Greenlandic food items (p<0.001/p<0.001/p<0.001). Both YKL-40 and hsCRP serum levels were higher in Inuit compared to non-Inuit (p<0.001/p = 0.001), and increased with age (p<0.001/p = 0.001) and with the intake of Greenlandic food items (p<0.001/p = 0.002). Multivariate analysis conformed to a marked influence on both YKL-40 and hsCRP by ΣOCP (p<0.001/p<0.001) and ΣPCBs (p<0.001/p = 0.001) after adjusting for age, BMI, vitamin D, alcohol and smoking. POP levels were associated with the intake of the traditional Inuit diet and with markers of inflammation. This supports a pro-inflammatory role of POPs to promote chronic diseases common to populations in Greenland. These data inform guidelines on 'the Arctic dilemma' and encourage follow-up on the ageing Arctic populations.

Biomonitoring of persistent organic pollutants (POPs) in child populations living near contaminated sites in Mexico

The aim of this study was to conduct a POP biomonitoring programme for children in high-risk areas. We evaluated 247 serum samples from children between the ages of 6 and 12years old from two zones in Mexico: (1) indigenous zones, which included Cuatlamayan (CUA), Tocoy (TOC), and Santa Maria Picula (SAM); and (2) industrial zones, which included Tercera Chica (TC), Industrial San Luis (IND) and Rincon de San Jose (SJR); Mundo Nuevo (MN); and Alpuyeca (ALP). Our results showed that α-endosulfan was similar to CUA, TOC, SAM, TC and MN (178.6-306.9ng/g lipid). β-Endosulfan levels were higher in ALP (901.5ng/g lipid), followed by CUA (139.9ng/g lipid) and TOC, SAM, TC and MN, which had similar levels (55.4-64.5ng/g lipid). For endosulfan sulfate, the ALP community had the highest concentration levels (1096.4ng/g lipid), whereas CUA and TOC (212.3 and 289ng/g lipid, respectively) had concentrations similar to those found in SAM and TC (99.5 and 119.1ng/g lipid, respectively). DDE levels were found in malaria-endemic areas of SAM, CUA and TOC (1782.2, 1358.3 and 57.0ng/g lipid), followed by MN (35.1ng/g lipid). HCB concentration levels were found to be higher in MN and SJR (691.8 and 575.4ng/g lipid, respectively), followed by CUA and TC (363.9 and 269.1ng/g lipid, respectively), with levels similar to those found in TOC and SAM (191.8 and 181.9ng/g lipid, respectively). Finally, PCB 101 concentration levels were found to be the highest in ALP (1032.7ng/g lipid), followed by similar levels of SJR and IND (567.5 and 327.3ng/g lipid, respectively) and TC and MN, with 109.1 and 144.5ng/g lipid, respectively. The evidence provided by this exploratory study indicates that the evaluation of the health risks posed to children living in contaminated areas is a high priority health issue.

Alterations in high-density lipoprotein proteome and function associated with persistent organic pollutants

There is a growing body of evidence that persistent organic pollutants (POPs) may increase the risk for cardiovascular disease (CVD), but the mechanisms remain unclear. High-density lipoprotein (HDL) acts protective against CVD by different processes, and we have earlier found that HDL from subjects with CVD contains higher levels of POPs than healthy controls. In the present study, we have expanded analyses on the same individuals living in a contaminated community and investigated the relationship between the HDL POP levels and protein composition/function. HDL from 17 subjects was isolated by ultracentrifugation. HDL protein composition, using nanoliquid chromatography tandem mass spectrometry, and antioxidant activity were analyzed. The associations of 16 POPs, including polychlorinated biphenyls (PCBs) and organochlorine pesticides, with HDL proteins/functions were investigated by partial least square and multiple linear regression analysis. Proteomic analyses identified 118 HDL proteins, of which ten were significantly (p<0.05) and positively associated with the combined level of POPs or with highly chlorinated PCB congeners. Among these, cholesteryl ester transfer protein and phospholipid transfer protein, as well as the inflammatory marker serum amyloid A, were found. The serum paraoxonase/arylesterase 1 activity was inversely associated with POPs. Pathway analysis demonstrated that up-regulated proteins were associated with biological processes involving lipoprotein metabolism, while down-regulated proteins were associated with processes such as negative regulation of proteinases, acute phase response, platelet degranulation, and complement activation. These results indicate an association between POP levels, especially highly chlorinated PCBs, and HDL protein alterations that may result in a less functional particle. Further studies are needed to determine causality and the importance of other environmental factors. Nevertheless, this study provides a first insight into a possible link between exposure to POPs and risk of CVD.

Endosulfan induces autophagy and endothelial dysfunction via the AMPK/mTOR signaling pathway triggered by oxidative stress

Cardiovascular diseases is related to environmental pollution. Endosulfan is an organochlorine pesticide and its toxicity has been reported. However, the relationship between oxidative stress and autophagy induced by endosulfan and its underlying mechanism remain confusing. In this study, human umbilical vein endothelial cells (HUVECs) were chosen to explore the toxicity mechanism and were treated with 0, 1, 6, 12 μg/mL^-1 endosulfan for 24 h, respectively. The present results showed that autophagy could be induced by endosulfan, which was verified by the monodansylcadaverine staining, autophagic ultrastructural observation, and LC3-I/LC3-II conversion. In addition, the levels of adenosine triphosphate (ATP), the mitochondria membrane potential (MMP) were significantly decreased in a dose-dependent way. The expression of proinflammatory cytokines (tumor necrosis factor α, interleukin-1β, and interleukin-6) were significantly elevated, and the index of endothelial function such as monocyte chemotactic protein 1 (MCP-1), intercellular cell adhesion molecule-1 (ICAM-1) increased. Moreover, endosulfan had an activation effect on the 5'AMP-activated protein kinase (AMPK)/rapamycin (mTOR) signaling pathway. Our findings demonstrated that endosulfan could induce oxidative stress and mitochondria injury, activate autophagy, induce inflammatory response, and eventually lead to endothelial dysfunction via the AMPK/mTOR pathway. This indicates that exposure to endosulfan is a potential risk factor for cardiovascular diseases.

Serum polybrominated diphenyl ether (PBDE) concentrations in relation to biomarkers of oxidative stress and inflammation: The National Health and Nutrition Examination Survey 2003-2004

Exposure to polybrominated diphenyl ethers (PBDEs) has been associated with various adverse health outcomes related to liver, neural and endocrine systems. Some of these may be the result of PBDE-induced oxidative stress or inflammation, but these associations have been explored minimally in humans. In the present study we examined the relationship between PBDE concentrations and biomarkers of oxidative stress and inflammation measured in blood samples among a representative US sample from the National Health and Nutrition Examination Survey. Oxidative stress biomarkers showed no significant associations with PBDEs in adjusted regression models. For inflammation biomarkers, we observed small but statistically significant positive associations between BDE-153 and alkaline phosphatase (percent change with an interquartile range [IQR] increase in BDE-153=0.82, 95% confidence interval [CI]=0.01, 1.65) and absolute neutrophil count (percent change with IQR increase in BDE-153=0.53%, 95% CI=0.03, 1.04). Associations with other PBDE congeners and inflammation markers were generally positive but did not reach statistical significance. These results are consistent with human research of oxidative stress and inflammation in response to PBDE congeners and mixtures, and support previous reports of inflammation in response to PBDE treatment in animal and in vitro studies. More detailed toxicological and epidemiologic research in humans is needed to confirm the present results, and to determine the potential clinical and public health significance of these findings.

Contribution of Persistent Organic Pollutant Exposure to the Adipose Tissue Oxidative Microenvironment in an Adult Cohort: A Multipollutant Approach

Despite growing in vitro and in vivo evidence of the putative role of persistent organic pollutants (POPs) in the induction of oxidative damage in cell structures, this issue has been poorly addressed from an epidemiologic perspective. The aim of this study was to explore associations between adipose tissue POP concentrations and the in situ oxidative microenvironment. A cross-sectional study was conducted in a subsample (n = 271) of a previously established cohort, quantifying levels of eight POPs and four groups of oxidative stress biomarkers in adipose tissue. Associations were explored using multivariate linear regression analyses adjusted for potential confounders. We assessed the combined effect of POPs on oxidative stress/glutathione system biomarkers using weighted quantile sum regression (WQS). Increased concentrations of p,p'-DDE, HCB, β-HCH, dicofol, and PCBs (congeners -138, -153, and -180) were predominantly associated with higher lipid peroxidation (TBARS) [exp(β) = 1.09-1.78, p < 0.01-0.04)] and SOD activity [exp(β) = 1.13-1.48, p < 0.01-0.05)] levels. However, only a few associations were observed with glutathione system biomarkers, e.g., PCB-180 with total glutathione [exp(β) = 1.98, p = 0.03]. The WQS index was found to be positively associated with SOD activity, and PCB-138, PCB-180, and β-HCH were the main contributors to the index. Likewise, the WQS index was positively associated with TBARS levels, with the three PCBs acting as the main contributors. This is the first epidemiological evidence of the putative disruption by POPs of the adipose tissue oxidative microenvironment. Our results indicate that POP exposure may enhance alternative pathways to the glutathione detoxification route, which might result in tissue damage. Further research is warranted to fully elucidate the potential health implications.

Effects of the Dietary Detoxification Program on Serum γ-glutamyltransferase, Anthropometric Data and Metabolic Biomarkers in Adults

Background

Persistent Organic Pollutants (POPs) are well-known environmental contaminants which are associated with chronic diseases. As foods are the major sources of human exposure to toxic pollutants, we developed an integrated dietary and education program to eliminate the chemical toxin throughout the human body. The present study evaluated effects of the dietary detoxification program on serum γ-glutamyltransferase (GGT), anthropometric data and metabolic biomarkers in adults.

Methods

Single-armed, pre-post study was conducted from June 2013 to June 2015 at a health examination center and a public health center in Seoul, Korea. Sixty eight subjects (mean age of 52.4 years) were recruited. Subjects participated 20 hours’ dietary education sessions. On-line coaching with SNS was performed to enhance participants’ proper protocol compliance. Physical and laboratory examinations were assessed at week 0 and 3.

Results

Changes of the serum GGT were correlated with reductions of the body fat percentage (r = .379, p = .001), body fat mass (r = .435, p = .000) and fasting blood glucose (r = .423, p = .000). Serum GGT, weight, body fat percentage, body fat mass, waist circumference, LDL-cholesterol, HDL-cholesterol, triglyceride, total cholesterol, and blood pressure of all participants were reduced with statistical significance in 3 weeks. In metabolic syndrome group, total cholesterol (p = .049), fasting blood glucose (p = .002), and systolic blood pressure (p = .001) were significantly reduced comparison to non-metabolic syndrome group.

Conclusion

This dietary detoxification program might decrease serum GGT which indicated the overall toxic burden in the body. Anthropometric data and metabolic biomarkers were improved. The integrated dietary and education detoxification program seemed to be a protective intervention for elimination of toxicants from the body.

Relationship of polychlorinated biphenyls (PCBs) with parasitism, iron homeostasis, and other health outcomes: Results from a cross-sectional study on recently arrived African immigrants

Polychlorinated biphenyls (PCBs) are toxic and persistent chemicals produced between 1930s and 1980s, which accumulate in humans and wildlife. Although a decreasing trend of PCB levels in humans has been described in developed countries, mainly as a consequence of strict regulations and remediation plans, an inverse trend has been recently reported in people from developing countries. We had the opportunity of sampling a series of African immigrants recently arrived to the Spanish archipelago of the Canary Islands, in which high levels of PCBs have been described, and we studied the relationships between their level of contamination and health status. A total of 570 subjects who underwent a complete medical examination and a face-to-face interview were recruited for this study. Hematological and biochemical parameters (blood and urine) were determined in all participants. Serology for the diagnostic of infectious diseases was also performed, and direct identification of parasites was performed in feces, urine or blood samples when appropriate. It is remarkable that up to 26.0% of the population had intestinal parasites, and we found an inverse relationship between PCB levels and parasitism and parasitic diseases: median values of PCBs were lower in parasitized subjects than in subjects without parasites in stool (237.6ng/g fat vs. 154.4ng/g fat for marker PCBs, p=0.015) and median values of dioxin-like PCBs were lower in subjects carrying pathogen parasites than among subjects showing non-pathogen parasites in stool (0.0 ng/g fat vs. 13.1ng/g fat, respectively; p=0.001). Although this inverse association had been described in some vertebrates this is the first study reporting such an association in humans. Furthermore, it has been also recently described that PCBs may disrupt iron metabolism, and we found a direct relationship between serum iron and total PCBs burden (r=0.231, p=0.025), suggesting that PCBs, although at subclinical level, could play a role on iron homeostasis. Although the role of PCBs in parasitism and in the iron metabolism needs future research, our findings may help to understand the adverse health outcomes associated to environmental exposure to PCBs and they might be used in exposed populations as indicators of subtle effects due to environmental insult.

A Systems Biology Approach Reveals Converging Molecular Mechanisms that Link Different POPs to Common Metabolic Diseases

BACKGROUND

A number of epidemiological studies have identified statistical associations between persistent organic pollutants (POPs) and metabolic diseases, but testable hypotheses regarding underlying molecular mechanisms to explain these linkages have not been published.

OBJECTIVES

We assessed the underlying mechanisms of POPs that have been associated with metabolic diseases; three well-known POPs [2,3,7,8-tetrachlorodibenzodioxin (TCDD), 2,2´,4,4´,5,5´-hexachlorobiphenyl (PCB 153), and 4,4´-dichlorodiphenyldichloroethylene (p,p´-DDE)] were studied. We used advanced database search tools to delineate testable hypotheses and to guide laboratory-based research studies into underlying mechanisms by which this POP mixture could produce or exacerbate metabolic diseases.

METHODS

For our searches, we used proprietary systems biology software (MetaCore™/MetaDrug™) to conduct advanced search queries for the underlying interactions database, followed by directional network construction to identify common mechanisms for these POPs within two or fewer interaction steps downstream of their primary targets. These common downstream pathways belong to various cytokine and chemokine families with experimentally well-documented causal associations with type 2 diabetes.

CONCLUSIONS

Our systems biology approach allowed identification of converging pathways leading to activation of common downstream targets. To our knowledge, this is the first study to propose an integrated global set of step-by-step molecular mechanisms for a combination of three common POPs using a systems biology approach, which may link POP exposure to diseases. Experimental evaluation of the proposed pathways may lead to development of predictive biomarkers of the effects of POPs, which could translate into disease prevention and effective clinical treatment strategies.

CITATION

Ruiz P, Perlina A, Mumtaz M, Fowler BA. 2016. A systems biology approach reveals converging molecular mechanisms that link different POPs to common metabolic diseases. Environ Health Perspect 124:1034-1041; http://dx.doi.org/10.1289/ehp.1510308.

Comparative Toxicological Study between Exposed and Non-Exposed Farmers to Organophosphorus Pesticides

Objective

The purpose of this work was to compare DNA damage, acetylcholinesterase (AChE) activity, inflammatory markers and clinical symptoms in farmers exposed to organophosphorus pesticides to individuals that had no pesticide exposure.

Materials and Methods

We conducted a cross-sectional survey with a total of 134 people. The subject group consisted of 67 farmers who were exposed to organophosphorus pesticides. The control group consisted of 67 people without any contact with pesticides matched with the subject group in terms of age, gender, and didactics. Oxidative DNA damage, the activities of AChE, interleukin-6 (IL6), IL10 and C-reactive protein (CRP) in serum were measured and clinical examinations conducted in order to register all clinical signs.

Results

Compared with the control group, substantial gains were observed in the farmers’ levels of oxidative DNA damage, IL10 and CRP. There was significantly less AChE activity in farmers exposed to organophosphorus pesticides. The levels of IL6 in both groups did not significantly differ.

Conclusion

The outcomes show that exposure to organophosphorus pesticides may cause DNA oxidative damage, inhibit AChE activity and increase the serum levels of inflammatory markers. Using biological materials instead of chemical pesticides and encouraging the use of safety equipment by farmers are some solutions to the adverse effects of exposure to organophosphorous pesticides.

2,3',4,4',5-Pentachlorobiphenyl Induces Inflammatory Responses in the Thyroid Through JNK and Aryl Hydrocarbon Receptor-Mediated Pathway

Polychlorinated biphenyls (PCBs) are durable and widely distributed environmental contaminants that can compromise the normal functions of multiple organs and systems; one important mechanism is the induction of inflammatory disorders. In this study, we explored the influences of 2,3',4,4',5-pentachlorobiphenyl (PCB118) on inflammatory responses and its underlying mechanisms in the thyroid. Wistar rats were administered PCB118 intraperitoneally at 0, 10, 100, and 1000 μg/kg/d, 5 days a week for 13 weeks; rat thyroid FRTL-5 cells were treated with PCB118 (0, 0.25, 2.5, and 25 nM) for indicated time. Results revealed that PCB118 promoted the generation of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) in a time- and dose-related manner and decreased sodium/iodide symporter (NIS) protein expression. Moreover, stimulation with PCB118 resulted in the upregulation of the aryl hydrocarbon receptor (AhR)-responsive gene cytochrome P450 1A1 in FRTL-5 cells; whereas pretreatment with the AhR inhibitor α-naphthoflavone or AhR small interfering RNA (siRNA) suppressed AhR, CYP1A1, IL-6, and ICAM-1 and restored NIS expression. In vivo and in vitro studies also suggested that the c-Jun N-terminal kinase (JNK) pathway was activated on PCB118 exposure, and the experiments using siRNA for JNK partially blocked PCB118-induced upregulation of IL-6 and ICAM-1 and downregulation of NIS. Altogether, PCB118 stimulates production of IL-6, TNF-α, and ICAM-1 in the thyroid through AhR and JNK activations and subsequently interferes with NIS expression, resulting in the disruption of thyroid structure and function.

Persistent organic pollutants and biomarkers of diabetes risk in a cohort of Great Lakes sport caught fish consumers

BACKGROUND

Exposure to persistent organic pollutants (POPs) is associated with increased diabetes risk, although the mechanism of action is not well delineated.

METHODS

We investigated established diabetes biomarkers that could implicate potential mechanistic pathways, including C-reactive protein (CRP), a marker of systemic inflammation; gamma glutamyl transferase (GGT), a liver enzyme associated with oxidative stress; and adiponectin, an adipokine modulating glucose regulation and fatty acid oxidation. These biomarkers as well as hemoglobin A1c (HA1c), and POPs [polychlorinated biphenyls (PCBs), p,p-dichlorodiphenyldichloroethylene (DDE) and polybrominated diphenyl ethers (PBDEs)] were measured in a cohort of Great Lakes sport caught fish (GLSCF) consumers. We examined associations of POPs and fish consumption with HA1c and incident diabetes, and evaluated mediation and moderation by the diabetes biomarkers.

RESULTS

Odds of incident diabetes were elevated with exposure to DDE and PCBs. DDE and PCB 118 were positively, and fish meals were inversely, associated with HA1c. CRP was inversely associated with saltwater and total fish meals, particularly in persons with higher adiposity, but did not mediate the associations of fish meals with HA1c. There were few associations of POPs with adiponectin, CRP and GGT, with the exception of positive associations of PCB 118 with GGT, PBDEs with GGT in older persons, and PBDEs with adiponectin. Adiponectin, CRP and GGT did not mediate associations of DDE and PCBs with HA1c or incident diabetes. However, the association of DDE with HA1c was stronger in persons with higher CRP, GGT and BMI, and lower adiponectin, while the association of PCB 118 with HA1c was stronger in persons with higher GGT.

CONCLUSIONS

These findings suggest that adiponectin, CRP and GGT did not mediate effects of POPs on diabetes or HA1c. However, POPs may have stronger effects on blood glucose in persons at higher risk for diabetes.