Este trabalho visou determinar a ocorrência de PCBs e pesticidas organoclorados em peixes da região da Baixada Santista. Foram feitas coletas de peixes das espécies Paralonchurus brasiliensis, Trichiurus lepturus e Cathorops spixii em três diferentes localidades. Depois de sub-amostradas em músculo, fígado, brânquias e gônadas, as amostras foram extraídas em aparelhagem Soxhlet e analisadas por técnicas cromatográficas. O DDT apresentou-se em 66 % das amostras com concentrações variando entre 18,92 e 690,29 ng.g-1 lipídio. O HCH foi detectado em 34 % das amostras com concentração variando de 8,92 a 103,04 ng.g-1 lipídio, sendo a região da Ilha da Moela a mais afetada por esse composto. O Mirex apresentou-se em 28 % das amostras e alcançou valores entre 5,90 e 222,17 ng.g-1 lipídio. O HCB foi o inseticida menos encontrado neste trabalho, com 16 % das amostras apresentando contaminação variando de 7,75 a 94,47 ng.g-1 lipídio, todas na espécie bentônica Cathorops spixii. Os PCBs estiveram presentes em todas as localidades analisadas, sendo os congêneres com número entre quatro e sete cloros os que mais bioacumularam. A bioacumulação de organoclorados nos diferentes tecidos não ocorreu de forma igual para todas as espécies analisadas. Aparentemente, a maior contribuição para poluição orgânica dos peixes da Baía de Santos e áreas próximas origina-se do estuário ou do emissário. / Industrial and sewers pollution have being affected seriously the region of Baixada Santista, in the central shore of São Paulo State, Brazil. The great development of Cubatão city caused diverse health problems in the 70´s and 80´s. This present study shows organochlorine distribution in fishes collected in the Santos Bay and Moela Island. Paralonchurus brasiliensis, Trichiurs lepturus and Cathorops spixii had been captured in three different locations, sub-sampled in muscle, liver, gills and gonads. The samples was extracted in Soxhlet apparatus and analyzed by chromatographic techniques. DDT was presented in 66 % of the samples and concentrations varied between 18,92 and 690,29 ng.g-1 lipid. The HCH was detected in 34 % of the samples with concentration ranged from 8,92 to 103,04 ng.g-1 lipid. The region of the Moela Island was the most affected region by HCH pollution. The Mirex was presented in 28 % of the samples and reached values between 5,90 and 222,17 ng.g-1 lipid mostly in the Moela Island and Santos Bay. The HCB was the least found insecticide in this work and occurred in 16 % of the samples that presented concentration that varied from 7,75 to 94,47 ng.g-1 lipid. The muscles and gills of the bentic specie Cathorops spixii appeared to be an important tissues to accumulation of HCB. The PCBs were present in every studied locations. Congeners with number of chlorine between four and seven were the most bioacumulated ones. The bioaccumulation of different tissues did not occurred in the same way. Apparently, the greatest contribution for organic pollution to the fishes of Santos Bay and surrounding areas originates from the estuary or the emissary.

Exposure to environmental pollutants poses numerous risk factors for human health, including increasing incidence of cardiovascular disease and diabetes. Persistent organic pollutants, such as polychlorinated biphenyls (PCBs) have been strongly linked to the development of these chronic inflammatory diseases and the primary route of exposure is through consumption of contaminated food products. Thus, the gastrointestinal tract is susceptible to the greatest levels of these pollutants and is an important facet to study. The first two hypotheses of this dissertation tested that exposure to PCBs disrupts gut microbiota directly (in vitro) and within a whole body system. PCB exposure disrupted microbial metabolism and production of metabolites (i.e. short chain fatty acids) in vitro. These disruptions in microbial populations were consistent in our mouse model of cardiometabolic disease, where we observed reductions in microbial diversity, an increase in the putative pro-inflammatory ratio of Firmicutes to Bacteroidetes, and reductions in beneficial microbial populations in exposed mice. Furthermore, observed greater inflammation was observed both within the intestines and peripherally in PCB exposed mice as well as disruptions in circulating markers associated with glucose homeostasis. Nutritional interventions high in prebiotic dietary fiber such as inulin may be able to attenuate the toxic effects of pollutant exposure. To test the hypothesis that consumption of the prebiotic inulin can decrease PCB-induced disruption in gut microbial and metabolic homeostasis, LDLr-\- mice were fed a diet containing inulin and exposed to PCB 126. Mice fed an inulin-containing diet and exposed to PCBs exhibited improved glucose tolerance, lower hepatic inflammation and steatosis, and distinct differences in gut microbial populations. Overall, these data suggests that nutritional intervention, specifically prebiotic consumption, may reduce pollutant-induced disease risk.

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that are known to elicit adverse health effects including skin toxicity and cancer to animals and humans. 4-Monochlorobiphenyl (PCB3), a low-chlorinated airborne PCB conger is present in human blood and the environment. 1-(4-Chlorophenyl)-benzo-2,5-quinone (4-ClBQ), a quinone metabolite of PCB3, has been shown to induce oxidative stress and toxicity in human mammary and prostate epithelial cells. These studies were designed to investigate and characterize the cellular responses to 4-ClBQ in HaCaT human skin keratinocytes. We found that 4-ClBQ treatment increased cellular reactive oxygen species (ROS) production, inhibited cell proliferation, and induced toxicity in HaCaT cells. Results from a Human Antioxidant Mechanism PCR array and quantitative RT-PCR assay showed that the mRNA levels of antioxidant gene selenoprotein P (sepp1) and catalase were significantly downregulated by the treatment, which correlated with evident decreases in their protein levels and catalase enzymatic activity. Pharmacological (sodium selenite supplementation) and molecular (sepp1overexpression) manipulation of SEPP1 expression significantly suppressed 4-ClBQ induced oxidative stress and toxicity. Additional results demonstrated that decreased catalase expression was associated with an inhibition in transcriptional coactivator peroxisome proliferator activated receptor Γ coactivator 1α (PGC-1α) expression. Overexpression of pgc-1α restored catalase expression and activity and consequently protected HaCaT cells from 4-ClBQ induced oxidative stress and toxicity. Furthermore, results from metabolic flux analysis using Seahorse XF96 Analyzer showed that 4-ClBQ treatment increased extracellular acidification rate, proton production rate, and oxygen consumption rate, which were associated with increases in glucose uptake and in the expression of glucose metabolism regulatory gene hexokinase 2, pyruvate kinase M2, and glucose-6-phosphate dehydrogenase (G6PD). G6PD is the rate-limiting enzyme of the pentose phosphate pathway. The enhanced expression of G6PD correlated with an increase in cellular glutathione content; and inhibition of G6PD activity sensitized HaCaT cells to 4-ClBQ induced toxicity, suggesting that the protective function of the pentose phosphate pathway is active in 4-ClBQ treated cells. Interestingly, we also found that 4-ClBQ selectively and significantly decreased mitochondrial complex II subunits C (sdhc) and D (sdhd) mRNA expression and subsequently reduced complex II activity leading to metabolic oxidative stress and toxicity, which were significantly suppressed by overexpressing sdhc and sdhd in HaCaT cells. Taken together, findings from this project demonstrate that 4-ClBQ treatment increases ROS production through perturbing cellular metabolism and mitochondrial function and decreases antioxidant capacity by inhibiting SEPP1 and catalase expression in HaCaT cells. This imbalance due to increased mitochondrial prooxidant production and decreased antioxidant capacity leads to oxidative stress and toxicity. Importantly, antioxidant supplementation could abrogate 4-ClBQ induced toxicity, suggesting that antioxidants, especially nutrient-based manipulation of selenoproteins could be promising countermeasures for PCB induced adverse health effects in humans.

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that have been associated with a myriad of negative human health effects. These man-made compounds were used throughout most of the 20th century and although their intentional production has since been banned and their use limited to closed systems, their prevalence in the environment remains a factor in disease states for exposed populations. The worldwide levels of PCBs has been declining, however, there is evidence for renewed sources of these compounds. The presence of PCBs with lower numbers of chlorine atoms (LC-PCBs) have been verified as unintentional byproducts in paints and pigments, the decomposition of PCB waste, or the recycling or disposal attempts of PCB-laden materials. While exposure to the higher chlorinated congeners (HC-PCBs) is often attributed to the consumption of contaminated water or fatty animal meat, a significant route of exposure to the airborne LC-PCBs is through inhalation. These semi-volatile compounds have been detected in high quantities in both indoor and outdoor air in urban and rural communities, and their presence is pronounced in older buildings (e.g., homes and schools). When compared to HC-PCBs, LC-PCBs are more highly susceptible to metabolic transformations, and recently their sulfated metabolites have gained much interest. Although the sulfation of xenobiotics often is considered a route for their removal from the body, a previous study of Sprague-Dawley rats treated with 4-chlorobiphenyl (PCB 3) resulted in the substantial formation of sulfated metabolites (i.e., hydroxylation followed by sulfation of the LC-PCB). This metabolic route accounted for more than half of the treatment dose. Furthermore, LC-PCB sulfates have been shown to bind to the human serum protein, transthyretin, in vitro. Of the health effects associated with PCB exposure, neurotoxicity has been well established through various laboratory and epidemiological studies. It is proposed that the dopaminergic system lies at the core of the observed cognitive, motor, and intellectual dysfunction observed in exposed populations, especially in children exposed perinatally. Interestingly, PCB exposure has been linked to Parkinson's disease (PD) etiology, which is marked by a substantial loss of dopaminergic neurons. This thesis describes studies on the binding of selected LC-PCBs and their hydroxylated and sulfated metabolites to human serum albumin (HSA), the most abundant protein in human serum. The displacement of fluorescent probes, selective for the two major drug binding sites of HSA, indicates that LC-PCB sulfates generally bind to HSA with such affinity that is equal to or greater than that for the LC-PCBs or OH-LC-PCBs This work also included a study of the selective toxicity of these compounds to dopaminergic neuronal cells. The selective toxicity of these compounds was studied in a series of immortalized cell lines (i.e., two neuronal cell lines: the rat midbrain-derived N27 cell line, the human neuroblastoma-derived SH-SY5Y cell line, and the human liver-derived HepG2 cell line). The assessment of toxicity by MTT reduction and LDH release in these cellular models indicated that hydroxylated and sulfated metabolites of LC-PCBs exhibited toxicity that was selective to neuronal cells and, in most cases, selective for the dopaminergic neuronal cells. Furthermore, HPLC analysis of the distribution of the compounds from the extracellular medium into the cellular milieu indicated that the observed toxicity may be due in some cases to selective transport and further metabolism. This work contributes to understanding the neurotoxicity of LC-PCB hydroxylated and sulfated metabolites and the role that binding to serum proteins may play in it. Furthermore, it emphasizes the need for future studies on the effects that metabolism, particularly sulfation, may play in the disposition of LC-PCB congeners as it pertains to their metabolism, retention, and toxic effects.

Recently, persistent organic pollutants such as polychlorinated biphenyls (PCBs) were classified as “metabolic disruptors” for their suspected roles is altering metabolic and energy homeostasis through bioaccumulation in liver and adipose tissues. Among PCBs, a specific congener, 3,3',4,4',5-pentachlorobiphenyl (PCB126), is a potent arylhydrocarbon receptor (AhR) agonist and elicits toxicity similar to the classic dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). PCB126 levels found in human blood are particularly associated with diabetes and nonalcoholic fatty liver disease (NAFLD) in humans, however the mechanisms are unclear. We hypothesized that the accumulation of PCB126 disrupts carbohydrate and lipid metabolism by altering the functions of liver and adipose tissues. Hence, our objective was to characterize PCB126 induced-metabolic disruption and the underlying molecular mechanisms that cause toxicity. Separate animal studies were performed using a rat model to understand the time- and dose-dependent effects after PCB126 administration. The chronology of PCB126 toxicity showed early decreases in serum glucose level at 9 h, worsened in a time-dependent way until the end of the study at 12 d. Lipid accumulation and the liver pathology also worsened over time between 3 d and 12 d post administration. These observed effects in the liver were also found to be dose-dependent. The decrease in serum glucose was a result of a decrease in the transcript levels of gluconeogenic and glycogenolytic enzymes, necessary for hepatic glucose production and hence the maintenance of steady glucose levels in the blood. Phosphoenolpyruvate carboxykinase (PEPCK-C), the rate limiting enzyme of gluconeogenesis, was found to be significantly decreased upon exposure to PCB126. The expression levels of peroxisome proliferator-activated receptor alpha (Pparα) and some of its targets involved in fatty acid oxidation were also found to be time and dose-dependently decreased upon exposure to PCB126. In an attempt to understand the molecular targets that may cause these dual effects on both gluconeogenic and fatty acid oxidation, we found that PCB126 significantly decreases phosphorylation of the cAMP response element-binding protein (CREB). CREB is a nuclear transcription factor that is activated in the liver through phosphorylation; to switch-on the transcription of enzymes that catalyze gluconeogenesis and fatty acid oxidation, in order to meet energy demands, especially during fasting. Further, to understand the toxicity of PCB126 on adipose tissue, a human pre-adipocyte model that can be differentiated into mature adipocytes was used. In these studies, we found that exposure of preadipocytes to PCB126 resulted in a significant reduction in their ability to differentiate into adipocytes. This results in decreased lipid accumulation in the adipocyte. Reduction in the differentiation by PCB126 was associated with down regulation in transcript levels of a key adipocyte transcription factor, PPARγ and its transcriptional targets necessary for adipogenesis and adipocyte function. These inhibitory effects of PCB126 on the regulation of PPARγ and the initiation of adipogenesis were mediated through activation of AhR. Overall, this work shows that PCB126 disrupts nutrient homeostasis through its effects on the function of target tissues; liver and adipose. PCB126 significantly alters the nutrient homeostasis through its effects on gluconeogenesis and fatty-acid oxidation necessary for glucose and energy regulation during fasting. In addition, PCB126 interrupts the storage functions of adipose tissue by inhibiting adipogenesis and thus disrupts lipid storage and distribution

Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2008.

The objective of this thesis is to improve the understanding of what processes and mechanism affects the distribution of polychlorinated biphenyls (PCBs) and organic carbon in coastal sediments. Because of the strong association of hydrophobic organic contaminants (HOCs) such as PCBs with organic matter in the aquatic environment, these two entities are naturally linked. The coastal environment is the most complex and dynamic part of the ocean when it comes to both cycling of organic matter and HOCs. This environment is characterised by the largest fluxes and most diverse sources of both entities. A wide array of methods was used to study these processes throughout this thesis. In the field sites in the Stockholm archipelago of the Baltic proper, bottom sediments and settling particulate matter were retrieved using sediment coring devices and sediment traps from morphometrically and seismically well-characterized locations. In the laboratory, the samples have been analysed for PCBs, stable carbon isotope ratios, carbon-nitrogen atom ratios as well as standard sediment properties. From the fieldwork in the Stockholm Archipelago and the following laboratory work it was concluded that the inner Stockholm archipelago has a low (≈ 4%) trapping efficiency for freshwater-derived organic carbon. The corollary is a large potential for long-range waterborne transport of OC and OC-associated nutrients and hydrophobic organic pollutants from urban Stockholm to more pristine offshore Baltic Sea ecosystems. Theoretical work has been carried out using Geographical Information Systems (GIS) and statistical methods on a database of 4214 individual sediment samples, each with reported individual PCB congener concentrations. From this work it was concluded that the continental shelf sediments are key global inventories and ultimate sinks of PCBs. Depending on congener, 10-80% of the cumulative historical emissions to the environment are accounted for in continental shelf sediments. Further it was concluded that the many infamous and highly contaminated surface sediments of urban harbours and estuaries of contaminated rivers cannot be of importance as a secondary source to sustain the concentrations observed in remote sediments. Of the global shelf PCB inventory < 1% are in sediments near population centres while ≥ 90% is in remote areas (> 10 km from any dwellings). The remote sub-basin of the North Atlantic Ocean contains approximately half of the global shelf sediment inventory for most of the PCBs studied.

Background and objective: Major risk factors for congestive heart failure (CHF) are myocardial infarction, hypertension, diabetes, atrial fibrillation, smoking, left ventricular hypertrophy (LVH) and obesity. However, since these risk factors only explain part of the risk of CHF, we investigated whether persistent organic pollutants (POPs) might also play a role. Methods: In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, left ventricular ejection fraction, (EF), E/A-ratio and isovolumic relaxation time (IVRT), were determined by echocardiography and serum samples of 21 POPs were analyzed in serum measured by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) in 998 subjects all aged 70 years. Results: In this cross-sectional analysis, high levels of several of the polychlorinated biphenyls (PCB congeners 99, 118, 105, 138, 153, and 180) and octachlorodibenzo-p-dioxin (OCDD) were significantly related to a decreased EF. Some POPs were also related to a decreased E/A-ratio (PCBs 206 and 209). All the results were adjusted for gender, hypertension, diabetes, smoking, LVH and BMI, and subjects with myocardial infarction or atrial fibrillation were excluded from the analysis. Conclusions: Circulating levels of POPs were related to impairments in both left ventricular systolic and diastolic function independently of major congestive heart failure risk factors, suggesting a possible role of POPs in heart failure.

Ion mobility spectroscopy (IMS) has been showen to provide fast on-site analysis of coarse sandy soil for the determination of polychlorinated biphenyls (PCBs). However the presence of humus results in instrument foaling and extensive down time do to instrument clean-up. For this reason a method was investigated for the ultrasonic extraction of PCBs from humus-rich soil that could be used at remote locations. Analysis of the extracted PCBs was conducted using 1) IMS and 2) gas chromatogram equipped with a dry electolytic conductiviy detector (GC/DELCD). The research conducted for this thesis outlines the method development and analysis of PCBS using these two instruments. The IMS analyiss was found to be complicated by co-extracted matrix compounds. Results and limitations of IMS analysisare present here. The method development and validation of a method for the ultrasonic extraction and analysis of PCBs using the GC/DELCD is provided.

Ion mobility spectroscopy (IMS) has been showen to provide fast on-site analysis of coarse sandy soil for the determination of polychlorinated biphenyls (PCBs). However the presence of humus results in instrument foaling and extensive down time do to instrument clean-up. For this reason a method was investigated for the ultrasonic extraction of PCBs from humus-rich soil that could be used at remote locations. Analysis of the extracted PCBs was conducted using 1) IMS and 2) gas chromatogram equipped with a dry electolytic conductiviy detector (GC/DELCD). The research conducted for this thesis outlines the method development and analysis of PCBS using these two instruments. The IMS analyiss was found to be complicated by co-extracted matrix compounds. Results and limitations of IMS analysisare present here. The method development and validation of a method for the ultrasonic extraction and analysis of PCBs using the GC/DELCD is provided.