Serum concentrations of phthalate metabolites are related to abdominal fat distribution two years later in elderly women

BACKGROUND: Phthalates, commonly used to soften plastic goods, are known PPAR-agonists affecting lipid metabolism and adipocytes in the experimental setting. We evaluated if circulating concentrations of phthalates were related to different indices of obesity using data from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Data from both dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) were used. METHODS: 1,016 subjects aged 70 years were investigated in the PIVUS study. Four phthalate metabolites were detected in the serum of almost all subjects (> 96%) by an API 4000 liquid chromatograph/tandem mass spectrometer. Abdominal MRI was performed in a representative subsample of 287 subjects (28%), and a dual-energy X-ray absorptiometry (DXA)-scan was obtained in 890 (88%) of the subjects two year following the phthalate measurements. RESULTS: In women, circulating concentrations of mono-isobutyl phthalate (MiBP) were positively related to waist circumference, total fat mass and trunk fat mass by DXA, as well as to subcutaneous adipose tissue by MRI following adjustment for serum cholesterol and triglycerides, education, smoking and exercise habits (all p < 0.008). Mono-methyl phthalate (MMP) concentrations were related to trunk fat mass and the trunk/leg-ratio by DXA, but less powerful than MiBP. However, no such statistically significant relationships were seen in men. CONCLUSIONS: The present evaluation shows that especially the phthalate metabolite MiBP was related to increased fat amount in the subcutaneous abdominal region in women measured by DXA and MRI two years later

Environmental Contaminants and Obesity

Obesity is a worldwide problem affecting both children and adults. Genetic, physiological, environmental, psychological, social and economic factors interact in varying degrees, influencing body weight and fat distribution and the progress of obesity. Moreover, some anthropogenic chemicals have proven to be endocrine disrupting chemicals (EDCs) with the potential to interfere with different actions of hormones in the body. EDCs may thereby disrupt homeostasis, modifying developmental, behavioral and immune functions in humans and animals, and also promoting adiposity. Because hormones generally act at low concentrations, small changes in the endocrine system may lead to extensive effects. Based on data from experimental and epidemiological studies this thesis elucidates the relationship between a large number of environmental contaminants and obesity. The experimental studies demonstrated that fructose supplementation in the drinking water resulted in unfavorable metabolic alterations such as a higher liver somatic index (LSI), an increase in plasma triglycerides and increased plasma levels of apo A-I. Fructose in combination with exposure to bisphenol A (BPA) increased liver fat content and plasma levels of apo A-I in juvenile female Fischer 344 rats. The experimental studies also showed that the retro-peritoneal fat, which in rats is a distinct fat depot easy to distinguish and dissect, correlated well with the measurements of total fat mass analyzed with MRI, and could therefore be used as a substitute for total fat mass in rats. The epidemiological studies showed that circulating levels of persistent organic pollutants (POPs) were related to fat mass measured by DXA. OCDD, HCB, TNC, DDE and the less chlorinated PCBs were positively related to fat mass, while the more highly chlorinated PCBs showed a negative association. Further, circulating levels of BPA were positively associated with levels of the hormones adiponectin and leptin, but negatively related with ghrelin, hormones which are involved in the regulation of hunger and satiety. However, serum BPA levels were not related to measures of fat mass in the elderly individuals in the PIVUS cohort. This thesis concludes that environmental contaminants such as BPA and POPs most likely are contributors, along with genetic, social and behavioral factors, to the development of obesity

Environmental Contaminants and Obesity

Obesity is a worldwide problem affecting both children and adults. Genetic, physiological, environmental, psychological, social and economic factors interact in varying degrees, influencing body weight and fat distribution and the progress of obesity. Moreover, some anthropogenic chemicals have proven to be endocrine disrupting chemicals (EDCs) with the potential to interfere with different actions of hormones in the body. EDCs may thereby disrupt homeostasis, modifying developmental, behavioral and immune functions in humans and animals, and also promoting adiposity. Because hormones generally act at low concentrations, small changes in the endocrine system may lead to extensive effects. Based on data from experimental and epidemiological studies this thesis elucidates the relationship between a large number of environmental contaminants and obesity. The experimental studies demonstrated that fructose supplementation in the drinking water resulted in unfavorable metabolic alterations such as a higher liver somatic index (LSI), an increase in plasma triglycerides and increased plasma levels of apo A-I. Fructose in combination with exposure to bisphenol A (BPA) increased liver fat content and plasma levels of apo A-I in juvenile female Fischer 344 rats. The experimental studies also showed that the retro-peritoneal fat, which in rats is a distinct fat depot easy to distinguish and dissect, correlated well with the measurements of total fat mass analyzed with MRI, and could therefore be used as a substitute for total fat mass in rats. The epidemiological studies showed that circulating levels of persistent organic pollutants (POPs) were related to fat mass measured by DXA. OCDD, HCB, TNC, DDE and the less chlorinated PCBs were positively related to fat mass, while the more highly chlorinated PCBs showed a negative association. Further, circulating levels of BPA were positively associated with levels of the hormones adiponectin and leptin, but negatively related with ghrelin, hormones which are involved in the regulation of hunger and satiety. However, serum BPA levels were not related to measures of fat mass in the elderly individuals in the PIVUS cohort. This thesis concludes that environmental contaminants such as BPA and POPs most likely are contributors, along with genetic, social and behavioral factors, to the development of obesity

Environmental Contaminants and Obesity

Obesity is a worldwide problem affecting both children and adults. Genetic, physiological, environmental, psychological, social and economic factors interact in varying degrees, influencing body weight and fat distribution and the progress of obesity. Moreover, some anthropogenic chemicals have proven to be endocrine disrupting chemicals (EDCs) with the potential to interfere with different actions of hormones in the body. EDCs may thereby disrupt homeostasis, modifying developmental, behavioral and immune functions in humans and animals, and also promoting adiposity. Because hormones generally act at low concentrations, small changes in the endocrine system may lead to extensive effects. Based on data from experimental and epidemiological studies this thesis elucidates the relationship between a large number of environmental contaminants and obesity. The experimental studies demonstrated that fructose supplementation in the drinking water resulted in unfavorable metabolic alterations such as a higher liver somatic index (LSI), an increase in plasma triglycerides and increased plasma levels of apo A-I. Fructose in combination with exposure to bisphenol A (BPA) increased liver fat content and plasma levels of apo A-I in juvenile female Fischer 344 rats. The experimental studies also showed that the retro-peritoneal fat, which in rats is a distinct fat depot easy to distinguish and dissect, correlated well with the measurements of total fat mass analyzed with MRI, and could therefore be used as a substitute for total fat mass in rats. The epidemiological studies showed that circulating levels of persistent organic pollutants (POPs) were related to fat mass measured by DXA. OCDD, HCB, TNC, DDE and the less chlorinated PCBs were positively related to fat mass, while the more highly chlorinated PCBs showed a negative association. Further, circulating levels of BPA were positively associated with levels of the hormones adiponectin and leptin, but negatively related with ghrelin, hormones which are involved in the regulation of hunger and satiety. However, serum BPA levels were not related to measures of fat mass in the elderly individuals in the PIVUS cohort. This thesis concludes that environmental contaminants such as BPA and POPs most likely are contributors, along with genetic, social and behavioral factors, to the development of obesity

Nachhaltigkeitsbewertung partizipativer Produktionskonzepte und Entwicklung eines qualitativen Bewertungs-Tools auf der Basis von Zufriedenheit

Im Projekt wurden die Nachhaltigkeitspotentiale partizipativer landwirtschaftlicher Produktionskonzepte exemplarisch untersucht und der Versuch gemacht, deren Zufriedenheitspotential für Erzeuger und Bürger zu erfassen. Die landwirtschaftlichen Betriebe konnten dabei auf der Grundlage der Leitlinien der Sustainability Assessment of Food and Agriculture (SAFA) in den Dimensionen gute Unternehmensführung, ökologische Integrität, ökonomische Resilienz und soziales Wohlergehen bewertet werden. Die einzelnen Ergebnisse sind nach Dimensionen und korrespondierenden Indikatoren in diesem Working Paper beschrieben. Zudem konnten Handlungsempfehlungen auch dazu erarbeitet werden, wie Untersuchungen anhand der SAFA-Leitlinien erfolgreich durchgeführt werden können

Bioactivation and effects of environmental pollutants in human and rodent blood vessel endothelial cells

Introduction Recent epidemiological studies reveal associations between exposure to environmental pollutants and cardiovascular disorders in humans. Elevated serum concentrations of polychlorinated biphenyls (PCBs) have for instance been associated with cardiovascular risk factors such as hypertension (1-3). Exposure to the carbonate plastic monomer bisphenol A (BPA) has been associated with an increased incidence of cardiovascular disease and atherogenic changes in the vascular wall (4-6). The contention that the human cardiovascular system is a sensitive target for toxic chemicals gain support from our earlier and recent experimental studies in rodents, birds and fish, as well as in cultured human primary endothelial cells. It is also compatible with earlier observations that certain polycyclic aromatic hydrocarbons (PAHs) are environmental carcinogens that may also contribute to atherosclerosis in mice and birds (7,8). In this presentation we will briefly discuss effects of Ah receptor (AhR) agonists (e.g. the coplanar PCB126 or BNF, ß-naphthoflavone) on the expression of cytochrome P450 (CYP)1 enzymes in various endothelia in rodents in vivo or ex vivo, as well as in cultured human umbilical vein endothelial cells (HUVEC). The CYP1-dependent bioactivation and irreversible binding of prototype polyaromatic hydrocarbons (PAH) and heterocyclic amines such as benzo(a)pyrene (BaP), 7,12-dimethyl- benz(a)anthracene (DMBA) and 3-amino-1,4-dimethyl-5H-pyrido- [4,3-b]indole (Trp-P1) in these endothelia will be reviewed. We will also report how PCB126 affects vasoactive factors in HUVEC, and how these effects are modulated by physiological 17ß-oestradiol concentrations. Some effects of PCB126, 1-nitropyrene (1-NP) and bisphenol A (BPA) on biomarkers for endothelial dysfunction, cell stress and DNA damage in HUVEC will finally be presented. Material and methods Human umbilical vein endothelial cells (HUVEC) were purchased from Science Cell Research laboratories, Carlsbad, CA. C57Bl mice and Wistar or Sprague Dawley rats were purchased from various suppliers. All animal experiments were approved by the Local Ethical Committee for Research on Animals in Uppsala and the studies followed the guidelines laid down by the Swedish and European Union legislation on animal experimentation. Rodents, tissue-slices and cultured cells were treated with model chemicals as previously described. Tape section and light microscopy autoradiographic imaging using 3H-labelled BaP, DMBA and Trp-P-1 and immunohistochemistry was performed as previously described (9-19). Precision-cut tissue slices for in vitro autoradiography were prepared as described in (14) and the slices were incubated with various 3H-labelled chemicals. HUVEC were exposed to various compounds and the detection of biomarkers of endothelial dysfunction, DNA damage were performed as described (20-22). Finally, female Fischer rats were exposed to BPA (0.025, 0.25 and 2.5 mg/l) and fructose (50 g/l) in the drinking water from 5 to 15 weeks of age to mimic human exposure (unpublished data). Results and discussion Co-localization of CYP1A1 expression and BaP, DMBA and Trp-P-1 adduct formation in endothelial linings As demonstrated by immunohistochemistry, a high CYP1A immunoreactivity occurred in capillaries of the heart, skeletal muscle, uterus and in blood-brain interfaces such as the leptomeninges and plexus choroideus, whereas no expression was observed for instance in cerebral capillary endothelial cells of mice treated with AhR agonists (9-11). No, or very low constitutive immunoreactivities were observed in these endothelia in vehicle-treated animals. No basal or induced CYP1B1 expression was observed in endothelial cells, while a weak CYP1B1 immunostaining was detected in the muscle layer of small arteries. It should be noted that in subcellular preparations of whole organs, e.g. heart and brain, the CYP1A1 in endothelial cells is diluted due to cells that do not express high levels of CYP1A1, for examples myocytes or neurons, in excess. A cell-specific metabolism in endothelial cells may therefore remain undetected due to the presence of metabolically inactive cells. In order to detect minor sites of bioactivation such as endothelial linings we employed light microscopic autoradiographic imaging to examine the bioactivation and subsequent irreversible binding of the radiolabelled prototype toxicants in tissues of animals pretreated with AhR-agonists. As determined by light microscopic autoradiography of AhR-agonist-treated mice exposed to 3H-labelled BaP, DMBA or Trp-P-1 and birds exposed to 3H-Trp-P-1 a significant accumulation of non-extractable radioactivity occurred in endothelial linings (9-18). The bound radioactivity occurred in the nuclei and the perinuclear cytoplasm, suggesting that the autoradiograms depict both DNA- and protein-bound adducts. Since the binding sites of 3H-labelled BaP, DMBA or Trp-P-1 corresponded with the sites of CYP1A1 induction, we concluded that rodents express a constitutively low but highly inducible and functional CYP1A1 in endothelial cells. The binding of reactive metabolites in endothelial cells exceeded the binding in all other cell types in AhR-agonist treated mice and was abolished by pretreatment with the CYP1A1 inhibitor ellipticine, supporting a CYP1A1-catalysed metabolic activation in situ to a reactive species (9, 10,12). These findings imply that there is a preferential CYP1A1-catalysed formation of reactive metabolites from all three carcinogens in endothelial cells expressing high CYP1A1 levels. Interestingly, however, carcinogenesis in endothelial cells is a relative rare finding, suggesting that degenerative lesions and cell death may be more prevalent responses to metabolism-activated carcinogens/mutagens in these cells. Experiments with 3H-DMBA and 3H-Trp-P-1 in HUVEC confirmed that AhR-agonists induced an increased bioactivation, suggesting that also human endothelial cells should be targets for toxicity of reactive intermediates formed from CYP1A1- activated carcinogens/mutagens (17-18). This conclusion is supported by immunohistochemical studies on the heavily vascularized human endometrium demonstrating an expression of CYP1A1 and CYP1B1 protein in and around human endometrial blood vessels, although a large interindividual variation was observed (19). None of the endometrial biopsy samples displayed vascular expression of CYP2A6, CYP2B6, CYP2C8/2C9/2C19, CYP2D6, or CYP3A4/5 protein. Effects of PCB 126, 1-NP, and BPA on biomarkers of endothelial dysfunction and cell stress in endothelial cells In vitro studies demonstrated that PCB126 increased the levels of vasoconstriction factors and decreased the levels of vasodilating factors in cultured HUVEC in a fashion that is characteristic for endothelial dysfunction related to human hypertension. The study showed that the co-planar PCB126 induced expression of the endothelium-derived vasoconstriction factor COX-2 and stimulated formation of the vasoconstrictor prostaglandin PGF2 via the AhR in HUVEC (20). COX-2 is known to play a role in hypertension by catalysing the formation of vasoconstriction prostaglandins and by stimulating reactive oxygen species (ROS) production. Further studies demonstrated that PCB126 increased the production of the vasoconstriction prostaglandin PGF2 and ROS in HUVEC. The relationship between increased ROS production and human hypertension is well established, ROS promotes vasoconstriction by stimulating the production of vasoconstriction prostaglandins and by reducing bioavailability of the vasorelaxing factor NO. Indeed, exposure to PCB126 slightly reduced the production of NO in HUVEC. Furthermore, the PCB126-induced mRNA expressions of CYP1A1, CYP1B1 and COX-2 in HUVEC were enhanced in the presence of physiological levels of 17- estradiol. This suggests that increased levels of oestrogen stimulate AhR-dependent transcription of genes previously associated with endothelial dysfunction and hypertension. In another study we have examined the effects of a nitrated PAH, 1-nitropyrene, that is abundant in diesel exhausts (21). The results revealed that 1-NP induced DNA damage, increased levels of ROS and increased protein expression of the endoplasmic reticulum stress chaperone GRP78 in cultured HUVEC. Induction of CYP1A1 by PCB126 as well as inhibition of nitroreductive metabolism by dicoumarol attenuated the induction of DNA damage, intracellular ROS levels and GRP78 expression. This suggests that the effects of 1-NP on HUVEC were mediated by metabolites mainly formed at nitroreduction and not by CYP1-dependent bioactivation to reactive intermediates. Recent in vitro studies demonstrated that bisphenol A increased the mRNA expression of genes that regulate vasoconstriction and angiogenesis in HUVEC (eNOS, VEGF, VEGFR2, connexin 43 and ACE1) and in human cardiomyocytes (eNOS and ACE1) (22). The results also showed that BPA increased the expression of P-eNOS(ser1177) and the production of NO in HUVEC. NO is the main effector molecule in angiogenesis downstream of VEGF. Based on the findings that BPA increase the expression of proangiogenic factors we investigated whether BPA could stimulate in vitro angiogenesis in HUVEC using the endothelial tube formation assay. The results demonstrated that BPA increased HUVEC tube formation suggesting that BPA can act directly on the endothelium and stimulate angiogenesis. Long-term exposure in rats revealed that environmentally relevant levels of BPA, increased the cardiac mRNA expression of genes that regulate vasoconstriction and angiogenesis. Ten weeks exposure of rats from preadolescence to adulthood to BPA in the drinking water increased the expression of eNOS, VEGF, VEGFR2 and ACE1 in the heart. Taken together, the genes that were upregulated in rat cardiac tissues in vivo were also upregulated in human endothelial cells and cardiomyocytes in vitro. The heart is a heavily vascularized tissue that consists mainly of cardiac endothelial cells and cardiomyocytes and although cardiomyocytes dominate the volume of the myocardium the number of endothelial cells exceeds the number of cardiomyocytes by approximately three to one. Thus, the effects of BPA on eNOS VEGF, VEGFR2 and ACE1 mRNA expression in rat cardiac tissues are most likely to be related to an effect of BPA on endothelial cells but may also involve cardiomyocytes. We conclude that endothelial cells may be targets for bioactivation and toxicity of environmental pollutants. The immunohistochemical and autoradiographic data demonstrated a differential expression of CYP1 enzymes and metabolic activation of pollutants in various endothelial linings suggesting that some but not all endothelial linings may be targets for xenobiotics metabolised by AhR-regulated enzymes. Studies on the effects of PCB126, 1-nitropyrene and BPA in cultured human primary endothelial cells demonstrated up-regulation of various biomarkers for endothelial dysfunction and cell stress suggesting that the human endothelium may be a sensitive target for these pollutants. The bioactivation and effects of environmental pollutants in endothelial cells should be further studied in order to unravel the role of these chemicals in human cardiovascular disease

Serum concentrations of phthalate metabolites are related to abdominal fat distribution two years later in elderly women

Abstract Background Phthalates, commonly used to soften plastic goods, are known PPAR-agonists affecting lipid metabolism and adipocytes in the experimental setting. We evaluated if circulating concentrations of phthalates were related to different indices of obesity using data from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Data from both dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) were used. Methods 1,016 subjects aged 70 years were investigated in the PIVUS study. Four phthalate metabolites were detected in the serum of almost all subjects (> 96%) by an API 4000 liquid chromatograph/tandem mass spectrometer. Abdominal MRI was performed in a representative subsample of 287 subjects (28%), and a dual-energy X-ray absorptiometry (DXA)-scan was obtained in 890 (88%) of the subjects two year following the phthalate measurements. Results In women, circulating concentrations of mono-isobutyl phthalate (MiBP) were positively related to waist circumference, total fat mass and trunk fat mass by DXA, as well as to subcutaneous adipose tissue by MRI following adjustment for serum cholesterol and triglycerides, education, smoking and exercise habits (all p Conclusions The present evaluation shows that especially the phthalate metabolite MiBP was related to increased fat amount in the subcutaneous abdominal region in women measured by DXA and MRI two years later.</p

Low-dose exposure to bisphenol A in combination with fructose increases expression of genes regulating angiogenesis and vascular tone in juvenile Fischer 344 rat cardiac tissue

Objectives: Epidemiological studies report associations between exposure to the high-volume chemical and endocrine disruptor bisphenol A (BPA) and cardiovascular disorders, but there is a lack of experimental studies addressing the mechanisms of action of BPA on the cardiovascular system. In the present study, effects on markers for cardiovascular function of exposure to BPA and fructose in vivo in rat cardiac tissues, and of BPA exposure in human cardiomyocytes in vitro, were investigated. Materials: Juvenile female Fischer 344 rats were exposed to 5, 50, and 500 μg BPA/kg bodyweight/day in their drinking water from 5 to 15 weeks of age, in combination with 5% fructose. Further, cultured human cardiomyocytes were exposed to 10 nM BPA to 1 × 104 nM BPA for six hours. Expression of markers for cardiovascular function and BPA target receptors was investigated using qRT-PCR. Results: Exposure to 5 μg BPA/kg bodyweight/day plus fructose increased mRNA expression of Vegf, Vegfr2, eNos, and Ace1 in rat heart. Exposure of human cardiomyocytes to 1 × 104 nM BPA increased mRNA expression of eNOS and ACE1, as well as IL-8 and NFκβ known to regulate inflammatory response. Conclusions:. Low-dose exposure of juvenile rats to BPA and fructose induced up-regulation of expression of genes controlling angiogenesis and vascular tone in cardiac tissues. The observed effects of BPA in rat heart were in line with our present and previous studies of BPA in human endothelial cells and cardiomyocytes. These findings may aid in understanding the mechanisms of the association between BPA exposure and cardiovascular disorders reported in epidemiological studies

Bisphenol A exposure increases liver fat in juvenile fructose-fed Fischer 344 rats

Background Prenatal exposure to bisphenol A (BPA) has been shown to induce obesity in rodents. To evaluate if exposure also later in life could induce obesity or liver damage we investigated these hypothesises in an experimental rat model. Methods From five to fifteen weeks of age, female Fischer 344 rats were exposed to BPA via drinking water (0.025, 0.25 or 2.5 mg BPA/L) containing 5% fructose. Two control groups were given either water or 5% fructose solution. Individual weight of the rats was determined once a week. At termination magnetic resonance imaging was used to assess adipose tissue amount and distribution, and liver fat content. After sacrifice the left perirenal fat pad and the liver were dissected and weighed. Apolipoprotein A-I in plasma was analyzed by western blot. Results No significant effects on body weight or the weight of the dissected fad pad were seen in rats exposed to BPA, and MRI showed no differences in total or visceral adipose tissue volumes between the groups. However, MRI showed that liver fat content was significantly higher in BPA-exposed rats than in fructose controls (p = 0.04). BPA exposure also increased the apolipoprotein A-I levels in plasma (p &lt; 0.0001). Conclusion We found no evidence that BPA exposure affects fat mass in juvenile fructose-fed rats. However, the finding that BPA in combination with fructose induced fat infiltration in the liver at dosages close to the current tolerable daily intake (TDI) might be of concern given the widespread use of this compound in our environment