Cocktails of endocrine disruptors in the different diets of French consumers.

With a view to identifying main endocrine disruptors (ED) mixtures to which French consumers are exposed through food, their main diets were modelled using an adapted dimension reduction method. Seven specific diets could be modelled for adults while only one overall diet was considered for children aged 3-17 years. The knowledge of the contamination levels of 78 known or suspected endocrine disrupting compounds in the foods constituting these diets, collected in the frame of the second French Total Diet Study, made it possible to explore the mixtures of EDs to which consumers are exposed. We have thus shown that the ED substances most present in mass concentration are comparable for the whole population, whatever the diet considered. However, a second approach made it possible to highlight, for a given diet, the substances whose exposure is statistically higher than in the diet of the general population. Thus, significantly different ED mixtures could be established for each diet. For example, diets with a high proportion of animal-based foods induce significantly higher exposures to some persistent organic pollutants (e.g., PCDD/F, brominated flame retardants), whereas these exposures are lower for Mediterranean-type diet. On the other hand, the latter, richer in fruits and vegetables, is the one for which pesticides represent a specific signature.These results now pave the way for studying the specific effects of these cocktails of endocrine disruptors, each of which is representative of a type of chronic exposure linked to specific diets.

Obesogen effects after perinatal exposure of 4,4'-sulfonyldiphenol (Bisphenol S) in C57BL/6 mice.

Bisphenol A were removed from consumer products and replaced by chemical substitutes such as Bisphenol S (BPS). Based on their structural similarity, BPS may be obesogen like Bisphenol A in mice. Our objective was to determine the impact of BPS on lipid homeostasis in C57Bl/6 mice after perinatal and chronic exposure. Pregnant mice were exposed to BPS via the drinking water (0.2; 1.5; 50µg/kg bw/d). Treatment began at gestational day 0 and continued in offspring up to 23-weeks old. Then, offspring mice were fed with a standard or high fat diet. The body weight, food consumption, fat mass and energy expenditure were measured. A lipid load test was performed to check the postprandial triglyceridemia. Plasma parameters and mRNA gene expression in adipose tissues were also analysed. BPS induced overweight in male mice offspring fed with a HFD at the two highest doses. There was no change in food intake and energy expenditure. The overweight was correlated to the fat mass, hyperinsulinemia and hyperleptinemia. The plasma triglyceride clearance was significantly increased with BPS and tyloxapol(®) (triglyceride clearance inhibitor) reversed this phenomenon. BPS induced alteration in mRNA expression of marker genes involved in adipose tissue homeostasis: hormone sensitive lipase, PPARγ, insulin receptor, SOCS3 and adiponectin. This is the first time that BPS is described as obesogenic at low doses and after perinatal and chronic exposure in male mice. BPS potentiated the obesity induced by a HFD by inducing the lipid storage linked to faster lipid plasma clearance.

The consequences of physical post-treatments (microwave and electron-beam) on food/packaging interactions: A physicochemical and toxicological approach.

The safety of microwave and electron-beam treatments has been demonstrated, in regards to the formation of reaction products that could endanger human health. An integrated approach was used combining the potential toxicity of all the substances likely to migrate to their chemical characterizations. This approach was applied to polypropylene (PP) films prepared with a selection of additives. Components were identified by liquid and gas chromatography using a mass selective detector system. Their potential toxicity was assessed using three in vitro short-term bioassays and their migrations were carried out using a standards-based approach. After the electron-beam treatment some additives decomposed and there was a significant increase in the polyolefin oligomeric saturated hydrocarbons concentration. PP prepared with Irgafos 168 led to a significantly strong cytotoxic effect and PP prepared with Irganox 1076 induced a dose-dependant estrogenic effect in vitro. Migration values were low and below the detection limit of the analytical method applied.

BPA, an energy balance disruptor.

Bisphenol A (BPA) is used extensively in the world and is present in a diverse range of manufactured articles including dental resins, polycarbonate plastics, and the inner coating of food cans. It is a high volume chemical, with global production at 3.6 × 10(9) kg per year. BPA was identified as a high priority for assessment of human health risk because it was considered to present greatest potential for human exposure. Most studies of the health effects of BPA have focused on endocrine disruption leading to reproductive toxicity, but it displays additional side effects, including liver damage, disrupted pancreatic ß-cell function, thyroid hormone disruption, and obesity-promoting effects. In this article, we reviewed specifically on the effects of BPA in energy balance.

Post-initiation modulating effects of allyl sulfides in rat hepatocarcinogenesis.

Effects of administration of diallyl sulfide (DAS) and diallyl disulfide (DADS) on the promotion stage of hepatocarcinogenesis were investigated in rats using the Ito model. They were compared with those of phenobarbital (PB), a well-known liver promoter in rats. Initiation was induced by a single dose of N-nitrosodiethylamine (NDEA) and 3 weeks later, a partial hepatectomy was conducted. Two weeks after the NDEA injection, rats received either 0.05% allyl sulfides, PB or both in their diet for 8 weeks. Feeding with DAS increased the number of liver preneoplastic foci by 63% with respect to the untreated group. However, rats fed DAS showed a lower foci development than rats fed PB. The DADS group did not differ from control group for any of the measured morphometric parameters. Simultaneous administration of DADS with PB partially reduced the promotional activity of PB whereas DAS co-treatment did not modify PB properties. These findings confirm that DAS can act as a promoter in rat liver but exerts no co-promoting effect. Conversely, DADS was found to have promotion-inhibiting ability, suggesting that DADS has greater value than DAS as a chemopreventive agent.

Steroid activities comparison of natural and food wrap compounds in human breast cancer cell lines.

In this study, we tested and compared the endocrine disruption activities of compounds in materials used to package foods (bisphenol A, bisphenol F, and bisphenol A diglycidylether BADGE) with natural molecules (genistein, apigenin, kaempferol, and tangeretin) in the human breast cancer cell lines MCF-7 (ER(+)) and MDA-MB453 (AR(+); GR(+)). Octylphenol was also chosen as a xenoestrogen reference. Two compounds had no estrogenic activity: BADGE and tangeretin. Genistein was the most active compound in the E-Screen assay with MCF-7, followed by octylphenol, bisphenol F, bisphenol A and apigenin, with kaempferol the least potent. All estrogenic compounds competed with 17beta-estradiol for binding to the MCF-7 ER and their estrogenic effects were abolished in the presence of tamoxifen, an ER antagonist. In MDA-MB453 cells transfected with pMMTVneo-Luc, all compounds had anti-androgenic activities, with octylphenol the most potent. Kaempferol, genistein, and apigenin were more potent anti-androgens than bisphenols A or F. The natural compounds had a biphasic effect on luciferase activity. At high concentrations, genistein (10(-5)M) and apigenin (10(-6)M) acted as GR agonists in transfected MDA-MB453 cells. Furthermore, apigenin, at a concentration of 10(-5)M, may act as a partial androgen receptor (AR) agonist, as nilutamide, an AR antagonist, inhibited its activity by 26%.

Estrogenic activity and metabolism of n-butyl benzyl phthalate in vitro: identification of the active molecule(s).

Some phthalates are suspected to disrupt the endocrine system, especially by mimicking estrogens. N-butyl benzyl phthalate (BBP) has estrogenic effects in vitro but not in vivo. The aim of this study was to identify the active molecule(s) (parent compound and/or metabolite(s)) involved in the estrogenic activities of BBP. The estrogenic effects of BBP and its in vivo metabolites were assessed using the following tests: E-Screen, ER binding, and PR induction tests on the human breast cancer cell line MCF-7 (ER(+)). BBP, the parent compound, was a partial agonist. It stimulated MCF-7 proliferation in the E-Screen assay and increased cytosolic progesterone receptors (PR) levels in a concentration-dependent manner. No BBP metabolites were active except hippuric acid (HA), which had a weak effect at very high concentrations. BBP and HA stimulatory effects on MCF-7 proliferation were antagonized by tamoxifen. However, no competition was observed between BBP or HA and 17beta-estradiol for binding to the estrogen receptor (ER). BBP metabolism by MCF-7 cells was also investigated. After a 48-h incubation, only 10% of the initial BBP remained in the culture medium, demonstrating that BBP was extensively metabolized by the MCF-7 cells. The radioactivity recovered in the medium was represented by: mono-n-butyl phthalate (MBuP, 25%) and mono-n-benzyl phthalate (MBeP, 48%), phthalic acid (6%), and benzoic acid (3%). Since none of these metabolites had estrogenic activities, this study demonstrates that the parent compound was the active molecule involved in the in vitro estrogenic effects of BBP.

Metabolism of n-butyl benzyl phthalate in the female Wistar rat. Identification of new metabolites.

n-Butyl benzyl phthalate (BBP), a plasticizer used in polyvinylchloride (PVC) and other polymers, has been orally administered to female Wistar rats with four doses (150, 475, 780 and 1500 mg/kg body weight/day) for 3 consecutive days. Metabolites recovered in urines were analysed by gas chromatography-mass spectrometry (GC-MS) after 24, 48 and 72 hours. Six metabolites were identified. Mono-n-butyl phthalate (MBuP) and mono-n-benzyl phthalate (MBeP) represented respectively 29-34% and 7-12% of the total recovered metabolites. Hippuric acid, the main metabolite of benzoic acid, represented the second major metabolite (51-56%). Phthalic acid, benzoic acid and an omega-oxidized metabolite of MBuP were also recovered in urine but in small quantities. BBP was never identified in urines. Total urinary metabolites recovery represented 56% of the dose administered in the first 24 hours. However, total recovery decreased when the dose increases (43% at 780 mg/kg body weight/day, only 30% at 1500 mg/kg body weight/day). Whatever the time was, BBP metabolites recovered in urines were all present and in the same proportions for the two lowest doses. Discrepancy in metabolites quantities expressed as percentages of the dose observed in urine of rat treated with the highest BBP dose disappeared with time as MBuP, MBeP and hippuric acid recovery has significantly increased at day 3. Metabolic profile of BBP in female rats has been established. The aim of the present study is to identify further the active(s) agent(s) involved in the BBP malformations and teratogenic effects.

Fenofibrate: metabolism and species differences for peroxisome proliferation in cultured hepatocytes.

The hypolipidemic agent fenofibrate, which is a peroxisome proliferator in some rodents in vivo, was studied in cultured hepatocytes for its metabolism and effects on enzymatic induction related to peroxisome proliferation so as to lead to a better understanding of the mechanisms involved in peroxisome proliferation. [14C]-Fenofibrate was completely metabolized within 24 hr by primary cultures of rat hepatocytes and the metabolic pattern corresponded to that found in vivo. The main products were fenofibric acid and its glucuronidated form. Carbonyl reduction of fenofibric acid also occurred. The metabolic pattern of [14C]fenofibric acid was nearly the same as that of fenofibrate. Fenofibrate, fenofibric acid, and its reduced metabolite all induced peroxisomal (cyanide-insensitive) palmitoyl-CoA oxidation activity (PCOA) in rat hepatocytes, whereas derivatives lacking the carboxyl group were nearly inactive. The known species differences with respect to sensitivity to peroxisome proliferators in vivo was mirrored in cultured cells because fenofibric acid did not induce peroxisomal PCOA in primary culture of guinea pig hepatocytes nor in the human hepatoma cell line HepG2. The mechanistic association between the induction of CYP4A1-catalyzed lauric acid omega-hydroxylase (LAH) activity and peroxisomal PCOA induction was investigated. Fenofibric acid concomitantly induced LAH activity and peroxisomal PCOA in rat hepatocytes. Specific inhibition of LAH activity (-52%) by 10-undecynoic acid partially prevented induction of peroxisomal PCOA (-32%). The putative role of dicarboxylic acids, the oxidation product of omega-hydroxymonocarboxylic acids, in PCOA induction was further substantiated by the observed induction of peroxisomal PCOA by 1-12-dodecanedioic acid. We conclude that (1) fenofibric acid is the possible proximate peroxisome proliferator of fenofibrate in rat hepatocytes, (2) cultured hepatocytes reflect in vivo sensitivity to fenofibrate with respect to peroxisome proliferation, and (3) there is some evidence that the catalytic activity of the CYP4A1 enzyme mediates, at least in part, peroxisomal PCOA induction.