Effects of environmental Bisphenol A exposures on germ cell development and Leydig cell function in the human fetal testis

<div><p>Background</p><p>Using an organotypic culture system termed human Fetal Testis Assay (hFeTA) we previously showed that 0.01 μM BPA decreases basal, but not LH-stimulated, testosterone secreted by the first trimester human fetal testis. The present study was conducted to determine the potential for a long-term antiandrogenic effect of BPA using a xenograft model, and also to study the effect of BPA on germ cell development using both the hFETA and xenograft models.</p><p>Methods</p><p>Using the hFeTA system, first trimester testes were cultured for 3 days with 0.01 to 10 μM BPA. For xenografts, adult castrate male nude mice were injected with hCG and grafted with first trimester testes. Host mice received 10 μM BPA (~ 500 μg/kg/day) in their drinking water for 5 weeks. Plasma levels of total and unconjugated BPA were 0.10 μM and 0.038 μM respectively. Mice grafted with second trimester testes received 0.5 and 50 μg/kg/day BPA by oral gavage for 5 weeks.</p><p>Results</p><p>With first trimester human testes, using the hFeTA model, 10 μM BPA increased germ cell apoptosis. In xenografts, germ cell density was also reduced by BPA exposure. Importantly, BPA exposure significantly decreased the percentage of germ cells expressing the pluripotency marker AP-2γ, whilst the percentage of those expressing the pre-spermatogonial marker MAGE-A4 significantly increased. BPA exposure did not affect hCG-stimulated androgen production in first and second trimester xenografts as evaluated by both plasma testosterone level and seminal vesicle weight in host mice.</p><p>Conclusions</p><p>Exposure to BPA at environmentally relevant concentrations impairs germ cell development in first trimester human fetal testis, whilst gonadotrophin-stimulated testosterone production was unaffected in both first and second trimester testis. Studies using first trimester human fetal testis demonstrate the complementarity of the FeTA and xenograft models for determining the respective short-term and long term effects of environmental exposures.</p></div

Urinary signature of pig carcasses with boar taint by liquid chromatography-high resolution mass spectrometry

Boar taint is an offensive odor that can occur while cooking pork or pork products and is identified in some uncastrated male pigs that have reached puberty. It is widely held that boar taint is the result of the accumulation in back-fat of two malodorous compounds: androstenone and skatole. The purpose of the present study was to assess a mass spectrometry-based metabolomics strategy to investigate the metabolic profile of urine samples from pig carcasses presenting low (untainted) and high (tainted) levels of androstenone and skatole in back fat. Urine samples were analyzed by LC-ESI(+)-HRMS. Discrimination between tainted and untainted animals was observed by application of multivariate statistical analysis, which allowed to highlight candidate urinary biomarkers. These urinary metabolites were positively correlated to androstenone and skatole levels in back fat. Therefore, the present study suggested that the measurement of these urinary metabolites might provide information with regard to androstenone and skatole levels in live pigs

Parallel assessment of the effects of bisphenol A and several of its analogs on the adult human testis

International audienceStudy question - Are bisphenol A (BPA) and BPA analogs (BPA-A) safe for male human reproductive function? Summary answer - The endocrine function of human testes explants [assessed by measuring testosterone and insulin-like factor 3 (INSL3)] was impacted by exposure of the human adult testis explants to BPA/BPA-A. What is known already - The few epidemiologic studies performed suggest that bisphenols have potential endocrine disruptive properties, but they did not identify clear and direct patterns of endocrine disruption. Study design, size, duration - Adult human testis explants in culture were exposed to BPA and the analogs bisphenol F (BPF), bisphenol S (BPS), bisphenol E (BPE), bisphenol B (BPB) and bisphenol A diglycidyl ether (BADGE) at 10-9-10-5 M for 24 or 48 h. Participants/materials, setting, methods - Human adult testes were obtained from prostate cancer patients who had no hormone therapy, or from multiorgan donors. After ex vivo exposure to the investigated bisphenols, the measured outcomes were related to histopathology (gross morphology and germ cell viability determined by anti-caspase three immunohistochemistry), and the levels of testosterone, INSL3 and inhibin B were measured using immunoassays. The levels of mRNA encoding key enzymes of bisphenol biotransformation were investigated by quantitative PCR: UGT2B15 UDP (glucuronosyltransferase two family, polypeptide B15), GUSB (glucuronidase beta), SULT1A1 and 3 (sulfotransferase family 1 A member 1 and 3) and STS (steroid sulfatase). Main results and the role of chance - A significant dose-dependent inhibition was found between testosterone levels measured in the culture medium and concentrations of BPA (P = 0.00778 at 24 h and P = 0.0291 at 48 h), BPE (P = 0.039) and BPF (P = 0.00663). The observed BPA and BPA-A-induced inhibition of testosterone production varied according to duration of exposure and BPA/BPA-A concentrations. BPA (10-9 M; P < 0.05), BPB (10-9 M; P < 0.05), BPS (10-9 and 10-8 M; P < 0.05) and BADGE (10-5 M; P < 0.05) increased Leydig cell INSL3 production. By contrast, BPE dose dependently inhibited INSL3 (P = 0.0372). Conversely, Sertoli cell function (inhibin B) and germ cell viability were not significantly affected by either bisphenols. Large scale data - N/A. Limitations, reasons for caution - Environmental compounds cannot be deliberately administered to men, justifying the use of an ex vivo approach. A relatively low number of testes samples were available for analysis (n = 3, except for testosterone secretion with n = 5). The active concentrations of BPA and BPA-A used in the study were higher than those found in human biological fluids. Wider implications of the findings - Under our experimental conditions, direct exposure to BPA or BPA-A can result in endocrine disturbance in the adult human testis. Study funding/competing interest(s) - This study was funded by Inserm (Institut National de la Santé et de la Recherche Médicale), EHESP-School of Public Health, University of Rennes1, by grants from the Agence Nationale de la Recherche (ANR; grant#ANR-13-CESA-0012-03 NEWPLAST) and Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail (ANSES; grant#EST-2010/2/046 (BPATESTIS)). All authors declare they have no current or potential competing financial interests

Assessment of dietary exposure to bisphenol A in the French population with a special focus on risk characterisation for pregnant French women

Bisphenol A (BPA) is used in a wide variety of products and objects for consumers use (digital media such as CD's and DVD's, sport equipment, food and beverage containers, medical equipment). Here, we demonstrate the ubiquitous presence of this contaminant in foods with a background level of contamination of less than 5μg/kg in 85% of the 1498 analysed samples. High levels of contamination (up to 400μg/kg) were found in some foods of animal origin. We used a probabilistic approach to calculate dietary exposure from French individual consumption data for infants under 36months, children and adolescents from 3 to 17years, adults over 18years and pregnant women. The estimated average dietary exposure ranged from 0.12 to 0.14μg/kg body weight per day (bw/d) for infants, from 0.05 to 0.06μg/kg bw/d for children and adolescents, from 0.038 to 0.040μg/kg bw/d for adults and from 0.05 to 0.06μg/kg bw/d for pregnant women. The main sources of exposure were canned foods (50% of the total exposure), products of animal origin (20%) and 30% as a background level. Based on the toxicological values set by the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) for pregnant women, the risk was non negligible. Thus, we simulated scenarios to study the influence of cans and/or food of animal origin on the BPA-related risk for this specific population

An investigation of the endocrine-disruptive effects of bisphenol a in human and rat fetal testes.

International audienc

Effect of BPA exposure on plasma testosterone level and seminal vesicle weight in the host mice xenografted with first trimester human testes and on steroidogenic genes expression in the xenografts.

<p>Human fetal testes (9.1–11.3 GW) were xenografted into castrate Nude (host) mice. Host mice received vehicle (Control) or 10 μM BPA in the drinking water for five weeks. (A) seminal vesicle weight displayed as mean ± SEM (n = 6) on the left panel and as individual values with a line drawn between the control and the corresponding BPA-exposed testis from the same fetus on the right panel. B) plasma testosterone concentration in host mice displayed as mean ± SEM (n = 6) on the left panel and as individual values with a line drawn between the control and the corresponding BPA-exposed testis from the same fetus on the right panel. C) Expression of key genes in the steroidogenic pathway (STAR, CYP11A1, CYP17A1 and CYP19) using quantitative RT-PCR standardized to either β-ACTIN (ACTIN) or RPLP0 or CYPA as endogenous control. Results are presented as a percentage of the control value (mean ± SEM; n = 4). Data analyzed by Wilcoxon test. No significant difference between BPA-treated and control mice were identified.</p

Effect of BPA exposure on testosterone plasma level and seminal vesicle weight in the host mice carrying second trimester human fetal testis xenografts.

<p>Human fetal testes (14-18GW) xenografted into castrated Nude (host) mice. Each human fetal testis was grafted into 1–3 host mice which received the same treatment. Host mice received vehicle (Control), BPA (0.5μg/kg or 50μg/kg/d) daily by oral gavage for five weeks. A) seminal vesicle weight as overall mean ± SEM (n = 4) is displayed on the left with individual values on the right. B) plasma testosterone concentration in host mice as overall mean ± SEM (n = 4) is displayed on the left with individual values on the right. Data analysed by Mann-Whitney test. No significant differences were observed for serum testosterone or seminal vesicle weight between BPA-treated mice compared to control.</p

Effect of BPA exposure on germ cell differentiation in first trimester human fetal testis xenografts.

<p>Human fetal testes (9.1–11.3 GW) were xenografted into castrate Nude (host) mice. Host mice received vehicle (Control) or 10μM BPA in the drinking water for five weeks. (A) Histological sections of testes after immunostaining for AP-2γ (gonocytes). Positive (red arrows) and negative (black arrows) germ cells can be identified. Scale bar: 60 μm. (B) Quantification of AP-2γ-positive cells displayed as mean ± SEM (n = 9) on the left panel and as individual values with a line drawn between the control and the corresponding BPA-treated testis from the same fetus on the right panel. (C) Histological sections of testes after immunostaining for MAGE-A4 (prespermatogonia). Positive (red arrows) and negative (black arrows) germ cells can be identified. Scale bar: 60 μm. (D) Quantification of MAGE-A4-positive cells displayed as mean ± SEM (n = 8) on the left part and as individual values with a line drawn between the control and the corresponding BPA-treated testis from the same fetus on the right part. Data analyzed using the Wilcoxon paired-test. *p<0.05, **p<0.01.</p