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Holmer ML, Zilliacus J, Draskau MK, Hlisníková H, Beronius A, Svingen T. Methodology for developing data-rich Key Event Relationships for Adverse Outcome Pathways exemplified by linking decreased androgen receptor activity with decreased anogenital distance. Reprod Toxicol 2024; 128:108662. [PMID: 38986849 DOI: 10.1016/j.reprotox.2024.108662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/03/2024] [Accepted: 07/06/2024] [Indexed: 07/12/2024]
Abstract
The Adverse Outcome Pathway (AOP) framework has gained widespread acceptance in toxicological disciplines as a tool for aiding chemical hazard assessment. Despite increased activity in AOP development, progress towards a high volume of fully endorsed AOPs has been slow, partly due to the challenging task of constructing complete AOPs according to the AOP Developer's Handbook. To facilitate greater uptake of new knowledge units onto the open-source AOP-wiki platform, a pragmatic approach was recently proposed. This approach involves considering Key Event Relationships (KERs) for individual development through systematic approaches, as they represent essential units of knowledge from which causality can be inferred; from low complexity test data to adverse outcomes in intact organisms. However, more broadly adopted harmonized methodologies for KER development would be desirable. Using the AOP Developer's Handbook as a guide, a KER linking 'decreased androgen receptor (AR) activity' with 'reduced anogenital distance (AGD)' was developed to demonstrate a methodology applicable for future developments of KERs requiring systematic literature retrieval approaches.
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Affiliation(s)
- Marie L Holmer
- National Food Institute, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark.
| | - Johanna Zilliacus
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Monica K Draskau
- National Food Institute, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Henrieta Hlisníková
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Anna Beronius
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Terje Svingen
- National Food Institute, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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2
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Jessl L, Oehlmann J. No effects of the antiandrogens cyproterone acetate (CPA), flutamide and p,p'-DDE on early sexual differentiation but CPA-induced retardation of embryonic development in the domestic fowl ( Gallus gallus domesticus). PeerJ 2023; 11:e16249. [PMID: 37901474 PMCID: PMC10601917 DOI: 10.7717/peerj.16249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/18/2023] [Indexed: 10/31/2023] Open
Abstract
Because a wide range of environmental contaminants are known to cause endocrine disorders in humans and animals, in vivo tests are needed to identify such endocrine disrupting chemicals (EDCs) and to assess their biological effects. Despite the lack of a standardized guideline, the avian embryo has been shown to be a promising model system which responds sensitively to EDCs. After previous studies on the effects of estrogenic, antiestrogenic and androgenic substances, the present work focuses on the effects of in ovo exposure to p,p'-DDE, flutamide and cyproterone acetate (CPA) as antiandrogenic model compounds regarding gonadal sex differentiation and embryonic development of the domestic fowl (Gallus gallus domesticus). The substances were injected into the yolk of fertilized eggs on embryonic day one. On embryonic day 19 sex genotype and phenotype were determined, followed by gross morphological and histological examination of the gonads. Treatment with flutamide (0.5, 5, 50 µg/g egg), p,p'-DDE (0.5, 5, 50 µg/g egg) or CPA (0.2, 2, 20 µg/g egg) did not affect male or female gonad development, assessed by gonad surface area and cortex thickness in both sexes and by the percentage of seminiferous tubules in males as endpoints. This leads to the conclusion that antiandrogens do not affect sexual differentiation during embryonic development of G. gallus domesticus, reflecting that gonads are not target organs for androgens in birds. In ovo exposure to 2 and 20 µg CPA/g egg, however, resulted in significantly smaller embryos as displayed by shortened lengths of skull, ulna and tarsometatarsus. Although gonadal endpoints were not affected by antiandrogens, the embryo of G. gallus domesticus is shown to be a suitable test system for the identification of substance-related mortality and developmental delays.
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Affiliation(s)
- Luzie Jessl
- Aquatic Ecotoxicology, Goethe University Frankfurt, Frankfurt am Main, Hesse, Germany
- R-Biopharm AG, Darmstadt, Hesse, Germany
| | - Jörg Oehlmann
- Aquatic Ecotoxicology, Goethe University Frankfurt, Frankfurt am Main, Hesse, Germany
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3
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Pedersen EB, Christiansen S, Svingen T. AOP key event relationship report: Linking androgen receptor antagonism with nipple retention. Curr Res Toxicol 2022; 3:100085. [PMID: 36090961 PMCID: PMC9459418 DOI: 10.1016/j.crtox.2022.100085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 12/01/2022] Open
Abstract
A full AOP KER description linking AR antagonism with nipple retention in rodents. Described KER 2133 is a non-adjacent KER of an intended AOP delineating anti-androgenicity as a mode for nipple retention. A case study for developing and publishing independent units of information under the AOP framework.
In rat developmental and reproductive toxicity studies, nipple/areola retention (NR) in male offspring is a biomarker for reduced androgen signaling during development. This is because nipples normally regress in male rats in response to androgen signaling during critical stages of development. NR is thus included as a mandatory endpoint in several OECD test guidelines for assessment of chemicals, particularly as a readout for anti-androgenic effects relevant for reproductive toxicity. With the growing interest in developing Adverse Outcome Pathways (AOPs) to aid in chemical risk assessment, a more pragmatic approach has been proposed, whereby essential units of knowledge could be developed independently of complete AOPs, not least emergent key event relationships (KERs). Herein, we have developed a KER linking “androgen receptor antagonism” and “increased areola/nipple retention”. The KER is based on a literature review conducted in a transparent semi-systematic manner in peer-reviewed databases with pre-defined inclusion criteria. Twenty-seven papers were included for development of the KER. The results support a qualitative relationship between the two key events (KEs) with a high weight of evidence; i.e., a causal relationship between androgen receptor (AR) antagonism and nipple retention in male rats exists.
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4
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Schwartz CL, Christiansen S, Hass U, Ramhøj L, Axelstad M, Löbl NM, Svingen T. On the Use and Interpretation of Areola/Nipple Retention as a Biomarker for Anti-androgenic Effects in Rat Toxicity Studies. FRONTIERS IN TOXICOLOGY 2021; 3:730752. [PMID: 35295101 PMCID: PMC8915873 DOI: 10.3389/ftox.2021.730752] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/13/2021] [Indexed: 11/13/2022] Open
Abstract
Areola/nipple retention (NR) is an established biomarker for an anti-androgenic mode of action in rat toxicity studies. It is a mandatory measurement under several OECD test guidelines and is typically assessed in combination with anogenital distance (AGD). Both NR and AGD are considered retrospective biomarkers of insufficient androgen signaling during the masculinization programming window in male fetuses. However, there are still aspects concerning NR as a biomarker for endocrine disruption that remains to be clarified. For instance, can NR be regarded a permanent adverse effect? Is it a redundant measurement if AGD is assessed in the same study? Is NR equally sensitive and specific to anti-androgenic chemical substances as a shortening of male AGD? In this review we discuss these and other aspects concerning the use of NR as a biomarker in toxicity studies. We have collected available literature from rat toxicity studies that have reported on NR and synthesized the data in order to draw a clearer picture about the sensitivity and specificity of NR as an effect biomarker for an anti-androgenic mode of action, including comparisons to AGD measurements. We carefully conclude that NR and AGD in rats for the most part display similar sensitivity and specificity, but that there are clear exceptions which support the continued assessment of both endpoints in relevant reproductive toxicity studies. Available literature also support the view that NR in infant male rats signifies a high risk for permanent nipples in adulthood. Finally, the literature suggests that the mechanisms of action leading from a chemical stressor event to either NR or short AGD in male offspring are overlapping with respect to canonical androgen signaling, yet differ with respect to other mechanisms of action.
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5
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Gray LE, Furr JR, Lambright CS, Evans N, Hartig PC, Cardon MC, Wilson VS, Hotchkiss AK, Conley JM. Quantification of the Uncertainties in Extrapolating From In Vitro Androgen Receptor Antagonism to In Vivo Hershberger Assay Endpoints and Adverse Reproductive Development in Male Rats. Toxicol Sci 2021; 176:297-311. [PMID: 32421828 DOI: 10.1093/toxsci/kfaa067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Multiple molecular initiating events exist that disrupt male sexual differentiation in utero including androgen receptor (AR) antagonism and inhibition of synthesis, and metabolism of fetal testosterone. Disruption of androgen signaling by AR antagonists in utero reduces anogenital distance (AGD) and induces malformations in F1 male rat offspring. We are developing a quantitative network of adverse outcome pathways that includes multiple molecular initiating events and key events linking anti-AR activities to permanent reproductive abnormalities. Here, our objective was to determine how accurately the EC50s for AR antagonism in vitro or ED50s for reduced tissue growth in the Hershberger assay (HA) (key events in the adverse outcome pathway) predict the ED50s for reduced AGD in male rats exposed in utero to AR antagonists. This effort included in-house data and published studies from the last 60 years on AR antagonism in vitro and in vivo effects in the HA and on AGD after in utero exposure. In total, more than 250 studies were selected and included in the analysis with data from about 60 potentially antiandrogenic chemicals. The ability to predict ED50s for key events and adverse developmental effects from the in vitro EC50s displays considerable uncertainty with R2 values for HA and AGD of < 6%. In contrast, there is considerably less uncertainty in extrapolating from the ED50s in the HA to the ED50s for AGD (R2 value of about 85%). In summary, the current results suggest that the key events measured in the HA can be extrapolated with reasonable certainty to predict the ED50s for the adverse in utero effects of antiandrogenic chemicals on male rat offspring.
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Affiliation(s)
- Leon E Gray
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | | | - Christy S Lambright
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Nicola Evans
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Phillip C Hartig
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Mary C Cardon
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Vickie S Wilson
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Andrew K Hotchkiss
- HPASB, HEEAD, CPHEA, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Justin M Conley
- Reproductive and Developmental Toxicology Branch, PHITD, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
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Schreiber E, Garcia T, González N, Esplugas R, Sharma RP, Torrente M, Kumar V, Bovee T, Katsanou ES, Machera K, Domingo JL, Gómez M. Maternal exposure to mixtures of dienestrol, linuron and flutamide. Part I: Feminization effects on male rat offspring. Food Chem Toxicol 2020; 139:111256. [DOI: 10.1016/j.fct.2020.111256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/06/2020] [Accepted: 03/08/2020] [Indexed: 12/23/2022]
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7
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Gray LE, Furr JR, Conley JM, Lambright CS, Evans N, Cardon MC, Wilson VS, Foster PM, Hartig PC. A Conflicted Tale of Two Novel AR Antagonists In Vitro and In Vivo: Pyrifluquinazon Versus Bisphenol C. Toxicol Sci 2020; 168:632-643. [PMID: 30649549 DOI: 10.1093/toxsci/kfz010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Chemicals that disrupt androgen receptor (AR) function in utero induce a cascade of adverse effects in male rats including reduced anogenital distance, retained nipples, and reproductive tract malformations. The objective of this study was to compare the in vitro and in utero activities of two novel AR antagonists, bisphenol C (BPC) and pyrifluquinazon (PFQ). In vitro, BPC was as potent an AR antagonist as hydroxyflutamide. Furthermore, BPC inhibited fetal testis testosterone production and testis gene expression ex vivo. However, when BPC was administered at 100 and 200 mg/kg/d in utero, the reproductive tract of the male offspring was minimally affected. None of the males displayed reproductive malformations. For comparison, in utero administration of flutamide has been shown to induce malformations in 100% of males at 6 mg/kg/d. In vitro, PFQ was several orders of magnitude less potent than BPC, vinclozolin, or procymidone. However, in utero administration of 12.5, 25, 50, and 100 mg PFQ/kg/d on GD 14-18 induced antiandrogenic effects at all dosage levels and 91% of the males displayed reproductive malformation in the high dose group. Overall, BPC was ∼380-fold more potent than PFQ in vitro, whereas PFQ was far more potent than BPC in utero. Incorporating toxicokinetic and toxicodynamic data into in vitro to in vivo extrapolations would reduce the discordance between the in vitro and in utero effects of PFQ and BPC and combining in vitro results with a short-term Hershberger assay would reduce the uncertainty in predicting the in utero effects of antiandrogenic chemicals.
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Affiliation(s)
- Leon Earl Gray
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | | | - Justin M Conley
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Christy S Lambright
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Nicola Evans
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Mary C Cardon
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | - Vickie S Wilson
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
| | | | - Phillip C Hartig
- Reproductive Toxicology Branch, Toxicology Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (U.S. EPA), Research Triangle Park, North Carolina 27711
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8
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Zacharia LC. Permitted Daily Exposure of the Androgen Receptor Antagonist Flutamide. Toxicol Sci 2018; 159:279-289. [PMID: 28666357 DOI: 10.1093/toxsci/kfx135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This report aims to determine the permitted daily exposure (PDE) of flutamide, an androgen receptor blocker, as directed by guideline EMA/CHMP/CVPM/SWP/169430/2012 that came into effect on June 2015. A literature review was conducted to identify toxicity studies of flutamide. Hazards and sensitive endpoints were determined. Based on the no adverse effect levels (NOAELs) and lowest observed adverse effect levels (LOAELs) reported from both reproductive, developmental, and 28-day toxicity studies the PDE was calculated. Most of the toxicity studies converge toward a NOAEL of 1 mg/kg/d that translates to a PDE of 0.1 mg/d. However, taking into consideration the worst case scenarios for additional safety a PDE of 0.025 mg/d (25 μg/d) was calculated based on a reported NOAEL of 0.25 mg/kg/d. A PDE of 0.05 mg/d (50 μg/d) was also calculated from reproductive/developmental toxicity studies, which is in close agreement with the PDE from the 28-day toxicity studies. Considering the lowest PDE of 0.025 mg/d, residual flutamide at this dose is unlikely to pose any risk to humans. Nonmonotonic dose response (NMDR) effects of flutamide were not supported by literature. Oral route of administration was considered.
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Affiliation(s)
- Lefteris C Zacharia
- Department of Life and Health Sciences, School of Sciences and Engineering, University of Nicosia, 1700 Nicosia, Cyprus
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9
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Conley JM, Lambright CS, Evans N, Cardon M, Furr J, Wilson VS, Gray LE. Mixed "Antiandrogenic" Chemicals at Low Individual Doses Produce Reproductive Tract Malformations in the Male Rat. Toxicol Sci 2018; 164:166-178. [PMID: 29945228 PMCID: PMC6677127 DOI: 10.1093/toxsci/kfy069] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Biomonitoring efforts have clearly shown that all humans are exposed to chemical mixtures. Of concern is whether or not exposure to mixtures during pregnancy contributes to congenital abnormalities in children even when each chemical is at an individual dose that does not affect the fetus. Here, we hypothesized that in utero exposure to a mixture of chemicals covering multiple "antiandrogenic" mechanisms of action at doses that individually have no adverse effect would result in permanent reproductive tract alterations in the male rat after birth. Pregnant dams were exposed to a range of dilutions (100%, 50%, 25%, 12.5%, 6.25%, or vehicle control) of a mixture containing pesticides, phthalates, and drugs (p, p'-DDE, linuron, prochloraz, procymidone, pyrifluquinazon, vinclozolin, finasteride, flutamide, simvastatin, and 9 phthalates [dipentyl, dicyclohexyl, di-2-ethylhexyl, dibutyl, benzyl butyl, diisobutyl, diisoheptyl, dihexyl, and diheptyl]). The top dose contained each chemical at 20% of its lowest observed adverse effect level (LOAEL) for the most sensitive male reproductive alteration following in utero exposure. We found that male rat offspring displayed a variety of neonatal, pubertal, and permanent adult effects across all dose levels. Even at the lowest dose (each chemical approximately 80-fold below lowest observed adverse effect level) there were permanent reductions in several reproductive tract tissue weights. In the top dose group, 100% of male offspring displayed permanent severe birth defects including genital malformations. Despite acting via 5 different molecular initiating events, a mixture of 18 chemicals can combine to produce additive effects even when each compound is at is at a relatively low dose.
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Affiliation(s)
- Justin M. Conley
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
| | - Christy S. Lambright
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
| | - Nicki Evans
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
| | - Mary Cardon
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
| | - Johnathan Furr
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
- Southern Research, Birmingham, AL 35205
| | - Vickie S. Wilson
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
| | - L. Earl Gray
- U.S. Environmental Protection Agency/Office of Research & Development/National Health and Environmental Effects Research Laboratory/Toxicity Assessment Division, Research Triangle Park, NC 27711
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10
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Dere E, Anderson LM, Huse SM, Spade DJ, McDonnell-Clark E, Madnick SJ, Hall SJ, Camacho L, Lewis SM, Vanlandingham MM, Boekelheide K. Effects of continuous bisphenol A exposure from early gestation on 90 day old rat testes function and sperm molecular profiles: A CLARITY-BPA consortium study. Toxicol Appl Pharmacol 2018; 347:1-9. [PMID: 29596923 DOI: 10.1016/j.taap.2018.03.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/28/2018] [Accepted: 03/19/2018] [Indexed: 12/17/2022]
Abstract
Bisphenol A (BPA) is a ubiquitous industrial chemical that has been identified as an endocrine disrupting compound (EDC). There is growing concern that early life exposures to EDCs, such as BPA, can adversely affect the male reproductive tract and function. This study was conducted as part of the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA) to further delineate the toxicities associated with continuous exposure to BPA from early gestation, and to comprehensively examine the elicited effects on testes and sperm. NCTR Sprague Dawley rat dams were gavaged from gestational day (GD) 6 until parturition, and their pups were directly gavaged daily from postnatal day (PND) 1 to 90 with BPA (2.5, 25, 250, 2500, 25,000, 250,000 μg/kg/d) or vehicle control. At PND 90, the testes and sperm were collected for evaluation. The testes were histologically evaluated for altered germ cell apoptosis, sperm production, and altered spermiation. RNA and DNA isolated from sperm were assessed for elicited changes in global mRNA transcript abundance and altered DNA methylation. Effects of BPA were observed in changes in body, testis and epididymis weights only at the highest administered dose of BPA of 250,000 μg/kg/d. Genome-wide transcriptomic and epigenomic analyses failed to detect robust alterations in sperm mRNA and DNA methylation levels. These data indicate that prolonged exposure starting in utero to BPA over a wide range of levels has little, if any, impact on the testes and sperm molecular profiles of 90 day old rats as assessed by the histopathologic, morphometric, and molecular endpoints evaluated.
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Affiliation(s)
- Edward Dere
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States; Division of Urology, Rhode Island Hospital, Providence, RI, United States
| | - Linnea M Anderson
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Susan M Huse
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Daniel J Spade
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | | | - Samantha J Madnick
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Susan J Hall
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States
| | - Luísa Camacho
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR, United States
| | - Sherry M Lewis
- Office of Scientific Coordination, National Center for Toxicological Research, Jefferson, AR, United States
| | - Michelle M Vanlandingham
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR, United States
| | - Kim Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States.
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11
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Schneider S, Fussell KC, Melching-Kollmuss S, Buesen R, Gröters S, Strauss V, Jiang X, van Ravenzwaay B. Investigations on the dose-response relationship of combined exposure to low doses of three anti-androgens in Wistar rats. Arch Toxicol 2017; 91:3961-3989. [PMID: 28879601 PMCID: PMC5719133 DOI: 10.1007/s00204-017-2053-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/28/2017] [Indexed: 02/08/2023]
Abstract
The current investigation examines whether combined exposure to three anti-androgens (flutamide, prochloraz, vinclozolin) result in interference with endocrine homeostasis when applied at very low dose levels, and whether the results of combined exposure are more pronounced than to the individual compounds. A pre-post-natal in vivo study design was chosen with more parameters than regulatory testing protocols require (additional endpoints addressing hormone levels, morphology and histopathological examinations). Dose levels were chosen to represent the lowest observed adverse effect level (LOAEL), the no observed adverse effect level (NOAEL), and the acceptable daily intake for each individual substance. Anti-androgenic changes were observable at the effect level (LOAEL) but not at lower exposures. Nipple/areola counts appeared to be a sensitive measure of effect, in addition to male sex organ weights at sexual maturation, and finally gross findings. The results indicate the absence of evidence for effects at low or very low dose levels. No (adverse) effects were seen at the NOAEL dose. A non-monotonic dose-response relationship was not evident. Combined exposure at LOAEL level resulted in enhanced responses for anogenital index, number of areolas/nipples, delayed preputial separation and reduced ventral prostate weight in comparison to the individual compounds.
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Affiliation(s)
- Steffen Schneider
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | | | | | - Roland Buesen
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Sibylle Gröters
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Volker Strauss
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Xiaoqi Jiang
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
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12
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Marin-Kuan M, Fussell KC, Riederer N, Latado H, Serrant P, Mollergues J, Coulet M, Schilter B. Differentiating true androgen receptor inhibition from cytotoxicity-mediated reduction of reporter-gene transactivation in-vitro. Toxicol In Vitro 2017; 45:359-365. [PMID: 28377212 DOI: 10.1016/j.tiv.2017.03.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/17/2017] [Accepted: 03/30/2017] [Indexed: 12/22/2022]
Abstract
In vitro effect-based reporter assays are applied as biodetection tools designed to address nuclear receptor mediated-modulation. While such assays detect receptor modulating potential, cell viability needs to be addressed, preferably in the same well. Some assays circumvent this by co-transfecting a second constitutively-expressed marker gene or by multiplexing a cytotoxicity assay. Some assays, such as the CALUX®, lack this feature. The cytotoxic effects of unknown substances can confound in vitro assays, making the interpretation of results difficult and uncertain, particularly when assessing antagonistic activity. It's necessary to determine whether the cause of the reporter signal decrease is an antagonistic effect or a non-specific cytotoxic effect. To remedy this, we assessed the suitability of multiplexing a cell viability assay within the CALUX® transcriptional activation test for anti-androgenicity. Tests of both well-characterized anti-androgens and cytotoxic compounds demonstrated the suitability of this approach for discerning between the molecular mechanisms of action without altering the nuclear receptor assay; though some compounds were both cytotoxic and anti-androgenic. The optimized multiplexed assay was then applied to an uncharacterized set of polycyclic aromatic compounds. These results better characterized the mode of action and the classification of effects. Overall, the multiplexed protocol added value to CALUX test performance.
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Affiliation(s)
- Maricel Marin-Kuan
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland.
| | - Karma C Fussell
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Nicolas Riederer
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Helia Latado
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Patrick Serrant
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Julie Mollergues
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Myriam Coulet
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
| | - Benoit Schilter
- Chemical Food Safety, Nestlé Research Centre, P.O. Box 44, CH-1000 Lausanne 26, Switzerland
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13
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Parrott JL, Bjerregaard P, Brugger KE, Gray LE, Iguchi T, Kadlec SM, Weltje L, Wheeler JR. Uncertainties in biological responses that influence hazard and risk approaches to the regulation of endocrine active substances. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2017; 13:293-301. [PMID: 27862884 PMCID: PMC8215718 DOI: 10.1002/ieam.1866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/19/2016] [Accepted: 11/09/2016] [Indexed: 05/18/2023]
Abstract
Endocrine-disrupting substances (EDS) may have certain biological effects including delayed effects, multigenerational effects, and may display nonmonotonic dose-response (NMDR) relationships that require careful consideration when determining environmental hazards. Endocrine disrupting substances can have specific and profound effects when exposure occurs during sensitive windows of the life cycle (development, reproduction). This creates the potential for delayed effects that manifest when exposure has ceased, possibly in a different life stage. This potential underscores the need for testing in appropriate (sensitive) life stages and full life cycle designs. Such tests are available in the Organisation for Economic Co-operation and Development (OECD) tool box and should be used to derive endpoints that can be considered protective of all life stages. Similarly, the potential for effects to be manifest in subsequent generations (multigenerational effects) has also been raised as a potential issue in the derivation of appropriate endpoints for EDS. However, multigenerational studies showing increasing sensitivity of successive generations are uncommon. Indeed this is reflected in the design of new higher tier tests to assess endocrine active substances (EAS) that move to extended one-generation designs and away from multi-generational studies. The occurrence of NMDRs is also considered a limiting factor for reliable risk assessment of EDS. Evidence to date indicates NMDRs are more prevalent in in vitro and mechanistic data, not often translating to adverse apical endpoints that would be used in risk assessment. A series of steps to evaluate NMDRs in the context of endocrine hazard and risk assessment procedures is presented. If careful consideration of delayed, multigenerational effects and NMDRs is made, it is feasible to assess environmental endocrine hazards and derive robust apical endpoints for risk assessment procedures ensuring a high level of environmental protection. Integr Environ Assess Manag 2017;13:293-301. © 2016 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Joanne L Parrott
- Environment and Climate Change Canada, Burlington, Ontario, Canada
- Address correspondence to
| | - Poul Bjerregaard
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Kristin E Brugger
- DuPont Crop Protection, Stine-Haskell Research Center, Newark, New Jersey, USA
| | - L Earl Gray
- USEPA, Reproductive Toxicology Branch, Office of Research and Development, Research Triangle Park, North Carolina
| | - Taisen Iguchi
- Department of Bioenvironmental Research, Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Japan
| | - Sarah M Kadlec
- University of Minnesota, Integrated Biosciences Graduate Program, Duluth, Minnesota, USA
| | - Lennart Weltje
- BASF SE, Crop Protection-Ecotoxicology, Limburgerhof, Germany
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14
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Flick B, Schneider S, Melching-Kollmuss S, Fussell KC, Gröters S, Buesen R, Strauss V, van Ravenzwaay B. Investigations of putative reproductive toxicity of low-dose exposures to vinclozolin in Wistar rats. Arch Toxicol 2016; 91:1941-1956. [PMID: 27612472 DOI: 10.1007/s00204-016-1811-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 08/04/2016] [Indexed: 01/11/2023]
Abstract
The current investigation examines whether the fungicide vinclozolin, which has an anti-androgenic mode of action, is capable of disrupting endocrine homeostasis at very low doses. The data generated clarify whether a non-monotonic dose-response relationship exists to enhance the current debate about the regulation of endocrine disruptors. Moreover, it is part of a series of investigations assessing the dose-response relationship of single and combined administration of anti-androgenic substances. A pre-postnatal in vivo study design was chosen which was compliant with regulatory testing protocols. The test design was improved by additional endpoints addressing hormone levels, morphology and histopathological examinations. Doses were chosen to represent an effect level (20 mg/kg bw/d), the current NOAEL (4 mg/kg bw/d), and a dose close to the "ADI" (0.005 mg/kg bw/d) for the detection of a possible non-monotonic dose-response curve. Anti-androgenic changes were observable at the effect level but not at lower exposures. Nipple/areola counts appeared to be the most sensitive measure of effect, followed by male sex organ weights at sexual maturation, and finally gross and histopathological findings. The results indicate the absence of evidence for effects at low or very low dose levels. A non-monotonic dose-response relationship was not evident.
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Affiliation(s)
- Burkhard Flick
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Steffen Schneider
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | | | | | - Sibylle Gröters
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Roland Buesen
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
| | - Volker Strauss
- Experimental Toxicology and Ecology, BASF SE, 67056, Ludwigshafen, Germany
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15
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Arfi A, Cohen J, Canlorbe G, Bendifallah S, Thomassin-Naggara I, Darai E, Benachi A, Arfi JS. First-trimester determination of fetal gender by ultrasound: measurement of the ano-genital distance. Eur J Obstet Gynecol Reprod Biol 2016; 203:177-81. [PMID: 27323318 DOI: 10.1016/j.ejogrb.2016.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 02/01/2023]
Abstract
INTRODUCTION Early ultrasound fetal sex determination is of obvious interest, particularly in the context of X-linked diseases. In the human, the anogenital distance, i.e., the distance between the caudal end and the base of the genital tubercule is sexually dimorphic. This difference is apparent from 11 weeks of gestation. The aim of this prospective study was to evaluate the accuracy of anogenital distance measurement during the first trimester ultrasound in the early determination of fetal gender. MATERIALS AND METHODS Fetal gender was assessed by ultrasound in 310 singleton pregnancies at 11-14 weeks of gestation. The optimal cut-off was determined by the minimal p-value technic and validated using bootstrap simulation. RESULTS 310 women were included. A cut-off of 4.8mm was determined to predict male (≥4.8mm) or female (<4.8mm) fetuses. Sex was correctly determined for 87% of the males and 89% of the females. The inter-observer variability was excellent. CONCLUSION This study presents a new sonographic sign for early fetal sex determination that has not been previously explored. It appears to be an accurate tool but it requires further validation in larger series.
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Affiliation(s)
- A Arfi
- Department of Obstetrics, Gynecology and Reproductive Medicine, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, GRC 6-UPMC Centre Expert en Endométriose (C3E), France.
| | - J Cohen
- Department of Obstetrics, Gynecology and Reproductive Medicine, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, GRC 6-UPMC Centre Expert en Endométriose (C3E), France
| | - G Canlorbe
- Department of Obstetrics, Gynecology and Reproductive Medicine, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, GRC 6-UPMC Centre Expert en Endométriose (C3E), France
| | - S Bendifallah
- Department of Obstetrics, Gynecology and Reproductive Medicine, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, GRC 6-UPMC Centre Expert en Endométriose (C3E), France; ISERM UMRS 707, « Epidemiology, Information systems, Modeling », University Pierre and Marie Curie, Paris, France
| | - I Thomassin-Naggara
- Department of Radiology, Tenon Hospital, AP-HP, Paris, France; GRC6-UPMC: Centre expert en Endométriose (C3E), Paris, France; UMR_S938 Université Pierre et Marie Curie Paris 6, Paris, France
| | - E Darai
- Department of Obstetrics, Gynecology and Reproductive Medicine, Hôpital Tenon, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, GRC 6-UPMC Centre Expert en Endométriose (C3E), France
| | - A Benachi
- Department of Obstetrics, Gynecology and Reproductive Medicine and Centre Maladies Rares, Hernie de Coupole Diaphragmatique, Hôpital Antoine Béclère, APHP, Université Paris Sud, Clamart, France
| | - J S Arfi
- Department of Obstetrics and gynecology, Hôpital Armand Trousseau, Assistance Publique des Hôpitaux de Paris, Université Pierre et Marie Curie Paris 6, France
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16
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Comparing effect levels of regulatory studies with endpoints derived in targeted anti-androgenic studies: example prochloraz. Arch Toxicol 2016; 91:143-162. [DOI: 10.1007/s00204-016-1678-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/28/2016] [Indexed: 01/05/2023]
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