1
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Teuschler LK, Hertzberg RC, McDonald A, Sey YM, Simmons JE. Evaluation of a Proportional Response Addition Approach to Mixture Risk Assessment and Predictive Toxicology Using Data on Four Trihalomethanes from the U.S. EPA's Multiple-Purpose Design Study. Toxics 2024; 12:240. [PMID: 38668462 PMCID: PMC11053411 DOI: 10.3390/toxics12040240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
In this study, proportional response addition (Prop-RA), a model for predicting response from chemical mixture exposure, is demonstrated and evaluated by statistically analyzing data on all possible binary combinations of the four regulated trihalomethanes (THMs). These THMs were the subject of a multipurpose toxicology study specifically designed to evaluate Prop-RA. The experimental design used a set of doses common to all components and mixtures, providing hepatotoxicity data on the four single THMs and the binary combinations. In Prop-RA, the contribution of each component to mixture toxicity is proportional to its fraction in the mixture based on its response at the total mixture dose. The primary analysis consisted of 160 evaluations. Statistically significant departures from the Prop-RA prediction were found for seven evaluations, with three predications that were greater than and four that were less than the predicted response; interaction magnitudes (n-fold difference in response vs. prediction) ranged from 1.3 to 1.4 for the former and 2.6 to 3.8 for the latter. These predictions support the idea that Prop-RA works best with chemicals where the effective dose ranges overlap. Prop-RA does not assume the similarity of toxic action or independence, but it can be applied to a mixture of components that affect the same organ/system, with perhaps unknown toxic modes of action.
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Affiliation(s)
| | | | - Anthony McDonald
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Yusupha Mahtarr Sey
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Jane Ellen Simmons
- Public Health and Integrated Toxicology Division, Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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2
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Gray LE, Conley JM, Bursian SJ. Dose Addition Models Accurately Predict the Subacute Effects of a Mixture of Perfluorooctane Sulfonate and Perfluorooctanoic Acid on Japanese Quail (Coturnix japonica) Chick Mortality. Environ Toxicol Chem 2024; 43:97-104. [PMID: 37753878 DOI: 10.1002/etc.5758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/03/2023] [Accepted: 09/26/2023] [Indexed: 09/28/2023]
Abstract
Biomonitoring data have consistently demonstrated that fish, wildlife, and humans are exposed to multiple per- and polyfluoroalkyl substances (PFAS) in drinking water and foods. Despite ubiquitous exposure to mixtures of PFAS, there is a lack of in vivo PFAS mixture research that addresses whether these chemicals act in a cumulative, dose-additive (DA) manner or whether they behave independently. For this reason, there is a critical need for mixtures studies designed to evaluate the cumulative toxicity and potential chemical interactions to support the assessment of human and ecological risks and also to define appropriate regulatory actions. Our primary objective was to evaluate the previously published Japanese quail chick mortality concentration-response data for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and the mixture of PFOS + PFOA and to use statistical modeling to determine whether the effects of the mixtures were accurately predicted by either DA or response addition modeling. In addition, we wanted to compare different DA models to determine whether one model produced more accurate predictions than the others. Our results support the hypothesis of cumulative effects on shared endpoints from PFOA and PFOS co-exposure and DA approaches for predictive estimates of cumulative effects. Given the limited number of in vivo studies that have been executed with enough individual PFAS and PFAS mixture concentration-response data to test the hypothesis of DA for PFAS mixtures, this re-analysis of the data is an important contribution to our understanding of how PFAS mixtures act. The analysis will provide support for regulatory agencies as they begin to implement PFAS cumulative hazard assessments in higher vertebrates. Environ Toxicol Chem 2024;43:97-104. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- L Earl Gray
- US Environmental Protection Agency, Office of Research & Development, Center for Public Health and Environmental Assessment, Office of Research & Development, US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Justin M Conley
- US Environmental Protection Agency, Office of Research & Development, Center for Public Health and Environmental Assessment, Office of Research & Development, US Environmental Protection Agency, Research Triangle Park, North Carolina
| | - Steven J Bursian
- Department of Animal Science, Michigan State University, East Lansing, Michigan, USA
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3
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Conley JM, Lambright CS, Evans N, Medlock-Kakaley E, Dixon A, Hill D, McCord J, Strynar MJ, Ford J, Gray LE. Cumulative maternal and neonatal effects of combined exposure to a mixture of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) during pregnancy in the Sprague-Dawley rat. Environ Int 2022; 170:107631. [PMID: 36402036 PMCID: PMC9944680 DOI: 10.1016/j.envint.2022.107631] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/29/2022] [Accepted: 11/10/2022] [Indexed: 05/10/2023]
Abstract
Globally, biomonitoring data demonstrate virtually all humans carry residues of multiple per- and polyfluoroalkyl substances (PFAS). Despite pervasive co-exposure, limited mixtures-based in vivo PFAS toxicity research has been conducted. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are commonly detected PFAS in human and environmental samples and both produce adverse effects in laboratory animal studies, including maternal and offspring effects when orally administered during pregnancy and lactation. To evaluate the effects of combined exposure to PFOA and PFOS, we orally exposed pregnant Sprague-Dawley rats from gestation day 8 (GD8) to postnatal day 2 (PND2) to PFOA (10-250 mg/kg/d) or PFOS (0.1-5 mg/kg/d) individually to characterize effects and dose response curve parameters, followed by a variable-ratio mixture experiment with a constant dose of PFOS (2 mg/kg/d) mixed with increasing doses of PFOA (3-80 mg/kg/d). The mixture study design was intended to: 1) shift the PFOA dose response curves for endpoints shared with PFOS, 2) allow comparison of dose addition (DA) and response addition (RA) model predictions, 3) conduct relative potency factor (RPF) analysis for multiple endpoints, and 4) avoid overt maternal toxicity. Maternal serum and liver concentrations of PFOA and PFOS were consistent between the individual chemical and mixture experiments. Combined exposure with PFOS significantly shifted the PFOA dose response curves towards effects at lower doses compared to PFOA-only exposure for multiple endpoints and these effects were well predicted by dose addition. For endpoints amenable to mixture model analyses, DA produced equivalent or better estimates of observed data than RA. All endpoints evaluated were accurately predicted by RPF and DA approaches except for maternal gestational weight gain, which produced less-than-additive results in the mixture. Data support the hypothesis of cumulative effects on shared endpoints from PFOA and PFOS co-exposure and dose additive approaches for predictive estimates of mixture effects.
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Affiliation(s)
- Justin M Conley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Christy S Lambright
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Nicola Evans
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Elizabeth Medlock-Kakaley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Aaron Dixon
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - Donna Hill
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
| | - James McCord
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Environmental Measurement and Modeling, Research Triangle Park, NC, USA.
| | - Mark J Strynar
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Environmental Measurement and Modeling, Research Triangle Park, NC, USA.
| | - Jermaine Ford
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Computational Toxicology and Exposure, Research Triangle Park, NC, USA.
| | - L Earl Gray
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment, Research Triangle Park, NC, USA.
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4
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Hou P, Dai W, Jin Y, Zhao F, Liu J, Liu H. Maternal exposure to di-2-ethylhexyl phthalate (DEHP) depresses lactation capacity in mice. Sci Total Environ 2022; 837:155813. [PMID: 35550907 DOI: 10.1016/j.scitotenv.2022.155813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/20/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Increasing evidence shows that di-2-ethylhexyl phthalate (DEHP), mostly commonly used phthalate for the production of flexible polyvinyl chloride (PVC), has the potential to induce serious health risks in humans. However, the understanding of DEHP-induced lactation performance remains largely unknown. We sought to investigate the adverse effects of DEHP on lactation and examine the underlying mechanism linking DEHP exposure with the lactation alterations. We successfully adapted a maternal DEHP exposure model in female pregnant/lactating mice. Then we determined effects of DEHP exposure on food intake, body weight and milk production as well as the alterations in endocrine factors in lactating mice. The integrated metabonomic and transcriptomic analyses of the mammary gland were performed to measure the changed metabolites and genes related to DEHP exposure-induced lactation alterations. We observed the reduced food intake with elevated blood leptin and the decreased milk yield as well as the reduced levels of serum prolactin, growth hormone, insulin-like growth factor 1 and insulin after exposed to DEHP. Furthermore, 208 metabolites and 3452 genes were separately identified as differentially expressed features associated with DEHP exposure. Integrated metabonomic and transcriptomic analyses demonstrated that DEHP caused lactation depression mainly through impairing energy generation, inducing stress responses along with the hypoactivation of inflammation, reducing the production of antioxidants, disrupting hormone homeostasis and repressing the synthesis of milk constituents (the lower glucose availability for lactose synthesis; the disruption of milk fat globule membrane for lipid droplet formation; the ribosomal dysfunction and disruption of post-modifications for milk protein synthesis). We demonstrated that DEHP disrupted several lactation-related hormone homeostasis and multiple processes like energy insufficiency, inflammation activation, oxidative stress aggravation and disturbance of milk production in the mammary gland of female lactating mice. Our results provide valuable information for the health risk of plastic additive (DEHP) on female lactation dysfunction.
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Affiliation(s)
- Pengfei Hou
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenting Dai
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yanshan Jin
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Fengqi Zhao
- Laboratory of Lactation and Metabolic Physiology, Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT, USA
| | - Jianxin Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongyun Liu
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
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5
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Elcombe CS, Monteiro A, Elcombe MR, Ghasemzadeh-Hasankolaei M, Sinclair KD, Lea R, Padmanabhan V, Evans NP, Bellingham M. Developmental exposure to real-life environmental chemical mixture programs a testicular dysgenesis syndrome-like phenotype in prepubertal lambs. Environ Toxicol Pharmacol 2022; 94:103913. [PMID: 35738462 PMCID: PMC9554787 DOI: 10.1016/j.etap.2022.103913] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 05/30/2023]
Abstract
Current declines in male reproductive health may, in part, be driven by anthropogenic environmental chemical (EC) exposure. Using a biosolids treated pasture (BTP) sheep model, this study examined the effects of gestational exposure to a translationally relevant EC mixture. Testes of 8-week-old ram lambs from mothers exposed to BTP during pregnancy contained fewer germ cells and had a greater proportion of Sertoli-cell-only seminiferous tubules. This concurs with previous published data from fetuses and neonatal lambs from mothers exposed to BTP. Comparison between the testicular transcriptome of biosolids lambs and human testicular dysgenesis syndrome (TDS) patients indicated common changes in genes involved in apoptotic and mTOR signalling. Gene expression data and immunohistochemistry indicated increased HIF1α activation and nuclear localisation in Leydig cells of BTP exposed animals. As HIF1α is reported to disrupt testosterone synthesis, these results provide a potential mechanism for the pathogenesis of this testicular phenotype, and TDS in humans.
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Affiliation(s)
- Chris S Elcombe
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK; School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
| | - Ana Monteiro
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Matthew R Elcombe
- MicroMatrices Associates Ltd, Dundee Technopole, James Lindsay Place, Dundee, UK
| | - Mohammad Ghasemzadeh-Hasankolaei
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Kevin D Sinclair
- University of Nottingham, Sutton Bonington Campus, Loughborough, UK
| | - Richard Lea
- University of Nottingham, Sutton Bonington Campus, Loughborough, UK
| | | | - Neil P Evans
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Michelle Bellingham
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
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6
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Elcombe CS, Evans NP, Bellingham M. Critical review and analysis of literature on low dose exposure to chemical mixtures in mammalian in vivo systems. Crit Rev Toxicol 2022; 52:221-238. [PMID: 35894754 PMCID: PMC9530410 DOI: 10.1080/10408444.2022.2091423] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Anthropogenic chemicals are ubiquitous throughout the environment. Consequentially, humans are exposed to hundreds of anthropogenic chemicals daily. Current chemical risk assessments are primarily based on testing individual chemicals in rodents at doses that are orders of magnitude higher than that of human exposure. The potential risk from exposure to mixtures of chemicals is calculated using mathematical models of mixture toxicity based on these analyses. These calculations, however, do not account for synergistic or antagonistic interactions between co-exposed chemicals. While proven examples of chemical synergy in mixtures at low doses are rare, there is increasing evidence that, through non-conformance to current mixture toxicity models, suggests synergy. This review examined the published studies that have investigated exposure to mixtures of chemicals at low doses in mammalian in vivo systems. Only seven identified studies were sufficient in design to directly examine the appropriateness of current mixture toxicity models, of which three showed responses significantly greater than additivity model predictions. While the remaining identified studies were unable to provide evidence of synergistic toxicity, it became apparent that many results of such studies were not always explicable by current mixture toxicity models. Additionally, two data gaps were identified. Firstly, there is a lack of studies where individual chemical components of a complex mixture (>10 components) are tested in parallel to the chemical mixture. Secondly, there is a lack of dose-response data for mixtures of chemicals at low doses. Such data is essential to address the appropriateness and validity of future chemical mixture toxicity models.
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Affiliation(s)
- Chris S Elcombe
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.,School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Neil P Evans
- Institute of Biodiversity Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Michelle Bellingham
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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7
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Gray LE, Conley JM, Lambright CS, Furr JR. In utero exposure to a mixture of the perfluoroalkyl-isopropyl pesticide pyrifluquinazon with dibutyl phthalate cumulatively disrupts male rat reproductive development via different mechanisms of action. Toxicol Sci 2022; 188:234-247. [PMID: 35642937 PMCID: PMC10269475 DOI: 10.1093/toxsci/kfac059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Administration of individual chemicals and mixtures during sexual differentiation that disrupt the androgen signaling pathway can induce reproductive abnormalities in male rats. In the current study, we co-administered the heptafluoroisopropyl pesticide pyrifluquinazon (PFQ), and dibutyl phthalate (DBP) to pregnant rats during sexual differentiation of the reproductive tract. Both chemicals have been shown to disrupt reproductive tract differentiation in a dose-related manner reducing male anogenital distance (AGD), permanently reducing androgen-dependent tissue weights and sperm counts, and inducing reproductive malformations in male offspring, albeit by different mechanisms of action that converge downstream in the androgen signaling pathway on a common key event. Rats were orally dosed from gestation days 14-18 with dilutions of PFQ and DBP at 0, 12.5, 25, 50, 75 and 100% of the top dose (100 mg/kg PFQ and 750 mg/kg DBP). The mixture ratio was selected such that each chemical would contribute equally to multiple effects on the male offspring reproductive tract and the dose range was designed to determine if the mixture produced additive effects predicted by dose addition or response addition models, or whether significant interactions occurred. Observed data were compared to dose and response addition model predictions. As hypothesized, the mixture reduced F1 male AGD, reproductive organ weights and sperm counts and induced hypospadias with dose addition consistently providing a better prediction of the observed effects than response addition. These results support our hypothesis that chemicals that disrupt the androgen signaling pathway induce dose-additive male reproductive abnormalities regardless of the specific mechanism of action.
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Affiliation(s)
- L Earl Gray
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, Research Triangle Park, 27711 North Carolina
| | - Justin M Conley
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, Research Triangle Park, 27711 North Carolina
| | - Christy S Lambright
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, Research Triangle Park, 27711 North Carolina
| | - Johnathan R Furr
- Inotiv, 13 Firstfield Road, Suite 110, Gaithersburg, Maryland, 20878
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8
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Guarnotta V, Amodei R, Frasca F, Aversa A, Giordano C. Impact of Chemical Endocrine Disruptors and Hormone Modulators on the Endocrine System. Int J Mol Sci 2022; 23:ijms23105710. [PMID: 35628520 PMCID: PMC9145289 DOI: 10.3390/ijms23105710] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/14/2022] [Accepted: 05/17/2022] [Indexed: 11/16/2022] Open
Abstract
There is growing concern regarding the health and safety issues of endocrine-disrupting chemicals (EDCs). Long-term exposure to EDCs has alarming adverse health effects through both hormone-direct and hormone-indirect pathways. Non-chemical agents, including physical agents such as artificial light, radiation, temperature, and stress exposure, are currently poorly investigated, even though they can seriously affect the endocrine system, by modulation of hormonal action. Several mechanisms have been suggested to explain the interference of EDCs with hormonal activity. However, difficulty in quantifying the exposure, low standardization of studies, and the presence of confounding factors do not allow the establishment of a causal relationship between endocrine disorders and exposure to specific toxic agents. In this review, we focus on recent findings on the effects of EDCs and hormone system modulators on the endocrine system, including the thyroid, parathyroid glands, adrenal steroidogenesis, beta-cell function, and male and female reproductive function.
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Affiliation(s)
- Valentina Guarnotta
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties “G. D’Alessandro” (PROMISE), Section of Endocrinology, University of Palermo, Piazza delle Cliniche 2, 90127 Palermo, Italy; (V.G.); (R.A.)
| | - Roberta Amodei
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties “G. D’Alessandro” (PROMISE), Section of Endocrinology, University of Palermo, Piazza delle Cliniche 2, 90127 Palermo, Italy; (V.G.); (R.A.)
| | - Francesco Frasca
- Endocrinology Section, Department of Clinical and Experimental Medicine, Garibaldi Nesima Hospital, University of Catania, 95122 Catania, Italy;
| | - Antonio Aversa
- Department of Experimental and Clinical Medicine, Section of Endocrinology, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy;
| | - Carla Giordano
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties “G. D’Alessandro” (PROMISE), Section of Endocrinology, University of Palermo, Piazza delle Cliniche 2, 90127 Palermo, Italy; (V.G.); (R.A.)
- Correspondence: ; Tel.: +39-0916552110
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Rickard BP, Tan X, Fenton SE, Rizvi I. Select Per- and Polyfluoroalkyl Substances (PFAS) Induce Resistance to Carboplatin in Ovarian Cancer Cell Lines. Int J Mol Sci 2022; 23:5176. [PMID: 35563566 PMCID: PMC9104343 DOI: 10.3390/ijms23095176] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/15/2022] [Accepted: 05/03/2022] [Indexed: 02/01/2023] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants associated with adverse reproductive outcomes including reproductive cancers in women. PFAS can alter normal ovarian function, but the effects of PFAS on ovarian cancer progression and therapy response remain understudied. Ovarian cancer is the most lethal gynecologic malignancy, and a major barrier to effective treatment is resistance to platinum-based chemotherapy. Platinum resistance may arise from exposure to external stimuli such as environmental contaminants. This study evaluated PFAS and PFAS mixture exposures to two human ovarian cancer cell lines to evaluate the ability of PFAS exposure to affect survival fraction following treatment with carboplatin. This is the first study to demonstrate that, at sub-cytotoxic concentrations, select PFAS and PFAS mixtures increased survival fraction in ovarian cancer cells following carboplatin treatment, indicative of platinum resistance. A concomitant increase in mitochondrial membrane potential, measured by the JC-1 fluorescent probe, was observed in PFAS-exposed and PFAS + carboplatin-treated cells, suggesting a potential role for altered mitochondrial function that requires further investigation.
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Affiliation(s)
- Brittany P. Rickard
- Curriculum in Toxicology & Environmental Medicine, University of North Carolina School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (B.P.R.); (S.E.F.)
| | - Xianming Tan
- Department of Biostatistics, University of North Carolina School of Public Health, Chapel Hill, NC 27599, USA;
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Suzanne E. Fenton
- Curriculum in Toxicology & Environmental Medicine, University of North Carolina School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (B.P.R.); (S.E.F.)
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Imran Rizvi
- Curriculum in Toxicology & Environmental Medicine, University of North Carolina School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (B.P.R.); (S.E.F.)
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
- Center for Environmental Health and Susceptibility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; North Carolina State University, Raleigh, NC 27606, USA
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10
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Conley JM, Lambright CS, Evans N, Cardon M, Medlock-Kakaley E, Wilson VS, Gray LE. A mixture of 15 phthalates and pesticides below individual chemical no observed adverse effect levels (NOAELs) produces reproductive tract malformations in the male rat. Environ Int 2021; 156:106615. [PMID: 34000504 PMCID: PMC8380680 DOI: 10.1016/j.envint.2021.106615] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 05/10/2023]
Abstract
Humans carry residues of multiple synthetic chemicals at any given point in time. Research has demonstrated that compounds with varying molecular initiating events (MIE) that disrupt common key events can act in concert to produce cumulative adverse effects. Congenital defects of the male reproductive tract are some of the most frequently diagnosed malformations in humans and chemical exposures in utero can produce these effects in laboratory animals and humans. Here, we hypothesized that in utero exposure to a mixture of pesticides and phthalates, each of which produce male reproductive tract defects individually, would produce cumulative effects even when each chemical is present at a no observed adverse effect level (NOAEL) specific for male reproductive effects. Pregnant Sprague-Dawley rats were exposed via oral gavage to a fixed-ratio dilution mixture of 5 pesticides (vinclozolin, linuron, procymidone, prochloraz, pyrifluquinazon), 1 pesticide metabolite (dichlorodiphenyldichloroethylene (DDE)), and 9 phthalates (dipentyl, dicyclohexyl, di-2-ethylhexyl, dibutyl, benzyl butyl, diisobutyl, diisoheptyl, dihexyl, and diheptyl) during the critical window of rat fetal masculinization (gestation day 14-18). The top dose (100% dose) contained each compound at a concentration 2-fold greater than the individual chemical NOAEL followed by a dilution series that represented each chemical at NOAEL, NOAEL/2, NOAEL/4, NOAEL/8, NOAEL/15, NOAEL/100, NOAEL/1000. Reduced fetal testis gene expression occurred at NOAEL/15, reduced fetal testis testosterone production occurred at NOAEL/8, reduced anogenital distance, increased nipple retention, and delayed puberty occurred at NOAEL/4, and severe effects including genital malformations and weight reductions in numerous reproductive tissues occurred at NOAEL/2. This study demonstrates that these phthalates and pesticides acted cumulatively to produce adverse effects at doses below which any individual chemical had been shown to produce an effect alone and even though they have different MIEs.
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Affiliation(s)
- Justin M Conley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - Christy S Lambright
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - Nicola Evans
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - Mary Cardon
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - Elizabeth Medlock-Kakaley
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - Vickie S Wilson
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
| | - L Earl Gray
- U.S. Environmental Protection Agency/Office of Research & Development/Center for Public Health and Environmental Assessment/Public Health and Integrated Toxicology Division, Research Triangle Park, NC 27711, United States.
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11
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Jorgensen A, Svingen T, Miles H, Chetty T, Stukenborg JB, Mitchell RT. Environmental Impacts on Male Reproductive Development: Lessons from Experimental Models. Horm Res Paediatr 2021; 96:190-206. [PMID: 34607330 DOI: 10.1159/000519964] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/11/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Male reproductive development in mammals can be divided into a gonadal formation phase followed by a hormone-driven differentiation phase. Failure of these processes may result in Differences in Sex Development (DSD), which may include abnormalities of the male reproductive tract, including cryptorchidism, hypospadias, infertility, and testicular germ cell cancer (TGCC). These disorders are also considered to be part of a testicular dysgenesis syndrome (TDS) in males. Whilst DSDs are considered to result primarily from genetic abnormalities, the development of TDS disorders is frequently associated with environmental factors. SUMMARY In this review, we will discuss the development of the male reproductive system in relation to DSD and TDS. We will also describe the experimental systems, including studies involving animals and human tissues or cells that can be used to investigate the role of environmental factors in inducing male reproductive disorders. We will discuss recent studies investigating the impact of environmental chemicals (e.g., phthalates and bisphenols), lifestyle factors (e.g., smoking) and pharmaceuticals (e.g., analgesics) on foetal testis development. Finally, we will describe the evidence, involving experimental and epidemiologic approaches, for a role of environmental factors in the development of specific male reproductive disorders, including cryptorchidism, hypospadias, and TGCC. Key Messages: Environmental exposures can impact the development and function of the male reproductive system in humans. Epidemiology studies and experimental approaches using human tissues are important to translate findings from animal studies and account for species differences in response to environmental exposures.
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Affiliation(s)
- Anne Jorgensen
- Department of Growth and Reproduction, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Terje Svingen
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Harriet Miles
- Royal Hospital for Children and Young People, Edinburgh, United Kingdom
| | - Tarini Chetty
- Royal Hospital for Children and Young People, Edinburgh, United Kingdom
| | - Jan-Bernd Stukenborg
- NORDFERTIL Research Lab Stockholm, Childhood Cancer Research Unit, Department of Women's and Children's Health, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Rod T Mitchell
- Royal Hospital for Children and Young People, Edinburgh, United Kingdom.,MRC Centre for Reproductive Health, The Queen's Medical Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
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12
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Sprinkle RH, Payne-Sturges DC. Mixture toxicity, cumulative risk, and environmental justice in United States federal policy, 1980-2016 : Why, with much known, was little done? Environ Health 2021; 20:104. [PMID: 34535123 PMCID: PMC8449500 DOI: 10.1186/s12940-021-00764-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/24/2021] [Indexed: 05/12/2023]
Abstract
Toxic chemicals - "toxicants" - have been studied and regulated as single entities, and, carcinogens aside, almost all toxicants, single or mixed and however altered, have been thought harmless in very low doses or very weak concentrations. Yet much work in recent decades has shown that toxicants can injure wildlife, laboratory animals, and humans following exposures previously expected to be harmless. Additional work has shown that toxicants can act not only individually and cumulatively but also collectively and even synergistically and that they affect disadvantaged communities inordinately - and therefore, as argued by reformers, unjustly. As late as December 2016, the last full month before the inauguration of a president promising to rescind major environmental regulations, the United States federal environmental-health establishment, as led by the Environmental Protection Agency (EPA), had not developed coherent strategies to mitigate such risks, to alert the public to their plausibility, or to advise leadership in government and industry about their implications. To understand why, we examined archival materials, reviewed online databases, read internal industry communications, and interviewed experts. We confirmed that external constraints, statutory and judicial, had been in place prior to EPA's earliest interest in mixture toxicity, but we found no overt effort, certainly no successful effort, to loosen those constraints. We also found internal constraints: concerns that fully committing to the study of complex mixtures involving numerous toxicants would lead to methodological drift within the toxicological community and that trying to act on insights from such study could lead only to regulatory futility. Interaction of these constraints, external and internal, shielded the EPA by circumscribing its responsibilities and by impeding movement toward paradigmatic adjustment, but it also perpetuated scientifically dubious policies, such as those limiting the evaluation of commercial chemical formulations, including pesticide formulations, to only those ingredients said by their manufacturers to be active. In this context, regulators' disregard of synergism contrasted irreconcilably with biocide manufacturers' understanding that synergism enhanced lethality and patentability. In the end, an effective national response to mixture toxicity, cumulative risk, and environmental injustice did not emerge. In parallel, though, the National Institute of Environmental Health Sciences, which was less constrained, pursued with scientific investigation what the EPA had not pursued with regulatory action.
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Affiliation(s)
| | - Devon C Payne-Sturges
- Maryland Institute for Applied Environmental Health, School of Public Health, University of Maryland, College Park, MD, 20742, USA
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13
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De Falco M, Laforgia V. Combined Effects of Different Endocrine-Disrupting Chemicals (EDCs) on Prostate Gland. Int J Environ Res Public Health 2021; 18:9772. [PMID: 34574693 DOI: 10.3390/ijerph18189772] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 11/26/2022]
Abstract
Endocrine-disrupting chemicals (EDCs) belong to a heterogeneous class of environmental pollutants widely diffused in different aquatic and terrestrial habitats. This implies that humans and animals are continuously exposed to EDCs from different matrices and sources. Moreover, pollution derived from anthropic and industrial activities leads to combined exposure to substances with multiple mechanisms of action on the endocrine system and correlated cell and tissue targets. For this reason, specific organs, such as the prostate gland, which physiologically are under the control of hormones like androgens and estrogens, are particularly sensitive to EDC stimulation. It is now well known that an imbalance in hormonal regulation can cause the onset of various prostate diseases, from benign prostate hyperplasia to prostate cancer. In this review, starting with the description of normal prostate gland anatomy and embryology, we summarize recent studies reporting on how the multiple and simultaneous exposure to estrogenic and anti-androgenic compounds belonging to EDCs are responsible for an increase in prostate disease incidence in the human population.
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14
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Gray LE, Lambright CS, Conley JM, Evans N, Furr JR, Hannas BR, Wilson VS, Sampson H, Foster PMD. Genomic and Hormonal Biomarkers of Phthalate-Induced Male Rat Reproductive Developmental Toxicity Part II: A Targeted RT-qPCR Array Approach That Defines a Unique Adverse Outcome Pathway. Toxicol Sci 2021; 182:195-214. [PMID: 33983380 DOI: 10.1093/toxsci/kfab053] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Previously, we demonstrated that exposure to some diortho-phthalate esters during sexual differentiation disrupts male reproductive development by reducing fetal rat testis testosterone production (T Prod) and gene expression in a dose-related manner. The objectives of the current project were to expand the number of test compounds that might reduce fetal T Prod, including phthalates, phthalate alternatives, pesticides, and drugs, and to compare reductions in T Prod with altered testis mRNA expression. We found that PEs that disrupt T Prod also reduced expression of a unique "cluster" of mRNAs for about 35 genes related to sterol transport, testosterone and insulin-like hormone 3 hormone syntheses, and lipoprotein signaling and cholesterol synthesis. However, phthalates had little or no effect on mRNA expression of genes in peroxisome proliferator-activated receptor (PPAR) pathways in the fetal liver, whereas the 3 PPAR agonists induced the expression of mRNA for multiple fetal liver PPAR pathway genes without reducing testis T Prod. In summary, phthalates that disrupt T Prod act via a novel adverse outcome pathway including down regulation of mRNA for genes involved in fetal endocrine function and cholesterol synthesis and metabolism. This profile was not displayed by PEs that did not reduce T Prod, PPAR agonists or the other chemicals. Reductions in fetal testis gene expression and T Prod in utero can be used to establish relative potency factors that can be used quantitatively to predict the doses of individual PEs and mixtures of phthalates that produce adverse reproductive tract effects in male offspring.
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Affiliation(s)
- Leon Earl Gray
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
| | - Christy S Lambright
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
| | - Justin M Conley
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
| | - Nicola Evans
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
| | | | - Bethany R Hannas
- Corteva, Agriscience, Haskell R&D Center, Newark, Delaware 19711, USA
| | - Vickie S Wilson
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
| | - Hunter Sampson
- Reproductive and Developmental Toxicology Branch, PHITD, CPHEA, ORD, US Environmental Protection Agency, North Carolina 27711, USA
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15
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Hamid N, Junaid M, Pei DS. Combined toxicity of endocrine-disrupting chemicals: A review. Ecotoxicol Environ Saf 2021; 215:112136. [PMID: 33735605 DOI: 10.1016/j.ecoenv.2021.112136] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/23/2021] [Accepted: 03/07/2021] [Indexed: 06/12/2023]
Abstract
The combined toxicological assessment provides a realistic approach for hazard evaluation of chemical cocktails that co-existed in the environment. This review provides a holistic insight into the studies highlighting the mixture toxicity of the endocrine-disrupting chemicals (EDCs), especially focusing on the screening of biochemical pathways and other toxicogenetic endpoints. Reviewed literature showed that numerous multiplexed toxicogenomic techniques were applied to determine reproductive effects in vertebrates, but limited studies were found in non-mammalian species after mixture chemical exposure. Further, we found that the experimental design and concentration selection are the two important parameters in mixture toxicity studies that should be time- and cost-effective, highly precise, and environmentally relevant. A summary of EDC mixtures affecting the thyroid axis, estrogen axis, androgen axis, growth stress, and immune system via in vivo bioassays was also presented. It is interesting to mention that majority of estrogenic effects of the mixtures were sex-dependent, particularly observed in male fish as compared to female fish. Further, the androgen axis was perturbed with serious malformations in male rat testis (epididymal or gubernacular lesions, and deciduous spermatids). Also, transgenerational epigenetic effects were promoted in the F3 and F4 generations in the form of DNA methylation epimutations in sperm, increasing polycystic ovaries and reducing the offspring. Similarly, increased oxidative stress, high antioxidant enzymatic activities, disturbed estrous cycle, and decreased steroidogenesis were the commonly found effects after acute or chronic exposure to EDC mixtures. Importantly, the concentration addition (CA) and independent action (IA) models became more prevalent and suitable predictive models to unveil the prominence of synergistic estrogenic and anti-androgenic effects of chemical mixtures. More importantly, this review encompasses the research challenges and gaps in the existing knowledge and specific future research perspectives on combined toxicity.
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Affiliation(s)
- Naima Hamid
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Muhammad Junaid
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - De-Sheng Pei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Life Science, Henan Normal University, Xinxiang 453007, Henan, China.
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16
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Walker C, Garza S, Papadopoulos V, Culty M. Impact of endocrine-disrupting chemicals on steroidogenesis and consequences on testicular function. Mol Cell Endocrinol 2021; 527:111215. [PMID: 33657436 DOI: 10.1016/j.mce.2021.111215] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/26/2022]
Abstract
Testicular steroidogenesis is a tightly regulated process that produces the androgens important for the development, maintenance and function of the male reproductive system. These androgens are also essential for overall health, and well-being. Disruptions in the ability of the testis to form steroids can result in developmental abnormalities, dysfunction, and infertility. Endocrine-disrupting chemicals (EDCs) can interfere with the intricate signaling and metabolizing networks that produce androgens and promote their dysfunction. These chemicals are found ubiquitously in our environment, as they are integral components of products that are used every day. The effects of EDCs, such as bisphenols, phthalates, and alkyl chemicals, have been studied independently, revealing deleterious effects; but the combined influence of these structures on steroidogenesis has yet to be completely elucidated. This manuscript presents an updated review on EDC mixtures and their impact on testicular function and fertility, highlighting new findings that illustrate the anti-androgenic capabilities of EDC mixtures.
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Affiliation(s)
- Casandra Walker
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Samuel Garza
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Martine Culty
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA.
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17
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Mattiske DM, Pask AJ. Endocrine disrupting chemicals in the pathogenesis of hypospadias; developmental and toxicological perspectives. Curr Res Toxicol 2021; 2:179-91. [PMID: 34345859 DOI: 10.1016/j.crtox.2021.03.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
Penis development is regulated by a tight balance of androgens and estrogens. EDCs that impact androgen/estrogen balance during development cause hypospadias. Cross-disciplinary collaborations are needed to define a mechanistic link.
Hypospadias is a defect in penile urethral closure that occurs in approximately 1/150 live male births in developed nations, making it one of the most common congenital abnormalities worldwide. Alarmingly, the frequency of hypospadias has increased rapidly over recent decades and is continuing to rise. Recent research reviewed herein suggests that the rise in hypospadias rates can be directly linked to our increasing exposure to endocrine disrupting chemicals (EDCs), especially those that affect estrogen and androgen signalling. Understanding the mechanistic links between endocrine disruptors and hypospadias requires toxicologists and developmental biologists to define exposures and biological impacts on penis development. In this review we examine recent insights from toxicological, developmental and epidemiological studies on the hormonal control of normal penis development and describe the rationale and evidence for EDC exposures that impact these pathways to cause hypospadias. Continued collaboration across these fields is imperative to understand the full impact of endocrine disrupting chemicals on the increasing rates of hypospadias.
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Key Words
- Androgen
- BBP, benzyl butyl phthalate
- BPA, bisphenol A
- DBP, Σdibutyl phthalate
- DDT, dichlorodiphenyltrichloroethane
- DEHP, Σdi-2(ethylhexyl)-phthalate
- DHT, dihydrotestosterone
- EDC, endocrine disrupting chemicals
- EMT, epithelial to mesenchymal transition
- ER, estrogen receptor
- Endocrine disruptors
- Estrogen
- GT, genital tubercle
- Hypospadias
- NOAEL, no observed adverse effect level
- PBB, polybrominated biphenyl
- PBDE, polybrominated diphenyl ether
- PCB, polychlorinated biphenyl
- PCE, tetrachloroethylene
- Penis
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18
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Amjad S, Rahman MS, Pang WK, Ryu DY, Adegoke EO, Park YJ, Pang MG. Effects of phthalates on the functions and fertility of mouse spermatozoa. Toxicology 2021; 454:152746. [PMID: 33711355 DOI: 10.1016/j.tox.2021.152746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/09/2021] [Accepted: 03/06/2021] [Indexed: 11/16/2022]
Abstract
Phthalates are common environmental pollutants that are presumed to negatively impact male fertility including animals and humans. Particularly, these potential xenoestrogens may alter male fertility by binding to specific sperm receptors. Although several studies have characterized the toxic effects of single phthalates, epidemiological studies indicate that humans are typically exposed to phthalate mixtures. Here, we tested an environmental-related phthalate combination composed of 21 % di(2-ethylhexyl) phthalate, 15 % diisononyl phthalate, 8% diisobutyl phthalate, 15 % dibutyl phthalate, 35 % diethyl phthalate, and 5% benzylbutyl phthalate. Specifically, the effects of short-term exposure (90 min) to various concentrations (1, 10, 100, and 500 μg/mL) of this phthalate mixture on several important sperm processes, oocyte fertilization, and embryo production were assessed. All phthalate concentrations significantly decreased sperm motility and hyperactivity by compromising the sperm's ability to generate ATP. Additionally, short-term phthalate exposure (>10 μg/mL) also induced abnormal capacitation and the acrosome reaction by upregulating protein tyrosine phosphorylation via a protein kinase-A-dependent pathway. Furthermore, phthalate exposure (particularly at doses exceeding 10 μg/mL) significantly affected fertilization and early embryonic development. Together, our findings indicate that the studied phthalate mixtures adversely affected sperm motility, capacitation, and acrosome reaction, which resulted in poor fertilization rates and repressed embryonic development. Moreover, the lowest-observed-adverse-effect dose of the phthalate mixture tested can be assumed to be < 1 μg/mL in vitro.
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Affiliation(s)
- Shehreen Amjad
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Md Saidur Rahman
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Won-Ki Pang
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Do-Yeal Ryu
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Elikanah Olusayo Adegoke
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Yoo-Jin Park
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea
| | - Myung-Geol Pang
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong, Gyeonggi-do, 17546, Republic of Korea.
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19
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Rider CV, McHale CM, Webster TF, Lowe L, Goodson WH, La Merrill MA, Rice G, Zeise L, Zhang L, Smith MT. Using the Key Characteristics of Carcinogens to Develop Research on Chemical Mixtures and Cancer. Environ Health Perspect 2021; 129:35003. [PMID: 33784186 PMCID: PMC8009606 DOI: 10.1289/ehp8525] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/19/2021] [Accepted: 03/10/2021] [Indexed: 05/09/2023]
Abstract
BACKGROUND People are exposed to numerous chemicals throughout their lifetimes. Many of these chemicals display one or more of the key characteristics of carcinogens or interact with processes described in the hallmarks of cancer. Therefore, evaluating the effects of chemical mixtures on cancer development is an important pursuit. Challenges involved in designing research studies to evaluate the joint action of chemicals on cancer risk include the time taken to perform the experiments because of the long latency and choosing an appropriate experimental design. OBJECTIVES The objectives of this work are to present the case for developing a research program on mixtures of environmental chemicals and cancer risk and describe recommended approaches. METHODS A working group comprising the coauthors focused attention on the design of mixtures studies to inform cancer risk assessment as part of a larger effort to refine the key characteristics of carcinogens and explore their application. Working group members reviewed the key characteristics of carcinogens, hallmarks of cancer, and mixtures research for other disease end points. The group discussed options for developing tractable projects to evaluate the joint effects of environmental chemicals on cancer development. RESULTS AND DISCUSSION Three approaches for developing a research program to evaluate the effects of mixtures on cancer development were proposed: a chemical screening approach, a transgenic model-based approach, and a disease-centered approach. Advantages and disadvantages of each are discussed. https://doi.org/10.1289/EHP8525.
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Affiliation(s)
- Cynthia V. Rider
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Cliona M. McHale
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
| | - Thomas F. Webster
- Department of Environmental Health, School of Public Health, Boston University, Boston, Massachusetts, USA
| | - Leroy Lowe
- Getting to Know Cancer (NGO), Truro, Nova Scotia, Canada
| | - William H. Goodson
- Department of Surgery, California Pacific Medical Center Research Institute, San Francisco, California, USA
| | - Michele A. La Merrill
- Department of Environmental Toxicology, University of California Davis, Davis, California, USA
| | - Glenn Rice
- Office of Research & Development, Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA
| | - Lauren Zeise
- Office of the Director, Office of Environmental Health and Hazard Assessment, California Environmental Protection Agency, Sacramento, California, USA
| | - Luoping Zhang
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
| | - Martyn T. Smith
- Division of Environmental Health Sciences, University of California Berkeley, School of Public Health, Berkeley, California, USA
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20
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Day DB, Collett BR, Barrett ES, Bush NR, Swan SH, Nguyen RHN, Szpiro AA, Sathyanarayana S. Phthalate mixtures in pregnancy, autistic traits, and adverse childhood behavioral outcomes. Environ Int 2021; 147:106330. [PMID: 33418196 PMCID: PMC9291724 DOI: 10.1016/j.envint.2020.106330] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/28/2020] [Accepted: 12/07/2020] [Indexed: 05/22/2023]
Abstract
BACKGROUND Prenatal exposure to multiple phthalates is ubiquitous, and yet few studies have evaluated these exposures as a mixture in relation to child autistic traits and behavioral problems. OBJECTIVES To assess cumulative associations between prenatal phthalate mixtures and child behaviors, including effect modification by exposure timing and child sex. METHODS Analyses included 501 mother/child pairs from the multicenter pregnancy cohort The Infant Development and Environment Study (TIDES). Nine maternal urinary phthalate metabolites were measured in early and late pregnancy, and behavior was assessed at ages 4-5 years using composite T scores for the Behavioral Assessment System for Children (BASC-2), which measures several dimensions of child behavior, and the Social Responsiveness Scale (SRS-2), which measures social impairment consistent with autistic traits. We utilized weighted quantile sum (WQS) regressions to examine pregnancy period-specific associations between phthalate mixtures and behavioral outcomes. Full-sample 95% WQS confidence intervals are known to be anti-conservative, so we calculated a confirmatory p-value using a permutation test. Effect modification by sex was examined with stratified analyses. RESULTS A one-quintile increase in the early pregnancy phthalate mixture was associated with increased SRS-2 total score (coefficient = 1.0, confirmatory p = 0.01) and worse adaptive skills (coefficient = -1.0, confirmatory p = 0.06) in both sexes. In sex-stratified analyses, the early pregnancy phthalate mixture was associated with increased SRS-2 total score in boys (coefficient = 1.2, confirmatory p = 0.04) and girls (coefficient = 1.0, confirmatory p = 0.10) and worse BASC-2 adaptive skills score in girls (coefficient = -1.5, confirmatory p = 0.06), while the late pregnancy phthalate mixture was associated with increased BASC-2 externalizing score in boys (coefficient = 1.3, confirmatory p = 0.03). CONCLUSION Our results suggest cumulative adverse associations between prenatal phthalate mixtures and multiple facets of childhood behavior.
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Affiliation(s)
- Drew B Day
- Center for Child Health, Behavior, and Development, Seattle Children's Research Institute, 1920 Terry Ave, Seattle, WA 98101, USA.
| | - Brent R Collett
- Center for Child Health, Behavior, and Development, Seattle Children's Research Institute, 1920 Terry Ave, Seattle, WA 98101, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
| | - Emily S Barrett
- Department of Epidemiology, Environmental and Occupational Health Sciences Institute, Rutgers School of Public Health, 170 Frelinghuysen Road, Piscataway, NJ 08854, USA.
| | - Nicole R Bush
- Center for Health and Community, Department of Psychiatry and Behavioral Sciences, Weill Institute for Neurosciences, Department of Pediatrics, University of California, San Francisco, 401 Parnassus Avenue, San Francisco, CA 94143, USA.
| | - Shanna H Swan
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 17 E. 102nd Street, CAM Building, 3 West, One Gustave L. Levy Place, New York, NY 10029, USA.
| | - Ruby H N Nguyen
- Department of Epidemiology and Community Health, University of Minnesota, 420 Delaware Street Southeast, Minneapolis, MN 55455, USA.
| | - Adam A Szpiro
- Department of Biostatistics, University of Washington, 1705 Northeast Pacific Street, Seattle, WA 98195, USA.
| | - Sheela Sathyanarayana
- Center for Child Health, Behavior, and Development, Seattle Children's Research Institute, 1920 Terry Ave, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington, 1959 Northeast Pacific Street, Seattle, WA 98195, USA.
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21
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Christiansen S, Axelstad M, Scholze M, Johansson HKL, Hass U, Mandrup K, Frandsen HL, Frederiksen H, Isling LK, Boberg J. Grouping of endocrine disrupting chemicals for mixture risk assessment - Evidence from a rat study. Environ Int 2020; 142:105870. [PMID: 32593051 DOI: 10.1016/j.envint.2020.105870] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 05/25/2023]
Abstract
Exposure to mixtures of endocrine disrupting chemicals may contribute to the rising incidence of hormone-related diseases in humans. Real-life mixtures are complex, comprised of chemicals with mixed modes of action, and essential knowledge is often lacking on how to group such chemicals into cumulative assessment groups, which is an essential prerequisite to conduct a chemical mixture risk assessment. We investigated if mixtures of chemicals with diverse endocrine modes of action can cause mixture effects on hormone sensitive endpoints in developing and adult rat offspring after perinatal exposure. Wistar rats were exposed during pregnancy and lactation simultaneously to either bisphenol A and butylparaben (Emix), diethylhexyl phthalate and procymidone (Amix), or a mixture of all four substances (Totalmix). In male offspring, the anogenital distance was significantly reduced and nipple retention increased in animals exposed to Amix and Totalmix, and the mixture effects were well approximated by the dose addition model. The combination of Amix and Emix responded with more marked changes on these and other endocrine-sensitive endpoints than each binary mixture on its own. Sperm counts were reduced by all exposures. These experimental outcomes suggest that the grouping of chemicals for mixture risk assessment should be based on common health outcomes rather than only similar modes or mechanisms of action. Mechanistic-based approaches such as the concept of Adverse Outcome Pathway (AOP) can provide important guidance if both the information on shared target tissues and the information on shared mode/mechanism of action are taken into account.
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Affiliation(s)
- Sofie Christiansen
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark.
| | - Marta Axelstad
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
| | - Martin Scholze
- Institute of Environment, Health and Societies, Brunel University London, Quad North, Kingston Lane, Uxbridge UB8 3PH, UK
| | - Hanna K L Johansson
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
| | - Ulla Hass
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
| | - Karen Mandrup
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
| | - Henrik Lauritz Frandsen
- Research Group for Analytical Food Chemistry, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, DK-2800 Kgs. Lyngby, Denmark
| | - Hanne Frederiksen
- Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Louise Krag Isling
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
| | - Julie Boberg
- Division of Diet, Disease Prevention and Toxicology, National Food Institute, Technical University of Denmark, Kemitorvet Building 202, Kgs. Lyngby DK-2800, Denmark
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de la Rosa R, Schlezinger JJ, Smith MT, Webster TF. Application of generalized concentration addition to predict mixture effects of glucocorticoid receptor ligands. Toxicol In Vitro 2020; 69:104975. [PMID: 32858110 DOI: 10.1016/j.tiv.2020.104975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/04/2020] [Accepted: 08/20/2020] [Indexed: 11/20/2022]
Abstract
Environmental exposures often occur in complex mixtures and at low concentrations. Generalized concentration addition (GCA) is a method used to estimate the joint effect of receptor ligands that vary in efficacy. GCA models have been successfully applied to mixtures of aryl hydrocarbon receptor (AhR) and peroxisome proliferator-activated receptor gamma (PPARγ) ligands, each of which can be modeled as a receptor with a single binding site. Here, we evaluated whether GCA could be applied to homodimer nuclear receptors, which have two binding sites, to predict the combined effect of full glucocorticoid receptor (GR) agonists with partial agonists. We measured transcriptional activation of GR using a cell-based bioassay. Individual concentration-response curves for dexamethasone (full agonist), prednisolone (full agonist), and medroxyprogesterone 17-acetate (partial agonist) were generated and applied in three additivity models, GCA, effect summation (ES), and relative potency factor (RPF), to generate response surfaces. GCA and RPF yielded adequate predictions of the experimental data for two full agonists. However, GCA fit experimental data significantly better than ES and RPF for all other binary mixtures. This work extends the application of GCA to homodimer nuclear receptors and improves prediction accuracy of mixture effects of GR agonists.
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23
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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] [What about the content of this article? (0)] [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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Medlock Kakaley E, Cardon MC, Gray LE, Hartig PC, Wilson VS. Generalized Concentration Addition Model Predicts Glucocorticoid Activity Bioassay Responses to Environmentally Detected Receptor-Ligand Mixtures. Toxicol Sci 2020; 168:252-263. [PMID: 30535411 DOI: 10.1093/toxsci/kfy290] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Many glucocorticoid receptor (GR) agonists have been detected in waste and surface waters domestically and around the world, but the way a mixture of these environmental compounds may elicit a total glucocorticoid activity response in water samples remains unknown. Therefore, we characterized 19 GR ligands using a CV1 cell line transcriptional activation assay applicable to water quality monitoring. Cells were treated with individual GR ligands, a fixed ratio mixture of full or partial agonists, or a nonequipotent mixture with full and partial agonists. Efficacy varied (48.09%-102.5%) and potency ranged over several orders of magnitude (1.278 × 10-10 to 3.93 × 10-8 M). Concentration addition (CA) and response addition (RA) mixtures models accurately predicted equipotent mixture responses of full agonists (r2 = 0.992 and 0.987, respectively). However, CA and RA models assume mixture compounds produce full agonist-like responses, and therefore they overestimated observed maximal efficacies for mixtures containing partial agonists. The generalized concentration addition (GCA) model mathematically permits < 100% maximal responses, and fell within the 95% confidence interval bands of mixture responses containing partial agonists. The GCA, but not CA and RA, model predictions of nonequipotent mixtures containing both full and partial agonists fell within the same statistical distribution as the observed values, reinforcing the practicality of the GCA model as the best overall model for predicting GR activation. Elucidating the mechanistic basis of GR activation by mixtures of previously detected environmental GR ligands will benefit the interpretation of environmental sample contents in future water quality monitoring studies.
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Affiliation(s)
- Elizabeth Medlock Kakaley
- *U.S. Environmental Protection Agency, Toxicity Assessment Division, Research Triangle Park, North Carolina 27711
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831
- University of North Carolina at Chapel Hill, Curriculum in Toxicology, Chapel Hill, North Carolina 27599
| | - Mary C Cardon
- *U.S. Environmental Protection Agency, Toxicity Assessment Division, Research Triangle Park, North Carolina 27711
| | - L Earl Gray
- *U.S. Environmental Protection Agency, Toxicity Assessment Division, Research Triangle Park, North Carolina 27711
| | - Phillip C Hartig
- *U.S. Environmental Protection Agency, Toxicity Assessment Division, Research Triangle Park, North Carolina 27711
| | - Vickie S Wilson
- *U.S. Environmental Protection Agency, Toxicity Assessment Division, Research Triangle Park, North Carolina 27711
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25
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Kortenkamp A. Which chemicals should be grouped together for mixture risk assessments of male reproductive disorders? Mol Cell Endocrinol 2020; 499:110581. [PMID: 31525431 DOI: 10.1016/j.mce.2019.110581] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/14/2019] [Accepted: 09/12/2019] [Indexed: 10/26/2022]
Abstract
There is concern about cumulative exposures to compounds that disrupt male sexual differentiation in foetal life, leading to irreversible effects in adulthood, including declines in semen quality, testes non-descent, malformations of the penis and testis cancer. Traditional chemical-by-chemical risk assessment approaches cannot capture the likely cumulative health risks. Past efforts of focusing on combinations of phthalates, a subgroup of chemicals suspected of contributing to these risks, do not go far enough, as they ignore the contribution of other types of chemicals. With the aim of providing criteria for the inclusion of additional chemicals in mixture risks assessments for male reproductive health, this paper examines the mechanisms of action of various chemicals capable of disrupting male sexual differentiation. An Adverse Outcome Pathway (AOP) network for malformations of the male reproductive system is constructed that includes new findings about the role of disruptions of prostaglandin signalling. This network is used to identify pathways that converge at critical nodal points to produce down-stream adverse effects. From this knowledge, combinations of chemicals with different mechanisms of action are predicted that should result in cumulative effects. These predictions are then mapped against evidence from experimental mixture studies with relevant combinations. From the outcome of this analysis it is concluded that cumulative assessment groups for male reproductive health risks should not only include phthalates but also comprise androgen receptor (AR) antagonists, chemicals capable of disrupting steroid synthesis, InsL3 production, prostaglandin signalling and co-planar polychlorinated dibenzo-dioxins together with other dioxin-like compounds. This list goes far beyond what has been suggested previously. A minimum set of chemicals to be assessed together with phthalates includes pesticides such as vinclozolin, prochloraz, procymidone, linuron, the pain killers paracetamol, aspirin and ibuprofen, pharmaceuticals such as finasteride, ketoconazole, and the lipid-lowering drug simvastin, poly-chlorinated dibenzo-dioxins and other dioxin-like pollutants and phenolics such as bisphenol A and butylparaben. AOP network analyses are essential to overcome difficulties in establishing groupings of chemicals for mixture risk assessments that derive from a narrow focus on mechanisms and modes of action.
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Affiliation(s)
- Andreas Kortenkamp
- Brunel University London, Institute of Environment, Health and Societies, Kingston Lane, Uxbridge, UB8 3PH, UK.
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Belcher SM, Cline JM, Conley J, Groeters S, Jefferson WN, Law M, Mackey E, Suen AA, Williams CJ, Dixon D, Wolf JC. Endocrine Disruption and Reproductive Pathology. Toxicol Pathol 2019; 47:1049-1071. [PMID: 31833458 PMCID: PMC8008741 DOI: 10.1177/0192623319879903] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
During the past 20 years, investigations involving endocrine active substances (EAS) and reproductive toxicity have dominated the landscape of ecotoxicological research. This has occurred in concert with heightened awareness in the scientific community, general public, and governmental entities of the potential consequences of chemical perturbation in humans and wildlife. The exponential growth of experimentation in this field is fueled by our expanding knowledge into the complex nature of endocrine systems and the intricacy of their interactions with xenobiotic agents. Complicating factors include the ever-increasing number of novel receptors and alternate mechanistic pathways that have come to light, effects of chemical mixtures in the environment versus those of single EAS laboratory exposures, the challenge of differentiating endocrine disruption from direct cytotoxicity, and the potential for transgenerational effects. Although initially concerned with EAS effects chiefly in the thyroid glands and reproductive organs, it is now recognized that anthropomorphic substances may also adversely affect the nervous and immune systems via hormonal mechanisms and play substantial roles in metabolic diseases, such as type 2 diabetes and obesity.
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Affiliation(s)
| | - J. Mark Cline
- Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | | | | | - Mac Law
- North Carolina State College of Veterinary Medicine, Raleigh, NC, USA
| | - Emily Mackey
- Michigan State University, East Lansing, MI, USA
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McComb J, Mills IG, Muller M, Berntsen HF, Zimmer KE, Ropstad E, Verhaegen S, Connolly L. Human blood-based exposure levels of persistent organic pollutant (POP) mixtures antagonise androgen receptor transactivation and translocation. Environ Int 2019; 132:105083. [PMID: 31470217 DOI: 10.1016/j.envint.2019.105083] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 06/10/2023]
Abstract
INTRODUCTION Human exposure to persistent organic pollutants (POPs) has been linked to genitourinary health-related conditions such as decreased sperm quality, hypospadias, and prostate cancer (PCa). Conventional risk assessment of POPs focuses on individual compounds. However, in real life, individuals are exposed to many compounds simultaneously. This might lead to combinatorial effects whereby the global effect of the mixture is different from the effect of the single elements or subgroups. POP mixtures may act as endocrine disruptors via the androgen receptor (AR) and potentially contribute to PCa development. AIM To determine the endocrine disrupting activity of a POP mixture and sub-mixtures based upon exposure levels detected in a human Scandinavian population, on AR transactivation and translocation in vitro. MATERIALS AND METHODS The Total POP mixture combined 29 chemicals modelled on the exposure profile of a Scandinavian population and 6 sub-mixtures: brominated (Br), chlorinated (Cl), Cl + Br, perfluorinated (PFAA), PFAA + Br, PFAA + Cl, ranging from 1/10× to 500× relative to what is found in human blood. Transactivation was measured by reporter gene assay (RGA) and translocation activity was measured by high content analysis (HCA), each using stably transfected AR model cell lines. RESULTS No agonist activity in terms of transactivation and translocation was detected for any POP mixtures. In the presence of testosterone the Cl + Br mixture at 100× and 500× blood level antagonised AR transactivation, whereas the PFAA mixture at blood level increased AR transactivation (P < 0.05). In the presence of testosterone the Cl and PFAA + Br mixtures at 1/10×, 1×, and 50× blood level antagonised AR translocation (P < 0.05). CONCLUSION Taken together, some combinations of POP mixtures can interfere with AR translocation. However, in the transactivation assay, these combinations did not affect gene transactivation. Other POP combinations were identified here as modulators of AR-induced gene transactivation without affecting AR translocation. Thus, to fully evaluate the effect of environmental toxins on AR signalling, both types of assays need to be applied.
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Affiliation(s)
- J McComb
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, Northern Ireland, United Kingdom
| | - I G Mills
- Prostate Cancer UK/Movember Centre of Excellence, Centre for Cancer Research and Cell Biology, School of Medicine, Dentistry, and Biomedical Sciences, Queen's University Belfast, Belfast BT9 7AE, Northern Ireland, United Kingdom; Nuffield Department of Surgical Sciences, University of Oxford, Level 6, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, United Kingdom
| | - M Muller
- Laboratory for Organogenesis and Regeneration, GIGA-Research, University of Liège, Liège 4000, Belgium
| | - H F Berntsen
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Post-box 369 sentrum, 0102 Oslo, Norway; Department of Administration, Lab Animal Unit, National Institute of Occupational Health, P.O. Box 5330, Oslo, Norway
| | - K E Zimmer
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Post-box 369 sentrum, 0102 Oslo, Norway
| | - E Ropstad
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Post-box 369 sentrum, 0102 Oslo, Norway
| | - S Verhaegen
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Post-box 369 sentrum, 0102 Oslo, Norway
| | - L Connolly
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, Northern Ireland, United Kingdom.
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Baken KA, Lambrechts N, Remy S, Mustieles V, Rodríguez-Carrillo A, Neophytou CM, Olea N, Schoeters G. A strategy to validate a selection of human effect biomarkers using adverse outcome pathways: Proof of concept for phthalates and reproductive effects. Environ Res 2019; 175:235-256. [PMID: 31146096 DOI: 10.1016/j.envres.2019.05.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/09/2019] [Accepted: 05/10/2019] [Indexed: 05/21/2023]
Abstract
Human biomonitoring measures the concentrations of environmental chemicals or their metabolites in body fluids or tissues. Complementing exposure biomarkers with mechanistically based effect biomarkers may further elucidate causal pathways between chemical exposure and adverse health outcomes. We combined information on effect biomarkers previously implemented in human observational studies with mechanisms of action reported in experimental studies and with information from published Adverse Outcome Pathways (AOPs), focusing on adverse reproductive effects of phthalate exposure. Phthalates constitute a group of chemicals that are ubiquitous in consumer products and have been related to a wide range of adverse health effects. As a result of a comprehensive literature search, we present an overview of effect biomarkers for reproductive toxicity that are substantiated by mechanistic information. The activation of several receptors, such as PPARα, PPARγ, and GR, may initiate events leading to impaired male and female fertility as well as other adverse effects of phthalate exposure. Therefore, these receptors appear as promising targets for the development of novel effect biomarkers. The proposed strategy connects the fields of epidemiology and toxicology and may strengthen the weight of evidence in observational studies that link chemical exposures to health outcomes.
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Affiliation(s)
- Kirsten A Baken
- Unit Health, Flemish Institute for Technological Research (VITO NV), Mol, Belgium.
| | - Nathalie Lambrechts
- Unit Health, Flemish Institute for Technological Research (VITO NV), Mol, Belgium
| | - Sylvie Remy
- Unit Health, Flemish Institute for Technological Research (VITO NV), Mol, Belgium; Department of Epidemiology and Social Medicine, University of Antwerp, Antwerp, Belgium
| | - Vicente Mustieles
- Biosanitary Research Institute of Granada (ibs.GRANADA), University Hospitals of Granada, Granada, Spain; Center for Biomedical Research (CIBM), University of Granada, Granada, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Spain
| | | | - Christiana M Neophytou
- Department of Biological Sciences, School of Pure and Applied Sciences, University of Cyprus, Nicosia, Cyprus
| | - Nicolas Olea
- Biosanitary Research Institute of Granada (ibs.GRANADA), University Hospitals of Granada, Granada, Spain; Center for Biomedical Research (CIBM), University of Granada, Granada, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Spain
| | - Greet Schoeters
- Unit Health, Flemish Institute for Technological Research (VITO NV), Mol, Belgium; Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium; Department of Environmental Medicine, Institute of Public Health, University of Southern Denmark, Odense, Denmark
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29
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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 2019; 164:166-178. [PMID: 29945228 DOI: 10.1093/toxsci/kfy069] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Christy S Lambright
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Nicola Evans
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Mary Cardon
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Johnathan Furr
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711.,Southern Research, Birmingham, Alabama 35205
| | - Vickie S Wilson
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Leon Earl Gray
- National Health and Environmental Effects Research Laboratory, Toxicity Assessment Division, U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
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Bertoncello Souza M, Passoni MT, Pälmke C, Meyer KB, Venturelli AC, Araújo G, de Castilhos BS, Morais RN, Dalsenter PR, Swan SH, Koch HM, Martino-Andrade AJ. Unexpected, ubiquitous exposure of pregnant Brazilian women to diisopentyl phthalate, one of the most potent antiandrogenic phthalates. Environ Int 2018; 119:447-454. [PMID: 30031264 DOI: 10.1016/j.envint.2018.06.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/13/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Human exposure to phthalates and other non-persistent chemicals in developing countries is largely unknown. A preliminary analysis of urinary samples from pregnant Brazilian women revealed the presence of metabolites of Diisopentyl phthalate (DiPeP). OBJECTIVES Reliably quantify DiPeP metabolites in human urine and investigate the potential antiandrogenic activity of this phthalate in rats. METHODS We initiated a pilot pregnancy cohort in Curitiba, Brazil, to examine phthalate exposure in urine samples collected in early pregnancy (n = 50) or pooled samples from early, mid and late pregnancy (n = 44). Our well established phthalate method was modified to include the primary DiPeP metabolite, monoisopentyl phthalate (MiPeP), and two additional secondary oxidized metabolites, 3OH-MiPeP and 4OH-MiPeP. In a parallel approach, we orally exposed pregnant rats to DiPeP or Di-n-butyl phthalate (DnBP; reference phthalate) at 0, 125, 250, and 500 mg/kg/day from gestation day 14 to 18 and measured ex vivo fetal testis testosterone production. RESULTS We were able to detect and quantify specific DiPeP metabolites in nearly all (98%) of the early pregnancy urine samples and in all gestational pool samples with a median concentration for MiPeP of 3.65 and 3.15 μg/L, respectively, and for the two oxidized metabolites between 1.00 and 1.70 μg/L. All three urinary DiPeP metabolites were strongly correlated (r = 0.89 to 0.99). In the rat model, the effective dose (mg/kg/day) inhibiting fetal testosterone production by 50% (ED50 [95% confidence interval]) was 93.6 [62.9-139.3] for DiPeP which was significantly lower than for DnBP (220.3 [172.9-280.7]), highlighting the strong antiandrogenic potency of DiPeP within the spectrum of the phthalates. CONCLUSIONS We unveiled and confirmed the exposure of pregnant Brazilian women to DiPeP via specific urinary metabolites. This unexpected and ubiquitous DiPeP exposure indicates to unique DiPeP exposure sources in Brazil. These exposures spark considerable concern because DiPeP is one of the most potent antiandrogenic phthalates.
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Affiliation(s)
| | | | - Claudia Pälmke
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Ruhr University Bochum, Bochum, Germany
| | - Katlyn Barp Meyer
- Department of Physiology, Federal University of Paraná, Curitiba, Brazil
| | | | - Giulia Araújo
- Department of Physiology, Federal University of Paraná, Curitiba, Brazil
| | | | | | | | - Shanna Helen Swan
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Holger Martin Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), Ruhr University Bochum, Bochum, Germany
| | - Anderson Joel Martino-Andrade
- Department of Physiology, Federal University of Paraná, Curitiba, Brazil.; Department of Pharmacology, Federal University of Paraná, Curitiba, Brazil..
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Abstract
Despite concerns of the scientific community regarding the adverse effects of human exposure to exogenous man-made chemical substances or mixtures that interfere with normal hormonal balance, the so called "endocrine disruptors (EDs)", their production has been increased during the last few decades. EDs' extensive use has been implicated in the increasing incidence of male reproductive disorders including poor semen quality, testicular malignancies and congenital developmental defects such as hypospadias and cryptorchidism. Several animal studies have demonstrated that exposure to EDs during fetal, neonatal and adult life has deleterious consequences on male reproductive system; however, the evidence on humans remains ambiguous. The complexity of their mode of action, the differential effect according to the developmental stage that exposure occurs, the latency from exposure and the influence of the genetic background in the manifestation of their toxic effects are all responsible factors for the contradictory outcomes. Furthermore, the heterogeneity in the published human studies has hampered agreement in the field. Interventional studies to establish causality would be desirable, but unfortunately the nature of the field excludes this possibility. Therefore, future studies based on standardized guidelines are necessary, in order to estimate human health risks and implement policies to limit public exposure.
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Affiliation(s)
- Stefania Lymperi
- Unit of Reproductive Endocrinology, First Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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Hejmej A, Bilinska B. The effects of flutamide on cell-cell junctions in the testis, epididymis, and prostate. Reprod Toxicol 2018; 81:1-16. [PMID: 29958919 DOI: 10.1016/j.reprotox.2018.06.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/15/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022]
Abstract
In this review, we summarize recent findings on the effect of the anti-androgen flutamide on cell-cell junctions in the male reproductive system. We outline developmental aspects of flutamide action on the testis, epididymis, and prostate, and describe changes in junction protein expression and organization of junctional complexes in the adult boar following prenatal and postnatal exposure. We also discuss findings on the mechanisms by which flutamide induces alterations in cell-cell junctions in reproductive tissues of adult males, with special emphasis on cytoplasmic effects. Based on the results from in vivo and in vitro studies in the rat, we propose that flutamide affects the expression of junction proteins and junction complex structure not only by inhibiting androgen receptor activity, but equally important by modulating protein kinase-dependent signaling in testicular cells. Additionally, results from studies on prostate cancer cell lines point to a role for the cellular molecular outfit in response to flutamide.
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Affiliation(s)
- Anna Hejmej
- Department of Endocrinology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Barbara Bilinska
- Department of Endocrinology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.
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Abstract
Phthalates are used in building materials, medical devices, and personal care products. Most studies on phthalates have focused on single phthalates, but it is important to study mixtures of phthalates because humans are exposed to such mixtures daily. We tested the hypothesis that phthalate mixture exposure decreases antral follicle growth, compromises steroidogenic capacity, and induces atresia. Antral follicles from adult CD-1 mice were cultured with vehicle control or phthalate mixture (1-500 µg/ml) for 96 h. The mixture was made of 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. During culture, antral follicle diameters were measured every 24 h to monitor growth. After culture, media were subjected to measurements of sex steroid hormones and follicles were subjected to evaluation of gene expression and atresia. The phthalate mixture (100 and 500 µg/ml) decreased antral follicle growth starting at 24 h compared to controls. The mixture at 10, 100, and 500 µg/ml also decreased androstenedione, testosterone, estrone, and estradiol levels compared to control. The mixture (10, 100, and 500 µg/ml) reduced atresia rating, but it induced more oocyte fragmentation compared to control. The phthalate mixture at different doses adversely affected cell cycle regulators, antioxidant enzymes, apoptotic factors, steroidogenic enzymes, and receptors. Collectively, these data indicate that exposure to an environmentally relevant phthalate mixture reduces antral follicle growth, induces oocyte fragmentation, and decreases hormone production by adversely affecting the expression of cell cycle regulators, apoptotic factors, steroidogenic enzymes, and receptors.
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Affiliation(s)
- Changqing Zhou
- Department of Comparative Biosciences, University of Illinois, Urbana, Illinois 61802
| | - Jodi A Flaws
- Department of Comparative Biosciences, University of Illinois, Urbana, Illinois 61802
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Pop A, Drugan T, Gutleb AC, Lupu D, Cherfan J, Loghin F, Kiss B. Estrogenic and anti-estrogenic activity of butylparaben, butylated hydroxyanisole, butylated hydroxytoluene and propyl gallate and their binary mixtures on two estrogen responsive cell lines (T47D-Kbluc, MCF-7). J Appl Toxicol 2018; 38:944-957. [DOI: 10.1002/jat.3601] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 12/31/2017] [Accepted: 01/10/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Anca Pop
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
| | - Tudor Drugan
- Department of Medical Informatics and Biostatistics; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Medicine; Cluj-Napoca Romania
| | - Arno C. Gutleb
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
- Department of Environmental Research and Innovation (ERIN); Luxembourg Institute of Science and Technology (LIST); Esch-sur-Alzette Grand Duchy of Luxembourg
| | - Diana Lupu
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
| | - Julien Cherfan
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
- UMR DIATHEC, EA 7294, Centre Européen D'Etude du Diabète; Université de Strasbourg; Boulevard René Leriche 67200 Strasbourg France
| | - Felicia Loghin
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
| | - Béla Kiss
- Department of Toxicology; “Iuliu Hatieganu” University of Medicine and Pharmacy, Faculty of Pharmacy; Cluj-Napoca Romania
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Samardzija Nenadov D, Pogrmic-Majkic K, Fa S, Stanic B, Tubic A, Andric N. Environmental mixture with estrogenic activity increases Hsd3b1 expression through estrogen receptors in immature rat granulosa cells. J Appl Toxicol 2018; 38:879-887. [DOI: 10.1002/jat.3596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/27/2017] [Accepted: 12/27/2017] [Indexed: 01/31/2023]
Affiliation(s)
| | | | - Svetlana Fa
- Department of Biology and Ecology; Faculty of Sciences, University of Novi Sad; Serbia
| | - Bojana Stanic
- Department of Environmental Engineering and Occupational Safety and Health, Faculty of Technical Sciences; University of Novi Sad; Serbia
| | - Aleksandra Tubic
- Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences; University of Novi Sad; Serbia
| | - Nebojsa Andric
- Department of Biology and Ecology; Faculty of Sciences, University of Novi Sad; Serbia
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Skakkebaek NE. A Brief Review of the Link between Environment and Male Reproductive Health: Lessons from Studies of Testicular Germ Cell Cancer. Horm Res Paediatr 2018; 86:240-246. [PMID: 26871895 DOI: 10.1159/000443400] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/16/2015] [Indexed: 11/19/2022] Open
Abstract
During the past few decades there has been a significantly increasing trend in germ cell tumours all over the world, particularly in countries with Caucasian populations. The changes in incidence have occurred so fast that only environmental factors can explain this development. This review focuses on the hypothesis that testicular germ cell cancer, which originates from germ cell neoplasia in situ, is of foetal origin and associated with other male reproductive problems through a testicular dysgenesis syndrome, also including foetal origin of impaired spermatogenesis, hypospadias and cryptorchidism. There is little doubt that environmental factors associated with modern lifestyles have - in a broad sense - had an adverse influence on male reproductive health. The hypothesis that exposure to endocrine-disrupting chemicals plays a fundamental role in this trend is plausible. This is based on evidence from animal studies that demonstrate adverse reproductive effects caused by a number of endocrine-disrupting chemicals to which humans are exposed as part of our modern lifestyle.
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Affiliation(s)
- Niels E Skakkebaek
- University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark
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Zare A, Henry D, Chua G, Gordon P, Habibi HR. Differential Hepatic Gene Expression Profile of Male Fathead Minnows Exposed to Daily Varying Dose of Environmental Contaminants Individually and in Mixture. Front Endocrinol (Lausanne) 2018; 9:749. [PMID: 30619083 PMCID: PMC6295643 DOI: 10.3389/fendo.2018.00749] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/26/2018] [Indexed: 01/09/2023] Open
Abstract
Environmental contaminants are known to impair reproduction, metabolism and development in wild life and humans. To investigate the mechanisms underlying adverse effects of contaminants, fathead minnows were exposed to a number of endocrine disruptive chemicals (EDCs) including Nonylphenol (NP), bisphenol-A (BPA), Di(2-ethylhexyl) phthalate (DEHP), and a mixture of the three chemicals for 21 days, followed by determination of the liver transcriptome by expression microarrays. Pathway analysis revealed a distinct mode of action for the individual chemicals and their mixture. The results showed expression changes in over 980 genes in response to exposure to these EDC contaminants individually and in mixture. Ingenuity Pathway core and toxicity analysis were used to identify the biological processes, pathways and the top regulators affected by these compounds. A number of canonical pathways were significantly altered, including cell cycle & proliferation, lipid metabolism, inflammatory, innate immune response, stress response, and drug metabolism. We identified 18 genes that were expressed in all individual and mixed treatments. Relevant candidate genes identified from expression microarray data were verified using quantitative PCR. We were also able to identify specific genes affected by NP, BPA, and DEHP individually, but were also affected by exposure to the mixture of the contaminants. Overall the results of this study provide novel information on the adverse health impact of contaminants tested based on pathway analysis of transcriptome data. Furthermore, the results identify a number of new biomarkers that can potentially be used for screening environmental contaminants.
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Affiliation(s)
- Ava Zare
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Darren Henry
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Gordon Chua
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Paul Gordon
- Cumming School of Medicine, Health Sciences Centre, University of Calgary, Calgary, AB, Canada
| | - Hamid R. Habibi
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Cumming School of Medicine, Health Sciences Centre, University of Calgary, Calgary, AB, Canada
- *Correspondence: Hamid R. Habibi
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Buñay J, Larriba E, Patiño-Garcia D, Cruz-Fernandes L, Castañeda-Zegarra S, Rodriguez-Fernandez M, del Mazo J, Moreno RD. Editor’s Highlight: Differential Effects of Exposure to Single Versus a Mixture of Endocrine-Disrupting Chemicals on Steroidogenesis Pathway in Mouse Testes. Toxicol Sci 2017; 161:76-86. [DOI: 10.1093/toxsci/kfx200] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Affiliation(s)
- Julio Buñay
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
| | - Eduardo Larriba
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CIB-CSIC), 28040 Madrid, Spain
| | - Daniel Patiño-Garcia
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
| | - Leonor Cruz-Fernandes
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
| | - Sergio Castañeda-Zegarra
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
| | - María Rodriguez-Fernandez
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
| | - Jesús del Mazo
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CIB-CSIC), 28040 Madrid, Spain
| | - Ricardo D Moreno
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile (PUC), Santiago 8331150, Chile
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Chang JW, Lee CC, Pan WH, Chou WC, Huang HB, Chiang HC, Huang PC. Estimated Daily Intake and Cumulative Risk Assessment of Phthalates in the General Taiwanese after the 2011 DEHP Food Scandal. Sci Rep 2017; 7:45009. [PMID: 28327585 PMCID: PMC5361203 DOI: 10.1038/srep45009] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 02/20/2017] [Indexed: 01/06/2023] Open
Abstract
A food scandal occurred in Taiwan in 2011 because the DEHP (di-2-ethylhexyl phthalate) had been intentionally used in food products. We assessed the daily intakes (DIs) and cumulative risk of phthalates in Taiwan’s general population after the scandal. The DIs of 6 phthalates, including di-n-butyl phthalate (DnBP), di-iso-butyl phthalate (DiBP), and DEHP, were evaluated using urinary phthalate metabolites. Hazard quotients of phthalates classified as affecting the reproductive (HQrep) and hepatic (HQhep) systems were assessed using cumulative approach. The creatinine-based model showed that the highest DI values in children 7-to 12- years-old were for DEHP (males: median: 4.79 μg/kg bw/d; females: median: 2.62 μg/kg bw/d). The 95th percentile (P95) of HQrep values were all >1 in the 7- to 12-year-old and 18- to 40-year-old male groups. The P95 of HQhep values were all >1 in the 7- to 18- year-old male groups. Most of the HQrep was attributable to the HQs of DnBP and DiBP (53.9–84.7%), and DEHP contributed most to HQhep (83.1–98.6%), which reveals that DnBP, DiBP and DEHP were the main risk of phthalate exposure for Taiwanese. Taiwan’s general population is widely exposed to DnBP, DiBP and DEHP, especially for young children.
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Affiliation(s)
- Jung-Wei Chang
- Research Center for Environmental Trace Toxic Substances, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Chang Lee
- Research Center for Environmental Trace Toxic Substances, National Cheng Kung University, Tainan, Taiwan.,Department of Environmental and Occupational Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Harn Pan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Division of Preventive Medicine and Health Service Research, Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Wei-Chun Chou
- National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Han-Bin Huang
- School of Public Health, National Defense Medical Center, Taipei, Taiwan
| | - Hung-Che Chiang
- National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Po-Chin Huang
- National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan.,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Safety, Health and Environmental Engineering, National United University, Miaoli, Taiwan
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Sinclair AW, Cao M, Pask A, Baskin L, Cunha GR. Flutamide-induced hypospadias in rats: A critical assessment. Differentiation 2017; 94:37-57. [DOI: 10.1016/j.diff.2016.12.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/23/2016] [Accepted: 12/02/2016] [Indexed: 01/03/2023]
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Kim YA, Kho Y, Chun KC, Koh JW, Park JW, Bunderson-Schelvan M, Cho YH. Increased Urinary Phthalate Levels in Women with Uterine Leiomyoma: A Case-Control Study. Int J Environ Res Public Health 2016; 13:E1247. [PMID: 27983712 DOI: 10.3390/ijerph13121247] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/09/2016] [Accepted: 12/11/2016] [Indexed: 01/05/2023]
Abstract
We assessed the urinary concentration of 16 phthalate metabolites in 57 women with and without uterine leiomyoma (n = 30 and 27; respectively) to determine the association between phthalate exposure and uterine leiomyoma. To evaluate exposure to di-(2-ethylhexyl) phthalate (DEHP); we calculated the molar sum of DEHP metabolites; ∑3-DEHP (combining mono-(2-ethylhexyl) phthalate (MEHP); mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP); and mono-(2-ethyl-5-oxohexyl) phthalate); ∑4-DEHP (∑3-DEHP plus mono-(2-ethyl-5-carboxypentyl) phthalate); and ∑5-DEHP (∑4-DEHP plus mono (2-(carboxylmethyl)hexyl) phthalate (2cx-MMHP)). The log transformed urinary levels of MEHP; MEHHP; 2cx-MMHP; ∑3-DEHP; ∑4-DEHP; and ∑5-DEHP in the leiomyoma group were significantly higher than those of controls. When we adjusted for age; waist circumference; and parity using multiple logistic regression analyses; we found log ∑3-DEHP (OR = 10.82; 95% CI = 1.25; 93.46) and ∑4-DEHP (OR = 8.78; 95% CI = 1.03; 75.29) were significantly associated with uterine leiomyoma. Our findings suggest an association between phthalate exposure and uterine leiomyoma. However; larger studies are needed to investigate potential interactions between phthalate exposure and uterine leiomyoma.
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Amato CM, McCoy KA. A validated protocol to quantify severity of male urogenital feminization using the MOUSE (Mouse objective urethral severity evaluation). Pediatr Res 2016; 80:880-885. [PMID: 27490742 DOI: 10.1038/pr.2016.157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/09/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND Congenital abnormalities vary in presentation, yet studies using model organisms tend to focus on occurrence rather than severity of the defect. Scoring severity of abnormalities in model systems allows explicit hypothesis testing during basic, translational, and reverse translational studies. We developed and validated a protocol to quantify severity of male urogenital feminization (hypospadias) in the mouse model. Hypospadias is one of the most common birth defects in the world. METHODS To induce genital feminization, pregnant mice were exposed to different concentrations of the antiandrogen vinclozolin. Genitalia were photographed at gestational age 18.5. A dichotomous scoring system to evaluate genital feminization was developed, and validated against histological measurements of urethral length. A training protocol was developed for novice scorers, and criteria were defined to evaluate precision and accuracy of scores. RESULTS Vinclozolin induced variation in hypospadias severity. Severity scores were tightly correlated with histologically determined urethral length and both techniques showed similar dose-response relationships. Novice observers were trained to precisely and accurately score hypospadias severity. CONCLUSION This standardized scoring system advances the mouse as a model to study urogenital development, and will facilitate research on the mechanisms driving genital feminization in males, and aid translational hypospadias research.
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Affiliation(s)
- Ciro M Amato
- Department of Biology, East Carolina University, Greenville, North Carolina
| | - Krista A McCoy
- Department of Biology, East Carolina University, Greenville, North Carolina
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Howdeshell KL, Hotchkiss AK, Gray LE. Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment. Int J Hyg Environ Health 2016; 220:179-188. [PMID: 27923611 DOI: 10.1016/j.ijheh.2016.11.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/21/2016] [Accepted: 11/14/2016] [Indexed: 11/28/2022]
Abstract
Toxicological studies of defined chemical mixtures assist human health risk assessment by establishing how chemicals interact with one another to induce an effect. This paper reviews how antiandrogenic chemical mixtures can alter reproductive tract development in rats with a focus on the reproductive toxicant phthalates. The reviewed studies compare observed mixture data to mathematical mixture model predictions based on dose addition or response addition to determine how the individual chemicals in a mixture interact (e.g., additive, greater, or less than additive). Phthalate mixtures were observed to act in a dose additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose additive effects have been reported for mixtures of phthalates with antiandrogenic pesticides of differing mechanisms of action. Overall, data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard indices, and recent cumulative risk assessments in humans indicate an excess risk to antiandrogenic chemical mixtures that include phthalates only or phthalates in combination with other antiandrogenic chemicals.
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Affiliation(s)
- Kembra L Howdeshell
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), PO Box 12233, Mail Drop K2-04, Research Triangle Park, NC 27709-2233, USA.
| | - Andrew K Hotchkiss
- National Center for Environmental Assessment (NCEA), National Health and Environmental Effects Research Laboratories (NHEERL), Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - L Earl Gray
- Toxicology Assessment Division, National Health and Environmental Effects Research Laboratories (NHEERL), Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Varshavsky JR, Zota AR, Woodruff TJ. A Novel Method for Calculating Potency-Weighted Cumulative Phthalates Exposure with Implications for Identifying Racial/Ethnic Disparities among U.S. Reproductive-Aged Women in NHANES 2001-2012. Environ Sci Technol 2016; 50:10616-10624. [PMID: 27579903 PMCID: PMC5748889 DOI: 10.1021/acs.est.6b00522] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Phthalates are ubiquitous chemicals linked to hormonal disruptions that affect reproduction and development. Multiple antiandrogenic phthalates exposure during fetal development can have greater impacts than individual exposure; thus, the National Academy of Sciences (NAS) recommends them for cumulative assessment. Using National Health and Nutrition Examination Survey data (NHANES, 2001-2012), we developed a potency-weighted sum of daily intake (∑androgen-disruptor; μg/kg/day) of di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), butyl benzyl phthalate (BBzP), and di(2-ethylhexyl) phthalate (DEHP) based on NAS recommendations, and included diethyl phthalate (DEP) and diisononyl phthalate (DiNP) in additional metrics (2005-2012). We compared racial/ethnic differences in ∑androgen-disruptor among 2842 reproductive-aged women. In sensitivity analyses, we assessed the influence of potency assumptions, alternate urine dilution adjustment methods, and weighting phthalate metabolites directly rather than daily intake estimates of parent compounds. We found that DEHP contributed most to ∑androgen-disruptor (48-64%), and that ∑androgen-disruptor decreased over time. Black women generally had higher cumulative exposures than white women, although the magnitude and precision of the difference varied by model specification. Our approach provides a blueprint for combining chemical exposures linked to common adverse outcomes, and should be considered in future exposure, risk, and epidemiological studies.
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Affiliation(s)
- Julia R. Varshavsky
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ami R. Zota
- Department of Environmental and Occupational Health, Milken Institute School of Public Health, George Washington University, Washington, D.C. 20052, United States
| | - Tracey J. Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology, and Reproductive Sciences, Institute for Health Policy Studies, University of California, San Francisco, San Francisco, California 94143, United States
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Fiandanese N, Borromeo V, Berrini A, Fischer B, Schaedlich K, Schmidt JS, Secchi C, Pocar P. Maternal exposure to a mixture of di(2-ethylhexyl) phthalate (DEHP) and polychlorinated biphenyls (PCBs) causes reproductive dysfunction in adult male mouse offspring. Reprod Toxicol 2016; 65:123-132. [DOI: 10.1016/j.reprotox.2016.07.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 06/28/2016] [Accepted: 07/08/2016] [Indexed: 10/21/2022]
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Pop A, Drugan T, Gutleb AC, Lupu D, Cherfan J, Loghin F, Kiss B. Individual and combined in vitro (anti)androgenic effects of certain food additives and cosmetic preservatives. Toxicol In Vitro 2016; 32:269-77. [DOI: 10.1016/j.tiv.2016.01.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/13/2016] [Accepted: 01/22/2016] [Indexed: 12/17/2022]
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Chojnacka K, Hejmej A, Zarzycka M, Tworzydlo W, Bilinski S, Pardyak L, Kaminska A, Bilinska B. Flutamide induces alterations in the cell-cell junction ultrastructure and reduces the expression of Cx43 at the blood-testis barrier with no disturbance in the rat seminiferous tubule morphology. Reprod Biol Endocrinol 2016; 14:14. [PMID: 27036707 PMCID: PMC4818424 DOI: 10.1186/s12958-016-0144-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/17/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Present study was designed to establish a causal connection between changes in the cell-cell junction protein expression at the blood-testis barrier and alterations in the adult rat testis histology following an anti-androgen flutamide exposure. Particular emphasis was placed on the basal ectoplasmic specialization (ES) in the seminiferous epithelium and expression of gap junction protein, connexin 43 (Cx43). METHODS Flutamide (50 mg/kg body weight) was administered to male rats daily from 82 to 88 postnatal day. Testes from 90-day-old control and flutamide-exposed rats were used for all analyses. Testis morphology was analyzed using light and electron microscopy. Gene and protein expressions were analyzed by real-time RT-PCR and Western blotting, respectively, protein distribution by immunohistochemistry, and steroid hormone concentrations by radioimmunoassay. RESULTS Seminiferous epithelium of both groups of rats displayed normal histology without any loss of germ cells. In accord, no difference in the apoptosis and proliferation level was found between control and treated groups. As shown by examination of semi-thin and ultrathin sections, cell surface occupied by the basal ES connecting neighboring Sertoli cells and the number of gap and tight junctions coexisting with the basal ES were apparently reduced in flutamide-treated rats. Moreover, the appearance of unconventional circular ES suggests enhanced internalization and degradation of the basal ES. These changes were accompanied by decreased Cx43 and ZO-1 expression (p < 0.01) and a loss of linear distribution of these proteins at the region of the blood-testis barrier. On the other hand, Cx43 expression in the interstitial tissue of flutamide-treated rats increased (p < 0.01), which could be associated with Leydig cell hypertrophy. Concomitantly, both intratesticular testosterone and estradiol concentrations were elevated (p < 0.01), but testosterone to estradiol ratio decreased significantly (p < 0.05) in flutamide-treated rats compared to the controls. CONCLUSIONS Short-term treatment with flutamide applied to adult rats exerts its primary effect on the basal ES, coexisting junctional complexes and their constituent proteins Cx43 and ZO-1, without any apparent morphological alterations in the seminiferous epithelium. In the interstitial compartment, however, short-term exposure leads to both histological and functional changes of the Leydig cells.
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Affiliation(s)
- Katarzyna Chojnacka
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Anna Hejmej
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Marta Zarzycka
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Waclaw Tworzydlo
- Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Szczepan Bilinski
- Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Laura Pardyak
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Alicja Kaminska
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Barbara Bilinska
- Department of Endocrinology, Institute of Zoology, Jagiellonian University, Krakow, Poland
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Fournier K, Tebby C, Zeman F, Glorennec P, Zmirou-Navier D, Bonvallot N. Multiple exposures to indoor contaminants: Derivation of benchmark doses and relative potency factors based on male reprotoxic effects. Regul Toxicol Pharmacol 2016; 74:23-30. [DOI: 10.1016/j.yrtph.2015.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/23/2015] [Accepted: 11/24/2015] [Indexed: 12/19/2022]
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Abstract
Introduction Endocrine disruptors or environmental agents, disrupt the endocrine system, leading to various adverse effects in humans and animals. Although the phenomenon has been noted historically in the cases of diethylstilbestrol (DES) and dichlorodiphenyltrichloroethane (DDT), the term “endocrine disruptor” is relatively new. Endocrine disruptors can have a variety of hormonal activities such as estrogenicity or anti-androgenicity. The focus of this review concerns on the induction of hypospadias by exogenous estrogenic endocrine disruptors. This has been a particular clinical concern secondary to reported increased incidence of hypospadias. Herein, the recent literature is reviewed as to whether endocrine disruptors cause hypospadias. Methods A literature search was performed for studies involving both humans and animals. Studies within the past 5 years were reviewed and categorized into basic science, clinical science, epidemiologic, or review studies. Results Forty-three scientific articles were identified. Relevant sentinel articles were also reviewed. Additional pertinent studies were extracted from the reference of the articles that obtained from initial search results. Each article was reviewed and results presented. Overall, there were no studies which definitely stated that endocrine disruptors caused hypospadias. However, there were multiple studies which implicated endocrine disruptors as one component of a multifactorial model for hypospadias. Conclusions Endocrine disruption may be one of the many critical steps in aberrant development that manifests as hypospadias.
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Affiliation(s)
- Sisir Botta
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Gerald R Cunha
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Laurence S Baskin
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, USA
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