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Peralta M, Lizcano F. Endocrine Disruptors and Metabolic Changes: Impact on Puberty Control. Endocr Pract 2024; 30:384-397. [PMID: 38185329 DOI: 10.1016/j.eprac.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 01/09/2024]
Abstract
OBJECTIVE This study aims to explore the significant impact of environmental chemicals on disease development, focusing on their role in developing metabolic and endocrine diseases. The objective is to understand how these chemicals contribute to the increasing prevalence of precocious puberty, considering various factors, including epigenetic changes, lifestyle, and emotional disturbances. METHODS The study employs a comprehensive review of descriptive observational studies in both human and animal models to identify a degree of causality between exposure to environmental chemicals and disease development, specifically focusing on endocrine disruption. Due to ethical constraints, direct causation studies in human subjects are not feasible; therefore, the research relies on accumulated observational data. RESULTS Puberty is a crucial life period with marked physiological and psychological changes. The age at which sexual characteristics develop is changing in many regions. The findings indicate a correlation between exposure to endocrine-disrupting chemicals and the early onset of puberty. These chemicals have been shown to interfere with normal hormonal processes, particularly during critical developmental stages such as adolescence. The research also highlights the interaction of these chemical exposures with other factors, including nutritional history, social and lifestyle changes, and emotional stress, which together contribute to the prevalence of precocious puberty. CONCLUSION Environmental chemicals significantly contribute to the development of certain metabolic and endocrine diseases, particularly in the rising incidence of precocious puberty. Although the evidence is mainly observational, it adequately justifies regulatory actions to reduce exposure risks. Furthermore, these findings highlight the urgent need for more research on the epigenetic effects of these chemicals and their wider impact on human health, especially during vital developmental periods.
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Affiliation(s)
- Marcela Peralta
- Center of Biomedical Investigation Universidad de La Sabana, CIBUS, Chía, Colombia
| | - Fernando Lizcano
- Center of Biomedical Investigation Universidad de La Sabana, CIBUS, Chía, Colombia; Department of Endocrinology, Diabetes and Nutrition, Fundación CardioInfantil-Instituto de Cardiología, Bogotá, Colombia.
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Developmental Exposure to DDT Disrupts Transcriptional Regulation of Postnatal Growth and Cell Renewal of Adrenal Medulla. Int J Mol Sci 2023; 24:ijms24032774. [PMID: 36769098 PMCID: PMC9917778 DOI: 10.3390/ijms24032774] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Dichlorodiphenyltrichloroethane (DDT) is the most widespread persistent pollutant with endocrine-disrupting properties. DDT has been shown to disrupt secretory and morphogenetic processes in the adrenal cortex. The present investigation aimed to evaluate transcriptional regulation of postnatal growth of the adrenal medulla and formation of the pools necessary for self-renewal of medullary cells in rats that developed under low-dose exposure to DDT. The study was performed using male Wistar rats exposed to low doses of o,p'-DDT during prenatal and postnatal development. Light microscopy and histomorphometry revealed diminished medulla growth in the DDT-exposed rats. Evaluation of Ki-67 expression in chromaffin cells found later activation of proliferation indicative of retarded growth of the adrenal medulla. All DDT-exposed rats exhibited a gradual decrease in tyrosine hydroxylase production by adrenal chromaffin cells. Immunohistochemical evaluation of nuclear β-catenin, transcription factor Oct4, and ligand of sonic hedgehog revealed increased expression of all factors after termination of growth in the control rats. The DDT-exposed rats demonstrated diminished increases in Oct4 and sonic hedgehog expression and lower levels of canonical Wnt signaling activation. Thus, developmental exposure to the endocrine disruptor o,p'-DDT alters the transcriptional regulation of morphogenetic processes in the adrenal medulla and evokes a slowdown in its growth and in the formation of a reserve pool of cells capable of dedifferentiation and proliferation that maintain cellular homeostasis in adult adrenals.
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Pinson A, Sevrin E, Chatzi C, Le Gac B, Thiry M, Westbrook GL, Parent AS. Induction of Oxidative Stress and Alteration of Synaptic Gene Expression in Newborn Hippocampal Granule Cells after Developmental Exposure to Aroclor 1254. Neuroendocrinology 2022; 113:1248-1261. [PMID: 36257292 PMCID: PMC10110769 DOI: 10.1159/000527576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/10/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Hippocampal newborn neurons integrate into functional circuits where they play an important role in learning and memory. We previously showed that perinatal exposure to Aroclor 1254, a commercial mixture of polychlorinated biphenyls (PCBs) associated with alterations of cognitive function in children, disrupted the normal maturation of excitatory synapses in the dentate gyrus. We hypothesized that hippocampal immature neurons underlie some of the cognitive effects of PCBs. METHODS We used newly generated neurons to examine the effects of PCBs in mice following maternal exposure. Newborn dentate granule cells were tagged with enhanced green fluorescent protein using a transgenic mouse line. The transcriptome of the newly generated granule cells was assessed using RNA sequencing. RESULTS Gestational and lactational exposure to 6 mg/kg/day of Aroclor 1254 disrupted the mRNA expression of 1,308 genes in newborn granule cells. Genes involved in mitochondrial functions were highly enriched with 154 genes significantly increased in exposed compared to control mice. The upregulation of genes involved in oxidative phosphorylation was accompanied by signs of endoplasmic reticulum stress and an increase in lipid peroxidation, a marker of oxidative stress, in the subgranular zone of the dentate gyrus but not in mature granule cells in the granular zone. Aroclor 1254 exposure also disrupted the expression of synaptic genes. Using laser-captured subgranular and granular zones, this effect was restricted to the subgranular zone, where newborn neurons are located. CONCLUSION Our data suggest that gene expression in newborn granule cells is disrupted by Aroclor 1254 and provide clues to the effects of endocrine-disrupting chemicals on the brain.
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Affiliation(s)
- Anneline Pinson
- Neuroendocrinology Unit, GIGA-Neurosciences, University of Liège, Liège, Belgium
| | - Elena Sevrin
- Neuroendocrinology Unit, GIGA-Neurosciences, University of Liège, Liège, Belgium
| | - Christina Chatzi
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Benjamin Le Gac
- Neuroendocrinology Unit, GIGA-Neurosciences, University of Liège, Liège, Belgium
| | - Marc Thiry
- Cellular and tissular biology, GIGA-Neurosciences, University of Liège, Liège, Belgium
| | - Gary L Westbrook
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Anne-Simone Parent
- Neuroendocrinology Unit, GIGA-Neurosciences, University of Liège, Liège, Belgium
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Zoeller RT. Endocrine disrupting chemicals and thyroid hormone action. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2021; 92:401-417. [PMID: 34452692 DOI: 10.1016/bs.apha.2021.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Thyroid hormones (predominantly thyroxine, T4, and triiodothyronine, T3) are essential for normal development and for adult physiology. There are several challenges, however, that make identifying chemicals that produce adverse effects by interfering with the thyroid system difficult. First, individual variability in serum concentrations of thyroid hormones represent only about 10% of the population reference range that is considered to be "normal." This means that populations studies evaluating the relationship between chemical exposure and serum thyroid hormones must be large enough to overcome this internal variance. In addition, we know that there are chemicals that do not produce changes in thyroid hormone levels, but nevertheless impact thyroid signaling in target tissues. A good example is that of polychlorinated biphenyls (PCBs). PCB exposure during development are clearly associated with cognitive deficits in humans. But PCB exposure isn't uniformly associated with a reduction in serum thyroid hormone in human populations despite mechanistic studies showing that PCBs reduce serum T4 in animals. In contrast, perchlorate is a chemical that inhibits iodide uptake, thereby reducing thyroid hormone synthesis and serum hormone levels. Human studies have been variable in identifying a relationship between thyroid hormone and perchlorate exposure, but studies also show that dietary iodine, cigarette smoking and other factors can modify this relationship. The conclusion is that identifying chemicals that interfere with thyroid hormone could depend on in vitro analysis of chemicals that interact with different proteins important for thyroid hormone to function properly.
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Affiliation(s)
- R Thomas Zoeller
- Biology Department, University of Massachusetts Amherst, Amherst, MA, United States; School of Science and Technology, Örebro University, Örebro, Sweden.
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Shallie PD, Sulaiman AI, Oladejo MK, Shallie OF, Naicker T. Early glutathione intervention educed positive correlation between VGLUT1 expression and spatial memory in the Nω-nitro-L-arginine methyl rat model of IUGR. IBRO Neurosci Rep 2021; 10:136-141. [PMID: 34179867 PMCID: PMC8211915 DOI: 10.1016/j.ibneur.2021.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/03/2021] [Indexed: 12/02/2022] Open
Abstract
INTRODUCTION One of the most compelling causes of perinatal mortality and morbidity is intrauterine growth restriction (IUGR). IUGR is linked with numerous health challenges that last lifelong, including neurodevelopmental impairment and a high incidence of brain dysfunction. There is mounting evidence that places the glutamatergic system at the center of the neurobiology and treatment of neurological diseases. Therefore, this study investigated the effects of postnatal glutathione intervention on the spatial memory and the expressions of vesicular glutamate transporter 1 (VGLUT1) in the hippocampus and the cerebellar cortex of Nω-nitro-L-arginine methyl (L-NAME)-induced rat model of IUGR. MATERIALS AND METHOD Twelve adult female rats were divided into Control and L-NAME groups; each containing 6 female rats. The control group received a single daily dose of normal saline while the L-NAME group was administered 50 mg/kg L-NAME daily from gestational day 9 until parturition. Offspring of the control rats were given free access to feeds while offspring from the L-NAME group were assigned into 3 groups: G1: given free access to feeds; G2 and G3 were administered 1.5 mg/kg body weight of glutathione from postnatal day (PND) 4-9 and PND 25-31 respectively. At the end of the intervention, Y-maze was conducted, and the rats euthanized on PND 35. The brain sections were processed, and immunofluorescence staining was performed using the Vectafluor Excel R.T.U Antibody kit. RESULTS IUGR caused a significant 31.1% decrease in spontaneous alternation percentage (SAP), while early treatment with glutathione at PND 4-9 significantly (p < 0.01) increased SAP, while late treatment at PND 25-9 significantly decreased SAP compared to IUGR group. Furthermore, IUGR caused significant (p < 0.001) downregulation in corrected total cell fluorescence (CTCF) of VGLUT1 in both the hippocampus and cerebellar cortex. While treatment with glutathione caused upregulation in CTCF of VGLUT1 in the hippocampus and the cerebellar cortex. CONCLUSION Our results showed that early intervention with glutathione has significant therapeutic potential via upregulation of VGLUT1 expression in both hippocampus and cerebellar cortex, which positively correlated with enhanced spatial memory in IUGR rat model.
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Affiliation(s)
| | | | | | | | - Thajasvarie Naicker
- Optics and Imaging Centre, University of KwaZulu-Natal., Durban, South Africa
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Lisco G, Giagulli VA, Iovino M, Guastamacchia E, Pergola GD, Triggiani V. Endocrine-Disrupting Chemicals: Introduction to the Theme. Endocr Metab Immune Disord Drug Targets 2021; 22:677-685. [PMID: 33847259 DOI: 10.2174/1871530321666210413124425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/03/2021] [Accepted: 02/18/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Endocrine-disrupting chemicals (EDCs) are natural or synthetic compounds deriving from different human activities and are widely spread into the environment, contributing to indoor and outdoor pollution. EDCs may be conveyed by food and water consumption and skin, airways, placental, and breastfeeding. Upon entering the circulation, they can interfere with endocrine system homeostasis by several mechanisms. AIM In this narrative review, the authors overviewed the leading mechanisms by which EDCs interact and disrupt the endocrine system, leading to possible human health concerns. RESULTS The leading mechanisms of EDCs-related toxicity have been illustrated in in vitro studies and animal models and may be summarized as follows: receptor agonism and antagonism; modulation of hormone receptor expression; interference with signal transduction in hormone-responsive cells; epigenetic modifications in hormone-producing or hormone-responsive cells; interference with hormone synthesis; interference with hormone transport across cell membranes; interference with hormone metabolism or clearance; interference with the destiny of hormone-producing or hormone-responsive cells. DISCUSSION Despite these well-defined mechanisms, some limitations do not allow for conclusive assumptions. Indeed, epidemiological and ecological studies are currently lacking and usually refer to a specific cluster of patients (occupational exposure). Methodological aspects could further complicate the issue since these studies could require a long time to provide useful information. The lack of a real unexposed group in environmental conditions, possible interference of EDCs mixture on biological results, and unpredictable dose-response curves for some EDCs should also be considered significant limitations. CONCLUSION Given these limitations, specific observational and long-term studies are needed to identify at-risk populations for adequate treatment of exposed patients and effective prevention plans against excessive exposure to EDCs.
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Affiliation(s)
- Giuseppe Lisco
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases. University of Bari "Aldo Moro", School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
| | - Vito Angelo Giagulli
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases. University of Bari "Aldo Moro", School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
| | - Michele Iovino
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases. University of Bari "Aldo Moro", School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
| | - Edoardo Guastamacchia
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases. University of Bari "Aldo Moro", School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
| | - Giovanni De Pergola
- Clinical Nutrition Unit, Medical Oncology, Department of Internal Medicine and Clinical Oncology, University of Bari, School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
| | - Vincenzo Triggiani
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases. University of Bari "Aldo Moro", School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari. Italy
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Urbani C, Mattiello A, Ferri G, Raggi F, Russo D, Marconcini G, Cappellani D, Manetti L, Marcocci C, Cardarelli F, Bogazzi F. PCB153 reduces apoptosis in primary cultures of murine pituitary cells through the activation of NF-κB mediated by PI3K/Akt. Mol Cell Endocrinol 2021; 520:111090. [PMID: 33242503 DOI: 10.1016/j.mce.2020.111090] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/02/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent pollutants involved in human tumorigenesis. PCB153 is a ubiquitous non-dioxin-like PCB with proliferative and anti-apoptotic effects. To explore the impact of PCB153 in the survival of pituitary cells, we exposed murine pituitary primary cells to PCB153 10 μM for 24 h. Apoptosis was assessed by RT-qPCR, Western-blot, immunoprecipitation, caspase activity, and immunofluorescence. We found that PCB153 decreased pituitary apoptosis through both the extrinsic and intrinsic pathways. PCB153 reduced the level of the pro-apoptotic protein p38-MAPK. Otherwise, PCB153 activated PI3K/Akt and Erk1/2 pathways and enhanced the expression and nuclear translocation of NF-κB. Cotreatments with specific inhibitors revealed that only PI3K/Akt changed the caspase-3 expression and NF-κB activation induced by PCB153. Also, PCB153 decreased the expression of the pro-apoptotic and pro-senescent cyclins p53 and p21. In summary, exposure to PCB153 leads to a downregulation of apoptosis in the pituitary driven by a PI3K/Akt-mediated activation of NF-κB.
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Affiliation(s)
- Claudio Urbani
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Alessandro Mattiello
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Gianmarco Ferri
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Francesco Raggi
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Dania Russo
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Giulia Marconcini
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Daniele Cappellani
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Luca Manetti
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Claudio Marcocci
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy
| | - Francesco Cardarelli
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Fausto Bogazzi
- Department of Clinical and Experimental Medicine, University of Pisa, via Savi, 10, 56126, Pisa, Italy.
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Heiger-Bernays WJ, Tomsho KS, Basra K, Petropoulos ZE, Crawford K, Martinez A, Hornbuckle KC, Scammell MK. Human health risks due to airborne polychlorinated biphenyls are highest in New Bedford Harbor communities living closest to the harbor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 710:135576. [PMID: 31785914 PMCID: PMC7015809 DOI: 10.1016/j.scitotenv.2019.135576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 11/12/2019] [Accepted: 11/15/2019] [Indexed: 04/14/2023]
Abstract
In response to concerns raised by communities surrounding the New Bedford Harbor Superfund site, we completed a field and modeling study that concluded the harbor is the primary source of polychlorinated biphenyls (PCBs) in air around the harbor. The follow-up question from residents was whether the PCBs measured in air pose a risk to their health. The US Environmental Protection Agency focuses their site-specific, risk-based decisions for site clean-up on cancers. We focused our assessment on the non-cancer effects on the thyroid based on the congener specific patterns and concentrations of PCBs measured in air near and distant to the harbor. Human and animal studies of PCB-induced effects on the thyroid provide evidence to support our analysis. Drawing from the published toxicological data, we used a Margin of Exposure (MOE) approach to derive a human-equivalent concentration in air associated with human health effects on the thyroid. Based on the MOEs calculated herein, evaluation of the MOE indicates that changes in thyroid hormone levels are possible among people living adjacent to the Harbor. Changes in thyroid hormone levels are more likely among people who live near the harbor compared to residents living in areas distant from the harbor. This risk assessment documents potential health risks associated with proximity to a marine Superfund Site using site-specific ambient air PCB congener data.
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Affiliation(s)
- Wendy J Heiger-Bernays
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States.
| | - Kathryn Scott Tomsho
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States
| | - Komal Basra
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States
| | - Zoe E Petropoulos
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States
| | - Kathryn Crawford
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States
| | - Andres Martinez
- Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, 4105 Seamans Center for the Engineering Arts and Sciences, The University of Iowa, Iowa City, IA 52242, United States
| | - Keri C Hornbuckle
- Department of Civil & Environmental Engineering, IIHR-Hydroscience and Engineering, 4105 Seamans Center for the Engineering Arts and Sciences, The University of Iowa, Iowa City, IA 52242, United States
| | - Madeleine K Scammell
- Boston University School of Public Health, Department of Environmental Health, 715 Albany St., Talbot Building, Boston, MA 02118, United States
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Dufour P, Pirard C, Petrossians P, Beckers A, Charlier C. Association between mixture of persistent organic pollutants and thyroid pathologies in a Belgian population. ENVIRONMENTAL RESEARCH 2020; 181:108922. [PMID: 31759644 DOI: 10.1016/j.envres.2019.108922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/24/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
Previous years, the incidence of autoimmune thyroid diseases has increased worldwide. The presence of many pollutants in the environment suspected to be thyroid disruptors may have contributed to the observed increase. Unfortunately, the results from epidemiological studies assessing the association between pollution and thyroid disorders remain inconsistent, maybe due to a nearly complete neglect of the mixture effect. The blood levels of 12 brominated flame retardants, 3 polychlorinated biphenyls, 16 organochlorine pesticides, 7 perfluoroalkyl substances and 16 phenolic organohalogens were measured in 35 hypothyroid and 44 hyperthyroid volunteers and in 160 individuals from the general population designed as controls. Weighted quantile sum (WQS) regressions were performed to compute indexes representing the mixture of POPs, and we assessed the relations with thyroid disorders. Nineteen pollutants were detected in more than 40% of the individuals and were thus included in the WQS indexes. The WQS index was statistically significantly associated with an increased odds of hypothyroidism (odds ratio (OR) = 98.1; 95% CI: 5.51-1747) with the highest weights attributed to PCB 138 (w = 0.210), 3-OH-CB 180 (w = 0.197), 4-OH-CB 146 (w = 0.188), 4',4-DDE (w = 0.156) while there were no evidence of a relation with increased odds of hyperthyroidism. Given the relative low number of individuals included in the present investigation, standard WQS methodology could not be used, this study should thus be considered as a preliminary, hypothesis-generating study. Nevertheless, these results highlighted the importance of considering the potential effect of chemical mixture when studying endocrine disruptors.
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Affiliation(s)
- Patrice Dufour
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg), CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg), CHU (B35), 4000, Liege, Belgium.
| | - Catherine Pirard
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg), CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg), CHU (B35), 4000, Liege, Belgium
| | - Patrick Petrossians
- Department of Endocrinology, University of Liege (ULg), CHU (BE 035), 4000, Liege, Belgium
| | - Albert Beckers
- Department of Endocrinology, University of Liege (ULg), CHU (BE 035), 4000, Liege, Belgium
| | - Corinne Charlier
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg), CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg), CHU (B35), 4000, Liege, Belgium
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La Merrill MA, Vandenberg LN, Smith MT, Goodson W, Browne P, Patisaul HB, Guyton KZ, Kortenkamp A, Cogliano VJ, Woodruff TJ, Rieswijk L, Sone H, Korach KS, Gore AC, Zeise L, Zoeller RT. Consensus on the key characteristics of endocrine-disrupting chemicals as a basis for hazard identification. Nat Rev Endocrinol 2020; 16:45-57. [PMID: 31719706 PMCID: PMC6902641 DOI: 10.1038/s41574-019-0273-8] [Citation(s) in RCA: 373] [Impact Index Per Article: 93.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/02/2019] [Indexed: 12/11/2022]
Abstract
Endocrine-disrupting chemicals (EDCs) are exogenous chemicals that interfere with hormone action, thereby increasing the risk of adverse health outcomes, including cancer, reproductive impairment, cognitive deficits and obesity. A complex literature of mechanistic studies provides evidence on the hazards of EDC exposure, yet there is no widely accepted systematic method to integrate these data to help identify EDC hazards. Inspired by work to improve hazard identification of carcinogens using key characteristics (KCs), we have developed ten KCs of EDCs based on our knowledge of hormone actions and EDC effects. In this Expert Consensus Statement, we describe the logic by which these KCs are identified and the assays that could be used to assess several of these KCs. We reflect on how these ten KCs can be used to identify, organize and utilize mechanistic data when evaluating chemicals as EDCs, and we use diethylstilbestrol, bisphenol A and perchlorate as examples to illustrate this approach.
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Affiliation(s)
- Michele A La Merrill
- Department of Environmental Toxicology, University of California, Davis, CA, USA.
| | - Laura N Vandenberg
- Department of Environmental Health Science, School of Public Health and Health Sciences, University of Masschusetts, Amherst, MA, USA
| | - Martyn T Smith
- School of Public Health, University of California, Berkeley, CA, USA
| | - William Goodson
- California Pacific Medical Center Research Institute, Sutter Hospital, San Francisco, CA, USA
| | - Patience Browne
- Environmental Directorate, Organisation for Economic Co-operation and Development, Paris, France
| | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Kathryn Z Guyton
- International Agency for Research on Cancer, World Health Organization, Lyon, France
| | | | - Vincent J Cogliano
- Office of the Science Advisor, United States Environmental Protection Agency, Washington, DC, USA
| | - Tracey J Woodruff
- Program on Reproductive Health and the Environment, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Linda Rieswijk
- School of Public Health, University of California, Berkeley, CA, USA
- Institute of Data Science, Maastricht University, Maastricht, Netherlands
| | - Hideko Sone
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Ibaraki, Japan
| | - Kenneth S Korach
- Receptor Biology, Section Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Science, Durham, NC, USA
| | - Andrea C Gore
- Division of Pharmacology and Toxicology, University of Texas at Austin, Austin, TX, USA
| | - Lauren Zeise
- Office of the Director, Office of Environmental Health Hazard Assessment of the California Environmental Protection Agency, Sacramento, CA, USA
| | - R Thomas Zoeller
- Biology Department, University of Masschusetts, Amherst, MA, USA
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Wahlang B, Jin J, Hardesty JE, Head KZ, Shi H, Falkner KC, Prough RA, Klinge CM, Cave MC. Identifying sex differences arising from polychlorinated biphenyl exposures in toxicant-associated liver disease. Food Chem Toxicol 2019; 129:64-76. [PMID: 31026535 DOI: 10.1016/j.fct.2019.04.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/24/2019] [Accepted: 04/06/2019] [Indexed: 12/14/2022]
Abstract
Exposures to persistent environmental pollutants like polychlorinated biphenyls (PCBs) has been associated with liver diseases such as toxicant-associated steatohepatitis (TASH). However, previously published PCB hepatotoxicity studies evaluated mostly male animal models. Moreover, epidemiologic studies on PCB-exposed cohorts evaluating sex differences are scarce. Therefore, the objective of this study was to examine hepato-toxicological responses of PCB exposures in the context of sex-dependent outcomes. Male and female C57Bl/6 mice were exposed to Aroclor 1260 (20 mg/kg), and PCB126 (20 μg/kg), by gavage for two weeks. Female mice appeared to be more sensitive to PCB-induced hepatotoxic effects as manifested by increased liver injury markers, namely, hepatic Serpine1 expression. Additionally, compared to their male counterparts, PCB-exposed females exhibited dysregulated hepatic gene expression favoring lipid accumulation rather than lipid breakdown; accompanied by dyslipidemia. Sex differences were also observed in the expression and activation of PCB targets such as the epidermal growth factor receptor (EGFR) while PCB-induced pancreatic toxicity was similar in both sexes. Importantly, PCB exposure appeared to cause pro-androgenic, anti-estrogenic along with sex-dependent thyroid hormone effects. The overall findings demonstrated that the observed PCB-mediated hepatotoxicity was sex-dependent; confirming the existence of sex differences in environmental exposure-induced markers of TASH and warrants further investigation.
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Affiliation(s)
- Banrida Wahlang
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA; UofL Superfund Research Center, University of Louisville, Louisville, KY, USA
| | - Jian Jin
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Josiah E Hardesty
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Kimberly Z Head
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Hongxue Shi
- Department of Cell & Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - K Cameron Falkner
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Russell A Prough
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Carolyn M Klinge
- Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Matthew C Cave
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, School of Medicine, University of Louisville, Louisville, KY, USA; UofL Superfund Research Center, University of Louisville, Louisville, KY, USA; Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY, USA; Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, USA; Robley Rex Veterans Affairs Medical Center, Louisville, KY, USA.
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Klinefelter K, Hooven MK, Bates C, Colter BT, Dailey A, Infante SK, Kania-Korwel I, Lehmler HJ, López-Juárez A, Ludwig CP, Curran CP. Genetic differences in the aryl hydrocarbon receptor and CYP1A2 affect sensitivity to developmental polychlorinated biphenyl exposure in mice: relevance to studies of human neurological disorders. Mamm Genome 2017; 29:112-127. [PMID: 29197979 DOI: 10.1007/s00335-017-9728-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/28/2017] [Indexed: 01/28/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that remain a human health concern with newly discovered sources of contamination and ongoing bioaccumulation and biomagnification. Children exposed during early brain development are at highest risk of neurological deficits, but highly exposed adults reportedly have an increased risk of Parkinson's disease. Our previous studies found allelic differences in the aryl hydrocarbon receptor and cytochrome P450 1A2 (CYP1A2) affect sensitivity to developmental PCB exposure, resulting in cognitive deficits and motor dysfunction. High-affinity Ahr b Cyp1a2(-/-) mice were most sensitive compared with poor-affinity Ahr d Cyp1a2(-/-) and wild-type Ahr b Cyp1a2(+/+) mice. Our follow-up studies assessed biochemical, histological, and gene expression changes to identify the brain regions and pathways affected. We also measured PCB and metabolite levels in tissues to determine if genotype altered toxicokinetics. We found evidence of AHR-mediated toxicity with reduced thymus and spleen weights and significantly reduced thyroxine at P14 in PCB-exposed pups. In the brain, the greatest changes were seen in the cerebellum where a foliation defect was over-represented in Cyp1a2(-/-) mice. In contrast, we found no difference in tyrosine hydroxylase immunostaining in the striatum. Gene expression patterns varied across the three genotypes, but there was clear evidence of AHR activation. Distribution of parent PCB congeners also varied by genotype with strikingly high levels of PCB 77 in poor-affinity Ahr d Cyp1a2(-/-) while Ahr b Cyp1a2(+/+) mice effectively sequestered coplanar PCBs in the liver. Together, our data suggest that the AHR pathway plays a role in developmental PCB neurotoxicity, but we found little evidence that developmental exposure is a risk factor for Parkinson's disease.
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Affiliation(s)
- Kelsey Klinefelter
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Molly Kromme Hooven
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Chloe Bates
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA
| | - Breann T Colter
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA
| | - Alexandra Dailey
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA
| | - Smitha Krishnan Infante
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA
| | - Izabela Kania-Korwel
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Alejandro López-Juárez
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Clare Pickering Ludwig
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA
| | - Christine Perdan Curran
- Department of Biological Sciences, Northern Kentucky University, SC344 Nunn Drive, Highland Heights, KY, 41076, USA.
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Lau G, Walter K, Kass P, Puschner B. Comparison of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the serum of hypothyroxinemic and euthyroid dogs. PeerJ 2017; 5:e3780. [PMID: 28924500 PMCID: PMC5600179 DOI: 10.7717/peerj.3780] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 08/17/2017] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To determine the profile of 14 polybrominated diphenyl ethers (PBDEs) and 23 polychlorinated biphenyls (PCBs) in serum of domestic canines and whether this was predictive of thyroid hormone status. SAMPLES Serum samples were collected from 51 client-owned dogs visiting the University of California Davis William R. Pritchard Veterinary Medical Teaching Hospital during 2012 to 2016 for routine appointments. Fifteen dogs were diagnosed with hypothyroxinemia while 36 were euthyroid. PROCEDURES Concentrations of PBDEs and PCBs in canine serum samples were measured by gas chromatography mass spectrometry. Logistic regression analysis was used to determine the association between the presence/absence of canine hypothyroxinemia and the serum concentration of individual PBDE or PCB congeners. RESULTS The median concentrations of total PBDE and PCB congeners in the hypothyroxinemic group were 660 and 1,371 ng/g lipid, respectively, which were higher than concentrations detected in the control group. However, logistic regression analysis determined that current concentrations of PBDEs and PCBs in canines were not significantly associated with hypothyroxinemia. BDE 183 was the only congener showing near significance (p = 0.068). CONCLUSIONS PBDE and PCB congeners were detected in all canine samples confirming ongoing exposure to these pollutants. Because household dogs share the human environment, they may serve as biosentinels of human exposure to these contaminants.
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Affiliation(s)
- Grace Lau
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
| | - Kyla Walter
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
| | - Philip Kass
- Department of Population Health and Reproduction, University of California, Davis, CA, United States of America
| | - Birgit Puschner
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
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Lau G, Walter K, Kass P, Puschner B. Comparison of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the serum of hypothyroxinemic and euthyroid dogs. PeerJ 2017. [PMID: 28924500 DOI: 10.7717/peeq.3780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023] Open
Abstract
OBJECTIVE To determine the profile of 14 polybrominated diphenyl ethers (PBDEs) and 23 polychlorinated biphenyls (PCBs) in serum of domestic canines and whether this was predictive of thyroid hormone status. SAMPLES Serum samples were collected from 51 client-owned dogs visiting the University of California Davis William R. Pritchard Veterinary Medical Teaching Hospital during 2012 to 2016 for routine appointments. Fifteen dogs were diagnosed with hypothyroxinemia while 36 were euthyroid. PROCEDURES Concentrations of PBDEs and PCBs in canine serum samples were measured by gas chromatography mass spectrometry. Logistic regression analysis was used to determine the association between the presence/absence of canine hypothyroxinemia and the serum concentration of individual PBDE or PCB congeners. RESULTS The median concentrations of total PBDE and PCB congeners in the hypothyroxinemic group were 660 and 1,371 ng/g lipid, respectively, which were higher than concentrations detected in the control group. However, logistic regression analysis determined that current concentrations of PBDEs and PCBs in canines were not significantly associated with hypothyroxinemia. BDE 183 was the only congener showing near significance (p = 0.068). CONCLUSIONS PBDE and PCB congeners were detected in all canine samples confirming ongoing exposure to these pollutants. Because household dogs share the human environment, they may serve as biosentinels of human exposure to these contaminants.
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Affiliation(s)
- Grace Lau
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
| | - Kyla Walter
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
| | - Philip Kass
- Department of Population Health and Reproduction, University of California, Davis, CA, United States of America
| | - Birgit Puschner
- Department of Molecular Biosciences, University of California, Davis, CA, United States of America
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Sobolewski M, Allen JL, Morris-Schaffer K, Klocke C, Conrad K, Cory-Slechta DA. A novel, ecologically relevant, highly preferred, and non-invasive means of oral substance administration for rodents. Neurotoxicol Teratol 2016; 56:75-80. [PMID: 27094606 DOI: 10.1016/j.ntt.2016.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 04/07/2016] [Accepted: 04/12/2016] [Indexed: 01/01/2023]
Abstract
Prenatal stress and nutrition are well-known to alter a broad range of physiological systems, notably metabolic, endocrine and neurobehavioral function. Commonly used methods for oral administration of xenobiotics can, by acting as a stressor or altering normal nutrition intake, alter these physiological systems as well. Taken together, oral administration methods may unintentionally introduce confounding physiological effects that can mask or enhance toxicity of xenobiotics, particularly if they share biological targets. Consequently, it should be preferable to develop alternative methods without these potential confounds. The aim of this study was to determine the suitability of mealworms as an alternative treat-based method to deliver xenobiotics via the orogastric route. Accurate oral administration is contingent on motivation and preference; mice reliably preferred mealworms over wafer cookie treats. Further, ingestion of wafer cookies significantly increased mouse blood glucose levels, whereas unaltered mealworms produced no such change. Mealworms functioned effectively to orally administer glucose, as glucose-spiked mealworms produced a rise in blood glucose equivalent to the ingestion of the wafer cookie. Mealworms did not interfere with the physiological function of orally administered d-amphetamine, as both mealworm and oral gavage administered d-amphetamine showed similar alterations in locomotor behavior (mice did not fully consume d-amphetamine-dosed cookies and thus could not be compared). Collectively, the findings indicate that mealworms are a preferred and readily consumed treat, which importantly mimics environmental-relevant nutritional intake, and mealworms per se do not alter glucose metabolic pathways. Additionally, mealworms accurately delivered xenobiotics into blood circulation and did not interfere with the physiological function of administered xenobiotics. Thus mealworm-based oral administration may be a preferable and accurate route of xenobiotic administration that eliminates physiological alterations associated with other methods of delivery.
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Affiliation(s)
- Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
| | - Joshua L Allen
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
| | - Keith Morris-Schaffer
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
| | - Carolyn Klocke
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
| | - Katherine Conrad
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
| | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester, 575 Elmwood Ave, Box EHSC, Rochester, NY 14642, United States.
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Chen H, Zhang X, Jia X, Li Q, Su Q, Wang W, Liu Z. Thyroid disrupting effects of polychlorinated biphenyls in ovariectomized rats: A benchmark dose analysis. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:733-740. [PMID: 26432769 DOI: 10.1016/j.etap.2015.08.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 06/05/2023]
Abstract
Polychlorinated biphenyls (PCBs) are proved endocrine disrupting potentials. Reference points (RP) for PCBs are derived from dose-response relationship analysis by using the traditional no observed adverse effect or lowest observed adverse effect level (NOAEL/LOAEL) methods, or a more advanced benchmark dose (BMD) method. In present study, toxicological RP for PCBs' thyroid disruption was established and compared between NOAEL/LOAEL and BMD method in an ovariectomized (OVX) rat model. Sham and OVX controls were given corn oil while other OVX groups were administered with 0.1, 1.0, 5.0, and 10.0mg/kg bw of PCBs (aroclor 1254) respectively by gavage. Body weight change, liver type I 5'-deiodinase (5'-DI) activity, serum total thyroxine (tT4), triiodothyroxine (tT3), thyroid stimulating hormones (TSH), and thyroid histopathological changes were measured and analyzed. In PCBs-treated groups, serum tT4, tT3, TSH, and histopathological examinations showed significant changes with a dose-dependent manner compared with those in OVX control (P<0.05). The toxicological RP for PCBs affecting thyroid function of OVX rats was 0.02 mg/kg'bw based on BMD analysis.
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Affiliation(s)
- Hao Chen
- Key laboratory of food safety risk assessment, Ministry of Health (China National Center for Food Safety Risk Assessment), 100022, Beijing, China; Chinese Center for Disease Control and Prevention, 100021, Beijing, China
| | - Xiaopeng Zhang
- Key laboratory of food safety risk assessment, Ministry of Health (China National Center for Food Safety Risk Assessment), 100022, Beijing, China
| | - Xudong Jia
- Key laboratory of food safety risk assessment, Ministry of Health (China National Center for Food Safety Risk Assessment), 100022, Beijing, China
| | - Qian Li
- Sichuan University, Sichuan, 610041, China
| | - Qing Su
- Southwest University, Chongqing, 400716, China
| | - Wei Wang
- Key laboratory of food safety risk assessment, Ministry of Health (China National Center for Food Safety Risk Assessment), 100022, Beijing, China
| | - Zhaoping Liu
- Key laboratory of food safety risk assessment, Ministry of Health (China National Center for Food Safety Risk Assessment), 100022, Beijing, China.
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NIEHS/FDA CLARITY-BPA research program update. Reprod Toxicol 2015; 58:33-44. [PMID: 26232693 PMCID: PMC5545120 DOI: 10.1016/j.reprotox.2015.07.075] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 07/13/2015] [Accepted: 07/17/2015] [Indexed: 01/03/2023]
Abstract
Bisphenol A (BPA) is a chemical used in the production of numerous consumer products resulting in potential daily human exposure to this chemical. The FDA previously evaluated the body of BPA toxicology data and determined that BPA is safe at current exposure levels. Although consistent with the assessment of some other regulatory agencies around the world, this determination of BPA safety continues to be debated in scientific and popular publications, resulting in conflicting messages to the public. Thus, the National Toxicology Program (NTP), National Institute of Environmental Health Sciences (NIEHS), and U.S Food and Drug Administration (FDA) developed a consortium-based research program to link more effectively a variety of hypothesis-based research investigations and guideline-compliant safety testing with BPA. This collaboration is known as the Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA). This paper provides a detailed description of the conduct of the study and a midterm update on progress of the CLARITY-BPA research program.
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Wadzinski TL, Geromini K, McKinley Brewer J, Bansal R, Abdelouahab N, Langlois MF, Takser L, Zoeller RT. Endocrine disruption in human placenta: expression of the dioxin-inducible enzyme, CYP1A1, is correlated with that of thyroid hormone-regulated genes. J Clin Endocrinol Metab 2014; 99:E2735-43. [PMID: 25299844 PMCID: PMC4255108 DOI: 10.1210/jc.2014-2629] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Thyroid hormone (TH) is essential for normal development; therefore, disruption of TH action by a number of industrial chemicals is critical to identify. Several chemicals including polychlorinated biphenyls are metabolized by the dioxin-inducible enzyme CYP1A1; some of their metabolites can interact with the TH receptor. In animals, this mechanism is reflected by a strong correlation between the expression of CYP1A1 mRNA and TH-regulated mRNAs. If this mechanism occurs in humans, we expect that CYP1A1 expression will be positively correlated with the expression of genes regulated by TH. OBJECTIVE The objective of the study was to test the hypothesis that CYP1A1 mRNA expression is correlated with TH-regulated mRNAs in human placenta. METHODS One hundred sixty-four placental samples from pregnancies with no thyroid disease were obtained from the GESTE study (Sherbrooke, Québec, Canada). Maternal and cord blood TH levels were measured at birth. The mRNA levels of CYP1A1 and placental TH receptor targets [placental lactogen (PL) and GH-V] were quantitated by quantitative PCR. RESULTS CYP1A1 mRNA abundance varied 5-fold across 132 placental samples that had detectable CYP1A1 mRNA. CYP1A1 mRNA was positively correlated with PL (r = 0.64; P < .0001) and GH-V (P < .0001, r = 0.62) mRNA. PL and GH-V mRNA were correlated with each other (r = 0.95; P < .0001), suggesting a common activator. The mRNAs not regulated by TH were not correlated with CYP1A1 expression. CONCLUSIONS CYP1A1 mRNA expression is strongly associated with the expression of TH-regulated target gene mRNAs in human placenta, consistent with the endocrine-disrupting action of metabolites produced by CYP1A1.
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Affiliation(s)
- Thomas L Wadzinski
- Department of Biology (T.L.W., K.G., J.M.B., R.B., R.T.Z.), University of Massachusetts Amherst, Amherst, Massachusetts 01003; Department of Pediatrics (T.L.W.), Baystate Medical Center, Springfield, Massachusetts 01199; and Department of Pediatrics (N.A., L.T.), Faculty of Medicine, and Department of Medicine (M.-F.L.), Endocrinology Service, Faculty of Medicine, University of Sherbrooke, Sherbrooke, Qéubec, Canada J1H SN4
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Paquette MA, Atlas E, Wade MG, Yauk CL. Thyroid hormone response element half-site organization and its effect on thyroid hormone mediated transcription. PLoS One 2014; 9:e101155. [PMID: 24971931 PMCID: PMC4074170 DOI: 10.1371/journal.pone.0101155] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/03/2014] [Indexed: 02/03/2023] Open
Abstract
Thyroid hormone (TH) exerts its effects by binding to the thyroid hormone receptor (TR), which binds to TH response elements (TREs) to regulate target gene expression. We investigated the relative ability of liganded homodimers TR and retinoid X receptor (RXR), and the heterodimer TR/RXR, to regulate gene expression for the TRE half-site organizations: direct repeat 4 (DR4), inverted repeat 0 (IR0) and everted repeat 6 (ER6). Luciferase reporter assays using a DR4 TRE suggest that both the TR homodimer and TR/RXR heterodimer regulate luciferase expression in the presence of their respective ligands. However, in the presence of the IR0 TRE, transfection with TR/RXR and RXR alone increased luciferase activity and there was no effect of TR alone. The presence of 9-cis-retinoic acid was necessary for luciferase expression, whereas TH treatment alone was insufficient. For the ER6 TRE, transfection with TR/RXR, TR alone and RXR alone (in the presence of their respective ligands) all caused a significant increase in luciferase activity. When both ligands were present, transfection with both TR/RXR caused more activation. Finally, we investigated the efficacy of the TR-antagonist 1–850 in inhibiting transcription by TR or TR/RXR at DR4 and ER6 TREs. We found that 1–850 did not suppress luciferase activation in the presence of TR/RXR for the ER6 TRE, suggesting conformational changes of the ligand binding domain of the TR when bound to different TRE half-site organizations. Collectively, the findings indicate that there are fundamental differences between TRE configurations that affect nuclear receptor interactions with the response element and ability to bind ligands and antagonists.
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Affiliation(s)
- Martin A. Paquette
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Mike G. Wade
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
- * E-mail:
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Naveau E, Pinson A, Gérard A, Nguyen L, Charlier C, Thomé JP, Zoeller RT, Bourguignon JP, Parent AS. Alteration of rat fetal cerebral cortex development after prenatal exposure to polychlorinated biphenyls. PLoS One 2014; 9:e91903. [PMID: 24642964 PMCID: PMC3958407 DOI: 10.1371/journal.pone.0091903] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 02/17/2014] [Indexed: 01/23/2023] Open
Abstract
Polychlorinated biphenyls (PCBs) are environmental contaminants that persist in environment and human tissues. Perinatal exposure to these endocrine disruptors causes cognitive deficits and learning disabilities in children. These effects may involve their ability to interfere with thyroid hormone (TH) action. We tested the hypothesis that developmental exposure to PCBs can concomitantly alter TH levels and TH-regulated events during cerebral cortex development: progenitor proliferation, cell cycle exit and neuron migration. Pregnant rats exposed to the commercial PCB mixture Aroclor 1254 ended gestation with reduced total and free serum thyroxine levels. Exposure to Aroclor 1254 increased cell cycle exit of the neuronal progenitors and delayed radial neuronal migration in the fetal cortex. Progenitor cell proliferation, cell death and differentiation rate were not altered by prenatal exposure to PCBs. Given that PCBs remain ubiquitous, though diminishing, contaminants in human systems, it is important that we further understand their deleterious effects in the brain.
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Affiliation(s)
- Elise Naveau
- Developmental Neuroendocrinology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
| | - Anneline Pinson
- Developmental Neuroendocrinology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
| | - Arlette Gérard
- Developmental Neuroendocrinology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
| | - Laurent Nguyen
- Developmental Neurobiology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
| | - Corinne Charlier
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liège, CHU, Liège, Belgium
| | - Jean-Pierre Thomé
- Laboratory of Animal Ecology and Ecotoxicology (LEAE, CART), University of Liège, Liège, Belgium
| | - R Thomas Zoeller
- Biology Department, University of Massachusetts, Morrill Science Center, Amherst, Massachusetts, United States of America
| | - Jean-Pierre Bourguignon
- Developmental Neuroendocrinology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
| | - Anne-Simone Parent
- Developmental Neuroendocrinology unit, GIGA Neurosciences, University of Liège, CHU, Liège, Belgium
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Bourguignon JP, Franssen D, Gérard A, Janssen S, Pinson A, Naveau E, Parent AS. Early neuroendocrine disruption in hypothalamus and hippocampus: developmental effects including female sexual maturation and implications for endocrine disrupting chemical screening. J Neuroendocrinol 2013; 25:1079-87. [PMID: 24028442 DOI: 10.1111/jne.12107] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/03/2013] [Accepted: 09/05/2013] [Indexed: 01/25/2023]
Abstract
The timing of puberty has been mainly studied in females for several reasons, including the possible evaluation of a precise timer (i.e. menarcheal age) and concerns with respect to the high prevalence of precocity in females as opposed to males. Human evidence of altered female pubertal timing after exposure to endocrine disrupting chemicals (EDCs) is equivocal. Among the limiting factors, most studies evaluate exposure to single EDCs at the time of puberty and hardly assess the impact of lifelong exposure to mixtures of EDCs. Some rodent and ovine studies indicate a possible role of foetal and neonatal exposure to EDCs, in accordance with the concept of an early origin of health and disease. Such effects possibly involve neuroendocrine mechanisms because the hypothalamus is a site where homeostasis of reproduction, as well as control of energy balance, is programmed and regulated. In our previous studies, pulsatile gonadotrophin-releasing hormone (GnRH) secretion control via oestrogen, glutamate and aryl hydrocarbon receptors was shown to be involved in the mechanism of sexual precocity after early postnatal exposure to the insecticide dichlorodiphenyltrichloroethane. Very recently, we have shown that neonatal exposure to the potent synthetic oestrogen diethylstilbestrol (DES) is followed by early or delayed puberty depending on the dose, with consistent changes in developmental increase of GnRH pulse frequency. Moreover, DES results in reduced leptin stimulation of GnRH secretion in vitro, an effect that is additive with prenatal food restriction. Thus, using puberty as an endpoint of the effects of EDC, it appears necessary to consider pre- and perinatal exposure to low doses and to pay attention to the other conditions of prenatal life, such as energy availability, keeping in mind the possibility that puberty could not only be advanced, but also delayed through neuroendocrine mechanisms.
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Affiliation(s)
- J-P Bourguignon
- Developmental Neuroendocrinology Unit, GIGA Neurosciences, University of Liège, Liège, Belgium; Department of Pediatrics, CHU, Liège, Belgium
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Fujimoto H, Woo GH, Morita R, Itahashi M, Akane H, Nishikawa A, Shibutani M. Increased cellular distribution of vimentin and ret in the cingulum of rat offspring after developmental exposure to decabromodiphenyl ether or 1,2,5,6,9,10-hexabromocyclododecane. J Toxicol Pathol 2013; 26:119-29. [PMID: 23914054 PMCID: PMC3695334 DOI: 10.1293/tox.26.119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 01/04/2013] [Indexed: 01/19/2023] Open
Abstract
Abstract: To determine effects of developmental exposure to brominated flame
retardants (BFRs), weak thyroid hormone disruptors, on white matter development, white
matter-specific global gene expression analysis was performed using microdissection
techniques and microarrays in male rats exposed maternally to decabromodiphenyl ether
(DBDE), one of the representative BFRs, at 10, 100 or 1000 ppm. Based on previous gene
expression profiles of developmental hypothyroidism and DBDE-exposed cases,
vimentin+ immature astrocytes and ret proto-oncogene (Ret)+
oligodendrocytes were immunohistochemically examined after developmental exposure to
representative BFRs, i.e., DBDE, 1,2,5,6,9,10-hexabromocyclododecane (HBCD; 100, 1000 or
10,000 ppm) and tetrabromobisphenol A (TBBPA; 100, 1000 or 10,000 ppm).
Vimentin+ and Ret+ cell populations increased at ≥ 100 ppm and ≥
10 ppm DBDE, respectively. Vimentin+ and Ret+ cells increased at ≥
1000 ppm HBCD, with no effect of TBBPA. The highest dose of DBDE and HBCD revealed subtle
fluctuations in serum thyroid-related hormone concentrations. Thus, DBDE and HBCD may
exert direct effects on glial cell development at ≥ middle doses. At high doses,
hypothyroidism may additionally be an inducing mechanism, although its contribution is
rather minor.
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Affiliation(s)
- Hitoshi Fujimoto
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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Saegusa Y, Fujimoto H, Woo GH, Ohishi T, Wang L, Mitsumori K, Nishikawa A, Shibutani M. Transient aberration of neuronal development in the hippocampal dentate gyrus after developmental exposure to brominated flame retardants in rats. Arch Toxicol 2012; 86:1431-42. [DOI: 10.1007/s00204-012-0824-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 02/27/2012] [Indexed: 11/25/2022]
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Ernest SR, Wade MG, Lalancette C, Ma YQ, Berger RG, Robaire B, Hales BF. Effects of chronic exposure to an environmentally relevant mixture of brominated flame retardants on the reproductive and thyroid system in adult male rats. Toxicol Sci 2012; 127:496-507. [PMID: 22387749 PMCID: PMC3355309 DOI: 10.1093/toxsci/kfs098] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brominated flame retardants (BFRs) are incorporated into a wide variety of consumer products, are readily released into home and work environments, and are present in house dust. Studies using animal models have revealed that exposure to polybrominated diphenyl ethers (PBDEs) may impair adult male reproductive function and thyroid hormone physiology. Such studies have generally characterized the outcome of acute or chronic exposure to a single BFR technical mixture or congener but not the impact of environmentally relevant BFR mixtures. We tested whether exposure to the BFRs found in house dust would have an adverse impact on the adult male rat reproductive system and thyroid function. Adult male Sprague Dawley rats were exposed to a complex BFR mixture composed of three commercial brominated diphenyl ethers (52.1% DE-71, 0.4% DE-79, and 44.2% decaBDE-209) and hexabromocyclododecane (3.3%), formulated to mimic the relative congener levels in house dust. BFRs were delivered in the diet at target doses of 0, 0.02, 0.2, 2, or 20 mg/kg/day for 70 days. Compared with controls, males exposed to the highest dose of BFRs displayed a significant increase in the weights of the kidneys and liver, which was accompanied by induction of CYP1A and CYP2B P450 hepatic drug–metabolizing enzymes. BFR exposure did not affect reproductive organ weights, serum testosterone levels, testicular function, or sperm DNA integrity. The highest dose caused thyroid toxicity as indicated by decreased serum thyroxine (T4) and hypertrophy of the thyroid gland epithelium. At lower doses, the thickness of the thyroid gland epithelium was reduced, but no changes in hormone levels (T4 and thyroid-stimulating hormone) were observed. Thus, exposure to BFRs affected liver and thyroid physiology but not male reproductive parameters.
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Affiliation(s)
- Sheila R Ernest
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada H3G 1Y6
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Zhang L, Sun YN, Li YM, Lin LX, Ye Y, Yan YQ, Chen ZP. Effect of different iodine nutrition on cerebellum Pcp-2 in rat offspring during lactation. Biol Trace Elem Res 2011; 143:1629-39. [PMID: 21344292 DOI: 10.1007/s12011-011-8991-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 02/01/2011] [Indexed: 12/29/2022]
Abstract
The thyroid functions of breastfed infants, as well as (indirectly) the development of their central nervous system, are dependent on the iodine status of the lactating mother. Purkinje cell protein-2 is a cell-specific marker of the cerebellum Purkinje cell and is a suitable indicator for observing the postnatal development of the cerebellum after birth. We measured the Purkinje cell protein-2 mRNA and protein levels in the rat cerebellum in the critical postnatal (14 days after birth) and maturation periods (28 days after birth) to determine the effect of different nutritional iodine levels on cerebellum growth in the offspring during lactation. We found that severe iodine deficiency resulted in thyroid dysfunction in lactating rats and their offspring on both 14 and 28 days, showing maternal total T(4) 16.7 ± 12.0 vs 36.4 ± 15.0, P < 0.05 (14 days) and 22.6 ± 18.7 vs 53.4 ± 9.4, P < 0.01 (28 days), and neonatal total T(4) 10.6 ± 2.3 vs 16.4 ± 4.7, P < 0.01(14 days) and 12.8 ± 2.9 vs 16.7 ± 3.4, P < 0.05 (28 days), respectively. The Purkinje cell protein-2 mRNA and its protein levels in offspring rats were significantly reduced that showed Purkinje cell protein-2 mRNA 1.12 ± 0.04 vs 2.25 ± 0.53, P < 0.05 (14 days) and 1.74 ± 0.94 vs 8.69 ± 2.71, P < 0.01 (28 days). However, mild iodine deficiency and excessive iodine maintained almost normal thyroid function in maternal and neonatal rats and normal Purkinje cell protein-2 mRNA and protein levels in offspring's cerebellum. We conclude that severe iodine deficiency could significantly reduce Purkinje cell protein-2 mRNA and its protein levels, indicating that the cerebellum development was retarded, but mild iodine deficiency and excessive iodine could maintain them at an approximately normal level by the mother's and offspring's compensations, especially by the mother's mammary glands.
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Affiliation(s)
- Lu Zhang
- Institute of Endocrinology, Tianjin Medical University, Key Lab of Hormones and Development, Ministry of Health, 22, Qi-Xiang-Tai Road, 300070, Tianjin, China
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Shibutani M, Fujimoto H, Woo GH, Inoue K, Takahashi M, Nishikawa A. Reply to Comment on “Impaired oligodendroglial development by decabromodiphenyl ether in rat offspring after maternal exposure from mid-gestation through lactation” [Reprod. Toxicol. 31(1) (2011) 86–94]. Reprod Toxicol 2011. [DOI: 10.1016/j.reprotox.2011.06.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Giera S, Bansal R, Ortiz-Toro TM, Taub DG, Zoeller RT. Individual polychlorinated biphenyl (PCB) congeners produce tissue- and gene-specific effects on thyroid hormone signaling during development. Endocrinology 2011; 152:2909-19. [PMID: 21540284 PMCID: PMC3115602 DOI: 10.1210/en.2010-1490] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Polychlorinated biphenyls (PCB) are industrial chemicals linked to developmental deficits that may be caused in part by disrupting thyroid hormone (TH) action by either reducing serum TH or interacting directly with the TH receptor (TR). Individual PCB congeners can activate the TR in vitro when the metabolic enzyme cytochrome P4501A1 (CYP1A1) is induced, suggesting that specific PCB metabolites act as TR agonists. To test this hypothesis in vivo, we compared two combinations of PCB congeners that either activate the TR (PCB 105 and 118) or not (PCB 138 and 153) in the presence or absence of a PCB congener (PCB 126) that induces CYP1A1 in vitro. Aroclor 1254 was used as a positive control, and a group treated with propylthiouracil was included to characterize the effects of low serum TH. We monitored the effects on TH signaling in several peripheral tissues by measuring the mRNA expression of well-known TH-response genes in these tissues. Aroclor 1254 and its component PCB 105/118/126 reduced total T(4) to the same extent as that of propylthiouracil but increased the expression of some TH target genes in liver. This effect was strongly correlated with CYP1A1 expression supporting the hypothesis that metabolism is necessary. Effects were gene and tissue specific, indicating that tissue-specific metabolism is an important component of PCB disruption of TH action and that PCB metabolites interact in complex ways with the TR. These are essential mechanisms to consider when evaluating the health risks of contaminant exposures, for both PCB and other polycyclic compounds known to interact with nuclear hormone receptors.
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Affiliation(s)
- Stefanie Giera
- Molecular and Cellular Biology Program, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
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Desaulniers D, Yagminas A, Chu I, Nakai J. Effects of anesthetics and terminal procedures on biochemical and hormonal measurements in polychlorinated biphenyl treated rats. Int J Toxicol 2011; 30:334-47. [PMID: 21444927 DOI: 10.1177/1091581810397774] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This investigation reports the effects of various terminal procedures, and how they modified the responses to a toxicant (polychlorinated biphenyls [A1254], 130 mg/kg/day × 5 days) administered by gavage to Sprague-Dawley male rats. Terminal procedures included exsanguination via the abdominal aorta under anesthesia (isoflurane inhalation or Equithesin injection), decapitation with or without anesthesia, or narcosis induced by carbon dioxide inhalation. Effects of repeated anesthesia were also tested. Terminal procedures induced confounding stress responses, particularly when Equithesin was used. The terminal procedures modified the conclusions about effects of A1254 on the concentrations of corticosterone, insulin, glucagon, glucose, alkaline phosphatase, lactate dehydrogenase, uric acid, and blood urea nitrogen, from nonstatistically significant to significant changes, and in the case of luteinizing hormone from a statistically significant increase to a significant decrease. Investigations of effects of toxicants should be designed and interpreted considering potential changes induced by the selection of a terminal procedure.
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Affiliation(s)
- Daniel Desaulniers
- Hazard Identification Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada.
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Parent AS, Naveau E, Gerard A, Bourguignon JP, Westbrook GL. Early developmental actions of endocrine disruptors on the hypothalamus, hippocampus, and cerebral cortex. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:328-45. [PMID: 21790315 PMCID: PMC3165012 DOI: 10.1080/10937404.2011.578556] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Sex steroids and thyroid hormones play a key role in the development of the central nervous system. The critical role of these hormonal systems may explain the sensitivity of the hypothalamus, the cerebral cortex, and the hippocampus to endocrine-disrupting chemicals (EDC). This review examines the evidence for endocrine disruption of glial-neuronal functions in the hypothalamus, hippocampus, and cerebral cortex. Focus was placed on two well-studied EDC, the insecticide dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB). DDT is involved in neuroendocrine disruption of the reproductive axis, whereas polychlorinated biphenyls (PCB) interact with both the thyroid hormone- and sex steroid-dependent systems and disturb the neuroendocrine control of reproduction and development of hippocampus and cortex. These results highlight the impact of EDC on the developing nervous system and the need for more research in this area.
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Affiliation(s)
- Anne-Simone Parent
- Developmental Neuroendocrinology Unit, GIGA Neurosciences, University of Liège, CHU Sart-Tilman, B4000 Liège, Belgium.
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Zoeller RT. Endocrine Disruption of the Thyroid and its Consequences in Development. RESEARCH AND PERSPECTIVES IN ENDOCRINE INTERACTIONS 2011. [DOI: 10.1007/978-3-642-22775-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Sharlin DS, Gilbert ME, Taylor MA, Ferguson DC, Zoeller RT. The nature of the compensatory response to low thyroid hormone in the developing brain. J Neuroendocrinol 2010; 22:153-65. [PMID: 20041985 DOI: 10.1111/j.1365-2826.2009.01947.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Thyroid hormone is essential for normal brain development, although the degree to which the developing brain is sensitive to small perturbations in serum thyroxin is not clear. An important concept related to this is that the developing brain possesses potent mechanisms to compensate for low serum thyroid hormone, and this concept is routinely employed in discussions concerning clinical treatments or public health. However, experimental studies have not directly tested whether (or the degree to which) putative compensatory mechanisms can ameliorate the consequences of small reductions in serum thyroxin (T(4)). To formally test this concept, we employed a model of graded T(4) reductions using doses of propylthiouracil (PTU) that were 200- to 67-fold lower than the dose traditionally used to produce hypothyroidism in rats. PTU produced a stepwise decrease in serum total T(4), and a stepwise increase in serum thyroid-stimulating hormone (TSH), in type 2 deiodinase mRNA expression and enzyme activity in the brain, and in the expression of the mRNA encoding the tri-iodothyronine (T(3)) transporter MCT8 in the postnatal day (P) 15 cortex. However, the mRNA encoding RC3/neurogranin, a direct target of T(3) action, exhibited a strong negative linear correlation with serum total T(4) despite these adaptive responses. In addition, single-cell analysis of RC3 mRNA levels in cortical neurones demonstrated that the co-expression of MCT8 did not alter the relationship between RC3 mRNA and serum T(4). These findings do not support the currently envisioned concept of the developing brain being capable of compensating for low T(4).
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Affiliation(s)
- D S Sharlin
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA
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