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Marty S, Beekhuijzen M, Charlton A, Hallmark N, Hannas BR, Jacobi S, Melching-Kollmuss S, Sauer UG, Sheets LP, Strauss V, Urbisch D, Botham PA, van Ravenzwaay B. Towards a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny - part II: how can key events of relevant adverse outcome pathways be addressed in toxicological assessments? Crit Rev Toxicol 2021; 51:328-358. [PMID: 34074207 DOI: 10.1080/10408444.2021.1910625] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The current understanding of thyroid-related adverse outcome pathways (AOPs) with adverse neurodevelopmental outcomes in mammals has been reviewed. This served to establish if standard rodent toxicity test methods and in vitro assays allow identifying thyroid-related modes-of-action potentially leading to adverse neurodevelopmental outcomes, and the human relevance of effects - in line with the European Commission's Endocrine Disruptor Criteria. The underlying hypothesis is that an understanding of the key events of relevant AOPs provides insight into differences in incidence, magnitude, or species sensitivity of adverse outcomes. The rodent studies include measurements of serum thyroid hormones, thyroid gland pathology and neurodevelopmental assessments, but do not directly inform on specific modes-of-action. Opportunities to address additional non-routine parameters reflecting critical events of AOPs in toxicological assessments are presented. These parameters appear relevant to support the identification of specific thyroid-related modes-of-action, provided that prevailing technical limitations are overcome. Current understanding of quantitative key event relationships is often weak, but would be needed to determine if the triggering of a molecular initiating event will ultimately result in an adverse outcome. Also, significant species differences in all processes related to thyroid hormone signalling are evident, but the biological implications thereof (including human relevance) are often unknown. In conclusion, careful consideration of the measurement (e.g. timing, method) and interpretation of additional non-routine parameters is warranted. These findings will be used in a subsequent paper to propose a testing strategy to identify if a substance may elicit maternal thyroid hormone imbalance and potentially also neurodevelopmental effects in the progeny.
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Affiliation(s)
- Sue Marty
- The Dow Chemical Company, Midland, MI, USA
| | | | | | | | | | | | | | - Ursula G Sauer
- Scientific Consultancy - Animal Welfare, Neubiberg, Germany
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Alarcón S, Esteban J, Roos R, Heikkinen P, Sánchez-Pérez I, Adamsson A, Toppari J, Koskela A, Finnilä MAJ, Tuukkanen J, Herlin M, Hamscher G, Leslie HA, Korkalainen M, Halldin K, Schrenk D, Håkansson H, Viluksela M. Endocrine, metabolic and apical effects of in utero and lactational exposure to non-dioxin-like 2,2',3,4,4',5,5'-heptachlorobiphenyl (PCB 180): A postnatal follow-up study in rats. Reprod Toxicol 2021; 102:109-127. [PMID: 33992733 DOI: 10.1016/j.reprotox.2021.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 12/19/2022]
Abstract
PCB 180 is a persistent and abundant non-dioxin-like PCB (NDL-PCB). We determined the developmental toxicity profile of ultrapure PCB 180 in developing offspring following in utero and lactational exposure with the focus on endocrine, metabolic and retinoid system alterations. Pregnant rats were given total doses of 0, 10, 30, 100, 300 or 1000 mg PCB 180/kg bw on gestational days 7-10 by oral gavage, and the offspring were sampled on postnatal days (PND) 7, 35 and 84. Decreased serum testosterone and triiodothyronine concentrations on PND 84, altered liver retinoid levels, increased liver weights and induced 7-pentoxyresorufin O-dealkylase (PROD) activity were the sensitive effects used for margin of exposure (MoE) calculations. Liver weights were increased together with induction of the metabolizing enzymes cytochrome P450 (CYP) 2B1, CYP3A1, and CYP1A1. Less sensitive effects included decreased serum estradiol and increased luteinizing hormone levels in females, decreased prostate and seminal vesicle weight and increased pituitary weight in males, increased cortical bone area and thickness of tibial diaphysis in females and decreased cortical bone mineral density in males. Developmental toxicity profiles were partly different in male and female offspring, males being more sensitive to increased liver weight, PROD induction and decreased thyroxine concentrations. MoE assessment indicated that the 95th percentile of current maternal PCB 180 concentrations do not exceed the estimated tolerable human lipid-based PCB 180 concentration. Although PCB 180 is much less potent than dioxin-like compounds, it shares several toxicological targets suggesting a potential for interactions.
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Affiliation(s)
- Sonia Alarcón
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche (Alicante), Spain; Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Javier Esteban
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche (Alicante), Spain.
| | - Robert Roos
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Päivi Heikkinen
- Environmental Health Unit, Finnish Institute for Health and Welfare (THL), P.O. Box 95, Kuopio, FI-70701, Finland
| | - Ismael Sánchez-Pérez
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche (Alicante), Spain
| | - Annika Adamsson
- Research Center for Integrative Physiology and Pharmacology and Centre for Population Health Research, Institute of Biomedicine, University of Turku, Department of Paediatrics, Turku University Hospital, Turku, FI-20520, Finland
| | - Jorma Toppari
- Research Center for Integrative Physiology and Pharmacology and Centre for Population Health Research, Institute of Biomedicine, University of Turku, Department of Paediatrics, Turku University Hospital, Turku, FI-20520, Finland
| | - Antti Koskela
- Department of Anatomy and Cell Biology, Institute of Cancer Research and Translational Medicine, University of Oulu, Oulu, Finland
| | - Mikko A J Finnilä
- Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Juha Tuukkanen
- Department of Anatomy and Cell Biology, Institute of Cancer Research and Translational Medicine, University of Oulu, Oulu, Finland
| | - Maria Herlin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Gerd Hamscher
- Institute of Food Chemistry and Food Biotechnology, Justus Liebig University, Giessen, D-35392, Germany
| | - Heather A Leslie
- Department of Environment and Health, Vrije Universiteit Amsterdam, De Boelelaan 1108, Amsterdam, NL-1081 HZ, The Netherlands
| | - Merja Korkalainen
- Environmental Health Unit, Finnish Institute for Health and Welfare (THL), P.O. Box 95, Kuopio, FI-70701, Finland
| | - Krister Halldin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Dieter Schrenk
- Food Chemistry and Toxicology, University of Kaiserslautern, Kaiserslautern, D-67663, Germany
| | - Helen Håkansson
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Matti Viluksela
- School of Pharmacy (Toxicology), Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
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Fair PA, Peden-Adams MM, Mollenhauer MAM, Bossart GD, Keil DE, White ND. Effects of an environmentally relevant PCB-mixture on immune function, clinical chemistry, and thyroid hormone levels in adult female B 6C 3F 1 mice. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2021; 84:279-297. [PMID: 33357133 DOI: 10.1080/15287394.2020.1863887] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Polychlorinated biphenyls (PCBs) have been assessed for immunotoxicity; however, humans and wildlife are exposed to multiple PCBs environmentally. Therefore, the aim of this study was to examine the effects of a complex 37 PCB congener mixture identified in blubber specific to dolphins residing in the estuarine waters of Charleston, South Carolina. Immunotoxicity was determined in adult female B6C3F1 mice by assessing lymphocyte proliferation, splenic and thymic immunophenotypes, and IgM production. Mice were exposed via oral gavage to the PCB-mixture (0, 1.8, 3.6, 7.1, or 14.3 mg/kg/day) for 28 days to yield a targeted total administered dose (TAD) 0, 50, 100, 200, or 400 mg/kg. Significant increased liver weight occurred at the highest treatment. IgM production was suppressed compared to control for all treatments. Numbers of thymic CD4+/CD8+, CD4-/CD8-, and CD4+/CD8- cells were not altered, but numbers of thymic CD4-/CD8+ cells were significantly increased in the highest treatment. Lymphocyte proliferation was not markedly affected by any treatment. The numbers of splenic CD4/CD8 T-cells or MHCII+ cells were not significantly changed. Humoral immunity using the plaque-forming cell assay for determining the specific IgM antibody-forming cell response appeared to be the most sensitive endpoint affected. As the lowest concentration tested resulted in decreased IgM production and total and free thyroxine (T4) serum levels a NOAEL was not identified. The calculated ED50 for suppression of IgM production was 2.4 mg/kg/day.
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Affiliation(s)
- Patricia A Fair
- National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health & Biomolecular Research, Charleston, SC, USA
| | - Margie M Peden-Adams
- Harry Reid Center for Environmental Studies, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Meagan A M Mollenhauer
- Molecular and Cellular Biology and Pathobiology, Medical University of South Carolina, Charleston, SC, USA
| | - Gregory D Bossart
- Animal Health, Research and Conservation, Georgia Aquarium, NW Atlanta, GA, USA
| | - Deborah E Keil
- Medical Laboratory Sciences, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Natasha D White
- National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health & Biomolecular Research, Charleston, SC, USA
- Department of Education, National Oceanic and Atmospheric Administration, Silver Spring, MD, USA
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4
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Galbán-Velázquez S, Esteban J, Çakmak G, Artacho-Cordón F, León J, Barril J, Vela-Soria F, Martin-Olmedo P, Fernandez MF, Pellín MC, Arrebola JP. Associations of persistent organic pollutants in human adipose tissue with retinoid levels and their relevance to the redox microenvironment. ENVIRONMENTAL RESEARCH 2021; 195:110764. [PMID: 33497679 PMCID: PMC8127078 DOI: 10.1016/j.envres.2021.110764] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 05/30/2023]
Abstract
Humans are exposed to a myriad of chemical substances in both occupational and environmental settings. Persistent organic pollutants (POPs) have drawn attention for their adverse effects including cancer and endocrine disruption. Herein, the objectives were 1) to describe serum and adipose tissue retinol levels, along with serum retinol binding protein 4 (RBP4) concentrations, and 2) to assess the associations of adipose tissue POP levels with these retinoid parameters, as well as their potential interaction with the previously-observed POP-related disruption of redox microenvironment. Retinol was measured in both serum and adipose tissue along with RBP4 levels in serum samples of 236 participants of the GraMo adult cohort. Associations were explored by multivariable linear regression analyses and Weighted Quantile Sum regression. Polychlorinated biphenyls (PCBs) 180, 153 and 138 were related to decreased adipose tissue retinol levels and increased serum RBP4/retinol ratio. Dicofol concentrations > limit of detection were associated with decreased retinol levels in serum and adipose tissue. Additionally, increased adipose tissue retinol levels were linked to an attenuation in previously-reported associations of adipose tissue PCB-153 with in situ superoxide dismutase activity. Our results revealed a suggestive link between retinoids, PCBs and redox microenvironment, potentially relevant for both mechanistic and public health purposes.
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Affiliation(s)
| | - Javier Esteban
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain.
| | - Gonca Çakmak
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain; Department of Toxicology, Faculty of Pharmacy, Gazi University, 06330, Ankara, Turkey
| | - Francisco Artacho-Cordón
- Department of Radiology and Physical Medicine, University of Granada, 18016, Granada, Spain; CIBER Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain
| | - Josefa León
- Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain; Unidad de Gestión Clínica de Aparato Digestivo, Hospital Universitario San Cecilio de Granada, Spain; CIBER Hepatic and Digestive Diseases (CIBEREHD), 28029, Madrid, Spain
| | - Jose Barril
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
| | | | - Piedad Martin-Olmedo
- Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain; Andalusian School of Public Health, 18011, Granada, Spain
| | - Mariana F Fernandez
- Department of Radiology and Physical Medicine, University of Granada, 18016, Granada, Spain; CIBER Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain
| | - M Cruz Pellín
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche, Elche, Spain
| | - Juan P Arrebola
- CIBER Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Instituto de Investigación Biosanitaria Ibs.GRANADA, Granada, Spain; Department of Preventive Medicine and Public Health, University of Granada, Spain
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Troisi GM, Barton SJ, Liori O, Nyman M. Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption? ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 78:513-524. [PMID: 32107597 PMCID: PMC7136188 DOI: 10.1007/s00244-020-00716-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/31/2020] [Indexed: 05/28/2023]
Abstract
Polychlorinated biphenyls (PCBs) are recognised reproductive and immune system toxicants in marine mammals mediated by endocrine-disrupting mechanisms. As with other predators, seals are exposed to elevated bioaccumulated concentrations of PCBs and other persistent organic pollutants (POPs). Cryopreserved plasma samples from adult ringed (Phoca hispida; n = 39) and grey (Halichoerus grypus; n = 38) seals, sampled between 1998 and 2002 from Baltic Sea, Svalbard, and Sable Island (Canada) were used to investigate relationships between PCB exposure and sex hormone concentrations (progesterone; P4, 17α-hydroxy progesterone; 17α-OH-P4, testosterone; T4, 17β-estradiol; E2, estrone; E3). Immunoassay methods were used for quantification of analytes due to the limited sample volumes available. PCB concentrations were found to be significantly higher in Baltic seals than other sampling locations and were classed as "Exposed" seals while Svalbard and Sable Is seal were classed "Reference" seals (sexes and species separate). Mean hormone concentrations in Exposed seal were lower than Reference seals, and this was statistically significantly for 17α-OH-P4 (both sexes and both species), E2 (ringed and grey seal females), and E3 (grey seal females). Regression analyses (PCB v hormone concentrations) for each sex and species revealed significant correlations for P4 (Sable Is. female grey seals and female ringed seals), 17α-OH-P4 (Sable Is. male grey seals and Svalbard male ringed seals), T4 (Svalbard male ringed seals), E2 (female ringed seals), and E3 (female ringed seals and Baltic female grey seals). Although significant correlations are not evidence of cause and effect, the potential impact of hormone changes on endocrine homeostasis and reproductive health for seal populations warrants further investigation given that PCB concentrations found here are in the same range as those currently reported in seals from these populations.
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Affiliation(s)
- G M Troisi
- Department of Mechanical & Aerospace Engineering and Institute for Environment, Health & Societies, College of Engineering, Design and Physical Sciences, Brunel University London, Kingston Lane, Uxbridge, UB8 3PH, UK.
| | - S J Barton
- Department of Chemical and Pharmaceutical Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey, KT1 2EE, UK
| | - O Liori
- Department of Chemical and Pharmaceutical Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey, KT1 2EE, UK
| | - M Nyman
- Finnish Game and Fisheries Research Institute, Metsähallitus, Kirjaamo, P.O. Box 94, Vantaainland, 01301, Finland
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6
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Dong H, Godlewska M, Wade MG. A rapid assay of human thyroid peroxidase activity. Toxicol In Vitro 2020; 62:104662. [DOI: 10.1016/j.tiv.2019.104662] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/12/2019] [Accepted: 09/20/2019] [Indexed: 11/25/2022]
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Gutleb AC, Cambier S, Serchi T. Impact of Endocrine Disruptors on the Thyroid Hormone System. Horm Res Paediatr 2018; 86:271-278. [PMID: 26771660 DOI: 10.1159/000443501] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/14/2015] [Indexed: 11/19/2022] Open
Abstract
The thyroid hormone (TH) system plays a central role in central physiological processes of many species, including mammals and humans, ranging from growth and cell differentiation, energy metabolism, thermoregulation and phasing of hibernation or annual movements of migratory species, metamorphosis from larvae to adult forms, brain development, reproduction, or the cardiovascular system. Several chemicals are known to be TH-disrupting compounds (THDCs) and have been shown to interact with virtually all elements of TH homeostasis such as feedback mechanisms with the hypothalamus-pituitary axis, TH synthesis, TH storage and release from the thyroid gland, transport protein binding and TH distribution in tissues and organs, cellular TH uptake, intracellular TH metabolism, and TH receptor binding. Therefore, chemicals interfering with the TH homeostasis have the potential to interact with many of these important processes, and especially early-life stage exposure results in permanent alterations of tissue organization and homeostatic regulation of adaptive processes. This is not only of theoretical importance as the reported plasma concentrations of THDCs in human plasma fall well within the range of reported in vitro effect concentrations, and this is of even higher importance as the developing fetus and young children are in a sensitive developmental stage.
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Affiliation(s)
- Arno C Gutleb
- Environmental Health Group, Life Cycle Sustainability and Risk Assessment (LiSRA) Unit, Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), Esch/Alzette, Luxembourg
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Li J, Tao Y, Chen S, Li H, Chen P, Wei MZ, Wang H, Li K, Mazzeo M, Duan Y. A flexible plasma-treated silver-nanowire electrode for organic light-emitting devices. Sci Rep 2017; 159:1-8. [PMID: 29184113 DOI: 10.1016/j.envres.2017.07.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 07/21/2017] [Accepted: 07/24/2017] [Indexed: 04/29/2023] Open
Abstract
Silver nanowires (AgNWs) are a promising candidate to replace indium tin oxide (ITO) as transparent electrode material. However, the loose contact at the junction of the AgNWs and residual surfactant polyvinylpyrrolidone (PVP) increase the sheet resistance of the AgNWs. In this paper, an argon (Ar) plasma treatment method is applied to pristine AgNWs to remove the PVP layer and enhance the contact between AgNWs. By adjusting the processing time, we obtained AgNWs with a sheet resistance of 7.2Ω/□ and a transmittance of 78% at 550 nm. To reduce the surface roughness of the AgNWs, a peel-off process was used to transfer the AgNWs to a flexible NOA63 substrate. Then, an OLED was fabricated with the plasma-treated AgNWs electrode as anode. The highest brightness (27000 cd/m2) and current efficiency (11.8 cd/A) was achieved with a 30 nm thick light emitting layer of tris-(8-hydroxyquinoline) aluminum doped with 1% 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5 H,11H-(1)-benzopyropyrano(6,7-8-I,j)quinolizin-11-one. Compared to thermal annealing, the plasma-treated AgNW film has a lower sheet resistance, a shorter processing time, and a better hole-injection. Our results indicate that plasma treatment is an effective and efficient method to enhance the conductivity of AgNW films, and the plasma-treated AgNW electrode is suitable to manufacture flexible organic optoelectronic devices.
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Affiliation(s)
- Jun Li
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
| | - Ye Tao
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
| | - Shufen Chen
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu Nation Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9Wenyuan Road, Nanjing, 210023, China
| | - Huiying Li
- College of Computer Science and Technology, Jilin University, Changchun, 130012, China
| | - Ping Chen
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
| | - Meng-Zhu Wei
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu Nation Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9Wenyuan Road, Nanjing, 210023, China
| | - Hu Wang
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
| | - Kun Li
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China
| | - Marco Mazzeo
- Istituto di Nanotecnologia, CNR-Nanotec, c/o Campus Ecotekne via Monteroni, Lecce, 73100, Italy
| | - Yu Duan
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Jilin, 130012, China.
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu Nation Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9Wenyuan Road, Nanjing, 210023, China.
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9
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Rogstad TW, Sonne C, Villanger GD, Ahlstøm Ø, Fuglei E, Muir DCG, Jørgensen E, Jenssen BM. Concentrations of vitamin A, E, thyroid and testosterone hormones in blood plasma and tissues from emaciated adult male Arctic foxes (Vulpes lagopus) dietary exposed to persistent organic pollutants (POPs). ENVIRONMENTAL RESEARCH 2017; 154:284-290. [PMID: 28119248 DOI: 10.1016/j.envres.2017.01.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 06/06/2023]
Abstract
The aim of the present study was to investigate the relationships and effects of oral POP exposure on retinol (vitamin A), α-tocopherol (vitamin E), thyroid hormones and testosterone in emaciated adult farmed Arctic foxes. Eight brother-pairs were exposed to either a diet containing naturally POP-contaminated minke whale blubber (Balaenoptera acutorostrata) (n=8), or a control diet containing pig (Sus scrofa) fat as the primary fat source (n=8) for 22 months. In the whale blubber containing feed the ∑POPs concentration was 802ng/g w.w. and it was 24ng/g w.w. in control feed. The liver mass was significantly higher and the ratio of FT4 (free thyroxine):FT3 (free triiodothyronine) was significantly lower in the POP exposed group as compared to the control group given feed with pig fat (both p<0.05). The exposed group revealed lower plasma and liver concentrations of α-tocopherol compared to the control group (both p<0.05). These results indicate that plasma FT4:FT3 ratio and plasma and liver α-tocopherol are valuable biomarker endpoints for chronic oral POP exposure in wild Arctic foxes. Based on this we suggest that plasma FT4:FT3 ratio and plasma and liver α-tocopherol are valuable biomarker endpoints for chronic POP exposure in wildlife Arctic foxes and that these perturbations may affect their health status.
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Affiliation(s)
- Tonje W Rogstad
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Christian Sonne
- Aarhus University, Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark.
| | - Gro D Villanger
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Mental and Physical Health, Department of Child Health, Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, 0473 Oslo, Norway
| | - Øystein Ahlstøm
- Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, N-1432 Ås, Norway
| | - Eva Fuglei
- Norwegian Polar Institute, FRAM Centre, NO-9296 Tromsø, Norway
| | - Derek C G Muir
- National Water Research Institute, Environment Canada, Burlington, Ontario, Canada L7R 4A6
| | - Even Jørgensen
- Department of Arctic and Marine Biology, UiT the Arctic University of Norway, N-9037 Tromsø, Norway
| | - Bjørn Munro Jenssen
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
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10
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Kezios K, Gu Y, Liu X, Cirillo P, Tarrant D, Petreas M, Park JS, Cohn B, Factor-Litvak P. Hydroxylated polychlorinated biphenyl metabolites (OH-PCBs), maternal smoking and size at birth. Reprod Toxicol 2017; 71:166-175. [PMID: 28314564 DOI: 10.1016/j.reprotox.2017.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/16/2017] [Accepted: 02/21/2017] [Indexed: 11/18/2022]
Abstract
In a sample of 442 births from the Child Health and Development Studies cohort, we examined associations between maternal prenatal exposure to hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) and pregnancy outcomes, and whether associations were mediated by maternal thyroid hormone levels and/or modified by maternal smoking. Compared to nonsmokers, smokers had twice the mean concentration of 4-OH-CB107 (p<0.001) and lower levels of its parent compound, PCB118 (p=0.001). Among mothers who smoked, the birth weight of newborns with maternal concentrations of 4-OH-CB107 in the upper quartile was 316g lighter (95% confidence interval (CI) 566, 65) compared to those with maternal concentrations in the lowest quartile, after control for PCB118 and other potential confounders. This association was not observed for non-smoking mothers and was not mediated by maternal thyroid hormone levels. Maternal prenatal 4-OH-CB107 levels appear to be influenced by maternal smoking and contribute to lower birth weight among smokers.
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Affiliation(s)
- Katrina Kezios
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Yiwei Gu
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Xinhua Liu
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Piera Cirillo
- Child Health and Development Studies, Public Health Institute, Berkeley, CA 94709, USA
| | - Darcy Tarrant
- Department of Toxic Substances Control California Environmental Protection Agency, Berkeley, CA 94710, USA
| | - Myrto Petreas
- Department of Toxic Substances Control California Environmental Protection Agency, Berkeley, CA 94710, USA
| | - Jun-Soo Park
- Department of Toxic Substances Control California Environmental Protection Agency, Berkeley, CA 94710, USA
| | - Barbara Cohn
- Child Health and Development Studies, Public Health Institute, Berkeley, CA 94709, USA
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA.
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Pauwels D, Pilehvar S, Geboes B, Hubin A, De Wael K, Breugelmans T. A new multisine-based impedimetric aptasensing platform. Electrochem commun 2016. [DOI: 10.1016/j.elecom.2016.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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12
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Mikaelian I, Labelle P, Kopal M, De Guise S, Martineau D. Adenomatous Hyperplasia of the Thyroid Gland in Beluga Whales (Delphinapterus leucas) from the St. Lawrence Estuary and Hudson Bay, Quebec, Canada. Vet Pathol 2016; 40:698-703. [PMID: 14608025 DOI: 10.1354/vp.40-6-698] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We evaluated thyroid gland lesions in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary ( n = 16) and Hudson Bay ( n = 14). Follicular cysts and nodules of adenomatous hyperplasia of the thyroid gland were found in eight and nine adults from the St. Lawrence Estuary ( n = 10), respectively, and in four and six adults from Hudson Bay ( n = 14), respectively. The total volume of the lesions of thyroid adenomatous hyperplasia was positively correlated with age in both populations. Comparison between populations could not be performed because of differences in age structures of sample groups. Beluga whales from both populations have unique thyroid lesions among marine mammals.
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Affiliation(s)
- I Mikaelian
- #98, The Jackson Laboratory, Bar Harbor, ME 04609-1500, USA.
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13
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Berntssen MHG, Ørnsrud R, Rasinger J, Søfteland L, Lock EJ, Kolås K, Moren M, Hylland K, Silva J, Johansen J, Lie K. Dietary vitamin A supplementation ameliorates the effects of poly-aromatic hydrocarbons in Atlantic salmon (Salmo salar). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 175:171-183. [PMID: 27060237 DOI: 10.1016/j.aquatox.2016.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/11/2016] [Accepted: 03/19/2016] [Indexed: 06/05/2023]
Abstract
Several studies have reported on the interaction between vitamin A (VA) and aryl hydrocarbon receptor (AhR)-binding toxicants, including poly-aromatic hydrocarbons (PAHs). In aquaculture, the use of plant oils in novel aquafeeds can increase PAH levels while simultaneously lowering natural VA background levels, causing the need to supplement plant oil-based feeds with synthetic VA. To study dietary VA-PAH interactions, Atlantic salmon (initial weight 195±0.15g) were fed four identical plant-based diets that were supplemented with PAHs (100 and 10mgkg(-1) benzo[a]pyrene (BaP) and phenanthrene (Phe), respectively) or VA (retinyl acetate 8721IUkg(-1)) separately or combined for 2.5 months in a 2×2 factorial design, with triplicate net-pens per diet. Dietary PAH significantly reduced hepatic VA storage, and VA-enriched diets restored hepatic VA. There was a significant PAH-VA interaction effect on hepatic BaP, but not Phe, accumulation, with reduced hepatic BaP concentrations in fish fed VA+PAH compared to fish fed PAH alone. Concurrently, PAH and VA significantly interacted in their effects on CYP1A phase I biotransformation as observed from increased ethoxyresorufin-O-deethylase (EROD) activity, increased CYP1A protein concentration, and elevated transcription (cyp1a1 gene expression) in fish fed PAH+VA compared to PAH alone. Dietary VA supplementation alone had no significant effect on CYP1A phase I biotransformation. Metabolomic assessment showed that dietary VA caused a restoration of metabolic intermediates involved in energy metabolism that were affected by dietary PAH. Moreover, a PAH-induced growth inhibition was partially ameliorated by dietary VA supplementation. In conclusion, dietary VA interacted with PAH toxicity on the level of CYP1A-mediated detoxification, hepatic PAH accumulation, energy allocation, and growth.
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Affiliation(s)
| | | | | | | | | | | | | | - Ketil Hylland
- University of Oslo, Department of Bioscience, N-0316 Oslo, Norway
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Koh WX, Hornbuckle KC, Marek RF, Wang K, Thorne PS. Hydroxylated polychlorinated biphenyls in human sera from adolescents and their mothers living in two U.S. Midwestern communities. CHEMOSPHERE 2016; 147:389-95. [PMID: 26774304 PMCID: PMC4747419 DOI: 10.1016/j.chemosphere.2015.12.113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 12/12/2015] [Accepted: 12/25/2015] [Indexed: 05/18/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) have been detected in human specimens and some are suspected as being more toxic than their parent compounds. We compared 58 OH-PCB congeners (in 51 chromatographic peaks) in serum samples from participants in the AESOP Study, a longitudinal cohort study of adolescents and their mothers living in urban and rural areas in the United States. We hypothesized that adolescents would have lower levels of OH-PCBs than their mothers and that serum concentration of OH-PCBs would be stable over a 3-year period. We found statistically significant differences in total OH-PCBs between age groups in both East Chicago (p = 0.001) and Columbus Junction (p < 0.001), with adolescents having lower concentrations than their mothers. We observed that lower-chlorinated OH-PCBs were rarely detected, suggesting that they are not retained in serum and/or rapidly biotransformed into other forms. Twelve OH-PCBs, including several that are rarely reported (4,4'-diOH-PCB 202, 4'-OH-PCB 208, and 4-OH-PCB 163) were detected in over 60% of participants. Lastly, from repeated measures within subject serum for three OH-PCBs, concentrations of 4-OH-PCB 107 and 4-OH-PCB 187 changed significantly over three years of the study.
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Affiliation(s)
- Wen Xin Koh
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, United States
| | - Keri C Hornbuckle
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, United States; Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, IA 52242, United States.
| | - Rachel F Marek
- Department of Civil and Environmental Engineering, The University of Iowa, Iowa City, IA 52242, United States
| | - Kai Wang
- Department of Biostatistics, The University of Iowa, Iowa City, IA 52242, United States
| | - Peter S Thorne
- Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA 52242, United States; Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA 52242, United States.
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15
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Vitamins A and E in liver, kidney, and whole blood of East Greenland polar bears sampled 1994–2008: reference values and temporal trends. Polar Biol 2015. [DOI: 10.1007/s00300-015-1830-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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16
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Shmarakov IO. Retinoid-xenobiotic interactions: the Ying and the Yang. Hepatobiliary Surg Nutr 2015; 4:243-67. [PMID: 26311625 DOI: 10.3978/j.issn.2304-3881.2015.05.05] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 05/13/2015] [Indexed: 12/20/2022]
Abstract
The literature provides compelling evidence pointing to tight metabolic interactions between retinoids and xenobiotics. These are extensive and important for understanding xenobiotic actions in the body. Within the body, retinoids affect xenobiotic metabolism and actions and conversely, xenobiotics affect retinoid metabolism and actions. This article summarizes data that establish the importance of retinoid-dependent metabolic pathways for sustaining the body's responses to xenobiotic exposure, including the roles of all-trans- and 9-cis-retinoic acid for protecting mammals from harmful xenobiotic effects and for ensuring xenobiotic elimination from the body. This review will also consider molecular mechanisms underlying xenobiotic toxicity focusing on how this may contribute to retinoid deficiency and disruption of normal retinoid homeostasis. Special attention is paid to xenobiotic molecular targets (nuclear receptors, regulatory proteins, enzymes, and transporters) which affect retinoid metabolism and signaling.
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Affiliation(s)
- Igor O Shmarakov
- Department of Biochemistry and Biotechnology, Chernivtsi National University, Chernivtsi, Ukraine
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17
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Murk AJ, Rijntjes E, Blaauboer BJ, Clewell R, Crofton KM, Dingemans MML, Furlow JD, Kavlock R, Köhrle J, Opitz R, Traas T, Visser TJ, Xia M, Gutleb AC. Mechanism-based testing strategy using in vitro approaches for identification of thyroid hormone disrupting chemicals. Toxicol In Vitro 2013; 27:1320-46. [PMID: 23453986 DOI: 10.1016/j.tiv.2013.02.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 02/07/2013] [Accepted: 02/18/2013] [Indexed: 11/16/2022]
Abstract
The thyroid hormone (TH) system is involved in several important physiological processes, including regulation of energy metabolism, growth and differentiation, development and maintenance of brain function, thermo-regulation, osmo-regulation, and axis of regulation of other endocrine systems, sexual behaviour and fertility and cardiovascular function. Therefore, concern about TH disruption (THD) has resulted in strategies being developed to identify THD chemicals (THDCs). Information on potential of chemicals causing THD is typically derived from animal studies. For the majority of chemicals, however, this information is either limited or unavailable. It is also unlikely that animal experiments will be performed for all THD relevant chemicals in the near future for ethical, financial and practical reasons. In addition, typical animal experiments often do not provide information on the mechanism of action of THDC, making it harder to extrapolate results across species. Relevant effects may not be identified in animal studies when the effects are delayed, life stage specific, not assessed by the experimental paradigm (e.g., behaviour) or only occur when an organism has to adapt to environmental factors by modulating TH levels. Therefore, in vitro and in silico alternatives to identify THDC and quantify their potency are needed. THDC have many potential mechanisms of action, including altered hormone production, transport, metabolism, receptor activation and disruption of several feed-back mechanisms. In vitro assays are available for many of these endpoints, and the application of modern '-omics' technologies, applicable for in vivo studies can help to reveal relevant and possibly new endpoints for inclusion in a targeted THDC in vitro test battery. Within the framework of the ASAT initiative (Assuring Safety without Animal Testing), an international group consisting of experts in the areas of thyroid endocrinology, toxicology of endocrine disruption, neurotoxicology, high-throughput screening, computational biology, and regulatory affairs has reviewed the state of science for (1) known mechanisms for THD plus examples of THDC; (2) in vitro THD tests currently available or under development related to these mechanisms; and (3) in silico methods for estimating the blood levels of THDC. Based on this scientific review, the panel has recommended a battery of test methods to be able to classify chemicals as of less or high concern for further hazard and risk assessment for THD. In addition, research gaps and needs are identified to be able to optimize and validate the targeted THD in vitro test battery for a mechanism-based strategy for a decision to opt out or to proceed with further testing for THD.
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Affiliation(s)
- AlberTinka J Murk
- Wageningen University, Sub-department of Toxicology, Tuinlaan 5, 6703 HE Wageningen, The Netherlands.
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18
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Bytingsvik J, Lie E, Aars J, Derocher AE, Wiig Ø, Jenssen BM. PCBs and OH-PCBs in polar bear mother-cub pairs: a comparative study based on plasma levels in 1998 and 2008. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 417-418:117-128. [PMID: 22264925 DOI: 10.1016/j.scitotenv.2011.12.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 05/31/2023]
Abstract
The aim of this study was to examine the plasma concentrations and prevalence of polychlorinated biphenyls (PCBs) and hydroxylated PCB-metabolites (OH-PCBs) in polar bear (Ursus maritimus) mothers (n=26) and their 4 months old cubs-of-the-year (n=38) from Svalbard to gain insight into the mother-cub transfer, biotransformation and to evaluate the health risk associated with the exposure to these contaminants. As samplings were performed in 1997/1998 and 2008, we further investigated the differences in levels and pattern of PCBs between the two sampling years. The plasma concentrations of Σ(21)PCBs (1997/1998: 5710 ± 3090 ng/g lipid weight [lw], 2008: 2560 ± 1500 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 228 ± 60 ng/g wet weight [ww], 2008: 80 ± 38 ng/g ww) in mothers were significantly lower in 2008 compared to in 1997/1998. In cubs, the plasma concentrations of Σ(21)PCBs (1997/1998: 14680 ± 5350 ng/g lw, 2008: 6070 ± 2590 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 98 ± 23 ng/g ww, 2008: 49 ± 21 ng/g ww) were also significantly lower in 2008 than in 1997/1998. Σ(21)PCBs in cubs was 2.7 ± 0.7 times higher than in their mothers. This is due to a significant maternal transfer of these contaminants. In contrast, Σ(6)OH-PCBs in cubs were approximately 0.53 ± 0.16 times the concentration in their mothers. This indicates a lower maternal transfer of OH-PCBs compared to PCBs. The majority of the metabolite/precursor-ratios were lower in cubs compared to mothers. This may indicate that cubs have a lower endogenous capacity to biotransform PCBs to OH-PCBs than polar bear mothers. Exposure to PCBs and OH-PCBs is a potential health risk for polar bears, and the levels of PCBs and OH-PCBs in cubs from 2008 were still above levels associated with health effects in humans and wildlife.
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Affiliation(s)
- Jenny Bytingsvik
- Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway.
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Braune BM, Trudeau S, Jeffrey DA, Mallory ML. Biomarker responses associated with halogenated organic contaminants in northern fulmars (Fulmarus glacialis) breeding in the Canadian Arctic. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2011; 159:2891-2898. [PMID: 21571413 DOI: 10.1016/j.envpol.2011.04.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 04/20/2011] [Accepted: 04/22/2011] [Indexed: 05/30/2023]
Abstract
We examined relationships between hepatic concentrations of halogenated organic contaminants and ethoxyresorufin O-deethylase (EROD) activity and retinoid (vitamin A) concentrations in livers, as well as retinol and thyroid hormone (TT(3), TT(4)) levels in blood plasma, of northern fulmars at two breeding colonies in the Canadian High Arctic. Biomarker levels or responses did not differ significantly between males and females at either colony, nor was there any significant difference between colonies. No significant relationships were found between thyroid hormone or hepatic retinoid concentrations and any of the dioxin-like compounds or their Toxic Equivalents (TEQs) although significant positive correlations were found with plasma retinol (p < 0.03). EROD activity was significantly correlated with hepatic dioxin-like compounds and their TEQs (p < 0.001) as well as total PCBs (p < 0.01), which suggests that EROD induction occurs in northern fulmars at environmentally-relevant concentrations.
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Affiliation(s)
- Birgit M Braune
- Environment Canada, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, Ontario, Canada K1A 0H3.
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20
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Gabrielsen KM, Villanger GD, Lie E, Karimi M, Lydersen C, Kovacs KM, Jenssen BM. Levels and patterns of hydroxylated polychlorinated biphenyls (OH-PCBs) and their associations with thyroid hormones in hooded seal (Cystophora cristata) mother-pup pairs. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 105:482-491. [PMID: 21888873 DOI: 10.1016/j.aquatox.2011.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/04/2011] [Accepted: 08/06/2011] [Indexed: 05/31/2023]
Abstract
Blood (plasma/serum) samples from 14 adult female and their pups (1-4 days old) captured in the West Ice, east of Greenland were analysed for concentrations of total and free thyroxine and triiodothyronine (TT4, FT4, TT3, FT3), and hydroxylated polychlorinated biphenyls (OH-PCBs). The levels of all thyroid hormones (THs) were significantly higher in pups than in mothers. Sum OH-PCB levels (ΣOH-PCBs: 4-OH-CB107, 3'-OH-CB138, 4-OH-CB146, 4'-OH-CB172, 4-OH-CB187) were significantly higher in mothers (3.98 ± 1.55 pmol/g; 1.40 ± 0.54 ng/g wet weight) as compared to pups (1.95 ± 0.78 pmol/g; 0.68 ± 0.28 ng/g wet weight). Plasma levels of TT4 and FT4 in mothers increased as a function of pup age, as did levels of individual OH-PCBs in both mothers and pups. The pattern of OH-PCBs in the pups was similar to their mothers. We suggest that OH-PCBs found in pups are transferred from their mothers during gestation and that the transfer also continues after parturition via milk. Principal component analysis (PCA) showed that in pups, 4-OH-CB107 and 3'-OH-CB138 were negatively associated with FT4:FT3 and TT3:FT3 ratios, respectively. These relationships were confirmed by partial correlation analysis correcting for pup age. PCA suggested that 4'-OH-CB172 and 4-OH-CB187 were negatively associated with TT3 in mothers. However, this was not confirmed by correlation tests. Although statistical relationships should be interpreted with caution, the study indicates that young developing seals are more sensitive compared to adults with respect to TH-related effects of OH-PCBs.
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21
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Ishihara A, Makita Y, Yamauchi K. Gene expression profiling to examine the thyroid hormone-disrupting activity of hydroxylated polychlorinated biphenyls in metamorphosing amphibian tadpole. J Biochem Mol Toxicol 2011; 25:303-11. [DOI: 10.1002/jbt.20390] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 01/27/2011] [Accepted: 02/16/2011] [Indexed: 11/10/2022]
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22
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Kirkegaard M, Sonne C, Dietz R, Letcher RJ, Jensen AL, Hansen SS, Jenssen BM, Grandjean P. Alterations in thyroid hormone status in Greenland sledge dogs exposed to whale blubber contaminated with organohalogen compounds. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:157-163. [PMID: 20888641 DOI: 10.1016/j.ecoenv.2010.08.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 08/27/2010] [Accepted: 08/28/2010] [Indexed: 05/29/2023]
Abstract
As a model of high trophic level carnivores, sledge dogs were fed from 2 to 18 months of age with minke whale blubber containing organohalogen compounds (OHC) corresponding to 128 μg PCB/day. Controls were fed uncontaminated porcine fat. Thyroid hormone levels were assessed in 7 exposed and 7 control sister bitches (sampled at age 6-18 months) and 4 exposed and 4 control pups, fed the same diet as their mothers (sampled age 3-12 months). Lower free and total T3 and T4 were seen in exposed vs. control bitches beyond 10 months of age, and total T3 was lower through 3-12 months of age in exposed pups. A negative correlation with thyroid gland weight was significant for ΣDDT, as was a positive association with total T3 for dieldrin. This study therefore supports observational data that OHCs may adversely affect thyroid functions, and it suggests that OHC exposure duration of 10 months or more may be required for current OHC contamination levels to result in detectable adverse effects on thyroid hormone dynamics.
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Affiliation(s)
- Maja Kirkegaard
- Department of Environmental Medicine, Institute of Public Health, University of Southern Denmark, J.B.Winsløvsvej 17, DK-5000 Odense, Denmark.
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23
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Helgason LB, Verreault J, Braune BM, Borgå K, Primicerio R, Jenssen BM, Gabrielsen GW. Relationship between persistent halogenated organic contaminants and TCDD-toxic equivalents on EROD activity and retinoid and thyroid hormone status in northern fulmars. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:6117-6123. [PMID: 20888620 DOI: 10.1016/j.scitotenv.2010.08.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 05/29/2023]
Abstract
We investigated whether the hepatic cytochrome P450 1A activity (measured as 7-ethoxyresorufin-O-deethylase (EROD)) and plasma thyroid hormone and liver retinoid concentrations were explained by liver and blood levels of halogenated organic contaminants (HOCs) in free-ranging breeding northern fulmars (Fulmarus glacialis) from Bjørnøya in the Norwegian Arctic. Hepatic EROD activity and liver levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were positively correlated, suggesting that hepatic EROD activity is a good indicator for dioxin and dioxin-like HOC exposure in breeding northern fulmars. There were not found other strong relationships between HOC concentrations and hepatic EROD activity, plasma thyroid or liver retinoid concentrations in the breeding northern fulmars. It is suggested that the HOC levels found in the breeding northern fulmars sampled on Bjørnøya were too low to affect plasma concentrations of thyroid hormones and liver levels of retinol and retinyl palmitate, and that hepatic EROD activity is a poor indicator of polychlorinated biphenyl (PCB) and pesticide exposure.
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Affiliation(s)
- Lisa B Helgason
- Norwegian Polar Institute, Polar Environmental Centre, N-9296 Tromsø, Norway.
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Sonne C. Health effects from long-range transported contaminants in Arctic top predators: An integrated review based on studies of polar bears and relevant model species. ENVIRONMENT INTERNATIONAL 2010; 36:461-491. [PMID: 20398940 DOI: 10.1016/j.envint.2010.03.002] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 03/06/2010] [Accepted: 03/10/2010] [Indexed: 05/29/2023]
Abstract
The aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (OCs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs) and mercury (Hg) on polar bear (Ursus maritimus) health. Multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do not represent true cause-and-effects. Therefore, information from controlled studies of farmed Norwegian Arctic foxes (Vulpes lagopus) and housed East and West Greenland sledge dogs (Canis familiaris) were included as supportive weight of evidence in the clarification of contaminant exposure and health effects in polar bears. The review showed that hormone and vitamin concentrations, liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be influenced by contaminant exposure. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. The range of tissue concentration, at which these alterations were observed in polar bears, were ca. 1-70,000 ng/g lw for OCs (blood plasma concentrations of some PCB metabolites even higher), ca. 1-1000 ng/g lw for PBDEs and for PFCs and Hg 114-3052 ng/g ww and 0.1-50 microg/g ww, respectively. Similar concentrations were found in farmed foxes and housed sledge dogs while the lack of dose response designs did not allow an estimation of threshold levels for oral exposure and accumulated tissue concentrations. Nor was it possible to pinpoint a specific group of contaminants being more important than others nor analyze their interactions. For East Greenland polar bears the corresponding daily SigmaOC and SigmaPBDE oral exposure was estimated to be 35 and 0.34 microg/kg body weight, respectively. Furthermore, PFC concentrations, at which population effect levels could occur, are likely to be reached around year 2012 for the East Greenland polar bear subpopulation if current increasing temporal trends continue. Such proposed reproductive population effects were supported by physiological based pharmacokinetic (PBPK) modelling of critical body residues (CBR) with risk quotients >or=1 for SigmaPCB, dieldrin, SigmaPFC and SigmaOHC (organohalogen contaminant). The estimated daily TEQ for East Greenland polar bears and East Greenland sledge dogs were 32-281-folds above WHO SigmaTEQ guidelines for humans. Compared to human tolerable daily intake (TDI), these were exceeded for PCBs, dieldrin, chlordanes and SigmaHCH in East Greenland polar bears. Comparisons like these should be done with caution, but together with the CBR modelling and T-score estimations, these were the only available tools for polar bear risk evaluation. In conclusion, polar bears seem to be susceptible to contaminant induced stress that may have an overall sub-clinical impact on their health and population status via impacts on their immune and reproductive systems.
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Affiliation(s)
- Christian Sonne
- Section for Contaminants, Effects and Marine Mammals, Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, DK-4000 Roskilde, Denmark.
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25
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Nomiyama K, Yonehara T, Yonemura S, Yamamoto M, Koriyama C, Akiba S, Shinohara R, Koga M. Determination and characterization of hydroxylated polychlorinated biphenyls (OH-PCBs) in serum and adipose tissue of Japanese women diagnosed with breast cancer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:2890-6. [PMID: 20384381 DOI: 10.1021/es9012432] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In the present study, we analyze and characterize the levels of PCBs and OH-PCBs in serum and breast adipose tissue, and measure TH (total 3,5,5'-triiodothyronine (tT3) and total l-thyroxine (tT4)) levels in serum of Japanese women diagnosed with breast cancer (n = 51) to know how PCBs affect thyroid hormone homeostasis. Concentrations of Sigma(90)OH-PCBs in serum and adipose tissues were 630 pg g(-1) serum wet wt. and 140 pg/ g(-1) lipid wt., respectively, and the levels of OH-PCBs in adipose tissues were 4-5 times lower than in serum. The tT3 and tT4 concentrations in serum (n = 20) were 1.3 ng g(-1) serum wet wt. and 62 ng g(-1) serum wet wt., respectively. Among all the OH-PCBs, 4'-OH-CB101/120, 4-OH-CB107/4'-OH-CB108, 3'-OH-CB138, 4-OH-CB146, 3-OH-CB153, 4'-OH-CB172, and 4-OH-CB187 were the dominant isomers in serum. No significant correlation between the concentrations of the TH and OH-PCBs in serum was observed (p > 0.05). The results indicated that the relationship between the OH-PCB levels and the thyroid hormone markers was rare. From analysis of two kinds of human biological samples, it was estimated that OH-PCBs have little effect on thyroid hormone homeostasis.
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Affiliation(s)
- Kei Nomiyama
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Center for Marine Environmental Studies (CMES), Ehime University, Japan
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Kirkegaard M, Sonne C, Jakobsen J, Jenssen BM, Letcher RJ, Dietz R. Organohalogens in a whale-blubber-supplemented diet affects hepatic retinol and renal tocopherol concentrations in greenland sled dogs (Canis familiaris). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:773-786. [PMID: 20391120 DOI: 10.1080/15287391003689192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The aim of this study was to examine the plasma, liver, and kidney status of vitamin A (retinol) and vitamin E (alpha-tocopherol) in two groups of Greenland sled dogs (Canis familiaris), with a total number of 16 bitches and 8 pups. The dogs were fed either minke whale (Balaenoptera acuterostrata) blubber (exposed dogs) or uncontaminated (control group) porcine fat for up to 12 to 21 mo of age. The daily intake of 50-200 g whale blubber (mean: 112 g) constituted between 10.4 and 11.7 microg/kg body weight summation operatororganohalogen contaminants (OHC) (or between 4.6 and 6.1 microg/kg body weight summation operatorpolychlorinated biphenyls [PCB]). Retinol was approximately 18% and alpha-tocopherol 22% higher in the diet of the exposed dogs compared to controls. In adipose tissue, mean of SigmaOHC was 92 ng/g lipid weight (lw) and 5005 ng/g lw for all control (n = 12) and exposed dogs (n = 10), respectively. Hepatic retinol correlated negatively with Sigma-dichlorodiphenyldichloroethane (SigmaDDT) and and Sigma-polybrominated diphenyl ethers (SigmaPBDE) for all exposed animals. A negative correlation between kidney alpha-tocopherol and SigmaPCB concentrations was observed, whereas two positive significant correlations were observed between kidney retinol and Sigma-chlordane-related compounds (SigmaCHL) and dieldrin concentrations. Hepatic alpha-tocopherol concentrations were significantly lower in exposed compared to controls, most likely due to a combination by OHC exposure and high dietary intake of unsaturated fatty acids. These results suggest that dietary exposure from OHC may, even at low concentrations, possibly affect retinol and alpha-tocopherol status in Arctic top predators.
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Affiliation(s)
- Maja Kirkegaard
- Research Unit of Environmental Medicine, University of Southern Denmark, Odense, Denmark.
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Dreiem A, Rykken S, Lehmler HJ, Robertson LW, Fonnum F. Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells. Toxicol Appl Pharmacol 2009; 240:306-13. [PMID: 19631230 PMCID: PMC2753730 DOI: 10.1016/j.taap.2009.07.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 07/15/2009] [Accepted: 07/15/2009] [Indexed: 11/20/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14<4-OH PCB 36<4-OH PCB 34<4'-OH PCB 36<4'-OH PCB 68<4-OH PCB 39<4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.
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Affiliation(s)
- Anne Dreiem
- Department of Biochemistry, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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Okada K, Hashimoto S, Funae Y, Imaoka S. Hydroxylated Polychlorinated Biphenyls (PCBs) Interact with Protein Disulfide Isomerase and Inhibit Its Activity. Chem Res Toxicol 2009; 22:899-904. [DOI: 10.1021/tx800476j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kazushi Okada
- Nanobiotechnology Research Center and Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan, and Department of Chemical Biology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Shoko Hashimoto
- Nanobiotechnology Research Center and Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan, and Department of Chemical Biology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Yoshihiko Funae
- Nanobiotechnology Research Center and Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan, and Department of Chemical Biology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
| | - Susumu Imaoka
- Nanobiotechnology Research Center and Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan, and Department of Chemical Biology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan
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Routti H, Letcher RJ, Arukwe A, Van Bavel B, Yoccoz NG, Chu S, Gabrielsen GW. Biotransformation of PCBs in relation to phase I and II xenobiotic-metabolizing enzyme activities in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:8952-8. [PMID: 19192824 DOI: 10.1021/es801682f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Polychlorinated biphenyls (PCBs) may induce activity of hepatic enzymes, mainly Phase I monooxygenases and conjugating Phase II enzymes, that catalyze the metabolism of PCBs leading to formation of metabolites and to potential adverse health effects. The present study investigates the concentration and pattern of PCBs, the induction of hepatic phase I and II enzymes, and the formation of hydroxy (OH) and methylsulfonyl (CH3SO2=MeSO2) PCB metabolites in two ringed seal (Phoca hispida) populations, which are contrasted by the degree of contamination exposure, that is, highly contaminated Baltic Sea (n=31) and less contaminated Svalbard (n=21). Phase I enzymes were measured as ethoxyresorufin-O-deethylation (EROD), benzyloxyresorufin-O-dealkylation (BROD), methoxyresorufin-O-demethylation (MROD), and pentoxyresorufin-O-dealkylation (PROD) activities, and phase II enzymes were measured as uridine diphosphophate glucuronosyl transferase (UDPGT) and glutathione-S-transferase (GST). Geographical comparison, multivariate, and correlation analysis indicated that sigma-PCB had a positive impact on Phase I enzyme and GST activities leading to biotransformation of group III (vicinal ortho-meta-H atoms and < or =1 ortho-chlorine (Cl)) and IV PCBs (vicinal meta-para-H atoms and < or =2 ortho-Cl). The potential precursors for the main OH-PCBs detected in plasma in the Baltic seals were group III PCBs. MeSO2-PCBs detected in liver were mainly products of group IV PCB metabolism. Both CYP1A- and CYP2B-like enzymes are suggested to be involved in the PCB biotransformation in ringed seals.
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Affiliation(s)
- Heli Routti
- Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromsø, Norway.
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Zoeller RT, Tyl RW, Tan SW. Current and Potential Rodent Screens and Tests for Thyroid Toxicants. Crit Rev Toxicol 2008; 37:55-95. [PMID: 17364705 DOI: 10.1080/10408440601123461] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This article reviews current rodent screens and tests to detect thyroid toxicants. Many points of disruption for thyroid toxicants are outlined and include: (a) changes in serum hormone level; (b) thyroperoxidase inhibitors; (c) the perchlorate discharge test; (d) inhibitors of iodide uptake; (e) effects on iodothyronine deiodinases; (f) effects on thyroid hormone action; and (g) role of binding proteins (e.g., rodent transthyretin). The major thyroid endpoints currently utilized in existing in vivo assay protocols of the Organization for Economic Cooperation and Development (OECD), Japanese researchers, and U.S. Environmental Protection Agency (EPA) include thyroid gland weight, histopathology, circulating thyroid hormone measurements, and circulating thyroid-stimulating hormone (TSH). These endpoints can be added into the existing in vivo assays for reproduction, development, and neurodevelopment that are outlined in this chapter. Strategic endpoints for possible addition to existing protocols to detect effects on developmental and adult thyroid endpoints are discussed. Many of these endpoints for detecting thyroid system disruption require development and additional research before they can be considered in existing assays. Examples of these endpoints under development include computer-assisted morphometry of the brain and evaluation of treatment-related changes in gene expression, thyrotropin-releasing hormone (TRH) and TSH challenge tests, and tests to evaluate thyroid hormone (TH)-dependent developmental events, especially in the rodent brain (e.g., measures of cerebellar and cortical proliferation, differentiation, migration, apoptosis, planimetric measures and gene expression, and oligodendrocyte differentiation). Finally, TH-responsive genes and proteins as well as enzyme activities are being explored. Existing in vitro tests are also reviewed, for example, thyroid hormone (TH) metabolism, receptor binding, and receptor activation assays, and their restrictions are described. The in vivo assays are currently the most appropriate for understanding the potential effects of a thyroid toxicant on the thyroid system. The benefits and potential limitations of the current in vivo assays are listed, and a discussion of the rodent thyroid system in the context of human health is touched upon. Finally, the importance of understanding the relationship between timing of exposure, duration of dose, and time of acquisition of the endpoints in interpreting the results of the in vivo assays is emphasized.
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Affiliation(s)
- R Thomas Zoeller
- Biology Department, Morrill Science Center, University of Massachusetts-Amherst, Amherst, Massachusetts 01003, USA.
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McNabb FMA. The Hypothalamic-Pituitary-Thyroid (HPT) Axis in Birds and Its Role in Bird Development and Reproduction. Crit Rev Toxicol 2008; 37:163-93. [PMID: 17364708 DOI: 10.1080/10408440601123552] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This article reviews thyroid function and its hypothalamic-pituitary-thyroid (HPT) axis control in birds with emphasis on the similarities and differences in thyroid function compared to mammals and other vertebrate classes. Thyroid hormones are important in metabolism and the thermogenesis required for homeothermy in birds, as in mammals, the other homeothermic class of vertebrates. Thyroid hormones play important roles in development and growth in birds, as is the case for all vertebrate classes. The developmental effects of thyroid hormones in birds are presented in the context of differences in precocial and altricial patterns of development and growth with emphasis on oviparous development. The sections on thyroid hormone actions include discussion of effects on the development of a number of tissue types as well as on seasonal organismal processes and interactions of the thyroid axis with reproduction. The current picture of how environmental chemicals may disrupt avian thyroid function is relatively limited and is presented in the context of the assessment endpoints that have been used to date. These endpoints are categorized as thyroid and HPT axis endpoints versus target organ endpoints. The final section discusses two recommended assay protocols, the avian two-generation toxicity assay and the avian one-generation assay, and whether these protocols can evaluate thyroid disruption in birds.
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Affiliation(s)
- F M Anne McNabb
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia 24061-0406, USA.
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Miyazaki W, Iwasaki T, Takeshita A, Tohyama C, Koibuchi N. Identification of the functional domain of thyroid hormone receptor responsible for polychlorinated biphenyl-mediated suppression of its action in vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 2008; 116:1231-6. [PMID: 18795168 PMCID: PMC2535627 DOI: 10.1289/ehp.11176] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2007] [Accepted: 05/13/2008] [Indexed: 05/03/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins, and poly-chlorinated dibenzofurans adversely affect the health of humans and various animals. Such effects might be partially exerted through the thyroid hormone (TH) system. We previously reported that one of the hydroxylated PCB congeners suppresses TH receptor (TR)-mediated transcription by dissociating TR from the TH response element (TRE). However, the binding site of PCB within TR has not yet been identified. OBJECTIVES We aimed to identify the functional TR domain responsible for the PCB-mediated suppression of TR action by comparing the magnitude of suppression using several representative PCB/dioxin congeners. MATERIALS AND METHODS We generated chimeric receptors by combining TR and glucocorticoid receptor (GR) and determined receptor-mediated transcription using transient transfection-based reporter gene assays, and TR-TRE binding using electrophoretic mobility shift assays. RESULTS Although several PCB congeners, including the hydroxylated forms, suppressed TR-mediated transcription to various degrees, 2,3,7,8-tetrachlorodibenzo-p-dioxin did not alter TR action, but 2,3,4,7,8-pentachlorodibenzofuran weakly suppressed it. The magnitude of suppression correlated with that of TR-TRE dissociation. The suppression by PCB congeners was evident from experiments using chimeric receptors containing a TR DNA-binding domain (DBD) but not a GR-DBD. CONCLUSIONS Several nondioxin-like PCB congeners and hydroxylated PCB compounds suppress TR action by dissociating TR from TRE through interaction with TR-DBD.
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Affiliation(s)
- Wataru Miyazaki
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Toshiharu Iwasaki
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
- Address correspondence to T. Iwasaki, Department of Integrative Physiology, Division of Biological Regulation, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan. Telephone: 81-27-220-7923. Fax: 81-27-220-7926. E-mail:
| | - Akira Takeshita
- Endocrine Center, Toranomon Hospital and Okinaka Memorial Institute for Medical Research, Tokyo, Japan
| | - Chiharu Tohyama
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Noriyuki Koibuchi
- Department of Integrative Physiology, Gunma University Graduate School of Medicine, Maebashi, Japan
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Novák J, Benísek M, Hilscherová K. Disruption of retinoid transport, metabolism and signaling by environmental pollutants. ENVIRONMENT INTERNATIONAL 2008; 34:898-913. [PMID: 18282601 DOI: 10.1016/j.envint.2007.12.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 12/11/2007] [Accepted: 12/28/2007] [Indexed: 05/25/2023]
Abstract
Although the assessment of circulatory levels of retinoids has become a widely used biomarker of exposure to environmental pollutants, the adverse effects caused by imbalance of the retinoid metabolism and signaling in wildlife are not known in detail. Retinoids play an important role in controlling such vital processes as morphogenesis, development, reproduction or apoptosis. Unlike other signaling molecules, retinoids are not strictly endogenous but they are derived from dietary sources of vitamin A or its precursors and thus they are sometimes referred to as 'dietary' hormones. Some environmental pollutants that affect embryogenesis, immunity or epithelial functions were also shown to interfere with retinoid metabolism and signaling in animals. This suggests that at least some of their toxic effects may be related to interaction with the retinoid metabolism, transport or signal transduction. This review summarizes in vivo and in vitro studies on interaction of environmental complex samples, pesticides, polychlorinated dioxins, polychlorinated biphenyls, polycyclic aromatic compounds and other organic pollutants with physiology of retinoids. It sums up contemporary knowledge about levels of interaction and mechanisms of action of the environmental contaminants.
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Affiliation(s)
- Jirí Novák
- Research Centre for Environmental Chemistry and Ecotoxicology, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic
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Phillips KP, Foster WG, Leiss W, Sahni V, Karyakina N, Turner MC, Kacew S, Krewski D. Assessing and managing risks arising from exposure to endocrine-active chemicals. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2008; 11:351-372. [PMID: 18368561 DOI: 10.1080/10937400701876657] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Managing risks to human health and the environment produced by endocrine-active chemicals (EAC) is dependent on sound principles of risk assessment and risk management, which need to be adapted to address the uncertainties in the state of the science of EAC. Quantifying EAC hazard identification, mechanisms of action, and dose-response curves is complicated by a range of chemical structure/toxicology classes, receptors and receptor subtypes, and nonlinear dose-response curves with low-dose effects. Advances in risk science including toxicogenomics and quantitative structure-activity relationships (QSAR) along with a return to the biological process of hormesis are proposed to complement existing risk assessment strategies, including that of the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC 1998). EAC represents a policy issue that has captured the public's fears and concerns about environmental health. This overview describes the process of EAC risk assessment and risk management in the context of traditional risk management frameworks, with emphasis on the National Research Council Framework (1983), taking into consideration the strategies for EAC management in Canada, the United States, and the European Union.
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Affiliation(s)
- Karen P Phillips
- Faculty of Health Sciences, University of Ottawa, Ontario, Canada.
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Suzuki G, Takigami H, Watanabe M, Takahashi S, Nose K, Asari M, Sakai SI. Identification of brominated and chlorinated phenols as potential thyroid-disrupting compounds in indoor dusts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:1794-1800. [PMID: 18441837 DOI: 10.1021/es7021895] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Our previous study demonstrated that compounds in indoor dusts strongly inhibit thyroxine (T4) binding to the human thyroid hormone transport protein transthyretin (TTR) in vitro. Exposure assessment indicated that house dust is an important medium of exposure of children to TTR-binding compounds when binding potency and dust ingestion rates are high. Here, we used chemical fractionation with in vitro competitive human TTR-binding assay and GC-MS to analyze the TTR-binding compounds in a sulfuric-acid-treated dust extract. 2,4,6-Tribromophenol (TriBPh) and 2,3,4,5,6-pentachlorophenol (PeCPh) were potent TTR-binding compounds in all dust samples. 2,4,6-TriBPh- and 2,3,4,5,6-PeCPh-derived theoretical T4 equivalents (T4EQs), calculated arithmetically from the concentrations and relative potencies, accounted for about 40-70% of experimental T4EQs detected in indoor dusts, indicating that these compounds contributed strongly to the TTR-binding potency of indoor dust. Indoor sources of 2,4,6-TriBPh might be brominated flame retardants currently used in household materials such as electrical appliances. In contrast, the 2,3,4,5,6-PeCPh might be trace evidence of past use in agricultural chemicals and preservatives in indoor or outdoor environments, because its use has been banned since 1990 in Japan. 2,4,6-TriBPh and 2,3,4,5,6-PeCPh are ubiquitous potential thyroid-disrupting compounds in the home and work environments of Japan and other countries.
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Affiliation(s)
- Go Suzuki
- Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, Tsukuba 305-8506, Japan.
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Zhang Y, Guo GL, Han X, Zhu C, Kilfoy BA, Zhu Y, Boyle P, Zheng T. Do Polybrominated Diphenyl Ethers (PBDEs) Increase the Risk of Thyroid Cancer? ACTA ACUST UNITED AC 2008; 1:195-199. [PMID: 19122824 DOI: 10.1016/j.bihy.2008.06.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
An increased incidence of thyroid cancer has been reported in many parts of the world including the United States during the past several decades. Recently emerging evidence has demonstrated that polyhalogenated aromatic hydrocarbons (PHAHs), particularly polybrominated diphenyl ethers (PBDEs), alter thyroid hormone homeostasis and cause thyroid dysfunction. However, few studies have been conducted to test whether exposure to PBDEs and other PHAHs increases the risk of thyroid cancer. Here, we hypothesize that elevated exposure to PHAHs, particularly PBDEs, increases the risk of thyroid cancer and may explain part of the increase in incidence of thyroid cancer during the past several decades. In addition, genetic and epigenetic variations in metabolic pathway genes may alter the expression and function of metabolic enzymes which are involved in the metabolism of endogenous thyroid hormones and the detoxification of PBDEs and other PHAHs. Such variation may result in different individual susceptibilities to PBDEs and other PHAHs and the subsequent development of thyroid cancer. The investigation of this hypothesis will lead to an improved understanding of the role of PBDEs and other PHAHs in thyroid tumorigenesis and may provide a real means to prevent this deadly disease.
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Affiliation(s)
- Yawei Zhang
- School of Epidemiology and Public Health, Yale University, New Haven, CT 06520, USA
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Morgado I, Hamers T, Van der Ven L, Power DM. Disruption of thyroid hormone binding to sea bream recombinant transthyretin by ioxinyl and polybrominated diphenyl ethers. CHEMOSPHERE 2007; 69:155-63. [PMID: 17553549 DOI: 10.1016/j.chemosphere.2007.04.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Revised: 02/09/2007] [Accepted: 04/04/2007] [Indexed: 05/15/2023]
Abstract
A number of chemicals released into the environment share structural similarity to the thyroid hormones (THs), thyroxine (T(4)) and triiodothyronine (T(3)) and it is thought that they may interfere with the thyroid axis and behave as endocrine disruptors (EDs). One of the ways by which such environmental contaminants may disrupt the TH axis is by binding to TH transporter proteins. Transthyretin (TTR) is one of the thyroid hormone binding proteins responsible for TH transport in the blood. TTR forms a stable tetramer that binds both T(4) and T(3) and in fish it is principally synthesized in the liver but is also produced by the brain and intestine. In the present study, we investigate the ability of some chemicals arising from pharmaceutical, industrial or agricultural production and classified as EDs, to compete with [I(125)]-T(3) for sea bream recombinant TTR (sbrTTR). Ioxinyl, a common herbicide and several polybrominated diphenyl ethers were strong inhibitors of [I(125)]-T(3) binding to TTR and some showed even greater affinity than the natural ligand T(3). The TTR competitive binding assay developed offers a quick and effective tool for preliminary risk assessment of chemicals which may disrupt the thyroid axis in teleost fish inhabiting vulnerable aquatic environments.
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Affiliation(s)
- Isabel Morgado
- Centro de Ciências do Mar, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
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McLanahan ED, Campbell JL, Ferguson DC, Harmon B, Hedge JM, Crofton KM, Mattie DR, Braverman L, Keys DA, Mumtaz M, Fisher JW. Low-Dose Effects of Ammonium Perchlorate on the Hypothalamic-Pituitary-Thyroid Axis of Adult Male Rats Pretreated with PCB126. Toxicol Sci 2007; 97:308-17. [PMID: 17379623 DOI: 10.1093/toxsci/kfm063] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The objective of this research was to characterize the disturbances in the hypothalamic-pituitary-thyroid (HPT) axis resulting from exposure to a binary mixture, 3,3',4,4',5-pentachlorobiphenyl (PCB126) and perchlorate (ClO(4)(-)), known to cause hypothyroidism by different modes of action. Two studies were conducted to determine the HPT axis effects of ClO(4)(-) on adult male Sprague-Dawley rats pretreated with PCB126. In dosing study I, rats were administered a single oral dose of PCB126 (0, 7.5, or 75 microg/kg) on day 0 and 9 days later ClO(4)(-) (0, 0.01, 0.1, or 1 mg/kg day) was added to the drinking water until euthanasia on day 22. Significant dose-dependent trends were found for all thyroid function indices measured following ClO(4)(-) in drinking water for 14 days. Seventy-five micrograms PCB126/kg resulted in a significant increase in hepatic T(4)-glucuronide formation, causing a decline in serum thyroxine and fT(4), and resulting in increased serum thyroid-stimulating hormone (TSH). Serum TSH was also increased in animals that received 7.5 microg PCB126/kg; no other HPT axis alterations were found in these animals. When pretreated with PCB126, the ClO(4)(-) dose trends disappeared, suggesting a less than additive effect on the HPT axis. In dosing study II, animals were given lower doses of PCB126 (0, 0.075, 0.75, or 7.5 microg/kg) on day 0, and followed with ClO(4)(-) (0 or 0.01 mg/kg day) in drinking water beginning on day 1 and continuing for several days to explore transient HPT axis effects. No statistical effects were seen for PCB126 or ClO(4)(-) alone, and no perturbations were found when administered sequentially in dosing study II. In conclusion, these studies demonstrate that HPT axis disturbances following exposure to ClO(4)(-) are less than additive when pretreated with relatively high doses of PCB126. At relatively low doses, at or near the no-observed-effect-level for PCB126 and ClO(4)(-), no interactions between the chemicals occur.
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Affiliation(s)
- Eva D McLanahan
- Interdisciplinary Toxicology Program, University of Georgia, Athens, GA 30602, USA.
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Steinberg RM, Juenger TE, Gore AC. The effects of prenatal PCBs on adult female paced mating reproductive behaviors in rats. Horm Behav 2007; 51:364-72. [PMID: 17274994 PMCID: PMC2692581 DOI: 10.1016/j.yhbeh.2006.12.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 12/03/2006] [Accepted: 12/04/2006] [Indexed: 11/28/2022]
Abstract
Polychlorinated biphenyls (PCBs) are a family of toxicants that persist in measurable quantities in human and wildlife tissues, despite their ban in production in 1977. Some PCB mixtures can act as endocrine disrupting chemicals (EDCs) by mimicking or antagonizing the actions of hormones in the brain and periphery. When exposure to hormonally active substances such as PCBs occurs during vulnerable developmental periods, particularly prenatally or in early postnatal life, they can disrupt sex-specific patterning of the brain, inducing permanent changes that can later be manifested as improper sexual behaviors. Here, we investigated the effects of prenatal exposure to the PCB mixture Aroclor (A) 1221 on adult female reproductive behaviors in a dose-response model in the Sprague-Dawley rat. Using a paced mating paradigm that permits the female to set the timing of mating and control contact with the male during copulation, we were able to uncover significant differences in female-typical sexual activities in A1221-exposed females. Specifically, A1221 causes significant effects on mating trial pacing, vocalizations, ambulation and the female's likelihood to mate. The results further demonstrate that the intermediate treatment group has the greatest number of disrupted endpoints, suggestive of non-linear dose responses to A1221. These data demonstrate that the behavioral phenotype in adulthood is disrupted by low, ecologically relevant exposures to PCBs, and the results have implications for reproductive success and health in wildlife and women.
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Affiliation(s)
- Rebecca M Steinberg
- The Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
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Abstract
Complex technical mixtures of polychlorinated biphenyls (PCBs) cause liver and thyroid neoplasms in rodents, whereas very few data are available on the carcinogenic potency of single non-dioxinlike (NDL) PCB congeners. In most genotoxicity assays technical PCB mixtures and individual congeners were inactive, suggesting that PCBs act as indirect, nongenotoxic carcinogens. Various mechanisms, including suppression of apoptosis in preneoplastic cells or inhibition of intercellular communication, have been suggested to be active in liver tumor promotion by PCBs. A decrease in thyroid hormone levels after PCB treatment has been suggested to play a role in the development of thyroid neoplasms in rats; however, other mechanisms may also be involved. Results from a chronic carcinogenicity study in rats indicate that not the dose of total PCBs but the total TCDD or toxic equivalents (TEQs) associated with "dioxinlike" (DL) constituents within a technical mixture are mainly if not exclusively responsible for the development of liver neoplasms in female rats. Quantitative comparison reveals almost identical dose-response curves for the total TEQs in various technical PCB mixtures and for TCDD as inducers of hepatic neoplasms in female rats. Tumor promotion experiments have shown, however, that, after initiation with a genotoxic carcinogen, technical PCB mixtures and individual DL-and NDL-PCBs act as liver tumor promoters in rodents. Based on these data, a weak carcinogenic potency of individual NDL-PCB congeners cannot be excluded. In epidemiological studies, increased mortality from cancers of the liver, gallbladder, biliary tract, gastrointestinal tract, and from brain cancer and malignant melanoma were observed in workers exposed to a series of technical PCB mixtures. A significant association between PCB concentrations in adipose tissue and non-Hodgkins lymphoma was found in another study. While in all human studies mixed exposure to DL-and NDL-PCBs occurred, no comprehensive data are available on the relative contribution of NDL-PCBs to the overall external and/or internal PCB exposure in those cohorts.
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Affiliation(s)
- Stefanie Knerr
- Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Kaiserslautern, Germany
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Das K, Vossen A, Tolley K, Víkingsson G, Thron K, Müller G, Baumgärtner W, Siebert U. Interfollicular fibrosis in the thyroid of the harbour porpoise: an endocrine disruption? ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2006; 51:720-9. [PMID: 16465558 DOI: 10.1007/s00244-005-0098-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Accepted: 09/19/2005] [Indexed: 05/06/2023]
Abstract
Previous studies have described high levels of polychlorobiphenyls (PCB), polybrominated diphenylether (PBDE), toxaphene, p,p'-dichlorodiphenyltrichloroethane (DDT), and p,p'-dichlorodiphenyldichloroethylene (DDE) in the blubber of the harbour porpoise from the North Sea raising the question of a potential endocrine disruption in this species. In the present study, the thyroids of 57 harbour porpoises from the German and Danish (North and Baltic Seas), Norwegian, and Icelandic coasts have been collected for histological and immunohistological investigations. The number of follicles and the relative distribution of follicles, connective, and solid tissues (%) were quantified in the thyroid of each individual. Then, the potential relationship between the thyroid morphometry data and previously described organic compounds (namely, PCB, PBDE, toxaphene, DDT, and DDE) was investigated using factor analysis and multiple regressions. Thyroid morphology differed strongly between sampling sites. Porpoises from the German (North and Baltic Seas) and Norwegian coasts displayed a high percentage of connective tissues between 30 and 38% revealing severe interfollicular fibrosis and a high number of large follicles (diameter>200 microm). A correlation-based principal component analysis (PCA) revealed two principal components explaining 85.9% of the total variance. The variables PCB, PBDE, DDT, and DDE compounds loaded highest on PC1 whereas toxaphene compound loaded most on PC2. Our results pointed out a relationship between PC1 (PCBs, PBDE, DDE, and DDT compounds) and interfollicular fibrosis in the harbour porpoise thyroids. Such an association is not alone sufficient for a cause-effect relationship but supports the hypothesis of a contaminant-induced thyroid fibrosis in harbour porpoises raising the question of the long-term viability in highly polluted areas.
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Affiliation(s)
- Krishna Das
- Research- and Technology Centre Westcoast, Christian-Albrechts-University Kiel, Büsum, Germany.
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You F, Zhou YF, Zhang XE, Huang Z, Bi LJ, Zhang ZP, Wen JK, Chen YY, Jiang GB, Zheng MH. Cell-Free Bioassay for Measurement of Dioxins Based on Fluorescence Enhancement of Fluorescein Isothiocyanate-Labeled DNA Probe. Anal Chem 2006; 78:7138-44. [PMID: 17037913 DOI: 10.1021/ac060442e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study aims to develop a rapid and sensitive cell-free bioassay of dioxins. It is known that dioxin ligand can bind heterodimeric aryl hydrocarbon receptor (AhR) and triggers the formation of the complex of dioxin-AhR, AhR nuclear translocator (ARNT), and dioxin-responsive element (DRE) region of the DNA. The hypothesis of the proposed method is that if FITC were labeled at the DRE sequence, its fluorescence intensity would be enhanced when the complex forms because the interaction interface of the binding components (AhR, ARNT, and DRE) creates a rather hydrophobic condition that is in favor of FITC emission. Effects of modification site of FITC on the DNA probes on binding efficiency between the complex components and fluorescence emission enhancement were evaluated by surface plasmon resonance and fluorescence analysis, respectively. Results showed that the labeling site at the second base at the 5' end apart from the core region (5'-TNGCGTG-3') of DRE did not obviously interfere with the binding between the DNA probe and dioxin-AhR/ARNT hybrid but presented significant fluorescence emission enhancement. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as the typical toxin in this study. The method had a linear range of 1-100 pM, with detection limit of 0.1 pM (0.64 fg/assay) and coefficient of variation of 5.6% (n = 10, 50 pM TCDD in transformed cytosol). The whole detection cycle was approximately 4 h. The method was also used to estimate the toxic equivalents (TEQ) of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD) and 1,2,3,4,7,8-hexachlorodibenzo-p-dioxin (HxCDD). Measurement of TEQs of the mixture of TCDD, PeCDD, and HxCDD were highly consistent with the predicted data. The average recovery using fly ash extract was approximately 93%.
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Affiliation(s)
- Fan You
- Joint Research Group on Analytical Pathogen Microbiology Wuhan Institute of Virology, Wuhan 430071, China
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Yamauchi K, Ishihara A. Thyroid system-disrupting chemicals: interference with thyroid hormone binding to plasma proteins and the cellular thyroid hormone signaling pathway. REVIEWS ON ENVIRONMENTAL HEALTH 2006; 21:229-51. [PMID: 17243349 DOI: 10.1515/reveh.2006.21.4.229] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
In vertebrates, thyroid hormones are essential for post-embryonic development, such as establishing the central nervous system in mammals and metamorphosis in amphibians. The present paper summarizes the possible extra-thyroidal processes that environmental chemicals are known to or suspected to target in the thyroid hormone-signaling pathway. We describe how such chemicals interfere with thyroid-hormone-binding protein functions in plasma, thyroid-hormone-uptake system, thyroid-hormone-metabolizing enzymes, and activation or suppression of thyroid-hormone-responsive genes through thyroid-hormone receptors in mammals and amphibian tadpoles. Several organohalogens affect different aspects of the extra-thyroidal thyroid-hormone-signaling pathway but hardly affect thyroid hormone binding to receptors. Rodents and amphibian tadpoles are most sensitive to the effects of environmental chemicals during specific thyroid-hormone-related developmental windows. Possible mechanisms by which environmental chemicals exert multipotent activities beyond one hormone-signaling pathway are discussed.
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Affiliation(s)
- Kiyoshi Yamauchi
- Department of Biological Science, Faculty of Science, Shizuoka University, Suruga-ku, Shizuoka, Japan.
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Champoux L, Rodrigue J, Trudeau S, Boily MH, Spear PA, Hontela A. Contamination and biomarkers in the great blue heron, an indicator of the state of the st. Lawrence river. ECOTOXICOLOGY (LONDON, ENGLAND) 2006; 15:83-96. [PMID: 16400530 DOI: 10.1007/s10646-005-0043-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Accepted: 06/22/2005] [Indexed: 05/06/2023]
Abstract
In 1996-1997, nine breeding colonies of the great blue heron on the St. Lawrence River and its estuary (Québec, Canada) were investigated in the framework of a biomonitoring program. Fledglings from colonies in freshwater were more contaminated with mercury, PCBs and many organic contaminants than those from estuarine colonies. The level of contamination in the St. Lawrence River is generally below the levels of toxicological effects for the great blue heron. The molar ratio of retinol: retinyl palmitate in heron eggs was correlated with total PCBs (r=0.79) and Mirex (r=0.90). In plasma, all biochemical parameters were significantly different between freshwater and marine colonies. Plasma retinol concentrations at the Dickerson and Hérons colonies were significantly lower compared with those at Grande Ile (p<0.05) and Steamboat (p<0.001). Based on retinoid and beta-carotene concentrations in eggs, low plasma retinol was not associated with possible dietary deficiency. Plasma retinol was negatively correlated with many PCB congeners, total PCBs (r=-0.78), p,p'-DDE, trans-nonachlor and alpha-HCH. Similarly, the hormone T3 was correlated with many PCB congeners, total PCBs (r=-0.69) and the same organochlorine chemicals. Plasma LDH concentrations were different among freshwater colonies, Grande Ile and Hérons colonies having LDH values significantly greater than those of Steamboat (respectively, p<0.05 and p<0.01). Globally, the health status of the St. Lawrence great blue heron population was judged to be acceptable, however, several biomarkers indicated positive responses to contaminants.
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Affiliation(s)
- Louise Champoux
- Environment Canada, Canadian Wildlife Service, C.P. 10100, G1V 4H5, Ste-Foy, Québec, Canada.
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Giacomini SM, Hou L, Bertazzi PA, Baccarelli A. Dioxin effects on neonatal and infant thyroid function: routes of perinatal exposure, mechanisms of action and evidence from epidemiology studies. Int Arch Occup Environ Health 2005; 79:396-404. [PMID: 16217675 DOI: 10.1007/s00420-005-0049-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Accepted: 09/20/2005] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Animal experiments suggest that thyroid function alterations in newborns and infants may represent one of the most sensitive markers of toxicity from 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Dioxin can be transferred from the mother to the offspring either in utero or through lactation. It has been suggested that thyroid-hormone alterations produced by dioxin in utero or shortly after birth may underlie long-term effects, such as cognitive-ability and neurodevelopment impairment. In the present review article, we appraise available evidence on the effects of perinatal exposure to dioxin on fetal and infant thyroid function. METHODS We summarized the routes of perinatal dioxin exposure and research results on possible mechanisms of dioxin toxic effects on thyroid function. We performed a systematic review of epidemiology studies conducted on mother-child pairs exposed to background environmental levels to investigate dioxin effects on neonatal and infant thyroid function. RESULTS Toxicological and mechanistic data indicate that dioxin may impair thyroid function in exposed newborns and infants. Investigations on background-exposed children have not consistently demonstrated an association between perinatal TCDD exposure and thyroid function, although some of the studies suggest that sub-clinical hypothyroidism may be induced by perinatal dioxin exposure within 3 months from birth. Between studies inconsistencies may be related to lab method differences, mixed exposures, and small sample size of the populations evaluated. CONCLUSION Epidemiology studies have as yet failed to demonstrate an association between perinatal TCDD exposure and thyroid function alterations in human subjects, although suggestive evidence from animal and in-vitro experimental data is available.
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Affiliation(s)
- Sara Mariasole Giacomini
- EPOCA Epidemiology Research Center, Department of Environmental and Occupational Health Clinica del Lavoro L. Devoto, Maggiore Hospital Foundation IRCCS, University of Milan, via San Barnaba 8, 20122, Milan, Italy
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Ohta C, Haraguchi K, Kato Y, Koga N. In vitro metabolism of 2,2',3,4',5,5',6-heptachlorobiphenyl (CB187) by liver microsomes from rats, hamsters and guinea pigs. Xenobiotica 2005; 35:319-30. [PMID: 16019954 DOI: 10.1080/00498250500087507] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The metabolism of 2,2',3,4',5,5',6-heptachlorobiphenyl (heptaCB) (CB187) was studied using liver microsomes of rats, hamsters and guinea pigs, and the effect of cytochrome P450 (CYP) inducers, phenobarbital (PB) and 3-methylcholanthrene (MC), was also investigated. In untreated animals, guinea pig liver microsomes formed three metabolites which were deduced to be 4'-hydroxy-2,2',3,5,5',6-hexachlorobiphenyl (M-1), 4'-hydroxy-2,2',3,3',5,5',6-heptaCB (M-2) and 4-OH-CB187 (M-3) from the comparison of GC/MS data with some synthetic authentic samples. The formation rate of M-1, M-2 and M-3 was 18.1, 36.6, 14.7 pmol h-1 mg protein-1, respectively. Liver microsomes of untreated rats and hamsters did not form CB187 metabolites. In guinea pigs, PB-treatment increased M-1 and M-2 significantly to 1.9- and 3.4-fold of untreated animals but did not affect the formation of M-3. In rats, PB-treatment resulted in the appearance of M-2 and M-3 with formation rates of 87.1 and 13.7 pmol h-1 mg protein-1, respectively, but M-1 was not observed. In hamsters, PB-treatment formed only M-2 at a rate of 29.4 pmol h-1 mg protein-1. On the other hand, MC-treatment of guinea pigs decreased the formation of M-1 and M-2 to less than 50% of untreated animals. MC-microsomes of rats and hamsters produced no metabolites. Preincubation of antiserum (300 microl) against guinea pig CYP2B18 with liver microsomes of PB-treated guinea pigs produced 80% inhibition of M-1 and the complete inhibition of M-2 and M-3. These results suggest that PB-inducible CYP forms, especially guinea pig CYP2B18, rat CYP2B1 and hamster CYP2B, are important in CB187 metabolism and that CB187 metabolism in guinea pigs may proceed via the formation of 3,4- or 3',4'-oxide and subsequent NIH-shift or dechlorination.
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Affiliation(s)
- C Ohta
- Faculty of Nutritional Sciences, Nakamura Gakuen University, Johnan-ku, Fukuoka, Japan
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Daidoji T, Gozu K, Iwano H, Inoue H, Yokota H. UDP-GLUCURONOSYLTRANSFERASE ISOFORMS CATALYZING GLUCURONIDATION OF HYDROXY-POLYCHLORINATED BIPHENYLS IN RAT. Drug Metab Dispos 2005; 33:1466-76. [PMID: 16006569 DOI: 10.1124/dmd.105.004416] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are highly toxic environmental contaminants that can cause irreversible damage in humans and wildlife. The mechanism of toxicity is not clear, but biotransformation products such as hydroxy PCBs (OH-PCBs) are a major concern. Efforts to elucidate the metabolism of PCBs and their metabolites, however, have paid little attention to the structure of the compound to be eliminated. The objectives of this study were to clarify organ tissue distribution of the glucuronidation activities toward OH-PCBs and to determine the UDP-glucuronosyltranseferase (UGT) isoforms responsible for glucuronidation in relation to the OH-PCB structure. 2,4,6-Trichlorobiphenyl and 2,3,4,5-tetrachlorobiphenyl were incubated in primary culture of rat hepatocytes, and the metabolites were identified by HPLC. Organ tissue glucuronidation activities toward 10 OH-PCBs were investigated by reactions of microsomes prepared from brain, liver, small and large intestine, lung, kidney, and testis tissues. To determine substrate specificity of the isoforms toward the OH-PCBs, rat UGT isoforms UGT1A1, UGT1A3, UGT1A5, UGT1A6, UGT1A7, UGT2B1, UGT2B3, and UGT2B12 were expressed in yeast strain AH22. Glucuronidation of the PCBs was found to be contingent on their hydroxylation. The organ tissues had strong glucuronidation activities toward the OH-PCBs tested; and most OH-PCBs were glucuronidated by UGT1A1, UGT1A6, and UGT2B1, all of which were substrate-specific. In conclusion, glucuronidation activities of UGT1A1, UGT1A6, and UGT2B1 toward OH-PCBs is relative to expression of the isoforms in each tissue, and glucuronidation intensity of the isoforms is relative to the structure of the OH-PCB to be glucuronidated.
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Affiliation(s)
- Tomo Daidoji
- Department of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069, Japan
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Debier C, Ylitalo GM, Weise M, Gulland F, Costa DP, Le Boeuf BJ, de Tillesse T, Larondelle Y. PCBs and DDT in the serum of juvenile California sea lions: associations with vitamins A and E and thyroid hormones. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2005; 134:323-32. [PMID: 15589659 DOI: 10.1016/j.envpol.2004.07.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 07/26/2004] [Indexed: 05/23/2023]
Abstract
Top-trophic predators like California sea lions bioaccumulate high levels of persistent fat-soluble pollutants that may provoke physiological impairments such as endocrine or vitamins A and E disruption. We measured circulating levels of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in 12 healthy juvenile California sea lions captured on Año Nuevo Island, California, in 2002. We investigated the relationship between the contamination by PCBs and DDT and the circulating levels of vitamins A and E and thyroid hormones (thyroxine, T4 and triiodothyronine, T3). Serum concentrations of total PCBs (sigmaPCBs) and total DDT were 14 +/- 9 mg/kg and 28 +/- 19 mg/kg lipid weight, respectively. PCB toxic equivalents (sigmaPCB TEQs) were 320 +/- 170 ng/kg lipid weight. Concentrations of sigmaPCBs and sigmaPCB TEQs in serum lipids were negatively correlated (p < 0.05) with serum vitamin A and T3, potentially reflecting PCB-related toxicity. A slight but not significant negative correlation (p < 0.1) was observed between serum T4 and the levels of sigmaPCBs and sigmaPCB TEQs. Conversely, no relationship was evident between the contaminant concentrations and vitamin E (p > 0.1). As juvenile California sea lions are useful sentinels of coastal contamination, the high levels encountered in their serum is cause for concern about the ecosystem health of the area.
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Affiliation(s)
- Cathy Debier
- Unité de Biochimie de la Nutrition, Université catholique de Louvain, Croix du Sud 2/8, B-1348 Louvain-la-Neuve, Belgium.
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Skarman E, Darnerud PO, Ohrvik H, Oskarsson A. Reduced thyroxine levels in mice perinatally exposed to polybrominated diphenyl ethers. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 19:273-281. [PMID: 21783486 DOI: 10.1016/j.etap.2004.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Accepted: 08/03/2004] [Indexed: 05/31/2023]
Abstract
The aim of the study was to follow plasma thyroxine levels and hepatic enzyme activities in offspring after maternal gestational and lactational exposure to polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls. Mice were given 10 equimolar oral doses from gestational day (GD) 4 to postnatal day (PND) 17 of either Bromkal 70-5DE, 2,2',4,4',5-pentabrominated diphenyl ether (BDE-99) or Aroclor 1254 (total dose of 0.80mmol/kg, b.w.). Plasma thyroxine levels were reduced in offspring in the Aroclor and Bromkal groups on PND11 but had returned to control levels by PND37. No effects on thyroxine levels were seen in the dams. Hepatic activity of EROD was increased in all treated offspring groups and so was UDP-GT in Aroclor-exposed offspring on PND11 and PND18. This study shows that PBDEs and PCBs, probably after microsomal transformation, have endocrine disrupting properties in perinatally exposed juvenile mice, most pronounced at PND11. However, BDE-99 had no effect on thyroxine levels, suggesting that other components in Bromkal are responsible for the hypothyroxinemia.
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Affiliation(s)
- Ellen Skarman
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, PO Box 7078, SE-75007 Uppsala, Sweden
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Bérubé VE, Boily MH, DeBlois C, Dassylva N, Spear PA. Plasma retinoid profile in bullfrogs, Rana catesbeiana, in relation to agricultural intensity of sub-watersheds in the Yamaska River drainage basin, Québec, Canada. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2005; 71:109-120. [PMID: 15642636 DOI: 10.1016/j.aquatox.2004.10.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 08/14/2004] [Accepted: 10/06/2004] [Indexed: 05/24/2023]
Abstract
Amphibian populations are decreasing globally and the causes are presently unclear. Retinoids have been extensively studied in other vertebrate classes where they are associated with pleiotropic effects such as susceptibility to disease (including cancer and parasitic infections), deformities and reproduction. To investigate the hypothesis that retinoid homeostasis is influenced by agricultural activities, blood samples were collected from adult bullfrogs, Rana catesbeiana, at each of six sub-watersheds chosen to represent a gradient of agricultural intensity within the Yamaska River drainage basin. Samples of surface water were collected at each of the study sites approximately 1 month after spraying and analyzed for 53 pesticides. Male body weight was significantly different (p<0.001) between study sites with the smallest bullfrogs captured from the Rivière à la Barbue sub-watershed associated with high agricultural intensity. A significant linear regression (p<0.001; R2=0.176) was obtained between plasma retinol and body weight. Plasma retinol concentrations were significantly different between study sites (p<0.001) being lowest at both Rivière Noire and Rivière à la Barbue. More than 60% of the land area in these sub-watersheds is under intensive corn-soya cultivation and surface water contained the highest concentrations of the herbicides atrazine, deethyl-atrazine, simazine, metolachlor, dimethenamide, chlopyralide, dicamba and bentazone. Plasma 13-cis-4-oxo-retinoic acid was significantly different (p<0.001) between sub-watersheds, however this effect was apparently unrelated to agricultural intensity. Plasma retinol was negatively correlated (p=0.026; r=-0.237) with plasma 13-cis-4-oxo-retinoic acid. These results suggest that retinoid homeostasis in bullfrogs may be influenced by agricultural practices.
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Affiliation(s)
- Virginie E Bérubé
- Centre de Recherche TOXEN and Département des Sciences Biologiques, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montréal, Qué., Canada H3C 3P8
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