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Sabatino L, Lapi D, Del Seppia C. Factors and Mechanisms of Thyroid Hormone Activity in the Brain: Possible Role in Recovery and Protection. Biomolecules 2024; 14:198. [PMID: 38397435 PMCID: PMC10886502 DOI: 10.3390/biom14020198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/29/2024] [Accepted: 02/03/2024] [Indexed: 02/25/2024] Open
Abstract
Thyroid hormones (THs) are essential in normal brain development, and cognitive and emotional functions. THs act through a cascade of events including uptake by the target cells by specific cell membrane transporters, activation or inactivation by deiodinase enzymes, and interaction with nuclear thyroid hormone receptors. Several thyroid responsive genes have been described in the developing and in the adult brain and many studies have demonstrated a systemic or local reduction in TH availability in neurologic disease and after brain injury. In this review, the main factors and mechanisms associated with the THs in the normal and damaged brain will be evaluated in different regions and cellular contexts. Furthermore, the most common animal models used to study the role of THs in brain damage and cognitive impairment will be described and the use of THs as a potential recovery strategy from neuropathological conditions will be evaluated. Finally, particular attention will be given to the link observed between TH alterations and increased risk of Alzheimer's Disease (AD), the most prevalent neurodegenerative and dementing condition worldwide.
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Affiliation(s)
- Laura Sabatino
- Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56124 Pisa, Italy;
| | - Dominga Lapi
- Department of Biology, University of Pisa, 56127 Pisa, Italy;
| | - Cristina Del Seppia
- Institute of Clinical Physiology, National Council of Research, Via Moruzzi 1, 56124 Pisa, Italy;
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Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Grasl‐Kraupp B, Hogstrand C, (Ron) Hoogenboom L, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Wallace H, Benford D, Fürst P, Hart A, Rose M, Schroeder H, Vrijheid M, Ioannidou S, Nikolič M, Bordajandi LR, Vleminckx C. Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food. EFSA J 2024; 22:e8497. [PMID: 38269035 PMCID: PMC10807361 DOI: 10.2903/j.efsa.2024.8497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024] Open
Abstract
The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.
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Souza MCO, Devóz PP, Ximenez JPB, Bocato MZ, Rocha BA, Barbosa F. Potential Health Risk to Brazilian Infants by Polybrominated Diphenyl Ethers Exposure via Breast Milk Intake. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph191711138. [PMID: 36078850 PMCID: PMC9517810 DOI: 10.3390/ijerph191711138] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 05/13/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) are ubiquitous flame retardants and are environmentally persistent. PBDEs show endocrine disruption, neurotoxicity, and lower birth weight in infants, and their human body burden has become a public health concern. The infants' exposure begins in the prenatal period and continues via breast milk ingestion, although, little is known about the factors that may influence this exposure. In this study, PBDE levels in Brazilian breast milk were assessed in 200 lactating women. The risk assessment of infants' exposure to PBDE was performed through the estimated daily intake (EDI) calculation. The geometric mean (GM) of ∑PBDEs levels was 2.33 (0.14-6.05) ng/g wet weight. At least one PBDE congener was detected in the samples, and the 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) showed a 100% of detection rate (GM of 1.05 ng/g). Location of residence, maternal level education, monthly salary, and race were positively associated with PBDE levels (p < 0.05). The EDI of BDE-47 was higher in Belo Horizonte (8.29 ng/kg/day) than in Viçosa (6.36 ng/kg/day), as well as for the ∑PBDEs (19.77 versus 12.78 ng/kg/day) (p < 0.05). Taking the high detection rate of PBDEs in breast milk and their toxicity, continuous studies on infant exposure, fetal growth, and child neurodevelopment are requested.
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Marty MS, Sauer UG, Charlton A, Ghaffari R, Guignard D, Hallmark N, Hannas BR, Jacobi S, Marxfeld HA, Melching-Kollmuss S, Sheets LP, 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 III: how is substance-mediated thyroid hormone imbalance in pregnant/lactating rats or their progeny related to neurodevelopmental effects? Crit Rev Toxicol 2022; 52:546-617. [PMID: 36519295 DOI: 10.1080/10408444.2022.2130166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This review investigated which patterns of thyroid- and brain-related effects are seen in rats upon gestational/lactational exposure to 14 substances causing thyroid hormone imbalance by four different modes-of-action (inhibition of thyroid peroxidase, sodium-iodide symporter and deiodinase activities, enhancement of thyroid hormone clearance) or to dietary iodine deficiency. Brain-related parameters included motor activity, cognitive function, acoustic startle response, hearing function, periventricular heterotopia, electrophysiology and brain gene expression. Specific modes-of-action were not related to specific patterns of brain-related effects. Based upon the rat data reviewed, maternal serum thyroid hormone levels do not show a causal relationship with statistically significant neurodevelopmental effects. Offspring serum thyroxine together with offspring serum triiodothyronine and thyroid stimulating hormone appear relevant to predict the likelihood for neurodevelopmental effects. Based upon the collated database, thresholds of ≥60%/≥50% offspring serum thyroxine reduction and ≥20% and statistically significant offspring serum triiodothyronine reduction indicate an increased likelihood for statistically significant neurodevelopmental effects; accuracies: 83% and 67% when excluding electrophysiology (and gene expression). Measurements of brain thyroid hormone levels are likely relevant, too. The extent of substance-mediated thyroid hormone imbalance appears more important than substance mode-of-action to predict neurodevelopmental impairment in rats. Pertinent research needs were identified, e.g. to determine whether the phenomenological offspring thyroid hormone thresholds are relevant for regulatory toxicity testing. The insight from this review shall be used to suggest a tiered testing strategy to determine whether gestational/lactational substance exposure may elicit thyroid hormone imbalance and potentially also neurodevelopmental effects.
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Affiliation(s)
| | - Ursula G Sauer
- Scientific Consultancy-Animal Welfare, Neubiberg, Germany
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Ramhøj L, Svingen T, Mandrup K, Hass U, Lund SP, Vinggaard AM, Hougaard KS, Axelstad M. Developmental exposure to the brominated flame retardant DE-71 reduces serum thyroid hormones in rats without hypothalamic-pituitary-thyroid axis activation or neurobehavioral changes in offspring. PLoS One 2022; 17:e0271614. [PMID: 35853081 PMCID: PMC9295973 DOI: 10.1371/journal.pone.0271614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022] Open
Abstract
Polybrominated diphenyl ethers (PBDEs) are legacy flame retardants for which human exposure remains ubiquitous. This is of concern since these chemicals can perturb development and cause adverse health effects. For instance, DE-71, a technical mixture of PBDEs, can induce liver toxicity as well as reproductive and developmental toxicity. DE-71 can also disrupt the thyroid hormone (TH) system which may induce developmental neurotoxicity indirectly. However, in developmental toxicity studies, it remains unclear how DE-71 exposure affects the offspring’s thyroid hormone system and if this dose-dependently relates to neurodevelopmental effects. To address this, we performed a rat toxicity study by exposing pregnant dams to DE-71 at 0, 40 or 60 mg/kg/day during perinatal development from gestational day 7 to postnatal day 16. We assessed the TH system in both dams and their offspring, as well as potential hearing and neurodevelopmental effects in prepubertal and adult offspring. DE-71 significantly reduced serum T4 and T3 levels in both dams and offspring without a concomitant upregulation of TSH, thus inducing a hypothyroxinemia-like effect. No discernible effects were observed on the offspring’s brain function when assessed in motor activity boxes and in the Morris water maze, or on offspring hearing function. Our results, together with a thorough review of the literature, suggest that DE-71 does not elicit a clear dose-dependent relationship between low serum thyroxine (T4) and effects on the rat brain in standard behavioral assays. However, low serum TH levels are in themselves believed to be detrimental to human brain development, thus we propose that we lack assays to identify developmental neurotoxicity caused by chemicals disrupting the TH system through various mechanisms.
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Affiliation(s)
- Louise Ramhøj
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
- * E-mail:
| | - Terje Svingen
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Karen Mandrup
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ulla Hass
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Søren Peter Lund
- National Research Centre for the Working Environment, Copenhagen, Denmark
| | | | - Karin Sørig Hougaard
- National Research Centre for the Working Environment, Copenhagen, Denmark
- Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Marta Axelstad
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark
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Duarte-Restrepo E, Noguera-Oviedo K, Butryn D, Wallace JS, Aga DS, Jaramillo-Colorado BE. Spatial distribution of pesticides, organochlorine compounds, PBDEs, and metals in surface marine sediments from Cartagena Bay, Colombia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:14632-14653. [PMID: 33216302 DOI: 10.1007/s11356-020-11504-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 11/02/2020] [Indexed: 05/12/2023]
Abstract
Cartagena Bay is an estuarine system located in the Caribbean Sea (Colombia, South America), that receives fresh water from Canal del Dique, which is connected to the Magdalena River, the most important river of Colombia, with some of the most prominent Colombian cities located in its watershed, which has a high sediment yield. An analysis of persistent organic pollutants and heavy metals was carried out on marine sediments from Cartagena Bay. Cartagena Bay sediments deployed the occurrence of total levels of pesticides (thiocarbamates, bromacil, triazines, organochlorines, and organophosphorus), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), in sediments ranging from 0.83-33.67 ng/g dry-weight, 0.05-0.34 ng/g dry-weight, and 0.06-19.58 ng/g dry-weight, respectively. Their concentrations were lower than those reported in NOAA Screening Quick Reference Tables. DDTs and PCBs are banned organochlorine compounds, since, even at low levels, their presence in sediments represents a threat to aquatic organisms and, therefore, to human health through the trophic chain. Sediments showed high concentrations of strontium (50-959.6 mg/kg). All metals evaluated in the marine sediments were found in the S6 sampling point; this was near tannery and hydrocarbon industries (Pb 37.1 mg/kg, Cr 137.2 mg/kg, Cd 1.7 mg/kg, Cu 64.4 mg/kg, As 13.1 mg/kg, Sr 318.9 mg/kg); these results exceeded the accepted values of threshold effect levels (TEL) used as an indicator of their potential risk on marine life.
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Affiliation(s)
- Edisson Duarte-Restrepo
- Agrochemical Research Group, Chemistry Program, Faculty of Exact and Natural Sciences, University of Cartagena, Cartagena, Colombia
- Doctoral Program in Environmental Toxicology, Pharmaceutical Sciences Faculty, University of Cartagena, Cartagena, Bolivar, Colombia
| | - Katia Noguera-Oviedo
- Chemistry Department, University at Buffalo, The State University of New York, 611 Natural Science Complex, Buffalo, NY, 14260, USA
| | - Deena Butryn
- Chemistry Department, University at Buffalo, The State University of New York, 611 Natural Science Complex, Buffalo, NY, 14260, USA
| | - Joshua S Wallace
- Chemistry Department, University at Buffalo, The State University of New York, 611 Natural Science Complex, Buffalo, NY, 14260, USA
| | - Diana S Aga
- Chemistry Department, University at Buffalo, The State University of New York, 611 Natural Science Complex, Buffalo, NY, 14260, USA.
| | - Beatriz E Jaramillo-Colorado
- Agrochemical Research Group, Chemistry Program, Faculty of Exact and Natural Sciences, University of Cartagena, Cartagena, Colombia.
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Graceli JB, Dettogni RS, Merlo E, Niño O, da Costa CS, Zanol JF, Ríos Morris EA, Miranda-Alves L, Denicol AC. The impact of endocrine-disrupting chemical exposure in the mammalian hypothalamic-pituitary axis. Mol Cell Endocrinol 2020; 518:110997. [PMID: 32841708 DOI: 10.1016/j.mce.2020.110997] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/15/2022]
Abstract
The hypothalamic-pituitary axis (HP axis) plays a critical and integrative role in the endocrine system control to maintain homeostasis. The HP axis is responsible for the hormonal events necessary to regulate the thyroid, adrenal glands, gonads, somatic growth, among other functions. Endocrine-disrupting chemicals (EDCs) are a worldwide public health concern. There is growing evidence that exposure to EDCs such as bisphenol A (BPA), some phthalates, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and biphenyls (PBBs), dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and atrazine (ATR), is associated with HP axis abnormalities. EDCs act on hormone receptors and their downstream signaling pathways and can interfere with hormone synthesis, metabolism, and actions. Because the HP axis function is particularly sensitive to endogenous hormonal changes, disruptions by EDCs can alter HP axis proper function, leading to important endocrine irregularities. Here, we review the evidence that EDCs could directly affect the mammalian HP axis function.
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Affiliation(s)
- Jones B Graceli
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Raquel S Dettogni
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Eduardo Merlo
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Oscar Niño
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Charles S da Costa
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Jordana F Zanol
- Department of Morphology, Health Sciences Center, Federal University of Espirito Santo. Av. Marechal Campos, 1468, CEP: 290440-090 Vitória, ES, Brazil.
| | - Eduardo A Ríos Morris
- Laboratory of Experimental Endocrinology-LEEx, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil. Graduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Brazil.
| | - Leandro Miranda-Alves
- Laboratory of Experimental Endocrinology-LEEx, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil. Graduate Program in Endocrinology, Faculty of Medicine, Federal University of Rio de Janeiro, Brazil. Graduate Program in Pharmacology and Medicinal Chemistry, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil.
| | - Anna C Denicol
- Department of Animal Science, University of California, Davis, One Shields Avenue Davis, CA, 95616, USA.
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Koslowski S, Latapy C, Auvray P, Blondel M, Meijer L. Long-Term Fipronil Treatment Induces Hyperactivity in Female Mice. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E1579. [PMID: 32121376 PMCID: PMC7084594 DOI: 10.3390/ijerph17051579] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 12/27/2022]
Abstract
Fipronil is an insecticide widely used for veterinary and agricultural purposes. While its insecticidal properties mostly rely on its high affinity antagonistic activity on insect γ aminobutyric acid (GABA) receptors, fipronil and its main metabolite fipronil sulfone nevertheless display non-negligible affinity for mammalian GABAA receptor. As several environmental toxicants have been shown to raise the risk of developing various neurodegenerative disorders, the aim of this study was to evaluate whether long-term low dose administration of fipronil could lead to cognitive deficiencies. Our results indicate that long-term fipronil treatment leads to behavioral perturbations in mice, indicating an accumulative effect of sustained exposure to low dose of fipronil. Although no memory impairment was observed during the course of our study, we noticed a significant hyperlocomotion behavior after 43 weeks of weekly fipronil administration, which is consistent with its direct effect on the GABAergic system.
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Affiliation(s)
- Svenja Koslowski
- Perha Pharmaceuticals & ManRos Therapeutics, Centre de Perharidy, 29680 Roscoff, Bretagne, France;
- C.RIS Pharma, Parc Technopolitain, Atalante Saint Malo, 35400 Saint Malo, France; (C.L.); (P.A.)
| | - Camille Latapy
- C.RIS Pharma, Parc Technopolitain, Atalante Saint Malo, 35400 Saint Malo, France; (C.L.); (P.A.)
| | - Pierrïck Auvray
- C.RIS Pharma, Parc Technopolitain, Atalante Saint Malo, 35400 Saint Malo, France; (C.L.); (P.A.)
| | - Marc Blondel
- Université Brest, Inserm, EFS, UMR1078, GGB, F-29200 Brest, France;
- Service de Génétique clinique et de Biologie de la reproduction, CHRU (Centre Hospitalier Régional et Universitaire), F-29200 Brest, France
| | - Laurent Meijer
- Perha Pharmaceuticals & ManRos Therapeutics, Centre de Perharidy, 29680 Roscoff, Bretagne, France;
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Rantakokko P, Kumar E, Braber J, Huang T, Kiviranta H, Cequier E, Thomsen C. Concentrations of brominated and phosphorous flame retardants in Finnish house dust and insights into children's exposure. CHEMOSPHERE 2019; 223:99-107. [PMID: 30771653 DOI: 10.1016/j.chemosphere.2019.02.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/06/2019] [Accepted: 02/07/2019] [Indexed: 06/09/2023]
Abstract
Brominated and phosphorous flame retardants (BFRs, PFRs) are added to household and consumer products to reduce their flammability. Some FRs are persistent in the environment and may have adverse health effects. As exposure indoors contributes significantly to total exposure, we wanted to estimate the exposure of children (3 years of age) through dust ingestion, inhalation, and dermal absorption. We measured 17 BFRs and 10 PFRs in indoor dust, predicted their respective concentrations in the indoor air and assessed children's exposure. Among the BFRs, decabromodiphenyl ether (BDE-209) had highest median level in the dust (411 ng/g) followed by decabromodiphenyl ethane (DBDPE, 119 ng/g) and bis-ethylhexyl tetrabromophthalate (BEH-TEBP, 106 ng/g). Among the PFRs, trisbutoxyethyl phosphate (TBOEP) had the highest concentration (11100 ng/g) followed by tris(2-chloroisopropyl) phosphate (TCIPP, 1870 ng/g) and triphenyl phosphate (TPHP, 773 ng/g). FR concentration in air predicted from dust concentrations were within the interquartile range of experimental data for 10/13 of BFRs and 4/8 of PFRs compared. Dust ingestion was the major route of exposure (75-99%) for higher molecular weight BFRs, TBOEP and phenyl based PFRs (73-77%). Inhalation was important for volatile BFRs like pentabromobenzene (PBB 71%) and pentabromotoluene (PBT 52%) and dermal exposure for volatile chlorinated PFRs (TCEP 84%, TCIPP 77%). Margins of Exposure (MoE) were calculated as the ratio of total exposure to oral Reference Dose (RfD). MoEs were lowest for TCEP (220), TBOEP (240) and TCIPP (830), and > 1000 for all other FRs. These MoEs imply no risk for Finnish children by the studied FRs.
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Affiliation(s)
- Panu Rantakokko
- National Institute for Health and Welfare, Environmental Health Unit, P.O. Box 95, FI-70701, Kuopio, Finland.
| | - Eva Kumar
- National Institute for Health and Welfare, Environmental Health Unit, P.O. Box 95, FI-70701, Kuopio, Finland
| | - Joris Braber
- National Institute for Health and Welfare, Environmental Health Unit, P.O. Box 95, FI-70701, Kuopio, Finland; Rijn IJssel College, Laan van Scheut 2, 6525 EM, Nijmegen, the Netherlands
| | - Taya Huang
- National Institute for Health and Welfare, Environmental Health Unit, P.O. Box 95, FI-70701, Kuopio, Finland
| | - Hannu Kiviranta
- National Institute for Health and Welfare, Environmental Health Unit, P.O. Box 95, FI-70701, Kuopio, Finland
| | - Enrique Cequier
- Norwegian Institute of Public Health, Department of Environmental Exposure and Epidemiology, P.O. Box 4404, Nydalen, 0403, Oslo, Norway
| | - Cathrine Thomsen
- Norwegian Institute of Public Health, Department of Environmental Exposure and Epidemiology, P.O. Box 4404, Nydalen, 0403, Oslo, Norway
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Liang H, Vuong AM, Xie C, Webster GM, Sjödin A, Yuan W, Miao M, Braun JM, Dietrich KN, Yolton K, Lanphear BP, Chen A. Childhood polybrominated diphenyl ether (PBDE) serum concentration and reading ability at ages 5 and 8 years: The HOME Study. ENVIRONMENT INTERNATIONAL 2019; 122:330-339. [PMID: 30503319 PMCID: PMC6324196 DOI: 10.1016/j.envint.2018.11.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 11/09/2018] [Accepted: 11/12/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND Polybrominated diphenyl ethers (PBDEs) exist extensively in the environment and human beings. PBDE concentrations are higher in children than adults. A previous study found that prenatal PBDE exposure was associated with decreased reading skills in children; however, evidence is limited on the potential impact of childhood exposure to PBDEs. The study examined the association between childhood PBDE exposures and reading ability in children at ages 5 and 8 years. METHODS The study included 230 children from an ongoing prospective pregnancy and birth cohort study, the Health Outcomes and Measures of Environment (HOME) Study, conducted in Cincinnati, Ohio. Children's serum concentrations of eleven PBDE congeners were measured at 1, 2, 3, 5, and 8 years. The Woodcock-Johnson Tests of Achievement - III and the Wide Range Achievement Test - 4 were administered to assess children's reading skills at ages 5 and 8 years, respectively. We used multiple informant models to examine the associations between repeated measures of PBDEs and reading scores at ages 5 and 8 years. We also estimated the βs and 95% CIs of the association of PBDE measure at each age by including interaction terms between PBDE concentrations and child age in the models. RESULTS All childhood BDE-153 concentrations were inversely associated with reading scores at 5 and 8 years, but associations were not statistically significant after covariate adjustment. For example, a 10-fold increase in BDE-153 concentrations at ages 3 and 5 years was associated with a -5.0 (95% confidence interval (CI): -11.0, 1.0) and -5.5 (95% CI: -12.5, 1.4) point change in Basic Reading score at age 5 years, respectively. Similarly, the estimates for Brief Reading score at age 5 years were -4.5 (95% CI: -10.5, 1.5) and -5.2 (95% CI: -12.2, 1.7) point changes, respectively. Serum concentration of BDE-47, -99, -100, and Sum4PBDEs (sum of BDE-47, 99, 100, and 153) at every age were inversely associated with reading scores at ages 5 and 8 years in unadjusted analyses. While the adjusted estimates were much attenuated and became non-significant, the direction of most of the associations was not altered. CONCLUSION Our study has shown a suggestive but non-significant trend of inverse associations between childhood PBDE serum concentrations, particularly BDE-153, and children's reading skills. Future studies with a larger sample size are needed to examine these associations.
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Affiliation(s)
- Hong Liang
- Department of Reproductive Epidemiology and Social Medicine, NHC Key Lab of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Fudan University, Shanghai 200237, China; Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ann M Vuong
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Changchun Xie
- Division of Biostatistics and Bioinformatics, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Glenys M Webster
- BC Children's Hospital Research Institute, Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Andreas Sjödin
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Wei Yuan
- Department of Reproductive Epidemiology and Social Medicine, NHC Key Lab of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Fudan University, Shanghai 200237, China
| | - Maohua Miao
- Department of Reproductive Epidemiology and Social Medicine, NHC Key Lab of Reproduction Regulation (Shanghai Institute of Planned Parenthood Research), Fudan University, Shanghai 200237, China
| | - Joseph M Braun
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Kim N Dietrich
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kimberly Yolton
- Division of General and Community Pediatrics, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Bruce P Lanphear
- BC Children's Hospital Research Institute, Faculty of Health Sciences, Simon Fraser University, Vancouver, British Columbia, Canada
| | - Aimin Chen
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Dorman DC, Chiu W, Hales BF, Hauser R, Johnson KJ, Mantus E, Martel S, Robinson KA, Rooney AA, Rudel R, Sathyanarayana S, Schantz SL, Waters KM. Polybrominated diphenyl ether (PBDE) neurotoxicity: a systematic review and meta-analysis of animal evidence. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2018; 21:269-289. [PMID: 30352012 PMCID: PMC6786272 DOI: 10.1080/10937404.2018.1514829] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
A recent systematic review (SR) and meta-analysis of human studies found an association between prenatal serum polybrominated diphenyl ethers (PBDE) concentrations and a decrease in the IQ of children. A SR of experimental developmental animal PBDE-mediated neurotoxicity studies was performed in the present study. Outcomes assessed included measures related to learning, memory, and attention, which parallel the intelligence-related outcomes evaluated in the human studies SR. PubMed, Embase, and Toxline were searched for relevant experimental non-human mammalian studies. Evaluation of risk of bias (RoB) and overall body of evidence followed guidance developed by the National Toxicology Program. Animal studies using varying designs and outcomes were available for BDEs 47, 99, 153, 203, 206, and 209 and the technical mixture DE-71. Study reporting of methods and results was often incomplete leading to concerns regarding RoB. A meta-analysis of 6 Morris water maze studies showed evidence of a significant increase in last trial latency (effect size of 25.8 [CI, 20.3 to 31.2]) in PBDE-exposed animals with low heterogeneity. For most endpoints, there were unexplained inconsistencies across studies and no consistent evidence of a dose-response relationship. There is a "moderate" level of evidence that exposure to BDEs 47, 99, and 209 affects learning. For other PBDEs and other endpoints, the level of evidence was "low" or "very low". The meta-analysis led to stronger conclusions than that based upon a qualitative review of the evidence. The SR also identified RoB concerns that might be remedied by better study reporting.
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Affiliation(s)
- David C. Dorman
- Department of Molecular and Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Weihsueh Chiu
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Barbara F. Hales
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Russ Hauser
- Department of Environmental Health and Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Kamin J. Johnson
- Predictive Safety Center, Corteva Agriscience™, Agriculture Division of DowDuPont™, Indianapolis, IN, USA
| | - Ellen Mantus
- Board on Environmental Studies and Toxicology at the National Academies of Sciences, Engineering, and Medicine, Washington DC, USA
| | - Susan Martel
- Board on Environmental Studies and Toxicology at the National Academies of Sciences, Engineering, and Medicine, Washington DC, USA
| | - Karen A. Robinson
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew A. Rooney
- Office of Health Assessment and Translation, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | | | - Sheela Sathyanarayana
- Department of Pediatrics, University of Washington, Seattle Children’s Research Institute, Seattle WA, USA
| | - Susan L. Schantz
- Department of Comparative Biosciences, College of Veterinary Medicine and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Katrina M. Waters
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
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12
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Vuong AM, Braun JM, Webster GM, Thomas Zoeller R, Hoofnagle AN, Sjödin A, Yolton K, Lanphear BP, Chen A. Polybrominated diphenyl ether (PBDE) exposures and thyroid hormones in children at age 3 years. ENVIRONMENT INTERNATIONAL 2018; 117:339-347. [PMID: 29787984 PMCID: PMC5997562 DOI: 10.1016/j.envint.2018.05.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 05/06/2023]
Abstract
BACKGROUND Polybrominated diphenyl ethers (PBDEs) reduce serum thyroid hormone concentrations in animal studies, but few studies have examined the impact of early-life PBDE exposures on thyroid hormone disruption in childhood. METHODS We used data from 162 mother-child pairs from the Health Outcomes and Measures of the Environment Study (2003-2006, Cincinnati, OH). We measured PBDEs in maternal serum at 16 ± 3 weeks gestation and in child serum at 1-3 years. Thyroid hormones were measured in serum at 3 years. We used multiple informant models to investigate associations between prenatal and early-life PBDE exposures and thyroid hormone levels at age 3 years. RESULTS Prenatal PBDEs were associated with decreased thyroid stimulating hormone (TSH) levels at age 3 years. A 10-fold increase in prenatal ∑PBDEs (BDE-28, -47, -99, -100, and -153) was associated with a 27.6% decrease (95% CI -40.8%, -11.3%) in TSH. A ten-fold increase in prenatal ∑PBDEs was associated with a 0.25 pg/mL (0.07, 0.43) increase in free triiodothyronine (FT3). Child sex modified associations between prenatal PBDEs and thyroid hormones, with significant decrements in TSH among females and decreased free T4 (FT4) in males. Prenatal ∑PBDEs were not associated with TT4, FT4, or total T3. CONCLUSIONS These findings suggest an inverse relationship between prenatal ∑PBDEs and TSH at 3 years. Associations may be sexually dimorphic, with an inverse relationship between prenatal BDE-47 and -99 and TSH in females and null associations among males.
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Affiliation(s)
- Ann M Vuong
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, P.O. Box 670056, Cincinnati 45267, OH, USA
| | - Joseph M Braun
- Department of Epidemiology, Brown University School of Public Health, 121 South Main St, Box G-S121-2, Providence 02912, RI, USA
| | - Glenys M Webster
- BC Children's Hospital Research Institute and Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, BC, Canada
| | - R Thomas Zoeller
- Department of Biology, University of Massachusetts Amherst, 611 North Pleasant St, Amherst 01003, MA, USA
| | - Andrew N Hoofnagle
- Department of Laboratory Medicine, University of Washington, 1959 NE Pacific St, NW120, Seattle 98195, WA, USA
| | - Andreas Sjödin
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Mail Stop F-20, 4770 Buford Highway NE, Atlanta 30341, GA, USA
| | - Kimberly Yolton
- Division of General and Community Pediatrics, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, MLC 7035, Cincinnati 45229, OH, USA
| | - Bruce P Lanphear
- BC Children's Hospital Research Institute and Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, BC, Canada
| | - Aimin Chen
- Division of Epidemiology, Department of Environmental Health, University of Cincinnati College of Medicine, P.O. Box 670056, Cincinnati 45267, OH, USA.
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Zhuang J, Wang S, Shan Q, Zhang ZF, Li MQ, Zheng GH, Fan SH, Wu DM, Hu B, Lu J, Zheng YL. Adeno-associated virus vector-mediated expression of DJ-1 attenuates learning and memory deficits in 2, 2´, 4, 4´-tetrabromodiphenyl ether (BDE-47)-treated mice. JOURNAL OF HAZARDOUS MATERIALS 2018; 347:390-402. [PMID: 29335220 DOI: 10.1016/j.jhazmat.2018.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/18/2017] [Accepted: 01/03/2018] [Indexed: 06/07/2023]
Abstract
Evidence indicates that oxidative stress is the central pathological feature of 2, 2´, 4, 4´-tetrabromodiphenyl ether (BDE-47)-induced neurotoxicity. Protein kinase C delta (PKCδ), an oxidative stress-sensitive kinase, can be proteolytically cleaved to yield a catalytically active fragment (PKCδ-CF) that is involved in various neurodegenerative disorders. Here, we showed that BDE-47 treatment increased ROS, malondialdehyde, and protein carbonyl levels in the mouse hippocampus. In turn, excessive ROS induced caspase-3-dependent PKCδ activation and stimulated NF-κB p65 nuclear translocation, resulting in inflammation in the mouse hippocampus. These changes caused learning and memory deficits in BDE-47-treated mice. Treatment with Z-DEVD-fmk, a caspase-3 inhibitor, or N-acetyl-L-cysteine, an antioxidant, blocked PKCδ activation and subsequently inhibited inflammation, thereby improving learning and memory deficits in BDE-47-treated mice. Our data further showed that activation of ROS-PKCδ signaling was associated with DJ-1 downregulation, which exerted neuroprotective effects against oxidative stress induced by different neurotoxic agents. Adeno-associated viral vector-mediated DJ-1 overexpression in the hippocampus effectively inhibited excessive ROS production, suppressed caspase-3-dependent PKCδ cleavage, blunted inflammation and ultimately reversed learning and memory deficits in BDE-47-treated mice. Taken together, our results demonstrate that DJ-1 plays a pivotal role in BDE-47-induced neurotoxic effects and learning and memory deficits.
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Affiliation(s)
- Juan Zhuang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, Huaiyin Normal University, Huaian 223300, China; School of Life Sciences, Huaiyin Normal University, Huaian 223300, China
| | - Shan Wang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Qun Shan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Zi-Feng Zhang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Meng-Qiu Li
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Gui-Hong Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Shao-Hua Fan
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Dong-Mei Wu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
| | - Bin Hu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China
| | - Jun Lu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
| | - Yuan-Lin Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China; College of Health Sciences, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, China.
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Yu D, Zhou H, Zou L, Jiang Y, Wu X, Jiang L, Zhou Q, Yang Y, Xu L, Mao R. Hippocampal Administration of Levothyroxine Impairs Contextual Fear Memory Consolidation in Rats. Front Cell Neurosci 2017; 11:223. [PMID: 28824379 PMCID: PMC5534464 DOI: 10.3389/fncel.2017.00223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/13/2017] [Indexed: 12/17/2022] Open
Abstract
Thyroid hormone (TH) receptors are highly distributed in the hippocampus, which plays a vital role in memory processes. However, how THs are involved in the different stages of memory process is little known. Herein, we used hippocampus dependent contextual fear conditioning to address the effects of hippocampal THs on the different stages of fear memory. First, we found that a single systemic levothyroxine (LT4) administration increased the level of free triiodothyronine (FT3) and free tetraiodothyroxine (FT4) not only in serum but also in hippocampus. In addition, a single systemic LT4 administration immediately after fear conditioning significantly impaired fear memory. These results indicated the important role of hippocampal THs in fear memory process. To further confirm the effects of hippocampal THs on the different stages of fear memory, LT4 (0.4 μg/μl, 1 μl/side) was injected bilaterally into hippocampus. Rats given LT4 into hippocampus before training or tests had no effect on the acquisition or retrieval of fear memory, however rats given LT4 into hippocampus either immediately or 2 h after training showed being significantly impaired fear memory, which demonstrated LT4 administration into hippocampus impairs the consolidation but has no effect on the acquisition and retrieval of fear memory. Furthermore, hippocampal injection of LT4 did not affect rats’ locomotor activity, thigmotaxis and THs level in prefrontal cortex (PFC) and serum. These findings may have important implications for understanding mechanisms underlying contribution of THs to memory disorders.
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Affiliation(s)
- Dafu Yu
- Department of Nuclear Medicine, First People's Hospital of Yunnan ProvinceKunming, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China
| | - Heng Zhou
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China.,School of Life Sciences, University of Science and Technology of ChinaHefei, China
| | - Lin Zou
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical UniversityChongqing, China
| | - Yong Jiang
- Department of Nuclear Medicine, First People's Hospital of Yunnan ProvinceKunming, China
| | - Xiaoqun Wu
- Respiratory Department, First People's Hospital of Yunnan ProvinceKunming, China
| | - Lizhu Jiang
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China.,Department of Neuropsychopathy, Clinical Medical School, Dali UniversityDali, China
| | - Qixin Zhou
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China
| | - Yuexiong Yang
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China
| | - Lin Xu
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China
| | - Rongrong Mao
- Laboratory of Learning and Memory, Kunming Institute of Zoology, Chinese Academy of SciencesKunming, China
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15
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The flame retardant DE-71 (a mixture of polybrominated diphenyl ethers) inhibits human differentiated thyroid cell function in vitro. PLoS One 2017. [PMID: 28644858 PMCID: PMC5482471 DOI: 10.1371/journal.pone.0179858] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Normal thyroid function is essential for general growth and metabolism, but can be affected by endocrine disrupting chemicals (EDCs). Polybrominated diphenyl ethers (PBDEs) have been used worldwide to reduce flammability in different materials and are suspected to be EDCs. The production of the commercial Penta- and OctaBDE mixtures is banned, but DecaBDEs and existing products may leak PBDEs into the environment. Our aim was to investigate the effect of the PentaBDE mixture DE-71 on human thyroid cells in vitro. MATERIALS AND METHODS Primary human thyroid cells were obtained as paraadenomatous tissue and cultured in monolayers. The influence of DE-71 on cyclic adenosine monophosphate (cAMP) and thyroglobulin (Tg) production was examined in the culture medium by competitive radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Real-time quantitative PCR analysis of thyroid-specific genes was performed on the exposed cell cultures. PBDE concentrations were determined in cellular and supernatant fractions of the cultures. RESULTS DE-71 inhibited Tg-release from TSH-stimulated thyrocytes. At 50 mg/L DE-71, mean Tg production was reduced by 71.9% (range: 8.5-98.7%), and cAMP by 95.1% (range: 91.5-98.8%) compared to controls). Expression of mRNA encoding Tg, TPO and TSHr were significantly inhibited (p<0.0001, p = 0.0079, and p = 0.0002, respectively). The majority of DE-71 added was found in the cell fraction. No cytotoxicity was found. CONCLUSIONS DE-71 inhibited differentiated thyroid cell functions in a two phase response manner and a concentration-dependent inhibition of Tg and cAMP production, respectively, as well as expression of mRNA encoding Tg, TPO and TSHr. Our findings suggest an inhibiting effect of PBDEs on thyroid cells.
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16
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Raymaekers SR, Darras VM. Thyroid hormones and learning-associated neuroplasticity. Gen Comp Endocrinol 2017; 247:26-33. [PMID: 28390960 DOI: 10.1016/j.ygcen.2017.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/30/2017] [Accepted: 04/03/2017] [Indexed: 12/11/2022]
Abstract
Thyroid hormones (THs) are crucial for brain development and maturation in all vertebrates. Especially during pre- and perinatal development, disruption of TH signaling leads to a multitude of neurological deficits. Many animal models provided insight in the role of THs in brain development, but specific data on how they affect the brain's ability to learn and adapt depending on environmental stimuli are rather limited. In this review, we focus on a number of learning processes like spatial learning, fear conditioning, vocal learning and imprinting behavior and on how abnormal TH signaling during development shapes subsequent performance. It is clear from multiple studies that TH deprivation leads to defects in learning on all fronts, and interestingly, changes in local expression of the TH activator deiodinase type 2 seem to have an important role. Taking into account that THs are regulated in a very space-specific manner, there is thus increasing pressure to investigate more local TH regulators as potential factors involved in neuroplasticity. As these learning processes are also important for proper adult human functioning, further elucidating the role of THs in developmental neuroplasticity in various animal models is an important field for advancing both fundamental and applied knowledge on human brain function.
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Affiliation(s)
- Sander R Raymaekers
- Laboratory of Comparative Endocrinology, Biology Department, KU Leuven, Naamsestraat 61, 3000 Leuven, Belgium
| | - Veerle M Darras
- Laboratory of Comparative Endocrinology, Biology Department, KU Leuven, Naamsestraat 61, 3000 Leuven, Belgium.
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