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Gonnabathula P, Choi MK, Li M, Kabadi SV, Fairman K. Utility of life stage-specific chemical risk assessments based on New Approach Methodologies (NAMs). Food Chem Toxicol 2024; 190:114789. [PMID: 38844066 DOI: 10.1016/j.fct.2024.114789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 05/17/2024] [Accepted: 06/03/2024] [Indexed: 06/17/2024]
Abstract
The safety assessments for chemicals targeted for use or expected to be exposed to specific life stages, including infancy, childhood, pregnancy and lactation, and geriatrics, need to account for extrapolation of data from healthy adults to these populations to assess their human health risk. However, often adequate and relevant toxicity or pharmacokinetic (PK) data of chemicals in specific life stages are not available. For such chemicals, New Approach Methodologies (NAMs), such as physiologically based pharmacokinetic (PBPK) modeling, biologically based dose response (BBDR) modeling, in vitro to in vivo extrapolation (IVIVE), etc. can be used to understand the variability of exposure and effects of chemicals in specific life stages and assess their associated risk. A life stage specific PBPK model incorporates the physiological and biochemical changes associated with each life stage and simulates their impact on the absorption, distribution, metabolism, and elimination (ADME) of these chemicals. In our review, we summarize the parameterization of life stage models based on New Approach Methodologies (NAMs) and discuss case studies that highlight the utility of a life stage based PBPK modeling for risk assessment. In addition, we discuss the utility of artificial intelligence (AI)/machine learning (ML) and other computational models, such as those based on in vitro data, as tools for estimation of relevant physiological or physicochemical parameters and selection of model. We also discuss existing gaps in the available toxicological datasets and current challenges that need to be overcome to expand the utility of NAMs for life stage-specific chemical risk assessment.
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Affiliation(s)
- Pavani Gonnabathula
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Me-Kyoung Choi
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Miao Li
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Shruti V Kabadi
- Center for Food Safety and Applied Nutrition (CFSAN), US Food and Drug Administration (FDA), College Park, MD, 20740, USA
| | - Kiara Fairman
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA.
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Bagga AD, Johnson BP, Zhang Q. Spatially Dependent Tissue Distribution of Thyroid Hormones by Plasma Thyroid Hormone Binding Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.20.572629. [PMID: 38187691 PMCID: PMC10769377 DOI: 10.1101/2023.12.20.572629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Plasma thyroid hormone (TH) binding proteins (THBPs), including thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin (ALB), carry THs to extrathyroidal sites, where THs are unloaded locally and then taken up via membrane transporters into the tissue proper. The respective roles of THBPs in supplying THs for tissue uptake are not completely understood. To investigate this, we developed a spatial human physiologically based kinetic (PBK) model of THs, which produces several novel findings. (1) Contrary to postulations that TTR and/or ALB are the major local T4 contributors, the three THBPs may unload comparable amounts of T4 in Liver, a rapidly perfused organ; however, their contributions in slowly perfused tissues follow the order of abundances of T4TBG, T4TTR, and T4ALB. The T3 amounts unloaded from or loaded onto THBPs in a tissue acting as a T3 sink or source respectively follow the order of abundance of T3TBG, T3ALB, and T3TTR regardless of perfusion rate. (2) Any THBP alone is sufficient to maintain spatially uniform TH tissue distributions. (3) The TH amounts unloaded by each THBP species are spatially dependent and nonlinear in a tissue, with ALB being the dominant contributor near the arterial end but conceding to TBG near the venous end. (4) Spatial gradients of TH transporters and metabolic enzymes may modulate these contributions, producing spatially invariant or heterogeneous TH tissue concentrations depending on whether the blood-tissue TH exchange operates in near-equilibrium mode. In summary, our modeling provides novel insights into the differential roles of THBPs in local TH tissue distribution.
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Affiliation(s)
- Anish D. Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA 30322, USA
| | - Brian P. Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA 30322, USA
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Bagga AD, Johnson BP, Zhang Q. A minimal human physiologically based kinetic model of thyroid hormones and chemical disruption of plasma thyroid hormone binding proteins. Front Endocrinol (Lausanne) 2023; 14:1168663. [PMID: 37305053 PMCID: PMC10248451 DOI: 10.3389/fendo.2023.1168663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/11/2023] [Indexed: 06/13/2023] Open
Abstract
The thyroid hormones (THs), thyroxine (T4) and triiodothyronine (T3), are under homeostatic control by the hypothalamic-pituitary-thyroid axis and plasma TH binding proteins (THBPs), including thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin (ALB). THBPs buffer free THs against transient perturbations and distribute THs to tissues. TH binding to THBPs can be perturbed by structurally similar endocrine-disrupting chemicals (EDCs), yet their impact on circulating THs and health risks are unclear. In the present study, we constructed a human physiologically based kinetic (PBK) model of THs and explored the potential effects of THBP-binding EDCs. The model describes the production, distribution, and metabolism of T4 and T3 in the Body Blood, Thyroid, Liver, and Rest-of-Body (RB) compartments, with explicit consideration of the reversible binding between plasma THs and THBPs. Rigorously parameterized based on literature data, the model recapitulates key quantitative TH kinetic characteristics, including free, THBP-bound, and total T4 and T3 concentrations, TH productions, distributions, metabolisms, clearance, and half-lives. Moreover, the model produces several novel findings. (1) The blood-tissue TH exchanges are fast and nearly at equilibrium especially for T4, providing intrinsic robustness against local metabolic perturbations. (2) Tissue influx is limiting for transient tissue uptake of THs when THBPs are present. (3) Continuous exposure to THBP-binding EDCs does not alter the steady-state levels of THs, while intermittent daily exposure to rapidly metabolized TBG-binding EDCs can cause much greater disruptions to plasma and tissue THs. In summary, the PBK model provides novel insights into TH kinetics and the homeostatic roles of THBPs against thyroid disrupting chemicals.
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Affiliation(s)
- Anish D. Bagga
- Emory College of Arts and Sciences, Emory University, Atlanta, GA, United States
| | - Brian P. Johnson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA, Atlanta, United States
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Zhang L, Jiang J, Jia W, Wan X, Li Y, Jiao J, Zhang Y. Physiologically-based toxicokinetic model for the prediction of perchlorate distribution and its application. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 318:120856. [PMID: 36513174 DOI: 10.1016/j.envpol.2022.120856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/16/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Perchlorate is a stable and readily transportable thyroid hormone disruptor, and prevalent exposure to perchlorate through food and drinking water has raised public concern about its health effects. The physiologically based toxicokinetic (PBTK) model as a dose prediction method is effective to predict the toxicant exposure dose of an organism and helps quantitatively assess the dose-dependent relationship with toxic effects. The current study aimed to establish a multi-compartment PBTK model based on updated time-course datasets of single oral exposure to perchlorate in rats. With adjustment of the kinetic parameters, the model fitted well the toxicokinetic characteristics of perchlorate in urine, blood, and thyroid from our experiments and the literature, and the coefficient of determination (R2) between the fitting values and the experimental data in regression analysis was greater than 0.91, indicating the robustness of the current model. The results of sensitivity analysis and daily repeated exposure simulations together confirmed its effective renal clearance. According to the distribution characteristic of perchlorate, a correlation study of internal and external exposure was conducted using urinary perchlorate as a bioassay indicator. The developed multi-compartment model for perchlorate updates important toxicokinetic data and kinetic parameters, providing analytical and modeling tools for deriving total exposure levels in the short term.
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Affiliation(s)
- Lange Zhang
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China; Department of Nutrition, School of Public Health, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Jiahao Jiang
- Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Wei Jia
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China; Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Xuzhi Wan
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China; Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Yaoran Li
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China; Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Jingjing Jiao
- Department of Nutrition, School of Public Health, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Yu Zhang
- Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, Zhejiang, China; Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China.
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Žabenský B, Bodor R, Makata D, Szucs R, Masár M. Trace determination of perchlorate in drinking water by capillary zone electrophoresis with isotachophoresis sample cleanup and conductivity detection. J Sep Sci 2022; 45:3339-3347. [PMID: 35661409 DOI: 10.1002/jssc.202200188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/05/2022] [Accepted: 06/02/2022] [Indexed: 11/05/2022]
Affiliation(s)
- Branislav Žabenský
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina CH2, Ilkovičova 6, Bratislava, 842 15, Slovakia
| | - Róbert Bodor
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina CH2, Ilkovičova 6, Bratislava, 842 15, Slovakia
| | - Dávid Makata
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina CH2, Ilkovičova 6, Bratislava, 842 15, Slovakia
| | - Roman Szucs
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina CH2, Ilkovičova 6, Bratislava, 842 15, Slovakia
| | - Marián Masár
- Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina CH2, Ilkovičova 6, Bratislava, 842 15, Slovakia
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Błażewicz A, Niziński P, Dolliver I, Dolliver W, Makarewicz A, Skórzyńska-Dziduszko K. Alterations of urinary perchlorate levels in euthyroid postpubertal children with autism spectrum disorder. J Trace Elem Med Biol 2021; 68:126800. [PMID: 34102587 DOI: 10.1016/j.jtemb.2021.126800] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/19/2021] [Accepted: 05/26/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Perchlorates ClO4(-) are known environmental and food contaminants that act as inhibitors of iodine uptake by the thyroid gland; however, information concerning their possible association with the development of autism spectrum disorder (ASD) is still missing. The current study is first presenting the alterations in perchlorate urine levels in euthyroid children with ASD. OBJECTIVES To examine urinary perchlorates and iodides in euthyroid children diagnosed with ASD, compared to age-, and BMI-matched neurotypical controls, and to verify the association between these two ions in ASD. METHODS Ions were determined in 24 h urine samples determined by ion chromatography-conductivity cell detection (IC-CD) and ion chromatography-pulsed amperometric detection (IC-PAD) techniques, respectively, in a total of 130 postpubertal euthyroid children with normal BMI (the mean age 14.46 years, SD = 1.32; the mean BMI 20.6, SD = 1.37), divided into age- and BMI-matched groups of ASD patients and neurotypical, healthy children (control). RESULTS The ASD group presented with significantly higher perchlorate urine levels than the controls (median = 1.05 μg/L, interquartile range(IQR) = 1.5 versus median = 0.09 μg/L, IQR = 0.097, respectively), as well as lower iodide urine levels (median = 100.2 μg/L, IQR = 37 versus median = 156.95 μg/L, IQR = 26.11, respectively). The ASD group presented significantly lower TSH and higher free thyroid hormone (fT4, fT3) levels than the controls. In regression analyses, perchlorate urine levels showed significant positive relationships with normal BMI values and serum TSH, and inverse relationships with serum fT4. Urinary iodide levels showed significant inverse relationships with BMI values. The absence of ASD was associated with decreased odds of perchlorate urine levels (OR = 0.012, 95 % confidence interval [CI] 0.0002-0.76), and increased odds of iodide urine levels (OR = 1.15, 95 %CI 1.05-1.27). CONCLUSIONS ASD may have an independent and significant impact on perchlorate as well as iodide levels in urine of euthyroid lean postpubertal children. Perchlorate levels do not appear to be directly associated with iodide levels in euthyroid children.
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Affiliation(s)
- Anna Błażewicz
- Department of Analytical Chemistry, Medical University of Lublin, 20-093, Lublin, Poland.
| | - Przemysław Niziński
- Department of Analytical Chemistry, Medical University of Lublin, 20-093, Lublin, Poland
| | - Iwona Dolliver
- Department of Analytical Chemistry, Medical University of Lublin, 20-093, Lublin, Poland
| | - Wojciech Dolliver
- The Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Agata Makarewicz
- Department of Psychiatry, Psychotherapy and Early Intervention, Medical University of Lublin, 20-439, Lublin, Poland
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Chou WC, Lin Z. Probabilistic human health risk assessment of perfluorooctane sulfonate (PFOS) by integrating in vitro, in vivo toxicity, and human epidemiological studies using a Bayesian-based dose-response assessment coupled with physiologically based pharmacokinetic (PBPK) modeling approach. ENVIRONMENT INTERNATIONAL 2020; 137:105581. [PMID: 32087483 DOI: 10.1016/j.envint.2020.105581] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/21/2020] [Accepted: 02/12/2020] [Indexed: 05/20/2023]
Abstract
BACKGROUND Environmental exposure to perfluorooctane sulfonate (PFOS) is associated with various adverse outcomes in humans. However, risk assessment for PFOS with the traditional risk estimation method is faced with multiple challenges because there are high variabilities and uncertainties in its toxicokinetics and toxicity between species and among different types of studies. OBJECTIVES This study aimed to develop a robust probabilistic risk assessment framework accounting for interspecies and inter-experiment variabilities and uncertainties to derive the human equivalent dose (HED) and reference dose for PFOS. METHODS A Bayesian dose-response model was developed to analyze selected 34 critical studies, including human epidemiological, animal in vivo, and ToxCast in vitro toxicity datasets. The dose-response results were incorporated into a multi-species physiologically based pharmacokinetic (PBPK) model to reduce the toxicokinetic/toxicodynamic variabilities. In addition, a population-based probabilistic risk assessment of PFOS was performed for Asian, Australian, European, and North American populations, respectively, based on reported environmental exposure levels. RESULTS The 5th percentile of HEDs derived from selected studies was estimated to be 21.5 (95% CI: 10.6-36.3) ng/kg/day. After exposure to environmental levels of PFOS, around 50% of the population in all studied populations would likely have >20% of increase in serum cholesterol, but the effects on other endpoints were estimated to be minimal (<10% changes). There was a small population (~10% of the population) that was highly sensitive to endocrine disruption and cellular response by environmental PFOS exposure. CONCLUSION Our results provide insights into a complete risk characterization of PFOS and may help regulatory agencies in the reevaluation of PFOS risk. Our new probabilistic approach can conduct dose-response analysis of different types of toxicity studies simultaneously and this method could be used to improve risk assessment for other perfluoroalkyl substances (PFAS).
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Affiliation(s)
- Wei-Chun Chou
- Institute of Computational Comparative Medicine (ICCM), Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, United States.
| | - Zhoumeng Lin
- Institute of Computational Comparative Medicine (ICCM), Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, United States.
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Hines DE, Conolly RB, Jarabek AM. A Quantitative Source-to-Outcome Case Study To Demonstrate the Integration of Human Health and Ecological End Points Using the Aggregate Exposure Pathway and Adverse Outcome Pathway Frameworks. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11002-11012. [PMID: 31436975 DOI: 10.1021/acs.est.9b04639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Exposure to environmental contaminants can lead to adverse outcomes in both human and nonhuman receptors. The Aggregate Exposure Pathway (AEP) and Adverse Outcome Pathway (AOP) frameworks can mechanistically inform cumulative risk assessment for human health and ecological end points by linking together environmental transport and transformation, external exposure, toxicokinetics, and toxicodynamics. This work presents a case study of a hypothetical contaminated site to demonstrate a quantitative approach for implementing the AEP framework and linking this framework to AOPs. We construct an AEP transport and transformation model and then quantify external exposure pathways for humans, fishes, and small herbivorous mammals at the hypothetical site. A Monte Carlo approach was used to address parameter variability. Source apportionment was quantified for each species, and published pharmacokinetic models were used to estimate internal target site exposure from external exposures. Published dose-response data for a multispecies AOP network were used to interpret AEP results in the context of species-specific effects. This work demonstrates (1) the construction, analysis, and application of a quantitative AEP model, (2) the utility of AEPs for organizing mechanistic exposure data and highlighting data gaps, and (3) the advantages provided by a source-to-outcome construct for leveraging exposure data and to aid transparency regarding assumptions.
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Affiliation(s)
- David E Hines
- U.S. Environmental Protection Agency , Office of Research and Development, National Health and Environmental Effects Research Laboratory, Integrated Systems Toxicology Division , Research Triangle Park, Durham , North Carolina 27709 , United States
| | - Rory B Conolly
- U.S. Environmental Protection Agency , Office of Research and Development, National Health and Environmental Effects Research Laboratory, Integrated Systems Toxicology Division , Research Triangle Park, Durham , North Carolina 27709 , United States
| | - Annie M Jarabek
- U.S. Environmental Protection Agency , Office of Research and Development, National Center for Environmental Assessment , Research Triangle Park, Durham , North Carolina 27709 , United States
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A model of functional thyroid disease status over the lifetime. PLoS One 2019; 14:e0219769. [PMID: 31318913 PMCID: PMC6638952 DOI: 10.1371/journal.pone.0219769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 07/01/2019] [Indexed: 11/23/2022] Open
Abstract
Mathematical models of the natural history of disease can predict incidence rates based on prevalence data and support simulations of populations where thyroid function affects other aspects of physiology. We developed a Markov chain model of functional thyroid disease status over the lifetime. Subjects were in one of seven thyroid disease states at any given point in their lives [normal, subclinical hypothyroidism, overt hypothyroidism, treated thyroid disease (ever), subclinical hyperthyroidism, overt hyperthyroidism, and reverted to normal thyroid status]. We used a Bayesian approach to fitting model parameters. A priori probabilities of changing from each disease state to another per unit time were based on published data and summarized using meta-analysis, when possible. The probabilities of changing state were fitted to observed prevalence data based on the National Health and Nutrition Examination Survey 2007–2012. The fitted model provided a satisfactory fit to the observed prevalence data for each disease state, by sex and decade of age. For example, for males 50–59 years old, the observed prevalence of ever having treated thyroid disease was 4.4% and the predicted value was 4.6%. Comparing the incidence rates of treated disease predicted from our model with published values revealed that 82% were within a 4-fold difference. The differences seemed to be systematic and were consistent with expectation based on national iodine intakes. The model provided new and comprehensive estimates of functional thyroid disease incidence rates for the U.S. Because the model provides a reasonable fit to national prevalence data and predicts thyroid disease status over the lifetime, it is suitable for simulating populations, thereby making possible quantitative bias analyses of selected epidemiologic data reporting an association of thyroid disease with serum concentrations of environmental contaminants.
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An evaluation of the USEPA Proposed Approaches for applying a biologically based dose-response model in a risk assessment for perchlorate in drinking water. Regul Toxicol Pharmacol 2019; 103:237-252. [DOI: 10.1016/j.yrtph.2019.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/18/2019] [Accepted: 01/20/2019] [Indexed: 12/18/2022]
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Lebsir D, Manens L, Grison S, Lestaevel P, Ebrahimian T, Suhard D, Phan G, Dublineau I, Tack K, Benderitter M, Pech A, Jourdain JR, Souidi M. Effects of repeated potassium iodide administration on genes involved in synthesis and secretion of thyroid hormone in adult male rat. Mol Cell Endocrinol 2018; 474:119-126. [PMID: 29496566 DOI: 10.1016/j.mce.2018.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND A single dose of potassium iodide (KI) is recommended to reduce the risk of thyroid cancer during nuclear accidents. However in case of prolonged radioiodine exposure, more than one dose of KI may be necessary. This work aims to evaluate the potential toxic effect of repeated administration of KI. METHODS Adult Wistar rats received an optimal dose of KI 1 mg/kg over a period of 1, 4 or 8 days. RESULTS hormonal status (TSH, FT4) of treated rats was unaffected. Contrariwise, a sequential Wolff-Chaikoff effect was observed, resulting in a prompt decrease of NIS and MCT8 mRNA expression (-58% and -26% respectively), followed by a delayed decrease of TPO mRNA expression (-33%) in conjunction with a stimulation of PDS mRNA expression (+62%). CONCLUSION we show for the first time that repeated administration of KI at 1 mg/kg/24h doesn't cause modification of thyroid hormones level, but leads to a reversible modification of the expression of genes involved in the synthesis and secretion of thyroid hormones.
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Affiliation(s)
- Dalila Lebsir
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - Line Manens
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - Stephane Grison
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - Philippe Lestaevel
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - Teni Ebrahimian
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - David Suhard
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SDI, LRC, 92262 Fontenay-aux-Roses, France
| | - Guillaume Phan
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SDI, LRC, 92262 Fontenay-aux-Roses, France
| | - Isabelle Dublineau
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, 92262 Fontenay-aux-Roses, France
| | - Karine Tack
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France
| | - Marc Benderitter
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, 92262 Fontenay-aux-Roses, France
| | - Annick Pech
- Pharmacie centrale des armées, Direction des Approvisionnement en produits de Santé des Armées, 45000 Orléans, France
| | - Jean-Rene Jourdain
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, 92262 Fontenay-aux-Roses, France
| | - Maâmar Souidi
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-HOM, SRBE, LRTOX, 92262 Fontenay-aux-Roses, France.
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Serrano-Nascimento C, Calil-Silveira J, Dalbosco R, Zorn TT, Nunes MT. Evaluation of hypothalamus-pituitary-thyroid axis function by chronic perchlorate exposure in male rats. ENVIRONMENTAL TOXICOLOGY 2018; 33:209-219. [PMID: 29139221 DOI: 10.1002/tox.22509] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 06/07/2023]
Abstract
Perchlorate is a widespread endocrine disruptor that was previously correlated with increased serum TSH levels and decreased thyroid hormones production both in animals and humans. Even so, the regulation of gene/protein expression in the hypothalamus, pituitary and thyroid by chronic perchlorate exposure was not completely elucidated. Therefore, this study aimed to investigate the underlying mechanisms involved in the disruption of hypothalamus-pituitary-thyroid axis by chronic perchlorate exposure. Male Wistar rats were treated or not with NaClO4 in the drinking water (35 mg/Kg/day) for 60 days. Thereafter, hormone/cytokines serum levels were measured through multiplex assays; genes/proteins expression were investigated by qPCR/Western Blotting and thyroid morphology was evaluated through histological analysis. Serum TSH levels were increased and serum T4 /T3 levels were decreased in perchlorate-treated animals. This treatment also altered the thyrotropin-releasing hormone mRNA/protein content in the hypothalamus. Additionally, the expression of both subunits of TSH were increased in the pituitary of perchlorate-treated rats, which also presented significant alterations in the thyroid morphology/gene expression. Furthermore, perchlorate exposure reduced liver Dio1 mRNA expression and increased the content of pro-inflammatory cytokines in the thyroid and the serum. In conclusion, our study adds novel findings about the perchlorate-induced disruption of the hypothalamus-pituitary-thyroid axis gene/protein expression in male rats. The data presented herein also suggest that perchlorate induces thyroid and systemic inflammation through the increased production of cytokines. Taken together, our results suggest that perchlorate contamination should be monitored, especially in the individuals most susceptible to the deleterious effects of reduced levels of thyroid hormones.
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Affiliation(s)
| | - Jamile Calil-Silveira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - Rafael Dalbosco
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - Telma Tenorio Zorn
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - Maria Tereza Nunes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
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Axthammer QJ, Klapötke TM, Krumm B. Studies on the synthesis and properties of 1,1,1-trinitroprop-2-yl urea, carbamate and nitrocarbamate. ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 2016. [DOI: 10.1515/znb-2016-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Potential high energetic dense oxidizers with the 1,1,1-trinitropropan-2-yl moiety are described in this study. The urea, N,N′-bis(1,1,1-trinitropropan-2-yl)urea (1), is synthesized by the reaction of urea with acetaldehyde and trinitromethane. The reaction of 1,1,1-trinitropropan-2-ol (2) with the reagent chlorosulfonyl isocyanate results in the formation of 1,1,1-trinitroprop-2-yl carbamate (3). The nitration of 3 with anhydrous nitric and sulfuric acid yields the nitrocarbamate (4). All compounds were fully characterized by multinuclear NMR (1H, 13C, 14/15N) and vibrational spectroscopy, mass spectrometry and elemental analysis (C,H,N). For analysis of the thermostability differential scanning calorimetry (DSC) was used. Energetic properties, the sensitivities towards impact, friction and electrostatic discharge were tested and compared with the corresponding 2,2,2-trinitroethyl and 3,3,3-trinitropropyl derivatives. The crystal structures of two compounds with that of the 1,1,1-trinitroprop-2-yl moiety have been determined by low temperature X-ray diffraction and discussed. The energies of formation were evaluated and several detonation parameters such as the velocity of detonation and the propulsion performance were calculated with the program package explo5.
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Affiliation(s)
- Quirin J. Axthammer
- Department of Chemistry , Energetic Materials Research, Ludwig-Maximilian University of Munich , Butenandtstraße 5–13 (D), 81377 Munich, Germany
| | - Thomas M. Klapötke
- Department of Chemistry , Energetic Materials Research, Ludwig-Maximilian University of Munich , Butenandtstraße 5–13 (D), 81377 Munich, Germany, Fax: +49-89-2180-77492
| | - Burkhard Krumm
- Department of Chemistry , Energetic Materials Research, Ludwig-Maximilian University of Munich , Butenandtstraße 5–13 (D), 81377 Munich, Germany
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14
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Fisher W, Wang J, George NI, Gearhart JM, McLanahan ED. Dietary Iodine Sufficiency and Moderate Insufficiency in the Lactating Mother and Nursing Infant: A Computational Perspective. PLoS One 2016; 11:e0149300. [PMID: 26930410 PMCID: PMC4773173 DOI: 10.1371/journal.pone.0149300] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/29/2016] [Indexed: 12/27/2022] Open
Abstract
The Institute of Medicine recommends that lactating women ingest 290 μg iodide/d and a nursing infant, less than two years of age, 110 μg/d. The World Health Organization, United Nations Children’s Fund, and International Council for the Control of Iodine Deficiency Disorders recommend population maternal and infant urinary iodide concentrations ≥ 100 μg/L to ensure iodide sufficiency. For breast milk, researchers have proposed an iodide concentration range of 150–180 μg/L indicates iodide sufficiency for the mother and infant, however no national or international guidelines exist for breast milk iodine concentration. For the first time, a lactating woman and nursing infant biologically based model, from delivery to 90 days postpartum, was constructed to predict maternal and infant urinary iodide concentration, breast milk iodide concentration, the amount of iodide transferred in breast milk to the nursing infant each day and maternal and infant serum thyroid hormone kinetics. The maternal and infant models each consisted of three sub-models, iodide, thyroxine (T4), and triiodothyronine (T3). Using our model to simulate a maternal intake of 290 μg iodide/d, the average daily amount of iodide ingested by the nursing infant, after 4 days of life, gradually increased from 50 to 101 μg/day over 90 days postpartum. The predicted average lactating mother and infant urinary iodide concentrations were both in excess of 100 μg/L and the predicted average breast milk iodide concentration, 157 μg/L. The predicted serum thyroid hormones (T4, free T4 (fT4), and T3) in both the nursing infant and lactating mother were indicative of euthyroidism. The model was calibrated using serum thyroid hormone concentrations for lactating women from the United States and was successful in predicting serum T4 and fT4 levels (within a factor of two) for lactating women in other countries. T3 levels were adequately predicted. Infant serum thyroid hormone levels were adequately predicted for most data. For moderate iodide deficient conditions, where dietary iodide intake may range from 50 to 150 μg/d for the lactating mother, the model satisfactorily described the iodide measurements, although with some variation, in urine and breast milk. Predictions of serum thyroid hormones in moderately iodide deficient lactating women (50 μg/d) and nursing infants did not closely agree with mean reported serum thyroid hormone levels, however, predictions were usually within a factor of two. Excellent agreement between prediction and observation was obtained for a recent moderate iodide deficiency study in lactating women. Measurements included iodide levels in urine of infant and mother, iodide in breast milk, and serum thyroid hormone levels in infant and mother. A maternal iodide intake of 50 μg/d resulted in a predicted 29–32% reduction in serum T4 and fT4 in nursing infants, however the reduced serum levels of T4 and fT4 were within most of the published reference intervals for infant. This biologically based model is an important first step at integrating the rapid changes that occur in the thyroid system of the nursing newborn in order to predict adverse outcomes from exposure to thyroid acting chemicals, drugs, radioactive materials or iodine deficiency.
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Affiliation(s)
- W. Fisher
- US FDA, National Center for Toxicological Research, 3900 NCTR Rd, Jefferson, Arkansas, 72079, United States of America
- * E-mail:
| | - Jian Wang
- US FDA, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Silver Springs, Maryland, 20993, United States of America
| | - Nysia I. George
- US FDA, National Center for Toxicological Research, 3900 NCTR Rd, Jefferson, Arkansas, 72079, United States of America
| | - Jeffery M. Gearhart
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, 2729 R Street, Bldg 837, Wright-Patterson AFB, Ohio, 43433, United States of America
- Wright State University Boonshoft School of Medicine, Dayton, Ohio, 45435, United States of America
| | - Eva D. McLanahan
- CDC/ATSDR, Division of Community Health Investigations, 4770 Buford HWY NE, Atlanta, Georgia, 30341, United States of America
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15
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Chen HX, Ding MH, Li YG, Liu Q, Peng KL. Dose-Response Relationship Between Orally Administered Ammonium Perchlorate and Urine Perchlorate Concentrations in Rats: Possible Biomarker to Quantify Environmental Ammonium Perchlorate Exposure on Thyroid Homeostasis. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2015; 70:286-290. [PMID: 24972017 DOI: 10.1080/19338244.2014.904265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To evaluate the feasibility of urine perchlorate as a biomarker of ammonium perchlorate (AP) exposure and to explore the correlation between the thyroid function indicators and the perchlorate concentrations, a sensitive and selective ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) method was developed to detect perchlorate in urine samples. Rats were orally administrated with different doses of perchlorate. Serum free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were determined by radioimmunoassays. The results showed that a dose of AP up to 520 mg kg(-1) body weight induced a significant increase of TSH, with a decrease of FT4. Particularly, the levels of urine perchlorate increased dose-dependently on AP exposure from drinking water. The findings highlighted that urine perchlorate may be a useful biomarker for AP environmental exposure.
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Affiliation(s)
- Hong Xia Chen
- a Institute of Biomedicine, Taihe Hospital , Hubei University of Medicine , Shiyan , People's Republic of China
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16
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Crawford-Brown D. Regulatory Implications of Cumulative Risk for Perchlorate as an Iodide Uptake Inhibitor. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/jep.2015.67066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Change of iodine load and thyroid homeostasis induced by ammonium perchlorate in rats. ACTA ACUST UNITED AC 2014; 34:672-678. [DOI: 10.1007/s11596-014-1335-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/20/2014] [Indexed: 10/24/2022]
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18
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Lee S, Ji K, Choi K. Effects of water temperature on perchlorate toxicity to the thyroid and reproductive system of Oryzias latipes. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2014; 108:311-317. [PMID: 25108511 DOI: 10.1016/j.ecoenv.2014.07.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 05/24/2014] [Accepted: 07/14/2014] [Indexed: 06/03/2023]
Abstract
Water temperature is expected to increase in many parts of the world due to global climate change. The change in water temperature may affect ecosystems through alterations of the chemical properties or by affecting the susceptibility of organisms. Perchlorate can disrupt thyroid function of an organism by inhibiting iodide uptake. In the present study, the effect of water temperature on perchlorate toxicity was evaluated using Japanese medaka (Oryzias latipes). Pairs of adult medaka fish were exposed to a sublethal concentration of sodium perchlorate (100mg/L) and a control, at a 'low' (26°C), 'medium' (29°C) or 'high' water temperature (33°C) for seven days. The effects of the water temperature on reproduction, thyroid hormones and cortisol concentrations were determined. Transcription of several genes related to thyroid function and stress were also investigated. Significant down-regulation of thyroid hormone receptor alpha (THR-α) and beta (THR-β) transcripts and up-regulation of deiodinase 2 (DIO2) transcripts were observed in the fish exposed to perchlorate. Thyroxine (T4) concentrations were decreased, while triiodothyronine (T3) levels remained constant following exposure to perchlorate, and this effect became more pronounced under the high water temperature conditions (33°C). Up-regulation of the DIO2 gene may explain these observations. The total number of spawned eggs decreased slightly as the water temperature increased, and this reduction became significant when fish were exposed to perchlorate. Our observations indicate that exposure to perchlorate could affect thyroid function and overall reproductive fitness, and these effects could be aggravated under high water temperatures.
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Affiliation(s)
- Sangwoo Lee
- School of Public Health, Seoul National University, Seoul 151-742, Republic of Korea
| | - Kyunghee Ji
- Department of Occupational and Environmental Health, Yongin University, Yongin 449-714, Republic of Korea
| | - Kyungho Choi
- School of Public Health, Seoul National University, Seoul 151-742, Republic of Korea.
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19
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The hypothalamic-pituitary-thyroid axis in infants and children: protection from radioiodines. J Thyroid Res 2014; 2014:710178. [PMID: 24971190 PMCID: PMC4058186 DOI: 10.1155/2014/710178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/07/2014] [Indexed: 11/17/2022] Open
Abstract
Potassium iodide (KI) is recommended as an emergency treatment for exposure to radioiodines, most commonly associated with nuclear detonation or mishaps at nuclear power plants. Protecting the thyroid gland of infants and children remains a priority because of increased incidence of thyroid cancer in the young exposed to radioiodines (such as (131)I and (133)I). There is a lack of clinical studies for KI and radioiodines in children or infants to draw definitive conclusions about the effectiveness and safety of KI administration in the young. In this paper, we compare functional aspects of the hypothalamic-pituitary-thyroid (HPT) axis in the young and adults and review the limited studies of KI in children. The HPT axis in the infant and child is hyperactive and therefore will respond less effectively to KI treatment compared to adults. Research on the safety and efficacy of KI in infants and children is needed.
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20
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McLanahan ED, White P, Flowers L, Schlosser PM. The use of PBPK models to inform human health risk assessment: case study on perchlorate and radioiodide human lifestage models. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2014; 34:356-366. [PMID: 23901895 DOI: 10.1111/risa.12101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Physiologically-based pharmacokinetic (PBPK) models are often submitted to or selected by agencies, such as the U.S. Environmental Protection Agency (U.S. EPA) and Agency for Toxic Substances and Disease Registry, for consideration for application in human health risk assessment (HHRA). Recently, U.S. EPA evaluated the human PBPK models for perchlorate and radioiodide for their ability to estimate the relative sensitivity of perchlorate inhibition on thyroidal radioiodide uptake for various population groups and lifestages. The most well-defined mode of action of the environmental contaminant, perchlorate, is competitive inhibition of thyroidal iodide uptake by the sodium-iodide symporter (NIS). In this analysis, a six-step framework for PBPK model evaluation was followed, and with a few modifications, the models were determined to be suitable for use in HHRA to evaluate relative sensitivity among human lifestages. Relative sensitivity to perchlorate was determined by comparing the PBPK model predicted percent inhibition of thyroidal radioactive iodide uptake (RAIU) by perchlorate for different lifestages. A limited sensitivity analysis indicated that model parameters describing urinary excretion of perchlorate and iodide were particularly important in prediction of RAIU inhibition; therefore, a range of biologically plausible values available in the peer-reviewed literature was evaluated. Using the updated PBPK models, the greatest sensitivity to RAIU inhibition was predicted to be the near-term fetus (gestation week 40) compared to the average adult and other lifestages; however, when exposure factors were taken into account, newborns were found to be populations that need further evaluation and consideration in a risk assessment for perchlorate.
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Affiliation(s)
- Eva D McLanahan
- U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, USA
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21
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Paul KB, Hedge JM, Rotroff DM, Hornung MW, Crofton KM, Simmons SO. Development of a Thyroperoxidase Inhibition Assay for High-Throughput Screening. Chem Res Toxicol 2014; 27:387-99. [DOI: 10.1021/tx400310w] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Katie B. Paul
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Joan M. Hedge
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Daniel M. Rotroff
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Michael W. Hornung
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Kevin M. Crofton
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Steven O. Simmons
- Oak Ridge Institute for Science
Education Postdoctoral Fellow, ‡Integrated Systems
Toxicology Division, §Mid-Continent Ecology Division, National Health and Environmental
Effects Research Laboratory, and ∥National Center for Computational Toxicology,
Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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22
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Paul KB, Hedge JM, Macherla C, Filer DL, Burgess E, Simmons SO, Crofton KM, Hornung MW. Cross-species analysis of thyroperoxidase inhibition by xenobiotics demonstrates conservation of response between pig and rat. Toxicology 2013; 312:97-107. [DOI: 10.1016/j.tox.2013.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/02/2013] [Accepted: 08/09/2013] [Indexed: 10/26/2022]
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23
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Lumen A, Mattie DR, Fisher JW. Evaluation of Perturbations in Serum Thyroid Hormones During Human Pregnancy Due to Dietary Iodide and Perchlorate Exposure Using a Biologically Based Dose-Response Model. Toxicol Sci 2013; 133:320-41. [DOI: 10.1093/toxsci/kft078] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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24
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Kirk AB, Dyke JV, Ohira SI, Dasgupta PK. Relative source contributions for perchlorate exposures in a lactating human cohort. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 443:939-943. [PMID: 23253938 DOI: 10.1016/j.scitotenv.2012.11.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 11/20/2012] [Accepted: 11/20/2012] [Indexed: 06/01/2023]
Abstract
Perchlorate is an iodine-uptake inhibitor and common contaminant of food and drinking water. Understanding the amount of perchlorate exposure occurring through non-water sources is essential for accurate estimates of human exposure levels, and establishment of drinking water limits for this pervasive contaminant. The study objective was to determine the amount of perchlorate intake derived from diet rather than water. Subjects provided drinking water samples, detailed fluid-intake records, 24h urine collections and four milk samples for nine days. Samples were analyzed for perchlorate by isotope dilution ion chromatography-tandem mass spectrometry. Amounts of perchlorate derived from drinking water and dietary sources were calculated for each individual. Water of local origin was found to contribute a minor fraction of perchlorate intake. Estimated fraction intake from drinking water ranged from 0 to 36%. The mean and median dose of perchlorate derived from non-water sources by lactating women was 0.18 μg/kg/day (range: 0.06 to 0.36 μg/kg/day.) Lactating women consumed more fluid (mean 2.424 L/day) than has been assumed in recent risk assessments for perchlorate. The data reported here indicate that lactating women may be exposed to perchlorate through dietary sources at markedly higher levels than estimated previously. Exposures to perchlorate from non-water sources may be higher than recent estimates, including those used to develop drinking water standards.
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Affiliation(s)
- Andrea B Kirk
- University of North Texas Health Sciences Center, USA
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25
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Fisher JW, Li S, Crofton K, Zoeller RT, McLanahan ED, Lumen A, Gilbert ME. Evaluation of Iodide Deficiency in the Lactating Rat and Pup Using a Biologically Based Dose-Response Model*. Toxicol Sci 2013; 132:75-86. [DOI: 10.1093/toxsci/kfs336] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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26
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Wu F, Zhou X, Zhang R, Pan M, Peng KL. The effects of ammonium perchlorate on thyroid homeostasis and thyroid-specific gene expression in rat. ENVIRONMENTAL TOXICOLOGY 2012; 27:445-452. [PMID: 20882593 DOI: 10.1002/tox.20655] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 08/02/2010] [Accepted: 08/09/2010] [Indexed: 05/29/2023]
Abstract
Perchlorate, a kind of inorganic chemical, is mainly used in defense industry and widely used in other civilian areas. It was well known that perchlorate exerts its thyrotoxicant effect on thyroid homeostasis via competitive inhibition of iodide uptake. However, some details of mechanism by which perchlorate disturb thyroid homeostasis are unknown and remain to be elucidated. The present study aimed to investigate if iodide insufficiency in the thyroid is the main mechanism by which perchlorate exerts its effect on the thyroid gland. We highlighted and measured the gene expression of NIS, Tg, and TPO which involved in thyroid hormone biosynthesis. Thyroid effects of perchlorate were identified by assessing different responses of these genes at the treatments of perchlorate and iodine deficiency. The results indicated that high dose perchlorate (520 mg kg(-1) b.wt.) can induce a significant decrease in body weight and cause hypertrophy of thyroid gland, with a decreased level of FT3, FT4 and a remarkable increased level of TSH. In addition, the significant decreased gene expression of Thyroglobulin (Tg) and thyroperoxidase (TPO) were both observed at the treatment of high dose perchlorate. These results suggested that perchlorate can suppress gene expression of Tg and TPO which directly involved in biosynthesis of thyroid hormones, and may therefore aggravate the perturbation of thyroid homeostasis in addition to competitive inhibition of iodide uptake.
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Affiliation(s)
- Fenghong Wu
- Institute of Industrial Toxicology, Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People's Republic of China
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27
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Fisher J, Lumen A, Latendresse J, Mattie D. Extrapolation of hypothalamic-pituitary-thyroid axis perturbations and associated toxicity in rodents to humans: case study with perchlorate. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2012; 30:81-105. [PMID: 22458857 DOI: 10.1080/10590501.2012.653889] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Functional aspects of the Hypothalamic-Pituitary-Thyroid (HPT) axis in rats and humans are compared, exposing why extrapolation of toxicant-induced perturbations in the rat HPT axis to the human HPT axis cannot be accomplished using default risk assessment methodology. Computational tools, such as biologically based dose response models for the HPT axis, are recommended to perform complex animal to human extrapolations involving the HPT axis. Experimental and computational evidence are presented that suggest perchlorate acts directly on the thyroid gland in rats. The apparent escape from perchlorate-induced inhibition of thyroidal uptake of radioactive iodide in humans is discussed along with "rebound" or increased thyroidal uptake of radioactive iodide observed after discontinued clinical treatment with perchlorate.
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Affiliation(s)
- Jeffrey Fisher
- Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079, USA.
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28
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Campbell JL, Clewell RA, Gentry PR, Andersen ME, Clewell HJ. Physiologically based pharmacokinetic/toxicokinetic modeling. Methods Mol Biol 2012; 929:439-499. [PMID: 23007440 DOI: 10.1007/978-1-62703-050-2_18] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Physiologically based pharmacokinetic (PBPK) models differ from conventional compartmental pharmacokinetic models in that they are based to a large extent on the actual physiology of the organism. The application of pharmacokinetics to toxicology or risk assessment requires that the toxic effects in a particular tissue are related in some way to the concentration time course of an active form of the substance in that tissue. The motivation for applying pharmacokinetics is the expectation that the observed effects of a chemical will be more simply and directly related to a measure of target tissue exposure than to a measure of administered dose. The goal of this work is to provide the reader with an understanding of PBPK modeling and its utility as well as the procedures used in the development and implementation of a model to chemical safety assessment using the styrene PBPK model as an example.
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Affiliation(s)
- Jerry L Campbell
- The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
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29
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McDougal JN, Jones KL, Fatuyi B, Gray KJ, Blount BC, Valentin-Blasini L, Fisher JW. The effects of perchlorate on thyroidal gene expression are different from the effects of iodide deficiency. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2011; 74:917-926. [PMID: 21623536 DOI: 10.1080/15287394.2011.573740] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Perchlorate (ClO₄⁻), which is a ubiquitous and persistent ion, competitively interferes with iodide (I) accumulation in the thyroid, producing I deficiency (ID), which may result in reduced thyroid hormone synthesis and secretion. Human studies suggest that ClO₄⁻ presents little risk in healthy individuals; however, the precautionary principle demands that the sensitive populations of ID adults and mothers require extra consideration. In an attempt to determine whether the effects on gene expression were similar, the thyroidal effects of ClO₄⁻ (10 mg/kg) treatment for 14 d in drinking water were compared with those produced by 8 wk of ID in rats. The thyroids were collected (n = 3 each group) and total mRNA was analyzed using the Affymetrix Rat Genome 230 2.0 GeneChip. Changes in gene expression were compared with appropriate control groups. The twofold gene changes due to ID were compared with alterations due to ClO₄⁻ treatment. One hundred and eighty-nine transcripts were changed by the ID diet and 722 transcripts were altered by the ClO₄⁻ treatment. Thirty-four percent of the transcripts changed by the I-deficient diet were also altered by ClO₄⁻ and generally in the same direction. Three specific transporter genes, AQP1, NIS, and SLC22A3, were changed by both treatments, indicating that the membrane-specific changes were similar. Iodide deficiency primarily produced alterations in retinol and calcium signaling pathways and ClO₄⁻ primarily produced changes related to the accumulation of extracellular matrix proteins. This study provides evidence that ClO₄⁻, at least at this dose level, changes more genes and alters different genes compared to ID.
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Affiliation(s)
- James N McDougal
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA.
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Li W, Zha J, Yang L, Li Z, Wang Z. Regulation of iodothyronine deiodinases and sodium iodide symporter mRNA expression by perchlorate in larvae and adult Chinese rare minnow (Gobiocypris rarus). MARINE POLLUTION BULLETIN 2011; 63:350-5. [PMID: 21377174 DOI: 10.1016/j.marpolbul.2011.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 12/19/2010] [Accepted: 02/09/2011] [Indexed: 05/09/2023]
Abstract
Perchlorate is a widespread contaminant in the aquatic environment. In the present work, the expressions of deiodinase enzymes (d1, d2, and d3) and sodium iodide symporter (nis) genes were determined after larval and adult rare minnow (Gobiocypris rarus) exposed to 5 and 50 μg/L perchlorate for 21 days. The results showed that deflation of swim bladder development was observed in larvae at 50 μg/L perchlorate treatment. An up-regulation of the d2 and nis mRNA levels were observed in the larve and in brain of adults. Meanwhile the expressions of d3 mRNA levels were significantly down-regulated in the liver. These results indicate the changes in d2, nis, and d3 mRNA expression brings about increased outer-ring deiodination, idodine uptake, and a further decrease of inner-ring deiodination, respectively reflecting auto-regulation of hypothalamic-pituitary-thyroid (HPT) axis in adult after perchlorate exposure. The larval fish development could be affected by perchlorate at environmentally relevant concentrations.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
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Crump KS, Chen C, Chiu WA, Louis TA, Portier CJ, Subramaniam RP, White PD. What role for biologically based dose-response models in estimating low-dose risk? ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:585-8. [PMID: 20056564 PMCID: PMC2866670 DOI: 10.1289/ehp.0901249] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 01/04/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND Biologically based dose-response (BBDR) models can incorporate data on biological processes at the cellular and molecular level to link external exposure to an adverse effect. OBJECTIVES Our goal was to examine the utility of BBDR models in estimating low-dose risk. METHODS We reviewed the utility of BBDR models in risk assessment. RESULTS BBDR models have been used profitably to evaluate proposed mechanisms of toxicity and identify data gaps. However, these models have not improved the reliability of quantitative predictions of low-dose human risk. In this commentary we identify serious impediments to developing BBDR models for this purpose. BBDR models do not eliminate the need for empirical modeling of the relationship between dose and effect, but only move it from the whole organism to a lower level of biological organization. However, in doing this, BBDR models introduce significant new sources of uncertainty. Quantitative inferences are limited by inter- and intraindividual heterogeneity that cannot be eliminated with available or reasonably anticipated experimental techniques. BBDR modeling does not avoid uncertainties in the mechanisms of toxicity relevant to low-level human exposures. Although implementation of BBDR models for low-dose risk estimation have thus far been limited mainly to cancer modeled using a two-stage clonal expansion framework, these problems are expected to be present in all attempts at BBDR modeling. CONCLUSIONS The problems discussed here appear so intractable that we conclude that BBDR models are unlikely to be fruitful in reducing uncertainty in quantitative estimates of human risk from low-level exposures in the foreseeable future. Use of in vitro data from recent advances in molecular toxicology in BBDR models is not likely to remove these problems and will introduce new issues regarding extrapolation of data from in vitro systems.
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Affiliation(s)
- Kenny S Crump
- Louisiana Tech University, Ruston, Louisiana 71272 , USA.
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Zewdie T, Smith CM, Hutcheson M, West CR. Basis of the Massachusetts reference dose and drinking water standard for perchlorate. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:42-48. [PMID: 20056583 PMCID: PMC2831965 DOI: 10.1289/ehp.0900635] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 01/30/2009] [Accepted: 07/13/2009] [Indexed: 05/28/2023]
Abstract
OBJECTIVE Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. DATA SOURCES MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. DATA SYNTHESIS We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 microg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 microg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. CONCLUSIONS Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed.
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Affiliation(s)
| | - C. Mark Smith
- Address correspondence to C.M. Smith, Massachusetts Department of Environmental Protection, Office of Research and Standards, 1 Winter St., Boston, MA 02108 USA. Telephone: (617) 292-5509. Fax: (617) 556-1006. E-mail:
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Kucharzyk KH, Crawford RL, Cosens B, Hess TF. Development of drinking water standards for perchlorate in the United States. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2009; 91:303-310. [PMID: 19850401 DOI: 10.1016/j.jenvman.2009.09.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/12/2009] [Accepted: 09/21/2009] [Indexed: 05/28/2023]
Abstract
Perchlorate, an anion that originates as a contaminant in ground and surface waters, is both naturally occurring and manmade. Because of its toxicity, there has been increased interest in setting drinking water safety standards and in health effects when perchlorate is present at low (parts per billion (ppb)) levels. In January 2009, the EPA issued a heath advisory to assist state and local officials in addressing local contamination of perchlorate in drinking water. The interim health advisory level of 15 micrograms per liter (microg/L), or ppb, is based on the reference dose recommended by the National Research Council (NRC) of the National Academy of Sciences (NAS). This paper describes scope and extent of contaminant issues and a legal process of setting standards for perchlorate concentration in drinking water in the United States of America.
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Affiliation(s)
- Katarzyna H Kucharzyk
- Environmental Biotechnology Institute, Environmental Science Program, University of Idaho, Moscow, ID 83844, USA.
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