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Qin G, Jia R, Xue J, Chen L, Li Y, Luo W, Wu X, An T, Fang Z. New Perspectives on the Risks of Hydroxylated Polychlorinated Biphenyl (OH-PCB) Exposure: Intestinal Flora α-Glucosidase Inhibition. TOXICS 2024; 12:237. [PMID: 38668460 PMCID: PMC11053903 DOI: 10.3390/toxics12040237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/14/2024] [Accepted: 03/19/2024] [Indexed: 04/29/2024]
Abstract
Polychlorinated biphenyls (PCBs) are a group of colorless and odorless environmental pollutants with a wide range of toxic effects. Some PCBs, especially less chlorinated ones, will rapidly undergo phase I metabolism after entering the body, and hydroxylated polychlorinated biphenyls (OH-PCBs) are the main metabolites of PCBs. Intestinal flora α-glucosidase is a common carbohydrate-active enzyme which is ubiquitous in human intestinal flora. It can convert complex dietary polysaccharides into monosaccharides, assisting the body in degrading complex carbohydrates and providing energy for the survival and growth of bacterial flora. The present study aims to investigate the inhibition of the activity of intestinal flora α-glucosidase by OH-PCBs. 4-Nitrophenyl-α-D-glucopyranoside (PNPG) was used as a probe substrate for α-glucosidase, and in vitro incubation experiments were conducted to study the inhibition of 26 representative OH-PCBs on α-glucosidase. Preliminary screening of in vitro incubation was performed with 100 μM of OH-PCBs. The results showed that 26 OH-PCBs generally exhibited strong inhibition of α-glucosidase. The concentration-dependent inhibition and half inhibition concentrations (IC50s) of OH-PCBs on α-glucosidase were determined. 4'-OH-PCB 86 and 4'-OH-PCB 106 were chosen as representative OH-PCBs, and the inhibition kinetic parameters (Kis) of inhibitors for α-glucosidase were determined. The inhibition kinetic parameters (Kis) of 4'-OH-PCB 86 and 4'-OH-PCB 106 for α-glucosidase are 1.007 μM and 0.538 μM, respectively. The silico docking method was used to further analyze the interaction mechanism between OH-PCBs and α-glucosidase. All these results will help us to understand the risks of OH-PCB exposure from a new perspective.
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Affiliation(s)
- Guoqiang Qin
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Ruoyong Jia
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Juntang Xue
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Li Chen
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Yang Li
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Weiming Luo
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Xiaomin Wu
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin 300070, China
- National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 100050, China
| | - Tianfeng An
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
| | - Zhongze Fang
- Department of Toxicology and Health Inspection and Quarantine, School of Public Health, Tianjin Medical University, Tianjin 300070, China
- Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin 300070, China
- National Demonstration Center for Experimental Preventive Medicine Education, Tianjin Medical University, Tianjin 300070, China
- Tianjin Center for International Collaborative Research in Environment, Nutrition and Public Health, Tianjin 300070, China
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Tang N, Fan P, Chen L, Yu X, Wang W, Wang W, Ouyang F. The Effect of Early Life Exposure to Triclosan on Thyroid Follicles and Hormone Levels in Zebrafish. Front Endocrinol (Lausanne) 2022; 13:850231. [PMID: 35721760 PMCID: PMC9203717 DOI: 10.3389/fendo.2022.850231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/02/2022] [Indexed: 11/24/2022] Open
Abstract
Triclosan (TCS) is an antimicrobial chemical widely used in personal care products. Most of the TCS component is discharged and enters the aquatic ecosystem after usage. TCS has a similar structure as thyroid hormones that are synthesized by thyroid follicular epithelial cells, thus TCS has a potential endocrine disrupting effect. It is still not clear how the different levels of the environmental TCS would affect early development in vivo. This study examines the effects of TCS on thyroid hormone secretion and the early development of zebrafish. The fertilized zebrafish eggs were exposed to TCS at 0 (control), 3, 30, 100, 300, and 900 ng/mL, and the hatching rate and the larvae mortality were inspected within the first 14 days. The total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), and free thyroxine (FT4) were measured at 7, 14, and 120 days post-fertilization (dpf). The histopathological examinations of thyroid follicles were conducted at 120 dpf. TCS exposure at 30-300 ng/mL reduced the hatching rate of larvae to 34.5% to 28.2 % in the first 48 hours and 93.8 .7 % to 86.8 % at 72 h. Extremely high TCS exposure (900 ng/mL) strongly inhibited the hatching rate, and all the larvae died within 1 day. Exposure to TCS from 3 to 300 ng/mL reduced the thyroid hormones production. The mean TT3 and FT3 levels of zebrafish decreased in 300 ng/mL TCS at 14 dpf (300 ng/mL TCS vs. control : TT3 , 0.19 ± 0.08 vs. 0.39 ± 0.06; FT3, 19.21 ± 3.13 vs. 28.53 ± 1.98 pg/mg), and the FT4 decreased at 120 dpf ( 0.09 ± 0.04 vs. 0.20 ± 0.14 pg/mg). At 120 dpf , in the 300 ng/mL TCS exposure group, the nuclear area and the height of thyroid follicular epithelial cells became greater, and the follicle cell layer got thicker. This happened along with follicle hyperplasia, nuclear hypertrophy, and angiogenesis in the thyroid. Our study demonstrated that early life exposure to high TCS levels reduces the rate and speed of embryos hatching, and induces the histopathological change of thyroid follicle, and decreases the TT3, FT3, and FT4 production in zebrafish.
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Affiliation(s)
- Ning Tang
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Pianpian Fan
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Chen
- Guangxi Key Laboratory of Tumor Immunology and Microenvironmental Regulation, Guilin Medical University, Guilin, China
| | - Xiaogang Yu
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Wang
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiye Wang
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fengxiu Ouyang
- Ministry of Education and Shanghai Key Laboratory of Children’s Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- *Correspondence: Fengxiu Ouyang, ;
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Behnisch PA, Besselink H, Weber R, Willand W, Huang J, Brouwer A. Developing potency factors for thyroid hormone disruption by PFASs using TTR-TRβ CALUX® bioassay and assessment of PFASs mixtures in technical products. ENVIRONMENT INTERNATIONAL 2021; 157:106791. [PMID: 34364217 DOI: 10.1016/j.envint.2021.106791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/05/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Over the last decade, per- and polyfluoroalkyl substances (PFASs) have become one of the most heavily investigated persistent organohalogen compound class of environmental concern. However, knowledge about their toxicology is still scarce, although PFASs as individual compounds and their industrial mixtures were shown to exert effects on the thyroid hormone system. METHODS In vitro toxicity potency factors were established for thyroid hormone transport disruption potential using the novel TTR-TRβ CALUX® bioassay for major PFASs. We assessed technical PFASs mixtures, including aqueous film-forming foam (AFFF) surfactants and chromium mist suppressants (CMS) applications with and without total oxidizable precursor (TOP) by TTR-TRβ CALUX® assay for their thyroid hormone transport disrupting potential. RESULTS All PFASs listed in the German guideline for drinking water (German Environment Agency, 2017) affected the T4 binding to TTR, an important plasma thyroid hormone transport protein. For all tested PFASs, potency factors based on PC80 values relative to PFOA could be obtained and ranged between PFBA (0.0018) and PFOS (2.0). Applying in vitro potency factors obtained from the present in vitro TTR-TRβ CALUX® assay study and recently reported in vivo potency factors (Zeilmaker et al., 2018; Bil et al., 2021) on the above-mentioned German guideline for PFAS in drinking water, showed that the cumulative effect-based trigger values (in vivo and in vitro) are comparable (3.0 vs. 2.9 to 4.6 μg PFOA-EQ/l). Additionally, AFFF surfactants and CMS with and without TOP assay were tested. Highest activities were found in the older AFFF surfactants (2013/2014) due to higher PFOS/PFOA levels, which were already substituted with 6:2 FTS in 2019, resulting in much lower PFOA-EQ levels. As expected also the PFOA-EQ levels increased in the samples with TOP treatment compared to the original AFFF surfactants and CMS as confirmed here by biological and chemical PFOA-equivalents (PFOA-EQ) analysis. Additionally, CMS (which have been used in the electroplating chromium industry since the 1950s) as well as PFOS-free, but not PFAS-free fume suppressants (such as Fumetrol® 21) have been tested in the TTR-TRβ CALUX® assay and showed much lower activity levels then the AFFFs, confirmed by the similar potency determination based on chemical PFASs analysis followed by transformation to PFOA-EQ for comparison. The potency factor of 6:2 FTS, which is the main substitute for PFOS in CMS, indicates that it is approximately 100-times less potent as a thyroid hormone disruptor as compared to PFOS. CONCLUSION Potency factors based on PC80 values from TTR-TRβ CALUX® relative to PFOA have been developed for major PFASs. In AFFF surfactants and CMS a trend of higher activities with higher amounts of PFOS and PFOA have been found. PFOA and PFOS showed high responses in the TTR-TRβ CALUX® assay and had the largest contributions to the PFOA-EQs in the AFFF surfactants and CMS applications. Using potency factors as determined in the TTR-TRβ CALUX® to convert PFASs assessed by chemical analysis to PFOA-EQ led to comparable results as compared to the results from PFASs measured directly by the TTR-TRβ CALUX® assay. This study supports the claim that semiquantitative effect- and group-based in vitro CALUX bioanalysis tools can be applied effectively to assess industrial products containing complex mixtures with PFAS compounds for which no instrumental analysis are established, and for many compounds where in vitro toxicity data are not yet available.
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Affiliation(s)
- Peter A Behnisch
- BioDetection Systems B.V. (BDS), Science Park 406, 1098 XH Amsterdam, the Netherlands
| | - Harrie Besselink
- BioDetection Systems B.V. (BDS), Science Park 406, 1098 XH Amsterdam, the Netherlands
| | - Roland Weber
- POPs Environmental Consulting, Lindenfirststrasse 23, 73527 Schwäbisch Gmünd, Germany
| | - Wolfram Willand
- IUW International Consultant on Integrated Environmental Protection and POPs, Hochfirstweg 12, 79853 Lenzkirch, Germany
| | - Jun Huang
- State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control (BKLEOC), Beijing Laboratory for Environmental Frontier Technologies (BLEFT), School of Environment, Tsinghua University, Beijing 100084, China
| | - Abraham Brouwer
- BioDetection Systems B.V. (BDS), Science Park 406, 1098 XH Amsterdam, the Netherlands; VU University Amsterdam, Faculty of Sciences, Department of Animal Ecology, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.
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Perinatal effects of persistent organic pollutants on thyroid hormone concentration in placenta and breastmilk. Mol Aspects Med 2021; 87:100988. [PMID: 34238594 DOI: 10.1016/j.mam.2021.100988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 06/08/2021] [Indexed: 12/18/2022]
Abstract
Thyroid hormones (TH) are known to play a critical role in regulating many biological processes including growth and development, energy homeostasis, thermogenesis, lipolysis and metabolism of cholesterol. Severe TH deficiency especially during fetal development results in cretinism, but can also lead to an imbalance in metabolism with, among others, an alteration in body weight composition. Over the past two decades, increasing evidence has shown that certain persistent organic pollutants (POP) can interfere with the endocrine system. These POP referred to as "endocrine disrupting chemicals" are widely present in the environment and populations are exposed globally. Moreover, epidemiological studies have shown that a particularly sensitive period is the pre- and postnatal time. Indeed, perinatal exposure to such chemicals could lead to the onset diseases in later life. It is known, that, maternal thyroid hormones are transported by the placenta to the fetus from 6 weeks of gestation and it seems that during the first trimester, and part of the second, the fetus is entirely dependent on maternal TH supply for its development. Interferences in the TH-network as a consequence of the exposure to such pollutants could cause variations in TH concentration. Only small changes in maternal thyroid hormone levels in early stages of pregnancy can influence fetal neurological and cardiovascular development, as well as according to recent studies, have effect on childhood body composition. With this review, we will report the most recent and important studies concerning the association between thyroid hormone concentration and POP levels measured during the perinatal period. We will mostly focus on the data recently reported on placenta and breastmilk as main sources for understanding the potential consequences of exposure. The possible link between exposure to pollutants, TH dysregulation and possible adverse outcome will also be briefly discussed. From our literature search, several studies support the hypothesis that pre- and postnatal exposure to different pollutants might play a role in causing variation in thyroid hormone concentration. However, few research papers have so far studied the relationship linking exposure to pollutants, TH concentration and possible health consequences. Therefore, this review highlights the need for further research in this direction.
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A review of species differences in the control of, and response to, chemical-induced thyroid hormone perturbations leading to thyroid cancer. Arch Toxicol 2021; 95:807-836. [PMID: 33398420 DOI: 10.1007/s00204-020-02961-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 11/26/2020] [Indexed: 12/13/2022]
Abstract
This review summarises the current state of knowledge regarding the physiology and control of production of thyroid hormones, the effects of chemicals in perturbing their synthesis and release that result in thyroid cancer. It does not consider the potential neurodevelopmental consequences of low thyroid hormones. There are a number of known molecular initiating events (MIEs) that affect thyroid hormone synthesis in mammals and many chemicals are able to activate multiple MIEs simultaneously. AOP analysis of chemical-induced thyroid cancer in rodents has defined the key events that predispose to the development of rodent cancer and many of these will operate in humans under appropriate conditions, if they were exposed to high enough concentrations of the affecting chemicals. There are conditions however that, at the very least, would indicate significant quantitative differences in the sensitivity of humans to these effects, with rodents being considerably more sensitive to thyroid effects by virtue of differences in the biology, transport and control of thyroid hormones in these species as opposed to humans where turnover is appreciably lower and where serum transport of T4/T3 is different to that operating in rodents. There is heated debate around claimed qualitative differences between the rodent and human thyroid physiology, and significant reservations, both scientific and regulatory, still exist in terms of the potential neurodevelopmental consequences of low thyroid hormone levels at critical windows of time. In contrast, the situation for the chemical induction of thyroid cancer, through effects on thyroid hormone production and release, is less ambiguous with both theoretical, and actual data, showing clear dose-related thresholds for the key events predisposing to chemically induced thyroid cancer in rodents. In addition, qualitative differences in transport, and quantitative differences in half life, catabolism and turnover of thyroid hormones, exist that would not operate under normal situations in humans.
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Marsan ES, Bayse CA. Halogen Bonding Interactions of Polychlorinated Biphenyls and the Potential for Thyroid Disruption. Chemistry 2020; 26:5200-5207. [PMID: 31849117 PMCID: PMC8812442 DOI: 10.1002/chem.201903904] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/13/2019] [Indexed: 11/21/2023]
Abstract
Polychlorinated biphenyl (PCB) flame retardants are persistent pollutants and inhibit neurodevelopment, particularly in the early stages of life. Halogen bonding (XB) to the iodothyronine deiodinases (Dio) that modulate thyroid hormones (THs) is a potential mechanism for endocrine disruption. Cl⋅⋅⋅Se XB interactions of PCBs with SeMe- , a small model of the Dio active site selenocysteine, are compared with previous results on polybrominated diphenylethers (PBDEs) and THs using density functional theory. PCBs generally display weaker XB interactions compared to PBDEs and THs, consistent with the dependence of XB strength on the size of the halogen (I>Br>Cl). PCBs also do not meet a proposed energy threshold for substrates to undergo dehalogenation, suggesting they may behave as competitive inhibitors of Dio in addition to other mechanisms of endocrine disruption. XB interactions in PCBs are position-dependent, with ortho interactions slightly more favorable than meta and para interactions, suggesting that PCBs may have a greater effect on certain classes of Dio. Flexibility of PCBs around the biphenyl C-C bond is limited by ortho substitutions relative to the biphenyl linkage, which may contribute to the ability to inhibit Dio and other TH-related proteins.
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Affiliation(s)
- Eric S Marsan
- Department of Chemistry and Biochemistry, Old Dominion University, 1 Old Dominion University, Norfolk, VA, 23529, USA
| | - Craig A Bayse
- Department of Chemistry and Biochemistry, Old Dominion University, 1 Old Dominion University, Norfolk, VA, 23529, USA
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Saktrakulkla P, Dhakal RC, Lehmler HJ, Hornbuckle KC. A semi-target analytical method for quantification of OH-PCBs in environmental samples. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020. [PMID: 31359319 DOI: 10.25820/036e-b439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) are oxidative metabolites of PCBs and residuals found in original Aroclors. OH-PCBs are known to play a role as genotoxicants, carcinogens, and hormone disruptors, and therefore it is important to quantify their presence in human tissues, organisms, and environmental matrices. Of 837 possible mono-OH-PCBs congeners, there are only ~ 70 methoxylated PCB (MeO-PCB) standards commercially available. Hence, a semi-target analytical method is needed for unknown OH-PCBs. The mass concentrations of these unknowns are sometimes determined by assuming the peak responses of other available compounds. This can bias the results due to the choices and availabilities of standards. To overcome this issue, we investigated the peak responses of all commercially available MeO-PCB standards with gas chromatography (GC) coupling with triple quadrupole (QqQ) mass spectrometry (MS) system, with positive electron impact (EI) ionization at 20-70 eV in selected ion monitoring (SIM) mode. We found correlations between the relative peak responses (RRFs) and the number of chlorine (#Cl) in the molecules of MeO-PCBs. Among the studied models, the quadratic regression of #Cl is the most suitable model in the RRF prediction (RRF = β1 × #Cl^2 + β0) when the peak responses are captured at 30 eV. We evaluated the performance of the model by analyzing 12 synthesized MeO-PCB standards and a PCB-contaminated sediment collected from a wastewater lagoon. We further demonstrate the utility of the model using a different chromatography column and GC-EI-MS system. We found the method and associated model to be sufficiently simple, accurate, and versatile for use in quantifying OH-PCBs in complex environmental samples.
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Affiliation(s)
- Panithi Saktrakulkla
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA
| | - Ram C Dhakal
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Keri C Hornbuckle
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA.
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Saktrakulkla P, Dhakal RC, Lehmler HJ, Hornbuckle KC. A semi-target analytical method for quantification of OH-PCBs in environmental samples. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:8859-8871. [PMID: 31359319 PMCID: PMC6986979 DOI: 10.1007/s11356-019-05775-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 06/17/2019] [Indexed: 04/16/2023]
Abstract
Hydroxylated polychlorinated biphenyls (OH-PCBs) are oxidative metabolites of PCBs and residuals found in original Aroclors. OH-PCBs are known to play a role as genotoxicants, carcinogens, and hormone disruptors, and therefore it is important to quantify their presence in human tissues, organisms, and environmental matrices. Of 837 possible mono-OH-PCBs congeners, there are only ~ 70 methoxylated PCB (MeO-PCB) standards commercially available. Hence, a semi-target analytical method is needed for unknown OH-PCBs. The mass concentrations of these unknowns are sometimes determined by assuming the peak responses of other available compounds. This can bias the results due to the choices and availabilities of standards. To overcome this issue, we investigated the peak responses of all commercially available MeO-PCB standards with gas chromatography (GC) coupling with triple quadrupole (QqQ) mass spectrometry (MS) system, with positive electron impact (EI) ionization at 20-70 eV in selected ion monitoring (SIM) mode. We found correlations between the relative peak responses (RRFs) and the number of chlorine (#Cl) in the molecules of MeO-PCBs. Among the studied models, the quadratic regression of #Cl is the most suitable model in the RRF prediction (RRF = β1 × #Cl^2 + β0) when the peak responses are captured at 30 eV. We evaluated the performance of the model by analyzing 12 synthesized MeO-PCB standards and a PCB-contaminated sediment collected from a wastewater lagoon. We further demonstrate the utility of the model using a different chromatography column and GC-EI-MS system. We found the method and associated model to be sufficiently simple, accurate, and versatile for use in quantifying OH-PCBs in complex environmental samples.
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Affiliation(s)
- Panithi Saktrakulkla
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA
| | - Ram C Dhakal
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, Iowa City, IA, 52242, USA
| | - Keri C Hornbuckle
- Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, IA, 52242, USA.
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Jin L, Yu H, Geng L, Ma G, Wei X. In silico study for inhibiting thyroid hormone sulfotransferase activity by halogenated phenolic chemicals. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:146-151. [PMID: 31082578 DOI: 10.1016/j.ecoenv.2019.05.014] [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: 03/27/2019] [Revised: 04/30/2019] [Accepted: 05/05/2019] [Indexed: 06/09/2023]
Abstract
Thyroid hormones (THs) are essential to proper growth and development of human bodies. Inhibiting the sulfation metabolism of THs has been demonstrated to be an important way for some environmental pollutants, such as halogenated phenolic compounds, to interfere THs homeostasis, thereby causing health problems. However, the important property characteristics that govern the sulfation inhibition of these chemicals are not well understood, and the experimental data on inhibition potential is limited. In this work, an in silico approach was developed to investigate the structure-activity relationship for their sulfotransferases (SULTs) inhibition. A series of quantum chemical descriptors that quantify the electronic and energy properties of 22 halogenated phenolic compounds have been calculated to establish a predictive model and analyzed their corresponding contributions to SULTs inhibition. Density functional theory (DFT) B3LYP/6-31G** has been employed to optimize molecular geometries to obtain a total of 15 descriptors for every compound. The implementation of linear regression shows three descriptors that represent molecular mass, positive charges on hydrogen atoms, and energy of frontier orbitals strongly correlate with SULTs inhibition potential. This indicates molecular size, hydrogen-bond strength, and nucleophilic-electrophilic reactivity may play important roles in SULTs inhibition. The derived regression model has good statistical performance (r2 = 0.84, rms = 0.35), and different validation strategies indicate it can serve as an efficient predictive tool for other chemicals in application domain but with no experimental data, consequently assisting in their THs sulfation inhibition and health risk assessment.
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Affiliation(s)
- Lingmin Jin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua, 321004, China
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua, 321004, China.
| | - Liming Geng
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua, 321004, China
| | - Guangcai Ma
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua, 321004, China
| | - Xiaoxuan Wei
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua, 321004, China
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Noyes PD, Friedman KP, Browne P, Haselman JT, Gilbert ME, Hornung MW, Barone S, Crofton KM, Laws SC, Stoker TE, Simmons SO, Tietge JE, Degitz SJ. Evaluating Chemicals for Thyroid Disruption: Opportunities and Challenges with in Vitro Testing and Adverse Outcome Pathway Approaches. ENVIRONMENTAL HEALTH PERSPECTIVES 2019; 127:95001. [PMID: 31487205 PMCID: PMC6791490 DOI: 10.1289/ehp5297] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/01/2019] [Accepted: 08/13/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Extensive clinical and experimental research documents the potential for chemical disruption of thyroid hormone (TH) signaling through multiple molecular targets. Perturbation of TH signaling can lead to abnormal brain development, cognitive impairments, and other adverse outcomes in humans and wildlife. To increase chemical safety screening efficiency and reduce vertebrate animal testing, in vitro assays that identify chemical interactions with molecular targets of the thyroid system have been developed and implemented. OBJECTIVES We present an adverse outcome pathway (AOP) network to link data derived from in vitro assays that measure chemical interactions with thyroid molecular targets to downstream events and adverse outcomes traditionally derived from in vivo testing. We examine the role of new in vitro technologies, in the context of the AOP network, in facilitating consideration of several important regulatory and biological challenges in characterizing chemicals that exert effects through a thyroid mechanism. DISCUSSION There is a substantial body of knowledge describing chemical effects on molecular and physiological regulation of TH signaling and associated adverse outcomes. Until recently, few alternative nonanimal assays were available to interrogate chemical effects on TH signaling. With the development of these new tools, screening large libraries of chemicals for interactions with molecular targets of the thyroid is now possible. Measuring early chemical interactions with targets in the thyroid pathway provides a means of linking adverse outcomes, which may be influenced by many biological processes, to a thyroid mechanism. However, the use of in vitro assays beyond chemical screening is complicated by continuing limits in our knowledge of TH signaling in important life stages and tissues, such as during fetal brain development. Nonetheless, the thyroid AOP network provides an ideal tool for defining causal linkages of a chemical exerting thyroid-dependent effects and identifying research needs to quantify these effects in support of regulatory decision making. https://doi.org/10.1289/EHP5297.
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Affiliation(s)
- Pamela D Noyes
- National Center for Environmental Assessment, Office of Research and Development (ORD), U.S. Environmental Protection Agency (EPA), Washington, DC, USA
| | - Katie Paul Friedman
- National Center for Computational Toxicology, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Patience Browne
- Environment Health and Safety Division, Environment Directorate, Organisation for Economic Co-operation and Development (OECD), Paris, France
| | - Jonathan T Haselman
- Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory (NHEERL), ORD, U.S. EPA, Duluth, Minnesota, USA
| | - Mary E Gilbert
- Toxicity Assessment Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Michael W Hornung
- Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory (NHEERL), ORD, U.S. EPA, Duluth, Minnesota, USA
| | - Stan Barone
- Office of Pollution Prevention and Toxics, Office of Chemical Safety and Pollution Prevention, U.S. EPA, Washington, DC, USA
| | - Kevin M Crofton
- National Center for Computational Toxicology, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Susan C Laws
- Toxicity Assessment Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Tammy E Stoker
- Toxicity Assessment Division, NHEERL, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Steven O Simmons
- National Center for Computational Toxicology, ORD, U.S. EPA, Research Triangle Park, North Carolina, USA
| | - Joseph E Tietge
- Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory (NHEERL), ORD, U.S. EPA, Duluth, Minnesota, USA
| | - Sigmund J Degitz
- Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory (NHEERL), ORD, U.S. EPA, Duluth, Minnesota, USA
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Zheng X, Yan Z, Liu P, Fan J, Wang S, Wang P, Zhang T. Research Progress on Toxic Effects and Water Quality Criteria of Triclosan. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2019; 102:731-740. [PMID: 30949737 DOI: 10.1007/s00128-019-02603-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Triclosan (TCS) is an effective broad-spectrum antimicrobial agent that is widely used in personal care products. It has been detected in different environmental media, and poses high potential ecological risk. In this article, we carried out a literature review of recent studies on the toxic effects of TCS from different aspects at the molecular, cell, tissue, organ, and individual level. TCS can exhibit acute toxicity to aquatic organisms, affect the normal expression and physiological function of enzymes and genes, and produce cytotoxicity. Many studies have demonstrated that TCS exerts significant endocrine-disrupting effects on organisms, interfering the normal physiological functions of the reproductive, thyroid, and nervous systems via related signaling pathways. Moreover, we reported current research on the water quality criteria of TCS and discuss possible future research directions.
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Affiliation(s)
- Xin Zheng
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Zhenguang Yan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
| | - Peiyuan Liu
- School of Life Sciences, Tianjin University, Tianjin, 300072, People's Republic of China
| | - Juntao Fan
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Shuping Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Pengyuan Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
| | - Tianxu Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China
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Shao Y, Chen Z, Hollert H, Zhou S, Deutschmann B, Seiler TB. Toxicity of 10 organic micropollutants and their mixture: Implications for aquatic risk assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 666:1273-1282. [PMID: 30970492 DOI: 10.1016/j.scitotenv.2019.02.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 02/03/2019] [Accepted: 02/03/2019] [Indexed: 05/06/2023]
Abstract
Micropollutants, as a serious water pollution issue, raise considerable toxicological concerns, particularly when present as components of complex mixtures. Due to the interactions of environmental pollution components (contaminant), the micropollutant problem is increasingly complex, thus, water quality of organic chemical contamination assessed substance-by-substance might lead to underestimation in aquatic environmental risk assessment. To assess the aquatic environmental risk of micropollutants mixture, a total of 10 organic micropollutants were selected and analysed by an approach of integration of literature data, laboratory experiments and prediction techniques. The experiment results showed that all 10 micropollutants were capable of causing toxicity in zebrafish embryos, aquatic invertebrates and algae with the LC50 (50% lethal concentration) values from 1.14 mg/L to 14.37 mg/L. Triclosan, carbamazepine, diazinon and diuron were the most hazardous compounds in the Danube River and the Rhine River. The artificial mixture presented a strong antagonistic relationship, which demonstrated an independent action (IA) model of the mixture. Based on the observed toxicity data, the risk quotients (RQs) of environmental mixtures of the Danube River and the Rhine River were extrapolated. It can be concluded that the micropollutant mixture may pose a potential risk for aquatic ecosystems with the present environmentally measured concentrations in the Danube River and Rhine River. Mixture risk assessment results suggested that the toxicity of studied chemicals might be induced by dissimilar actions, which is in agreement with the mixture toxicity prediction of the IA model. The observed findings could be useful to establish an overview of the pressures, vision, measures and expectations for hazardous substances pollution, which can help in making to informed decisions to reduce the concentration and bioactive fraction of pollutants.
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Affiliation(s)
- Ying Shao
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; Department of Cell Toxicology, UFZ - Helmholtz Centre for Environmental Research GmbH, Permoserstraße 15, 04318 Leipzig, Germany.
| | - Zhongli Chen
- Key Laboratory of the Three Gorges Reservoir Eco-environment, Chongqing University, 174 Shazheng Road, Shapingba, Chongqing 400045, China
| | - Henner Hollert
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; College of Resources and Environmental Science, Chongqing University, 174 Shazheng Road, Shapingba, Chongqing 400044, China; College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China
| | - Shangbo Zhou
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Björn Deutschmann
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Thomas-Benjamin Seiler
- Institute for Environmental Research (Biology V), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
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Itoh S, Baba T, Yuasa M, Miyashita C, Kobayashi S, Araki A, Sasaki S, Kajiwara J, Hori T, Todaka T, Fujikura K, Nakajima S, Kato S, Kishi R. Association of maternal serum concentration of hydroxylated polychlorinated biphenyls with maternal and neonatal thyroid hormones: The Hokkaido birth cohort study. ENVIRONMENTAL RESEARCH 2018; 167:583-590. [PMID: 30173115 DOI: 10.1016/j.envres.2018.08.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 05/18/2023]
Abstract
BACKGROUND Evidence on the toxicity of hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) for thyroid hormones (TH) is limited, and the underlying mechanism remains unknown. OBJECTIVES We aimed to investigate the effects of environmental prenatal exposure to OH-PCBs and maternal and neonatal TH levels, taking the maternal-fetal TH transfer into account. METHODS In this prospective birth cohort (the "Hokkaido study") we included 222 mother-neonate pairs. We measured five OH-PCB isomers in maternal serum samples either during pregnancy or within 5 days of delivery. Thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels were obtained from maternal blood samples at an early gestational stage (median; 11.1 weeks) and from heel prick samples of neonates between 4 and 7 days after birth. Multiple linear regression analysis and structural equation modeling (SEM) were performed to investigate the associations between maternal OH-PCB and maternal and neonatal TH levels. RESULTS Median concentration of ∑OH-PCBs was 25.37 pg/g wet weight. The predominant isomer was 4-OH-CB187, followed by 4-OH-CB146+3-OH-CB153. In the fully adjusted linear regression analysis, maternal ∑OH-PCBs was positively associated with maternal FT4, and 4-OH-CB187 was positively associated with both maternal and neonatal FT4 levels. Maternal OH-PCBs showed no significant association with TSH among mothers and neonates. Path analysis indicated the indirect pathway from 4-OH-CB187 exposure to increased neonatal FT4, via maternal THs and neonatal TSH. CONCLUSIONS These findings suggest that maternal exposure to OH-PCBs during pregnancy may increase both maternal and neonatal FT4 levels. Neonatal FT4 is presumed to be increased by prenatal 4-OH-CB187 indirectly, and this process may be mediated by maternal THs and neonatal TSH.
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Affiliation(s)
- Sachiko Itoh
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan
| | - Toshiaki Baba
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan; Department of Mental Health, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Motoyuki Yuasa
- Faculty of International Liberal Arts, Juntendo University, Tokyo, Japan
| | - Chihiro Miyashita
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan
| | - Sumitaka Kobayashi
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan
| | - Atsuko Araki
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan
| | - Seiko Sasaki
- Department of Public Health Sciences, Hokkaido University, Sapporo, Japan
| | - Jumboku Kajiwara
- Fukuoka Institute of Health and Environmental Sciences, Fukuoka, Japan
| | - Tsuguhide Hori
- Fukuoka Institute of Health and Environmental Sciences, Fukuoka, Japan
| | - Takashi Todaka
- Fukuoka Institute of Health and Environmental Sciences, Fukuoka, Japan
| | | | - Sonomi Nakajima
- Department of Occupational Therapy, School of Health Sciences, Sapporo Medical University, Sapporo, Japan
| | - Shizue Kato
- Department of Public Health Sciences, Hokkaido University, Sapporo, Japan
| | - Reiko Kishi
- Center for Environmental Health and Sciences, Hokkaido University, Sapporo, Japan.
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Dhakal K, Gadupudi GS, Lehmler HJ, Ludewig G, Duffel MW, Robertson LW. Sources and toxicities of phenolic polychlorinated biphenyls (OH-PCBs). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:16277-16290. [PMID: 28744683 PMCID: PMC5785587 DOI: 10.1007/s11356-017-9694-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 06/30/2017] [Indexed: 04/16/2023]
Abstract
Polychlorinated biphenyls (PCBs), a group of 209 congeners that differ in the number and position of chlorines on the biphenyl ring, are anthropogenic chemicals that belong to the persistent organic pollutants (POPs). For many years, PCBs have been a topic of interest because of their biomagnification in the food chain and their environmental persistence. PCBs with fewer chlorine atoms, however, are less persistent and more susceptible to metabolic attack, giving rise to chemicals characterized by the addition of one or more hydroxyl groups to the chlorinated biphenyl skeleton, collectively known as hydroxylated PCBs (OH-PCBs). In animals and plants, this biotransformation of PCBs to OH-PCBs is primarily carried out by cytochrome P-450-dependent monooxygenases. One of the reasons for infrequent detection of lower chlorinated PCBs in serum and other biological matrices is their shorter half-lives, and their metabolic transformation, resulting in OH-PCBs or their conjugates, such as sulfates and glucuronides, or macromolecule adducts. Recent biomonitoring studies have reported the presence of OH-PCBs in human serum. The occurrence of OH-PCBs, the size of this group (there are 837 mono-hydroxyl PCBs alone), and their wide spectra of physical characteristics (pKa's and log P's ranging over 5 to 6 orders of magnitude) give rise to a multiplicity of biological effects. Among those are bioactivation to electrophilic metabolites that can form covalent adducts with DNA and other macromolecules, interference with hormonal signaling, inhibition of enzymes that regulate cellular concentrations of active hormones, and interference with the transport of hormones. This new information creates an urgent need for a new perspective on these often overlooked metabolites.
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Affiliation(s)
- Kiran Dhakal
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Gopi S Gadupudi
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Hans-Joachim Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Gabriele Ludewig
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA
| | - Michael W Duffel
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA
- Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, IA, USA
| | - Larry W Robertson
- Interdisciplinary Graduate Program in Human Toxicology, Graduate College, The University of Iowa, Iowa City, IA, USA.
- Department of Occupational and Environmental Health, College of Public Health, The University of Iowa, 100 Oakdale Campus #219 IREH, Iowa City, IA, 52242-5000, USA.
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Dufour P, Pirard C, Charlier C. Determination of phenolic organohalogens in human serum from a Belgian population and assessment of parameters affecting the human contamination. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:1856-1866. [PMID: 28545212 DOI: 10.1016/j.scitotenv.2017.05.157] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/03/2017] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
Many in vitro or in vivo studies highlighted the potential deleterious effects of phenolic organohalogenated compounds (POHs) on the health, particularly on the thyroid system homeostasis, however few large scale human epidemiological studies have been carried out, especially in Europe. Further studies monitoring the human contamination by POHs, the sources of exposure and the influence of these compounds on thyroid health are still needed. Therefore we determined the concentrations of 16 POHs (pentachlorophenol (PCP), tetrabromobisphenol A (TBBPA), 4 bromophenols (BPs), 3 hydroxy-polybromodiphenylethers (OH-PBDEs) and 7 hydroxy-polychlorobiphenyls (OH-PCBs)) in serum from 274 people aged from 18 to 76years old living in Liege (Belgium) and the surrounding area. A questionnaire about their alimentary habits, life style and home environment was also administered to the volunteers. The predominant compound measured in the population was PCP (median concentration of 593.0pgmL-1). 4-OH-CB 107, 4-OH-CB 146 and 4-OH-CB 187 were detected in all samples and contributed for 75% of the sum of OH-PCBs (ΣOH-PCBs). The median measured in our population for ΣOH-PCBs was 143.7pgmL-1. TBBPA and 2,4,6-tribromophenol were detected in 31% and 63.8% of the samples respectively while the detection frequency observed for the other BPs and the OH-PBDEs was close to zero. We computed multivariate regression models in order to assess the influence of demographic and lifestyle parameters on the PCP and ΣOH-PCBs contamination levels. Significant correlation was found between the PCP concentration and sex, smoker status, sea fish consumption and level of education, although the model seemed to be a poor (R2=0.14) predictor of the PCP concentration. The model computed for ΣOH-PCBs was more explanatory (R2=0.61) and involved age, BMI and sea fish consumption. Finally, we assessed the parameters affecting the ΣOH-PCBs/ΣPCBs ratio. The model proposed involved age, BMI, smoker status and parent PCB level, and explained 41% of the variability of the ΣOH-PCBs/ΣPCBs ratio.
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Affiliation(s)
- Patrice Dufour
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg) CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg) CHU (B35), 4000, Liege, Belgium.
| | - Catherine Pirard
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg) CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg) CHU (B35), 4000, Liege, Belgium
| | - Corinne Charlier
- Laboratory of Clinical, Forensic and Environmental Toxicology, University of Liege (ULg) CHU (B35), 4000, Liege, Belgium; Center for Interdisciplinary Research on Medicines (C.I.R.M.), University of Liege (ULg) CHU (B35), 4000, Liege, Belgium
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17
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NTP Research Report on Biological Activity of Bisphenol A (BPA) Structural Analogues and Functional Alternatives. ACTA ACUST UNITED AC 2017. [DOI: 10.22427/ntp-rr-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Khan K, Roy K. Ecotoxicological modelling of cosmetics for aquatic organisms: A QSTR approach. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2017; 28:567-594. [PMID: 28780892 DOI: 10.1080/1062936x.2017.1352621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
In this study, externally validated quantitative structure-toxicity relationship (QSTR) models were developed for toxicity of cosmetic ingredients on three different ecotoxicologically relevant organisms, namely Pseudokirchneriella subcapitata, Daphnia magna and Pimephales promelas following the OECD guidelines. The final models were developed by partial least squares (PLS) regression technique, which is more robust than multiple linear regression. The obtained model for P. subcapitata shows that molecular size and complexity have significant impacts on the toxicity of cosmetics. In case of P. promelas and D. magna, we found that the largest contribution to the toxicity was shown by hydrophobicity and van der Waals surface area, respectively. All models were validated using both internal and test compounds employing multiple strategies. For each QSTR model, applicability domain studies were also performed using the "Distance to Model in X-space" method. A comparison was made with the ECOSAR predictions in order to prove the good predictive performances of our developed models. Finally, individual models were applied to predict toxicity for an external set of 596 personal care products having no experimental data for at least one of the endpoints, and the compounds were ranked based on a decreasing order of toxicity using a scaling approach.
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Affiliation(s)
- K Khan
- a Department of Pharmacoinformatics , National Institute of Pharmaceutical Educational and Research (NIPER) , Kolkata ; India
| | - K Roy
- b Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology , Jadavpur University , Kolkata , India
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Wang X, Ouyang F, Feng L, Wang X, Liu Z, Zhang J. Maternal Urinary Triclosan Concentration in Relation to Maternal and Neonatal Thyroid Hormone Levels: A Prospective Study. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:067017. [PMID: 28669941 PMCID: PMC5743753 DOI: 10.1289/ehp500] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/05/2016] [Accepted: 11/07/2016] [Indexed: 05/21/2023]
Abstract
BACKGROUND Triclosan (TCS) is a synthetic antibacterial chemical widely used in personal care products. TCS exposure has been associated with decreased thyroid hormone levels in animals, but human studies are scarce and controversial. OBJECTIVE We evaluated the association between maternal TCS exposure and thyroid hormone levels of mothers and newborns. METHODS TCS was measured by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in urine samples collected during gestational weeks 38.8±1.1 from 398 pregnant women in a prospective birth cohort enrolled in 2012-2013 in Shanghai, China. Maternal serum levels of free thyroxine (FT4), thyroid-stimulating hormone (TSH), and thyroid peroxidase antibody (TPOAb) were obtained from medical records. Cord blood levels of free triiodothyronine (FT3), FT4, TSH, and TPOAb were measured. Multiple linear and logistic regression models were used to examine the relationship between maternal urinary TCS and thyroid hormone levels. RESULTS TCS was detectable (≥0.1 ng/mL) in 98.24% of maternal urine samples with tertile of urinary TCS levels: low (>0.1-2.75 μg/g.Cr), medium (2.75–9.78 μg/g.Cr), and high (9.78–427.38 μg/g.Cr). With adjustment for potential confounders, cord blood log(FT3)pmol/L concentration was 0.11 lower in newborns of mothers with medium and high urinary TCS levels compared with those with low levels. At third trimester, the high TCS concentration was associated with 0.03 [95% confidence interval (CI) −0.08, −0.02] lower maternal serum log(FT4)pmol/L, whereas the medium TCS concentration was associated with 0.15 (95% CI: −0.28, −0.03) lower serum log(TSH)mIU/L with adjustment for covariates. CONCLUSIONS Our results suggest significant inverse associations between maternal urinary TCS and cord blood FT3 as well as maternal blood FT4 concentrations at third trimester. https://doi.org/10.1289/EHP500.
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Affiliation(s)
- Xu Wang
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fengxiu Ouyang
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liping Feng
- Department of Obstetrics and Gynecology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Xia Wang
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiwei Liu
- Department of Neonatology, International Peace Maternal and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zhang
- MOE-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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20
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Smythe TA, Butt CM, Stapleton HM, Pleskach K, Ratnayake G, Song CY, Riddell N, Konstantinov A, Tomy GT. Impacts of Unregulated Novel Brominated Flame Retardants on Human Liver Thyroid Deiodination and Sulfotransferation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7245-7253. [PMID: 28541672 DOI: 10.1021/acs.est.7b01143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The inhibitory effects of five novel brominated flame retardants, 1,2-bis(2,4,5-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP), and β-tetrabromoethylcyclohexane (β-TBECH), on thyroid hormone deiodinase (DIO) and sulfotransferase (SULT) activity were investigated using human in vitro liver microsomal and cytosolic bioassays. Enzymatic activity was measured by incubating active human liver subcellular fractions with thyroid hormones (T4 and rT3 separately) and measuring changes in thyroid hormone (T4, T3, rT3, and 3,3'-T2) concentrations. Only DBDPE showed inhibition of both outer and inner ring deiodination (O and IRD) of T3 and 3,3'-T2 formation from T4, respectively, with an estimated IC50 of 160 nM; no statistically significant inhibition of SULT activity was observed. ORD inhibition of 3,3'-T2 formation from rT3 was also observed (IC50 ∼ 100 nM). The kinetics of T4 O and IRD were also investigated, although a definitive mechanism could not be identified as the Michaelis-Menten parameters and maximal rate constants were not significantly different. Concentrations tested were intentionally above expected environmental levels, and this study suggests that these NBFRs are not potent human liver DIO and SULT inhibitors. To our knowledge, DBDPE is the first example of a nonhydroxylated contaminant inhibiting DIO activity, and further study of the mechanism of action is warranted.
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Affiliation(s)
- Tristan A Smythe
- Department of Chemistry, University of Manitoba , Winnipeg, MB R3T 2N2, Canada
| | - Craig M Butt
- Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States
| | - Heather M Stapleton
- Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States
| | - Kerri Pleskach
- Department of Fisheries and Oceans Canada, Freshwater Institute , Winnipeg, MB R3T 2N6, Canada
| | | | - Chae Yoon Song
- Department of Chemistry, McGill University , Montreal, QC H3A 0G4, Canada
| | - Nicole Riddell
- Wellington Laboratories, Inc. , 345 Southgate Drive, Guelph, ON N1G 3M5, Canada
| | - Alex Konstantinov
- Wellington Laboratories, Inc. , 345 Southgate Drive, Guelph, ON N1G 3M5, Canada
| | - Gregg T Tomy
- Department of Chemistry, University of Manitoba , Winnipeg, MB R3T 2N2, Canada
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21
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Fort DJ, Mathis MB, Pawlowski S, Wolf JC, Peter R, Champ S. Effect of triclosan on anuran development and growth in a larval amphibian growth and development assay. J Appl Toxicol 2017; 37:1182-1194. [DOI: 10.1002/jat.3474] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/09/2017] [Accepted: 03/09/2017] [Indexed: 01/02/2023]
Affiliation(s)
| | | | | | - Jeffrey C. Wolf
- Experimental Pathology Laboratories, Inc.; Sterling VA 20166 USA
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22
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Movasseghi AR, Rodríguez-Estival J, Smits JEG. Thyroid pathology in deer mice (Peromyscus maniculata) from a reclaimed mine site on the athabasca oil sands. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 222:42-49. [PMID: 28104343 DOI: 10.1016/j.envpol.2017.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/29/2016] [Accepted: 01/06/2017] [Indexed: 06/06/2023]
Abstract
Information on naturally occurring thyroid disease in wild animals in general and in small mammals specifically is extremely limited. In the present field-based work, we investigated the structure and function of thyroid glands of deer mice (Peromyscus maniculata) studied as sentinels of ecosystem sustainability on reclaimed areas post-mining on the oil sands of northeastern Alberta, because of their greater sensitivity to contaminants relative to meadow voles (Microtus pennsylvanicus) on the same sites. Extraction of bitumen in the oil sands of northeastern Alberta, results in the release of contaminants including polycyclic aromatic compounds (PACs), metals, and metalloids to the environment that have a measurable biological cost to wildlife living in the affected areas. In previous investigations, deer mice exposed to pollution at reclaimed areas showed compromised ability to regenerate glutathione indicating oxidative stress, together with decreased testicular mass and body condition during the breeding season. In the present study, thyroid glands from those deer mice from the reclaimed site had markedly increased follicular cell proliferation and decreased colloid compared to animals from the reference site. This pathology was positively associated with the greater oxidative stress in the deer mice. Thyroid hormones, both thyroxine and triiodothyronine, were also higher in animals with greater oxidative stress indicating increased metabolic demands from contaminant related subclinical toxicity. This work emphasizes the value of using a combination of endocrinological, histological and oxidative stress biomarkers to provide sensitive measures of contaminant exposure in small mammals on the oil sands.
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Affiliation(s)
- Ahmad R Movasseghi
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW Calgary, Alberta T2N 4Z6, Canada.
| | - Jaime Rodríguez-Estival
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW Calgary, Alberta T2N 4Z6, Canada.
| | - Judit E G Smits
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW Calgary, Alberta T2N 4Z6, Canada.
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Louis GW, Hallinger DR, Braxton MJ, Kamel A, Stoker TE. Effects of chronic exposure to triclosan on reproductive and thyroid endpoints in the adult Wistar female rat. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:236-249. [PMID: 28569618 PMCID: PMC5994608 DOI: 10.1080/15287394.2017.1287029] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Triclosan (TCS), an antibacterial, has been shown to be an endocrine disruptor in the rat. Previously, subchronic TCS treatment to female rats was found to advance puberty and potentiate the effect of ethinyl estradiol (EE) on uterine growth when EE and TCS were co-administered prior to weaning. In the pubertal study, a decrease in serum thyroxine (T4) concentrations with no significant change in serum thyroid-stimulating hormone (TSH) was also observed. The purpose of the present study was to further characterize the influence of TCS on the reproductive and thyroid axes of the female rat using a chronic exposure regimen. Female Wistar rats were exposed by oral gavage to vehicle control, EE (1 μg/kg), or TCS (2.35, 4.69, 9.375 or 37.5 mg/kg) for 8 months and estrous cyclicity monitored. Although a divergent pattern of reproductive senescence appeared to emerge from 5 to 11 months of age between controls and EE-treated females, no significant difference in cyclicity was noted between TCS-treated and control females. A higher % control females displayed persistent diestrus (PD) by the end of the study, whereas animals administered with positive control (EE) were predominately persistent estrus (PE). Thyroxine concentration was significantly decreased in TCS-administered 9.375 and 37.5 mg/kg groups, with no marked effects on TSH levels, thyroid tissue weight, or histology. Results demonstrate that a long-term exposure to TCS did not significantly alter estrous cyclicity or timing of reproductive senescence in females but suppressed T4 levels at a lower dose than previously observed.
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Affiliation(s)
- Gwendolyn W. Louis
- Endocrine Toxicology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. EPA, Research Triangle Park, NC, USA
- Oak Ridge Institute for Science and Education (ORISE), US Department of Energy, Oak Ridge, TN, USA
| | - Daniel R. Hallinger
- Endocrine Toxicology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. EPA, Research Triangle Park, NC, USA
| | - M. Janay Braxton
- Endocrine Toxicology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. EPA, Research Triangle Park, NC, USA
| | - Alaa Kamel
- Analytical Chemistry Branch, Biological and Economic Analysis Division, Office of Pesticide Programs, U.S. EPA, Fort Meade, MD, USA
| | - Tammy E. Stoker
- Endocrine Toxicology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. EPA, Research Triangle Park, NC, USA
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Soechitram SD, Berghuis SA, Visser TJ, Sauer PJJ. Polychlorinated biphenyl exposure and deiodinase activity in young infants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:1117-1124. [PMID: 27710904 DOI: 10.1016/j.scitotenv.2016.09.098] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/22/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Several studies have shown effects of polychlorinated biphenyls (PCBs) on serum thyroid hormone levels in pregnant woman and their infants, while other studies did not find such effects. How PCBs might affect thyroid hormone metabolism, is still unclear. Potential mechanisms are direct influence on the thyroid gland, binding to thyroid binding proteins, increased excretion or metabolism of thyroid hormones by deiodinases or sulfatases. It is also not well known whether the effect on thyroid hormone levels is caused by PCBs themselves, or by their hydroxylated metabolites (OH-PCBs). OBJECTIVE To determine the effects of perinatal exposure to PCBs and OH-PCBs on thyroid hormone levels in cord blood and in serum of newborn infants. METHODS In a Dutch cohort of 100 mother-infant pairs, exposed to background PCB levels, correlations were assessed between 10 PCBs and 6 OH-PCBs in maternal blood during pregnancy and serum thyroxine (T4), T4 sulfate (T4S), triiodothyronine (T3), reverse T3 (rT3), thyroid-stimulating hormone (TSH) and thyroxine-binding globulin (TBG) levels in cord blood and in serum of three- and 18-month-old infants. We corrected for age of the mother, gestational age, gender and type of feeding. RESULTS After correction, prenatal levels of three of 10 measured PCBs showed a positive correlation with cord serum T3, and four PCBs showed a negative correlation with cord serum rT3. After correction, two PCBs and the sum of the 10 measured PCBs were positively correlated with the cord serum T3/rT3 ratio, an indicator of deiodinase 3 activity. No correlations were found between PCBs and T4, TSH and TBG in cord blood. 4-OH-PCB-107 was correlated with T4 at 3months and T4, T4S and T3 at 18months. CONCLUSION Our results suggest that PCBs have a negative effect on deiodinase type 3 activity, as reflected by a positive correlation with the T3/rT3 ratio. We identified a potential mechanism by which PCBs may affect thyroid hormone metabolism during human development.
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Affiliation(s)
- Shalini D Soechitram
- Division of Neonatology, Department of Pediatrics, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Sietske A Berghuis
- Division of Neonatology, Department of Pediatrics, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Theo J Visser
- Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Pieter J J Sauer
- Division of Neonatology, Department of Pediatrics, Beatrix Children's Hospital, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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25
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Ruszkiewicz JA, Li S, Rodriguez MB, Aschner M. Is Triclosan a neurotoxic agent? JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2017; 20:104-117. [PMID: 28339349 DOI: 10.1080/10937404.2017.1281181] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Triclosan (TCS) is an antibacterial agent that has been used in many products since 1960s. Given its broad usage as an antiseptic TCS is present ubiquitously in the environment. Trace levels of TCS continue to be detected in many organisms, and it has been shown to be particularly toxic to aquatic species. The mechanisms underlying TCS-mediated toxicity include hormone dyshomeostasis, induction of oxidative stress, apoptosis and inflammation. Although TCS has been considered to be non-toxic to mammals, the adverse effects of continuous, long-term and low concentration exposure remain unknown. Epidemiological studies revealed that levels of TCS in human tissues, urine, plasma and breast milk correlate with the usage of this antimicrobial. This led to concerns regarding TCS safety and potential toxicity in humans, with special emphasis on early development. The Food and Drug Administration (FDA) recently issued a directive banning the use of TCS in consumer soaps, justifying the move attributed to data gaps on its effectiveness and safety, indicating the need for more studies addressing this chemical-mediated effects on various tissues including the central nervous system (CNS). The aim of this review was to (1) summarize the current findings on the neurotoxic effects of TCS and given the paucity of data, to (2) broaden the discussion to other effects of TCS, which might plausibly be related to neuronal functions.
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Affiliation(s)
- Joanna A Ruszkiewicz
- a Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , NY , United States
| | - Shaojun Li
- b Department of Toxicology, School of Public Health , Guangxi Medical University , Guangxi , China
| | - Maliya B Rodriguez
- a Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , NY , United States
| | - Michael Aschner
- a Department of Molecular Pharmacology , Albert Einstein College of Medicine , Bronx , NY , United States
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Grimm FA, Hu D, Kania-Korwel I, Lehmler HJ, Ludewig G, Hornbuckle KC, Duffel MW, Bergman A, Robertson LW. Metabolism and metabolites of polychlorinated biphenyls. Crit Rev Toxicol 2015; 45:245-72. [PMID: 25629923 PMCID: PMC4383295 DOI: 10.3109/10408444.2014.999365] [Citation(s) in RCA: 282] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/11/2014] [Indexed: 11/13/2022]
Abstract
Abstract The metabolism of polychlorinated biphenyls (PCBs) is complex and has an impact on toxicity, and thereby on the assessment of PCB risks. A large number of reactive and stable metabolites are formed in the processes of biotransformation in biota in general, and in humans in particular. The aim of this document is to provide an overview of PCB metabolism, and to identify the metabolites of concern and their occurrence. Emphasis is given to mammalian metabolism of PCBs and their hydroxyl, methylsulfonyl, and sulfated metabolites, especially those that persist in human blood. Potential intracellular targets and health risks are also discussed.
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Affiliation(s)
- FA Grimm
- Interdisciplinary Graduate Program in Human Toxicology, Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa
| | - D Hu
- Department of Civil and Environmental Engineering, University of Iowa
| | - I Kania-Korwel
- Department of Occupational & Environmental Health, University of Iowa
| | - HJ Lehmler
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
| | - G Ludewig
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
| | - KC Hornbuckle
- Interdisciplinary Graduate Program in Human Toxicology, Department of Civil and Environmental Engineering, University of Iowa
| | - MW Duffel
- Interdisciplinary Graduate Program in Human Toxicology, Department of Pharmaceutical Sciences & Experimental Therapeutics, University of Iowa
| | - A Bergman
- Swedish Toxicology Sciences Research Center (SWETOX), Forskargatan 20, SE-151 36 Södertälje, SWEDEN
| | - LW Robertson
- Interdisciplinary Graduate Program in Human Toxicology, Department of Occupational & Environmental Health, University of Iowa
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Geens T, Dirtu AC, Dirinck E, Malarvannan G, Van Gaal L, Jorens PG, Covaci A. Daily intake of bisphenol A and triclosan and their association with anthropometric data, thyroid hormones and weight loss in overweight and obese individuals. ENVIRONMENT INTERNATIONAL 2015; 76:98-105. [PMID: 25575039 DOI: 10.1016/j.envint.2014.12.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 11/05/2014] [Accepted: 12/08/2014] [Indexed: 05/25/2023]
Abstract
Bisphenol A (BPA) and triclosan (TCS) were determined in urine of Belgian overweight and obese (n=151) and lean (n=43) individuals. After the first urine collection (0M), obese patients started a diet program or have undergone bariatric surgery. Hereafter, three additional urine samples from obese patients were collected after 3 (3M), 6 (6M) and 12 (12M) months. Both compounds were detected in >99% of the samples. BPA had median concentrations of 1.7 and 1.2ng/mL in obese and lean groups, respectively, while TCS had median concentrations of 1.5 and 0.9ng/mL in the obese and lean groups, respectively. The obese group had higher urinary concentrations (ng/mL) of BPA (p<0.5), while no significant differences were found for TCS between the obese and lean groups. No time trends between the different collection moments were observed. The BPA concentrations in the obese group were negatively associated with age, while no gender difference or relationship with body mass index was observed. For TCS, no relationships with gender, BMI, or age were found. The temporal variability of BPA and TCS was assessed with calculation of the intraclass correlation coefficient, Spearman rank correlation coefficients, and surrogate category analysis. We observed evidence that single spot urine samples might be predictive of exposure over a longer period of time. Dietary intakes of BPA and TCS did not differ significantly among the time points considered after obese individuals started losing weight (6 and 12months). Multiple linear regression analyses after adjusting for age and weight loss revealed negative associations between urinary TCS and serum FT4 in the 0M and 3M female obese individuals and positive associations between urinary BPA and serum TSH in the lean group.
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Affiliation(s)
- Tinne Geens
- Toxicological Centre, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
| | - Alin C Dirtu
- Toxicological Centre, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium
| | - Eveline Dirinck
- Department of Endocrinology, Diabetology and Metabolic Disease, University of Antwerp and Antwerp University Hospital, 2630 Edegem, Antwerp, Belgium
| | | | - Luc Van Gaal
- Department of Endocrinology, Diabetology and Metabolic Disease, University of Antwerp and Antwerp University Hospital, 2630 Edegem, Antwerp, Belgium
| | - Philippe G Jorens
- Department of Clinical Pharmacology, University of Antwerp and Antwerp University Hospital, 2630 Edegem, Antwerp, Belgium
| | - Adrian Covaci
- Toxicological Centre, University of Antwerp, 2610 Wilrijk, Antwerp, Belgium.
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Vélez MP, Arbuckle TE, Fraser WD. Female exposure to phenols and phthalates and time to pregnancy: the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. Fertil Steril 2015; 103:1011-1020.e2. [PMID: 25681860 DOI: 10.1016/j.fertnstert.2015.01.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/02/2015] [Accepted: 01/02/2015] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To assess the potential effect of bisphenol A (BPA), triclosan (TCS), and phthalates on women's fecundity, as measured by time to pregnancy (TTP). DESIGN Pregnancy-based retrospective TTP study. SETTING Not applicable. PATIENT(S) A total of 2,001 women during the first trimester of pregnancy recruited between 2008 and 2011 (the Maternal-Infant Research on Environmental Chemicals (MIREC) Study), with 1,742 women included in the BPA analysis, 1,699 in the TCS analysis, and 1,597 in the phthalates analysis. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Fecundability odds ratios (FORs) estimated using the Cox model modified for discrete time data. RESULT(S) The BPA concentrations were not statistically significantly associated with diminished fecundity either in crude or adjusted models. Women in the highest quartile of TCS (>72 ng/mL) had evidence of decreased fecundity (FOR 0.84; 95% confidence interval, 0.72-0.97) compared with the three lower quartiles as the reference group. Exposure to phthalates was suggestive of a shorter TTP, as indicated by FORs greater than 1, although the 95% confidence interval always included 1. CONCLUSION(S) Elevated TCS exposure may be associated with diminished fecundity. BPA and phthalates showed no negative impact; on the contrary, some phthalates might be associated with a shorter time to pregnancy. A major limitation of the study was that only one measurement of exposure was available for each woman after conception. Further research is necessary to test these findings.
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Affiliation(s)
- Maria P Vélez
- Sainte-Justine University Hospital Research Center, University of Montreal, Montreal, Quebec, Canada.
| | - Tye E Arbuckle
- Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada
| | - William D Fraser
- Sainte-Justine University Hospital Research Center, University of Montreal, Montreal, Quebec, Canada
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29
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Louis C, Covaci A, Stas M, Crocker DE, Malarvannan G, Dirtu AC, Debier C. Bioaccumulation of hydroxylated polychlorinated biphenyls and pentachlorophenol in the serum of northern elephant seal pups (Mirounga angustirostris). ENVIRONMENTAL RESEARCH 2015; 136:441-448. [PMID: 25460666 DOI: 10.1016/j.envres.2014.08.040] [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: 07/14/2014] [Revised: 08/25/2014] [Accepted: 08/28/2014] [Indexed: 06/04/2023]
Abstract
Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were sampled at 1-, 4-, 7- and 10-week post-weaning. Concentrations of hydroxylated polychlorinated biphenyls (HO-PCBs) and their parent PCBs were measured in the serum of each individual. The ΣHO-PCB concentrations in the serum increased significantly between early and late fast (from 282 ± 20 to 529 ± 31 pg/mL). This increase might result from a mobilisation of HO-PCBs transferred from the mother during gestation and/or lactation and stored in the pup's liver. Food deprivation has been shown to exacerbate biotransformation capacities in mammals, birds and fish. The HO-penta-CBs was the predominant homologue group, followed by HO-hexa-CBs and HO-hepta-CBs. No preferential pathway for the metabolism of HO-PCBs (HO-direct insertion or NIH-shift of a chlorine atom) could be evidenced. The concentrations of pentachlorophenol (PCP) in the serum of weaned NES increased from 103 ± 7 pg/mL at early fast to 246 ± 41 pg/mL at late fast, which is within the range of PCP concentrations usually encountered in marine mammals.
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Affiliation(s)
- Caroline Louis
- Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium.
| | - Adrian Covaci
- Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Marie Stas
- Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, 1801 East Cotati Ave, Rohnert Park, CA 94928, USA
| | - Govindan Malarvannan
- Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Alin C Dirtu
- Department of Pharmaceutical Sciences, Toxicological Center, Campus Drie Eiken, Universiteit Antwerpen, Universiteitsplein 1, 2610 Wilrijk, Belgium; Department of Chemistry, "Al. I. Cuza" University of Iasi, 700506 Iasi, Romania
| | - Cathy Debier
- Institut des Sciences de la Vie, UCLouvain, Croix du Sud 2/L7.05.08, 1348 Louvain-la-Neuve, Belgium
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30
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Liu C, Ha M, Li L, Yang K. PCB153 and p,p'-DDE disorder thyroid hormones via thyroglobulin, deiodinase 2, transthyretin, hepatic enzymes and receptors. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:11361-11369. [PMID: 24878560 DOI: 10.1007/s11356-014-3093-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 05/23/2014] [Indexed: 06/03/2023]
Abstract
Polychlorinated biphenyls (PCBs) and DDT are widespread environmental persistent organic pollutants that have various adverse effects on reproduction, development and endocrine function. In order to elucidate effects of PCBs and DDT on thyroid hormone homeostasis, Sprague-Dawley rats were dosed with PCB153 and p,p'-DDE intraperitoneally (ip) for five consecutive days and sacrificed within 24 h after the last dose. Results indicated that after combined exposure to PCB153 and p,p'-DDE, total thyroxine , free thyroxine, total triiodothyronine, and thyroid-stimulating hormone in serum were decreased, whereas free triiodothyronine and thyrotropin-releasing hormone were not affected. Thyroglobulin and transthyretin levels in serum were significantly reduced. mRNA expression of deiodinases 2 (D2) was also suppressed, while D1 and D3 levels were not significantly influenced after combined exposure. PCB153 and p,p'-DDE induced hepatic enzymes, UDPGTs, CYP1A1, CYP2B1, and CYP3A1 mRNA expressions being significantly elevated. Moreover, TRα1, TRβ1, and TRHr expressions in the hypothalamus displayed increasing trends after combined exposure to PCB153 and p,p'-DDE. Taken together, observed results indicate that PCB153 and p,p'-DDE could disorder thyroid hormone homeostasis via thyroglobulin, deiodinase 2, transthyretin, hepatic enzymes, and hormone receptors.
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Affiliation(s)
- Changjiang Liu
- Key Lab of Birth Defects and Reproductive Health of National Health and Family Planning Commission, Chongqing Population and family planning Science and Technology Research Institute, Chongqing, 400020, People's Republic of China
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James MO, Ambadapadi S. Interactions of cytosolic sulfotransferases with xenobiotics. Drug Metab Rev 2014; 45:401-14. [PMID: 24188364 DOI: 10.3109/03602532.2013.835613] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Cytosolic sulfotransferases are a superfamily of enzymes that catalyze the transfer of the sulfonic group from 3'-phosphoadenosine-5'-phosphosulfate to hydroxy or amine groups in substrate molecules. The human cytosolic sulfotransferases that have been most studied, namely SULT1A1, SULT1A3, SULT1B1, SULT1E1 and SULT2A1, are expressed in different tissues of the body, including liver, intestine, adrenal, brain and skin. These sulfotransferases play important roles in the sulfonation of endogenous molecules such as steroid hormones and neurotransmitters, and in the elimination of xenobiotic molecules such as drugs, environmental chemicals and natural products. There is often overlapping substrate selectivity among the sulfotransferases, although one isoform may exhibit greater enzyme efficiency than other isoforms. Similarly, inhibitors or enhancers of one isoform often affect other isoforms, but typically with different potency. This means that if the activity of one form of sulfotransferase is altered (either inhibited or enhanced) by the presence of a xenobiotic, the sulfonation of endogenous and xenobiotic substrates for other isoforms may well be affected. There are more examples of inhibitors than enhancers of sulfonation. Modulators of sulfotransferase enzymes include natural products ingested as part of the human diet as well as environmental chemicals and drugs. This review will discuss recent work on such interactions.
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Affiliation(s)
- Margaret O James
- Department of Medicinal Chemistry, University of Florida, Gainesville , FL , USA
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Khraisheh M, Kim J, Campos L, Al-Muhtaseb AH, Al-Hawari A, Al Ghouti M, Walker GM. Removal of pharmaceutical and personal care products (PPCPs) pollutants from water by novel TiO2–Coconut Shell Powder (TCNSP) composite. J IND ENG CHEM 2014. [DOI: 10.1016/j.jiec.2013.06.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Freitas J, Miller N, Mengeling BJ, Xia M, Huang R, Houck K, Rietjens IMCM, Furlow JD, Murk AJ. Identification of thyroid hormone receptor active compounds using a quantitative high-throughput screening platform. Curr Chem Genom Transl Med 2014; 8:36-46. [PMID: 24772387 PMCID: PMC3999704 DOI: 10.2174/2213988501408010036] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 12/09/2013] [Accepted: 12/12/2013] [Indexed: 02/02/2023] Open
Abstract
To adapt the use of GH3.TRE-Luc reporter gene cell line for a quantitative high-throughput screening (qHTS)
platform, we miniaturized the reporter gene assay to a 1536-well plate format. 1280 chemicals from the Library of Pharmacologically
Active Compounds (LOPAC) and the National Toxicology Program (NTP) 1408 compound collection
were analyzed to identify potential thyroid hormone receptor (TR) agonists and antagonists. Of the 2688 compounds
tested, eight scored as potential TR agonists when the positive hit cut-off was defined at ≥10% efficacy, relative to maximal
triiodothyronine (T3) induction, and with only one of those compounds reaching ≥20% efficacy. One common class of
compounds positive in the agonist assays were retinoids such as all-trans retinoic acid, which are likely acting via the retinoid-X receptor, the heterodimer partner with the TR. Five potential TR antagonists were identified, including the antiallergy
drug tranilast and the anxiolytic drug SB 205384 but also some cytotoxic compounds like 5-fluorouracil. None of
the inactive compounds were structurally related to T3, nor had been reported elsewhere to be thyroid hormone disruptors,
so false negatives were not detected. None of the low potency (>100µM) TR agonists resembled T3 or T4, thus these may
not bind directly in the ligand-binding pocket of the receptor. For TR agonists, in the qHTS, a hit cut-off of ≥20% efficacy
at 100 µM may avoid identification of positives with low or no physiological relevance. The miniaturized GH3.TRE-Luc
assay offers a promising addition to the in vitro test battery for endocrine disruption, and given the low percentage of
compounds testing positive, its high-throughput nature is an important advantage for future toxicological screening.
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Affiliation(s)
- Jaime Freitas
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE Wageningen, The Netherlands ; Group of Cell Activation and Gene Expression, Institute for Molecular and Cellular Biology, University of Porto, Porto, Portugal
| | - Nicole Miller
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Brenda J Mengeling
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis 95616, USA
| | - Menghang Xia
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ruili Huang
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Keith Houck
- National Center for Computational Toxicology, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE Wageningen, The Netherlands
| | - J David Furlow
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis 95616, USA
| | - Albertinka J Murk
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE Wageningen, The Netherlands ; Subdepartment of Environmental Technology, Wageningen University, and Wageningen-IMARES, Axis Z (Building number 118), Room TT.1.100, Bornse Weilanden 96708, WG Wageningen, The Netherlands
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Shimizu R, Yamaguchi M, Uramaru N, Kuroki H, Ohta S, Kitamura S, Sugihara K. Structure–activity relationships of 44 halogenated compounds for iodotyrosine deiodinase-inhibitory activity. Toxicology 2013; 314:22-9. [DOI: 10.1016/j.tox.2013.08.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 08/19/2013] [Accepted: 08/26/2013] [Indexed: 10/26/2022]
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Butt CM, Stapleton HM. Inhibition of thyroid hormone sulfotransferase activity by brominated flame retardants and halogenated phenolics. Chem Res Toxicol 2013; 26:1692-702. [PMID: 24089703 DOI: 10.1021/tx400342k] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Many halogenated organic contaminants (HOCs) are considered endocrine disruptors and affect the hypothalamic-pituitary-thyroid axis, often by interfering with circulating levels of thyroid hormones (THs). We investigated one potential mechanism for TH disruption, inhibition of sulfotransferase activity. One of the primary roles of TH sulfation is to support the regulation of biologically active T3 through the formation of inactive THs. We investigated TH sulfotransferase inhibition by 14 hydroxylated polybrominated diphenyl ethers (OH BDEs), BDE 47, triclosan, and fluorinated, chlorinated, brominated, and iodinated analogues of 2,4,6-trihalogenated phenol and bisphenol A (BPA). A new mass spectrometry-based method was also developed to measure the formation rates of 3,3'-T2 sulfate (3,3'-T2S). Using pooled human liver cytosol, we investigated the influence of these HOCs on the sulfation of 3,3'-T2, a major substrate for TH sulfation. For the formation of 3,3'-T2S, the Michaelis constant (Km) was 1070 ± 120 nM and the Vmax was 153 ± 6.6 pmol min(-1) (mg of protein)(-1). All chemicals investigated inhibited sulfotransferase activity with the exception of BDE 47. The 2,4,6-trihalogenated phenols were the most potent inhibitors followed by the OH BDEs and then halogenated BPAs. The IC50 values for the OH BDEs were primarily in the low nanomolar range, which may be environmentally relevant. In silico molecular modeling techniques were also used to simulate the binding of OH BDE to SULT1A1. This study suggests that some HOCs, including antimicrobial chemicals and metabolites of flame retardants, may interfere with TH regulation through inhibition of sulfotransferase activity.
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Affiliation(s)
- Craig M Butt
- Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States
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Murk AJ, Rijntjes E, Blaauboer BJ, Clewell R, Crofton KM, Dingemans MML, Furlow JD, Kavlock R, Köhrle J, Opitz R, Traas T, Visser TJ, Xia M, Gutleb AC. Mechanism-based testing strategy using in vitro approaches for identification of thyroid hormone disrupting chemicals. Toxicol In Vitro 2013; 27:1320-46. [PMID: 23453986 DOI: 10.1016/j.tiv.2013.02.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Revised: 02/07/2013] [Accepted: 02/18/2013] [Indexed: 11/16/2022]
Abstract
The thyroid hormone (TH) system is involved in several important physiological processes, including regulation of energy metabolism, growth and differentiation, development and maintenance of brain function, thermo-regulation, osmo-regulation, and axis of regulation of other endocrine systems, sexual behaviour and fertility and cardiovascular function. Therefore, concern about TH disruption (THD) has resulted in strategies being developed to identify THD chemicals (THDCs). Information on potential of chemicals causing THD is typically derived from animal studies. For the majority of chemicals, however, this information is either limited or unavailable. It is also unlikely that animal experiments will be performed for all THD relevant chemicals in the near future for ethical, financial and practical reasons. In addition, typical animal experiments often do not provide information on the mechanism of action of THDC, making it harder to extrapolate results across species. Relevant effects may not be identified in animal studies when the effects are delayed, life stage specific, not assessed by the experimental paradigm (e.g., behaviour) or only occur when an organism has to adapt to environmental factors by modulating TH levels. Therefore, in vitro and in silico alternatives to identify THDC and quantify their potency are needed. THDC have many potential mechanisms of action, including altered hormone production, transport, metabolism, receptor activation and disruption of several feed-back mechanisms. In vitro assays are available for many of these endpoints, and the application of modern '-omics' technologies, applicable for in vivo studies can help to reveal relevant and possibly new endpoints for inclusion in a targeted THDC in vitro test battery. Within the framework of the ASAT initiative (Assuring Safety without Animal Testing), an international group consisting of experts in the areas of thyroid endocrinology, toxicology of endocrine disruption, neurotoxicology, high-throughput screening, computational biology, and regulatory affairs has reviewed the state of science for (1) known mechanisms for THD plus examples of THDC; (2) in vitro THD tests currently available or under development related to these mechanisms; and (3) in silico methods for estimating the blood levels of THDC. Based on this scientific review, the panel has recommended a battery of test methods to be able to classify chemicals as of less or high concern for further hazard and risk assessment for THD. In addition, research gaps and needs are identified to be able to optimize and validate the targeted THD in vitro test battery for a mechanism-based strategy for a decision to opt out or to proceed with further testing for THD.
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Affiliation(s)
- AlberTinka J Murk
- Wageningen University, Sub-department of Toxicology, Tuinlaan 5, 6703 HE Wageningen, The Netherlands.
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Koeppe ES, Ferguson KK, Colacino JA, Meeker JD. Relationship between urinary triclosan and paraben concentrations and serum thyroid measures in NHANES 2007-2008. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 445-446:299-305. [PMID: 23340023 PMCID: PMC3572338 DOI: 10.1016/j.scitotenv.2012.12.052] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/17/2012] [Accepted: 12/17/2012] [Indexed: 04/15/2023]
Abstract
Triclosan and parabens are broad spectrum antimicrobials used in a range of consumer products. In vitro and animal studies have suggested the potential for these compounds to disrupt thyroid function, though studies in humans have been limited. The objective of the study was to assess the relationship of urinary concentrations of triclosan and parabens with serum thyroid measures in a large, representative sample of the US population. We conducted an exploratory, cross-sectional analysis of data on urinary biomarkers of triclosan and paraben exposure and serum thyroid measures obtained from 1831 subjects (ages≥12 years) as part of the 2007-2008 National Health and Nutrition Examination Survey (NHANES). We found evidence of some inverse associations between parabens and circulating thyroid hormone levels in adults, with the strongest and most consistent associations among females. We also observed a positive association between triclosan and total triiodothyonine (T3) concentrations in adolescents. These results, in accordance with the in vitro and animal literature, suggest that paraben, and potentially triclosan, exposures may be associated with altered thyroid hormone levels in humans. Further research is needed for confirmation and to determine the potential clinical and public health significance of these findings.
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Affiliation(s)
- Erika S. Koeppe
- Department of Environmental Health Sciences, University of Michigan School of Public Health Ann Arbor, MI
| | - Kelly K. Ferguson
- Department of Environmental Health Sciences, University of Michigan School of Public Health Ann Arbor, MI
| | - Justin A. Colacino
- Department of Environmental Health Sciences, University of Michigan School of Public Health Ann Arbor, MI
| | - John D. Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health Ann Arbor, MI
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Hontela A, Habibi HR. Personal Care Products in the Aquatic Environment: A Case Study on the Effects of Triclosan in Fish. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-398254-4.00008-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
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Springer C, Dere E, Hall SJ, McDonnell EV, Roberts SC, Butt CM, Stapleton HM, Watkins DJ, McClean MD, Webster TF, Schlezinger JJ, Boekelheide K. Rodent thyroid, liver, and fetal testis toxicity of the monoester metabolite of bis-(2-ethylhexyl) tetrabromophthalate (tbph), a novel brominated flame retardant present in indoor dust. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1711-9. [PMID: 23014847 PMCID: PMC3548273 DOI: 10.1289/ehp.1204932] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 09/26/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND Bis-(2-ethylhexyl) tetrabromophthalate (TBPH) is widely used as a replacement for polybrominated diphenyl ethers (PBDEs) in commercial flame retardant mixtures such as Firemaster 550. It is also used in a commercial mixture called DP 45. Mono-(2-ethyhexyl) tetrabromophthalate (TBMEHP) is a potentially toxic metabolite. OBJECTIVES We used in vitro and rodent in vivo models to evaluate human exposure and the potential metabolism and toxicity of TBPH. METHODS Dust collected from homes, offices, and cars was measured for TBPH by gas chromatography followed by mass spectrometry. Pregnant rats were gavaged with TBMEHP (200 or 500 mg/kg) or corn oil on gestational days 18 and 19, and dams and fetuses were evaluated histologically for toxicity. We also assessed TBMEHP for deiodinase inhibition using rat liver microsomes and for peroxisome proliferator-activated receptor (PPAR) α and γ activation using murine FAO cells and NIH 3T3 L1 cells. RESULTS TBPH concentrations in dust from office buildings (median, 410 ng/g) were higher than in main living areas in homes (median, 150 ng/g). TBPH was metabolized by purified porcine esterases to TBMEHP. Two days of TBMEHP exposure in the rat produced maternal hypothyroidism with markedly decreased serum T3 (3,3´,5-triiodo-l-thyronine), maternal hepatotoxicity, and increased multinucleated germ cells (MNGs) in fetal testes without antiandrogenic effects. In vitro, TBMEHP inhibited deiodinase activity, induced adipocyte differentiation in NIH 3T3 L1 cells, and activated PPARα- and PPARγ-mediated gene transcription in NIH 3T3 L1 cells and FAO cells, respectively. CONCLUSIONS TBPH a) is present in dust from indoor environments (implying human exposure) and b) can be metabolized by porcine esterases to TBMEHP, which c) elicited maternal thyrotoxic and hepatotoxic effects and d) induced MNGs in the fetal testes in a rat model. In mouse NIH 3T3 L1 preadipocyte cells, TBMEHP inhibited rat hepatic microsome deiodinase activity and was an agonist for PPARs in murine FAO and NIH 3T3 L1 cells.
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Affiliation(s)
- Cecilia Springer
- Department of Pathology and Laboratory Medicine, Brown University, Providence, Rhode Island 02912, USA
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Hisada A, Shimodaira K, Okai T, Watanabe K, Takemori H, Takasuga T, Noda Y, Shirakawa M, Kato N, Yoshinaga J. Serum levels of hydroxylated PCBs, PCBs and thyroid hormone measures of Japanese pregnant women. Environ Health Prev Med 2012; 18:205-14. [PMID: 23054994 DOI: 10.1007/s12199-012-0306-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 09/04/2012] [Indexed: 01/07/2023] Open
Abstract
OBJECTIVES The purpose of this study was to investigate the associations between serum concentrations of hydroxylated PCBs (OH-PCBs) and PCBs and measures of thyroid hormone status of Japanese pregnant women. METHODS The concentrations of free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroxine binding globulin (TBG) as well as 16 OH-PCB isomers and 29 PCB isomers were analyzed in the serum of 129 women sampled in the first trimester of gestation. Dietary and lifestyle information of the subjects was obtained by self-administered questionnaire. Multiple regression analysis was performed using measures of thyroid hormones as the dependent variable and serum levels of OH-PCBs/PCBs, urinary iodine concentration, and other potential covariates (age, BMI, smoking, etc.) as independent variables. RESULTS Geometric mean (GM) concentration of the sum of 16 isomers of OH-PCBs was 120 pg/g wet wt. and that of 29 isomers of PCBs was 68 ng/g lipid wt., respectively, in the serum of the subjects. Iodine nutrition was considered adequate to high from urinary iodine level (GM, 370 μg/g creatinine). The mean concentration of TSH, fT4 and TBG was 1.34 ± 1.37 μIU/mL, 1.22 ± 0.16 ng/dL and 33.0 ± 6.4 μg/mL, respectively, with a small number of subjects who were outside the reference range. Multiple regression analysis revealed that serum concentrations of OH-PCBs/PCBs were not significantly associated with any of the measures of thyroid hormone status. CONCLUSIONS Exposure/body burden of OH-PCBs and PCBs at environmental levels does not have a measurable effect on thyroid hormones.
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Affiliation(s)
- Aya Hisada
- Department of Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan
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41
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Boas M, Feldt-Rasmussen U, Main KM. Thyroid effects of endocrine disrupting chemicals. Mol Cell Endocrinol 2012; 355:240-8. [PMID: 21939731 DOI: 10.1016/j.mce.2011.09.005] [Citation(s) in RCA: 421] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/29/2011] [Accepted: 09/02/2011] [Indexed: 11/17/2022]
Abstract
In recent years, many studies of thyroid-disrupting effects of environmental chemicals have been published. Of special concern is the exposure of pregnant women and infants, as thyroid disruption of the developing organism may have deleterious effects on neurological outcome. Chemicals may exert thyroid effects through a variety of mechanisms of action, and some animal experiments and in vitro studies have focused on elucidating the mode of action of specific chemical compounds. Long-term human studies on effects of environmental chemicals on thyroid related outcomes such as growth and development are still lacking. The human exposure scenario with life long exposure to a vast mixture of chemicals in low doses and the large physiological variation in thyroid hormone levels between individuals render human studies very difficult. However, there is now reasonably firm evidence that PCBs have thyroid-disrupting effects, and there is emerging evidence that also phthalates, bisphenol A, brominated flame retardants and perfluorinated chemicals may have thyroid disrupting properties.
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Affiliation(s)
- Malene Boas
- Department of Growth and Reproduction GR, Rigshospitalet, University of Copenhagen, Denmark.
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42
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Toms LML, Allmyr M, Mueller JF, Adolfsson-Erici M, McLachlan M, Murby J, Harden FA. Triclosan in individual human milk samples from Australia. CHEMOSPHERE 2011; 85:1682-6. [PMID: 22000243 DOI: 10.1016/j.chemosphere.2011.08.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Revised: 07/18/2011] [Accepted: 08/04/2011] [Indexed: 05/22/2023]
Abstract
Triclosan is a chlorinated phenol ether that has been in widespread use as a broad-spectrum antibacterial agent for four decades. When compared to the limited international data available on human body burden of triclosan, results from a pooled blood study suggested that triclosan concentrations in Australia were a factor two higher than observed in Sweden. This study determined triclosan levels in individual human milk samples (n=151) collected between 2002 and 2005 from primiparous Australian mothers. It provided the first report of population triclosan levels and individual variation in Australia and gave a measure of infant exposure via breast feeding. The distribution of triclosan concentration was positively skewed, with 7.2% of the samples below the LOQ, 66% with a concentration of less than or equal to 1.0 ng g(-1)fresh weight and the remaining samples above 1 ng g(-1) reaching a maximum concentration of 19 ng g(-1)fresh weight. The mean and median triclosan concentrations were 1.3±2.7 ng g(-1)f.w. and 0.26 ng g(-1)f.w., respectively. The results of this study showed high variability in triclosan concentrations between individuals and no correlations with maternal age (p=0.094), maternal weight (p=0.971) or infant age at the time of sample collection (p=0.621). A large number of samples contained low or non-quantifiable concentrations of triclosan and so, in Australia, ubiquitous background exposure due to environmental sources is low. This means that body burden can be influenced by an individual's use of triclosan containing product. Given that triclosan containing product use is continuing, it is important that monitoring in both humans and the environment is continued and that triclosan containing products are adequately labeled so that an individual can choose to avoid exposure.
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Affiliation(s)
- Leisa-Maree L Toms
- National Research Centre for Environmental Toxicology (Entox), The University of Queensland, Brisbane, Australia.
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Dann AB, Hontela A. Triclosan: environmental exposure, toxicity and mechanisms of action. J Appl Toxicol 2011; 31:285-311. [PMID: 21462230 DOI: 10.1002/jat.1660] [Citation(s) in RCA: 543] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol; TCS] is a broad spectrum antibacterial agent used in personal care, veterinary, industrial and household products. TCS is commonly detected in aquatic ecosystems, as it is only partially removed during the wastewater treatment process. Sorption, biodegradation and photolytic degradation mitigate the availability of TCS to aquatic biota; however the by-products such as methyltriclosan and other chlorinated phenols may be more resistant to degradation and have higher toxicity than the parent compound. The continuous exposure of aquatic organisms to TCS, coupled with its bioaccumulation potential, have led to detectable levels of the antimicrobial in a number of aquatic species. TCS has been also detected in breast milk, urine and plasma, with levels of TCS in the blood correlating with consumer use patterns of the antimicrobial. Mammalian systemic toxicity studies indicate that TCS is neither acutely toxic, mutagenic, carcinogenic, nor a developmental toxicant. Recently, however, concern has been raised over TCS's potential for endocrine disruption, as the antimicrobial has been shown to disrupt thyroid hormone homeostasis and possibly the reproductive axis. Moreover, there is strong evidence that aquatic species such as algae, invertebrates and certain types of fish are much more sensitive to TCS than mammals. TCS is highly toxic to algae and exerts reproductive and developmental effects in some fish. The potential for endocrine disruption and antibiotic cross-resistance highlights the importance of the judicious use of TCS, whereby the use of TCS should be limited to applications where it has been shown to be effective.
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Affiliation(s)
- Andrea B Dann
- Department of Biological Sciences, Alberta Water and Environmental Science Bldg, 4401 University Dr. W., University of Lethbridge, Lethbridge, Alberta, Canada
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Fort DJ, Mathis MB, Hanson W, Fort CE, Navarro LT, Peter R, Büche C, Unger S, Pawlowski S, Plautz JR. Triclosan and thyroid-mediated metamorphosis in anurans: differentiating growth effects from thyroid-driven metamorphosis in Xenopus laevis. Toxicol Sci 2011; 121:292-302. [PMID: 21436124 DOI: 10.1093/toxsci/kfr069] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In a previously reported study, we used a standard metamorphosis anuran model to assess potential effect of the antibacterial agent triclosan (TCS) on normal prometamorphic Xenopus laevis. Results indicated that environmentally relevant TCS concentrations did not alter the normal course of thyroid-mediated metamorphosis in this standard anuran model. However, to examine potential effects of TCS exposure during premetamorphosis and to distinguish between effects on metamorphosis and effects on growth, a longer term TCS exposure study was conducted. Standard Nieuwkoop and Faber (NF) stage 47 X. laevis larvae were exposed for 32 days (ca. NF stage 59-60) via flow-through to four different concentrations of TCS: < 0.2 (control), 0.8, 3.1, 12.5, or 50.0 μg TCS/l. Primary endpoints were survival, hind limb length, body length (whole; snout-to-vent), developmental stage, wet whole body weight, thyroid histology, plasma thyroid hormone (TH) concentrations, TH receptor beta (TRβ), and type II and III deiodinase (DI-2 and DI-3) expression. Endpoints measured to evaluate effects on thyroid-mediated metamorphosis including developmental stage, thyroid histology, TRβ expression, DI-2 and DI-3 expression, and thyroid gland 3,5,3',5'-tetraiodothyronine (T4) and plasma T4 and 3,5,3'-triiodothyronine (T3) levels were not affected by TCS exposure. However, increased larval growth based on whole body length (0.78, 12.5, and 50 μg TCS/l), snout-vent length (3.1 and 12.5 μg TCS/l), and whole body weight (0.8, 12.5, and 50.0 μg TCS/l) was observed following 32-day TCS exposure. These results indicated that TCS exposure during pre- and prometamorphosis increased larval growth but did not alter the normal course of metamorphosis in X. laevis. The increased growth associated with TCS exposure was not unexpected and is generally consistent with the presence of reduced bacterial stressors in culture.
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Affiliation(s)
- Douglas J Fort
- Fort Environmental Laboratories, Stillwater, Oklahoma 74074, USA.
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45
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Butt CM, Wang D, Stapleton HM. Halogenated phenolic contaminants inhibit the in vitro activity of the thyroid-regulating deiodinases in human liver. Toxicol Sci 2011; 124:339-47. [PMID: 21565810 DOI: 10.1093/toxsci/kfr117] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Halogenated contaminants, particularly brominated flame retardants, disrupt circulating levels of thyroid hormones (THs), potentially affecting growth and development. Disruption may be mediated by impacts on deiodinase (DI) activity, which regulate the levels of active hormones available to bind to nuclear receptors. The goal of this study was to develop a mass spectrometry-based method for measuring the activity of DIs in human liver microsomes and to examine the effect of halogenated phenolic contaminants on DI activity. Thyroxine (T4) and reverse triiodothyronine (rT3) deiodination kinetics were measured by incubating pooled human liver microsomes with T4 or rT3 and monitoring the production of T3, rT3, 3,3'-diiodothyronine, and 3-monoiodothyronine by liquid chromatography tandem mass spectrometry. Using this method, we examined the effects of several halogenated contaminants, including 2,2',4,4',5-pentabromodiphenyl ether (BDE 99), several hydroxylated polybrominated diphenyl ethers (OH-BDEs), tribromophenol, tetrabromobisphenol A, and triclosan, on DI activity. The Michaelis constants (K(M)) of rT3 and T4 deiodination were determined to be 3.2 ± 0.7 and 17.3 ± 2.3μM. The V(max) was 160 ± 5.8 and 2.8 ± 0.10 pmol/min.mg protein, respectively. All studied contaminants inhibited DI activity in a dose-response manner, with the exception of BDE 99 and two OH-BDEs. 5'-Hydroxy 2,2',4,4',5-pentabromodiphenyl ether was found to be the most potent inhibitor of DI activity, and phenolic structures containing iodine were generally more potent inhibitors of DI activity relative to brominated, chlorinated, and fluorinated analogues. This study suggests that some halogenated phenolics, including current use compounds such as plastic monomers, flame retardants, and their metabolites, may disrupt TH homeostasis through the inhibition of DI activity in vivo.
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Affiliation(s)
- Craig M Butt
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, USA
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Freitas J, Cano P, Craig-Veit C, Goodson ML, David Furlow J, Murk AJ. Detection of thyroid hormone receptor disruptors by a novel stable in vitro reporter gene assay. Toxicol In Vitro 2011; 25:257-66. [DOI: 10.1016/j.tiv.2010.08.013] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 07/29/2010] [Accepted: 08/16/2010] [Indexed: 10/19/2022]
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47
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Li X, Parkin S, Duffel MW, Robertson LW, Lehmler HJ. An efficient approach to sulfate metabolites of polychlorinated biphenyls. ENVIRONMENT INTERNATIONAL 2010; 36:843-8. [PMID: 19345419 PMCID: PMC2939219 DOI: 10.1016/j.envint.2009.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 02/04/2009] [Accepted: 02/06/2009] [Indexed: 05/02/2023]
Abstract
Polychlorinated biphenyls (PCBs), a major class of persistent organic pollutants, are metabolized to hydroxylated PCBs. Several hydroxylated PCBs are substrates of cytosolic phase II enzymes, such as phenol and hydroxysteroid (alcohol) sulfotransferases; however, the corresponding sulfation products have not been isolated and characterized. Here we describe a straightforward synthesis of a series of ten PCB sulfate monoesters from the corresponding hydroxylated PCBs. The hydroxylated PCBs were synthesized by coupling chlorinated benzene boronic acids with appropriate brominated (chloro-)anisoles, followed by demethylation with boron tribromide. The hydroxylated PCBs were sulfated with 2,2,2-trichloroethyl chlorosulfate using DMAP as base. Deprotection with zinc powder/ammonium formate yielded the ammonium salts of the desired PCB sulfate monoesters in good yields when the sulfated phenyl ring contained no or one chlorine substituent. However, no PCB sulfate monoesters were isolated when two chlorines were present ortho to the sulfated hydroxyl group. To aid with future quantitative structure activity relationship studies, the structures of two 2,2,2-trichloroethyl-protected PCB sulfates were verified by X-ray diffraction.
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Affiliation(s)
- Xueshu Li
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Sean Parkin
- Department of Chemistry, College of Arts and Sciences, University of Kentucky, Lexington, KY, 40506, USA
| | - Michael W. Duffel
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, Iowa City, IA, 52242, USA
| | - Larry W. Robertson
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, IA, 52242, USA
- Corresponding Author: Hans-Joachim Lehmler, Department of Occupational and Environmental Health, College of Public Health, University of Iowa 100 Oakdale Campus #221 IREH Iowa City, IA 52242-5000, Phone +1 (319) 335-4211, Fax: +1 (319) 335-4290, e-mail:
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Sonne C. Health effects from long-range transported contaminants in Arctic top predators: An integrated review based on studies of polar bears and relevant model species. ENVIRONMENT INTERNATIONAL 2010; 36:461-491. [PMID: 20398940 DOI: 10.1016/j.envint.2010.03.002] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 03/06/2010] [Accepted: 03/10/2010] [Indexed: 05/29/2023]
Abstract
The aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (OCs), polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs) and mercury (Hg) on polar bear (Ursus maritimus) health. Multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do not represent true cause-and-effects. Therefore, information from controlled studies of farmed Norwegian Arctic foxes (Vulpes lagopus) and housed East and West Greenland sledge dogs (Canis familiaris) were included as supportive weight of evidence in the clarification of contaminant exposure and health effects in polar bears. The review showed that hormone and vitamin concentrations, liver, kidney and thyroid gland morphology as well as reproductive and immune systems of polar bears are likely to be influenced by contaminant exposure. Furthermore, exclusively based on polar bear contaminant studies, bone density reduction and neurochemical disruption and DNA hypomethylation of the brain stem seemed to occur. The range of tissue concentration, at which these alterations were observed in polar bears, were ca. 1-70,000 ng/g lw for OCs (blood plasma concentrations of some PCB metabolites even higher), ca. 1-1000 ng/g lw for PBDEs and for PFCs and Hg 114-3052 ng/g ww and 0.1-50 microg/g ww, respectively. Similar concentrations were found in farmed foxes and housed sledge dogs while the lack of dose response designs did not allow an estimation of threshold levels for oral exposure and accumulated tissue concentrations. Nor was it possible to pinpoint a specific group of contaminants being more important than others nor analyze their interactions. For East Greenland polar bears the corresponding daily SigmaOC and SigmaPBDE oral exposure was estimated to be 35 and 0.34 microg/kg body weight, respectively. Furthermore, PFC concentrations, at which population effect levels could occur, are likely to be reached around year 2012 for the East Greenland polar bear subpopulation if current increasing temporal trends continue. Such proposed reproductive population effects were supported by physiological based pharmacokinetic (PBPK) modelling of critical body residues (CBR) with risk quotients >or=1 for SigmaPCB, dieldrin, SigmaPFC and SigmaOHC (organohalogen contaminant). The estimated daily TEQ for East Greenland polar bears and East Greenland sledge dogs were 32-281-folds above WHO SigmaTEQ guidelines for humans. Compared to human tolerable daily intake (TDI), these were exceeded for PCBs, dieldrin, chlordanes and SigmaHCH in East Greenland polar bears. Comparisons like these should be done with caution, but together with the CBR modelling and T-score estimations, these were the only available tools for polar bear risk evaluation. In conclusion, polar bears seem to be susceptible to contaminant induced stress that may have an overall sub-clinical impact on their health and population status via impacts on their immune and reproductive systems.
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Affiliation(s)
- Christian Sonne
- Section for Contaminants, Effects and Marine Mammals, Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, DK-4000 Roskilde, Denmark.
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Dirtu AC, Jaspers VLB, Cernat R, Neels H, Covaci A. Distribution of PCBs, their hydroxylated metabolites, and other phenolic contaminants in human serum from two European countries. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:2876-2883. [PMID: 20384379 DOI: 10.1021/es902149b] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Human exposure to mixtures of polychlorinated biphenyls (PCBs) may result in the formation of different profiles of hydroxylated PCBs (HO-PCBs), as a consequence of different exposures or dissimilar metabolism of parent compounds. Therefore, we investigated the levels and profiles of PCBs and HO-PCBs in human serum samples collected from two European countries with different degrees of pollution. There was no significant difference between the levels of sum PCBs measured in each set of samples, with a median concentration of 3100 pg/mL for Romanian samples (n = 53) and 3380 pg/mL for Belgian samples (n = 22). However, the median concentrations recorded for sum HO-PCBs were almost double in Belgian (310 pg/mL) compared to Romanian (175 pg/mL) samples. The detection frequency recorded for HO-PCBs in Belgian samples was also significantly higher compared to Romanian samples. The main contributors to the sum HO-PCBs in the Belgian samples were 4HO-CB107 > 4HO-CB146 > 4HO-CB187 (76% from the sum HO-PCBs) and 4HO-CB187 > 4HO-CB146 > 3'HO-CB138 (66% from the sum of HO-PCBs) in the Romanian samples. The HO-PCB profile showed that the higher chlorinated HO-PCBs had a higher contribution in the Romanian samples compared to the Belgian ones. This suggests that differences in the PCB profiles between populations can lead to the formation of different HO-PCB metabolite profiles presenting thus different risks for populations. No clear preferential mechanism of HO-PCB metabolite formation (HO-direct insertion vs. 1,2-shift of a chlorine atom) could be highlighted for investigated samples. The main chlorinated phenolic compound found in the Belgian samples was pentachlorophenol (PCP) which accounted for up to 85% of the total quantified phenolics, whereas in the Romanian samples, PCP accounted for only 35%.
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Affiliation(s)
- Alin C Dirtu
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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Rahman FB, Yamauchi K. Characterization of iodothyronine sulfotransferase activity in the cytosol of Rana catesbeiana tadpole tissues. Gen Comp Endocrinol 2010; 166:396-403. [PMID: 20036241 DOI: 10.1016/j.ygcen.2009.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 12/15/2009] [Accepted: 12/16/2009] [Indexed: 11/23/2022]
Abstract
We have investigated the sulfation of thyroid hormones (THs) in the cytosol from Rana catesbeiana tadpole tissues. Sulfation of 3,3',5-triiodothyronine (T(3)) by the liver cytosol, which was dependent on protein amount, incubation time, and temperature, suggested the presence of TH sulfotransferases (SULTs) in the liver. The apparent Michaelis-Menten constant (K(m)) of the liver cytosol was 0.22 microM for T(3), and the apparent maximum velocity (V(max)) of the liver cytosol was 7.65 pmol/min/mg protein for T(3). Iodothyronine sulfating activity in the liver cytosol was increased in tadpoles at premetamorphic (stages IX-X) and metamorphic climax (stage XX) stages, and in adult frogs. The substrate preference of iodothyronine sulfation for the liver cytosol from tadpoles (stage X) was: 3,3',5'-triiodothyronine>T(3)>3,3',5,5'-tetraiodothyroacetic acid>3,3',5-triiodothyroacetic acid, T(4), 3-iodothyronine>3,5-diiodothyronine. Several halogenated phenols were potent inhibitors (IC(50)=0.15-0.21 microM). The substrate preference for T(3) was gradually lost by the onset of metamorphic climax stages. These enzymatic characteristics of iodothyronine sulfation in the liver cytosol from tadpoles resembled those of mammalian phenol SULTs, except that the tadpole cytosol had a higher affinity (one or two orders of magnitude) for T(3) than mammalian SULTs. These results suggested that an enzyme homologous to mammalian phenol SULT (SULT1) may be involved in TH metabolism in tadpoles.
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Affiliation(s)
- Farhana Babli Rahman
- Graduate School of Science and Engineering, Shizuoka University, Shizuoka 422-8529, Japan
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