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Liu R, Zacharewski TR, Conolly RB, Zhang Q. A Physiologically Based Pharmacokinetic (PBPK) Modeling Framework for Mixtures of Dioxin-like Compounds. TOXICS 2022; 10:toxics10110700. [PMID: 36422908 PMCID: PMC9698634 DOI: 10.3390/toxics10110700] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/03/2022] [Accepted: 11/15/2022] [Indexed: 06/08/2023]
Abstract
Humans are exposed to persistent organic pollutants, such as dioxin-like compounds (DLCs), as mixtures. Understanding and predicting the toxicokinetics and thus internal burden of major constituents of a DLC mixture is important for assessing their contributions to health risks. PBPK models, including dioxin models, traditionally focus on one or a small number of compounds; developing new or extending existing models for mixtures often requires tedious, error-prone coding work. This lack of efficiency to scale up for multi-compound exposures is a major technical barrier toward large-scale mixture PBPK simulations. Congeners in the DLC family, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), share similar albeit quantitatively different toxicokinetic and toxicodynamic properties. Taking advantage of these similarities, here we reported the development of a human PBPK modeling framework for DLC mixtures that can flexibly accommodate an arbitrary number of congeners. Adapted from existing TCDD models, our mixture model contains the blood and three diffusion-limited compartments-liver, fat, and rest of the body. Depending on the number of congeners in a mixture, varying-length vectors of ordinary differential equations (ODEs) are automatically generated to track the tissue concentrations of the congeners. Shared ODEs are used to account for common variables, including the aryl hydrocarbon receptor (AHR) and CYP1A2, to which the congeners compete for binding. Binary and multi-congener mixture simulations showed that the AHR-mediated cross-induction of CYP1A2 accelerates the sequestration and metabolism of DLC congeners, resulting in consistently lower tissue burdens than in single exposure, except for the liver. Using dietary intake data to simulate lifetime exposures to DLC mixtures, the model demonstrated that the relative contributions of individual congeners to blood or tissue toxic equivalency (TEQ) values are markedly different than those to intake TEQ. In summary, we developed a mixture PBPK modeling framework for DLCs that may be utilized upon further improvement as a quantitative tool to estimate tissue dosimetry and health risks of DLC mixtures.
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Affiliation(s)
- Rongrui Liu
- Lower Merion High School, Ardmore, PA 19003, USA
| | - Tim R. Zacharewski
- Department of Biochemistry and Molecular Biology, Institute for Integrative Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
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2
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Vieira Silva A, Chu I, Feeley M, Bergman Å, Håkansson H, Öberg M. Dose-dependent toxicological effects in rats following a 90-day dietary exposure to PCB-156 include retinoid disruption. Reprod Toxicol 2022; 107:123-139. [PMID: 34560258 DOI: 10.1016/j.reprotox.2021.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 09/01/2021] [Accepted: 09/16/2021] [Indexed: 12/21/2022]
Abstract
The toxicity of PCB-156 (2,3,3',4,4',5-hexachlorobiphenyl) was investigated in rats following subchronic dietary exposure. Groups of 10 male and female Sprague-Dawley rats were administered PCB-156 in the diet at 0, 0.01, 0.1, 1 or 10 ppm for 90 days. Dose-dependent increases were detected for the liver, lung and kidney weights, as well as for the liver EROD, PROD and UDPGT enzyme activities and liver uroporphyrin concentration. Dose-dependent decreases were observed in final body weight, body weight gain, and thymus weight. Apolar retinoid concentrations were decreased in the liver and lungs and increased in the kidneys. Histopathological examination of the liver, thyroid, and thymus showed mild to moderate dose-related changes. A LOAEL of 0.01 ppm was established, based on reduced apolar liver retinoid concentration. Benchmark dose-modelling corroborated the sensitivity of liver retinoid endpoints. The lower confidence limits (BMDL) for a 5% decrease in apolar liver retinoid concentrations were 0.0009 and 0.0007 ppm, respectively, in males and females, corresponding to a daily dose of 0.06 μg PCB-156 per kg body weight. Organizing dose-response data for the individual hepatic endpoints along the PCB-156 dosing scale revealed a sequence of events compatible with a causal link between depletion of apolar retinoids and the other liver biochemistry and pathology findings. Taken together, data suggest that the retinoid endpoints should be further evaluated for a causal relationship to PCB-induced liver toxicity and that retinoid system endpoints are identified and characterized to support health risk assessment in the emerging research fields of endocrine disruption and mixture toxicology.
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Affiliation(s)
- A Vieira Silva
- Unit of Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
| | - I Chu
- Health Canada Tunney's Pasture, Ottawa, Ontario, Canada
| | - M Feeley
- Health Canada Tunney's Pasture, Ottawa, Ontario, Canada
| | - Å Bergman
- Department of Environmental Science (ACES), Stockholm University, Stockholm, Sweden; MTM, Department of Science and Technology, Örebro University, Örebro, Sweden
| | - H Håkansson
- Unit of Cardiovascular and Nutrition Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - M Öberg
- Unit of Integrative Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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3
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Wang C, Cui R, Niu C, Zhong X, Zhu Q, Ji D, Li X, Zhang H, Liu C, Zhou L, Li Y, Xu G, Wei Y. Low-dose PCB126 exposure disrupts cardiac metabolism and causes hypertrophy and fibrosis in mice. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 290:118079. [PMID: 34488161 DOI: 10.1016/j.envpol.2021.118079] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
The residue of polychlorinated biphenyls (PCBs) exists throughout the environment and humans are subject to long-term exposure. As such, the potential environmental and health risk caused by low-dose exposure to PCBs has attracted much attention. 3, 3', 4, 4', 5-pentachlorobiphenyl (PCB126), the highest toxicity compound among dioxin-like-PCBs, has been widely used and mass-produced. Cardiotoxicity is PCB126's crucial adverse effect. Maintaining proper metabolism underlies heart health, whereas the impact of PCB126 exposure on cardiac metabolic patterns has yet to be elucidated. In this study, we administered 0.5 and 50 μg/kg bw of PCB126 to adult male mice weekly by gavage for eight weeks. Pathological results showed that low-dose PCB126 exposure induced heart injury. Metabolomic analysis of the heart tissue exposed to low-dose PCB126 identified 59 differential metabolites that were involved in lipid metabolism, amino acid metabolism, and the tricarboxylic acid (TCA) cycle. Typical metabolomic characteristic of cardiac hypertrophy was reflected by accumulation of fatty acids (e.g. palmitic, palmitoleic, and linoleic acid), and disturbance of carbohydrates including D-glucose and intermediates in TCA cycle (fumaric, succinic, and citric acid). Low-dose PCB126 exposure increased glycine and threonine, the amino acids necessary for the productions of collagen and elastin. Besides, PCB126-exposed mice exhibited upregulation of collagen synthesis enzymes and extracellular matrix proteins, indicative of cardiac fibrosis. Moreover, the expression of genes related to TGFβ/PPARγ/MMP-2 signaling pathway was perturbed in the PCB126-treated hearts. Together, our results reveal that low-dose PCB126 exposure disrupts cardiac metabolism correlated with hypertrophy and fibrosis. This study sheds light on the underlying mechanism of PCBs' cardiotoxicity and identifies potential sensitive biomarkers for environmental monitoring.
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Affiliation(s)
- Can Wang
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ruina Cui
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Congying Niu
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Xiali Zhong
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Qicheng Zhu
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Di Ji
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Xianjie Li
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China
| | - Hongxia Zhang
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chunqiao Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, China
| | - Lina Zhou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Yanli Li
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Guowang Xu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
| | - Yanhong Wei
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Toxicology, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China.
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4
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Liberatori G, Cotugno P, Sturba L, Vannuccini ML, Capasso G, Velardo R, Besselink H, Massari F, Tursi A, Corbelli V, Behnisch PA, Corsi I. Occurrence and spatial distribution of dioxin and dioxin-like compounds in topsoil of Taranto (Apulia, Italy) by GC-MS analysis and DR-CALUX® bioassay. CHEMOSPHERE 2021; 279:130576. [PMID: 33894519 DOI: 10.1016/j.chemosphere.2021.130576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/02/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
The aim of the present study was to assess the occurrence and spatial distribution of PCDD/Fs and dioxin-like compounds in topsoils of Taranto (Apulia Region), one of the most heavily industrialized and contaminated area of Southern Italy. A combined approach of chemical analysis by GC-MS/MS and AhR reporter gene bioassay was applied in a subset of topsoil samples (n = 20) collected in 2017-18 from ten sites embracing three levels of risk (from high to low) in the framework of a large survey inside Taranto municipality. TCDD-BEQs and GC-MS/MS TEQWHO and TEQTHEORETICAL revealed a decreasing trend with the distance from main industrial settings and landfill areas. A strong correlation between TCDD-BEQs and TEQWHO values (R2 = 0.85) and TEQTHEORETICAL (R2 = 0.88) was also found. In 3 out of 10 topsoil investigated, BEQs and TEQWHO/THEORETICAL resulted above Italian National Regulatory Limits for ∑PCDD/Fs in green, private and recreational used soils (10 ng TEQ/kg d.w. D.Lgs 152/2006) and for ∑PCDD/F/dl-PCBs in agricultural and farming soil (6 ng TEQ/kg d.w. D.M. 46/2019). GC-MS/MS pattern revealed the highest prevalence of dl-PCBs in 6 out of 10 sites, followed by PCDFs and PCDDs. Those sites are all located in proximity of main industrial steel and iron ore sinter plant, steel plant's landfills and illegal dumping sites. An update on occurrence and spatial distribution of PCDD/Fs and dl-PCBs contamination of Taranto urban soils was obtained and the DR-CALUX® bioassay was further recommended as a suitable screening tool for environmental and human risk assessment.
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Affiliation(s)
- Giulia Liberatori
- Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy.
| | - Pietro Cotugno
- Department of Biology, University of Bari Aldo Moro, Bari, Italy
| | - Lucrezia Sturba
- Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy
| | - Maria Luisa Vannuccini
- Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy
| | - Gennaro Capasso
- Special Commissioner for Urgent Intervention for Remediation, Environmental Enhancement and Upgrading of Taranto, Taranto, Italy
| | - Raffaele Velardo
- Special Commissioner for Urgent Intervention for Remediation, Environmental Enhancement and Upgrading of Taranto, Taranto, Italy
| | | | - Federica Massari
- Department of Biology, University of Bari Aldo Moro, Bari, Italy
| | - Angelo Tursi
- Department of Biology, University of Bari Aldo Moro, Bari, Italy
| | - Vera Corbelli
- Special Commissioner for Urgent Intervention for Remediation, Environmental Enhancement and Upgrading of Taranto, Taranto, Italy
| | | | - Ilaria Corsi
- Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy
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Liu X, Zhang L, Li J, Wang J, Meng G, Chi M, Zhao Y, Wu Y. Relative Effect Potency Estimates for Dioxin-Like Compounds in Pregnant Women with Gestational Diabetes Mellitus and Blood Glucose Outcomes Based on a Nested Case-control Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7792-7802. [PMID: 31149810 DOI: 10.1021/acs.est.9b00988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
To improve the applicability of the toxic equivalents principle for human health risk assessment, systemic relative effect potencies (REPs) for dioxin-like compounds (DLCs) deriving from human in vivo data are required. A prospective nested case-control study was performed to determine REPs from the human serum concentration of DLCs using gestational diabetes mellitus (GDM) and fasting blood glucose (FBG) as the end points of concern. Serum concentration of 29 DLCs from 77 cases and 154 controls were measured. Logistic and linear regression were used to estimate the effects of individual congeners on GDM and FBG, respectively. The REPs based on GDM and FBG were calculated from the ratios of regression coefficients, βi (DLCs)/βTCDD. Two sets of consistent human serum-based REPs, that is, GDM-REP and FBG-REP, were established and largely agree with REPs from other human studies. These human-serum REPs show much smaller variation compared to the 4 to 5 orders of magnitude span in REPs database for the present WHO-TEF determination. Moreover, the established REPs fitted well with WHO-TEFs, especially for polychlorinated dibenzo- p-dioxins, furans. These REPs reflecting real human exposure scenarios exhibited validity and could be used to improve health risk assessment of human body burden of DLCs.
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Affiliation(s)
- Xin Liu
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
| | - Lei Zhang
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
| | - Jingguang Li
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
| | - Jun Wang
- Shenzhen Center for Chronic Disease Control , Shenzhen 518020 , China
| | - Guimin Meng
- Beijing Fengtai Hospital obstetrics and gynecology , Beijing 100071 , China
| | - Min Chi
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
- Taiyuan Center for Disease Control and Prevention , Taiyuan 030000 , China
| | - Yunfeng Zhao
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
| | - Yongning Wu
- NHC Key Laboratory of Food Safety Risk Assessment , China National Center for Food Safety Risk Assessment , Beijing 100021 , China
- State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang 330047 , China
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6
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Wahlang B, Barney J, Thompson B, Wang C, Hamad OM, Hoffman JB, Petriello MC, Morris AJ, Hennig B. Editor's Highlight: PCB126 Exposure Increases Risk for Peripheral Vascular Diseases in a Liver Injury Mouse Model. Toxicol Sci 2018; 160:256-267. [PMID: 28973532 DOI: 10.1093/toxsci/kfx180] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The liver is vital for xenobiotic and endobiotic metabolism. Previously, we demonstrated that a compromised liver worsened toxicity associated with exposure to polychlorinated biphenyls (PCBs), through disruption of energy homeostasis. However, the role of a compromised liver in defining dioxin-like PCB126 toxicity on the peripheral vasculature and associated inflammatory diseases is yet to be studied. This study investigated the effects of PCB126 on vascular inflammation linked to hepatic dysfunction utilizing a liver injury mouse model. Male C57Bl/6 mice were fed either an amino acid control diet (CD) or a methionine-choline deficient (MCD) diet in this 14-week study. Mice were exposed to PCB126 (0.5 mg/kg) and analyzed for inflammatory, calorimetric and metabolic parameters. MCD diet-fed mice demonstrated steatosis, indicative of a compromised liver. Mice fed the MCD-diet and subsequently exposed to PCB126 manifested lower body fat mass, increased liver to body weight ratio and alterations in hepatic gene expression related to lipid and carbohydrate metabolism, implicating metabolic disturbances. PCB126-induced steatosis irrespective of the diet type, but only the MCD + PCB126 group exhibited steatohepatitis and fibrosis. Furthermore, PCB126 exposure in MCD-fed mice led to increased plasma inflammatory markers such as Icam-1, plasminogen activator inhibitor-1 and proatherogenic trimethylamine-N-oxide, suggesting inflammation of the peripheral vasculature that is characteristic of atherosclerosis. Taken together, our data provide new evidence of a link between a compromised liver, PCB-mediated hepatic inflammation and vascular inflammatory markers, suggesting that environmental pollutants can promote crosstalk between different organ systems, leading to inflammatory disease pathologies.
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Affiliation(s)
- Banrida Wahlang
- University of Kentucky Superfund Research Center.,Department of Animal and Food Sciences, College of Agriculture, Food and Environment
| | - Jazmyne Barney
- University of Kentucky Superfund Research Center.,Department of Toxicology and Cancer Biology, College of Medicine
| | - Brendan Thompson
- University of Kentucky Superfund Research Center.,Department of Toxicology and Cancer Biology, College of Medicine
| | - Chunyan Wang
- University of Kentucky Superfund Research Center.,Department of Animal and Food Sciences, College of Agriculture, Food and Environment
| | - Omer M Hamad
- University of Kentucky Superfund Research Center
| | - Jessie B Hoffman
- University of Kentucky Superfund Research Center.,Graduate Center for Nutritional Sciences, College of Medicine
| | - Michael C Petriello
- University of Kentucky Superfund Research Center.,Division of Cardiovascular Medicine, College of Medicine, University of Kentucky, Lexington, Kentucky 40536.,Lexington Veterans Affairs Medical Center, Lexington, Kentucky
| | - Andrew J Morris
- University of Kentucky Superfund Research Center.,Division of Cardiovascular Medicine, College of Medicine, University of Kentucky, Lexington, Kentucky 40536.,Lexington Veterans Affairs Medical Center, Lexington, Kentucky
| | - Bernhard Hennig
- University of Kentucky Superfund Research Center.,Department of Animal and Food Sciences, College of Agriculture, Food and Environment.,Department of Toxicology and Cancer Biology, College of Medicine.,Graduate Center for Nutritional Sciences, College of Medicine
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7
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Strapáčová S, Brenerová P, Krčmář P, Andersson P, van Ede KI, van Duursen MB, van den Berg M, Vondráček J, Machala M. Relative effective potencies of dioxin-like compounds in rodent and human lung cell models. Toxicology 2018; 404-405:33-41. [DOI: 10.1016/j.tox.2018.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/11/2018] [Accepted: 05/02/2018] [Indexed: 12/23/2022]
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8
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van Ede KI, van Duursen MBM, van den Berg M. Evaluation of relative effect potencies (REPs) for dioxin-like compounds to derive systemic or human-specific TEFs to improve human risk assessment. Arch Toxicol 2016; 90:1293-305. [PMID: 27161441 PMCID: PMC4873528 DOI: 10.1007/s00204-016-1724-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 04/21/2016] [Indexed: 01/20/2023]
Abstract
Toxic equivalency factors (TEFs) are generally applied for estimating human risk of dioxins and dioxin-like compounds using systemic (e.g., blood) levels, even though these TEFs are established based on intake doses in rodent studies. This review shows that systemic relative effect potencies (REPs) can deviate substantially from intake REPs, but are similar to in vitro-derived REPs. Interestingly, the in vitro REPs for 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) and 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF) are up to one order of magnitude higher than their in vivo REPs and WHO-TEFs, based on oral intake. In addition, clear species-differences in in vitro REPs were apparent for some congeners. Especially the human-derived REP for polychlorinated biphenyl 126 is one to two orders of magnitude lower than rodent REPs and its current WHO-TEF. Next, suggested adapted systemic or human-specific TEFs for these congeners were applied to calculate changes in systemic TEQ concentrations in studies from the USA, Germany and Japan and compared with either the JECFA TDI or USEPA RfD of TCDD. Overall, the effect of such TEF changes for these three congeners on total TEQ roughly balances each other out in the general population. However, results may be different for situations in which a specific group of congeners dominates. For those congeners that show a distinct deviation between either intake and systemic REPs or between rodent- and human-based in vitro REPs, we propose that especially REPs derived from human-based in vitro models are weighted more heavily in establishing systemic or human-specific TEF values to improve human health risk assessment.
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Affiliation(s)
- Karin I van Ede
- Division of Toxicology and Veterinary Pharmacology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands.
| | - Majorie B M van Duursen
- Division of Toxicology and Veterinary Pharmacology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
| | - Martin van den Berg
- Division of Toxicology and Veterinary Pharmacology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, P.O. Box 80.177, NL-3508 TD, Utrecht, The Netherlands
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9
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Larsson M, van den Berg M, Brenerová P, van Duursen MBM, van Ede KI, Lohr C, Luecke-Johansson S, Machala M, Neser S, Pěnčíková K, Poellinger L, Schrenk D, Strapáčová S, Vondráček J, Andersson PL. Consensus toxicity factors for polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls combining in silico models and extensive in vitro screening of AhR-mediated effects in human and rodent cells. Chem Res Toxicol 2015; 28:641-50. [PMID: 25654323 DOI: 10.1021/tx500434j] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Consensus toxicity factors (CTFs) were developed as a novel approach to establish toxicity factors for risk assessment of dioxin-like compounds (DLCs). Eighteen polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and biphenyls (PCBs) with assigned World Health Organization toxic equivalency factors (WHO-TEFs) and two additional PCBs were screened in 17 human and rodent bioassays to assess their induction of aryl hydrocarbon receptor-related responses. For each bioassay and compound, relative effect potency values (REPs) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin were calculated and analyzed. The responses in the human and rodent cell bioassays generally differed. Most notably, the human cell models responded only weakly to PCBs, with 3,3',4,4',5-pentachlorobiphenyl (PCB126) being the only PCB that frequently evoked sufficiently strong responses in human cells to permit us to calculate REP values. Calculated REPs for PCB126 were more than 30 times lower than the WHO-TEF value for PCB126. CTFs were calculated using score and loading vectors from a principal component analysis to establish the ranking of the compounds and, by rescaling, also to provide numerical differences between the different congeners corresponding to the TEF scheme. The CTFs were based on rat and human bioassay data and indicated a significant deviation for PCBs but also for certain PCDD/Fs from the WHO-TEF values. The human CTFs for 2,3,4,7,8-pentachlorodibenzofuran, 1,2,3,4,7,8-hexachlorodibenzofuran, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, and 1,2,3,4,7,8,9-heptachlorodibenzofuran were up to 10 times greater than their WHO-TEF values. Quantitative structure-activity relationship models were used to predict CTFs for untested WHO-TEF compounds, suggesting that the WHO-TEF value for 1,2,3,7,8-pentachlorodibenzofuran could be underestimated by an order of magnitude for both human and rodent models. Our results indicate that the CTF approach provides a powerful tool for condensing data from batteries of screening tests using compounds with similar mechanisms of action, which can be used to improve risk assessment of DLCs.
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Affiliation(s)
- Malin Larsson
- †Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Martin van den Berg
- ‡Endocrine Toxicology Group, Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Petra Brenerová
- #Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Majorie B M van Duursen
- ‡Endocrine Toxicology Group, Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Karin I van Ede
- ‡Endocrine Toxicology Group, Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Christiane Lohr
- ⊥Department of Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Sandra Luecke-Johansson
- §Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Miroslav Machala
- #Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Sylke Neser
- ⊥Department of Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Kateřina Pěnčíková
- #Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Lorenz Poellinger
- §Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Dieter Schrenk
- ⊥Department of Food Chemistry and Environmental Toxicology, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Simona Strapáčová
- #Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Jan Vondráček
- #Department of Chemistry and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic.,∥Department of Cytokinetics, Institute of Biophysics AS CR, 612 65 Brno, Czech Republic
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Ghorbanzadeh M, van Ede KI, Larsson M, van Duursen MBM, Poellinger L, Lücke-Johansson S, Machala M, Pěnčíková K, Vondráček J, van den Berg M, Denison MS, Ringsted T, Andersson PL. In Vitro and in Silico Derived Relative Effect Potencies of Ah-Receptor-Mediated Effects by PCDD/Fs and PCBs in Rat, Mouse, and Guinea Pig CALUX Cell Lines. Chem Res Toxicol 2014; 27:1120-32. [DOI: 10.1021/tx5001255] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Karin I. van Ede
- Endocrine Toxicology Group, Institute for Risk Assessment
Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Malin Larsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Majorie B. M. van Duursen
- Endocrine Toxicology Group, Institute for Risk Assessment
Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Lorenz Poellinger
- Department
of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Sandra Lücke-Johansson
- Department
of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Miroslav Machala
- Department of Chemistry
and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Kateřina Pěnčíková
- Department of Chemistry
and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Jan Vondráček
- Department of Chemistry
and Toxicology, Veterinary Research Institute, 621 32 Brno, Czech Republic
| | - Martin van den Berg
- Endocrine Toxicology Group, Institute for Risk Assessment
Sciences, Utrecht University, P.O. Box 80177, NL-3508 TD Utrecht, The Netherlands
| | - Michael S. Denison
- Department of Environmental Toxicology, University of California, Davis, California 95616, United States
| | - Tine Ringsted
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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11
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van Ede KI, Gaisch KPJ, van den Berg M, van Duursen MBM. Differential relative effect potencies of some dioxin-like compounds in human peripheral blood lymphocytes and murine splenic cells. Toxicol Lett 2014; 226:43-52. [PMID: 24472611 DOI: 10.1016/j.toxlet.2014.01.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/16/2014] [Accepted: 01/17/2014] [Indexed: 11/29/2022]
Abstract
Human risk assessment for dioxin-like compounds is typically based on the concentration measured in blood serum multiplied by their assigned toxic equivalency factor (TEF). Consequently, the actual value of the TEF is very important for accurate human risk assessment. In this study we investigated the effect potencies of three polychlorinated dibenzo-p-dioxins (PCDDs), six polychlorinated dibenzofurans (PCDFs) and 10 polychlorinated biphenyls (PCBs) relative to the reference congener 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) in in vitro exposed primary human peripheral blood lymphocytes (PBLs) and mouse splenic cells. REPs were determined based on cytochrome P450 (CYP) 1A1, 1B1 and aryl hydrocarbon receptor repressor (AhRR) gene expression as well as CYP1A1 activity in human PBLs and Cyp1a1 gene expression in murine splenic cells. Estimated median human REPs for 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1234678-HpCDD), 2,3,4,7,8,-pentachlorodibenzofuran (23478-PeCDF), 1,2,3,4,7,8-hexachlorodibenzofuran (123478-HxCDF) and 1,2,3,4,7,8,9-heptachlorodibenzofuran (1234789-HpCDF) were with 0.1, 1.1, 1 and 0.09, respectively, significantly higher compared to those estimated for mouse with REPs of 0.05, 0.45, 0.09 and 0.04, respectively. Opposite to these results, the estimated median human REP of 3,3',4,4',5-pentachlorobiphenyl (PCB 126), was with 0.001 30-fold lower compared to the mouse REP of 0.03. Furthermore, human REPs for 1234678-HpCDD, 23478-PeCDF, 123478-HxCDF, 1234789-HpCDF and PCB 126 were all outside the ± half log uncertainty range that is taken into account in the WHO-assigned TEFs. Together, these data show congener- and species-specific differences in REPs for some, but not all dioxin-like congeners tested. This suggests that, more emphasis should be placed on human-tissue derived REPs in the establishment of a TEF for human risk assessment.
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Affiliation(s)
- Karin I van Ede
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM Utrecht, The Netherlands.
| | - Konrad P J Gaisch
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM Utrecht, The Netherlands.
| | - Martin van den Berg
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM Utrecht, The Netherlands.
| | - Majorie B M van Duursen
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM Utrecht, The Netherlands.
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12
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van Ede KI, Andersson PL, Gaisch KPJ, van den Berg M, van Duursen MBM. Comparison of intake and systemic relative effect potencies of dioxin-like compounds in female rats after a single oral dose. Arch Toxicol 2013; 88:637-46. [PMID: 24363026 DOI: 10.1007/s00204-013-1186-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 12/12/2013] [Indexed: 11/26/2022]
Abstract
Risk assessment for mixtures of dioxin-like compounds uses the toxic equivalency factor (TEF) approach. Although current WHO-TEFs are mostly based on oral administration, they are commonly used to determine toxicity equivalencies (TEQs) in human blood or tissues. However, the use of "intake" TEFs to calculate systemic TEQs in for example human blood, has never been validated. In this study, intake and systemic relative effect potencies (REPs) for 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), 3,3',4,4',5-pentachlorobiphenyl (PCB-126), 2,3',4,4',5-pentachlorobiphenyl (PCB-118) and 2,3,3',4,4',5-hexachlorobiphenyl (PCB-156) were compared in rats. The effect potencies were calculated based on administered dose and liver, adipose or plasma concentrations in female Sprague-Dawley rats 3 days after a single oral dose, relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Hepatic ethoxyresorufin-O-deethylase activity and gene expression of Cyp1a1, 1a2, 1b1 and aryl hydrocarbon receptor repressor in liver and peripheral blood lymphocytes were used as endpoints. Results show that plasma-based systemic REPs were generally within a half log range around the intake REPs for all congeners tested, except for 4-PeCDF. Together with our previously reported systemic REPs from a mouse study, these data do not warrant the use of systemic REPs as systemic TEFs for human risk assessment. However, further investigation for plasma-based systemic REPs for 4-PeCDF is desirable.
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Affiliation(s)
- Karin I van Ede
- Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80177, 3508 TD, Utrecht, The Netherlands,
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13
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van Ede KI, Aylward LL, Andersson PL, van den Berg M, van Duursen MBM. Tissue distribution of dioxin-like compounds: potential impacts on systemic relative potency estimates. Toxicol Lett 2013; 220:294-302. [PMID: 23680695 DOI: 10.1016/j.toxlet.2013.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/01/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
Abstract
Relative effect potencies (REPs) for dioxins and dioxin-like compounds based on tissue concentration or internal dose ((systemic)REPs) can be considered of high relevance for human risk assessment. Within the EU-project SYSTEQ, (systemic)REPs for 1,2,3,7,8-pentachlorodibenzodioxin (PeCDD), 2,3,4,7,8,-pentachlorodibenzofuran (4-PeCDF), 3,3',4,4',5-pentachlorobiphenyl (PCB 126), 2,3',4,4',5-pentachlorobiphenyl (PCB 118) and 2,3,3',4,4',5-hexachlorobiphenyl (PCB 156) were calculated based on a plasma, adipose tissue or liver concentration in Sprague Dawley rats and C57bl/6 mice three days after a single oral dose. Compound-specific distribution as well as differences in accumulation and elimination can influence the tissue concentration and thereby the relative potency estimate of a congener. Here, we show that distribution patterns are generally similar for the tested congeners between the SYSTEQ dataset and other studies using either a single dose or subchronic dosing. Furthermore, the responding concentration for TCDD in single dose studies is comparable to the responding concentrations reported in subchronic studies. In contrast with data for laboratory rodents, available distribution data for humans in the general population display little or no hepatic sequestration. Because hepatic sequestration due to CYP1A2 protein binding may affect the amount of congener that is bioavailable for the AhR to produce hepatic responses, estimates of relative potencies between congeners with differing degrees of hepatic sequestration based on hepatic responses may be misleading for application to human risk assessment. Therefore, extra-hepatic concentration in blood serum/plasma or adipose tissue together with a biological extra-hepatic response might give a more accurate prediction of the relative potency of a congener for human responses under environmental conditions.
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Affiliation(s)
- Karin I van Ede
- Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 104, 3584 CM Utrecht, The Netherlands.
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