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Van Der Ven LT, Van Ommeren P, Zwart EP, Gremmer ER, Hodemaekers HM, Heusinkveld HJ, van Klaveren JD, Rorije E. Dose Addition in the Induction of Craniofacial Malformations in Zebrafish Embryos Exposed to a Complex Mixture of Food-Relevant Chemicals with Dissimilar Modes of Action. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:47003. [PMID: 35394809 PMCID: PMC8992969 DOI: 10.1289/ehp9888] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 02/08/2022] [Accepted: 03/02/2022] [Indexed: 05/22/2023]
Abstract
BACKGROUND Humans are exposed to combinations of chemicals. In cumulative risk assessment (CRA), regulatory bodies such as the European Food Safety Authority consider dose addition as a default and sufficiently conservative approach. The principle of dose addition was confirmed previously for inducing craniofacial malformations in zebrafish embryos in binary mixtures of chemicals with either similar or dissimilar modes of action (MOAs). OBJECTIVES In this study, we explored a workflow to select and experimentally test multiple compounds as a complex mixture with each of the compounds at or below its no observed adverse effect level (NOAEL), in the same zebrafish embryo model. METHODS Selection of candidate compounds that potentially induce craniofacial malformations was done using in silico methods-structural similarity, molecular docking, and quantitative structure-activity relationships-applied to a database of chemicals relevant for oral exposure in humans via food (EuroMix inventory, n=1,598). A final subselection was made manually to represent different regulatory fields (e.g., food additives, industrial chemicals, plant protection products), different chemical families, and different MOAs. RESULTS A final selection of eight compounds was examined in the zebrafish embryo model, and craniofacial malformations were observed in embryos exposed to each of the compounds, thus confirming the developmental toxicity as predicted by the in silico methods. When exposed to a mixture of the eight compounds, each at its NOAEL, substantial craniofacial malformations were observed; according to a dose-response analysis, even embryos exposed to a 7-fold dilution of this mixture still exhibited a slight abnormal phenotype. The cumulative effect of the compounds in the mixture was in accordance with dose addition (added doses of the individual compounds after adjustment for relative potencies), despite different MOAs of the compounds involved. DISCUSSION This case study of a complex mixture inducing craniofacial malformations in zebrafish embryos shows that dose addition can adequately predicted the cumulative effect of a mixture of multiple substances at low doses, irrespective of the (expected) MOA. The applied workflow may be useful as an approach for CRA in general. https://doi.org/10.1289/EHP9888.
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Affiliation(s)
- Leo T.M. Van Der Ven
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | - Paul Van Ommeren
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | - Edwin P. Zwart
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | - Eric R. Gremmer
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | - Hennie M. Hodemaekers
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | - Harm J. Heusinkveld
- Centre for Health Protection, Dutch National Institute of Public Health and Environment (RIVM), Bilthoven, Netherlands
| | | | - Emiel Rorije
- Centre for Safety of Substances and Products, RIVM, Bilthoven, Netherlands
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Ham J, You S, Lim W, Song G. Etoxazole induces testicular malfunction in mice by dysregulating mitochondrial function and calcium homeostasis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 263:114573. [PMID: 33618463 DOI: 10.1016/j.envpol.2020.114573] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/23/2020] [Accepted: 04/08/2020] [Indexed: 06/12/2023]
Abstract
Epidemiological relationships between pesticide use and male infertility have been suggested for a long time. Etoxazole (ETX), an oxazoline pesticide, has been extensively used for pest eradication. It is considered relatively safe and has low mammalian toxicity because it specifically inhibits chitin synthesis. However, ETX may have toxic effects on the reproductive system. In this study, we examined the effects of ETX on the reproductive system using mouse testis cell lines (TM3 for Leydig cells and TM4 for Sertoli cells) and C57BL/6 male mice. We confirmed that ETX has anti-proliferative effects on the TM3 and TM4 cell lines. Moreover, ETX induced mitochondrial dysfunction and hampers calcium homeostasis. Western blot analysis of MAPK and Akt signaling cascades was performed to demonstrate the mode of action of ETX at a molecular level. Moreover, ETX induced misregulation of genes related to testicular function. Upon oral administration of ETX in C57BL/6 male mice, testis weight was reduced and transcriptional expression related to testis function was altered. These results indicate that ETX induces testicular toxicity by inducing mitochondrial dysfunction and calcium imbalance and regulating gene expression.
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Affiliation(s)
- Jiyeon Ham
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
| | - Seungkwon You
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea.
| | - Whasun Lim
- Department of Food and Nutrition, Kookmin University, Seoul, 02707, Republic of Korea.
| | - Gwonhwa Song
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea.
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Tebby C, van der Voet H, de Sousa G, Rorije E, Kumar V, de Boer W, Kruisselbrink JW, Bois FY, Faniband M, Moretto A, Brochot C. A generic PBTK model implemented in the MCRA platform: Predictive performance and uses in risk assessment of chemicals. Food Chem Toxicol 2020; 142:111440. [PMID: 32473292 DOI: 10.1016/j.fct.2020.111440] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/07/2020] [Accepted: 05/15/2020] [Indexed: 12/13/2022]
Abstract
Physiologically-based toxicokinetic (PBTK) models are important tools for in vitro to in vivo or inter-species extrapolations in health risk assessment of foodborne and non-foodborne chemicals. Here we present a generic PBTK model implemented in the EuroMix toolbox, MCRA 9 and predict internal kinetics of nine chemicals (three endocrine disrupters, three liver steatosis inducers, and three developmental toxicants), in data-rich and data-poor conditions, when increasingly complex levels of parametrization are applied. At the first stage, only QSAR models were used to determine substance-specific parameters, then some parameter values were refined by estimates from substance-specific or high-throughput in vitro experiments. At the last stage, elimination or absorption parameters were calibrated based on available in vivo kinetic data. The results illustrate that parametrization plays a capital role in the output of the PBTK model, as it can change how chemicals are prioritized based on internal concentration factors. In data-poor situations, estimates can be far from observed values. In many cases of chronic exposure, the PBTK model can be summarized by an external to internal dose factor, and interspecies concentration factors can be used to perform interspecies extrapolation. We finally discuss the implementation and use of the model in the MCRA risk assessment platform.
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Affiliation(s)
- Cleo Tebby
- INERIS, Unit Models for Ecotoxicology and Toxicology (METO), Verneuil-en-Halatte, France.
| | | | | | - Emiel Rorije
- RIVM, Centre for Safety of Substances and Products, Department for Consumers and Product Safety, P.O. Box 1, 3720, BA Bilthoven, Netherlands
| | - Vikas Kumar
- URV, Universitat Rovira i Virgili, C/ Països Catalans, nº 26, 43007, Tarragona (Tarragona- Catalonia), Spain
| | - Waldo de Boer
- Wageningen University & Research, Biometris, Wageningen, Netherlands
| | | | - Frédéric Y Bois
- INERIS, Unit Models for Ecotoxicology and Toxicology (METO), Verneuil-en-Halatte, France
| | - Moosa Faniband
- Division of Occupational and Environmental Medicine, Faculty of Medicine, Lund University, Sweden
| | - Angelo Moretto
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, Italy
| | - Céline Brochot
- INERIS, Unit Models for Ecotoxicology and Toxicology (METO), Verneuil-en-Halatte, France
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Fischer BC, Rotter S, Schubert J, Marx-Stoelting P, Solecki R. Recommendations for international harmonisation, implementation and further development of suitable scientific approaches regarding the assessment of mixture effects. Food Chem Toxicol 2020; 141:111388. [PMID: 32348816 DOI: 10.1016/j.fct.2020.111388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/02/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
Legal frameworks lay down requirements for risk assessment of combined exposure to multiple chemicals and their implementation where scientific methods are accepted by responsible authorities. In order to protect human health, an assessment of potential risks that might result from co-exposure to multiple chemical substances is requested by European legislation. Several approaches for risk assessment of mixtures of chemicals have been proposed, but none has been widely implemented in regulatory risk assessments, so far. EuroMix, an EU Horizon 2020 funded project, contributed to the improvement of internationally harmonised approaches for risk assessment of chemical mixtures. Based on in vitro and in silico tests, an integrated test strategy involving hazard and exposure assessment was developed and a web tool to conduct such assessments was provided. One further task within EuroMix was to make recommendations for international harmonisation, implementation and further development of suitable scientific approaches regarding the assessment of mixture effects. This paper briefly describes objectives and outcome of the EuroMix project as well as recent findings from OECD, WHO and EFSA addressing combined exposure to multiple chemicals. Building on this, five steps addressing further development needs and implementation of existing tools especially for risk managers and policy makers are proposed.
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Affiliation(s)
- Benjamin C Fischer
- Department Pesticides Safety, German Federal Institute for Risk Assessment - BfR, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Stefanie Rotter
- Department Pesticides Safety, German Federal Institute for Risk Assessment - BfR, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany.
| | - Jens Schubert
- Department Pesticides Safety, German Federal Institute for Risk Assessment - BfR, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Philip Marx-Stoelting
- Department Pesticides Safety, German Federal Institute for Risk Assessment - BfR, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Roland Solecki
- Department Pesticides Safety, German Federal Institute for Risk Assessment - BfR, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
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van der Voet H, Kruisselbrink JW, de Boer WJ, van Lenthe MS, van den Heuvel J(H, Crépet A, Kennedy MC, Zilliacus J, Beronius A, Tebby C, Brochot C, Luckert C, Lampen A, Rorije E, Sprong C, van Klaveren JD. The MCRA toolbox of models and data to support chemical mixture risk assessment. Food Chem Toxicol 2020; 138:111185. [DOI: 10.1016/j.fct.2020.111185] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/22/2020] [Accepted: 02/06/2020] [Indexed: 12/21/2022]
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Kennedy MC, Hart ADM, Kruisselbrink JW, van Lenthe M, de Boer WJ, van der Voet H, Rorije E, Sprong C, van Klaveren J. A retain and refine approach to cumulative risk assessment. Food Chem Toxicol 2020; 138:111223. [PMID: 32088251 DOI: 10.1016/j.fct.2020.111223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/07/2020] [Accepted: 02/17/2020] [Indexed: 12/27/2022]
Abstract
Mixtures of substances to which humans are exposed may lead to cumulative exposure and health effects. To study their effects, it is first necessary to identify a cumulative assessment group (CAG) of substances for risk assessment or hazard testing. Excluding substances from consideration before there is sufficient evidence may underestimate the risk. Conversely, including everything and treating the inevitable uncertainties using conservative assumptions is inefficient and may overestimate the risk, with an unknown level of protection. An efficient, transparent strategy is described to retain a large group, quantifying the uncertainty of group membership and other uncertainties. Iterative refinement of the CAG then focuses on adding information for the substances with high probability of contributing significantly to the risk. Probabilities can be estimated using expert opinion or derived from data on substance properties. An example is presented with 100 pesticides, in which the retain step identified a single substance to target refinement. Using an updated hazard characterisation for this substance reduced the mean exposure estimate from 0.43 to 0.28 μg kg-bw-1 day-1 and reduced the 99.99th percentile exposure from 24.9 to 5.1 μg kg-bw-1 day-1. Other retained substances contributed little to the risk estimates, even after accounting for uncertainty.
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Affiliation(s)
- Marc C Kennedy
- Fera Science Ltd, Sand Hutton, York, YO41 1LZ, United Kingdom.
| | - Andy D M Hart
- Fera Science Ltd, Sand Hutton, York, YO41 1LZ, United Kingdom
| | - Johannes W Kruisselbrink
- Wageningen University & Research, Biometrics, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Marco van Lenthe
- Wageningen University & Research, Biometrics, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Waldo J de Boer
- Wageningen University & Research, Biometrics, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Hilko van der Voet
- Wageningen University & Research, Biometrics, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Emiel Rorije
- RIVM, National Institute for Public Health and the Environment, The Netherlands, PO Box 1, 3720 BA, Bilthoven, the Netherlands
| | - Corinne Sprong
- RIVM, National Institute for Public Health and the Environment, The Netherlands, PO Box 1, 3720 BA, Bilthoven, the Netherlands
| | - Jacob van Klaveren
- RIVM, National Institute for Public Health and the Environment, The Netherlands, PO Box 1, 3720 BA, Bilthoven, the Netherlands
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