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Pecquet AM, Bridgwood K, Cowie D, Hofstra A, Wu Y, Whalley S, Webb SD. Data derived extrapolation factors (DDEFs) for rat to human interspecies extrapolation for the HPPD inhibitor mesotrione. Crit Rev Toxicol 2024:1-12. [PMID: 38869005 DOI: 10.1080/10408444.2024.2353174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/04/2024] [Indexed: 06/14/2024]
Abstract
In the risk assessment of agrochemicals, there has been a historical paucity of using data to refine the default adjustment factors, even though large datasets are available to support this. The current state of the science for addressing uncertainty regarding animal to human extrapolation (AFA) is to develop a "data-derived" adjustment factor (DDEF) to quantify such differences, if data are available. Toxicokinetic (TK) and toxicodynamic (TD) differences between species can be utilized for the DDEF, with human datasets being ideal yet rare. We identified a case for a currently registered herbicide, mesotrione, in which human TK and TD are available. This case study outlines an approach for the development of DDEFs using comparative human and animal data and based on an adverse outcome pathway (AOP) for inhibition of 4-hydroxyphenol pyruvate dioxygenase (HHPD). The calculated DDEF for rat to human extrapolation (AFA) for kinetics (AFAK = 2.5) was multiplied by the AFA for dynamics (AFAD = 0.3) resulting in a composite DDEF of ∼1 (AFA = 0.75). This reflects the AOP and available scientific evidence that humans are less sensitive than rats to the effects of HPPD inhibitors. Further analyses were conducted utilizing in vitro datasets from hepatocytes and liver cytosols and extrapolated to whole animal using in vitro to in vivo extrapolation (IVIVE) to support toxicodynamic extrapolation. The in vitro datasets resulted in the same AFAD as derived for in vivo data (AFAD = 0.3). These analyses demonstrate that a majority of the species differences are related to toxicodynamics. Future work with additional in vitro/in vivo datasets for other HPPD inhibitors and cell types will further support this result. This work demonstrates utilization of all available toxicokinetic and toxicodynamic data to replace default uncertainty factors for agrochemical human health risk assessment.
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Affiliation(s)
- Alison M Pecquet
- Product Safety, Syngenta Crop Protection LLC, Greensboro, NC, USA
| | - Katy Bridgwood
- Syngenta Jealott's Hill International Research Centre, Bracknell, UK
| | - David Cowie
- Syngenta Jealott's Hill International Research Centre, Bracknell, UK
| | | | - Yaoxing Wu
- Product Safety, Syngenta Crop Protection LLC, Greensboro, NC, USA
| | - Sarah Whalley
- Syngenta Jealott's Hill International Research Centre, Bracknell, UK
| | - Steven D Webb
- Syngenta Jealott's Hill International Research Centre, Bracknell, UK
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2
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Reale E, Zare Jeddi M, Paini A, Connolly A, Duca R, Cubadda F, Benfenati E, Bessems J, S Galea K, Dirven H, Santonen T, M Koch H, Jones K, Sams C, Viegas S, Kyriaki M, Campisi L, David A, Antignac JP, B Hopf N. Human biomonitoring and toxicokinetics as key building blocks for next generation risk assessment. ENVIRONMENT INTERNATIONAL 2024; 184:108474. [PMID: 38350256 DOI: 10.1016/j.envint.2024.108474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 12/15/2023] [Accepted: 02/01/2024] [Indexed: 02/15/2024]
Abstract
Human health risk assessment is historically built upon animal testing, often following Organisation for Economic Co-operation and Development (OECD) test guidelines and exposure assessments. Using combinations of human relevant in vitro models, chemical analysis and computational (in silico) approaches bring advantages compared to animal studies. These include a greater focus on the human species and on molecular mechanisms and kinetics, identification of Adverse Outcome Pathways and downstream Key Events as well as the possibility of addressing susceptible populations and additional endpoints. Much of the advancement and progress made in the Next Generation Risk Assessment (NGRA) have been primarily focused on new approach methodologies (NAMs) and physiologically based kinetic (PBK) modelling without incorporating human biomonitoring (HBM). The integration of toxicokinetics (TK) and PBK modelling is an essential component of NGRA. PBK models are essential for describing in quantitative terms the TK processes with a focus on the effective dose at the expected target site. Furthermore, the need for PBK models is amplified by the increasing scientific and regulatory interest in aggregate and cumulative exposure as well as interactions of chemicals in mixtures. Since incorporating HBM data strengthens approaches and reduces uncertainties in risk assessment, here we elaborate on the integrated use of TK, PBK modelling and HBM in chemical risk assessment highlighting opportunities as well as challenges and limitations. Examples are provided where HBM and TK/PBK modelling can be used in both exposure assessment and hazard characterization shifting from external exposure and animal dose/response assays to animal-free, internal exposure-based NGRA.
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Affiliation(s)
- Elena Reale
- Centre for Primary Care and Public Health (Unisanté), University of Lausanne, Switzerland
| | - Maryam Zare Jeddi
- National Institute for Public Health and the Environment (RIVM), the Netherlands
| | | | - Alison Connolly
- UCD Centre for Safety & Health at Work, School of Public Health, Physiotherapy, and Sports Science, University College Dublin, D04 V1W8, Dublin, Ireland for Climate and Air Pollution Studies, Physics, School of Natural Science and the Ryan Institute, National University of Ireland, University Road, Galway H91 CF50, Ireland
| | - Radu Duca
- Unit Environmental Hygiene and Human Biological Monitoring, Department of Health Protection, Laboratoire national de santé (LNS), 1, Rue Louis Rech, 3555 Dudelange, Luxembourg; Environment and Health, Department of Public Health and Primary Care, KU Leuven, Kapucijnenvoer 35, 3000 Leuven, Belgium
| | - Francesco Cubadda
- Istituto Superiore di Sanità - National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Emilio Benfenati
- Department of Environmental Health Sciences, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Via Mario Negri 2, 20156 Milano, Italy
| | - Jos Bessems
- VITO HEALTH, Flemish Institute for Technological Research, 2400 Mol, Belgium
| | - Karen S Galea
- Institute of Occupational Medicine (IOM), Research Avenue North, Riccarton, Edinburgh EH14 4AP, UK
| | - Hubert Dirven
- Department of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Tiina Santonen
- Finnish Institute of Occupational Health (FIOH), P.O. Box 40, FI-00032 Työterveyslaitos, Finland
| | - Holger M Koch
- Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany
| | - Kate Jones
- HSE - Health and Safety Executive, Harpur Hill, Buxton SK17 9JN, UK
| | - Craig Sams
- HSE - Health and Safety Executive, Harpur Hill, Buxton SK17 9JN, UK
| | - Susana Viegas
- NOVA National School of Public Health, Public Health Research Centre, Comprehensive Health Research Center, CHRC, NOVA University Lisbon, Lisbon, Portugal
| | - Machera Kyriaki
- Benaki Phytopathological Institute, 8, Stephanou Delta Street, 14561 Kifissia, Athens, Greece
| | - Luca Campisi
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy; Flashpoint srl, Via Norvegia 56, 56021 Cascina (PI), Italy
| | - Arthur David
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, F-35000 Rennes, France
| | | | - Nancy B Hopf
- Centre for Primary Care and Public Health (Unisanté), University of Lausanne, Switzerland.
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Melching-Kollmuss S, Bothe K, Charlton A, Gangadharan B, Ghaffari R, Jacobi S, Marty S, Marxfeld HA, McInnes EF, Sauer UG, Sheets LP, Strupp C, Tinwell H, Wiemann C, Botham PA, van Ravenzwaay B. Towards a science-based testing strategy to identify maternal thyroid hormone imbalance and neurodevelopmental effects in the progeny - Part IV: the ECETOC and CLE Proposal for a Thyroid Function-Related Neurodevelopmental Toxicity Testing and Assessment Scheme (Thyroid-NDT-TAS). Crit Rev Toxicol 2023; 53:339-371. [PMID: 37554099 DOI: 10.1080/10408444.2023.2231033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 08/10/2023]
Abstract
Following the European Commission Endocrine Disruptor Criteria, substances shall be considered as having endocrine disrupting properties if they (a) elicit adverse effects, (b) have endocrine activity, and (c) the two are linked by an endocrine mode-of-action (MoA) unless the MoA is not relevant for humans. A comprehensive, structured approach to assess whether substances meet the Endocrine Disruptor Criteria for the thyroid modality (EDC-T) is currently unavailable. Here, the European Centre for Ecotoxicology and Toxicology of Chemicals Thyroxine Task Force and CropLife Europe propose a Thyroid Function-Related Neurodevelopmental Toxicity Testing and Assessment Scheme (Thyroid-NDT-TAS). In Tier 0, before entering the Thyroid-NDT-TAS, all available in vivo, in vitro and in silico data are submitted to weight-of-evidence (WoE) evaluations to determine whether the substance of interest poses a concern for thyroid disruption. If so, Tier 1 of the Thyroid-NDT-TAS includes an initial MoA and human relevance assessment (structured by the key events of possibly relevant adverse outcome pathways) and the generation of supportive in vitro/in silico data, if relevant. Only if Tier 1 is inconclusive, Tier 2 involves higher-tier testing to generate further thyroid- and/or neurodevelopment-related data. Tier 3 includes the final MoA and human relevance assessment and an overarching WoE evaluation to draw a conclusion on whether, or not, the substance meets the EDC-T. The Thyroid-NDT-TAS is based on the state-of-the-science, and it has been developed to minimise animal testing. To make human safety assessments more accurate, it is recommended to apply the Thyroid-NDT-TAS during future regulatory assessments.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Ursula G Sauer
- Scientific Consultancy - Animal Welfare, Neubiberg, Germany
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Felter SP, Bhat VS, Botham PA, Bussard DA, Casey W, Hayes AW, Hilton GM, Magurany KA, Sauer UG, Ohanian EV. Assessing chemical carcinogenicity: hazard identification, classification, and risk assessment. Insight from a Toxicology Forum state-of-the-science workshop. Crit Rev Toxicol 2022; 51:653-694. [DOI: 10.1080/10408444.2021.2003295] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | - David A. Bussard
- U.S. Environmental Protection Agency, Office of the Science Advisor, Policy and Engagement, Washington, DC, USA
| | - Warren Casey
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - A. Wallace Hayes
- University of South Florida College of Public Health, Tampa, FL, USA
| | - Gina M. Hilton
- PETA Science Consortium International e.V., Stuttgart, Germany
| | | | | | - Edward V. Ohanian
- United States Environmental Protection Agency, Office of Water, Washington, DC, USA
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5
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Integrating toxicokinetics into toxicology studies and the human health risk assessment process for chemicals: Reduced uncertainty, better health protection. Regul Toxicol Pharmacol 2021; 128:105092. [PMID: 34863906 DOI: 10.1016/j.yrtph.2021.105092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 01/16/2023]
Abstract
The database of practical examples where toxicokinetic (TK) data has benefitted all stages of the human health risk assessment process are increasingly being published and accepted. This review aimed to highlight and summarise notable examples and to describe the "state of the art" in this field. The overall recommendation is that for any in vivo animal study conducted, measurements of TK should be very carefully considered for inclusion as the numerous benefits this brings continues to grow, particularly during the current march towards animal free toxicology testing and ambitions to eventually conduct human health risk assessments entirely based upon non-animal methods.
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Tan YM, Barton HA, Boobis A, Brunner R, Clewell H, Cope R, Dawson J, Domoradzki J, Egeghy P, Gulati P, Ingle B, Kleinstreuer N, Lowe K, Lowit A, Mendez E, Miller D, Minucci J, Nguyen J, Paini A, Perron M, Phillips K, Qian H, Ramanarayanan T, Sewell F, Villanueva P, Wambaugh J, Embry M. Opportunities and challenges related to saturation of toxicokinetic processes: Implications for risk assessment. Regul Toxicol Pharmacol 2021; 127:105070. [PMID: 34718074 DOI: 10.1016/j.yrtph.2021.105070] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 02/08/2023]
Abstract
Top dose selection for repeated dose animal studies has generally focused on identification of apical endpoints, use of the limit dose, or determination of a maximum tolerated dose (MTD). The intent is to optimize the ability of toxicity tests performed in a small number of animals to detect effects for hazard identification. An alternative approach, the kinetically derived maximum dose (KMD), has been proposed as a mechanism to integrate toxicokinetic (TK) data into the dose selection process. The approach refers to the dose above which the systemic exposures depart from being proportional to external doses. This non-linear external-internal dose relationship arises from saturation or limitation of TK process(es), such as absorption or metabolism. The importance of TK information is widely acknowledged when assessing human health risks arising from exposures to environmental chemicals, as TK determines the amount of chemical at potential sites of toxicological responses. However, there have been differing opinions and interpretations within the scientific and regulatory communities related to the validity and application of the KMD concept. A multi-stakeholder working group, led by the Health and Environmental Sciences Institute (HESI), was formed to provide an opportunity for impacted stakeholders to address commonly raised scientific and technical issues related to this topic and, more specifically, a weight of evidence approach is recommended to inform design and dose selection for repeated dose animal studies. Commonly raised challenges related to the use of TK data for dose selection are discussed, recommendations are provided, and illustrative case examples are provided to address these challenges or refute misconceptions.
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Affiliation(s)
- Yu-Mei Tan
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA
| | | | | | - Rachel Brunner
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA
| | | | - Rhian Cope
- Australian Pesticides and Veterinary Medicines Authority, Sydney, NSW, Australia
| | - Jeffrey Dawson
- U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Washington, DC, USA
| | | | - Peter Egeghy
- U.S. Environmental Protection Agency, Office of Research & Development, Durham, NC, USA
| | - Pankaj Gulati
- Australian Pesticides and Veterinary Medicines Authority, Sydney, NSW, Australia
| | - Brandall Ingle
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA
| | - Nicole Kleinstreuer
- National Toxicology Program, Interagency Center for the Evaluation of Alternative Toxicological Methods, Research Triangle Park, NC, USA
| | - Kelly Lowe
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Anna Lowit
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Elizabeth Mendez
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - David Miller
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Jeffrey Minucci
- U.S. Environmental Protection Agency, Office of Research & Development, Durham, NC, USA
| | - James Nguyen
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Alicia Paini
- European Commission, Joint Research Centre, Ispra, Italy
| | - Monique Perron
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Katherine Phillips
- U.S. Environmental Protection Agency, Office of Research & Development, Durham, NC, USA
| | - Hua Qian
- ExxonMobil Biomedical Sciences, Inc., Annandale, NJ, USA
| | | | - Fiona Sewell
- National Centre for the Replacement, Refinement, and Reduction of Animals in Research, London, UK
| | - Philip Villanueva
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - John Wambaugh
- U.S. Environmental Protection Agency, Office of Research & Development, Durham, NC, USA
| | - Michelle Embry
- Health and Environmental Sciences Institute, Washington DC, USA.
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7
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Machino S, Yokoyama Y, Egawa T, Satoh H, Miyajima K, Yoshida M, Asano S, Ozawa S. Case analysis of kinetics investigations in toxicity studies of pesticides to identify the nonlinearity of internal exposure and the influences of nonlinearity on the toxicological interpretation of pesticide residue. Regul Toxicol Pharmacol 2021; 124:104958. [PMID: 33991633 DOI: 10.1016/j.yrtph.2021.104958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 10/21/2022]
Abstract
The nonlinearity of internal exposure to 8 pesticides was investigated in toxicity studies using kinetics to identify nonlinearity visually and to investigate the influence of nonlinearity on toxicological evaluation. Data were obtained from risk assessment reports published by the Food Safety Commission (FSCJ). Nonlinearity was defined using 2 indicators: the lowest visual inflection point (LVIP) and the second lowest visual inflection point (SVIP) of kinetics by drawing a linear distribution chart. The area under the curve and 24-h urine concentrations were stable parameters used to identify the LVIP/SVIP. The sampling timing affected the blood concentrations, and the LVIP/SVIP was detected for 6 pesticides using the parent compounds or their metabolites as analytes. The subproportional nonlinearity was significant for these pesticides. The LVIP/SVIP values were consistent in the same species up to a 1-year period, but the values showed species-specific differences in several compounds. In all compounds found to be nonlinear, apical outcomes were observed at the SVIP or above. The presence of nonlinearity was recognized by the FSCJ. The recognition influenced their judgment of no-observed-adverse-effect levels (NOAELs) for carcinogenicity or health-based guidance values, indicating the importance of appropriate kinetics to identify the nonlinearity for toxicological evaluation of pesticide residue.
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Affiliation(s)
- Satoshi Machino
- Food Safety Commission, Cabinet Office of Japan. Akasaka Park Bld. 22F, 5-2-20 Akasaka, Minato-ku, Tokyo, 107-6122, Japan.
| | - Yoko Yokoyama
- Food Safety Commission, Cabinet Office of Japan. Akasaka Park Bld. 22F, 5-2-20 Akasaka, Minato-ku, Tokyo, 107-6122, Japan.
| | - Toyohiro Egawa
- Food Safety Commission, Cabinet Office of Japan. Akasaka Park Bld. 22F, 5-2-20 Akasaka, Minato-ku, Tokyo, 107-6122, Japan.
| | - Hiroshi Satoh
- Faculty of Agriculture, Iwate University. 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan.
| | - Katsuhiro Miyajima
- Department of Nutritional Science and Food Safety, Faculty of Applied Bio-Science, Tokyo University of Agriculture. 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
| | - Midori Yoshida
- Food Safety Commission, Cabinet Office of Japan. Akasaka Park Bld. 22F, 5-2-20 Akasaka, Minato-ku, Tokyo, 107-6122, Japan.
| | - Satoshi Asano
- Department of Pharmaceutical Science, International University of Health and Welfare. 2600-1 Kitakanemaru, Ohtawara, Tochigi, 324-8501, Japan.
| | - Shogo Ozawa
- School of Pharmacy, Iwate Medical University 2-1-1 Nishitokuta, Yahaba-cho, Shiwa-gun, Iwate, 028-3684, Japan.
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Heringa MB, Cnubben NHP, Slob W, Pronk MEJ, Muller A, Woutersen M, Hakkert BC. Rebuttal to the letters to the editors by Terry et al. and Sewell et al. regarding. Regul Toxicol Pharmacol 2020; 118:104803. [PMID: 33091463 DOI: 10.1016/j.yrtph.2020.104803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/08/2020] [Indexed: 11/16/2022]
Affiliation(s)
- Minne B Heringa
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
| | - Nicole H P Cnubben
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
| | - Wout Slob
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
| | - Marja E J Pronk
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
| | - Andre Muller
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
| | - Marjolijn Woutersen
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands.
| | - Betty C Hakkert
- National Institute for Public Health and the Environment (RIVM), Centre for Safety of Substances and Products (VSP), Bilthoven, the Netherlands
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Slob W, Zeilmaker MJ, Hoogenveen RT. The Relationship Between Internal and External Dose: Some General Results Based on a Generic Compartmental Model. Toxicol Sci 2020; 177:60-70. [PMID: 32514576 DOI: 10.1093/toxsci/kfaa082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Statements on how the internal-to-external-dose (IED) relationship looks like are often based on qualitative toxicokinetic arguments. For example, the recently proposed kinetically derived maximum dose (KMD) states that the IED relationship must have an inflection point, due to saturation of underlying processes like metabolism or absorption. However, such statements lack a solid quantitative foundation. Therefore, we derived expressions for the IED relationship for a number of scenarios based on a generic compartmental model involving saturation. The scenarios included repeated or single dose, and saturable metabolism or saturable absorption. For some of these scenarios, an explicit expression for the IED relationship can be derived, for others only implicit expressions can be established, which need to be evaluated numerically. The results show that saturable processes will lead to an IED relationship that is nonlinear over the whole dose range, ie, it can be approximated by a linear relationship at the lower end, whereas the approximation will become gradually poorer with increasing doses. The finding that saturation does not lead to an inflection point in the IED relationship, as assumed in the KMD, implies that the KMD is not a valid approach for selecting the top dose in toxicological studies. An additional use of our results is that the derived explicit expressions of the IED relationship can be fitted to IED data, and, possibly, for extrapolation outside the observed dose range.
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Affiliation(s)
- Wout Slob
- National Institute for Public Health and the Environment (RIVM), VPZ, 3720 BA Bilthoven, The Netherlands
| | - Marco J Zeilmaker
- National Institute for Public Health and the Environment (RIVM), VPZ, 3720 BA Bilthoven, The Netherlands
| | - Rudolf T Hoogenveen
- National Institute for Public Health and the Environment (RIVM), VPZ, 3720 BA Bilthoven, The Netherlands
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10
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Bartels M, Brown C, Chung G, Chan M, Terry C, Gehen S, Corvaro M. Review of the pharmacokinetics and metabolism of triclopyr herbicide in mammals: Impact on safety assessments. Regul Toxicol Pharmacol 2020; 116:104714. [PMID: 32640299 DOI: 10.1016/j.yrtph.2020.104714] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/30/2020] [Accepted: 06/08/2020] [Indexed: 11/16/2022]
Abstract
A review of pharmacokinetic and metabolism studies show that triclopyr is well absorbed from the oral route in numerous species (≥80%), primarily as parent compound. Absorption is quite rapid in rats, dogs and human volunteers. Plasma or blood clearance is also rapid (t1/2 3-9 h), except for dog (12-96 h). Systemic exposure is not dose-proportional: in the rat above 20 mg/kg (dietary) or between 3 and 60 mg/kg (gavage), or in dogs above 5 mg/kg, with systemic exposure in human more comparable to rat than dog. Triclopyr is highly bound to protein in rat, dog and human plasma (≥97% at or below 7 μg/mL), indicating that species differences in systemic exposure are not due to differences in the free fraction of this test material in plasma. An in vitro flux study in renal proximal tubule cells showed that net renal transport of triclopyr is in the direction of secretion in rat and human donors, while reabsorption predominated in the dog, possibly via organic anion transporters such as OAT1/3. These results fit well into the framework of utilizing metabolism and toxicokinetics across species and exposure levels to allow for toxicity testing in the most relevant species as well as at proper dose levels.
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Affiliation(s)
| | | | - Git Chung
- Newcells Biotech, Newcastle Upon Tyne, UK
| | | | | | - Sean Gehen
- Corteva Agriscience™, Indianapolis, IN, USA
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11
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Heringa MB, Cnubben NH, Slob W, Pronk ME, Muller A, Woutersen M, Hakkert BC. Use of the kinetically-derived maximum dose concept in selection of top doses for toxicity studies hampers proper hazard assessment and risk management. Regul Toxicol Pharmacol 2020; 114:104659. [DOI: 10.1016/j.yrtph.2020.104659] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 04/02/2020] [Accepted: 04/11/2020] [Indexed: 01/02/2023]
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12
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The ADME profile of the fungicide tricyclazole in rodent via the oral route: A critical review for human health safety assessment. Regul Toxicol Pharmacol 2019; 108:104438. [DOI: 10.1016/j.yrtph.2019.104438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/27/2019] [Accepted: 08/02/2019] [Indexed: 12/17/2022]
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13
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Gehen S, Corvaro M, Jones J, Ma M, Yang Q. Challenges and Opportunities in the Global Regulation of Crop Protection Products. Org Process Res Dev 2019. [DOI: 10.1021/acs.oprd.9b00284] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sean Gehen
- Crop Protection Regulatory Sciences, Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Marco Corvaro
- Crop Protection Regulatory Sciences, Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Jennifer Jones
- Product Design & Process R&D, Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Mingming Ma
- Crop Protection Regulatory Sciences, Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
| | - Qiang Yang
- Product Design & Process R&D, Corteva Agriscience, 9330 Zionsville Road, Indianapolis, Indiana 46268, United States
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Cooper AB, Aggarwal M, Bartels MJ, Morriss A, Terry C, Lord GA, Gant TW. PBTK model for assessment of operator exposure to haloxyfop using human biomonitoring and toxicokinetic data. Regul Toxicol Pharmacol 2018; 102:1-12. [PMID: 30543831 DOI: 10.1016/j.yrtph.2018.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/03/2018] [Accepted: 12/06/2018] [Indexed: 11/18/2022]
Abstract
Physiologically-based toxicokinetic (PBTK) models are mathematical representations of chemical absorption, distribution, metabolism and excretion (ADME) in animals. Each parameter in a PBTK model describes a physiological, physicochemical or biochemical process that affects ADME. Distributions can be assigned to the model parameters to describe population variability and uncertainty. In this study to assess potential crop sprayer operator exposure to the herbicide haloxyfop, a permeability-limited PBTK model was constructed with parameter uncertainty and variability, and calibrated using Bayesian analysis via Markov chain Monte Carlo methods. A hierarchical statistical model was developed to reconstruct operator exposure using available measurement data: experimentally determined octanol/water partition coefficient, mouse and human toxicokinetic data as well as human biomonitoring data from seven operators who participated in a field study. A chemical risk assessment was performed by comparing the estimated systemic exposure to the acceptable operator exposure level (AOEL). The analysis suggested that in one of the seven operators, the model estimates systemic exposure to haloxyfop of 49.04 ± 10.19 SD μg/kg bw in relation to an AOEL of 5.0 μg/kg bw/day. This does not represent a safety concern as this predicted exposure is well within the 100-fold uncertainty factor applied to the No Observed Adverse Effect Level (NOAEL) in animals. In addition, given the availability of human toxicokinetic data, the 10x uncertainty factor for interspecies differences in ADME could be reduced (EFSA, 2006). Thus the AOEL could potentially be raised tenfold from 5.0 to 50.0 μg/kg bw/day.
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Affiliation(s)
- Alexander B Cooper
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Harwell Campus, Didcot, OX11 0RQ, UK.
| | - Manoj Aggarwal
- Dow AgroSciences, 3B Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, UK
| | - Michael J Bartels
- Dow AgroSciences, 3B Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, UK
| | - Alistair Morriss
- Dow AgroSciences, 3B Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, UK
| | - Claire Terry
- Dow AgroSciences, 3B Park Square, Milton Park, Abingdon, Oxfordshire, OX14 4RN, UK
| | - Gwyn A Lord
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Harwell Campus, Didcot, OX11 0RQ, UK
| | - Timothy W Gant
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Harwell Campus, Didcot, OX11 0RQ, UK; Kings College London, Department of Analytical, Environmental & Forensic Sciences, James Clerk Maxwell Building 57 Waterloo Road, London, SE1 8WA, UK.
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15
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Finding synergies for 3Rs – Toxicokinetics and read-across: Report from an EPAA partners' Forum. Regul Toxicol Pharmacol 2018; 99:5-21. [DOI: 10.1016/j.yrtph.2018.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/17/2018] [Accepted: 08/16/2018] [Indexed: 01/11/2023]
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16
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The current status of exposure-driven approaches for chemical safety assessment: A cross-sector perspective. Toxicology 2017; 389:109-117. [DOI: 10.1016/j.tox.2017.07.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/27/2017] [Accepted: 07/31/2017] [Indexed: 12/20/2022]
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17
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Bevan R, Brown T, Matthies F, Sams C, Jones K, Hanlon J, La Vedrine M. Human biomonitoring data collection from occupational exposure to pesticides. ACTA ACUST UNITED AC 2017. [DOI: 10.2903/sp.efsa.2017.en-1185] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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18
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Brownbill P, Chernyavsky I, Bottalico B, Desoye G, Hansson S, Kenna G, Knudsen LE, Markert UR, Powles-Glover N, Schneider H, Leach L. An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy. Reprod Toxicol 2016; 64:191-202. [PMID: 27327413 DOI: 10.1016/j.reprotox.2016.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/23/2016] [Accepted: 06/07/2016] [Indexed: 12/14/2022]
Abstract
The human placenta is a critical life-support system that nourishes and protects a rapidly growing fetus; a unique organ, species specific in structure and function. We consider the pressing challenge of providing additional advice on the safety of prescription medicines and environmental exposures in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, "PlaNet", will bridge academia, industry and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice.
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Affiliation(s)
- Paul Brownbill
- Maternal and Fetal Health Research Centre, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK; Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
| | - Igor Chernyavsky
- School of Mathematics, University of Manchester, Manchester, UK.
| | - Barbara Bottalico
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria.
| | - Stefan Hansson
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | | | - Lisbeth E Knudsen
- Department of Public Health, Faculty Of Health Sciences, University of Copenhagen, Denmark.
| | - Udo R Markert
- Placenta-Labor Laboratory, Department of Obstetrics, Friedrich Schiller University, D-07740, Jena, Germany.
| | - Nicola Powles-Glover
- Reproductive, Development and Paediatric Centre of Excellence, AstraZeneca, Mereside, Alderley Park, Alderley Edge SK10 4TG, UK.
| | - Henning Schneider
- Department of Obstetrics and Gynecology, Inselspital, University of Bern, Switzerland.
| | - Lopa Leach
- Molecular Cell Biology & Development, School of Life Sciences, Faculty of Medicine & Health Sciences, University of Nottingham, UK.
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