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Gonnabathula P, Choi MK, Li M, Kabadi SV, Fairman K. Utility of life stage-specific chemical risk assessments based on New Approach Methodologies (NAMs). Food Chem Toxicol 2024; 190:114789. [PMID: 38844066 DOI: 10.1016/j.fct.2024.114789] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 05/17/2024] [Accepted: 06/03/2024] [Indexed: 06/17/2024]
Abstract
The safety assessments for chemicals targeted for use or expected to be exposed to specific life stages, including infancy, childhood, pregnancy and lactation, and geriatrics, need to account for extrapolation of data from healthy adults to these populations to assess their human health risk. However, often adequate and relevant toxicity or pharmacokinetic (PK) data of chemicals in specific life stages are not available. For such chemicals, New Approach Methodologies (NAMs), such as physiologically based pharmacokinetic (PBPK) modeling, biologically based dose response (BBDR) modeling, in vitro to in vivo extrapolation (IVIVE), etc. can be used to understand the variability of exposure and effects of chemicals in specific life stages and assess their associated risk. A life stage specific PBPK model incorporates the physiological and biochemical changes associated with each life stage and simulates their impact on the absorption, distribution, metabolism, and elimination (ADME) of these chemicals. In our review, we summarize the parameterization of life stage models based on New Approach Methodologies (NAMs) and discuss case studies that highlight the utility of a life stage based PBPK modeling for risk assessment. In addition, we discuss the utility of artificial intelligence (AI)/machine learning (ML) and other computational models, such as those based on in vitro data, as tools for estimation of relevant physiological or physicochemical parameters and selection of model. We also discuss existing gaps in the available toxicological datasets and current challenges that need to be overcome to expand the utility of NAMs for life stage-specific chemical risk assessment.
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Affiliation(s)
- Pavani Gonnabathula
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Me-Kyoung Choi
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Miao Li
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA
| | - Shruti V Kabadi
- Center for Food Safety and Applied Nutrition (CFSAN), US Food and Drug Administration (FDA), College Park, MD, 20740, USA
| | - Kiara Fairman
- Division of Biochemical Toxicology, National Center for Toxicological Research (NCTR), US Food and Drug Administration (FDA), Jefferson, AR, 72079, USA.
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2
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Huang Z, Sun Z, Liu J, Ju X, Xia H, Yang Y, Chen K, Wang Q. Insect transient receptor potential vanilloid channels as potential targets of insecticides. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 148:104899. [PMID: 37531974 DOI: 10.1016/j.dci.2023.104899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
Chordotonal organs are miniature sensory organs present in insects. Chordotonal organs depend on transient receptor potential (TRP) channels. Transient receptor potential vanilloid (TRPV) channels are the only TRPs identified that can act as targets of insecticides. By binding with TRPV channels, insecticides targeting the chordotonal organs trigger the inflow of calcium ions, resulting in abnormal function of the chordotonal organ to achieve the goal of eliminating pests. TRPV channels are highly expressed in various developmental stages and tissue parts of insects and play an important role in the whole life history of insects. In this review, we will discuss the structure and types of TRPV channels as well as their genetic relationships in different species. We also systematically reviewed the recent progress of TRPV channels as insecticide targets, demonstrating that TRPV channels can be used as the target of new high-efficiency insecticides.
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Affiliation(s)
- Zengqing Huang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Zhonghe Sun
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Jiayi Liu
- School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, PR China
| | - Xiaoli Ju
- School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, PR China
| | - Hengchuan Xia
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Yanhua Yang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China
| | - Qiang Wang
- School of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu, PR China.
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3
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Loccisano AE, Freeman E, Doi A, Frericks M, Fegert I, Fabian E, Riffle B. A new approach methodology using kinetically-derived maximum dose levels in risk assessment - A case study with afidopyropen. Regul Toxicol Pharmacol 2023:105429. [PMID: 37277056 DOI: 10.1016/j.yrtph.2023.105429] [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: 04/05/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/07/2023]
Abstract
We present a case study for afidopyropen (AF; insecticide) to characterize chronic dietary human health risk using a Risk 21-based approach. Our objective is to use a well-tested pesticidal active ingredient (AF) to show how a new approach methodology (NAM), using the kinetically-derived maximum dose (KMD) and with far less animal testing, can reliably identify a health-protective point of departure (PoD) for chronic dietary human health risk assessments (HHRA). Chronic dietary HHRA involves evaluation of both hazard and exposure information to characterize risk. Although both are important, emphasis has been placed on a checklist of required toxicological studies for hazard characterization, with human exposure information only considered after evaluation of hazard data. Most required studies are not used to define the human endpoint for HHRA. The information presented demonstrates a NAM that uses the KMD determined by saturation of a metabolic pathway, which can be used as an alternative POD. In these cases, the full toxicological database may not need to be generated. Demonstration that the compound is not genotoxic and that the KMD is protective of adverse effects in 90-day oral rat and reproductive/developmental studies is sufficient to support the use of the KMD as an alternative POD.
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Affiliation(s)
| | | | - Adriana Doi
- BASF Corporation Research Triangle Park, NC, 27709, USA
| | - Markus Frericks
- BASF SE Regulatory Toxicology Crop Protection, Limburgerhof, Germany
| | - Ivana Fegert
- BASF SE Regulatory Toxicology Crop Protection, Limburgerhof, Germany
| | - Eric Fabian
- BASF SE Experimental Toxicology and Ecology, Ludwigshafen, Germany
| | - Brandy Riffle
- BASF Corporation Research Triangle Park, NC, 27709, USA.
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4
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Hoer D, Barton HA, Paini A, Bartels M, Ingle B, Domoradzki J, Fisher J, Embry M, Villanueva P, Miller D, Nguyen J, Zhang Q, Edwards SW, Tan YM. Predicting nonlinear relationships between external and internal concentrations with physiologically based pharmacokinetic modeling. Toxicol Appl Pharmacol 2022; 440:115922. [PMID: 35176293 PMCID: PMC10519136 DOI: 10.1016/j.taap.2022.115922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/19/2022] [Accepted: 02/10/2022] [Indexed: 11/20/2022]
Abstract
Although external concentrations are more readily quantified and often used as the metric for regulating and mitigating exposures to environmental chemicals, the toxicological response to an environmental chemical is more directly related to its internal concentrations than the external concentration. The processes of absorption, distribution, metabolism, and excretion (ADME) determine the quantitative relationship between the external and internal concentrations, and these processes are often susceptible to saturation at high concentrations, which can lead to nonlinear changes in internal concentrations that deviate from proportionality. Using generic physiologically-based pharmacokinetic (PBPK) models, we explored how saturable absorption or clearance influence the shape of the internal to external concentration (IEC) relationship. We used the models for hypothetical chemicals to show how differences in kinetic parameters can impact the shape of an IEC relationship; and models for styrene and caffeine to explore how exposure route, frequency, and duration impact the IEC relationships in rat and human exposures. We also analyzed available plasma concentration data for 2,4-dichlorophenoxyacetic acid to demonstrate how a PBPK modeling approach can be an alternative to common statistical methods for analyzing dose proportionality. A PBPK modeling approach can be a valuable tool used in the early stages of a chemical safety assessment program to optimize the design of longer-term animal toxicity studies or to interpret study results.
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Affiliation(s)
- Daniel Hoer
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA
| | | | - Alicia Paini
- European Commission, Joint Research Centre, Ispra, Italy.
| | | | - Brandall Ingle
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA
| | | | | | - Michelle Embry
- Health and Environmental Sciences Institute, Washington, DC, USA
| | - Philip Villanueva
- 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
| | - James Nguyen
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC, USA
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | | | - Yu-Mei Tan
- U.S. Environmental Protection Agency, Office of Pesticide Programs, Durham, NC, USA.
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5
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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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Loccisano AE, Freeman E, Riffle B, Doi A, Frericks M, Fegert I, Fabian E. Afidopyropen: Challenges and impact of a toxicokinetic study designed to identify a point of inflection from dose-proportionality. Regul Toxicol Pharmacol 2021; 124:104962. [PMID: 34019964 DOI: 10.1016/j.yrtph.2021.104962] [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: 01/13/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 11/30/2022]
Abstract
Afidopyropen is an insecticide that acts as a transient receptor potential vanilloid subtype (TRPV) channel modulator in chordotonal organs of target insects and has been assessed for a wide range of toxicity endpoints including chronic toxicity and carcinogenicity in rats and mice. The current study evaluates the toxicokinetic properties of afidopyropen and its plasma metabolites in rats at dose levels where the pharmacokinetics (PK) are linear and nonlinear in an attempt to identify a point of inflection. Based on the results of this study and depending on the analysis method used, the kinetically derived maximum dose (KMD) is estimated to be between 2.5 and 12.5 mg/kg bw/d with linearity observed at doses below 2.5 mg/kg bw/d. A defined point of inflection could not be determined. These data demonstrate that consideration of PK is critical for improving the dose-selection in toxicity studies as well as to enhance human relevance of the interpretation of animal toxicity studies. The study also demonstrates the technical difficulty in obtaining a defined point of inflection from in vivo PK data.
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Affiliation(s)
| | | | - Brandy Riffle
- BASF Corporation, Research Triangle Park, NC, 27709, USA
| | - Adriana Doi
- BASF Corporation, Research Triangle Park, NC, 27709, USA
| | - Markus Frericks
- BASF SE Experimental Toxicology and Ecology, Ludwigshafen, Germany
| | - Ivana Fegert
- BASF SE Experimental Toxicology and Ecology, Ludwigshafen, Germany
| | - Eric Fabian
- BASF SE Experimental Toxicology and Ecology, Ludwigshafen, Germany.
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