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Huisinga M, Bertrand L, Chamanza R, Damiani I, Engelhardt J, Francke S, Freyberger A, Harada T, Harleman J, Kaufmann W, Keane K, Köhrle J, Lenz B, Marty MS, Melching-Kollmuss S, Palazzi X, Pohlmeyer-Esch G, Popp A, Rosol TJ, Strauss V, Van den Brink-Knol H, Wood CE, Yoshida M. Adversity Considerations for Thyroid Follicular Cell Hypertrophy and Hyperplasia in Nonclinical Toxicity Studies: Results From the 6th ESTP International Expert Workshop. Toxicol Pathol 2021; 48:920-938. [PMID: 33334259 DOI: 10.1177/0192623320972009] [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] [Indexed: 12/18/2022]
Abstract
The European Society of Toxicologic Pathology organized an expert workshop in May 2018 to address adversity considerations related to thyroid follicular cell hypertrophy and/or hyperplasia (FCHH), which is a common finding in nonclinical toxicity studies that can have important implications for risk assessment of pharmaceuticals, food additives, and environmental chemicals. The broad goal of the workshop was to facilitate better alignment in toxicologic pathology and regulatory sciences on how to determine adversity of FCHH. Key objectives were to describe common mechanisms leading to thyroid FCHH and potential functional consequences; provide working criteria to assess adversity of FCHH in context of associated findings; and describe additional methods and experimental data that may influence adversity determinations. The workshop panel was comprised of representatives from the European Union, Japan, and the United States. Participants shared case examples illustrating issues related to adversity assessments of thyroid changes. Provided here are summary discussions, key case presentations, and panel recommendations. This information should increase consistency in the interpretation of adverse changes in the thyroid based on pathology findings in nonclinical toxicity studies, help integrate new types of biomarker data into the review process, and facilitate a more systematic approach to communicating adversity determinations in toxicology reports.
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Affiliation(s)
| | - Lise Bertrand
- 57146Charles River Laboratories, Saint-Germain-Nuelles, France
| | - Ronnie Chamanza
- 50148Janssen Pharmaceutical Companies of Johnson & Johnson, Beerse, Belgium
| | | | | | - Sabine Francke
- Center for Food Safety and Applied Nutrition (CFSAN), 4137US Food and Drug Administration, College Park, MD, USA
| | | | | | | | | | | | - Josef Köhrle
- 72217Charité University Medicine Berlin, Berlin, Germany
| | - Barbara Lenz
- Roche Pharma Research and Development, Basel, Switzerland
| | - M Sue Marty
- 540144The Dow Chemical Company, Midland, MI, USA
| | | | | | | | | | | | | | | | - Charles E Wood
- 6893Boehringer Ingelheim Pharmaceuticals Inc, Ridgefield, CT, USA
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Martin P, Bladier C, Meek B, Bruyere O, Feinblatt E, Touvier M, Watier L, Makowski D. Weight of Evidence for Hazard Identification: A Critical Review of the Literature. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:076001. [PMID: 30024384 PMCID: PMC6108859 DOI: 10.1289/ehp3067] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/22/2018] [Accepted: 05/25/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND Transparency when documenting and assessing weight of evidence (WOE) has been an area of increasing focus for national and international health agencies. OBJECTIVE The objective of this work was to conduct a critical review of WOE analysis methods as a basis for developing a practical framework for considering and assessing WOE in hazard identification in areas of application at the French Agency for Food, Environmental and Occupational Health and Safety (ANSES). METHODS Based on a review of the literature and directed requests to 63 international and national agencies, 116 relevant articles and guidance documents were selected. The WOE approaches were assessed based on three aspects: the extent of their prescriptive nature, their purpose-specific relevance, and their ease of implementation. RESULTS Twenty-four approaches meeting the specified criteria were identified from selected reviewed documents. Most approaches satisfied one or two of the assessed considerations, but not all three. The approaches were grouped within a practical framework comprising the following four stages: (1) planning the assessment, including scoping, formulating the question, and developing the assessment method; (2) establishing lines of evidence (LOEs), including identifying and selecting studies, assessing their quality, and integrating with studies of similar type; (3) integrating the LOEs to evaluate WOE; and (4) presenting conclusions. DISCUSSION Based on the review, considerations for selecting methods for a wide range of applications are proposed. Priority areas for further development are identified. https://doi.org/10.1289/EHP3067.
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Affiliation(s)
- Pierre Martin
- French Agricultural Research Centre for International Development (CIRAD), Agroecology and sustainable intensification of annual crops (UPR AIDA), Montpellier, France
- AIDA, CIRAD, Montpellier University, Montpellier, France
| | - Claire Bladier
- French Agency for Food, Environmental and Occupational Health and Safety (ANSES), Maisons-Alfort, France
| | - Bette Meek
- McLaughlin Center for Risk Science, University of Ottawa, Ottawa, Canada
| | - Olivier Bruyere
- WHO Collaborating Center for Public Health Aspects of Musculo-Skeletal Health and Aging, Department of Public Health, Epidemiology, and Health Economics, University of Liège, Liège, Belgium
| | - Eve Feinblatt
- French Agency for Food, Environmental and Occupational Health and Safety (ANSES), Maisons-Alfort, France
| | - Mathilde Touvier
- Nutritional Epidemiology Research Team (EREN), Center of Research in Epidemiology and Statistics, Sorbonne Paris Cité (CRESS), Institute for Health and Medical Research (INSERM, U1153), French National Institute of Research for Agriculture (INRA, U1125), National Conservatory of Arts and Crafts (CNAM), Paris University, Bobigny, France
| | - Laurence Watier
- Biostatistics, Biomathematics, Pharmacoepidemiology and Infectious Diseases (B2PHI), INSERM, UVSQ, Pasteur Institute, University of Paris-Saclay, Paris, France
| | - David Makowski
- UMR Agronomy, INRA, AgroParisTech, University of Paris-Saclay, Thiverval-Grignon, France
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Corton JC, Peters JM, Klaunig JE. The PPARα-dependent rodent liver tumor response is not relevant to humans: addressing misconceptions. Arch Toxicol 2017; 92:83-119. [PMID: 29197930 DOI: 10.1007/s00204-017-2094-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/12/2017] [Indexed: 12/17/2022]
Abstract
A number of industrial chemicals and therapeutic agents cause liver tumors in rats and mice by activating the nuclear receptor peroxisome proliferator-activated receptor α (PPARα). The molecular and cellular events by which PPARα activators induce rodent hepatocarcinogenesis have been extensively studied elucidating a number of consistent mechanistic changes linked to the increased incidence of liver neoplasms. The weight of evidence relevant to the hypothesized mode of action (MOA) for PPARα activator-induced rodent hepatocarcinogenesis is summarized here. Chemical-specific and mechanistic data support concordance of temporal and dose-response relationships for the key events associated with many PPARα activators. The key events (KE) identified in the MOA are PPARα activation (KE1), alteration in cell growth pathways (KE2), perturbation of hepatocyte growth and survival (KE3), and selective clonal expansion of preneoplastic foci cells (KE4), which leads to the apical event-increases in hepatocellular adenomas and carcinomas (KE5). In addition, a number of concurrent molecular and cellular events have been classified as modulating factors, because they potentially alter the ability of PPARα activators to increase rodent liver cancer while not being key events themselves. These modulating factors include increases in oxidative stress and activation of NF-kB. PPARα activators are unlikely to induce liver tumors in humans due to biological differences in the response of KEs downstream of PPARα activation. This conclusion is based on minimal or no effects observed on cell growth pathways and hepatocellular proliferation in human primary hepatocytes and absence of alteration in growth pathways, hepatocyte proliferation, and tumors in the livers of species (hamsters, guinea pigs and cynomolgus monkeys) that are more appropriate human surrogates than mice and rats at overlapping dose levels. Despite this overwhelming body of evidence and almost universal acceptance of the PPARα MOA and lack of human relevance, several reviews have selectively focused on specific studies that, as discussed, contradict the consensus opinion and suggest uncertainty. In the present review, we systematically address these most germane suggested weaknesses of the PPARα MOA.
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Affiliation(s)
- J Christopher Corton
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, 109 T.W. Alexander Dr, MD-B105-03, Research Triangle Park, NC, 27711, USA.
| | - Jeffrey M Peters
- The Department of Veterinary and Biomedical Sciences and Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, 16803, USA
| | - James E Klaunig
- Department of Environmental Health, Indiana University, Bloomington, IN, 47402, USA
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Bal-Price A, Lein PJ, Keil KP, Sethi S, Shafer T, Barenys M, Fritsche E, Sachana M, Meek MEB. Developing and applying the adverse outcome pathway concept for understanding and predicting neurotoxicity. Neurotoxicology 2016; 59:240-255. [PMID: 27212452 DOI: 10.1016/j.neuro.2016.05.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 05/13/2016] [Accepted: 05/13/2016] [Indexed: 12/12/2022]
Abstract
The Adverse Outcome Pathway (AOP) concept has recently been proposed to support a paradigm shift in regulatory toxicology testing and risk assessment. This concept is similar to the Mode of Action (MOA), in that it describes a sequence of measurable key events triggered by a molecular initiating event in which a stressor interacts with a biological target. The resulting cascade of key events includes molecular, cellular, structural and functional changes in biological systems, resulting in a measurable adverse outcome. Thereby, an AOP ideally provides information relevant to chemical structure-activity relationships as a basis for predicting effects of structurally similar compounds. AOPs could potentially also form the basis for qualitative and quantitative predictive modeling of the human adverse outcome resulting from molecular initiating or other key events for which higher-throughput testing methods are available or can be developed. A variety of cellular and molecular processes are known to be critical for normal function of the central (CNS) and peripheral nervous systems (PNS). Because of the biological and functional complexity of the CNS and PNS, it has been challenging to establish causative links and quantitative relationships between key events that comprise the pathways leading from chemical exposure to an adverse outcome in the nervous system. Following introduction of the principles of MOA and AOPs, examples of potential or putative adverse outcome pathways specific for developmental or adult neurotoxicity are summarized and aspects of their assessment considered. Their possible application in developing mechanistically informed Integrated Approaches to Testing and Assessment (IATA) is also discussed.
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Affiliation(s)
- Anna Bal-Price
- European Commission Joint Research Centre, Institute for Health and Consumer Protection, Ispra, Italy.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Kimberly P Keil
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Sunjay Sethi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Timothy Shafer
- Integrated Systems Toxicology Division, Office of Research and Development, U.S. Environmental Protection Agency, RTP, USA
| | - Marta Barenys
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Ellen Fritsche
- IUF-Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
| | - Magdalini Sachana
- European Commission Joint Research Centre, Institute for Health and Consumer Protection, Ispra, Italy
| | - M E Bette Meek
- McLaughlin Centre for Risk Science, University of Ottawa, Ottawa, Canada
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Carcinogenicity and mode of action evaluation for alpha-hexachlorocyclohexane: Implications for human health risk assessment. Regul Toxicol Pharmacol 2016; 76:152-73. [DOI: 10.1016/j.yrtph.2015.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 01/30/2023]
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7
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Chepelev NL, Moffat ID, Labib S, Bourdon-Lacombe J, Kuo B, Buick JK, Lemieux F, Malik AI, Halappanavar S, Williams A, Yauk CL. Integrating toxicogenomics into human health risk assessment: lessons learned from the benzo[a]pyrene case study. Crit Rev Toxicol 2015; 45:44-52. [PMID: 25605027 DOI: 10.3109/10408444.2014.973935] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The use of short-term toxicogenomic tests to predict cancer (or other health effects) offers considerable advantages relative to traditional toxicity testing methods. The advantages include increased throughput, increased mechanistic data, and significantly reduced costs. However, precisely how toxicogenomics data can be used to support human health risk assessment (RA) is unclear. In a companion paper ( Moffat et al. 2014 ), we present a case study evaluating the utility of toxicogenomics in the RA of benzo[a]pyrene (BaP), a known human carcinogen. The case study is meant as a proof-of-principle exercise using a well-established mode of action (MOA) that impacts multiple tissues, which should provide a best case example. We found that toxicogenomics provided rich mechanistic data applicable to hazard identification, dose-response analysis, and quantitative RA of BaP. Based on this work, here we share some useful lessons for both research and RA, and outline our perspective on how toxicogenomics can benefit RA in the short- and long-term. Specifically, we focus on (1) obtaining biologically relevant data that are readily suitable for establishing an MOA for toxicants, (2) examining the human relevance of an MOA from animal testing, and (3) proposing appropriate quantitative values for RA. We describe our envisioned strategy on how toxicogenomics can become a tool in RA, especially when anchored to other short-term toxicity tests (apical endpoints) to increase confidence in the proposed MOA, and emphasize the need for additional studies on other MOAs to define the best practices in the application of toxicogenomics in RA.
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Affiliation(s)
- Nikolai L Chepelev
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, ON , Canada
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8
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Becker RA, Patlewicz G, Simon TW, Rowlands JC, Budinsky RA. The adverse outcome pathway for rodent liver tumor promotion by sustained activation of the aryl hydrocarbon receptor. Regul Toxicol Pharmacol 2015; 73:172-90. [PMID: 26145830 DOI: 10.1016/j.yrtph.2015.06.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 06/19/2015] [Accepted: 06/22/2015] [Indexed: 12/29/2022]
Abstract
An Adverse Outcome Pathway (AOP) represents the existing knowledge of a biological pathway leading from initial molecular interactions of a toxicant and progressing through a series of key events (KEs), culminating with an apical adverse outcome (AO) that has to be of regulatory relevance. An AOP based on the mode of action (MOA) of rodent liver tumor promotion by dioxin-like compounds (DLCs) has been developed and the weight of evidence (WoE) of key event relationships (KERs) evaluated using evolved Bradford Hill considerations. Dioxins and DLCs are potent aryl hydrocarbon receptor (AHR) ligands that cause a range of species-specific adverse outcomes. The occurrence of KEs is necessary for inducing downstream biological responses and KEs may occur at the molecular, cellular, tissue and organ levels. The common convention is that an AOP begins with the toxicant interaction with a biological response element; for this AOP, this initial event is binding of a DLC ligand to the AHR. Data from mechanistic studies, lifetime bioassays and approximately thirty initiation-promotion studies have established dioxin and DLCs as rat liver tumor promoters. Such studies clearly show that sustained AHR activation, weeks or months in duration, is necessary to induce rodent liver tumor promotion--hence, sustained AHR activation is deemed the molecular initiating event (MIE). After this MIE, subsequent KEs are 1) changes in cellular growth homeostasis likely associated with expression changes in a number of genes and observed as development of hepatic foci and decreases in apoptosis within foci; 2) extensive liver toxicity observed as the constellation of effects called toxic hepatopathy; 3) cellular proliferation and hyperplasia in several hepatic cell types. This progression of KEs culminates in the AO, the development of hepatocellular adenomas and carcinomas and cholangiolar carcinomas. A rich data set provides both qualitative and quantitative knowledge of the progression of this AOP through KEs and the KERs. Thus, the WoE for this AOP is judged to be strong. Species-specific effects of dioxins and DLCs are well known--humans are less responsive than rodents and rodent species differ in sensitivity between strains. Consequently, application of this AOP to evaluate potential human health risks must take these differences into account.
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Affiliation(s)
- Richard A Becker
- Regulatory and Technical Affairs Department, American Chemistry Council (ACC), Washington, DC 20002, USA.
| | - Grace Patlewicz
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Ted W Simon
- Ted Simon LLC, 4184 Johnston Road, Winston, GA 30187, USA
| | - J Craig Rowlands
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
| | - Robert A Budinsky
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
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9
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Meek M(B, Lipscomb JC. Gaining acceptance for the use of in vitro toxicity assays and QIVIVE in regulatory risk assessment. Toxicology 2015; 332:112-23. [DOI: 10.1016/j.tox.2015.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 12/31/2014] [Accepted: 01/14/2015] [Indexed: 12/01/2022]
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10
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Mode of action and human relevance of pronamide-induced rat thyroid tumors. Regul Toxicol Pharmacol 2015; 71:541-51. [DOI: 10.1016/j.yrtph.2015.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 02/14/2015] [Accepted: 02/16/2015] [Indexed: 11/20/2022]
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11
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Chepelev NL, Moffat ID, Bowers WJ, Yauk CL. Neurotoxicity may be an overlooked consequence of benzo[a]pyrene exposure that is relevant to human health risk assessment. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2015; 764:64-89. [DOI: 10.1016/j.mrrev.2015.03.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 02/05/2023]
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12
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Patlewicz G, Simon TW, Rowlands JC, Budinsky RA, Becker RA. Proposing a scientific confidence framework to help support the application of adverse outcome pathways for regulatory purposes. Regul Toxicol Pharmacol 2015; 71:463-77. [PMID: 25707856 DOI: 10.1016/j.yrtph.2015.02.011] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 10/24/2022]
Abstract
An adverse outcome pathway (AOP) describes the causal linkage between initial molecular events and an adverse outcome at individual or population levels. Whilst there has been considerable momentum in AOP development, far less attention has been paid to how AOPs might be practically applied for different regulatory purposes. This paper proposes a scientific confidence framework (SCF) for evaluating and applying a given AOP for different regulatory purposes ranging from prioritizing chemicals for further evaluation, to hazard prediction, and ultimately, risk assessment. The framework is illustrated using three different AOPs for several typical regulatory applications. The AOPs chosen are ones that have been recently developed and/or published, namely those for estrogenic effects, skin sensitisation, and rodent liver tumor promotion. The examples confirm how critical the data-richness of an AOP is for driving its practical application. In terms of performing risk assessment, human dosimetry methods are necessary to inform meaningful comparisons with human exposures; dosimetry is applied to effect levels based on non-testing approaches and in vitro data. Such a comparison is presented in the form of an exposure:activity ratio (EAR) to interpret biological activity in the context of exposure and to provide a basis for product stewardship and regulatory decision making.
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Affiliation(s)
- Grace Patlewicz
- DuPont Haskell Global Centers for Health and Environmental Sciences, 1090 Elkton Road, Newark, DE 19711, USA.
| | - Ted W Simon
- Ted Simon LLC, 4184 Johnston Road, Winston, GA 30187, USA
| | - J Craig Rowlands
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
| | - Robert A Budinsky
- The Dow Chemical Company, Toxicology & Environmental Research & Consulting, 1803 Building Washington Street, Midland, MI 48674, USA
| | - Richard A Becker
- Regulatory and Technical Affairs Department, American Chemistry Council (ACC), Washington, DC 20002, USA
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13
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Dingley KH, Ubick EA, Vogel JS, Ognibene TJ, Malfatti MA, Kulp K, Haack KW. DNA isolation and sample preparation for quantification of adduct levels by accelerator mass spectrometry. Methods Mol Biol 2014; 1105:147-57. [PMID: 24623226 DOI: 10.1007/978-1-62703-739-6_12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Accelerator mass spectrometry (AMS) is a highly sensitive technique used for the quantification of adducts following exposure to carbon-14- or tritium-labeled chemicals, with detection limits in the range of one adduct per 10(11)-10(12) nucleotides. The protocol described in this chapter provides an optimal method for isolating and preparing DNA samples to measure isotope-labeled DNA adducts by AMS. When preparing samples, special precautions must be taken to avoid cross-contamination of isotope among samples and produce a sample that is compatible with AMS. The DNA isolation method described is based upon digestion of tissue with proteinase K, followed by extraction of DNA using Qiagen isolation columns. The extracted DNA is precipitated with isopropanol, washed repeatedly with 70 % ethanol to remove salt, and then dissolved in water. DNA samples are then converted to graphite or titanium hydride and the isotope content measured by AMS to quantify adduct levels. This method has been used to reliably generate good yields of uncontaminated, pure DNA from animal and human tissues for analysis of adduct levels.
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Affiliation(s)
- Karen H Dingley
- Biology and Biotechnology Research Program, Center for Accelerator Mass Spectroscopy, Lawrence Livermore National Laboratory, Livermore, CA, 94551, USA,
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Chepelev NL, Meek MEB, Yauk CL. Application of benchmark dose modeling to protein expression data in the development and analysis of mode of action/adverse outcome pathways for testicular toxicity. J Appl Toxicol 2014; 34:1115-21. [DOI: 10.1002/jat.3071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/28/2014] [Accepted: 08/11/2014] [Indexed: 02/04/2023]
Affiliation(s)
- Nikolai L. Chepelev
- Environmental and Radiation Health Sciences Directorate; Health Canada; Ottawa ON K1A 0K9 Canada
| | - M. E. Bette Meek
- R. Samuel McLaughlin Centre for Population Health Risk Assessment; University of Ottawa; One Stewart Street, Suite 309 Ottawa ON K1N 6N5 Canada
| | - Carole Lyn Yauk
- Environmental and Radiation Health Sciences Directorate; Health Canada; Ottawa ON K1A 0K9 Canada
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Simon TW, Simons SS, Preston RJ, Boobis AR, Cohen SM, Doerrer NG, Fenner-Crisp PA, McMullin TS, McQueen CA, Rowlands JC. The use of mode of action information in risk assessment: Quantitative key events/dose-response framework for modeling the dose-response for key events. Crit Rev Toxicol 2014; 44 Suppl 3:17-43. [DOI: 10.3109/10408444.2014.931925] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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16
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Meek MEB, Palermo CM, Bachman AN, North CM, Jeffrey Lewis R. Mode of action human relevance (species concordance) framework: Evolution of the Bradford Hill considerations and comparative analysis of weight of evidence. J Appl Toxicol 2014; 34:595-606. [PMID: 24777878 PMCID: PMC4321063 DOI: 10.1002/jat.2984] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 11/28/2013] [Accepted: 12/03/2013] [Indexed: 12/30/2022]
Abstract
The mode of action human relevance (MOA/HR) framework increases transparency in systematically considering data on MOA for end (adverse) effects and their relevance to humans. This framework continues to evolve as experience increases in its application. Though the MOA/HR framework is not designed to address the question of "how much information is enough" to support a hypothesized MOA in animals or its relevance to humans, its organizing construct has potential value in considering relative weight of evidence (WOE) among different cases and hypothesized MOA(s). This context is explored based on MOA analyses in published assessments to illustrate the relative extent of supporting data and their implications for dose-response analysis and involved comparisons for chemical assessments on trichloropropane, and carbon tetrachloride with several hypothesized MOA(s) for cancer. The WOE for each hypothesized MOA was summarized in narrative tables based on comparison and contrast of the extent and nature of the supporting database versus potentially inconsistent or missing information. The comparison was based on evolved Bradford Hill considerations rank ordered to reflect their relative contribution to WOE determinations of MOA taking into account increasing experience in their application internationally. This clarification of considerations for WOE determinations as a basis for comparative analysis is anticipated to contribute to increasing consistency in the application of MOA/HR analysis and potentially, transparency in separating science judgment from public policy considerations in regulatory risk assessment.
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Affiliation(s)
- M E Bette Meek
- University of Ottawa, One Stewart Street, Suite 309, Ottawa, Ontario, K1N 6N5, Canada
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Budinsky RA, Schrenk D, Simon T, Van den Berg M, Reichard JF, Silkworth JB, Aylward LL, Brix A, Gasiewicz T, Kaminski N, Perdew G, Starr TB, Walker NJ, Rowlands JC. Mode of action and dose–response framework analysis for receptor-mediated toxicity: The aryl hydrocarbon receptor as a case study. Crit Rev Toxicol 2013; 44:83-119. [DOI: 10.3109/10408444.2013.835787] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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18
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Corton JC, Cunningham ML, Hummer BT, Lau C, Meek B, Peters JM, Popp JA, Rhomberg L, Seed J, Klaunig JE. Mode of action framework analysis for receptor-mediated toxicity: The peroxisome proliferator-activated receptor alpha (PPARα) as a case study. Crit Rev Toxicol 2013; 44:1-49. [PMID: 24180432 DOI: 10.3109/10408444.2013.835784] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Several therapeutic agents and industrial chemicals induce liver tumors in rodents through the activation of the peroxisome proliferator-activated receptor alpha (PPARα). The cellular and molecular events by which PPARα activators induce rodent hepatocarcinogenesis has been extensively studied and elucidated. This review summarizes the weight of evidence relevant to the hypothesized mode of action (MOA) for PPARα activator-induced rodent hepatocarcinogenesis and identifies gaps in our knowledge of this MOA. Chemical-specific and mechanistic data support concordance of temporal and dose-response relationships for the key events associated with many PPARα activators including a phthalate ester plasticizer di(2-ethylhexyl) phthalate (DEHP) and the drug gemfibrozil. While biologically plausible in humans, the hypothesized key events in the rodent MOA, for PPARα activators, are unlikely to induce liver tumors in humans because of toxicodynamic and biological differences in responses. This conclusion is based on minimal or no effects observed on growth pathways, hepatocellular proliferation and liver tumors in humans and/or species (including hamsters, guinea pigs and cynomolgous monkeys) that are more appropriate human surrogates than mice and rats at overlapping dose levels. Overall, the panel concluded that significant quantitative differences in PPARα activator-induced effects related to liver cancer formation exist between rodents and humans. On the basis of these quantitative differences, most of the workgroup felt that the rodent MOA is "not relevant to humans" with the remaining members concluding that the MOA is "unlikely to be relevant to humans". The two groups differed in their level of confidence based on perceived limitations of the quantitative and mechanistic knowledge of the species differences, which for some panel members strongly supports but cannot preclude the absence of effects under unlikely exposure scenarios.
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Meek ME, Boobis A, Cote I, Dellarco V, Fotakis G, Munn S, Seed J, Vickers C. New developments in the evolution and application of the WHO/IPCS framework on mode of action/species concordance analysis. J Appl Toxicol 2013; 34:1-18. [PMID: 24166207 PMCID: PMC6701984 DOI: 10.1002/jat.2949] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 09/19/2013] [Indexed: 01/25/2023]
Abstract
The World Health Organization/International Programme on Chemical Safety mode of action/human relevance framework has been updated to reflect the experience acquired in its application and extend its utility to emerging areas in toxicity testing and non-testing methods. The underlying principles have not changed, but the framework’s scope has been extended to enable integration of information at different levels of biological organization and reflect evolving experience in a much broader range of potential applications. Mode of action/species concordance analysis can also inform hypothesis-based data generation and research priorities in support of risk assessment. The modified framework is incorporated within a roadmap, with feedback loops encouraging continuous refinement of fit-for-purpose testing strategies and risk assessment. Important in this construct is consideration of dose–response relationships and species concordance analysis in weight of evidence. The modified Bradford Hill considerations have been updated and additionally articulated to reflect increasing experience in application for cases where the toxicological outcome of chemical exposure is known. The modified framework can be used as originally intended, where the toxicological effects of chemical exposure are known, or in hypothesizing effects resulting from chemical exposure, using information on putative key events in established modes of action from appropriate in vitro or in silico systems and other lines of evidence. This modified mode of action framework and accompanying roadmap and case examples are expected to contribute to improving transparency in explicitly addressing weight of evidence considerations in mode of action/species concordance analysis based on both conventional data sources and evolving methods.
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Affiliation(s)
- M E Meek
- Chemical Risk Assessment, McLaughlin Centre for Population Health Risk Assessment, 1 Stewart Street, Ottawa, Ontario, Canada, K1N 6N5
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Dourson M, Becker RA, Haber LT, Pottenger LH, Bredfeldt T, Fenner-Crisp PA. Advancing human health risk assessment: integrating recent advisory committee recommendations. Crit Rev Toxicol 2013; 43:467-92. [PMID: 23844697 PMCID: PMC3725687 DOI: 10.3109/10408444.2013.807223] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 11/13/2022]
Abstract
Over the last dozen years, many national and international expert groups have considered specific improvements to risk assessment. Many of their stated recommendations are mutually supportive, but others appear conflicting, at least in an initial assessment. This review identifies areas of consensus and difference and recommends a practical, biology-centric course forward, which includes: (1) incorporating a clear problem formulation at the outset of the assessment with a level of complexity that is appropriate for informing the relevant risk management decision; (2) using toxicokinetics and toxicodynamic information to develop Chemical Specific Adjustment Factors (CSAF); (3) using mode of action (MOA) information and an understanding of the relevant biology as the key, central organizing principle for the risk assessment; (4) integrating MOA information into dose-response assessments using existing guidelines for non-cancer and cancer assessments; (5) using a tiered, iterative approach developed by the World Health Organization/International Programme on Chemical Safety (WHO/IPCS) as a scientifically robust, fit-for-purpose approach for risk assessment of combined exposures (chemical mixtures); and (6) applying all of this knowledge to enable interpretation of human biomonitoring data in a risk context. While scientifically based defaults will remain important and useful when data on CSAF or MOA to refine an assessment are absent or insufficient, assessments should always strive to use these data. The use of available 21st century knowledge of biological processes, clinical findings, chemical interactions, and dose-response at the molecular, cellular, organ and organism levels will minimize the need for extrapolation and reliance on default approaches.
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Affiliation(s)
- Michael Dourson
- Toxicology Excellence for Risk Assessment, Cincinnati, OH, USA.
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Case study illustrating the WHO IPCS guidance on characterization and application of physiologically based pharmacokinetic models in risk assessment. Regul Toxicol Pharmacol 2013; 66:116-29. [PMID: 23535119 DOI: 10.1016/j.yrtph.2013.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 02/28/2013] [Accepted: 03/02/2013] [Indexed: 11/20/2022]
Abstract
The World Health Organization (WHO) International Programme on Chemical Safety (IPCS) Guidance on Characterization and Application of Physiologically Based Pharmacokinetic Models in Risk Assessment (IPCS, 2010) describes key principles for risk assessors and model developers. In the WHO Guidance, a template for model documentation was developed and a case study included. Here the WHO Guidance, including the template, is summarized and an additional case study is presented to illustrate its application, based upon an existing risk assessment for 2-butoxyethanol (CAS NO. 111-76-2). The goal of the WHO Guidance and the current paper is to increase regulatory acceptance of complex biologically descriptive pharmacokinetic (or toxicokinetic) models, such as PBPK models, by facilitating communication and successful interaction between modelers and risk assessors.
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Piccirillo VJ, Bird MG, Lewis RJ, Bover WJ. Preliminary evaluation of the human relevance of respiratory tumors observed in rodents exposed to naphthalene. Regul Toxicol Pharmacol 2012; 62:433-40. [PMID: 22342949 DOI: 10.1016/j.yrtph.2012.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/24/2012] [Accepted: 01/28/2012] [Indexed: 11/17/2022]
Abstract
Inhalation bioassays in mice and rats exposed to naphthalene (NA) show incidences of lung and nasal cancer, respectively. This paper describes a preliminary mode of action (MOA)/human relevance (HR) framework for NA. Species differences in both carcinogenic and cytotoxic responses between the rodent and human have been noted based on qualitative and quantitative differences in metabolism. Some occur at the initial oxidation of NA in the rat through CYP2F, versus CYP2A13 metabolism in the human respiratory system and which results in a difference in the specific naphthoquinone formed. Normally, subsequent reactive metabolites are then conjugated through glutathione, but high dose exposures, as in the rat bioassay, result in glutathione depletion, and the availability of 1,2-naphthoquinone for other conjugation. In the rat nose, it is proposed that a naphthoquinone imine is formed via a species and site-specific aryl amidase acting on an amino acid conjugate of the quinone. Such a quinone imine is believed to be the active agent in Alachlor and phenacetin, resulting in the same profile of respiratory tumors in the rat as NA. Based on the MOA and the limited epidemiological data indicating no human evidence of nasal or lung tumor risk, the carcinogenic response observed in rats does not appear relevant to the human.
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Klaunig JE, Hocevar BA, Kamendulis LM. Mode of Action analysis of perfluorooctanoic acid (PFOA) tumorigenicity and Human Relevance. Reprod Toxicol 2011; 33:410-418. [PMID: 22120428 DOI: 10.1016/j.reprotox.2011.10.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 10/01/2011] [Accepted: 10/24/2011] [Indexed: 11/19/2022]
Abstract
Perfluorooctanoic acid (PFOA) is an environmentally persistent chemical used in the manufacturing of a wide array of industrial and commercial products. PFOA has been shown to induce tumors of the liver, testis and pancreas (tumor triad) in rats following chronic dietary administration. PFOA belongs to a group of compounds that are known to activate the PPARα receptor. The PPARα activation Mode of Action was initially addressed in 2003 [9] and further refined in subsequent reviews [92-94]. In the intervening time, additional information on PFOA effects as well as a further refinement of the Mode of Action framework warrants a re-examination of this compound for its cancer induction Mode of Action. This review will address the rodent (rat) cancer data and cancer Mode of Action of PFOA for tumors of the liver, testes and pancreas.
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Affiliation(s)
- James E Klaunig
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States.
| | - Barbara A Hocevar
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States
| | - Lisa M Kamendulis
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States
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Strategies in case of positive in vivo results in genotoxicity testing. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 723:121-8. [DOI: 10.1016/j.mrgentox.2010.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/08/2010] [Indexed: 01/23/2023]
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25
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Dearfield KL, Thybaud V, Cimino MC, Custer L, Czich A, Harvey JS, Hester S, Kim JH, Kirkland D, Levy DD, Lorge E, Moore MM, Ouédraogo-Arras G, Schuler M, Suter W, Sweder K, Tarlo K, van Benthem J, van Goethem F, Witt KL. Follow-up actions from positive results of in vitro genetic toxicity testing. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:177-204. [PMID: 20963811 DOI: 10.1002/em.20617] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/16/2010] [Accepted: 06/18/2010] [Indexed: 05/30/2023]
Abstract
Appropriate follow-up actions and decisions are needed when evaluating and interpreting clear positive results obtained in the in vitro assays used in the initial genotoxicity screening battery (i.e., the battery of tests generally required by regulatory authorities) to assist in overall risk-based decision making concerning the potential effects of human exposure to the agent under test. Over the past few years, the International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing developed a decision process flow chart to be applied in case of clear positive results in vitro. It provides for a variety of different possibilities and allows flexibility in choosing follow-up action(s), depending on the results obtained in the initial battery of assays and available information. The intent of the Review Subgroup was not to provide a prescriptive testing strategy, but rather to reinforce the concept of weighing the totality of the evidence. The Review Subgroup of the IVGT committee highlighted the importance of properly analyzing the existing data, and considering potential confounding factors (e.g., possible interactions with the test systems, presence of impurities, irrelevant metabolism), and chemical modes of action when analyzing and interpreting positive results in the in vitro genotoxicity assays and determining appropriate follow-up testing. The Review Subgroup also examined the characteristics, strengths, and limitations of each of the existing in vitro and in vivo genotoxicity assays to determine their usefulness in any follow-up testing.
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Affiliation(s)
- Kerry L Dearfield
- U.S. Department of Agriculture, Food Safety and Inspection Service, Washington, District of Columbia, USA
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Perkins EJ, Chipman JK, Edwards S, Habib T, Falciani F, Taylor R, Van Aggelen G, Vulpe C, Antczak P, Loguinov A. Reverse engineering adverse outcome pathways. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:22-38. [PMID: 20963852 DOI: 10.1002/etc.374] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The toxicological effects of many stressors are mediated through unknown, or incompletely characterized, mechanisms of action. The application of reverse engineering complex interaction networks from high dimensional omics data (gene, protein, metabolic, signaling) can be used to overcome these limitations. This approach was used to characterize adverse outcome pathways (AOPs) for chemicals that disrupt the hypothalamus-pituitary-gonadal endocrine axis in fathead minnows (FHM, Pimephales promelas). Gene expression changes in FHM ovaries in response to seven different chemicals, over different times, doses, and in vivo versus in vitro conditions, were captured in a large data set of 868 arrays. Potential AOPs of the antiandrogen flutamide were examined using two mutual information-based methods to infer gene regulatory networks and potential AOPs. Representative networks from these studies were used to predict network paths from stressor to adverse outcome as candidate AOPs. The relationship of individual chemicals to an adverse outcome can be determined by following perturbations through the network in response to chemical treatment, thus leading to the nodes associated with the adverse outcome. Identification of candidate pathways allows for formation of testable hypotheses about key biological processes, biomarkers, or alternative endpoints that can be used to monitor an AOP. Finally, the unique challenges facing the application of this approach in ecotoxicology were identified and a road map for the utilization of these tools presented.
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Affiliation(s)
- Edward J Perkins
- U.S. Army Engineering Research and Development Center, Vicksburg, Mississippi, USA.
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27
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Bonvallot N, Mandin C, Mercier F, Le Bot B, Glorennec P. Health ranking of ingested semi-volatile organic compounds in house dust: an application to France. INDOOR AIR 2010; 20:458-472. [PMID: 20636335 DOI: 10.1111/j.1600-0668.2010.00667.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
UNLABELLED People spend most of their time indoors. Dust settled in the home may be contaminated by semi-volatile organic compounds (SVOCs). Exposure to these compounds is of great concern, in particular for infants. Their number is large so arose the question of which ones should be selected for dust ingestion exposure assessment. This work proposes a health ranking of SVOCs ingested through settled dust. This ranking is based on the toxicity and contamination of SVOCs in dust. Data on compounds and contamination was retrieved from a bibliographic review. Where possible, toxicity data was retrieved from databases, otherwise it was calculated from raw data. One hundred and fifty-six SVOCs were selected, 66 of which were prioritized. Forty-two could not be prioritized because contamination data was below the limit of detection, and 48 could not be prioritized because there was no contamination or toxicity data. The top-ranked compounds were phthalates, pesticides, short-chain chlorinated paraffins, PBDEs, PFCs, organotins, PCBs, and PAHs. As most of these have reprotoxic and neurotoxic properties, an integrated multi-pollutants approach to exposure is required and simultaneous measurement methods should be developed. PRACTICAL IMPLICATIONS The large number of compounds identified in settled dust in recent years should be considered for the assessment of exposure to dust ingestion. This work provides a health ranking of SVOCs ingested through settled dust. Most of the top-ranked compounds have reprotoxic and neurotoxic properties, and particular attention should, therefore, be paid to them in future studies.
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Affiliation(s)
- N Bonvallot
- EHESP School of Public Health, Rennes, France
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29
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Derived Reference Doses (RfDs) for the environmental degradates of the herbicides alachlor and acetochlor: Results of an independent expert panel deliberation. Regul Toxicol Pharmacol 2010; 57:220-34. [DOI: 10.1016/j.yrtph.2010.02.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 02/26/2010] [Accepted: 02/28/2010] [Indexed: 11/23/2022]
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Andersen ME, Krewski D. The Vision of Toxicity Testing in the 21st Century: Moving from Discussion to Action. Toxicol Sci 2010; 117:17-24. [DOI: 10.1093/toxsci/kfq188] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Meek MEB, Klaunig JE. Proposed mode of action of benzene-induced leukemia: Interpreting available data and identifying critical data gaps for risk assessment. Chem Biol Interact 2010; 184:279-85. [PMID: 20153303 DOI: 10.1016/j.cbi.2010.02.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Mode of action is defined as a series of key biological events leading to an observed toxicological effect (for example, metabolism to a toxic entity, cell death, regenerative repair and tumors). It contrasts with mechanism of action, which generally involves a detailed understanding of the molecular basis for an effect. A framework to consider the weight of evidence for hypothesized modes of action in animals and their relevance to humans, has been widely adopted and used by government agencies and international organizations. The framework, developed and refined through its application in case studies for principally non-DNA-reactive carcinogens, has more recently been extended to DNA-reactive carcinogens, non-cancer endpoints and different life stages. In addition to increasing transparency, use of the framework promotes consistency in decision-making concerning adequacy of weight of evidence, facilitates peer input and review and identifies critical research needs. The framework provides an effective tool to facilitate discussion between the research and risk assessment communities on critical data gaps, which if filled, would permit more refined estimates of risk. As a basis for additionally coordinating and focusing research on critical data gaps in a risk assessment context, five key events in the mode of action for benzene-induced leukemia are proposed: (1) benzene metabolism via Cytochrome P450, (2) the interaction of benzene metabolites with target cells in the bone marrow, (3) formation of initiated, mutated target cells, (4) selective proliferation of the mutated cells and (5) production of leukemia. These key events are considered in a framework analysis of human relevance as a basis to consider appropriate next steps in developing research strategies.
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Affiliation(s)
- M E Bette Meek
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, One Stewart Street, Suite 309, Ottawa, Ontario, Canada.
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Rhomberg LR. Toxicity testing in the 21st century: how will it affect risk assessment? JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2010; 13:361-375. [PMID: 20574908 DOI: 10.1080/10937404.2010.483951] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
New-technology testing such as gene-expression arrays and high-throughput cell-based assays provides a new window on assessing the impact of chemical exposures that directly examines effects at the level of the underlying biochemical machinery that controls and modulates the living system. Because such assays enable the testing of many chemicals in different conditions at low cost, these assays promise to help address the difficulty that traditional animal testing has in keeping up with increasing regulatory demands for fuller and more comprehensive chemical characterization. Examining a large array of gene-expression changes simultaneously provides multivariate data that are useful for data mining and statistical analysis of predictive profiles, even if the mechanistic role of each change is not well understood. In the future, however, the mechanistic interpretation of such data as embodiment of biological control processes, their perturbation, and their possible failure will become critical as primary observations, from which potential apical toxicity can be deduced without resorting to in vivo animal testing. The vision of such application put forth in the 2007 National Academy of Sciences report, Toxicity Testing in the 21st Century is discussed with what realization of that vision will mean for revision of risk assessment approaches, which are tied to the information available from testing considered. Even short of attainment of this vision, however, the new-technology data have useful applications as screening tools, as biomarkers, as diagnoses and characterizations of mode of action, in dose-response analysis, and as a means for characterizing interindividual variability. Possibilities, pitfalls, and impacts on risk assessment methods are described.
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Meek ME, Levy LS, Beck BD, Danzeisen R, Donohue JM, Arnold IMF, Krewski D. Risk assessment practice for essential metals. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:253-260. [PMID: 20077295 DOI: 10.1080/15287390903340922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This article addresses the content of the workshop, including a panel discussion relevant to delineation of a path forward in relation to risk assessment of essential metals. The state of the art of risk assessment and associated issues for essential metals are outlined initially, followed by brief illustration by the case studies considered at the workshop (i.e., copper, zinc, and manganese). Approaches for the future testing strategies of essential metals are discussed in terms of options to increase efficiency and accuracy of assessments. Subsequently, recommendations for pragmatic next steps to advance progress and facilitate uptake by the regulatory risk assessment community are presented.
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Affiliation(s)
- M E Meek
- McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, Ottawa, Ontario K1N 6N5,, Canada.
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Cruzan G, Bus J, Banton M, Gingell R, Carlson G. Mouse specific lung tumors from CYP2F2-mediated cytotoxic metabolism: An endpoint/toxic response where data from multiple chemicals converge to support a mode of action. Regul Toxicol Pharmacol 2009; 55:205-18. [DOI: 10.1016/j.yrtph.2009.07.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 11/28/2022]
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Vonk JA, Benigni R, Hewitt M, Nendza M, Segner H, van de Meent D, Cronin MT. The use of Mechanisms and Modes of Toxic Action in Integrated Testing Strategies: The Report and Recommendations of a Workshop held as part of the European Union OSIRIS Integrated Project. Altern Lab Anim 2009; 37:557-71. [DOI: 10.1177/026119290903700512] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This report on The Potential of Mode of Action (MoA) Information Derived from Non-testing and Screening Methodologies to Support Informed Hazard Assessment, resulted from a workshop organised within OSIRIS (Optimised Strategies for Risk Assessment of Industrial Chemicals through Integration of Non-test and Test Information), a project partly funded by the EU Commission within the Sixth Framework Programme. The workshop was held in Liverpool, UK, on 30 October 2008, with 35 attendees. The goal of the OSIRIS project is to develop integrated testing strategies (ITS) fit for use in the REACH system, that would enable a significant increase in the use of non-testing information for regulatory decision making, and thus minimise the need for animal testing. One way to improve the evaluation of chemicals may be through categorisation by way of mechanisms or modes of toxic action. Defining such groups can enhance read-across possibilities and priority settings for certain toxic modes or chemical structures responsible for these toxic modes. Overall, this may result in a reduction of in vivo testing on organisms, through combining available data on mode of action and a focus on the potentially most-toxic groups. In this report, the possibilities of a mechanistic approach to assist in and guide ITS are explored, and the differences between human health and environmental areas are summarised.
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Affiliation(s)
- J. Arie Vonk
- Laboratory for Ecological Risk Assessment, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Romualdo Benigni
- Laboratory of Comparative Toxicology, Environment and Health Department, Istituto Superiore di Sanita, Rome, Italy
| | - Mark Hewitt
- School of Pharmacy and Chemistry, Liverpool John Moores University, Liverpool, UK
| | | | - Helmut Segner
- Centre for Fish and Wildlife Health, Vetsuisse Faculty, University of Berne, Berne, Switzerland
| | - Dik van de Meent
- Laboratory for Ecological Risk Assessment, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Mark T.D. Cronin
- School of Pharmacy and Chemistry, Liverpool John Moores University, Liverpool, UK
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Letter to the Editor in Response to Forristal et al.: Improving the Quality of Risk Assessments in Canada Using a Principle-Based Approach, Regulatory Toxicology and Pharmacology 50 (2008) 336–344. Regul Toxicol Pharmacol 2009; 53:156-7; author reply 158. [DOI: 10.1016/j.yrtph.2008.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Accepted: 12/03/2008] [Indexed: 11/21/2022]
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Meek B, Doull J. Pragmatic challenges for the vision of toxicity testing in the 21st century in a regulatory context: another Ames test?.or a new edition of "the Red Book"? Toxicol Sci 2009; 108:19-21. [PMID: 19168570 PMCID: PMC2644399 DOI: 10.1093/toxsci/kfp008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Bette Meek
- McLaughlin Institute for Population Health Risk Assessment, University of Ottawa, Tunney's Pasture, Address Locator 0801C2, Ottawa K1A 0L2, Ontario, Canada
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38
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Edwards SW, Preston RJ. Systems Biology and Mode of Action Based Risk Assessment. Toxicol Sci 2008; 106:312-8. [DOI: 10.1093/toxsci/kfn190] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Nishikawa A, Umemura T, Ishii Y, Tasaki M, Okamura T, Inoue T, Masumura K, Nohmi T. In vivo Approaches to Study Mechanism of Action of Genotoxic Carcinogens. Genes Environ 2008. [DOI: 10.3123/jemsge.30.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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