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Chen S, Shi Z, Zhang Q. A physiologically based pharmacokinetic model of diethyl phthalates in humans. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 340:122849. [PMID: 37926418 PMCID: PMC10841618 DOI: 10.1016/j.envpol.2023.122849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
Phthalates are a family of industrial and consumer product chemicals, among which diethyl phthalate (DEP) has been widely used. DEP is metabolized into the active metabolite monoethyl phthalate (MEP) and exposure to DEP may induce male reproductive toxicity, developmental toxicity and hepatotoxicity. To better assess the toxicity of DEP and MEP, it is important to understand and predict their internal concentrations, especially in reproductive organs. Here we present a human physiologically based pharmacokinetic (PBPK) model of DEP. Implemented in R, the PBPK model consists of seven tissue compartments, including blood, gut, liver, fat, skin, gonad, and rest of body (RB). In the blood both DEP and MEP partition into free and bound forms, and tissue distribution is considered as blood flow-limited. DEP is metabolized in the gut and liver into MEP which is further glucuronidated and cleared through the urine. The chemical-specific parameters of the model were predicted in silico or estimated based on published human urinary MEP data after exposure to DEP in the air at 250 or 300 μg/m3 for 3 or 6 h through inhalation and dermal absorption. Sensitivity analysis identified important parameters including partition coefficients of DEP for fat, RB, and skin compartments, and the rate constants for glucuronidation of MEP and urinary excretion, with regard to Cmax, area under the curve (AUC), and clearance half-lives of DEP and MEP. A subset of the sensitive parameters was then included in hierarchical population Bayesian Markov chain Monte Carlo (MCMC) simulations to characterize the uncertainty and variability of these parameters. The model is consistent with the notion that dermal absorption represents a significant route of exposure to DEP in ambient air and clothing can be an effective barrier. The developed human PBPK model can be utilized upon further refinement as a quantitative tool for DEP risk assessment.
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Affiliation(s)
- Shiyu Chen
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, GA 30322, USA
| | - Zhenzhen Shi
- The Program for Experimental and Theoretical Modeling, Division of Hepatology, Department of Medicine, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, 60660, USA
| | - Qiang Zhang
- Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, GA 30322, USA.
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2
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El Fouikar S, Duranthon V, Helies V, Jammes H, Couturier-Tarrade A, Gayrard V, Van Acker N, Frenois FX, Archilla C, Rousseau-Ralliard D, Gatimel N, Léandri R. Multigenerational Effects of a Complex Human-Relevant Exposure during Folliculogenesis and Preimplantation Embryo Development: The FEDEXPO Study. TOXICS 2023; 11:toxics11050425. [PMID: 37235240 DOI: 10.3390/toxics11050425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023]
Abstract
Animal toxicological studies often fail to mimic the complexity of the human exposome, associating low doses, combined molecules and long-term exposure. Since the reproductive potential of a woman begins in the fetal ovary, the literature regarding the disruption of its reproductive health by environmental toxicants remains limited. Studies draw attention to follicle development, a major determinant for the quality of the oocyte, and the preimplantation embryo, as both of them are targets for epigenetic reprogramming. The "Folliculogenesis and Embryo Development EXPOsure to a mixture of toxicants: evaluation in the rabbit model" (FEDEXPO) project emerged from consideration of these limitations and aims to evaluate in the rabbit model the impacts of an exposure to a mixture of known and suspected endocrine disrupting chemicals (EDCs) during two specific windows, including folliculogenesis and preimplantation embryo development. The mixture combines eight environmental toxicants, namely perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), 2,2'4,4'-tetrabromodiphenyl ether (BDE-47), di(2-ethylhexyl) phthalate (DEHP) and bisphenol S (BPS), at relevant exposure levels for reproductive-aged women based on biomonitoring data. The project will be organized in order to assess the consequences of this exposure on the ovarian function of the directly exposed F0 females and monitor the development and health of the F1 offspring from the preimplantation stage. Emphasis will be made on the reproductive health of the offspring. Lastly, this multigenerational study will also tackle potential mechanisms for the inheritance of health disruption via the oocyte or the preimplantation embryo.
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Affiliation(s)
- Sara El Fouikar
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31062 Toulouse, France
| | | | - Virginie Helies
- GenPhySE (Génétique Physiologie et Système d'Elevage), Université de Toulouse, INRAE, ENVT, INPT, 31326 Castanet-Tolosan, France
| | - Hélène Jammes
- BREED INRAE, UVSQ, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | | | - Véronique Gayrard
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31062 Toulouse, France
| | - Nathalie Van Acker
- Plateforme Imag'IN, Service d'Anatomie Pathologie, Institut Universitaire du Cancer-Oncopole de Toulouse, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France
| | - François-Xavier Frenois
- Plateforme Imag'IN, Service d'Anatomie Pathologie, Institut Universitaire du Cancer-Oncopole de Toulouse, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France
| | | | | | - Nicolas Gatimel
- DEFE (Développement Embryonnaire, Fertilité et Environnement), UMR 1203 Inserm, Universités Toulouse et Montpellier, Toulouse Teaching Hospital Group, 31059 Toulouse, France
- Médecine de la Reproduction, Hôpital Paule de Viguier, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France
| | - Roger Léandri
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRAE, ENVT, INP-Purpan, UPS, 31062 Toulouse, France
- Médecine de la Reproduction, Hôpital Paule de Viguier, Centre Hospitalier Universitaire de Toulouse, 31059 Toulouse, France
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Yoon H, Kim TH, Lee BC, Lee B, Kim P, Shin BS, Choi J. Comparison of the exposure assessment of di(2-ethylhexyl) phthalate between the PBPK model-based reverse dosimetry and scenario-based analysis: A Korean general population study. CHEMOSPHERE 2022; 294:133549. [PMID: 35066077 DOI: 10.1016/j.chemosphere.2022.133549] [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: 10/12/2021] [Revised: 01/04/2022] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Di (2-ethylhexyl) phthalate (DEHP), classified as a reproductive toxicant, is a ubiquitous pollutant in foodstuffs, dust, and commercial products. In this study, to provide a useful cross-check on the accuracy of the exposure assessment, the estimated daily intake of DEHP was compared using reverse dosimetry with a physiologically-based pharmacokinetic (PBPK) model and a scenario-based probabilistic estimation model for six subpopulations in Korea. For reverse dosimetry analysis, the concentrations of urinary DEHP metabolites, namely mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl)phthalate (MEOHP), from three human biomonitoring program datasets were used. For the scenario-based model, we evaluated the various exposure sources of DEHP, including diet, air, indoor dust, soil, and personal care products (PCPs), and also determined its levels based on the literature review and measurements of indoor dust. The DEHP exposure doses using both exposure assessment approaches were similar in all cases, except for the 95th percentile exposure doses in toddlers (1-2 years) and young children (3-6 years). The PBPK-reverse dosimetry estimated daily intakes at the 95th percentile ranged between 22.53 and 29.90 μg/kg/day for toddlers and young children. These exceeded the reference dose (RfD) of 20 μg/kg bw/day of the US Environmental Protection Agency (EPA) based on the increased relative liver weight. Although, food was considered the primary source of DEHP, contributing to a total exposure of 50.8-75.1%, the effect of exposure to indoor dust should not be overlooked. The occurrence of high levels of DEHP in indoor dust collected from Korean homes suggests the use of a wide variety of consumer products containing DEHP. Furthermore, more attention should be paid to the high exposure levels of DEHP, especially in young children. Therefore, it is necessary to perform continuous monitoring of the indoor dust, consumer products, and the body burden of children.
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Affiliation(s)
- Hyojung Yoon
- Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea; School of Environmental Engineering, University of Seoul, Seoul, Republic of Korea
| | - Tae Hwan Kim
- College of Pharmacy, Catholic University of Daegu, Gyeongsan-si, Gyeongbuk, Republic of Korea
| | - Byoung-Cheun Lee
- Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea
| | - Byeongwoo Lee
- Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea
| | - Pilje Kim
- Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea
| | - Beom Soo Shin
- College of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do, Republic of Korea
| | - Jinhee Choi
- School of Environmental Engineering, University of Seoul, Seoul, Republic of Korea.
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Gayrard V, Moreau J, Picard-Hagen N, Helies V, Marchand P, Antignac JP, Toutain PL, Leandri R. Use of Mixture Dosing and Nonlinear Mixed Effect Modeling of Eight Environmental Contaminants in Rabbits to Improve Extrapolation Value of Toxicokinetic Data. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:117006. [PMID: 34786950 PMCID: PMC8597046 DOI: 10.1289/ehp8957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 06/01/2023]
Abstract
BACKGROUND Although in vivo studies of internal exposure to hazardous substances have been carried out for many years, there is room for progress to improve their informative value while adhering to the four R's: replacement, reduction, refinement, and responsibility rule. OBJECTIVES The objective of the study was to illustrate how toxicokinetic (TK) study design and data analysis can be implemented under the 4R rule to plan a chronic dosage regimen for investigating TK/toxicodynamic (TD) relationships. METHODS The intravenous (IV) and oral serum concentrations of eight hazardous environmental contaminants including 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (pp'DDE), ß-Hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), 2,2'4,4'-tetrabromodiphenyl ether (BDE-47), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), di(2ethylhexyl)phthalate (DEHP), and bisphenol S (BPS) were obtained after mixture dosing in rabbits using a sparse sampling design. Data were comprehensively analyzed using nonlinear mixed effect (NLME) modeling. RESULTS The short persistence of BPS and of the DEHP metabolite (mono-2-ethylhexyl phthalate), reflected by their mean residence times (MRT) of a few hours, was due to their efficient clearance (CL, 3.2 and 0.47L/kg/h). The longer MRT of the other compounds (1-48 d) resulted either from their extremely low clearance (lower than 0.01L/kg/h for PFOA and PFOS) or from their very large volume of distribution (VSS) ranging from 33 to 45L/kg. Estimates of CL, VSS, and bioavailability were used to compute the oral loading and daily maintenance doses required to attain a nominal steady-state serum concentration of 1 ng/mL. Simulations with the NLME model were applied to predict the serum concentration profile and to contrast the differential rates of accumulation in the central vs. peripheral compartments. CONCLUSION NLME modeling of the IV and oral TK of hazardous environmental contaminants, in rabbits while fulfilling the 4R rule, was able to provide the physiological basis for interspecies extrapolation of exposure rates in a TK/TD approach to risk assessment. https://doi.org/10.1289/EHP8957.
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Affiliation(s)
- Véronique Gayrard
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Jessika Moreau
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
- Médecine de la Reproduction, Hôpital Paule de Viguier, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Nicole Picard-Hagen
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
| | - Virginie Helies
- GenPhySE, INRA, Université de Toulouse, INPT, ENVT, Castanet Tolosan, France
| | | | | | - Pierre-Louis Toutain
- INTHERES, Université de Toulouse, INRA, ENVT, Toulouse, France
- The Royal Veterinary College, University of London, London, UK
| | - Roger Leandri
- ToxAlim (Research Center in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, Toulouse, France
- Médecine de la Reproduction, Hôpital Paule de Viguier, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
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Andersen ME, Mallick P, Clewell HJ, Yoon M, Olsen GW, Longnecker MP. Using quantitative modeling tools to assess pharmacokinetic bias in epidemiological studies showing associations between biomarkers and health outcomes at low exposures. ENVIRONMENTAL RESEARCH 2021; 197:111183. [PMID: 33887277 DOI: 10.1016/j.envres.2021.111183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/07/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Biomarkers of exposure can be measured at lower and lower levels due to advances in analytical chemistry. Using these sensitive methods, some epidemiology studies report associations between biomarkers and health outcomes at biomarker levels much below those associated with effects in animal studies. While some of these low exposure associations may arise from increased sensitivity of humans compared with animals or from species-specific responses, toxicology studies with drugs, commodity chemicals and consumer products have not generally indicated significantly greater sensitivity of humans compared with test animals for most health outcomes. In some cases, these associations may be indicative of pharmacokinetic (PK) bias, i.e., a situation where a confounding factor or the health outcome itself alters pharmacokinetic processes affecting biomarker levels. Quantitative assessment of PK bias combines PK modeling and statistical methods describing outcomes across large numbers of individuals in simulated populations. Here, we first provide background on the types of PK models that can be used for assessing biomarker levels in human population and then outline a process for considering PK bias in studies intended to assess associations between biomarkers and health outcomes at low levels of exposure. After providing this background, we work through published examples where these PK methods have been applied with several chemicals/chemical classes - polychlorinated biphenyls (PCBs), perfluoroalkyl substances (PFAS), polybrominated biphenyl ethers (PBDE) and phthalates - to assess the possibility of PK bias. Studies of the health effects of low levels of exposure will be improved by developing some confidence that PK bias did not play significant roles in the observed associations.
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Campbell JL, Otter R, Anderson WA, Longnecker MP, Clewell RA, North C, Clewell HJ. Development of a physiologically based pharmacokinetic model of diisononyl phthalate (DiNP) in pregnant rat and human. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2020; 83:631-648. [PMID: 32757748 DOI: 10.1080/15287394.2020.1798831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A physiologically based pharmacokinetic (PBPK) model for di-isononyl phthalate (DiNP) was developed by adapting the existing models for di(2-ethylhexyl) phthalate (DEHP) and di-butylphthalate (DBP). Both pregnant rat and human time-course plasma and urine data were used to address the hydrolysis of DiNP in intestinal tract, plasma, and liver as well as hepatic oxidative metabolism and conjugation of the monoester and primary oxidative metabolites. Data in both rats and humans were available to inform the uptake and disposition of mono-isononyl phthalate (MiNP) as well as the three primary oxidative metabolites including hydroxy (7-OH)-, oxo (7-OXO)-, and carboxy (7-COX)-monoisononyl phthalate in plasma and urine. The DiNP model was reliable over a wide range of exposure levels in the pregnant rat as well as the two low exposure levels in humans including capturing the nonlinear behavior in the pregnant rat after repeated 750 mg/kg/day dosing. The presented DiNP PBPK model in pregnant rat and human, based upon an extensive kinetic dataset in both species, may provide a basis for assessing human equivalent exposures based upon either rodent or in vitro points of departure.
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Affiliation(s)
| | - Rainer Otter
- Regulatory Affairs/Advocacy, Basf Se , Ludwigshafen, Germany
| | - Warwick A Anderson
- Food Safety, Fera Science Ltd., National Agri-Food Innovation Campus , York, UK
| | | | | | - Colin North
- Toxicology & Environmental Science, ExxonMobil Biomedical Sciences, Inc , Annandale, NJ, USA
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Application of a combined aggregate exposure pathway and adverse outcome pathway (AEP-AOP) approach to inform a cumulative risk assessment: A case study with phthalates. Toxicol In Vitro 2020; 66:104855. [PMID: 32278033 DOI: 10.1016/j.tiv.2020.104855] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 03/26/2020] [Accepted: 04/05/2020] [Indexed: 12/20/2022]
Abstract
Advancements in measurement and modeling capabilities are providing unprecedented access to estimates of chemical exposure and bioactivity. With this influx of new data, there is a need for frameworks that help organize and disseminate information on chemical hazard and exposure in a manner that is accessible and transparent. A case study approach was used to demonstrate integration of the Adverse Outcome Pathway (AOP) and Aggregate Exposure Pathway (AEP) frameworks to support cumulative risk assessment of co-exposure to two phthalate esters that are ubiquitous in the environment and that are associated with disruption of male sexual development in the rat: di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP). A putative AOP was developed to guide selection of an in vitro assay for derivation of bioactivity values for DEHP and DnBP and their metabolites. AEPs for DEHP and DnBP were used to extract key exposure data as inputs for a physiologically based pharmacokinetic (PBPK) model to predict internal metabolite concentrations. These metabolite concentrations were then combined using in vitro-based relative potency factors for comparison with an internal dose metric, resulting in an estimated margin of safety of ~13,000. This case study provides an adaptable workflow for integrating exposure and toxicity data by coupling AEP and AOP frameworks and using in vitro and in silico methodologies for cumulative risk assessment.
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8
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Domínguez-Romero E, Scheringer M. A review of phthalate pharmacokinetics in human and rat: what factors drive phthalate distribution and partitioning? Drug Metab Rev 2019; 51:314-329. [DOI: 10.1080/03602532.2019.1620762] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Elena Domínguez-Romero
- Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin Scheringer
- Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic
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Sarigiannis DA, Karakitsios S, Dominguez-Romero E, Papadaki K, Brochot C, Kumar V, Schuhmacher M, Sy M, Mielke H, Greiner M, Mengelers M, Scheringer M. Physiology-based toxicokinetic modelling in the frame of the European Human Biomonitoring Initiative. ENVIRONMENTAL RESEARCH 2019; 172:216-230. [PMID: 30818231 DOI: 10.1016/j.envres.2019.01.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/25/2019] [Accepted: 01/28/2019] [Indexed: 06/09/2023]
Abstract
Given the opportunities provided by internal dosimetry modelling in the interpretation of human biomonitoring (HBM) data, the assessment of the links between exposure to chemicals and observed HBM data can be effectively supported by PBTK modelling. This paper gives a comprehensive review of available human PBTK models for compounds selected as a priority by the European Human Biomonitoring Initiative (HBM4EU). We highlight their advantages and deficiencies and suggest steps for advanced internal dose modelling. The review of the available PBTK models highlighted the conceptual differences between older models compared to the ones developed recently, reflecting commensurate differences in research questions. Due to the lack of coordinated strategies for deriving useful biomonitoring data for toxicokinetic properties, significant problems in model parameterisation still remain; these are further increased by the lack of human toxicokinetic data due to ethics issues. Finally, questions arise as well as to the extent they are really representative of interindividual variability. QSARs for toxicokinetic properties is a complementary approach for PBTK model parameterisation, especially for data poor chemicals. This approach could be expanded to model chemico-biological interactions such as intestinal absorption and renal clearance; this could serve the development of more complex generic PBTK models that could be applied to newly derived chemicals. Another gap identified is the framework for mixture interaction terms among compounds that could eventually interact in metabolism. From the review it was concluded that efforts should be shifted toward the development of generic multi-compartmental and multi-route models, supported by targeted biomonitoring coupled with parameterisation by both QSAR approach and experimental (in-vivo and in-vitro) data for newly developed and data poor compounds.
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Affiliation(s)
- Dimosthenis A Sarigiannis
- Aristotle University of Thessaloniki, Department of Chemical Engineering, Environmental Engineering Laboratory, University Campus, Thessaloniki 54124, Greece; HERACLES Research Center on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Balkan Center, Bldg. B, 10th km Thessaloniki-Thermi Road, 57001, Greece.
| | - Spyros Karakitsios
- Aristotle University of Thessaloniki, Department of Chemical Engineering, Environmental Engineering Laboratory, University Campus, Thessaloniki 54124, Greece; HERACLES Research Center on the Exposome and Health, Center for Interdisciplinary Research and Innovation, Balkan Center, Bldg. B, 10th km Thessaloniki-Thermi Road, 57001, Greece
| | | | - Krystalia Papadaki
- Aristotle University of Thessaloniki, Department of Chemical Engineering, Environmental Engineering Laboratory, University Campus, Thessaloniki 54124, Greece
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10
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Klein D, Kessler W, Pütz C, Semder B, Kirchinger W, Langsch A, Gries W, Otter R, Gallien A, Wurzenberger X, Filser J. Single ingestion of di-(2-propylheptyl) phthalate (DPHP) by male volunteers: DPHP in blood and its metabolites in blood and urine. Toxicol Lett 2018; 294:105-115. [DOI: 10.1016/j.toxlet.2018.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/16/2018] [Accepted: 05/08/2018] [Indexed: 10/16/2022]
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11
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Campbell JL, Yoon M, Ward PL, Fromme H, Kessler W, Phillips MB, Anderson WA, Clewell HJ, Longnecker MP. Excretion of Di-2-ethylhexyl phthalate (DEHP) metabolites in urine is related to body mass index because of higher energy intake in the overweight and obese. ENVIRONMENT INTERNATIONAL 2018; 113:91-99. [PMID: 29421411 DOI: 10.1016/j.envint.2018.01.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/12/2018] [Accepted: 01/22/2018] [Indexed: 05/20/2023]
Abstract
A higher body mass index (BMI) has been positively associated with the rate of excretion of di-2-ethylhexyl phthalate (DEHP) metabolites in urine in data from the National Health and Nutrition Examination Survey (NHANES), suggesting an association between DEHP exposure and BMI. The association, however, may be due to the association between body mass maintenance and higher energy intake, with higher energy intake being accompanied by a higher intake of DEHP. To examine this hypothesis, we ran a Monte Carlo simulation with a DEHP physiologically-based pharmacokinetic (PBPK) model for adult humans. A realistic exposure sub-model was used, which included the relation of body weight to energy intake and of energy intake to DEHP intake. The model simulation output, when compared with urinary metabolite data from NHANES, supported good model validity. The distribution of BMI in the simulated population closely resembled that in the NHANES population. This indicated that the simulated subjects and DEHP exposure model were closely aligned with the NHANES population of interest. In the simulated population, the ordinary least squares regression coefficient for log(BMI) as a function of log(DEHP nmol/min) was 0.048 (SE 0.001), as compared with the reported value of 0.019 (SE 0.005). In other words, given our model structure, the higher energy intake in the overweight and obese, and the concomitant higher DEHP exposure, describes the reported relationship between BMI and DEHP.
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Affiliation(s)
| | - Miyoung Yoon
- ScitoVation, LLC, Research Triangle Park, NC 27709, USA
| | - Peyton L Ward
- Ramboll Environ, Research Triangle Park, NC 27709, USA
| | - Hermann Fromme
- Bavarian Health and Food Safety Authority, Munich, Germany
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12
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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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Moreau M, Leonard J, Phillips KA, Campbell J, Pendse SN, Nicolas C, Phillips M, Yoon M, Tan YM, Smith S, Pudukodu H, Isaacs K, Clewell H. Using exposure prediction tools to link exposure and dosimetry for risk-based decisions: A case study with phthalates. CHEMOSPHERE 2017; 184:1194-1201. [PMID: 28672700 PMCID: PMC6084441 DOI: 10.1016/j.chemosphere.2017.06.098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/15/2017] [Accepted: 06/23/2017] [Indexed: 05/22/2023]
Abstract
A few different exposure prediction tools were evaluated for use in the new in vitro-based safety assessment paradigm using di-2-ethylhexyl phthalate (DEHP) and dibutyl phthalate (DnBP) as case compounds. Daily intake of each phthalate was estimated using both high-throughput (HT) prediction models such as the HT Stochastic Human Exposure and Dose Simulation model (SHEDS-HT) and the ExpoCast heuristic model and non-HT approaches based on chemical specific exposure estimations in the environment in conjunction with human exposure factors. Reverse dosimetry was performed using a published physiologically based pharmacokinetic (PBPK) model for phthalates and their metabolites to provide a comparison point. Daily intakes of DEHP and DnBP were estimated based on the urinary concentrations of their respective monoesters, mono-2-ethylhexyl phthalate (MEHP) and monobutyl phthalate (MnBP), reported in NHANES (2011-2012). The PBPK-reverse dosimetry estimated daily intakes at the 50th and 95th percentiles were 0.68 and 9.58 μg/kg/d and 0.089 and 0.68 μg/kg/d for DEHP and DnBP, respectively. For DEHP, the estimated median from PBPK-reverse dosimetry was about 3.6-fold higher than the ExpoCast estimate (0.68 and 0.18 μg/kg/d, respectively). For DnBP, the estimated median was similar to that predicted by ExpoCast (0.089 and 0.094 μg/kg/d, respectively). The SHEDS-HT prediction of DnBP intake from consumer product pathways alone was higher at 0.67 μg/kg/d. The PBPK-reverse dosimetry-estimated median intake of DEHP and DnBP was comparable to values previously reported for US populations. These comparisons provide insights into establishing criteria for selecting appropriate exposure prediction tools for use in an integrated modeling platform to link exposure to health effects.
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Affiliation(s)
- Marjory Moreau
- Scitovation, 6 Davis Drive, Durham, NC 27709, United States
| | - Jeremy Leonard
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd, Oak Ridge, TN 37830, United States
| | - Katherine A Phillips
- National Exposure Research Laboratory, US Environmental Protection Agency, 109 TW Alexander Dr, Durham, NC 27709, United States
| | - Jerry Campbell
- Ramboll Environ, 6 Davis Drive, Durham, NC 27709, United States
| | - Salil N Pendse
- Scitovation, 6 Davis Drive, Durham, NC 27709, United States
| | | | | | - Miyoung Yoon
- Scitovation, 6 Davis Drive, Durham, NC 27709, United States.
| | - Yu-Mei Tan
- National Exposure Research Laboratory, US Environmental Protection Agency, 109 TW Alexander Dr, Durham, NC 27709, United States.
| | - Sherrie Smith
- North Carolina State University, Raleigh, NC 27695, United States
| | - Harish Pudukodu
- North Carolina State University, Raleigh, NC 27695, United States
| | - Kristin Isaacs
- National Exposure Research Laboratory, US Environmental Protection Agency, 109 TW Alexander Dr, Durham, NC 27709, United States
| | - Harvey Clewell
- Scitovation, 6 Davis Drive, Durham, NC 27709, United States
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14
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A global human health risk assessment for octamethylcyclotetrasiloxane (D 4). Toxicol Lett 2017; 279 Suppl 1:23-41. [PMID: 28522410 DOI: 10.1016/j.toxlet.2017.05.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 05/05/2017] [Accepted: 05/15/2017] [Indexed: 11/20/2022]
Abstract
Octamethylcyclotetrasiloxane (D4) is a low-molecular-weight volatile cyclic siloxane, primarily used as an intermediate in the production of some widely-used industrial and consumer silicone based polymers and may be present as a component in a variety of consumer products. A global "harmonized" risk assessment was conducted to meet requirements for substance-specific risk assessments conducted by regulatory agencies such as USEPA's Integrated Risk Information System (IRIS), Health Canada's Chemical Management Program (CMP) and various independent scientific committees of the European Commission (e.g. the Scientific Committee on Consumer Safety (SCCS), the Scientific Committee on Health and Environmental Risks (SCHER)), as well as to provide guidance for chemical safety assessments under REACH in Europe. This risk assessment incorporates global exposure information combined with a Monte Carlo analysis to determine the most significant routes of exposure. Utilization of a multi-species, multi-route physiologically based pharmacokinetic (PBPK) model was included to estimate internal dose metrics, benchmark modeling was used to determine a point of departure (POD), and a margin of safety (MOS) evaluation was used to compare the estimates of intake with the POD. Because of the specific pharmacokinetic behaviors of D4 including high lipophilicity, high volatility with low blood-to-air partition coefficients and an extensive metabolic clearance that regulates tissue dose after exposure, the use of a PBPK model was essential to provide a comparison of a dose metric that reflects these processes. The characterization of the potential for adverse effects after exposure to D4 using a MOS approach based on an internal dose metric removes the subjective application of varying uncertainty factors from various regulatory agencies and allows examination of the differences between internal dose metrics associated with exposure and those associated with adverse effects.
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15
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Pease CK, Gentry RP. Systematic review in chemical risk assessment - A chemical industry perspective. ENVIRONMENT INTERNATIONAL 2016; 92-93:574-7. [PMID: 26705743 DOI: 10.1016/j.envint.2015.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/27/2015] [Accepted: 12/09/2015] [Indexed: 06/05/2023]
Abstract
This commentary provides a perspective from the chemicals industry on the potential usefulness of systematic review approaches in chemical risk assessment.
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Affiliation(s)
- Camilla K Pease
- Ramboll Environ, 1 Broad Gate, The Headrow, Leeds, LS1 8EQ, UK.
| | - Robinan P Gentry
- Ramboll Environ, 1900 N. 18th Street, Suite 804, Monroe, LA, USA
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Franzen A, Van Landingham C, Greene T, Plotzke K, Gentry R. A global human health risk assessment for Decamethylcyclopentasiloxane (D5). Regul Toxicol Pharmacol 2016; 74 Suppl:S25-43. [DOI: 10.1016/j.yrtph.2015.10.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/21/2015] [Accepted: 10/23/2015] [Indexed: 11/17/2022]
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17
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Rigden M, Pelletier G, Poon R, Zhu J, Auray-Blais C, Gagnon R, Kubwabo C, Kosarac I, Lalonde K, Cakmak S, Xiao B, Leingartner K, Ku KL, Bose R, Jiao J. Assessment of urinary metabolite excretion after rat acute exposure to perfluorooctanoic acid and other peroxisomal proliferators. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2015; 68:148-58. [PMID: 25015730 DOI: 10.1007/s00244-014-0058-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/26/2014] [Indexed: 05/28/2023]
Abstract
Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant. Activation of the peroxisome proliferator activated receptor alpha (PPARα) resulting from exposure to PFOA has been extensively studied in rodents. However, marked differences in response to peroxisome proliferators prevent extrapolation of rodent PPARα activation to human health risks and additional molecular mechanisms may also be involved in the biological response to PFOA exposure. To further explore the potential involvement of such additional pathways, the effects of PFOA exposure on urinary metabolites were directly compared with those of other well-known PPARα agonists. Male rats were administered PFOA (10, 33, or 100 mg/kg/d), fenofibrate (100 mg/kg/d), or di(2-ethylhexyl) phthalate (100 mg/kg/d) by gavage for 3 consecutive days and allowed to recover for 4 days, and overnight urine was collected. Greater urinary output was observed exclusively in PFOA-treated rats as the total fraction of PFOA excreted in urine increased with the dose administered. Assessment of urinary metabolites (ascorbic acid, quinolinic acid, 8-hydroxy-2'-deoxyguanosine, and malondialdehyde) provided additional information on PFOA's effects on hepatic glucuronic acid and tryptophan-nicotinamide adenine dinucleotide (NAD) pathways and on oxidative stress, whereas increased liver weight and palmitoyl-CoA oxidase activity indicative of PPARα activation and peroxisomal proliferation persisted up to day five after the last exposure.
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Balbuena P, Campbell J, Clewell HJ, Clewell RA. Evaluation of a predictive in vitro Leydig cell assay for anti-androgenicity of phthalate esters in the rat. Toxicol In Vitro 2013; 27:1711-8. [DOI: 10.1016/j.tiv.2013.03.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 03/26/2013] [Accepted: 03/31/2013] [Indexed: 11/28/2022]
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19
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Shiue I. Urinary environmental chemical concentrations and vitamin D are associated with vision, hearing, and balance disorders in the elderly. ENVIRONMENT INTERNATIONAL 2013; 53:41-46. [PMID: 23314200 DOI: 10.1016/j.envint.2012.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 12/09/2012] [Accepted: 12/14/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND Acute exposure to environmental chemicals can result in loss of consciousness and upon recovery neurological symptoms, but little evidence exists in large epidemiological human studies. Hence, it was aimed to determine the relationships between urinary environmental chemicals (including heavy metals, environmental bisphenols, pesticides, arsenic, and phthalates) concentrations and vision, hearing, and balance disorders in a national population-based setting. METHODS United States National Health and Nutrition Examination Surveys is a national population-based multi-year cross-sectional study. Information on demographics and vision, hearing, and balance disorders was obtained by household interview using questionnaires in the 2003-2004 cohort (aged 50 and above). Urinary environmental chemicals were detected by mass spectrometry in selected but representative people. Analyses involved logistic regression models. RESULTS Urinary cadmium, molybdenum, and tungsten concentrations, which are commonly associated with heart disease, were associated with vision disorder. Urinary 2,4,5-trichlorophenol and arsenic acid concentrations and circulating mono-n-butyl phthalate, mono-benzyl phthalate, and mono-(3-carboxypropyl) phthalate metabolites were significantly associated with hearing disorder. Moreover, urinary barium and 4-tert-octyl-phenol concentrations were associated with balance disorder. People who had ears ringing, roaring, or buzzing in the past year tended to have higher urinary barium, 2,4-dichlorophenol, and mono-benzyl phthalate concentrations. DISCUSSION Significant correlations were observed in urinary environmental chemicals and neurobehavioural impairment for the first time. However, the causation cannot be established due to its cross-sectional study design. Future studies with a longitudinal aspect and/or in clinical trials are warranted to clearly understand the biological mechanism along the pathway before drawing a firm conclusion on these relationships.
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Affiliation(s)
- Ivy Shiue
- European Centre for Environment and Human Health, University of Exeter, UK.
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20
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Clewell RA, Sochaski M, Edwards K, Creasy DM, Willson G, Andersen ME. Disposition of diiosononyl phthalate and its effects on sexual development of the male fetus following repeated dosing in pregnant rats. Reprod Toxicol 2013; 35:56-69. [DOI: 10.1016/j.reprotox.2012.07.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 06/27/2012] [Accepted: 07/03/2012] [Indexed: 10/28/2022]
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21
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Kessler W, Numtip W, Völkel W, Seckin E, Csanády GA, Pütz C, Klein D, Fromme H, Filser JG. Kinetics of di(2-ethylhexyl) phthalate (DEHP) and mono(2-ethylhexyl) phthalate in blood and of DEHP metabolites in urine of male volunteers after single ingestion of ring-deuterated DEHP. Toxicol Appl Pharmacol 2012; 264:284-91. [DOI: 10.1016/j.taap.2012.08.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 11/30/2022]
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