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Streekstra EJ, Keuper-Navis M, van den Heuvel JJWM, van den Broek P, Greupink R, Stommel MWJ, de Boode WP, Botden SMBI, Russel FGM, van de Steeg E, de Wildt SN. The potential of enteroids derived from children and adults to study age-dependent differences in intestinal CYP3A4/5 metabolism. Eur J Pharm Sci 2024; 201:106868. [PMID: 39084538 DOI: 10.1016/j.ejps.2024.106868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 07/12/2024] [Accepted: 07/27/2024] [Indexed: 08/02/2024]
Abstract
Drug metabolism in the intestinal wall affects bioavailability of orally administered drugs and is influenced by age. Hence, it is important to fully understand the drug metabolizing capacity of the gut to predict systemic exposure. The aim of this study was to investigate the potential of enteroids as a tool to study CYP3A4/5 -mediated metabolism in both children and adults. Bioconversion of midazolam, a CYP3A4/5 model substrate, was studied using enteroid monolayers as well as tissue explants in the Ussing chamber, both derived from pediatric [median (range age): 54 weeks (2 days - 13 years), n = 21] and adult (n = 5) tissue. Caco-2 cellular monolayers were employed as controls. In addition, mRNA expression of CYP3A4 was determined in enteroid monolayers (n = 11), tissue (n = 23) and Caco-2 using RT-qPCR. Midazolam metabolism was successfully detected in all enteroid monolayers, as well as in all tissue explants studied in the Ussing chamber, whereas Caco-2 showed no significant metabolite formation. The extracted fraction of midazolam was similar between enteroid monolayers and tissue. The fraction of midazolam extracted increased with age in enteroid monolayers derived from 0 to 70 week old donors. No statistically significant correlation was observed in tissue likely due to high variability observed and the smaller donor numbers included in the study. At the level of gene expression, CYP3A4 increased with age in tissues (n = 32), while this was not reflected in enteroid monolayers (n = 16). Notably, asymmetric metabolite formation was observed in enteroids and tissue, with higher metabolite formation on the luminal side of the barrier. In summary, we demonstrated that enteroids can be used to measure CYP3A4/5 midazolam metabolism, which we show is similar as observed in fresh isolated tissue. This was the case both in children and adults, indicating the potential of enteroids to predict intestinal metabolism. This study provides promising data to further develop enteroids to study drug metabolism in vitro and potentially predict oral absorption for special populations as an alternative to using fresh tissue.
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Affiliation(s)
- Eva J Streekstra
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Leiden, the Netherlands
| | - Marit Keuper-Navis
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Leiden, the Netherlands; Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, the Netherlands
| | - Jeroen J W M van den Heuvel
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Petra van den Broek
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rick Greupink
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Martijn W J Stommel
- Department of Surgery, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Willem P de Boode
- Department of Pediatrics, Division of Neonatology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, the Netherlands
| | - Sanne M B I Botden
- Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans G M Russel
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Evita van de Steeg
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Leiden, the Netherlands
| | - Saskia N de Wildt
- Division of Pharmacology and Toxicology, Department of Pharmacy, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Intensive Care, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Neonatal and Pediatric Intensive Care, Erasmus MC Sophia Children's Hospital, Rotterdam, the Netherlands.
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2
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Zhang M, Vuist IM, Rottschäfer V, de Lange EC. Exploring K p,uu,BBB values smaller than unity in remoxipride: A physiologically-based CNS model approach highlighting brain metabolism in drugs with passive blood-brain barrier transport. Eur J Pharm Sci 2024; 203:106883. [PMID: 39181172 DOI: 10.1016/j.ejps.2024.106883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 08/21/2024] [Indexed: 08/27/2024]
Abstract
(AIM) Kp,uu,BBB values are crucial indicators of drug distribution into the brain, representing the steady-state relationship between unbound concentrations in plasma and in brain extracellular fluid (brainECF). Kp,uu,BBB values < 1 are often interpreted as indicators of dominant active efflux transport processes at the blood-brain barrier (BBB). However, the potential impact of brain metabolism on this value is typically not addressed. In this study, we investigated the brain distribution of remoxipride, as a paradigm compound for passive BBB transport with yet unexplained brain elimination that was hypothesized to represent brain metabolism. (METHODS) The physiologically-based LeiCNS pharmacokinetic predictor (LeiCNS-PK model) was used to compare brain distribution of remoxipride with and without Michaelis-Menten kinetics at the BBB and/or brain cell organelle levels. To that end, multiple in-house (IV 0.7, 3.5, 4, 5.2, 7, 8, 14 and 16 mg kg-1) and external (IV 4 and 8 mg kg-1) rat microdialysis studies plasma and brainECF data were analysed. (RESULTS) The incorporation of active elimination through presumed brain metabolism of remoxipride in the LeiCNS-PK model significantly improved the prediction accuracy of experimentally observed brainECF profiles of this drug. The model integrated with brain metabolism in both barriers and organelles levels is named LeiCNS-PK3.5. (CONCLUSION) For drugs with Kp,uu,BBB values < 1, not only the current interpretation of dominant BBB efflux transport, but also potential brain metabolism needs to be considered, especially because these may be concentration dependent. This will improve the mechanistic understanding of the processes that determine brain PK profiles.
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Affiliation(s)
- Mengxu Zhang
- Division of Systems Pharmacology and Pharmacy, Predictive Pharmacology Group, Leiden Academic Centre of Drug Research, Leiden University, Gorlaeus Laboratories, Leiden, the Netherlands
| | - Ilona M Vuist
- Charles River Laboratories, Groningen, the Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Leiden, the Netherlands; Korteweg-de Vries Institute for Mathematics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, the Netherlands
| | - Elizabeth Cm de Lange
- Division of Systems Pharmacology and Pharmacy, Predictive Pharmacology Group, Leiden Academic Centre of Drug Research, Leiden University, Gorlaeus Laboratories, Leiden, the Netherlands.
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3
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Licul-Kucera V, Ragnarsdóttir O, Frömel T, van Wezel AP, Knepper TP, Harrad S, Abou-Elwafa Abdallah M. Interspecies comparison of metabolism of two novel prototype PFAS. CHEMOSPHERE 2024; 351:141237. [PMID: 38242512 DOI: 10.1016/j.chemosphere.2024.141237] [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: 10/18/2023] [Revised: 01/11/2024] [Accepted: 01/15/2024] [Indexed: 01/21/2024]
Abstract
As a result of proposed global restrictions and regulations on current-use per-and polyfluoroalkyl substances (PFAS), research on possible alternatives is highly required. In this study, phase I in vitro metabolism of two novel prototype PFAS in human and rat was investigated. These prototype chemicals are intended to be safer-by-design and expected to mineralize completely, and thus be less persistent in the environment compared to the PFAS available on the market. Following incubation with rat liver S9 (RL-S9) fractions, two main metabolites per initial substance were produced, namely an alcohol and a short-chain carboxylic acid. While with human liver S9 (HL-S9) fractions, only the short-chain carboxylic acid was detected. Beyond these major metabolites, two and five additional metabolites were identified at very low levels by non-targeted screening for the ether- and thioether-linked prototype chemicals, respectively. Overall, complete mineralization during the in vitro hepatic metabolism of these novel PFAS by HL-S9 and RL-S9 fractions was not observed. The reaction kinetics of the surfactants was determined by using the metabolite formation, rather than the substrate depletion approach. With rat liver enzymes, the formation rates of primary metabolite alcohols were at least two orders of magnitude higher than those of secondary metabolite carboxylic acids. When incubating with human liver enzymes, the formation rates of single metabolite carboxylic acids, were similar or smaller than those experienced in rat. It also indicates that the overall metabolic rate and clearance of surfactants are significantly higher in rat liver than in human liver. The maximum formation rate of the thioether congener exceeded 10-fold that of the ether in humans but were similar in rats. Overall, the results suggest that metabolism of the prototype chemicals followed a similar trend to those reported in studies of fluorotelomer alcohols.
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Affiliation(s)
- Viktória Licul-Kucera
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands; Institute for Analytical Research, Hochschulen Fresenius Gem. Trägergesellschaft MbH, Idstein, Germany.
| | - Oddný Ragnarsdóttir
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Tobias Frömel
- Institute for Analytical Research, Hochschulen Fresenius Gem. Trägergesellschaft MbH, Idstein, Germany
| | - Annemarie P van Wezel
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | - Thomas P Knepper
- Institute for Analytical Research, Hochschulen Fresenius Gem. Trägergesellschaft MbH, Idstein, Germany
| | - Stuart Harrad
- School of Geography, Earth & Environmental Sciences, University of Birmingham, Birmingham, UK
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4
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Reiss R, Loccisano A, Deines A, Kim M, Nallani G, Chandrasekaran A, Whatling P. A physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) model for the insecticide dimethoate. Xenobiotica 2023; 53:382-395. [PMID: 37706283 DOI: 10.1080/00498254.2023.2258507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 09/10/2023] [Indexed: 09/15/2023]
Abstract
1. Dimethoate is an organophosphate insecticide that is converted in vivo to omethoate, the active toxic moiety. Omethoate inhibits acetylcholinesterase (AChE) in the brain and red blood cells (RBCs). This paper describes the development of rat and human physiologically-based pharmacokinetic/pharmacodynamic (PBPK/PD) models for dimethoate.2. The model simulates the absorption and distribution of dimethoate and omethoate, the conversion of dimethoate to omethoate and to other metabolites, the metabolism and excretion of omethoate, and the inhibition of RBC and brain AChE. An extensive data collection program to estimate metabolism and inhibition parameters is described.3. The suite of models includes an adult rat, post-natal rat, and human model. The rat models were evaluated by comparing model predictions of dimethoate and omethoate to measured blood time course data, and with RBC and brain AChE inhibition estimates from an extensive database of in vivo AChE measurements.4. After the demonstration of adequately fitted rat models that were robust to sensitivity analysis, the human model was applied for estimation of points-of-departure (PODs) for risk assessment using the human-specific parameters in the human PBPK/PD model. Thus, the standard interspecies uncertainty factor can be reduced from 10X to 1X.
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5
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Deepika D, Kumar V. The Role of "Physiologically Based Pharmacokinetic Model (PBPK)" New Approach Methodology (NAM) in Pharmaceuticals and Environmental Chemical Risk Assessment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3473. [PMID: 36834167 PMCID: PMC9966583 DOI: 10.3390/ijerph20043473] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/10/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Physiologically Based Pharmacokinetic (PBPK) models are mechanistic tools generally employed in the pharmaceutical industry and environmental health risk assessment. These models are recognized by regulatory authorities for predicting organ concentration-time profiles, pharmacokinetics and daily intake dose of xenobiotics. The extension of PBPK models to capture sensitive populations such as pediatric, geriatric, pregnant females, fetus, etc., and diseased populations such as those with renal impairment, liver cirrhosis, etc., is a must. However, the current modelling practices and existing models are not mature enough to confidently predict the risk in these populations. A multidisciplinary collaboration between clinicians, experimental and modeler scientist is vital to improve the physiology and calculation of biochemical parameters for integrating knowledge and refining existing PBPK models. Specific PBPK covering compartments such as cerebrospinal fluid and the hippocampus are required to gain mechanistic understanding about xenobiotic disposition in these sub-parts. The PBPK model assists in building quantitative adverse outcome pathways (qAOPs) for several endpoints such as developmental neurotoxicity (DNT), hepatotoxicity and cardiotoxicity. Machine learning algorithms can predict physicochemical parameters required to develop in silico models where experimental data are unavailable. Integrating machine learning with PBPK carries the potential to revolutionize the field of drug discovery and development and environmental risk. Overall, this review tried to summarize the recent developments in the in-silico models, building of qAOPs and use of machine learning for improving existing models, along with a regulatory perspective. This review can act as a guide for toxicologists who wish to build their careers in kinetic modeling.
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Affiliation(s)
- Deepika Deepika
- Environmental Engineering Laboratory, Departament d’Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia, Spain
- Pere Virgili Health Research Institute (IISPV), Hospital Universitari Sant Joan de Reus, Universitat Rovira i Virgili, 43204 Reus, Catalonia, Spain
| | - Vikas Kumar
- Environmental Engineering Laboratory, Departament d’Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia, Spain
- Pere Virgili Health Research Institute (IISPV), Hospital Universitari Sant Joan de Reus, Universitat Rovira i Virgili, 43204 Reus, Catalonia, Spain
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Chang X, Tan YM, Allen DG, Bell S, Brown PC, Browning L, Ceger P, Gearhart J, Hakkinen PJ, Kabadi SV, Kleinstreuer NC, Lumen A, Matheson J, Paini A, Pangburn HA, Petersen EJ, Reinke EN, Ribeiro AJS, Sipes N, Sweeney LM, Wambaugh JF, Wange R, Wetmore BA, Mumtaz M. IVIVE: Facilitating the Use of In Vitro Toxicity Data in Risk Assessment and Decision Making. TOXICS 2022; 10:232. [PMID: 35622645 PMCID: PMC9143724 DOI: 10.3390/toxics10050232] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 04/24/2022] [Indexed: 02/04/2023]
Abstract
During the past few decades, the science of toxicology has been undergoing a transformation from observational to predictive science. New approach methodologies (NAMs), including in vitro assays, in silico models, read-across, and in vitro to in vivo extrapolation (IVIVE), are being developed to reduce, refine, or replace whole animal testing, encouraging the judicious use of time and resources. Some of these methods have advanced past the exploratory research stage and are beginning to gain acceptance for the risk assessment of chemicals. A review of the recent literature reveals a burst of IVIVE publications over the past decade. In this review, we propose operational definitions for IVIVE, present literature examples for several common toxicity endpoints, and highlight their implications in decision-making processes across various federal agencies, as well as international organizations, including those in the European Union (EU). The current challenges and future needs are also summarized for IVIVE. In addition to refining and reducing the number of animals in traditional toxicity testing protocols and being used for prioritizing chemical testing, the goal to use IVIVE to facilitate the replacement of animal models can be achieved through their continued evolution and development, including a strategic plan to qualify IVIVE methods for regulatory acceptance.
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Affiliation(s)
- Xiaoqing Chang
- Inotiv-RTP, 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA; (X.C.); (D.G.A.); (S.B.); (L.B.); (P.C.)
| | - Yu-Mei Tan
- U.S. Environmental Protection Agency, Office of Pesticide Programs, 109 T.W. Alexander Drive, Durham, NC 27709, USA;
| | - David G. Allen
- Inotiv-RTP, 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA; (X.C.); (D.G.A.); (S.B.); (L.B.); (P.C.)
| | - Shannon Bell
- Inotiv-RTP, 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA; (X.C.); (D.G.A.); (S.B.); (L.B.); (P.C.)
| | - Paul C. Brown
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Silver Spring, MD 20903, USA; (P.C.B.); (A.J.S.R.); (R.W.)
| | - Lauren Browning
- Inotiv-RTP, 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA; (X.C.); (D.G.A.); (S.B.); (L.B.); (P.C.)
| | - Patricia Ceger
- Inotiv-RTP, 601 Keystone Park Drive, Suite 200, Morrisville, NC 27560, USA; (X.C.); (D.G.A.); (S.B.); (L.B.); (P.C.)
| | - Jeffery Gearhart
- The Henry M. Jackson Foundation, Air Force Research Laboratory, 711 Human Performance Wing, Wright-Patterson Air Force Base, OH 45433, USA;
| | - Pertti J. Hakkinen
- National Library of Medicine, National Center for Biotechnology Information, 8600 Rockville Pike, Bethesda, MD 20894, USA;
| | - Shruti V. Kabadi
- U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Additive Safety, 5001 Campus Drive, HFS-275, College Park, MD 20740, USA;
| | - Nicole C. Kleinstreuer
- National Institute of Environmental Health Sciences, National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, P.O. Box 12233, Research Triangle Park, NC 27709, USA;
| | - Annie Lumen
- U.S. Food and Drug Administration, National Center for Toxicological Research, 3900 NCTR Road, Jefferson, AR 72079, USA;
| | - Joanna Matheson
- U.S. Consumer Product Safety Commission, Division of Toxicology and Risk Assessment, 5 Research Place, Rockville, MD 20850, USA;
| | - Alicia Paini
- European Commission, Joint Research Centre (JRC), 21027 Ispra, Italy;
| | - Heather A. Pangburn
- Air Force Research Laboratory, 711 Human Performance Wing, 2729 R Street, Area B, Building 837, Wright-Patterson Air Force Base, OH 45433, USA;
| | - Elijah J. Petersen
- U.S. Department of Commerce, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA;
| | - Emily N. Reinke
- U.S. Army Public Health Center, 8252 Blackhawk Rd., Aberdeen Proving Ground, MD 21010, USA;
| | - Alexandre J. S. Ribeiro
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Silver Spring, MD 20903, USA; (P.C.B.); (A.J.S.R.); (R.W.)
| | - Nisha Sipes
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 TW Alexander Dr., Research Triangle Park, NC 27711, USA; (N.S.); (J.F.W.); (B.A.W.)
| | - Lisa M. Sweeney
- UES, Inc., 4401 Dayton-Xenia Road, Beavercreek, OH 45432, Assigned to Air Force Research Laboratory, 711 Human Performance Wing, Wright-Patterson Air Force Base, OH 45433, USA;
| | - John F. Wambaugh
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 TW Alexander Dr., Research Triangle Park, NC 27711, USA; (N.S.); (J.F.W.); (B.A.W.)
| | - Ronald Wange
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research, 10903 New Hampshire Avenue, Silver Spring, MD 20903, USA; (P.C.B.); (A.J.S.R.); (R.W.)
| | - Barbara A. Wetmore
- U.S. Environmental Protection Agency, Center for Computational Toxicology and Exposure, 109 TW Alexander Dr., Research Triangle Park, NC 27711, USA; (N.S.); (J.F.W.); (B.A.W.)
| | - Moiz Mumtaz
- Agency for Toxic Substances and Disease Registry, Office of the Associate Director for Science, 1600 Clifton Road, S102-2, Atlanta, GA 30333, USA
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Moreau M, Mallick P, Smeltz M, Haider S, Nicolas CI, Pendse SN, Leonard JA, Linakis MW, McMullen PD, Clewell RA, Clewell HJ, Yoon M. Considerations for Improving Metabolism Predictions for In Vitro to In Vivo Extrapolation. FRONTIERS IN TOXICOLOGY 2022; 4:894569. [PMID: 35573278 PMCID: PMC9099212 DOI: 10.3389/ftox.2022.894569] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/13/2022] [Indexed: 12/14/2022] Open
Abstract
High-throughput (HT) in vitro to in vivo extrapolation (IVIVE) is an integral component in new approach method (NAM)-based risk assessment paradigms, for rapidly translating in vitro toxicity assay results into the context of in vivo exposure. When coupled with rapid exposure predictions, HT-IVIVE supports the use of HT in vitro assays for risk-based chemical prioritization. However, the reliability of prioritization based on HT bioactivity data and HT-IVIVE can be limited as the domain of applicability of current HT-IVIVE is generally restricted to intrinsic clearance measured primarily in pharmaceutical compounds. Further, current approaches only consider parent chemical toxicity. These limitations occur because current state-of-the-art HT prediction tools for clearance and metabolite kinetics do not provide reliable data to support HT-IVIVE. This paper discusses current challenges in implementation of IVIVE for prioritization and risk assessment and recommends a path forward for addressing the most pressing needs and expanding the utility of IVIVE.
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Affiliation(s)
- Marjory Moreau
- ScitoVation, LLC, Durham, NC, United States
- *Correspondence: Marjory Moreau,
| | | | | | | | | | | | - Jeremy A. Leonard
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
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Abass K, Reponen P, Alsanie WF, Rautio A, Pelkonen O. Characterization of furathiocarb metabolism in in vitro human liver microsomes and recombinant cytochrome P450 enzymes. Toxicol Rep 2022; 9:679-689. [PMID: 35399214 PMCID: PMC8989696 DOI: 10.1016/j.toxrep.2022.03.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 03/08/2022] [Accepted: 03/29/2022] [Indexed: 11/18/2022] Open
Abstract
Furathiocarb is a carbamate insecticide detected in ecosystems. Its main metabolite carbofuran has been alluded to affect birth outcomes and disturb hormone levels in humans. The metabolism of furathiocarb in humans has not been characterized. The metabolism studies were performed using hepatic microsomes from ten donors and fifteen human cDNA-expressed CYPs. The initial screening and identification of the metabolites were performed by LC-TOF. Quantifications and fragmentations were performed by LC/MS-MS. Furathiocarb was metabolized to eight phase I metabolites via two general pathways, carbofuran metabolic pathway and furathiocarb oxidation pathway. Six metabolites in the carbofuran metabolic pathway (carbofuran, 3-hydroxycarbofuran, 3-ketocarbofuran, 3-keto-7-phenolcarbofuran, 3-hydroxy-7-phenolcarbofuran, and 7-phenolcarbofuran) were identified with the help of authentic standards. The two unidentified metabolites in the furathiocarb oxidation pathway are probably hydroxylated and sulfoxidated derivatives of furathiocarb. The carbofuran metabolic pathway was more predominant than the furathiocarb oxidation pathway, ratios ranged from 24- to 115-fold in a 10-donor panel of hepatic microsomes. On the basis of recombinant CYP studies, the carbofuran pathway was dominated by CYP3A4 (95.9%); contributions by CYP1A2 (1.3%) and CYP2B6 (2.0%) were minor. The minor furathiocarb oxidation pathway was catalyzed by CYP2C19 and CYP2D6 (hydroxylated/sulfoxidated metabolite A) and by CYP3A5, CYP3A4 and CYP2A6 (metabolite B). High and significant correlation between carbofuran metabolic pathway and CYP3A4 marker activities (midazolam-1'-hydroxylation and omeprazole-sulfoxidation) were observed. Ketoconazole, a CYP3A4-inhibitor, inhibited the carbofuran pathway by 32–86% and hydroxylated/sulfoxidated metabolite-B formations by 41–62%. The data suggest that in humans, the carbofuran metabolic pathway is dominant, and CYP3A4 is the major enzyme involved. These results provide useful scientific information for furathiocarb risk assessment in humans. Eight Phase I metabolites were detected by LC-TOF-MS/MS. The carbofuran pathway was more rapid than the furathiocarb oxidation pathway The carbofuran pathway was dominated by CYP3A4 (96%). Ketoconazole inhibited the carbofuran pathway by 32–86%. The findings provide useful scientific information for furathiocarb risk assessment in humans.
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Affiliation(s)
- Khaled Abass
- Arctic Health, Faculty of Medicine, University of Oulu, P.O. Box 7300, FI-90014, Finland
- Pharmacology and Toxicology Unit, Research Unit of Biomedicine, University of Oulu, P.O. Box 5000, Oulu FI-90014, Finland
- Department of Pesticides, Menoufia University, P.O. Box 32511, Egypt
- Correspondence to: Faculty of Medicine, Arctic Health, University of Oulu, Oulu FI-90014, Finland.
| | - Petri Reponen
- Pharmacology and Toxicology Unit, Research Unit of Biomedicine, University of Oulu, P.O. Box 5000, Oulu FI-90014, Finland
| | - Walaa F. Alsanie
- Department of Clinical Laboratory Sciences, The Faculty of Applied Medical Sciences & Centre of Biomedical Sciences Research (CBSR), Taif University, Saudi Arabia
| | - Arja Rautio
- Arctic Health, Faculty of Medicine, University of Oulu, P.O. Box 7300, FI-90014, Finland
- Thule Institute, University of the Arctic, Oulu FI-90014, Finland
| | - Olavi Pelkonen
- Pharmacology and Toxicology Unit, Research Unit of Biomedicine, University of Oulu, P.O. Box 5000, Oulu FI-90014, Finland
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9
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Zheng G, Webster TF, Salamova A. Quaternary Ammonium Compounds: Bioaccumulation Potentials in Humans and Levels in Blood before and during the Covid-19 Pandemic. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14689-14698. [PMID: 34662096 PMCID: PMC8547165 DOI: 10.1021/acs.est.1c01654] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 05/10/2023]
Abstract
Quaternary ammonium compounds (QACs) are commonly used in a variety of consumer, pharmaceutical, and medical products. In this study, bioaccumulation potentials of 18 QACs with alkyl chain lengths of C8-C18 were determined in the in vitro-in vivo extrapolation (IVIVE) model using the results of human hepatic metabolism and serum protein binding experiments. The slowest in vivo clearance rates were estimated for C12-QACs, suggesting that these compounds may preferentially build up in blood. The bioaccumulation of QACs was further confirmed by the analysis of human blood (sera) samples (n = 222). Fifteen out of the 18 targeted QACs were detected in blood with the ΣQAC concentrations reaching up to 68.6 ng/mL. The blood samples were collected during two distinct time periods: before the outbreak of the COVID-19 pandemic (2019; n = 111) and during the pandemic (2020, n = 111). The ΣQAC concentrations were significantly higher in samples collected during the pandemic (median 6.04 ng/mL) than in those collected before (median 3.41 ng/mL). This is the first comprehensive study on the bioaccumulation and biomonitoring of the three major QAC groups and our results provide valuable information for future epidemiological, toxicological, and risk assessment studies targeting these chemicals.
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Affiliation(s)
- Guomao Zheng
- O’Neill School of Public and Environmental Affairs, Indiana University, Bloomington 47405, United States
| | - Thomas F. Webster
- School of Public Health, Boston University, Boston, Massachusetts 02118, United States
| | - Amina Salamova
- O’Neill School of Public and Environmental Affairs, Indiana University, Bloomington 47405, United States
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10
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Wang X, Zhu Q, Liao C, Jiang G. Human internal exposure to organophosphate esters: A short review of urinary monitoring on the basis of biological metabolism research. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126279. [PMID: 34329041 DOI: 10.1016/j.jhazmat.2021.126279] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/23/2021] [Accepted: 05/29/2021] [Indexed: 06/13/2023]
Abstract
As alternatives to traditional brominated flame retardants, organophosphate flame retardants (OPFRs), especially for organophosphate esters (OPEs) -- the most widely used and investigated OPFRs, have raised people's concern on their environmental and health-related risks over the years. Considering their extensive environmental occurrence and potential adverse effects, precise estimation on the human body burden of OPEs will be conducive to the restrictions on the usage of these compounds scientifically. Biomonitoring research can provide precise information on human exposure to OPEs as it reveals the degree of external exposure from all exposure routes. Knowledge on biotransformation and metabolism of OPEs in the biosystems is of great significance for our understanding of the internal exposure to these compounds. In this study, the biological metabolic processes of nine OPEs prevalent in the environment, involving tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), tripropyl phosphate (TPrP), tri-n-butyl phosphate (TnBP), tris(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tricresyl phosphate (TCrP), are comprehensively reviewed. Specifically, the metabolic pathway, kinetics and mechanism of OPEs are depicted in detail. Under this context, the advances and limitations on biomonitoring of OPE metabolites in human urine are summarized. The requirements of specificity, quantitative stability, high detection frequency/concentration are needed for OPE metabolites to be considered and validated as biomarkers. Thus far, deeper elucidations on the metabolic processes and identification of biomarkers of OPEs are urgently required, given that some OPEs have no suitable biomarkers in human biomonitoring. For better assessment of the body burden of OPEs in humans, reliable and effective methodologies for urine sampling and estimation on internal exposure to OPEs need to be further developed in the future.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingqing Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunyang Liao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Kenyon EM. Arsenic toxicokinetic modeling and risk analysis: Progress, needs and applications. Toxicology 2021; 457:152809. [PMID: 33965444 DOI: 10.1016/j.tox.2021.152809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/05/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023]
Abstract
Arsenic (As) poses unique challenges in PBTK model development and risk analysis applications. Arsenic metabolism is complex, adequate information to attribute specific metabolites to particular adverse effects in humans is sparse, and measurement of relevant metabolites in biological media can be difficult. Multiple As PBTK models have been published and used or adapted for use in various exposure and risk analysis applications. These applications illustrate the broad utility of PBTK models for exposure and dose-response analysis, particularly for arsenic where multi-pathway, multi-route exposures and multiple toxic effects are of concern. Arsenic PBTK models have been used together with exposure reconstruction and dose-response functions to estimate risk of specific adverse health effects due to drinking water exposure and consumption of specific foodstuffs (e.g. rice, seafood), as well as to derive safe exposure levels and develop consumption advisories. Future refinements to arsenic PBTK models can enhance the confidence in such analyses. Improved estimates for methylation biotransformation parameters based on in vitro to in vivo extrapolation (IVIVE) methods and estimation of interindividual variability in key model parameters for specific toxicologically relevant metabolites are two important areas for consideration.
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Affiliation(s)
- Elaina M Kenyon
- Center for Computational Toxicology and Exposure, U.S. EPA, Office of Research and Development, Research Triangle Park, NC, United States.
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12
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Tohon H, Valcke M, Aranda-Rodriguez R, Nong A, Haddad S. Estimation of toluene exposure in air from BMA (S-benzylmercapturic acid) urinary measures using a reverse dosimetry approach based on physiologically pharmacokinetic modeling. Regul Toxicol Pharmacol 2021; 120:104860. [PMID: 33406392 DOI: 10.1016/j.yrtph.2020.104860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/14/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
This study aimed to use a reverse dosimetry PBPK modeling approach to estimate toluene atmospheric exposure from urinary measurements of S-benzylmercapturic acid (BMA) in a small group of individuals and to evaluate the uncertainty associated to urinary spot-sampling compared to 24-h collected urine samples. Each exposure assessment technique was developed namely to estimate toluene air exposure from BMA measurements in 24-h urine samples (24-h-BMA) and from distributions of daily urinary BMA spot measurements (DUBSM). Model physiological parameters were described based upon age, weight, size and sex. Monte Carlo simulations with the PBPK model allowed converting DUBSM distribution (and 24-h-BMA) into toluene air levels. For the approach relying on DUBSM distribution, the ratio between the 95% probability of predicted toluene concentration and its 50% probability in each individual varied between 1.2 and 1.4, while that based on 24-h-BMA varied between 1.0 and 1.1. This suggests more variability in estimated exposure from spot measurements. Thus, estimating toluene exposure based on DUBSM distribution generated about 20% more uncertainty. Toluene levels estimated (0.0078-0.0138 ppm) are well below Health Canada's maximum chronic air guidelines. PBPK modeling and reverse dosimetry may be combined to interpret urinary metabolites data of VOCs and assess related uncertainties.
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Affiliation(s)
- Honesty Tohon
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada
| | - Mathieu Valcke
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada; Direction de la santé environnementale et de la toxicologie, Institut national de santé publique du Québec, Montréal, Quebec, Canada
| | - Rocio Aranda-Rodriguez
- Exposure and Biomonitoring Division, Environmental Health Sciences and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Andy Nong
- Exposure and Biomonitoring Division, Environmental Health Sciences and Research Bureau, Health Canada, Ottawa, ON, Canada
| | - Sami Haddad
- Department of Environmental and Occupational Health, ESPUM, CReSP, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montreal, Qc, H3C 3J7, Canada.
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13
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Fairman K, Li M, Kabadi SV, Lumen A. Physiologically based pharmacokinetic modeling: A promising tool for translational research and regulatory toxicology. CURRENT OPINION IN TOXICOLOGY 2020. [DOI: 10.1016/j.cotox.2020.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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14
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Kenyon EM, Eklund C, Pegram RA, Lipscomb JC. Comparison of in vivo derived and scaled in vitro metabolic rate constants for several volatile organic compounds (VOCs). Toxicol In Vitro 2020; 69:105002. [PMID: 32946980 DOI: 10.1016/j.tiv.2020.105002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/26/2020] [Accepted: 09/13/2020] [Indexed: 10/23/2022]
Abstract
Metabolic rate parameters estimation using in vitro data is necessary due to numbers of chemicals for which data are needed, trend towards minimizing laboratory animal use, and limited opportunity to collect data in human subjects. We evaluated how well metabolic rate parameters derived from in vitro data predict overall in vivo metabolism for a set of environmental chemicals for which well validated and established methods exist. We compared values of VmaxC derived from in vivo vapor uptake studies with estimates of VmaxC scaled up from in vitro hepatic microsomal metabolism studies for VOCs for which data were available in male F344 rats. For 6 of 7 VOCs, differences between the in vivo and scaled up in vitro VmaxC estimates were less than 2.6-fold. For bromodichloromethane (BDCM), the in vivo derived VmaxC was approximately 4.4-fold higher than the in vitro derived and scaled up VmaxC. The more rapid rate of BDCM metabolism estimated based in vivo studies suggests other factors such as extrahepatic metabolism, binding or other non-specific losses making a significant contribution to overall clearance. Systematic and reliable utilization of scaled up in vitro biotransformation rate parameters in PBPK models will require development of methods to predict cases in which extrahepatic metabolism and binding as well as other factors are likely to be significant contributors.
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Affiliation(s)
- Elaina M Kenyon
- Center for Computational Toxicology and Exposure, U.S. EPA, Office of Research and Development, Research Triangle Park, NC, United States.
| | - Christopher Eklund
- Center for Computational Toxicology and Exposure, U.S. EPA, Office of Research and Development, Research Triangle Park, NC, United States
| | - Rex A Pegram
- Center for Computational Toxicology and Exposure, U.S. EPA, Office of Research and Development, Research Triangle Park, NC, United States
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15
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Stevens LJ, Donkers JM, Dubbeld J, Vaes WHJ, Knibbe CAJ, Alwayn IPJ, van de Steeg E. Towards human ex vivo organ perfusion models to elucidate drug pharmacokinetics in health and disease. Drug Metab Rev 2020; 52:438-454. [DOI: 10.1080/03602532.2020.1772280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lianne J. Stevens
- Department of Surgery, Division of Transplantation, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
- The Netherlands Organisation for Applied Scientific Research (TNO), Zeist, The Netherlands
| | - Joanne M. Donkers
- The Netherlands Organisation for Applied Scientific Research (TNO), Zeist, The Netherlands
| | - Jeroen Dubbeld
- Department of Surgery, Division of Transplantation, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Wouter H. J. Vaes
- The Netherlands Organisation for Applied Scientific Research (TNO), Zeist, The Netherlands
| | - Catherijne A. J. Knibbe
- Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre for Drug Research (LACDR), Leiden, The Netherlands
| | - Ian P. J. Alwayn
- Department of Surgery, Division of Transplantation, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Evita van de Steeg
- The Netherlands Organisation for Applied Scientific Research (TNO), Zeist, The Netherlands
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16
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Wang X, Liu Q, Zhong W, Yang L, Yang J, Covaci A, Zhu L. Estimating renal and hepatic clearance rates of organophosphate esters in humans: Impacts of intrinsic metabolism and binding affinity with plasma proteins. ENVIRONMENT INTERNATIONAL 2020; 134:105321. [PMID: 31783242 DOI: 10.1016/j.envint.2019.105321] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 10/29/2019] [Accepted: 11/11/2019] [Indexed: 05/25/2023]
Abstract
The renal and hepatic clearance rates of organophosphate esters (OPEs) in humans were estimated. Six OPEs and their corresponding diester metabolites (mOPEs) were quantified respectively in 30 paired human plasma and urine samples collected in Hengshui, Hebei province, China. The renal clearance rate (CLrenal) of triphenyl phosphate (TPHP), tris(chloroethyl) phosphate (TCEP) and tris(1,3-dichloro-isopropyl) phosphate (TDCIPP) was estimated to be 68.9, 50.9 and 33.3 mL/kg/day, respectively, while it was not calculated for other three OPEs due to the low detection frequencies in human samples. To estimate the clearance rates of the target OPEs, hepatic clearance rates (CLh) of OPEs were extrapolated from their in vitro intrinsic clearance data in human liver microsomes (CLHLM). The calculated CLh values of TCEP and TDCIPP were comparable to their CLrenal, indicating that the in vitro extrapolation method was suitable for estimating the clearance rates of OPEs. The higher binding affinity of TDCIPP with plasma proteins could reduce its renal clearance. The estimated half-lives of Cl-OPEs in human were longer than those of the aryl- and alkyl-OPEs. This study provided a feasible in vitro method to predict the clearance and half-lives of OPEs in human, which is significant for their accurate health risk assessment.
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Affiliation(s)
- Xiaolei Wang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Qing Liu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Wenjue Zhong
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Liping Yang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Jing Yang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Adrian Covaci
- Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China.
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17
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Food ingredient safety evaluation: Utility and relevance of toxicokinetic methods. Toxicol Appl Pharmacol 2019; 382:114759. [DOI: 10.1016/j.taap.2019.114759] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/06/2019] [Accepted: 09/11/2019] [Indexed: 11/22/2022]
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Abdallah MAE, Nguyen KH, Moehring T, Harrad S. First insight into human extrahepatic metabolism of flame retardants: Biotransformation of EH-TBB and Firemaster-550 components by human skin subcellular fractions. CHEMOSPHERE 2019; 227:1-8. [PMID: 30981098 DOI: 10.1016/j.chemosphere.2019.04.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and a mixture of EH-TBB, Bis(2-ethylhexyl)tetrabromphthalate (BEH-TEBP) and Triphenyl phosphate (TPhP), prepared in a ratio similar to the Firemaster-550™ (FM550) flame retardant formulation, were exposed to human skin subcellular fractions (S9) to evaluate their dermal in vitro metabolism for the first time. After 60 min of incubation, tetrabromobenzoic acid (TBBA) and diphenyl phosphate (DPhP) were identified as the major metabolites of EH-TBB and TPhP, respectively using UPLC-Q-Exactive Orbitrap™-MS analysis. Dermal biotransformation of EH-TBB and TPhP was catalyzed by skin carboxylesterases rather than CYP450 enzymes, while no stable metabolites could be identified for BEH-TEBP. Metabolite formation rates of EH-TBB as individual compound and as a component of FM550 fitted the Michaelis-Menten model, while no steady state could be reached for TPhP under experimental conditions. Estimated maximum metabolic rate (Vmax) for TBBA formation upon exposure to FM550 was lower than Vmax for EH-TBB (1.08 and 15.2 pmol min-1 mg protein-1, respectively). This indicates dermal metabolism would contribute less to the clearance of EH-TBB body burden than hepatic metabolism (Vmax = 644 pmol min-1 mg protein-1). Implications for human exposure include EH-TBB accumulation in skin tissue and human exposure to dermal metabolic products, which may have different toxicokinetic and toxicodynamic parameters than parent flame retardants.
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Affiliation(s)
- Mohamed Abou-Elwafa Abdallah
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B5 2TT, United Kingdom; Department of Analytical Chemistry, Faculty of Pharmacy, Assiut University, 71526, Assiut, Egypt.
| | - Khanh-Hoang Nguyen
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B5 2TT, United Kingdom
| | - Thomas Moehring
- Thermo Fisher Scientific (GmbH) Bremen, Hanna-Kunath-Str. 11, 28199, Bremen, Germany
| | - Stuart Harrad
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B5 2TT, United Kingdom
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Volarath P, Zang Y, Kabadi SV. Application of Computational Methods for the Safety Assessment of Food Ingredients. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/978-3-030-16443-0_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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20
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Schneider D, Oskamp A, Holschbach M, Neumaier B, Bauer A, Bier D. Relevance of In Vitro Metabolism Models to PET Radiotracer Development: Prediction of In Vivo Clearance in Rats from Microsomal Stability Data. Pharmaceuticals (Basel) 2019; 12:ph12020057. [PMID: 31013984 PMCID: PMC6631687 DOI: 10.3390/ph12020057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 04/10/2019] [Accepted: 04/12/2019] [Indexed: 01/03/2023] Open
Abstract
The prediction of in vivo clearance from in vitro metabolism models such as liver microsomes is an established procedure in drug discovery. The potentials and limitations of this approach have been extensively evaluated in the pharmaceutical sector; however, this is not the case for the field of positron emission tomography (PET) radiotracer development. The application of PET radiotracers and classical drugs differs greatly with regard to the amount of substance administered. In typical PET imaging sessions, subnanomolar quantities of the radiotracer are injected, resulting in body concentrations that cannot be readily simulated in analytical assays. This raises concerns regarding the predictability of radiotracer clearance from in vitro data. We assessed the accuracy of clearance prediction for three prototypical PET radiotracers developed for imaging the A1 adenosine receptor (A1AR). Using the half-life (t1/2) approach and physiologically based scaling, in vivo clearance in the rat model was predicted from microsomal stability data. Actual clearance could be accurately predicted with an average fold error (AFE) of 0.78 and a root mean square error (RMSE) of 1.6. The observed slight underprediction (1.3-fold) is in accordance with the prediction accuracy reported for classical drugs. This result indicates that the prediction of radiotracer clearance is possible despite concentration differences of more than three orders of magnitude between in vitro and in vivo conditions. Consequently, in vitro metabolism models represent a valuable tool for PET radiotracer development.
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Affiliation(s)
- Daniela Schneider
- Institute of Neuroscience and Medicine-Molecular Organization of the Brain (INM-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Angela Oskamp
- Institute of Neuroscience and Medicine-Molecular Organization of the Brain (INM-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Marcus Holschbach
- Institute of Neuroscience and Medicine-Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Bernd Neumaier
- Institute of Neuroscience and Medicine-Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Andreas Bauer
- Institute of Neuroscience and Medicine-Molecular Organization of the Brain (INM-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
- Neurological Department, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany.
| | - Dirk Bier
- Institute of Neuroscience and Medicine-Nuclear Chemistry (INM-5), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
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21
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Monostory K, Nagy A, Tóth K, Bűdi T, Kiss Á, Déri M, Csukly G. Relevance of CYP2C9 Function in Valproate Therapy. Curr Neuropharmacol 2019; 17:99-106. [PMID: 29119932 PMCID: PMC6341495 DOI: 10.2174/1570159x15666171109143654] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 10/09/2017] [Accepted: 11/07/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Genetic polymorphisms of drug metabolizing enzymes can substantially modify the pharmacokinetics of a drug and eventually its efficacy or toxicity; however, inferring a patient's drug metabolizing capacity merely from his or her genotype can lead to false prediction. Non-genetic host factors (age, sex, disease states) and environmental factors (nutrition, comedication) can transiently alter the enzyme expression and activities resulting in genotypephenotype mismatch. Although valproic acid is a well-tolerated anticonvulsant, pediatric patients are particularly vulnerable to valproate injury that can be partly attributed to the age-related differences in metabolic pathways. METHODS CYP2C9 mediated oxidation of valproate, which is the minor metabolic pathway in adults, appears to become the principal route in children. Genetic and non-genetic variations in CYP2C9 activity can result in significant inter- and intra-individual differences in valproate pharmacokinetics and valproate induced adverse reactions. RESULTS The loss-of-function alleles, CYP2C9*2 or CYP2C9*3, display significant reduction in valproate metabolism in children; furthermore, low CYP2C9 expression in patients with CYP2C9*1/*1 genotype also leads to a decrease in valproate metabolizing capacity. Due to phenoconversion, the homozygous wild genotype, expected to be translated to CYP2C9 enzyme with normal activity, is transiently switched into poor (or extensive) metabolizer phenotype. CONCLUSION Novel strategy for valproate therapy adjusted to CYP2C9-status (CYP2C9 genotype and CYP2C9 expression) is strongly recommended in childhood. The early knowledge of pediatric patients' CYP2C9-status facilitates the optimization of valproate dosing which contributes to the avoidance of misdosing induced adverse reactions, such as abnormal blood levels of ammonia and alkaline phosphatase, and improves the safety of children's anticonvulsant therapy.
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Affiliation(s)
- Katalin Monostory
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Andrea Nagy
- Heim Pal Children's Hospital, Budapest, Hungary
| | - Katalin Tóth
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás Bűdi
- 2nd Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Ádám Kiss
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Máté Déri
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gábor Csukly
- Department of Psychiatry and Psychotherapy, Semmelweis University, Budapest, Hungary
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Tohon H, Valcke M, Haddad S. An assessment of the impact of multi‐route co‐exposures on human variability in toxicokinetics: A case study with binary and quaternary mixtures of volatile drinking water contaminants. J Appl Toxicol 2019; 39:974-991. [DOI: 10.1002/jat.3787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/14/2018] [Accepted: 01/19/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Honesty Tohon
- Department of Environmental and Occupational Health, ESPUM, IRSPUMUniversité de Montréal Montreal QC Canada
| | - Mathieu Valcke
- Department of Environmental and Occupational Health, ESPUM, IRSPUMUniversité de Montréal Montreal QC Canada
- Institut national de santé publique du Québec Montréal QC Canada
| | - Sami Haddad
- Department of Environmental and Occupational Health, ESPUM, IRSPUMUniversité de Montréal Montreal QC Canada
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Kenyon EM, Lipscomb JC, Pegram RA, George BJ, Hines RN. The Impact of Scaling Factor Variability on Risk-Relevant Pharmacokinetic Outcomes in Children: A Case Study Using Bromodichloromethane (BDCM). Toxicol Sci 2019; 167:347-359. [PMID: 30252107 PMCID: PMC10448349 DOI: 10.1093/toxsci/kfy236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Biotransformation rates extrapolated from in vitro data are used increasingly in human physiologically based pharmacokinetic (PBPK) models. This practice requires use of scaling factors, including microsomal content (mg of microsomal protein/g liver, MPPGL), enzyme specific content, and liver mass as a fraction of body weight (FVL). Previous analyses indicated that scaling factor variability impacts pharmacokinetic (PK) outcomes used in adult population dose-response studies. This analysis was extended to pediatric populations because large inter-individual differences in enzyme ontogeny likely would further contribute to scaling factor variability. An adult bromodichloromethane (BDCM) model (Kenyon, E. M., Eklund, C., Leavens, T. L., and Pegram, R. A. (2016a). Development and application of a human PBPK model for bromodichloromethane (BDCM) to investigate impacts of multi-route exposure. J. Appl. Toxicol. 36, 1095-1111) was re-parameterized for neonates, infants, and toddlers. Monte Carlo analysis was used to assess the impact of pediatric scaling factor variation on model-derived PK outcomes compared with adult findings. BDCM dose metrics were estimated following a single 0.05-liter drink of water or a 20-min bath, under typical (5 µg/l) and plausible higher (20 µg/l) BDCM concentrations. MPPGL, CYP2E1, and FVL values reflected the distribution of reported pediatric population values. The impact of scaling factor variability on PK outcome variation was different for each exposure scenario, but similar for each BDCM water concentration. The higher CYP2E1 expression variability during early childhood was reflected in greater variability in predicted PK outcomes in younger age groups, particularly for the oral exposure route. Sensitivity analysis confirmed the most influential parameter for this variability was CYP2E1, particularly in neonates. These findings demonstrate the importance of age-dependent scaling factor variation used for in vitro to in vivo extrapolation of biotransformation rates.
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Tohon H, Nong A, Moreau M, Valcke M, Haddad S. Reverse dosimetry modeling of toluene exposure concentrations based on biomonitoring levels from the Canadian health measures survey. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2018; 81:1066-1082. [PMID: 30365389 DOI: 10.1080/15287394.2018.1534174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/05/2018] [Accepted: 10/06/2018] [Indexed: 06/08/2023]
Abstract
Biomonitoring might provide useful estimates of population exposure to environmental chemicals. However, data uncertainties stemming from interindividual variability are common in large population biomonitoring surveys. Physiologically based pharmacokinetic (PBPK) models might be used to account for age- and gender-related variability in internal dose. The objective of this study was to reconstruct air concentrations consistent with blood toluene measures reported in the third Canadian Health Measures Survey using reverse dosimetry PBPK modeling techniques. Population distributions of model's physiological parameters were described based upon age, weight, and size for four subpopulations (12-19, 20-39, 40-59, and 60-79 years old). Monte Carlo simulations applied to PBPK modeling allowed converting the distributions of venous blood measures of toluene obtained from CHMS into related air levels. Based upon blood levels observed at the 50th, 90th and 95th percentiles, corresponding air toluene concentrations were estimated for teenagers aged 12-19 years as being, respectively, 0.009, 0.04 and 0.06 ppm. Similarly, values were computed for adults aged 20-39 years (0.007, 0.036, and 0.06 ppm), 40-59 years (0.007, 0.036 and 0.06 ppm) and 60-79 years (0.006, 0.022 and 0.04 ppm). These estimations are well below Health Canada's maximum recommended chronic air guidelines for toluene. In conclusion, PBPK modeling and reverse dosimetry may be combined to help interpret biomonitoring data for chemical exposure in large population surveys and estimate the associated toxicological health risk.
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Affiliation(s)
- Honesty Tohon
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
| | - Andy Nong
- b Exposure and Biomonitoring Division , Environmental Health Sciences and Research Bureau, Health Canada , Ottawa , ON , Canada
| | - Marjory Moreau
- b Exposure and Biomonitoring Division , Environmental Health Sciences and Research Bureau, Health Canada , Ottawa , ON , Canada
| | - Mathieu Valcke
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
- c Direction de la santé environnementale et de la toxicologie , Institut national de santé publique du Québec , Montréal , Quebec , Canada
| | - Sami Haddad
- a Department of Environmental and Occupational Health , ESPUM, IRSPUM, Université de Montréal , Montreal , (Qc.) , Canada
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25
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Sultana N. Microbial biotransformation of bioactive and clinically useful steroids and some salient features of steroids and biotransformation. Steroids 2018; 136:76-92. [PMID: 29360535 DOI: 10.1016/j.steroids.2018.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 12/16/2017] [Accepted: 01/16/2018] [Indexed: 01/11/2023]
Abstract
Steroids are perhaps one of the most widely used group of drugs in present day. Beside the established utilization as immunosuppressive, anti-inflammatory, anti-rheumatic, progestational, diuretic, sedative, anabolic and contraceptive agents, recent applications of steroid compounds include the treatment of some forms of cancer, osteoporosis, HIV infections and treatment of declared AIDS. Steroids isolated are often available in minute amounts. So biotransformation of natural products provides a powerful means in solving supply problems in clinical trials and marketing of the drug for obtaining natural products in bulk amounts. If the structure is complex, it is often an impossible task to isolate enough of the natural products for clinical trials. The microbial biotransformation of steroids yielded several novel metabolites, exhibiting different activities. The metabolites produced from pregnenolone acetate by Cunning hamella elegans and Rhizopus stolonifer were screened against tyrosinase and cholinesterase showed significant inhibitory activities than the parent compound. Diosgenin and its transformed sarsasapogenin were screened for their acetyl cholinesterase and butyryl cholinesterase inhibitory activities. Sarsasapogenin was screened for phytotoxicity, and was found to be more active than the parent compound. Diosgenin, prednisone and their derivatives were screened for their anti-leishmanial activity. All derivatives were found to be more active than the parent compound. The biotransformation of steroids have been reviewed to a little extent. This review focuses on the biotransformation and functions of selected steroids, the classification, advantages and agents of enzymatic biotransformation and examines the potential role of new enzymatically transformed steroids and their derivatives in the chemoprevention and treatment of other diseases. tyrosinase and cholinesterase inhibitory activities, severe asthma, rheumatic disorders, renal disorders and diseases of inflammatory bowel, skin, gastrointestinal tract.
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Affiliation(s)
- Nighat Sultana
- Pharmaceutical Research Center, PCSIR Laboratories Complex, Shahrah-e-Dr. Salimuzzaman Siddiqui, Off University Road, Karachi 75280, Pakistan.
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26
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Li JN, Cao YF, He RR, Ge GB, Guo B, Wu JJ. Evidence for Shikonin acting as an active inhibitor of human carboxylesterases 2: Implications for herb-drug combination. Phytother Res 2018; 32:1311-1319. [PMID: 29468758 DOI: 10.1002/ptr.6062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 01/25/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Jia-Nan Li
- Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian 116023 China
- Department of Pharmacy; The First Affiliated Hospital of Jinzhou Medical University; Jinzhou 121001 China
| | - Yun-Feng Cao
- Key Laborotary of Liaoning Tumor Clinical Metabolomics; Jinzhou 121001 China
- RSKT Biopharma Inc.; Dalian 116023 China
| | - Rong-Rong He
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research; Guangzhou 510632 China
| | - Guang-Bo Ge
- Institute of Interdisciplinary Medicine; Shanghai University of Traditional Chinese Medicine; Shanghai 201203 China
| | - Bin Guo
- Department of Pharmacy; The First Affiliated Hospital of Jinzhou Medical University; Jinzhou 121001 China
| | - Jing-Jing Wu
- Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian 116023 China
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Zhan J, Liang Y, Liu D, Liu C, Liu H, Wang P, Zhou Z. Organochlorine pesticide acetofenate and its hydrolytic metabolite in rabbits: Enantioselective metabolism and cytotoxicity. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2018; 145:76-83. [PMID: 29482734 DOI: 10.1016/j.pestbp.2018.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 01/11/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
Acetofenate (AF) is a chiral organochlorine pesticide used for controlling hygiene pests. In this study, the metabolism of AF in rabbits in vivo and in vitro was investigated and the primary chiral metabolite acetofenate-alcohol (AF-A) was analyzed. The cytotoxicity of AF and AF-A was also determined. AF in rabbits in vivo was eliminated so rapidly that AF could not be detected within 10min after intravenous administration at 20mg/kg (body weight), and AF-A was quickly formed. In vitro metabolism assay, using plasma and liver microsomes, showed that AF was also quickly metabolized to AF-A and the metabolic process was significantly enantioselective with preferential degradation of (-)-AF and formation of (-)-AF-A. The cytotoxicity of AF and AF-A were investigated by assessing cell proliferation, apoptosis and generation of reactive oxygen species. The results showed that AF and AF-A induce enantioselective cytotoxicity. This study will be helpful for improving knowledge about the metabolism and toxicity of AF on an enantiomeric level and providing evidence to understand the potential environmental risk.
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Affiliation(s)
- Jing Zhan
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Yiran Liang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Donghui Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Chang Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Hui Liu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Peng Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Science, Agricultural University, Beijing 100193, China.
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Calitz C, Hamman JH, Fey SJ, Wrzesinski K, Gouws C. Recent advances in three-dimensional cell culturing to assess liver function and dysfunction: from a drug biotransformation and toxicity perspective. Toxicol Mech Methods 2018; 28:369-385. [PMID: 29297242 DOI: 10.1080/15376516.2017.1422580] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Carlemi Calitz
- Pharmacen™, Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | - Josias H. Hamman
- Pharmacen™, Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
| | - Stephen J. Fey
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Krzysztof Wrzesinski
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Chrisna Gouws
- Pharmacen™, Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa
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29
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Tóth K, Sirok D, Kiss Á, Mayer A, Pátfalusi M, Hirka G, Monostory K. Utility of in vitro clearance in primary hepatocyte model for prediction of in vivo hepatic clearance of psychopharmacons. Microchem J 2018. [DOI: 10.1016/j.microc.2016.10.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Nguyen KH, Abou-Elwafa Abdallah M, Moehring T, Harrad S. Biotransformation of the Flame Retardant 1,2-Dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) in Vitro by Human Liver Microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10511-10518. [PMID: 28846412 DOI: 10.1021/acs.est.7b02834] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The technical mixture of 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH or DBE-DBCH) and the pure β-TBECH isomer were subjected to in vitro biotransformation by human liver microsomes (HLM). After 60 min of incubation, 5 potential metabolites of TBECH were identified in microsomal assays of both the TBECH mixture and β-TBECH using ultraperformance liquid chromatography-Q-Exactive Orbitrap mass spectrometry. These include mono- and dihydroxylated TBECH and mono- and dihydroxylated TriBECH as well as an α-oxidation metabolite bromo-(1,2-dibromocyclohexyl)-acetic acid. Our results indicate potential hepatic biotransformation of TBECH via cyctochrome P450-catalyzed hydroxylation, debromination, and α-oxidation. Kinetic studies revealed that the formation of monohydroxy-TBECH, dihydroxy-TBECH, and monohydroxy-TriBECH were best fitted to a Michaelis-Menten enzyme kinetic model. Respective estimated Vmax values (maximum metabolic rate) for these metabolites were 11.8 ± 4, 0.6 ± 0.1, and 10.1 ± 0.8 pmol min-1 mg protein-1 in TBECH mixture and 4992 ± 1340, 14.1 ± 4.9, and 66.1 ± 7.3 pmol min-1 mg protein-1 in β-TBECH. This indicates monohydroxy-TBECH as the major metabolite of TBECH by in vitro HLM-based assay. The estimated in vitro intrinsic clearance (Clint) of TBECH mixture was slower (P < 0.05) than that of pure β-TBECH. While the formation of monohydroxy-TBECH may reduce the bioaccumulation potential and provide a useful biomarker for monitoring TBECH exposure, further studies are required to fully understand the levels and toxicological implications of the identified metabolites.
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Affiliation(s)
- Khanh-Hoang Nguyen
- School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham, B5 2TT United Kingdom
| | - Mohamed Abou-Elwafa Abdallah
- School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham, B5 2TT United Kingdom
- Department of Analytical Chemistry, Faculty of Pharmacy, Assiut University , 71526 Assiut, Egypt
| | - Thomas Moehring
- Thermo Fisher Scientific (GmbH) Bremen , Hanna-Kunath-Strasse 11, 28199 Bremen, Germany
| | - Stuart Harrad
- School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham, B5 2TT United Kingdom
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31
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Kenyon EM, Eklund C, Lipscomb JC, Pegram RA. The impact of variation in scaling factors on the estimation of internal dose metrics: a case study using bromodichloromethane (BDCM). Toxicol Mech Methods 2016; 26:620-626. [DOI: 10.1080/15376516.2016.1225141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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32
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Yao Z, Qian M, Zhang H, Nie J, Ye J, Li Z. Etoxazole is Metabolized Enantioselectively in Liver Microsomes of Rat and Human in Vitro. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9682-9688. [PMID: 27479246 DOI: 10.1021/acs.est.6b02676] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Acaricide etoxazole belongs to the ovicides/miticides diphenyloxazole class, affecting adults to lay sterile eggs by inhibiting chitin biosynthesis possibly. The reverse-phase HPLC-MS/MS method was used to determine the etoxazole enantiomers. The enantioselective degradation behavior of rac-etoxazole in liver microsomes of rat and human in vitro with NADPH was dramatically different. The t1/2 of (R)-etoxazole was 15.23 min in rat liver microsomes and 30.54 min in human liver microsomes, while 21.73 and 23.50 min were obtained for (S)-etoxazole, respectively. The Vmax of (R)-etoxazole was almost 5-fold of (S)-etoxazole in liver microsomes of rat in vitro. However, the Vmax of (S)-etoxazole was almost 2-fold of (R)-etoxazole in liver microsomes of human in vitro. The CLint of etoxazole was also shown the enantioselectivity on the contrary in liver microsomes of rat and human. These results indicated that the metabolism of two etoxazole enantiomers was selective in liver microsomes of rat and human in vitro, and enantioselectivity in the two kinds of liver microsomes was in the difference in degradation performance. The reason might be related to the composition and content involved in the enzyme system.
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Affiliation(s)
- Zhoulin Yao
- College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China
- Zhejiang Citrus Research Institute, Zhejiang Academy of Agricultural Sciences , Taizhou 318020, China
- Institute of Quality and Standard for Agricultural Products, Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang Province, State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, and MOA Key Laboratory for Pesticide Residue Detection, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
| | - Mingrong Qian
- Institute of Quality and Standard for Agricultural Products, Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang Province, State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, and MOA Key Laboratory for Pesticide Residue Detection, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
| | - Hu Zhang
- Institute of Quality and Standard for Agricultural Products, Key Laboratory of Detection for Pesticide Residues and Control of Zhejiang Province, State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, and MOA Key Laboratory for Pesticide Residue Detection, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
| | - Jing Nie
- College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China
| | - Jingqing Ye
- College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China
| | - Zuguang Li
- College of Chemical Engineering, Zhejiang University of Technology , Hangzhou 310014, China
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33
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Parmentier Y, Pothier C, Delmas A, Caradec F, Trancart MM, Guillet F, Bouaita B, Chesne C, Brian Houston J, Walther B. Direct and quantitative evaluation of the human CYP3A4 contribution (fm) to drug clearance using the in vitro SILENSOMES model. Xenobiotica 2016; 47:562-575. [DOI: 10.1080/00498254.2016.1208854] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yannick Parmentier
- Biopharmaceutical Research Department, Technologie Servier, Orléans Cedex, France,
| | - Corinne Pothier
- Biopharmaceutical Research Department, Technologie Servier, Orléans Cedex, France,
| | - Audrey Delmas
- Biopharmaceutical Research Department, Technologie Servier, Orléans Cedex, France,
| | - Fabrice Caradec
- Biopharmaceutical Research Department, Technologie Servier, Orléans Cedex, France,
| | | | | | | | | | | | - Bernard Walther
- Biopharmaceutical Research Department, Technologie Servier, Orléans Cedex, France,
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Abstract
The exponential growth of the Internet of Things and the global popularity and remarkable decline in cost of the mobile phone is driving the digital transformation of medical practice. The rapidly maturing digital, non-medical world of mobile (wireless) devices, cloud computing and social networking is coalescing with the emerging digital medical world of omics data, biosensors and advanced imaging which offers the increasingly realistic prospect of personalized medicine. Described as a potential “seismic” shift from the current “healthcare” model to a “wellness” paradigm that is predictive, preventative, personalized and participatory, this change is based on the development of increasingly sophisticated biosensors which can track and measure key biochemical variables in people. Additional key drivers in this shift are metabolomic and proteomic signatures, which are increasingly being reported as pre-symptomatic, diagnostic and prognostic of toxicity and disease. These advancements also have profound implications for toxicological evaluation and safety assessment of pharmaceuticals and environmental chemicals. An approach based primarily on human in vivo and high-throughput in vitro human cell-line data is a distinct possibility. This would transform current chemical safety assessment practice which operates in a human “data poor” to a human “data rich” environment. This could also lead to a seismic shift from the current animal-based to an animal-free chemical safety assessment paradigm.
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Affiliation(s)
- George D Loizou
- Health Risks, Health and Safety Laboratory, Health and Safety Executive Buxton, UK
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35
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Lv X, Wang XX, Hou J, Fang ZZ, Wu JJ, Cao YF, Liu SW, Ge GB, Yang L. Comparison of the inhibitory effects of tolcapone and entacapone against human UDP-glucuronosyltransferases. Toxicol Appl Pharmacol 2016; 301:42-9. [PMID: 27089846 DOI: 10.1016/j.taap.2016.04.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 01/15/2023]
Abstract
Tolcapone and entacapone are two potent catechol-O-methyltransferase (COMT) inhibitors with a similar skeleton and displaying similar pharmacological activities. However, entacapone is a very safe drug used widely in the treatment of Parkinson's disease, while tolcapone is only in limited use for Parkinson's patients and needs careful monitoring of hepatic functions due to hepatotoxicity. This study aims to investigate and compare the inhibitory effects of entacapone and tolcapone on human UDP-glucosyltransferases (UGTs), as well as to evaluate the potential risks from the view of drug-drug interactions (DDI). The results demonstrated that both tolcapone and entacapone exhibited inhibitory effects on UGT1A1, UGT1A7, UGT1A9 and UGT1A10. In contrast to entacapone, tolcapone exhibited more potent inhibitory effects on UGT1A1, UGT1A7, and UGT1A10, while their inhibitory potentials against UGT1A9 were comparable. It is noteworthy that the inhibition constants (Ki) of tolcapone and entacapone against bilirubin-O-glucuronidation in human liver microsomes (HLM) are determined as 0.68μM and 30.82μM, respectively, which means that the inhibition potency of tolcapone on UGT1A1 mediated bilirubin-O-glucuronidation in HLM is much higher than that of entacapone. Furthermore, the potential risks of tolcapone or entacapone via inhibition of human UGT1A1 were quantitatively predicted by the ratio of the areas under the plasma drug concentration-time curve (AUC). The results indicate that tolcapone may result in significant increase in AUC of bilirubin or the drugs primarily metabolized by UGT1A1, while entacapone is unlikely to cause a significant DDI through inhibition of UGT1A1.
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Affiliation(s)
- Xia Lv
- Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515, China
| | | | - Jie Hou
- Dalian Medical University, Dalian 116044, China
| | | | - Jing-Jing Wu
- Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515, China
| | | | - Shu-Wen Liu
- State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515, China
| | - Guang-Bo Ge
- Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515, China.
| | - Ling Yang
- Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; Jiangxi University of Traditional Chinese Medicine, Nanchang 330006, China.
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Lin C, Miao Y, Qian M, Wang Q, Zhang H. Enantioselective Metabolism of Flufiprole in Rat and Human Liver Microsomes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:2371-2376. [PMID: 26938045 DOI: 10.1021/acs.jafc.5b05853] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The enantioselective metabolism of flufiprole in rat and human liver microsomes in vitro was investigated in this study. The separation and determination were performed using a liquid chromatography system equipped with a triple-quadrupole mass spectrometer and a Lux Cellulose-2 chiral column. The enantioselective metabolism of rac-flufiprole was dramatically different in rat and human liver microsomes in the presence of the β-nicotinamide adenine dinucleotide phosphate regenerating system. The half-lives (t1/2) of flufiprole in rat and human liver microsomes were 7.22 and 21.00 min, respectively, for R-(+)-flufiprole, whereas the values were 11.75 and 17.75 min, respectively, for S-(-)-flufiprole. In addition, the Vmax of R-(+)-flufiprole was about 3-fold that of S-(-)-flufiprole in rat liver microsomes, whereas its value in the case of S-(-)-flufiprole was about 2-fold that of R-(+)-flufiprole in human liver microsomes. The CLint of rac-flufiprole also showed opposite enantioselectivy in rat and human liver microsomes. The different compositions and contents of metabolizing enzyme in the two liver microsomes might be the reasons for the difference in the metabolic behavior of the two enantiomers.
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Affiliation(s)
- Chunmian Lin
- College of Biological and Environmental Engineering, Zhejiang University of Technology , Hangzhou 310014, China
| | - Yelong Miao
- College of Biological and Environmental Engineering, Zhejiang University of Technology , Hangzhou 310014, China
| | - Mingrong Qian
- Institute of Quality and Standard for Agricultural Products, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
| | - Qiang Wang
- Institute of Quality and Standard for Agricultural Products, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
| | - Hu Zhang
- Institute of Quality and Standard for Agricultural Products, Zhejiang Academy of Agricultural Sciences , Hangzhou 310021, China
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37
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Pirovano A, Brandmaier S, Huijbregts MAJ, Ragas AMJ, Veltman K, Hendriks AJ. QSARs for estimating intrinsic hepatic clearance of organic chemicals in humans. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 42:190-197. [PMID: 26874337 DOI: 10.1016/j.etap.2016.01.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 06/05/2023]
Abstract
Quantitative structure-activity relationships (QSARs) were developed to predict the in vitro clearance (CLINT) of xenobiotics metabolised in human hepatocytes (118 compounds) and microsomes (115 compounds). Clearance values were gathered from the scientific literature and multiple linear models were built and validated selecting at most 6 predictors from a pool of over 2000 potential molecular descriptors. For the hepatocytes QSAR, the explained variance (Radj(2)) was 67% and the predictive ability (Rext(2)) was 62%. For the microsomes QSAR, Radj(2) was 50% and Rext(2) 30%. For both liver assays, the most important descriptor relates to electronic properties of the compound. Functional groups of fragments were useful to identify specific compounds that have a deviating reaction rate compared to the others, such as polychlorobiphenyls (PCBs) and organic amides which were poorly metabolised by hepatocytes and microsomes, respectively. For hepatocytes, clearance was predominantly determined by electronic characteristics, while size and shape characteristics were less important and partitioning properties were absent. This may suggest that uptake across the membrane and enzyme binding are not rate-limiting steps. Particularly for hepatocytes the QSAR statistics are encouraging, allowing application of the outcomes in in vitro to in vivo extrapolation.
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Affiliation(s)
- Alessandra Pirovano
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Stefan Brandmaier
- Helmholtz-Zentrum München - German Research Centre for Environmental Health (GmbH), Research Unit of Molecular Epidemiology, Institute of Epidemiology II, Munich, Germany
| | - Mark A J Huijbregts
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad M J Ragas
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands; Faculty of Management, Science and Technology, Open University, Heerlen, The Netherlands
| | - Karin Veltman
- University of Michigan, School of Public Health, Department of Environmental Health Sciences, 1415 Washington Heights, Ann Arbor, MI, USA
| | - A Jan Hendriks
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Terry C, Hays S, McCoy AT, McFadden LG, Aggarwal M, Rasoulpour RJ, Juberg DR. Implementing a framework for integrating toxicokinetics into human health risk assessment for agrochemicals. Regul Toxicol Pharmacol 2016; 75:89-104. [DOI: 10.1016/j.yrtph.2015.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 10/01/2015] [Accepted: 10/04/2015] [Indexed: 01/25/2023]
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Van den Eede N, de Meester I, Maho W, Neels H, Covaci A. Biotransformation of three phosphate flame retardants and plasticizers in primary human hepatocytes: untargeted metabolite screening and quantitative assessment. J Appl Toxicol 2016; 36:1401-8. [DOI: 10.1002/jat.3293] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 12/12/2015] [Accepted: 12/22/2015] [Indexed: 01/14/2023]
Affiliation(s)
- Nele Van den Eede
- Toxicological Center, Department of Pharmaceutical Sciences; University of Antwerp; Universiteitsplein 1 2610 Antwerp Belgium
| | - Ingrid de Meester
- Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences; University of Antwerp; Universiteitsplein 1 2610 Antwerp Belgium
| | - Walid Maho
- Toxicological Center, Department of Pharmaceutical Sciences; University of Antwerp; Universiteitsplein 1 2610 Antwerp Belgium
| | - Hugo Neels
- Toxicological Center, Department of Pharmaceutical Sciences; University of Antwerp; Universiteitsplein 1 2610 Antwerp Belgium
| | - Adrian Covaci
- Toxicological Center, Department of Pharmaceutical Sciences; University of Antwerp; Universiteitsplein 1 2610 Antwerp Belgium
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Van den Eede N, Tomy G, Tao F, Halldorson T, Harrad S, Neels H, Covaci A. Kinetics of tris (1-chloro-2-propyl) phosphate (TCIPP) metabolism in human liver microsomes and serum. CHEMOSPHERE 2016; 144:1299-1305. [PMID: 26473552 DOI: 10.1016/j.chemosphere.2015.09.049] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/08/2015] [Accepted: 09/11/2015] [Indexed: 06/05/2023]
Abstract
Tris(1-chloro-2-propyl) phosphate (TCIPP) is an emerging contaminant which is ubiquitous in the indoor and outdoor environment. Moreover, its presence in human body fluids and biota has been evidenced. Since no quantitative data exist on the biotransformation or stability of TCIPP in the human body, we performed an in vitro incubation of TCIPP with human liver microsomes (HLM) and human serum (HS). Two metabolites, namely bis(2-chloro-isopropyl) phosphate (BCIPP) and bis(1-chloro-2-propyl) 1-hydroxy-2-propyl phosphate (BCIPHIPP), were quantified in a kinetic study using HLM or HS (only BCIPP, the hydrolysis product) and LC-MS. The Michaelis-Menten model fitted best the NADPH-dependent formation of BCIPHIPP and BCIPP in HLM, with respective V(MAX) of 154 ± 4 and 1470 ± 110 pmol/min/mg protein and respective apparent K(m) of 80.2 ± 4.4 and 96.1 ± 14.5 μM. Hydrolases, which are naturally present in HLM, were also involved in the production of BCIPP. A HS paraoxonase assay could not detect any BCIPP formation above 38.6 ± 10.8 pmol/min/μL serum. Our data indicate that BCIPP is the major metabolite of TCIPP formed in the liver. To our knowledge, this is the first quantitative assessment of the stability of TCIPP in tissues of humans or any other species. Further research is needed to confirm whether these biotransformation reactions are associated with a decrease or increase in toxicity.
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Affiliation(s)
- Nele Van den Eede
- Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium.
| | - Gregg Tomy
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Fang Tao
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Thor Halldorson
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Stuart Harrad
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Hugo Neels
- Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium
| | - Adrian Covaci
- Toxicological Center, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium.
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41
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Kenyon EM, Eklund C, Leavens T, Pegram RA. Development and application of a human PBPK model for bromodichloromethane to investigate the impacts of multi-route exposure. J Appl Toxicol 2015; 36:1095-111. [PMID: 26649444 DOI: 10.1002/jat.3269] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/05/2015] [Accepted: 10/26/2015] [Indexed: 12/25/2022]
Abstract
As a result of its presence in water as a volatile disinfection byproduct, bromodichloromethane (BDCM), which is mutagenic, poses a potential health risk from exposure via oral, dermal and inhalation routes. We developed a refined human physiologically based pharmacokinetic (PBPK) model for BDCM (including new chemical-specific human parameters) to evaluate the impact of BDCM exposure during showering and bathing on important measures of internal dose compared with oral exposure. The refined model adequately predicted data from the published literature for oral, dermal and bathing/showering exposures. A liter equivalency approach (L-eq) was used to estimate BDCM concentration in a liter of water consumed by the oral route that would be required to produce the same internal dose of BDCM resulting from a 20-min bath or a 10-min shower in water containing 10 µg l(-1) BDCM. The oral liter equivalent concentrations for the bathing scenario were 605, 803 and 5 µg l(-1) BDCM for maximum venous blood concentration (Cmax), the area under the curve (AUCv) and the amount metabolized in the liver per hour (MBDCM), respectively. For a 10-min showering exposure, the oral L-eq concentrations were 282, 312 and 2.1 µg l(-1) for Cmax, AUC and MBDCM, respectively. These results demonstrate large contributions of dermal and inhalation exposure routes to the internal dose of parent chemical reaching the systemic circulation, which could be transformed to mutagenic metabolites in extrahepatic target tissues. Thus, consideration of the contribution of multiple routes of exposure when evaluating risks from water-borne BDCM is needed, and this refined human model will facilitate improved assessment of internal doses from real-world exposures. Published 2015. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Elaina M Kenyon
- Integrated Systems Toxicology Division, U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
| | - Christopher Eklund
- Integrated Systems Toxicology Division, U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
| | | | - Rex A Pegram
- Integrated Systems Toxicology Division, U.S. EPA, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Research Triangle Park, NC, USA
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Sweeney LM, Goodwin MR, Hulgan AD, Gut CP, Bannon DI. Toxicokinetic Model Development for the Insensitive Munitions Component 2,4-Dinitroanisole. Int J Toxicol 2015; 34:417-32. [PMID: 26173616 DOI: 10.1177/1091581815594623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Armed Forces are developing new explosives that are less susceptible to unintentional detonation (insensitive munitions [IMX]). 2,4-Dinitroanisole (DNAN) is a component of IMX. Toxicokinetic data for DNAN are required to support interpretation of toxicology studies and refinement of dose estimates for human risk assessment. Male Sprague-Dawley rats were dosed by gavage (5, 20, or 80 mg DNAN/kg), and blood and tissue samples were analyzed to determine the levels of DNAN and its metabolite 2,4-dinitrophenol (DNP). These data and data from the literature were used to develop preliminary physiologically based pharmacokinetic (PBPK) models. The model simulations indicated saturable metabolism of DNAN in rats at higher tested doses. The PBPK model was extrapolated to estimate the toxicokinetics of DNAN and DNP in humans, allowing the estimation of human-equivalent no-effect levels of DNAN exposure from no-observed adverse effect levels determined in laboratory animals, which may guide the selection of exposure limits for DNAN.
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Affiliation(s)
- Lisa M Sweeney
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Naval Medical Research Unit Dayton (NAMRUD), Wright Patterson Air Force Base, OH, USA
| | | | - Angela D Hulgan
- Oak Ridge Institute for Science and Education, NAMRUD, Wright Patterson Air Force Base, OH, USA
| | - Chester P Gut
- CAMRIS, NAMRUD, Wright Patterson Air Force Base, OH, USA
| | - Desmond I Bannon
- US Army Public Health Command, Institute of Public Health, Toxicology Portfolio, Aberdeen Proving Ground, MD, USA
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Loizou GD, McNally K, Jones K, Cocker J. The application of global sensitivity analysis in the development of a physiologically based pharmacokinetic model for m-xylene and ethanol co-exposure in humans. Front Pharmacol 2015; 6:135. [PMID: 26175688 PMCID: PMC4485162 DOI: 10.3389/fphar.2015.00135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/17/2015] [Indexed: 11/13/2022] Open
Abstract
Global sensitivity analysis (SA) was used during the development phase of a binary chemical physiologically based pharmacokinetic (PBPK) model used for the analysis of m-xylene and ethanol co-exposure in humans. SA was used to identify those parameters which had the most significant impact on variability of venous blood and exhaled m-xylene and urinary excretion of the major metabolite of m-xylene metabolism, 3-methyl hippuric acid. This analysis informed the selection of parameters for estimation/calibration by fitting to measured biological monitoring (BM) data in a Bayesian framework using Markov chain Monte Carlo (MCMC) simulation. Data generated in controlled human studies were shown to be useful for investigating the structure and quantitative outputs of PBPK models as well as the biological plausibility and variability of parameters for which measured values were not available. This approach ensured that a priori knowledge in the form of prior distributions was ascribed only to those parameters that were identified as having the greatest impact on variability. This is an efficient approach which helps reduce computational cost.
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Affiliation(s)
- George D Loizou
- Computational Toxicology Team, Mathematical Sciences Unit, Health and Safety Laboratory Buxton, UK
| | - Kevin McNally
- Computational Toxicology Team, Mathematical Sciences Unit, Health and Safety Laboratory Buxton, UK
| | - Kate Jones
- Computational Toxicology Team, Mathematical Sciences Unit, Health and Safety Laboratory Buxton, UK
| | - John Cocker
- Computational Toxicology Team, Mathematical Sciences Unit, Health and Safety Laboratory Buxton, UK
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Willemin ME, Kadar A, de Sousa G, Leclerc E, Rahmani R, Brochot C. In vitro human metabolism of permethrin isomers alone or as a mixture and the formation of the major metabolites in cryopreserved primary hepatocytes. Toxicol In Vitro 2015; 29:803-12. [DOI: 10.1016/j.tiv.2015.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/29/2015] [Accepted: 03/01/2015] [Indexed: 11/24/2022]
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Van den Eede N, Erratico C, Exarchou V, Maho W, Neels H, Covaci A. In vitro biotransformation of tris(2-butoxyethyl) phosphate (TBOEP) in human liver and serum. Toxicol Appl Pharmacol 2015; 284:246-53. [PMID: 25681655 DOI: 10.1016/j.taap.2015.01.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/26/2015] [Accepted: 01/29/2015] [Indexed: 10/24/2022]
Abstract
Tris(2-butoxyethyl) phosphate (TBOEP) is a plasticizer present in indoor dust, reaching levels of several micrograms per gram. Such levels could lead to significant daily exposure of adults and children. Currently, no toxicokinetic data are available to estimate TBOEP clearance in humans after uptake and therefore, one objective of this study was to investigate intrinsic clearance of TBOEP by human liver microsome (HLM) and serum enzymes. Another objective was to generate information to identify and prioritize several metabolites of TBOEP for investigation of human exposure by biomonitoring. 1D and 2D-NMR methodologies were successfully applied on a mixture of the metabolites to confirm the structure of 3-HO-TBOEP (bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate) and to tentatively assign structures to 1-HO-TBOEP and 2-HO-TBOEP. HO-TBOEP isomers and bis(2-butoxyethyl) phosphate (BBOEP), bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) were further monitored by liquid chromatography-tandem mass spectrometry. Rates of formation of BBOEHEP and HO-TBOEP metabolites by liver enzymes were best described by the Michaelis-Menten model. Apparent Km values for BBOEHEP, 3-HO-TBOEP, and sum of 1- and 2-HO-TBOEP isomer formation were 152, 197 and 148μM, respectively. Apparent Vmax values for the formation of BBOEHEP, 3-HO-TBOEP, and the sum of 1- and 2-HO-TBOEP isomers were 2560, 643, and 254pmol/min/mg protein, respectively. No detectable formation of BBOEP occurred with liver or serum enzymes. Our findings indicate that intrinsic clearance of TBOEP is mainly catalyzed by oxidative enzymes in the liver and that its major in vitro metabolite is BBOEHEP. These findings can be applied in human biomonitoring studies and risk assessment.
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Affiliation(s)
- Nele Van den Eede
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
| | - Claudio Erratico
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Vassiliki Exarchou
- Natural Products & Food Research and Analysis (NatuRA), Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Walid Maho
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Hugo Neels
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Adrian Covaci
- Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
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46
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Pirovano A, Brandmaier S, Huijbregts MAJ, Ragas AMJ, Veltman K, Hendriks AJ. The utilisation of structural descriptors to predict metabolic constants of xenobiotics in mammals. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 39:247-258. [PMID: 25531263 DOI: 10.1016/j.etap.2014.11.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 11/28/2014] [Accepted: 11/29/2014] [Indexed: 06/04/2023]
Abstract
Quantitative structure-activity relationships (QSARs) were developed to predict the Michaelis-Menten constant (Km) and the maximum reaction rate (Vmax) of xenobiotics metabolised by four enzyme classes in mammalian livers: alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), flavin-containing monooxygenase (FMO), and cytochrome P450 (CYP). Metabolic constants were gathered from the literature and a genetic algorithm was employed to select at most six predictors from a pool of over 2000 potential molecular descriptors using two-thirds of the xenobiotics in each enzyme class. The resulting multiple linear models were cross-validated using the remaining one-third of the compounds. The explained variances (R(2)adj) of the QSARs were between 50% and 80% and the predictive abilities (R(2)ext) between 50% and 60%, except for the Vmax QSAR of FMO with both R(2)adj and R(2)ext less than 30%. The Vmax values of FMO were independent of substrate chemical structure because the rate-limiting step of its catalytic cycle occurs before compound oxidation. For the other enzymes, Vmax was predominantly determined by functional groups or fragments and electronic properties because of the strong and chemical-specific interactions involved in the metabolic reactions. The most relevant predictors for Km were functional groups or fragments for the enzymes metabolising specific compounds (ADH, ALDH and FMO) and size and shape properties for CYP, likely because of the broad substrate specificity of CYP enzymes. The present study can be helpful to predict the Km and Vmax of four important oxidising enzymes in mammals and better understand the underlying principles of chemical transformation by liver enzymes.
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Affiliation(s)
- Alessandra Pirovano
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Stefan Brandmaier
- Helmholtz Zentrum München-German Research Centre for Environmental Health (GmbH), Institute of Structural Biology, Ingolstaedter Landstrasse 1, Neuherberg, D-85764 Munich, Germany; Helmholtz-Zentrum München-German Research Centre for Environmental Health (GmbH), Research Unit of Molecular Epidemiology, Institute of Epidemiology II, Munich, Germany
| | - Mark A J Huijbregts
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad M J Ragas
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands; Faculty of Management, Science and Technology, Open University, Heerlen, The Netherlands
| | - Karin Veltman
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - A Jan Hendriks
- Radboud University Nijmegen, Institute for Wetland and Water Research, Department of Environmental Science, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Valcke M, Haddad S. Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2015; 78:409-431. [PMID: 25785556 DOI: 10.1080/15287394.2014.971477] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered.
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Affiliation(s)
- Mathieu Valcke
- a Institut national de santé publique du Québec , Montréal , Quebec , Canada
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48
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Wetmore BA, Allen B, Clewell HJ, Parker T, Wambaugh JF, Almond LM, Sochaski MA, Thomas RS. Incorporating population variability and susceptible subpopulations into dosimetry for high-throughput toxicity testing. Toxicol Sci 2014; 142:210-24. [PMID: 25145659 DOI: 10.1093/toxsci/kfu169] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Momentum is growing worldwide to use in vitro high-throughput screening (HTS) to evaluate human health effects of chemicals. However, the integration of dosimetry into HTS assays and incorporation of population variability will be essential before its application in a risk assessment context. Previously, we employed in vitro hepatic metabolic clearance and plasma protein binding data with in vitro in vivo extrapolation (IVIVE) modeling to estimate oral equivalent doses, or daily oral chemical doses required to achieve steady-state blood concentrations (Css) equivalent to media concentrations having a defined effect in an in vitro HTS assay. In this study, hepatic clearance rates of selected ToxCast chemicals were measured in vitro for 13 cytochrome P450 and five uridine 5'-diphospho-glucuronysyltransferase isozymes using recombinantly expressed enzymes. The isozyme-specific clearance rates were then incorporated into an IVIVE model that captures known differences in isozyme expression across several life stages and ethnic populations. Comparison of the median Css for a healthy population against the median or the upper 95th percentile for more sensitive populations revealed differences of 1.3- to 4.3-fold or 3.1- to 13.1-fold, respectively. Such values may be used to derive chemical-specific human toxicokinetic adjustment factors. The IVIVE model was also used to estimate subpopulation-specific oral equivalent doses that were directly compared with subpopulation-specific exposure estimates. This study successfully combines isozyme and physiologic differences to quantitate subpopulation pharmacokinetic variability. Incorporation of these values with dosimetry and in vitro bioactivities provides a viable approach that could be employed within a high-throughput risk assessment framework.
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Affiliation(s)
- Barbara A Wetmore
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Brittany Allen
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Harvey J Clewell
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Timothy Parker
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - John F Wambaugh
- United States Environmental Protection Agency, Office of Research and Development, National Center for Computational Toxicology, Research Triangle Park, North Carolina 27711
| | - Lisa M Almond
- Simcyp Limited (a Certara company), Blades Enterprise Centre, John Street, Sheffield S2 4SU, UK
| | - Mark A Sochaski
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Russell S Thomas
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
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49
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A human life-stage physiologically based pharmacokinetic and pharmacodynamic model for chlorpyrifos: Development and validation. Regul Toxicol Pharmacol 2014; 69:580-97. [DOI: 10.1016/j.yrtph.2013.10.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 10/18/2013] [Accepted: 10/19/2013] [Indexed: 12/25/2022]
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50
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Yoon M, Kedderis GL, Yan GZ, Clewell HJ. Use of in vitro data in developing a physiologically based pharmacokinetic model: Carbaryl as a case study. Toxicology 2014; 332:52-66. [PMID: 24863738 DOI: 10.1016/j.tox.2014.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 04/02/2014] [Accepted: 05/18/2014] [Indexed: 12/14/2022]
Abstract
In vitro-derived information has been increasingly used to support and improve human health risk assessment for exposure to chemicals. Physiologically based pharmacokinetic (PBPK) modeling is a key component in the movement toward in vitro-based risk assessment, providing a tool to integrate diverse experimental data and mechanistic information to relate in vitro effective concentrations to equivalent human exposures. One of the challenges, however, in the use of PBPK models for this purpose has been the need for extensive chemical-specific parameters. With the remarkable advances in in vitro methodologies in recent years, in vitro-derived parameters can now be easily incorporated into PBPK models. In this study we demonstrate an in vitro data based parameterization approach to develop a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model, using carbaryl as a case study. In vitro experiments were performed to provide the chemical-specific pharmacokinetic (PK) and pharmacodynamic (PD) parameters for carbaryl in the PBPK model for this compound. Metabolic clearance and cholinesterase (ChE) interaction parameters for carbaryl were measured in rat and human tissues. These in vitro PK and PD data were extrapolated to parameters in the whole body PBPK model using biologically appropriate scaling. The PBPK model was then used to predict the kinetics and ChE inhibition dynamics of carbaryl in vivo. This case study with carbaryl provides a reasonably successful example of utilizing the in vitro to in vivo extrapolation (IVIVE) approach for PBPK model development. This approach can be applied to other carbamates with an anticholinesterase mode of action as well as to environmental chemicals in general with further refinement of the current shortcomings in the approach. It will contribute to minimizing the need for in vivo human data for PBPK model parameterization and evaluation in human risk assessments.
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Affiliation(s)
- Miyoung Yoon
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
| | | | - Grace Zhixia Yan
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
| | - Harvey J Clewell
- Center for Human Health Assessment, The Hamner Institutes for Health Sciences, Research Triangle Park, NC, USA.
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