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Aakash A, Kulsoom R, Khan S, Siddiqui MS, Nabi D. Novel Models for Accurate Estimation of Air-Blood Partitioning: Applications to Individual Compounds and Complex Mixtures of Neutral Organic Compounds. J Chem Inf Model 2023; 63:7056-7066. [PMID: 37956246 PMCID: PMC10685450 DOI: 10.1021/acs.jcim.3c01288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 10/23/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023]
Abstract
The air-blood partition coefficient (Kab) is extensively employed in human health risk assessment for chemical exposure. However, current Kab estimation approaches either require an extensive number of parameters or lack precision. In this study, we present two novel and parsimonious models to accurately estimate Kab values for individual neutral organic compounds, as well as their complex mixtures. The first model, termed the GC×GC model, was developed based on the retention times of nonpolar chemical analytes on comprehensive two-dimensional gas chromatography (GC×GC). This model is unique in its ability to estimate the Kab values for complex mixtures of nonpolar organic chemicals. The GC×GC model successfully accounted for the Kab variance (R2 = 0.97) and demonstrated strong prediction power (RMSE = 0.31 log unit) for an independent set of nonpolar chemical analytes. Overall, the GC×GC model can be used to estimate Kab values for complex mixtures of neutral organic compounds. The second model, termed the partition model (PM), is based on two types of partition coefficients: octanol to water (Kow) and air to water (Kaw). The PM was able to effectively account for the variability in Kab data (n = 344), yielding an R2 value of 0.93 and root-mean-square error (RMSE) of 0.34 log unit. The predictive power and explanatory performance of the PM were found to be comparable to those of the parameter-intensive Abraham solvation models (ASMs). Additionally, the PM can be integrated into the software EPI Suite, which is widely used in chemical risk assessment for initial screening. The PM provides quick and reliable estimation of Kab compared to ASMs, while the GC×GC model is uniquely suited for estimating Kab values for complex mixtures of neutral organic compounds. In summary, our study introduces two novel and parsimonious models for the accurate estimation of Kab values for both individual compounds and complex mixtures.
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Affiliation(s)
- Ahmad Aakash
- Institute
of Environmental Science and Engineering (IESE), School of Civil and
Environmental Engineering (SCEE), National
University of Sciences and Technology (NUST), H-12, 48000 Islamabad, Pakistan
| | - Ramsha Kulsoom
- Institute
of Environmental Science and Engineering (IESE), School of Civil and
Environmental Engineering (SCEE), National
University of Sciences and Technology (NUST), H-12, 48000 Islamabad, Pakistan
| | - Saba Khan
- Institute
of Environmental Science and Engineering (IESE), School of Civil and
Environmental Engineering (SCEE), National
University of Sciences and Technology (NUST), H-12, 48000 Islamabad, Pakistan
| | - Musab Saeed Siddiqui
- Institute
of Environmental Science and Engineering (IESE), School of Civil and
Environmental Engineering (SCEE), National
University of Sciences and Technology (NUST), H-12, 48000 Islamabad, Pakistan
| | - Deedar Nabi
- Institute
of Environmental Science and Engineering (IESE), School of Civil and
Environmental Engineering (SCEE), National
University of Sciences and Technology (NUST), H-12, 48000 Islamabad, Pakistan
- GEOMAR
Helmholtz Center for Ocean Research, Wischhofstrasse 1-3, 24148 Kiel, Germany
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Minorczyk M, Czaja K, Starski A, Korcz W, Liszewska M, Lewiński R, Robson MG, Postupolski J, Struciński P. Assessment of Furan and Its Derivatives Intake with Home Prepared Meals and Characterization of Associated Risk for Polish Infants and Toddlers. Foods 2023; 12:3618. [PMID: 37835270 PMCID: PMC10572828 DOI: 10.3390/foods12193618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Furan and its derivatives are found in various heat-treated foods. Furan is classified as a possible human carcinogen. The European Union authorities recommend collecting data on the occurrence of these compounds, estimating consumer exposure, and taking measures to protect human health based on a scientific risk assessment. The aim of this study was to estimate the exposure of infants and toddlers to furan and its methyl derivatives-2-methylfuran, 3-methylfuran, and ∑2,5-dimethylfuran/2-ethylfuran-present in home-prepared foods and to characterize the associated health risks. The compounds of interest were determined using the HS-GC/MS. The risk was characterized by the calculation of the margin of exposure (MoE). Levels of furan and its derivatives in analyzed samples were in the range of
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Affiliation(s)
- Maria Minorczyk
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
| | - Katarzyna Czaja
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
| | - Andrzej Starski
- Department of Food Safety, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (A.S.); (J.P.)
| | - Wojciech Korcz
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
| | - Monika Liszewska
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
| | - Radosław Lewiński
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
| | - Mark Gregory Robson
- Department of Plant Biology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901, USA;
| | - Jacek Postupolski
- Department of Food Safety, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (A.S.); (J.P.)
| | - Paweł Struciński
- Department of Toxicology and Health Risk Assessment, National Institute of Public Health NIH—National Research Institute, 00-791 Warsaw, Poland; (M.M.); (K.C.); (W.K.); (M.L.); (R.L.)
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3
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Vevang KR, Zhang L, Grill AE, Hatsukami DK, Meier E, Nomura SO, Robien K, Peterson LA. Furan Metabolites Are Elevated in Users of Various Tobacco Products and Cannabis. Chem Res Toxicol 2023; 36:157-161. [PMID: 36716352 PMCID: PMC10035786 DOI: 10.1021/acs.chemrestox.2c00412] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Humans are exposed to furan, a toxicant and possible human carcinogen, through multiple sources including diet and tobacco smoke. The urinary metabolites of furan are derived from the reaction of its toxic metabolite with protein nucleophiles and are biomarkers of exposure and potential harm. An established isotopic dilution liquid-chromatography mass spectrometry method was used to measure these biomarkers in urine from users of e-cigarettes, cannabis, and/or combustible tobacco with/without reduced nicotine levels. Amounts of furan mercapturic acid metabolites were higher in these individuals relative to nonsmokers, indicating that they may be at risk for potential furan-derived toxicities.
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Affiliation(s)
- Karin R. Vevang
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Lin Zhang
- Division of Biostatistics, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Alex E. Grill
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Dorothy K. Hatsukami
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Department of Psychiatry, University of Minnesota, Minneapolis, MN,55455, USA
| | - Ellen Meier
- Department of Psychology, University of Wisconsin-Stevens Point, Stevens Point, WI, USA
| | - Sarah Oppeneer Nomura
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kim Robien
- Department of Exercise and Nutrition Sciences, George Washington University, Washington, DC 20052, USA
| | - Lisa A. Peterson
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Division of Environmental Health Sciences, University of Minnesota, Minneapolis, Minnesota 55455, USA
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4
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Kobets T, Smith BPC, Williams GM. Food-Borne Chemical Carcinogens and the Evidence for Human Cancer Risk. Foods 2022; 11:foods11182828. [PMID: 36140952 PMCID: PMC9497933 DOI: 10.3390/foods11182828] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Commonly consumed foods and beverages can contain chemicals with reported carcinogenic activity in rodent models. Moreover, exposures to some of these substances have been associated with increased cancer risks in humans. Food-borne carcinogens span a range of chemical classes and can arise from natural or anthropogenic sources, as well as form endogenously. Important considerations include the mechanism(s) of action (MoA), their relevance to human biology, and the level of exposure in diet. The MoAs of carcinogens have been classified as either DNA-reactive (genotoxic), involving covalent reaction with nuclear DNA, or epigenetic, involving molecular and cellular effects other than DNA reactivity. Carcinogens are generally present in food at low levels, resulting in low daily intakes, although there are some exceptions. Carcinogens of the DNA-reactive type produce effects at lower dosages than epigenetic carcinogens. Several food-related DNA-reactive carcinogens, including aflatoxins, aristolochic acid, benzene, benzo[a]pyrene and ethylene oxide, are recognized by the International Agency for Research on Cancer (IARC) as causes of human cancer. Of the epigenetic type, the only carcinogen considered to be associated with increased cancer in humans, although not from low-level food exposure, is dioxin (TCDD). Thus, DNA-reactive carcinogens in food represent a much greater risk than epigenetic carcinogens.
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Affiliation(s)
- Tetyana Kobets
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
- Correspondence: ; Tel.: +1-914-594-3105; Fax: +1-914-594-4163
| | - Benjamin P. C. Smith
- Future Ready Food Safety Hub, Nanyang Technological University, Singapore 639798, Singapore
| | - Gary M. Williams
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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5
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Kuroda K, Ishii Y, Takasu S, Matsushita K, Kijima A, Nohmi T, Umemura T. Toxicity, genotoxicity, and carcinogenicity of 2-methylfuran in a 90-day comprehensive toxicity study in gpt delta rats. Food Chem Toxicol 2022; 168:113365. [PMID: 35970270 DOI: 10.1016/j.fct.2022.113365] [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: 06/13/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 10/15/2022]
Abstract
2-Methylfuran (2-MF) exists naturally in foods and is used as a flavoring agent. Furan, the core structure of 2-MF, possesses hepatocarcinogenicity in rodents. Accumulation of toxicological information on furan derivatives is needed to elucidate their carcinogenic mode of action. In the current study, we examined the comprehensive toxicological studies of 2-MF using gpt delta rats. 2-MF was intragastrically administered to groups of 10 male and 10 female Sprague-Dawley gpt delta rats at a dose of 0, 1.2, 6, or 30 mg/kg/day for 13 weeks. Effects of 2-MF on the hepatobiliary system including an increase in serum alkaline phosphatase were observed in the 6 and 30 mg/kg groups, and cholangiofibrosis was found in the 30 mg/kg group. The no observed adverse effect level was set at 1.2 mg/kg/day for both sexes and 1.14 mg/kg/day was determined as the benchmark dose low. The acceptable daily intake was calculated to be 11.4 μg/kg/day. Increases in the number and areas of glutathione S-transferase placental form-positive foci in the 30 mg/kg group were apparent, suggesting the hepatocarcinogenicity of 2-MF in rats. By contrast, the lack of increase in in vivo mutagenicity in the liver implied that 2-MF hepatocarcinogenesis may not involve genotoxic mechanisms.
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Affiliation(s)
- Ken Kuroda
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Yuji Ishii
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Shinji Takasu
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Kohei Matsushita
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Aki Kijima
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Takehiko Nohmi
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan
| | - Takashi Umemura
- Division of Pathology, National Institute of Health Sciences, Kanagawa, Japan; Yamazaki University of Animal Health, Technology, Tokyo, Japan.
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6
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Rietjens IMCM, Michael A, Bolt HM, Siméon B, Andrea H, Nils H, Christine K, Angela M, Gloria P, Daniel R, Natalie T, Gerhard E. The role of endogenous versus exogenous sources in the exposome of putative genotoxins and consequences for risk assessment. Arch Toxicol 2022; 96:1297-1352. [PMID: 35249149 PMCID: PMC9013691 DOI: 10.1007/s00204-022-03242-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/01/2022] [Indexed: 12/21/2022]
Abstract
The "totality" of the human exposure is conceived to encompass life-associated endogenous and exogenous aggregate exposures. Process-related contaminants (PRCs) are not only formed in foods by heat processing, but also occur endogenously in the organism as physiological components of energy metabolism, potentially also generated by the human microbiome. To arrive at a comprehensive risk assessment, it is necessary to understand the contribution of in vivo background occurrence as compared to the ingestion from exogenous sources. Hence, this review provides an overview of the knowledge on the contribution of endogenous exposure to the overall exposure to putative genotoxic food contaminants, namely ethanol, acetaldehyde, formaldehyde, acrylamide, acrolein, α,β-unsaturated alkenals, glycation compounds, N-nitroso compounds, ethylene oxide, furans, 2- and 3-MCPD, and glycidyl esters. The evidence discussed herein allows to conclude that endogenous formation of some contaminants appears to contribute substantially to the exposome. This is of critical importance for risk assessment in the cases where endogenous exposure is suspected to outweigh the exogenous one (e.g. formaldehyde and acrolein).
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Affiliation(s)
- Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands.
| | - Arand Michael
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstr. 190, 8057, Zurich, Switzerland
| | - Hermann M Bolt
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors at TU Dortmund (IfADo), Ardeystr. 67, 44139, Dortmund, Germany
| | | | - Hartwig Andrea
- Department of Food Chemistry and Toxicology, Institute of Applied Biosciences (IAB), Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Hinrichsen Nils
- Food Oils and Fats Research, ADM Hamburg AG, Research, Seehafenstraße 24, 21079, Hamburg, Germany
| | - Kalisch Christine
- Department of Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Wurzburg, Germany
| | - Mally Angela
- Department of Toxicology, University of Würzburg, Versbacher Straße 9, 97078, Wurzburg, Germany
| | - Pellegrino Gloria
- Scientific Affairs and Research, Luigi Lavazza SpA, Strada Settimo, 410, 10156, Turin, Italy
| | - Ribera Daniel
- Regulatory and Scientific Affairs EMEA, Cargill R&D, Havenstraat 84, 1800, Vivoorde, Belgium
| | - Thatcher Natalie
- Food Safety, Mondelez International, Bournville Lane, Birmingham, B30 2LU, UK
| | - Eisenbrand Gerhard
- Department of Toxicology and Food Chemistry, University of Kaiserslautern, Kühler Grund 48/1, 69126, Heidelberg, Germany
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7
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Behl T, Rachamalla M, Najda A, Sehgal A, Singh S, Sharma N, Bhatia S, Al-Harrasi A, Chigurupati S, Vargas-De-La-Cruz C, Hobani YH, Mohan S, Goyal A, Katyal T, Solarska E, Bungau S. Applications of Adductomics in Chemically Induced Adverse Outcomes and Major Emphasis on DNA Adductomics: A Pathbreaking Tool in Biomedical Research. Int J Mol Sci 2021; 22:10141. [PMID: 34576304 PMCID: PMC8467560 DOI: 10.3390/ijms221810141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/04/2021] [Accepted: 09/13/2021] [Indexed: 01/06/2023] Open
Abstract
Adductomics novel and emerging discipline in the toxicological research emphasizes on adducts formed by reactive chemical agents with biological molecules in living organisms. Development in analytical methods propelled the application and utility of adductomics in interdisciplinary sciences. This review endeavors to add a new dimension where comprehensive insights into diverse applications of adductomics in addressing some of society's pressing challenges are provided. Also focuses on diverse applications of adductomics include: forecasting risk of chronic diseases triggered by reactive agents and predicting carcinogenesis induced by tobacco smoking; assessing chemical agents' toxicity and supplementing genotoxicity studies; designing personalized medication and precision treatment in cancer chemotherapy; appraising environmental quality or extent of pollution using biological systems; crafting tools and techniques for diagnosis of diseases and detecting food contaminants; furnishing exposure profile of the individual to electrophiles; and assisting regulatory agencies in risk assessment of reactive chemical agents. Characterizing adducts that are present in extremely low concentrations is an exigent task and more over absence of dedicated database to identify adducts is further exacerbating the problem of adduct diagnosis. In addition, there is scope of improvement in sample preparation methods and data processing software and algorithms for accurate assessment of adducts.
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Affiliation(s)
- Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; (T.B.); (A.S.); (S.S.); (N.S.)
| | - Mahesh Rachamalla
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK S7N 5E2, Canada;
| | - Agnieszka Najda
- Department of Vegetable Crops and Medicinal Plants, University of Life Sciences in Lublin, 20-950 Lublin, Poland
| | - Aayush Sehgal
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; (T.B.); (A.S.); (S.S.); (N.S.)
| | - Sukhbir Singh
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; (T.B.); (A.S.); (S.S.); (N.S.)
| | - Neelam Sharma
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; (T.B.); (A.S.); (S.S.); (N.S.)
| | - Saurabh Bhatia
- Natural & Medical Sciences Research Centre, University of Nizwa, Birkat Al Mauz, Nizwa 33, Oman; (S.B.); (A.A.-H.)
| | - Ahmed Al-Harrasi
- Natural & Medical Sciences Research Centre, University of Nizwa, Birkat Al Mauz, Nizwa 33, Oman; (S.B.); (A.A.-H.)
| | - Sridevi Chigurupati
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, Qassim University, Buraydah 52571, Saudi Arabia;
| | - Celia Vargas-De-La-Cruz
- Faculty of Pharmacy and Biochemistry, Academic Department of Pharmacology, Bromatology and Toxicology, Centro Latinoamericano de Enseñanza e Investigación en Bacteriología Alimentaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru;
- E-Health Research Center, Universidad de Ciencias y Humanidades, Lima 15001, Peru
| | - Yahya Hasan Hobani
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, Jazan University, Jazan 114, Saudi Arabia;
| | - Syam Mohan
- Substance Abuse and Toxicology Research Center, Jazan University, Jazan 114, Saudi Arabia;
| | - Amit Goyal
- GHG Khalsa College of Pharmacy, Gurusar Sadhar, Ludhiana 141104, India;
| | - Taruna Katyal
- RBMCH Division, ICMR Head Quarters, Ramalingaswami Bhawan, Ansari Nagar, New Delhi 110029, India;
| | - Ewa Solarska
- Department of Biotechnology, Microbiology and Human Nutrition, Faculty of Food Science and Biotechnology, University of Life Sciences in Lublin, 8 Skromna Street, 20-704 Lublin, Poland;
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania;
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Owumi SE, Bello SA, Idowu TB, Arunsi UO, Oyelere AK. Protocatechuic acid protects against hepatorenal toxicities in rats exposed to Furan. Drug Chem Toxicol 2021; 45:1840-1850. [PMID: 33645375 DOI: 10.1080/01480545.2021.1890109] [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] [Indexed: 01/03/2023]
Abstract
Furan formed in processed food is hepatotoxic and likely carcinogenic in humans. We investigated protocatechuic acid (PCA) protective role in rats' hepatorenal function treated with furan. Rats were grouped and treated as follows: Control, PCA (50 mg/kg), furan alone (8 mg/kg), furan + PCA1 (25 + 8 mg/kg), and furan + PCA2 (50 + 8 mg/kg). Upon sacrifice, evaluation of hepatorenal function, oxidative stress status, reactive oxygen and nitrogen species (RONS), lipid peroxidation (LPO), myeloperoxidase (MPO) activity, among nitric oxide (NO) levels were performed. Cytokine levels (IL-10, IL-1ß, TNF-alpha), Caspase 3 and 9 activities, and histopathological examination were also assessed. We found that the final body and relative liver weights changed significantly (p < 0.05) in treated groups. Hepatic transaminases, urea, and creatinine increased (p < 0.05) in furan only treated group, and reduced in PCA co-treated groups. The furan-induced decrease in antioxidant status increased RONS, and LPO levels were alleviated (p < 0.05) by PCA co-treatment. Furthermore, furan-mediated increase in NO, IL-1ß, TNF-alpha levels, MPO, Cas-3, and 9 activities and suppressed IL-10 levels was reversed accordingly in rats' kidney and liver co-treated with PCA. The extent of furan-mediated hepatorenal lesions was lessened in PCA co-treated rats. Our findings suggest that PCA protects against oxido-inflammatory pathways, enhanced caspases 3 and 9 activations induced by furan in rat hepatorenal system.
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Affiliation(s)
- Solomon E Owumi
- Cancer Research and Molecular Biology Laboratories, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Samuel A Bello
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Temitope B Idowu
- Nutrition and Industrial Biochemistry Laboratories, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Uche O Arunsi
- Department of Cancer Immunology and Biotechnology, School of Medicine, University of Nottingham, Nottingham, UK
| | - Adegboyega K Oyelere
- School of Biochemistry and Chemistry, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
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Kassem NOF, Peterson LA, Liles S, Kassem NO, Zaki FK, Lui KJ, Vevang KR, Dodder NG, Hoh E, Hovell MF. Urinary metabolites of furan in waterpipe tobacco smokers compared to non-smokers in home settings in the US. Toxicol Lett 2020; 333:202-210. [PMID: 32814080 PMCID: PMC10883161 DOI: 10.1016/j.toxlet.2020.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/23/2020] [Accepted: 08/03/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Determine uptake of furan, a potential human carcinogen, in waterpipe tobacco (WPT) smokers in home settings. METHODS We analysed data from a US convenience sample of 50 exclusive WPT smokers, mean age 25.3 years, and 25 non-smokers, mean age 25.5 years. For WPT smokers, data were collected at a home visit by research assistants during which participants smoked one WPT head of one brand for a mean of 33.1 min in their homes. Research assistants provided and prepared a WP for participants by weighing and loading 10 g of WPT in the WP head. At the completion of the smoking session, research assistants measured the remaining WPT. Cotinine and six furan metabolites were quantified in first morning urine samples provided on 2 consecutive days for non-smokers, and on the morning of a WPT smoking session and on the following morning for smokers. RESULTS WPT smokers consumed a mean of 2.99 g WPT. In WPT smokers, urinary cotinine levels increased significantly 26.1 times the following morning; however, urinary metabolites of furan did not increase significantly. Compared to non-smokers, 2 furan metabolites, N-acetyl-S-[1-(5-acetylamino-5-carboxylpentyl)-1H-pyrrol-3-yl]-L-cysteine and N-acetyl-S-[1-(5-amino-5-carboxypentyl)-1H-pyrrol-3-yl]-L-cysteine sulfoxide, were significantly higher in WPT smokers in pre and in post WPT smoking levels. CONCLUSIONS To enable a more rigorous assessment of furan exposure from WPT smoking, future research should determine furan concentrations in WPT smoke, quantify furan metabolites from users of various WPT brands; and extend the investigation to social settings where WPT smoking is habitually practiced.
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Affiliation(s)
- Nada O F Kassem
- Center for Behavioral Epidemiology and Community Health (CBEACH), Hookah Tobacco Studies Division, San Diego State University Research Foundation, San Diego, CA, 92123, United States.
| | - Lisa A Peterson
- Division of Environmental Health Sciences and the Masonic Cancer Center, University of Minnesota, Minneapolis, MN, 55455, United States
| | - Sandy Liles
- Center for Behavioral Epidemiology and Community Health (CBEACH), Hookah Tobacco Studies Division, San Diego State University Research Foundation, San Diego, CA, 92123, United States
| | - Noura O Kassem
- Center for Behavioral Epidemiology and Community Health (CBEACH), Hookah Tobacco Studies Division, San Diego State University Research Foundation, San Diego, CA, 92123, United States
| | - Flora K Zaki
- Center for Behavioral Epidemiology and Community Health (CBEACH), Hookah Tobacco Studies Division, San Diego State University Research Foundation, San Diego, CA, 92123, United States
| | - Kung-Jong Lui
- San Diego State University Research Foundation, 5250 Campanile Dr., San Diego, CA 92182, United States
| | - Karin R Vevang
- Division of Environmental Health Sciences and the Masonic Cancer Center, University of Minnesota, Minneapolis, MN, 55455, United States
| | - Nathan G Dodder
- San Diego State University Research Foundation, 5250 Campanile Dr., San Diego, CA 92182, United States
| | - Eunha Hoh
- School of Public Health, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182, United States
| | - Melbourne F Hovell
- Center for Behavioral Epidemiology and Community Health (CBEACH), Hookah Tobacco Studies Division, San Diego State University Research Foundation, San Diego, CA, 92123, United States
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10
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Protocatechuic acid modulates reproductive dysfunction linked to furan exposure in rats. Toxicology 2020; 442:152556. [DOI: 10.1016/j.tox.2020.152556] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022]
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11
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de Jongh J, Blaauboer BJ. In Vitro-based and In Vivo-hased Simulations of Benzene Uptake and Metabolism in Rats. Altern Lab Anim 2020. [DOI: 10.1177/026119299602400209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The metabolism of benzene was modelled in the rat by application of a physiologically based pharmacokinetic (PBPK) model. The model parameters were set by using reference physiological parameter values and reported partition coefficients from in vitro studies. Three sets of Vmax and Km values for benzene, derived from published in vitro studies, were substituted into the model while keeping all other model parameters constant. These model simulations were compared with two sets of empirical data on the metabolism or uptake of benzene after inhalation exposure. It was observed that the biotransformation parameter sets derived in vitro predicted all empirical data within a factor of two. In addition, it was observed that simulations across the two sets of empirical data which used biotransformation parameters obtained by fitting to one set of data to simulate the other set, led to results comparable to those in the in vitro-based simulations. It is concluded that the results of in vitro studies can be directly applied in a PBPK model in order to estimate the in vivo uptake and metabolism of benzene on the basis of previously determined model parameter assumptions. These results support earlier studies on the application of in vitro techniques for deriving PBPK model parameters. On the basis of other studies on the simulation of benzene kinetics, it is also concluded that additional studies are required to extend the validity of this approach for other compounds.
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Affiliation(s)
- Joost de Jongh
- Research Institute of Toxicology (RITOX), Utrecht University, P.O. Box 80.176, 3508 TD Utrecht, The Netherlands
| | - Bas J. Blaauboer
- Research Institute of Toxicology (RITOX), Utrecht University, P.O. Box 80.176, 3508 TD Utrecht, The Netherlands
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12
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Blaauboer BJ, Bayliss MK, Castell JV, Evelo CT, Frazier JM, Groen K, Gülden M, Guillouzo A, Hissink AM, Houston JB, Johanson G, de Jongh J, Kedderis GL, Reinhardt CA, van de Sandt JJ, Semino G. The Use of Biokinetics and in Vitro Methods in Toxicological Risk Evaluation. Altern Lab Anim 2020. [DOI: 10.1177/026119299602400408] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
| | - Martin K. Bayliss
- Department of Bioanalysis and Drug Metabolism, Glaxo Wellcome, Park Road, Ware, Herts. SG12 ODP, UK
| | - Jose V. Castell
- Unidad de Hepatologia Experimental, Hospital Universitario La Fe, Avda de Campanar 21, 46009 Valencia, Spain
| | - Chris T.A. Evelo
- Department of Pharmacology, Section of Toxicology, University of Limburg, 6200 MD Maastricht, The Netherlands
| | - John M. Frazier
- US Air Force, Armstrong Laboratory, Wright Patterson Air Force Base, OH 45433, USA
| | - Kees Groen
- Department of Clinical Pharmacokinetics, Janssen Research Foundation, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Michael Gülden
- Cell Toxicology Section, Institute of Toxicology, University of Kiel, Weimarer Strasse 8, 24106 Kiel, Germany
| | - André Guillouzo
- INSERM U49, Unité de Recherches Hépatologiques, Hôpital de Pontchaillou, 35033 Rennes Cedex, France
| | - Arendina M. Hissink
- Toxicology Division, TNO Nutrition and Food Research Institute, 3700 AJ Zeist, The Netherlands
| | - J. Brian Houston
- Department of Pharmacy, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gunnar Johanson
- Department of Toxicology and Chemistry, National Institute for Working Life, 171 84 Solna, Sweden
| | - Joost de Jongh
- RITOX, Utrecht University, 3508 TD Utrecht, The Netherlands
| | - Gregory L. Kedderis
- Chemical Industry Institute of Toxicology CIIT, Research Triangle Park, NC 27709, USA
| | - Christoph A. Reinhardt
- Swiss Alternatives to Animal Testing (SAAT), P.O. Box 14, 8614 Bertschikon-Zurich, Switzerland
| | | | - Giovanna Semino
- Laboratory of Toxicology, Institute of Pharmacological Sciences, Via Balzaretti 9, 20133 Milan, Italy
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13
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Teodoro JS, Silva R, Aguiar A, Sobral AJFN, Rolo AP, Palmeira CM. Exploration of the cellular effects of the high-dose, long-term exposure to coffee roasting product furan and its by-product cis-2-butene-1,4-dial on human and rat hepatocytes. Toxicol Mech Methods 2020; 30:536-545. [PMID: 32544017 DOI: 10.1080/15376516.2020.1780361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Coffee is the most popular hot beverage and caffeine is the most used psychoactive drug in the world. Roasting of coffee beans leads to the generation of minute quantities of undesirable compounds, such as furan. It is now thought that the toxicity of furan derives from its processing by CYP450 family of detoxifying enzymes, leading to the formation of cis-2-butene-1,4-dial (BDA). BDA has known cytotoxicity capacities, binding to proteins, nucleic acids, and glutathione (GSH). BDA also appears to mediate furan's toxic effects, since the inhibition of CYP450 family impedes the aforementioned toxicological effects of furan. There are some studies performed on furan's toxicity, but very few on BDA. Furthermore, the doses used in these studies appear to be fairly high when compared with the expected dosage one could be exposed to in a standard day. As such, to understand if furan and BDA could have toxic effects using more realistic doses and longer time frames, human and rat hepatocytes were exposed to furan or BDA for up to 96 h, and several biochemical parameters were assessed. We report here that human hepatocytes were more sensitive than rat's, in particular to furan, for we show a decrease in MTT reduction, ATP levels and increase in carbonyl formation and 8-OHdG accumulation in the longer time points. BDA was mostly ineffective, which we attribute to a low import rate into the cells. In conclusion, we show that there is potential for harm from furan in high doses, which should be carefully addressed.
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Affiliation(s)
- João S Teodoro
- Department of Life Sciences of Faculty of Sciences and Technology, of the University of Coimbra, Coimbra, Portugal.,Center for Neurosciences and Cell Biology, of the University of Coimbra, Coimbra, Portugal
| | - Rui Silva
- Center for Neurosciences and Cell Biology, of the University of Coimbra, Coimbra, Portugal
| | - António Aguiar
- Chemistry Department, FCTUC, University of Coimbra, Coimbra, Portugal
| | | | - Anabela P Rolo
- Department of Life Sciences of Faculty of Sciences and Technology, of the University of Coimbra, Coimbra, Portugal.,Center for Neurosciences and Cell Biology, of the University of Coimbra, Coimbra, Portugal
| | - Carlos M Palmeira
- Department of Life Sciences of Faculty of Sciences and Technology, of the University of Coimbra, Coimbra, Portugal.,Center for Neurosciences and Cell Biology, of the University of Coimbra, Coimbra, Portugal
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14
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Prasse C, von Gunten U, Sedlak DL. Chlorination of Phenols Revisited: Unexpected Formation of α,β-Unsaturated C 4-Dicarbonyl Ring Cleavage Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:826-834. [PMID: 31904937 PMCID: PMC7665061 DOI: 10.1021/acs.est.9b04926] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Despite decades of research on the fate of phenolic compounds when water is disinfected with hypochlorous acid (HOCl), there is still considerable uncertainty regarding the formation mechanisms and identity of ring cleavage products, especially at higher chlorine doses. This study focuses on the formation of electrophilic ring cleavage products-a class of compounds that poses potential health risks at relatively low concentrations-from the reactions of phenols with chlorine. By monitoring the formation of products of reactions between ring cleavage products and the model nucleophile N-α-acetyl-lysine, we identified the α,β-unsaturated dialdehyde 2-butene-1,4-dial (BDA) and its chlorinated analogue, chloro-2-butene-1,4-dial (Cl-BDA), after the chlorination of phenol, para- and ortho-substituted chlorophenols (2-Cl, 4-Cl, 2,4-diCl-, 2,6-diCl, and 2,4,6-triCl-phenol), and 3,5-di-Cl-catechol. Maximum yields of BDA were observed when chlorine was present in large excess (HOCl/phenol ratios of 30:1 to 50:1), with yields ranging from 18% for phenol to 46% for 3,5-diCl-catechol. BDA and Cl-BDA formation was also observed during the chlorination of brominated phenols. For methyl-substituted phenols, the presence of methyl substituents in both positions ortho to the hydroxy group inhibited BDA and Cl-BDA formation, but the chlorination of cresols and 2,3-dimethylphenol yielded methyl- and dimethyl-BDA species. This study provides new insights into the formation of reactive and toxic electrophiles during chlorine disinfection. It also provides evidence for the importance of phenoxy radicals produced by one-electron transfer reactions initiated by chlorine in the production of dicarbonyl ring cleavage products.
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Affiliation(s)
- Carsten Prasse
- Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland
- School of Architecture, Civil, and Environmental Engineering (ENAC), École Polytechnique Fedérale de Lausanne, 1015 Lausanne, Switzerland
| | - David L. Sedlak
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720, USA
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15
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Tăbăran AF, O’Sullivan MG, Seabloom DE, Vevang KR, Smith WE, Wiedmann TS, Peterson LA. Inhaled Furan Selectively Damages Club Cells in Lungs of A/J Mice. Toxicol Pathol 2019; 47:842-850. [PMID: 31426723 PMCID: PMC6814549 DOI: 10.1177/0192623319869306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Furan, a possible human carcinogen, is a product of incomplete combustion and is present in cigarette smoke, engine exhaust, and processed food. Oral administration induces liver toxicity and carcinogenesis in F344 rats and B6C3F1 mice. To assess possible adverse effects from inhalation, A/J mice were nose-only exposed for 3 hours to furan (0, 30, 75, 150, 300, or 600 ppmv) and euthanized after 24 hours, 48 hours, or 1 week. Histopathology evaluation revealed bronchiolar club cell necrosis (diffuse, marked) with airway denudation following exposure to 300 and 600 ppmv furan with evidence of club cell regeneration and partial repair after 1 week. Initial signs of hepatotoxicity were observed in the 150 ppmv furan-exposed group. Acute necrosis and mineralization were observed in livers at 24 and 48 hours with hepatocyte regeneration by 1-week postexposure in mice exposed to 300 and 600 ppmv furan; the 300 ppmv exposed group had multifocal mineralization that evoked a mild granulomatous response. Measurement of urinary furan metabolites confirmed that the mice metabolized furan to the toxic intermediate, cis-2-butene-1,4-dial. These observations indicate that inhaled furan is toxic to lungs with club cells as the target as well as liver.
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Affiliation(s)
- Alexandru-Flaviu Tăbăran
- College of Veterinary Medicine, University of Minnesota,
St. Paul, Minnesota, USA
- Comparative Pathology Shared Resource, Masonic Cancer
Center, University of Minnesota, St. Paul, Minnesota, USA
| | - M. Gerard O’Sullivan
- College of Veterinary Medicine, University of Minnesota,
St. Paul, Minnesota, USA
- Comparative Pathology Shared Resource, Masonic Cancer
Center, University of Minnesota, St. Paul, Minnesota, USA
| | - Donna E. Seabloom
- AeroCore Testing Service, Department of Otolaryngology,
University of Minnesota, Minneapolis, Minnesota, USA
- Masonic Cancer Center, University of Minnesota,
Minneapolis, Minnesota, USA
| | - Karin R. Vevang
- Masonic Cancer Center, University of Minnesota,
Minneapolis, Minnesota, USA
| | - William E. Smith
- Masonic Cancer Center, University of Minnesota,
Minneapolis, Minnesota, USA
| | - Timothy S. Wiedmann
- Department of Pharmaceutics, University of Minnesota,
Minneapolis, Minnesota, USA
| | - Lisa A. Peterson
- Masonic Cancer Center, University of Minnesota,
Minneapolis, Minnesota, USA
- Division of Environmental Health Sciences, University of
Minnesota, Minneapolis, Minnesota, USA
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16
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Rietjens IMCM, Dussort P, Günther H, Hanlon P, Honda H, Mally A, O'Hagan S, Scholz G, Seidel A, Swenberg J, Teeguarden J, Eisenbrand G. Exposure assessment of process-related contaminants in food by biomarker monitoring. Arch Toxicol 2018; 92:15-40. [PMID: 29302712 PMCID: PMC5773647 DOI: 10.1007/s00204-017-2143-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/13/2017] [Indexed: 12/18/2022]
Abstract
Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.
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Affiliation(s)
- Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - P Dussort
- International Life Sciences Institute, Europe (ILSI Europe), Av E. Mounier 83, Box 6, 1200, Brussels, Belgium.
| | - Helmut Günther
- Mondelēz International, Postfach 10 78 40, 28078, Bremen, Germany
| | - Paul Hanlon
- Abbott Nutrition, 3300 Stelzer Road, Dept. 104070, Bldg. RP3-2, Columbus, OH, 43219, USA
| | - Hiroshi Honda
- KAO Corporation, R&D Safety Science Research, 2606 Akabane, Ichikai-Machi, Haga-Gun, Tochigi, 321 3497, Japan
| | - Angela Mally
- Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078, Würzburg, Germany
| | - Sue O'Hagan
- PepsiCo Europe, 4 Leycroft Road, Leicester, LE4 1ET, UK
| | - Gabriele Scholz
- Nestlé Research Center, Vers-chez-les-Blanc, PO Box 44, 1000, Lausanne 26, Switzerland
| | - Albrecht Seidel
- Biochemical Institute for Environmental Carcinogens Prof. Dr. Gernot Grimmer-Foundation, Lurup 4, 22927, Grosshansdorf, Germany
| | - James Swenberg
- Environmental Science and Engineering, UNC-Chapel Hill Cancer Genetics, 253c Rosenau Hall, Chapel Hill, NC, USA
| | - Justin Teeguarden
- Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Gerhard Eisenbrand
- Division of Food Chemistry and Toxicology, Department of Chemistry, University of Kaiserslautern, P.O. Box 3049, 67653, Kaiserslautern, Germany
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17
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Knutsen HK, Alexander J, Barregård L, Bignami M, Brüschweiler B, Ceccatelli S, Cottrill B, Dinovi M, Edler L, Grasl-Kraupp B, Hogstrand C, Hoogenboom LR, Nebbia CS, Oswald IP, Petersen A, Rose M, Roudot AC, Schwerdtle T, Vleminckx C, Vollmer G, Chipman K, De Meulenaer B, Dinovi M, Mennes W, Schlatter J, Schrenk D, Baert K, Dujardin B, Wallace H. Risks for public health related to the presence of furan and methylfurans in food. EFSA J 2017; 15:e05005. [PMID: 32625300 PMCID: PMC7009982 DOI: 10.2903/j.efsa.2017.5005] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The European Commission asked EFSA for a scientific evaluation on the risk to human health of the presence of furan and methylfurans (2-methylfuran, 3-methylfuran and 2,5-dimethylfuran) in food. They are formed in foods during thermal processing and can co-occur. Furans are produced from several precursors such as ascorbic acid, amino acids, carbohydrates, unsaturated fatty acids and carotenoids, and are found in a variety of foods including coffee and canned and jarred foods. Regarding furan occurrence, 17,056 analytical results were used in the evaluation. No occurrence data were received on methylfurans. The highest exposures to furan were estimated for infants, mainly from ready-to-eat meals. Grains and grain-based products contribute most for toddlers, other children and adolescents. In adults, elderly and very elderly, coffee is the main contributor to dietary exposure. Furan is absorbed from the gastrointestinal tract and is found in highest amounts in the liver. It has a short half-life and is metabolised by cytochrome P450 2E1 (CYP2E1) to the reactive metabolite, cis-but-2-ene-1,4-dialdehyde (BDA). BDA can bind covalently to amino acids, proteins and DNA. Furan is hepatotoxic in rats and mice with cholangiofibrosis in rats and hepatocellular adenomas/carcinomas in mice being the most prominent effects. There is limited evidence of chromosomal damage in vivo and a lack of understanding of the underlying mechanism. Clear evidence for indirect mechanisms involved in carcinogenesis include oxidative stress, gene expression alterations, epigenetic changes, inflammation and increased cell proliferation. The CONTAM Panel used a margin of exposure (MOE) approach for the risk characterisation using as a reference point a benchmark dose lower confidence limit for a benchmark response of 10% of 0.064 mg/kg body weight (bw) per day for the incidence of cholangiofibrosis in the rat. The calculated MOEs indicate a health concern. This conclusion was supported by the calculated MOEs for the neoplastic effects.
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18
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Bi K, Zhang L, Qiao X, Xu Z. Tea Polyphenols as Inhibitors of Furan Formed in the Maillard Model System and Canned Coffee Model. J Food Sci 2017; 82:1271-1277. [DOI: 10.1111/1750-3841.13691] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 01/01/2017] [Accepted: 02/19/2017] [Indexed: 11/28/2022]
Affiliation(s)
- K.H. Bi
- College of Food Science and Engineering; Shandong Agricultural Univ.; Tai'an 271018 China
| | - L. Zhang
- College of Food Science and Engineering; Shandong Agricultural Univ.; Tai'an 271018 China
| | - X.G. Qiao
- College of Food Science and Engineering; Shandong Agricultural Univ.; Tai'an 271018 China
| | - Z.X. Xu
- College of Food Science and Engineering; Shandong Agricultural Univ.; Tai'an 271018 China
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19
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Von Tungeln LS, Walker NJ, Olson GR, Mendoza MCB, Felton RP, Thorn BT, Marques MM, Pogribny IP, Doerge DR, Beland FA. Low dose assessment of the carcinogenicity of furan in male F344/N Nctr rats in a 2-year gavage study. Food Chem Toxicol 2017; 99:170-181. [PMID: 27871980 PMCID: PMC5375162 DOI: 10.1016/j.fct.2016.11.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 01/11/2023]
Abstract
Furan is a volatile organic chemical that is a contaminant in many common foods. Furan is hepatocarcinogenic in mice and rats; however, the risk to humans from dietary exposure to furan cannot be estimated accurately because the lowest tested dose of furan in a 2-year bioassay in rats gave nearly a 100% incidence of cholangiocarcinoma. To provide bioassay data that can be used in preparing risk assessments, the carcinogenicity of furan was determined in male F344/N Nctr rats administered 0, 0.02, 0.044, 0.092, 0.2, 0.44, 0.92, and 2 mg furan/kg body weight (BW) by gavage 5 days/week for 2 years. Exposure to furan was associated with the development of malignant mesothelioma on membranes surrounding the epididymis and on the testicular tunics, with the increase being significant at 2 mg furan/kg BW. There was also a dose-related increase in the incidence of mononuclear cell leukemia, with the increase in incidence being significant at 0.092, 0.2, 0.92, and 2 mg furan/kg BW. Dose-related non-neoplastic liver lesions included cholangiofibrosis, mixed cell foci, basophilic foci, biliary tract hyperplasia, oval cell hyperplasia, regenerative hyperplasia, and cytoplasmic vacuolization. The most sensitive non-neoplastic lesion was cholangiofibrosis, the frequency of which increased significantly at 0.2 mg furan/kg BW.
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Affiliation(s)
- Linda S Von Tungeln
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - Nigel J Walker
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, United States
| | - Greg R Olson
- Toxicologic Pathology Associates, Jefferson, AR 72079, United States
| | - Maria C B Mendoza
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - Robert P Felton
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - Brett T Thorn
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - M Matilde Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - Daniel R Doerge
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, United States
| | - Frederick A Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, United States.
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20
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Nunes J, Martins IL, Charneira C, Pogribny IP, de Conti A, Beland FA, Marques MM, Jacob CC, Antunes AMM. New insights into the molecular mechanisms of chemical carcinogenesis: In vivo adduction of histone H2B by a reactive metabolite of the chemical carcinogen furan. Toxicol Lett 2016; 264:106-113. [PMID: 27825936 DOI: 10.1016/j.toxlet.2016.10.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 12/19/2022]
Abstract
Furan is a rodent hepatocarcinogen ubiquitously found in the environment and heat-processed foods. Furan undergoes cytochrome P450 2E1-catalyzed bioactivation to cis-2-butene-1,4-dial (BDA), which has been shown to form an electrophilic conjugate (GSH-BDA) with glutathione. Both BDA and GSH-BDA yield covalent adducts with lysine residues in proteins. Dose- and time-dependent epigenetic histone alterations have been observed in furan-treated rats. While the covalent modification of histones by chemical carcinogens has long been proposed, histone-carcinogen adducts have eluded detection in vivo. In this study, we investigated if the covalent modification of histones by furan may occur in vivo prior to epigenetic histone alterations. Using a "bottom-up" methodology, involving the analysis of tryptic peptides by liquid chromatography - high resolution mass spectrometry, we obtained evidence for a cross-link between GSH-BDA and lysine 107 of histone H2B isolated from the livers of male F344 rats treated with tumorigenic doses of furan. This cross-link was detected at the shortest treatment period (90 days) in the lowest dose group (0.92mg/kg body weight/day), prior to the identification of epigenetic changes, and occurred at a lysine residue that is a target for epigenetic modifications and crucial for nucleosome stability. Our results represent the first unequivocal proof of the occurrence of carcinogen-modified histones in vivo and suggest that such modification happens at the initial stages of furan-induced carcinogenesis. This type of alteration may be general in scope, opening new insights into the mechanisms of chemical carcinogenesis/toxicity and new opportunities for the development of early compound-specific biomarkers of exposure.
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Affiliation(s)
- João Nunes
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Inês L Martins
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Catarina Charneira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Aline de Conti
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Frederick A Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - M Matilde Marques
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Cristina C Jacob
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Alexandra M M Antunes
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
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21
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Webster AF, Lambert IB, Yauk CL. Toxicogenomics Case Study: Furan. TOXICOGENOMICS IN PREDICTIVE CARCINOGENICITY 2016. [DOI: 10.1039/9781782624059-00390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Development of pragmatic methodologies for human health risk assessment is required to address current regulatory challenges. We applied three toxicogenomic approaches—quantitative, predictive, and mechanistic—to a case study in mice exposed for 3 weeks to the hepatocarcinogen furan. We modeled the dose response of a variety of transcriptional endpoints and found that they produced benchmark doses similar to the furan-dependent cancer benchmark doses. Meta-analyses showed strong similarity between furan-dependent gene expression changes and those associated with several hepatic pathologies. Molecular pathways facilitated the development of a molecular mode of action for furan-induced hepatocellular carcinogenicity. Finally, we compared transcriptomic profiles derived from formalin-fixed and paraffin-embedded (FFPE) samples with those from high-quality frozen samples to evaluate whether archival samples are a viable option for toxicogenomic studies. The advantage of using FFPE tissues is that they are very well characterized (phenotypically); the disadvantage is that formalin degrades biomacromolecules, including RNA. We found that FFPE samples can be used for toxicogenomics using a ribo-depletion RNA-seq protocol. Our case study demonstrates the utility of toxicogenomics data to human health risk assessment, the potential of archival FFPE tissue samples, and identifies viable strategies toward the reduction of animal usage in chemical testing.
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Affiliation(s)
- A. Francina Webster
- Department of Biology, Carleton University 1125 Colonel By Drive Ottawa ON Canada
- Environmental Health Science and Research Bureau, Health Canada, Tunney's Pasture 50 Colombine Driveway Ottawa ON Canada
| | - Iain B. Lambert
- Department of Biology, Carleton University 1125 Colonel By Drive Ottawa ON Canada
| | - Carole L. Yauk
- Environmental Health Science and Research Bureau, Health Canada, Tunney's Pasture 50 Colombine Driveway Ottawa ON Canada
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Yauk CL, Buick JK, Williams A, Swartz CD, Recio L, Li H, Fornace AJ, Thomson EM, Aubrecht J. Application of the TGx-28.65 transcriptomic biomarker to classify genotoxic and non-genotoxic chemicals in human TK6 cells in the presence of rat liver S9. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2016; 57:243-60. [PMID: 26946220 PMCID: PMC5021161 DOI: 10.1002/em.22004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 05/05/2023]
Abstract
In vitro transcriptional signatures that predict toxicities can facilitate chemical screening. We previously developed a transcriptomic biomarker (known as TGx-28.65) for classifying agents as genotoxic (DNA damaging) and non-genotoxic in human lymphoblastoid TK6 cells. Because TK6 cells do not express cytochrome P450s, we confirmed accurate classification by the biomarker in cells co-exposed to 1% 5,6 benzoflavone/phenobarbital-induced rat liver S9 for metabolic activation. However, chemicals may require different types of S9 for activation. Here we investigated the response of TK6 cells to higher percentages of Aroclor-, benzoflavone/phenobarbital-, or ethanol-induced rat liver S9 to expand TGx-28.65 biomarker applicability. Transcriptional profiles were derived 3 to 4 hr following a 4 hr co-exposure of TK6 cells to test chemicals and S9. Preliminary studies established that 10% Aroclor- and 5% ethanol-induced S9 alone did not induce the TGx-28.65 biomarker genes. Seven genotoxic and two non-genotoxic chemicals (and concurrent solvent and positive controls) were then tested with one of the S9s (selected based on cell survival and micronucleus induction). Relative survival and micronucleus frequency was assessed by flow cytometry in cells 20 hr post-exposure. Genotoxic/non-genotoxic chemicals were accurately classified using the different S9s. One technical replicate of cells co-treated with dexamethasone and 10% Aroclor-induced S9 was falsely classified as genotoxic, suggesting caution in using high S9 concentrations. Even low concentrations of genotoxic chemicals (those not causing cytotoxicity) were correctly classified, demonstrating that TGx-28.65 is a sensitive biomarker of genotoxicity. A meta-analysis of datasets from 13 chemicals supports that different S9s can be used in TK6 cells, without impairing classification using the TGx-28.65 biomarker.
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Affiliation(s)
- Carole L. Yauk
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
| | - Julie K. Buick
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
| | - Andrew Williams
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
| | - Carol D. Swartz
- Integrated Laboratory Systems IncResearch Triangle ParkNorth Carolina
| | - Leslie Recio
- Integrated Laboratory Systems IncResearch Triangle ParkNorth Carolina
| | - Heng‐Hong Li
- Department of Biochemistry and Molecular and Cellular BiologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
- Department of OncologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
| | - Albert J. Fornace
- Department of Biochemistry and Molecular and Cellular BiologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
- Department of OncologyGeorgetown University Medical CenterWashingtonDistrict of Columbia
| | - Errol M. Thomson
- Environmental Health Science and Research Bureau, Health CanadaOttawaOntarioCanada
| | - Jiri Aubrecht
- Drug Safety Research and Development, Pfizer IncGrotonConnecticut
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Churchwell MI, Scheri RC, Von Tungeln LS, Gamboa da Costa G, Beland FA, Doerge DR. Evaluation of serum and liver toxicokinetics for furan and liver DNA adduct formation in male Fischer 344 rats. Food Chem Toxicol 2015; 86:1-8. [PMID: 26364877 DOI: 10.1016/j.fct.2015.08.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 08/27/2015] [Accepted: 08/29/2015] [Indexed: 11/26/2022]
Abstract
Furan is a food processing contaminant found in many common cooked foods that induces liver toxicity and liver cancer in animal models treated with sufficient doses. The metabolism of furan occurs primarily in the liver where CYP 2E1 produces a highly reactive bis-electrophile, cis-2-butene-1,4-dial (BDA). BDA reacts with nucleophilic groups in amino acids and DNA in vitro to form covalent adducts. Evidence for BDA-nucleoside adduct formation in vivo is limited but important for assessing the carcinogenic hazard of dietary furan. This study used controlled dosing with furan in Fischer 344 rats to measure serum and liver toxicokinetics and the possible formation of BDA-nucleoside adducts in vivo. After gavage exposure, furan concentrations in the liver were consistently higher than those in whole blood (∼6-fold), which is consistent with portal vein delivery of a lipophilic compound into the liver. Formation of BDA-2'-deoxycytidine in furan-treated rat liver DNA was not observed using LC/MS/MS after single doses as high as 9.2 mg/kg bw or repeated dosing for up to 360 days above a consistent background level (1-2 adducts per 10(8) nucleotides). This absence of BDA-nucleoside adduct formation is consistent with the general lack of evidence for genotoxicity of furan in vivo.
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Affiliation(s)
- M I Churchwell
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - R C Scheri
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - L S Von Tungeln
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - G Gamboa da Costa
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - F A Beland
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA
| | - D R Doerge
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
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Webster AF, Zumbo P, Fostel J, Gandara J, Hester SD, Recio L, Williams A, Wood CE, Yauk CL, Mason CE. Mining the Archives: A Cross-Platform Analysis of Gene Expression Profiles in Archival Formalin-Fixed Paraffin-Embedded Tissues. Toxicol Sci 2015; 148:460-72. [PMID: 26361796 PMCID: PMC4659533 DOI: 10.1093/toxsci/kfv195] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Formalin-fixed paraffin-embedded (FFPE) tissue samples represent a potentially invaluable resource for transcriptomic research. However, use of FFPE samples in genomic studies has been limited by technical challenges resulting from nucleic acid degradation. Here we evaluated gene expression profiles derived from fresh-frozen (FRO) and FFPE mouse liver tissues preserved in formalin for different amounts of time using 2 DNA microarray protocols and 2 whole-transcriptome sequencing (RNA-seq) library preparation methodologies. The ribo-depletion protocol outperformed the other methods by having the highest correlations of differentially expressed genes (DEGs), and best overlap of pathways, between FRO and FFPE groups. The effect of sample time in formalin (18 h or 3 weeks) on gene expression profiles indicated that test article treatment, not preservation method, was the main driver of gene expression profiles. Meta- and pathway analyses indicated that biological responses were generally consistent for 18 h and 3 week FFPE samples compared with FRO samples. However, clear erosion of signal intensity with time in formalin was evident, and DEG numbers differed by platform and preservation method. Lastly, we investigated the effect of time in paraffin on genomic profiles. Ribo-depletion RNA-seq analysis of 8-, 19-, and 26-year-old control blocks resulted in comparable quality metrics, including expected distributions of mapped reads to exonic, untranslated region, intronic, and ribosomal fractions of the transcriptome. Overall, our results indicate that FFPE samples are appropriate for use in genomic studies in which frozen samples are not available, and that ribo-depletion RNA-seq is the preferred method for this type of analysis in archival and long-aged FFPE samples.
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Affiliation(s)
- A Francina Webster
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9, Canada; Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6, Canada
| | - Paul Zumbo
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065
| | - Jennifer Fostel
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
| | - Jorge Gandara
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065
| | - Susan D Hester
- Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27709
| | - Leslie Recio
- ILS, Inc., PO Box 13501, Research Triangle Park, North Carolina 27709
| | - Andrew Williams
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9, Canada
| | - Charles E Wood
- Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27709
| | - Carole L Yauk
- *Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9, Canada;
| | - Christopher E Mason
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York 10065; The Feil Family Brain and Mind Research Institute (BMRI), 413 East 69th Street, New York, New York 10021; and The HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute for Computational Biomedicine, 1305 York Avenue, New York, New York 10065
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Terrell AN, Huynh M, Grill AE, Kovi RC, O'Sullivan MG, Guttenplan JB, Ho YY, Peterson LA. Mutagenicity of furan in female Big Blue B6C3F1 mice. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 770:46-54. [PMID: 25344163 PMCID: PMC4209239 DOI: 10.1016/j.mrgentox.2014.04.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 03/12/2014] [Accepted: 04/10/2014] [Indexed: 11/22/2022]
Abstract
Furan is an abundant food and environmental contaminant that is a potent liver carcinogen in rodent models. To determine if furan is genotoxic in vivo, female B6C3F1 Big Blue transgenic mice were treated with 15 mg/kg bw furan by gavage 5 days a week for 6 weeks, or once weekly for 3 weeks. Liver cII transgene mutation-frequency and mutation spectra were determined. Furan did not increase the mutation frequency under either treatment condition. In the 6-week treatment regimen, there was a change in the cII transgene mutation-spectrum, with the fraction of GC to AT transitions significantly reduced. The only other significant change was an increase in GC to CG transversions; these represented a minor contribution to the overall mutation spectrum. A much larger furan-dependent shift was observed in the 3-week study. There was a significant increase in transversion mutations, predominantly GC to TA transversions as well as smaller non-significant changes in GC to CG and AT to TA transversions. To determine if these mutations were caused by cis-2-butene-1,4-dial (BDA), a reactive metabolite of furan, the mutagenic activity and the mutation spectrum of BDA was determined in vitro, in Big Blue mouse embryonic fibroblasts. This compound did not increase the cII gene mutation-frequency but caused a substantial increase in AT to CG transversions. This increase, however, lost statistical significance when adjusted for multiple comparisons. Together, these findings suggest that BDA may not be directly responsible for the in-vivo effects of furan on mutational spectra. Histopathological analysis of livers from furan-treated mice revealed that furan induced multifocal, hepatocellular necrosis admixed with reactive leukocytes and pigment-laden Kupffer cells, enhanced oval-cell hyperplasia, and increased hepatocyte mitoses, some of which were atypical. An indirect mechanism of genotoxicity is proposed in which chronic toxicity followed by inflammation and secondary cell proliferation triggers cancer development in furan-exposed rodents.
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Affiliation(s)
- Ashley N Terrell
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Mailee Huynh
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Alex E Grill
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Ramesh C Kovi
- Masonic Cancer Center Comparative Pathology Shared Resource, University of Minnesota, St. Paul, MN 55108, United States.
| | - M Gerard O'Sullivan
- Masonic Cancer Center Comparative Pathology Shared Resource, University of Minnesota, St. Paul, MN 55108, United States.
| | - Joseph B Guttenplan
- Department of Basic Science and Craniofacial Biology, and Environmental Medicine, New York University Dental and Medical Schools, New York, NY 10010, United States.
| | - Yen-Yi Ho
- Division of Biostatistics, University of Minnesota, Minneapolis, MN 55455, United States.
| | - Lisa A Peterson
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, United States.
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Gates LA, Phillips MB, Matter BA, Peterson LA. Comparative metabolism of furan in rodent and human cryopreserved hepatocytes. Drug Metab Dispos 2014; 42:1132-6. [PMID: 24751574 PMCID: PMC4053996 DOI: 10.1124/dmd.114.057794] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/21/2014] [Indexed: 11/22/2022] Open
Abstract
Furan is a liver toxicant and carcinogen in rodents. Although humans are most likely exposed to furan through a variety of sources, the effect of furan exposure on human health is still unknown. In rodents, furan requires metabolism to exert its toxic effects. The initial product of the cytochrome P450 2E1-catalyzed oxidation is a reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). BDA is toxic and mutagenic and consequently is considered responsible for the toxic effects of furan. The urinary metabolites of furan in rats are derived from the reaction of BDA with cellular nucleophiles, and precursors to these metabolites are detected in furan-exposed hepatocytes. Many of these precursors are 2-(S-glutathionyl)butanedial-amine cross-links in which the amines are amino acids and polyamines. Because these metabolites are derived from the reaction of BDA with cellular nucleophiles, their levels are a measure of the internal dose of this reactive metabolite. To compare the ability of human hepatocytes to convert furan to the same metabolites as rodent hepatocytes, furan was incubated with cryopreserved human and rodent hepatocytes. A semiquantitative liquid chromatography with tandem mass spectrometry assay was developed for a number of the previously characterized furan metabolites. Qualitative and semiquantitative analysis of the metabolites demonstrated that furan is metabolized in a similar manner in all three species. These results indicate that humans may be susceptible to the toxic effects of furan.
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Affiliation(s)
- Leah A Gates
- Division of Environmental Health Sciences (L.A.G., L.A.P.), Masonic Cancer Center (L.A.G., M.B.P., B.A.M., L.A.P.), and Department of Medicinal Chemistry (M.B.P., L.A.P.), University of Minnesota, Minneapolis, Minnesota
| | - Martin B Phillips
- Division of Environmental Health Sciences (L.A.G., L.A.P.), Masonic Cancer Center (L.A.G., M.B.P., B.A.M., L.A.P.), and Department of Medicinal Chemistry (M.B.P., L.A.P.), University of Minnesota, Minneapolis, Minnesota
| | - Brock A Matter
- Division of Environmental Health Sciences (L.A.G., L.A.P.), Masonic Cancer Center (L.A.G., M.B.P., B.A.M., L.A.P.), and Department of Medicinal Chemistry (M.B.P., L.A.P.), University of Minnesota, Minneapolis, Minnesota
| | - Lisa A Peterson
- Division of Environmental Health Sciences (L.A.G., L.A.P.), Masonic Cancer Center (L.A.G., M.B.P., B.A.M., L.A.P.), and Department of Medicinal Chemistry (M.B.P., L.A.P.), University of Minnesota, Minneapolis, Minnesota
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Yoon M, Efremenko A, Blaauboer BJ, Clewell HJ. Evaluation of simple in vitro to in vivo extrapolation approaches for environmental compounds. Toxicol In Vitro 2013; 28:164-70. [PMID: 24216301 DOI: 10.1016/j.tiv.2013.10.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/04/2013] [Accepted: 10/21/2013] [Indexed: 01/05/2023]
Abstract
As part of an effort to support in silico/in vitro based risk assessment, we evaluated the accuracy associated with conducting simple in vitro to in vivo extrapolation (IVIVE) for environmental compounds using available in vitro human metabolism data. The IVIVE approach was applied to a number of compounds with a wide range of properties spanning the diversity of characteristics of environmental compounds, and where possible the resulting estimates of the in vivo steady-state blood concentration were compared with estimates derived on the basis of human in vivo kinetic data. There appears to be a systematic bias in the estimation of intrinsic clearance (Clint) from in vitro versus in vivo data, with in vitro based estimates underestimating in vivo clearance for small values of Clint but with the opposite relationship at large values of Clint. Nevertheless, the resulting estimates of Css were in good agreement. The chief drawback of the simple approach used in this study, which performs the IVIVE prediction for the parent compound only, is that it is not applicable for toxicity associated with a metabolite.
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Affiliation(s)
- Miyoung Yoon
- The Hamner Institutes for Health Sciences, NC, USA.
| | | | - Bas J Blaauboer
- Institute for Risk Assessment Sciences, Division of Toxicology, University of Utrecht, NL, Netherlands
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Groothuis FA, Heringa MB, Nicol B, Hermens JLM, Blaauboer BJ, Kramer NI. Dose metric considerations in in vitro assays to improve quantitative in vitro-in vivo dose extrapolations. Toxicology 2013; 332:30-40. [PMID: 23978460 DOI: 10.1016/j.tox.2013.08.012] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 07/17/2013] [Accepted: 08/14/2013] [Indexed: 12/17/2022]
Abstract
Challenges to improve toxicological risk assessment to meet the demands of the EU chemical's legislation, REACH, and the EU 7th Amendment of the Cosmetics Directive have accelerated the development of non-animal based methods. Unfortunately, uncertainties remain surrounding the power of alternative methods such as in vitro assays to predict in vivo dose-response relationships, which impedes their use in regulatory toxicology. One issue reviewed here, is the lack of a well-defined dose metric for use in concentration-effect relationships obtained from in vitro cell assays. Traditionally, the nominal concentration has been used to define in vitro concentration-effect relationships. However, chemicals may differentially and non-specifically bind to medium constituents, well plate plastic and cells. They may also evaporate, degrade or be metabolized over the exposure period at different rates. Studies have shown that these processes may reduce the bioavailable and biologically effective dose of test chemicals in in vitro assays to levels far below their nominal concentration. This subsequently hampers the interpretation of in vitro data to predict and compare the true toxic potency of test chemicals. Therefore, this review discusses a number of dose metrics and their dependency on in vitro assay setup. Recommendations are given on when to consider alternative dose metrics instead of nominal concentrations, in order to reduce effect concentration variability between in vitro assays and between in vitro and in vivo assays in toxicology.
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Affiliation(s)
- Floris A Groothuis
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Minne B Heringa
- National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven, The Netherlands.
| | - Beate Nicol
- Unilever U.K., Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford MK44 1LQ, United Kingdom.
| | - Joop L M Hermens
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Bas J Blaauboer
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
| | - Nynke I Kramer
- Institute for Risk Assessment Sciences, Utrecht University, PO Box 80177, 3508 TD Utrecht, The Netherlands.
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Scholl G, Humblet MF, Scippo ML, De Pauw E, Eppe G, Saegerman C. Preliminary assessment of the risk linked to furan ingestion by babies consuming only ready-to-eat food. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 30:654-9. [DOI: 10.1080/19440049.2013.769137] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Abstract
Many xenobiotics containing a furan ring are toxic and/or carcinogenic. The harmful effects of these compounds require furan ring oxidation. This reaction generates an electrophilic intermediate. Depending on the furan ring substituents, the intermediate is either an epoxide or a cis-enedione with more ring substitution favoring epoxide formation. Either intermediate reacts with cellular nucleophiles such as protein or DNA to trigger toxicities. The reactivity of the metabolite determines which cellular nucleophiles are targeted. The toxicity of a particular furan is also influenced by the presence of competing metabolic pathways or efficient detoxification routes. GSH plays an important role in modulating the harmful effects of this class of compound by reacting with the reactive metabolite. However, this may not represent a detoxification step in all cases.
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Affiliation(s)
- Lisa A Peterson
- Division of Environmental Health Sciences, and Masonic Cancer Center, University of Minnesota , Minneapolis, Minnesota 55455, United States
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Shuler ML, Ghanem A, Quick D, Wong MC, Miller P. A self-regulating cell culture analog device to mimic animal and human toxicological responses. Biotechnol Bioeng 2012; 52:45-60. [PMID: 18629851 DOI: 10.1002/(sici)1097-0290(19961005)52:1<45::aid-bit5>3.0.co;2-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The overall goal of this project is the development of a new methodology for translating advances in molecular level understanding of toxicological responses into a predictive tool for dose response in whole animals and humans exposed to single compounds or mixtures of compounds. The methodology incorporates a mechanistic cellular level model into a PBPK (physiologically based pharmacokinetic) model which simultaneously guides the development of an in vitro cell culture analog (CCA) to the PBPK. Where the PBPK specifies an organ, (e.g., liver) the in vitro or CCA system contains a compartment with the appropriate cell or cell population (e.g., hepatocytes for the liver). The CCA has significant advantages over other in vitro systems and PBPK systems used independently for evaluating metabolic responses to drugs or potentially toxic chemicals where the exchange of metabolites between organs is likely to be important. The CCA system is superior to a PBPK because an a priori description of complete metabolism is not required and secondary, unexpected interactions can be detected. The CCA system, unlike other in vitro systems, gives a dynamic response that realistically simulates in vivo interactions between organs. Furthermore, the CCA allows dosing on the same basis as animal tests (e.g., milligrams per kilogram of body mass equivalent). Because the construction of a CCA is guided by a PBPK, this approach allows extrapolation to low doses and across species, including extrapolation to humans. We have constructed a prototype system and have conducted proof-of-concept experiments using naphthalene as a test chemical. These experiments clearly demonstrate the ability to generate a reactive metabolite in one compartment and detect its effects (on LDH release and glutathione depletion) in a second compartment. However, this prototype device would be expensive to replicate and requires nearly constant supervision from a trained investigator. For this concept to replace animals an inexpensive, self-regulating device is needed. An initial design to accomplish this goal is described as well as the corresponding model using naphthalene as a test compound. (c) 1996 John Wiley & Sons, Inc.
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Affiliation(s)
- M L Shuler
- School of Chemical Engineering, Cornell University, Ithaca, New York 14853-5201
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Lengler I, Buhrke T, Scharmach E, Lampen A. In-vitro toxicological and proteomic analysis of furan fatty acids which are oxidative metabolites of conjugated linoleic acids. Lipids 2012; 47:1085-97. [PMID: 22949068 DOI: 10.1007/s11745-012-3713-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 08/17/2012] [Indexed: 12/31/2022]
Abstract
Furan fatty acids (furan-FA) are oxidative products of conjugated linoleic acids (CLA) and may therefore be ingested when CLA-containing food or food-additives are consumed. Due to the presence of a furan ring structure the question arises whether furan-FA may have toxic properties on enterocytes and liver cells. Here we show that furan-FA neither have toxic effects in human colon cancer cell line Caco-2 nor in human hepatoma cell line HepG2 at concentrations that could be relevant for humans. At concentrations up to 100 μM, all tested furan-FA isomers showed no pronounced cytotoxicity and did not affect cellular proliferation or apoptosis up to concentrations of 500 μM. In addition, furan-FA was neither genotoxic in the micronucleus test using Chinese hamster lung fibroblasts (V79) nor in the Ames test independent of the presence or absence of rat liver homogenate for enzymatic activation of the furan ring structure. A proteomic approach revealed that 48 proteins were differentially expressed when Caco-2 cells were incubated with up to 1 mM of 10,13-epoxy-10,12-octadecadienoic acid (10,12-furan-FA). Three of the 30 proteins that could be identified by MALDI-TOF analysis were upregulated and were associated with lipid droplet biogenesis. The remaining 27 proteins were downregulated and were considered to be associated with general cellular processes such as DNA replication and transcription, protein biosynthesis and protein processing, lipid and energy metabolism. From the proteomic data we conclude that furan-FA is predominantly stored in lipid droplets thereby downregulating cellular metabolic activity and driving the cells into a state of rest.
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Affiliation(s)
- Imme Lengler
- Department of Food Safety, Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
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Scholl G, Huybrechts I, Humblet MF, Scippo ML, De Pauw E, Eppe G, Saegerman C. Risk assessment for furan contamination through the food chain in Belgian children. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2012; 29:1219-29. [DOI: 10.1080/19440049.2012.686456] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Yoon M, Campbell JL, Andersen ME, Clewell HJ. Quantitativein vitrotoin vivoextrapolation of cell-based toxicity assay results. Crit Rev Toxicol 2012; 42:633-52. [DOI: 10.3109/10408444.2012.692115] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Moro S, Chipman JK, Wegener JW, Hamberger C, Dekant W, Mally A. Furan in heat-treated foods: formation, exposure, toxicity, and aspects of risk assessment. Mol Nutr Food Res 2012; 56:1197-211. [PMID: 22641279 DOI: 10.1002/mnfr.201200093] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/26/2012] [Accepted: 04/04/2012] [Indexed: 12/24/2022]
Abstract
Furan is formed in a variety of heat-treated foods through thermal degradation of natural food constituents. Relatively high levels of furan contamination are found in ground roasted coffee, instant coffee, and processed baby foods. European exposure estimates suggest that mean dietary exposure to furan may be as high as 1.23 and 1.01 μg/kg bw/day for adults and 3- to 12-month-old infants, respectively. Furan is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥ 2 mg/kg bw. There is therefore a relatively low margin of exposure between estimated human exposure and doses that cause a high tumor incidence in rodents. Since a genotoxic mode of action cannot be excluded for furan-induced tumor formation, the present exposures may indicate a risk to human health and need for mitigation. This review summarizes the current knowledge on mechanisms of furan formation in food, human dietary exposure to furan, and furan toxicity, and highlights the need to establish the risk resulting from the genotoxic and carcinogenic properties of furan at doses lower than 2 mg/kg bw.
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Affiliation(s)
- Sabrina Moro
- Department of Toxicology, University of Würzburg, Würzburg, Germany
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Gates LA, Lu D, Peterson LA. Trapping of cis-2-butene-1,4-dial to measure furan metabolism in human liver microsomes by cytochrome P450 enzymes. Drug Metab Dispos 2012; 40:596-601. [PMID: 22187484 PMCID: PMC3286269 DOI: 10.1124/dmd.111.043679] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/20/2011] [Indexed: 11/22/2022] Open
Abstract
Furan is a liver toxicant and carcinogen in rodents. It is classified as a possible human carcinogen, but the human health effects of furan exposure remain unknown. The oxidation of furan by cytochrome P450 (P450) enzymes is necessary for furan toxicity. The product of this reaction is the reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). To determine whether human liver microsomes metabolize furan to BDA, a liquid chromatography/tandem mass spectrometry method was developed to detect and quantify BDA by trapping this reactive metabolite with N-acetyl-l-cysteine (NAC) and N-acetyl-l-lysine (NAL). Reaction of NAC and NAL with BDA generates N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine (NAC-BDA-NAL). Formation of NAC-BDA-NAL was quantified in 21 different human liver microsomal preparations. The levels of metabolism were comparable to that observed in F-344 rat and B6C3F1 mouse liver microsomes, two species known to be sensitive to furan-induced toxicity. Studies with recombinant human liver P450s indicated that CYP2E1 is the most active human liver furan oxidase. The activity of CYP2E1 as measured by p-nitrophenol hydroxylase activity was correlated to the extent of NAC-BDA-NAL formation in human liver microsomes. The formation of NAC-BDA-NAL was blocked by CYP2E1 inhibitors but not other P450 inhibitors. These results suggest that humans are capable of oxidizing furan to its toxic metabolite, BDA, at rates comparable to those of species sensitive to furan exposure. Therefore, humans may be susceptible to furan's toxic effects.
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Affiliation(s)
- Leah A Gates
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA
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McDaniel LP, Ding W, Dobrovolsky VN, Shaddock JG, Mittelstaedt RA, Doerge DR, Heflich RH. Genotoxicity of furan in Big Blue rats. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2012; 742:72-8. [DOI: 10.1016/j.mrgentox.2011.12.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 12/09/2011] [Accepted: 12/10/2011] [Indexed: 01/01/2023]
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Buhrke T, Merkel R, Lengler I, Lampen A. Absorption and metabolism of cis-9,trans-11-CLA and of its oxidation product 9,11-furan fatty acid by Caco-2 cells. Lipids 2012; 47:435-42. [PMID: 22249938 PMCID: PMC3311842 DOI: 10.1007/s11745-012-3653-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 12/22/2011] [Indexed: 11/24/2022]
Abstract
Furan fatty acids (furan-FA) can be formed by auto-oxidation of conjugated linoleic acids (CLA) and may therefore be ingested when CLA-containing foodstuff is consumed. Due to the presence of a furan ring structure, furan-FA may have toxic properties, however, these substances are toxicologically not well characterized so far. Here we show that 9,11-furan-FA, the oxidation product of the major CLA isomer cis-9,trans-11-CLA (c9,t11-CLA), is not toxic to human intestinal Caco-2 cells up to a level of 100 μM. Oil-Red-O staining indicated that 9,11-furan-FA as well as c9,t11-CLA and linoleic acid are taken up by the cells and stored in the form of triglycerides in lipid droplets. Chemical analysis of total cellular lipids revealed that 9,11-furan-FA is partially elongated probably by the enzymatic activity of cellular fatty acid elongases whereas c9,t11-CLA is partially converted to other isomers such as c9,c11-CLA or t9,t11-CLA. In the case of 9,11-furan-FA, there is no indication for any modification or activation of the furan ring system. From these results, we conclude that 9,11-furan-FA has no properties of toxicological relevance at least for Caco-2 cells which serve as a model for enterocytes of the human small intestine.
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Affiliation(s)
- Thorsten Buhrke
- Department of Food Safety, Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany.
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Scholl G, Humblet MF, Scippo ML, De Pauw E, Eppe G, Saegerman C. Risk assessment of Belgian adults for furan contamination through the food chain. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2011; 29:345-53. [PMID: 22168174 DOI: 10.1080/19440049.2011.637240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Risk assessment is an interdisciplinary process used to quantify the risk linked to a hazard. In the present paper it is applied to quantify the risk linked to furan ingestion through the food chain for the Belgian adult population. Two approaches, deterministic and probabilistic, were carried out in parallel. The deterministic method relied on a case study, whereas the probabilistic approach involved statistical distributions of contamination and consumption data to calculate a statistical distribution of the daily intake. First, the deterministic method revealed a low estimated daily intake (EDI) for the average population (380 ng*(kg(bw)*day)⁻¹) and a huge contribution of coffee consumption to the EDI (55%). Increasing or decreasing the daily coffee consumption by one cup can affect the EDI by about 22%. Afterwards, the probabilistic approach showed that the average population has a low EDI (494 ng*(kg(bw)*day)⁻¹), and that high contamination levels were only registered in a small proportion of the population. Finally, a comparison of the RfD(chronic oral) showed that less than 10% of the Belgian population had an EDI above the reference dose proposed by the USEPA; the majority of the population had an EDI 20% below the reference dose. The margin of exposure (MoE) approach indicated that the level of risk related to furan intake through ingestion is low, with a MoE > 10,000 for more than 10% of the population and no result < 100.
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Affiliation(s)
- G Scholl
- Research Unit in Epidemiology and Risk Analysis Applied to Veterinary Sciences (UREAR), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
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Hamberger C, Kellert M, Schauer UM, Dekant W, Mally A. Hepatobiliary toxicity of furan: identification of furan metabolites in bile of male f344/n rats. Drug Metab Dispos 2010; 38:1698-706. [PMID: 20639435 DOI: 10.1124/dmd.109.031781] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Furan, which occurs in a wide variety of heat-treated foods, is a potent hepatotoxicant and liver carcinogen in rodents. In a 2-year bioassay, furan caused hepatocellular adenomas and carcinomas in mice and rats but also high incidences of bile duct tumors in rats. Furan is bioactivated by cytochrome P450 enzymes to cis-2-butene-1,4-dial, an α,β-unsaturated dialdehyde, which readily reacts with tissue nucleophiles. The objective of this study was to structurally characterize furan metabolites excreted with bile to better understand the potential role of reactive furan intermediates in the biliary toxicity of furan. Bile duct-cannulated F344/N rats (n = 3) were administered a single oral dose of 5 mg/kg b.wt. [(12)C(4)]furan or stable isotope-labeled [3,4-(13)C]furan, and bile samples collected at 30-min intervals for 4 h were analyzed by liquid chromatography-tandem mass spectrometry. A total of eight furan metabolites derived from reaction of cis-2-butene-1,4-dial with GSH and/or amino acids and subsequent enzymatic degradation were detected in bile. The main metabolite was a cyclic monoglutathione conjugate of cis-2-butene-1,4-dial, which was previously detected in urine of furan-treated rats. Furthermore, a N-acetylcysteine-N-acetyllysine conjugate, previously observed in rat urine, and a cysteinylglycine-glutathione conjugate were identified as major metabolites. These data suggest that degraded protein adducts are in vivo metabolites of furan, consistent with the hypothesis that cytotoxicity mediated through binding of cis-2-butene-1,4-dial to critical target proteins is likely to play a key role in furan toxicity and carcinogenicity.
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Poet TS, Wu H, Corley RA, Thrall KD. In vitro glutathione conjugation of methyl iodide in rat, rabbit, and human blood and tissues. Inhal Toxicol 2010; 21:524-30. [PMID: 19519152 DOI: 10.1080/08958370802598203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Methyl iodide (MeI) is an intermediate in the manufacture of some pesticides and pharmaceuticals, and is under review for US registration as a non-ozone depleting alternative for methyl bromide for pre-plant soil fumigation. MeI is primarily metabolized via conjugation with glutathione (GSH), with further metabolism to S-methyl cysteine and methanethiol. To facilitate extrapolations of animal pharmacokinetic data to humans, rate constants for the GSH metabolism of MeI were determined in cytosols prepared from the liver and kidneys of rats, human donors, female rabbits, and rabbit fetuses, from rabbit olfactory and respiratory epithelium, and from rabbit and rat blood using a headspace vial equilibration technique and two-compartment mathematical model. MeI was metabolized in liver and kidney from adults of all three species, but metabolism was not detectable in fetal rabbit kidney. Maximal metabolic rates (V(max)) were similar in liver from rat and human donors (approximately 40 and 47 nmol/min/mg, respectively) whereas the V(max) rates in kidney cytosols varied approximately three-fold between the three species. No difference was observed in the loss of MeI from active and inactive whole blood from either rats or rabbits. The metabolism in olfactory and respiratory epithelial cytosol had Michaelis-Menten constant (K(m)) values that were several times higher than for any other tissue, suggesting essentially first-order metabolism in the nose. The metabolism of MeI in human liver cytosol prepared from five individual donors indicated two potential populations, one high affinity/low capacity and one with a lower affinity but higher capacity.
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Affiliation(s)
- Torka S Poet
- Battelle, Pacific Northwest Division, Richland, Washington 99352, USA.
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Toxicity and carcinogenicity of furan in human diet. Arch Toxicol 2010; 84:563-78. [DOI: 10.1007/s00204-010-0531-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 02/22/2010] [Indexed: 01/31/2023]
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Lu D, Peterson LA. Identification of furan metabolites derived from cysteine-cis-2-butene-1,4-dial-lysine cross-links. Chem Res Toxicol 2010; 23:142-51. [PMID: 20043645 PMCID: PMC2826838 DOI: 10.1021/tx9003215] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Furan is a rodent hepatotoxicant and carcinogen. Because this compound is an important industrial intermediate and has been detected in heat-processed foods and smoke, humans are likely exposed to this toxic compound. Characterization of urinary metabolites of furan will lead to the development of biomarkers to assess human health risks associated with furan exposure. Previous studies indicate that furan is oxidized to a reactive alpha,beta-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA), in a reaction catalyzed by cytochrome P450. Five previously characterized metabolites are derived from the reaction of BDA with cellular nucleophiles such as glutathione and protein. They include the monoglutathione reaction product, N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-l-cysteinylglycine cyclic sulfide, and its downstream metabolite, S-[1-(1,3-dicarboxypropyl)-1H-pyrrol-3-yl]methylthiol, as well as (R)-2-acetylamino-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid and N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine and its sulfoxide. The last two compounds are downstream metabolites of a BDA-derived cysteine-lysine cross-link, S-[1-(5-amino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine. In this report, we present the characterization of seven additional urinary furan metabolites, all of which are derived from this cross-link. The cysteinyl residue is subject to several biotransformation reactions, including N-acetylation and S-oxidation. Alternatively, it can undergo beta-elimination followed by S-methylation to a methylthiol intermediate that is further oxidized to a sulfoxide. The lysine portion of the cross-link either is N-acetylated or undergoes a transamination reaction to generate an alpha-ketoacid metabolite that undergoes oxidative decarboxylation. Some of these metabolites are among the most abundant furan metabolites present in urine as judged by LC-MS/MS analysis, indicating that the oxidation of furan to BDA and BDA's subsequent reaction with cellular cysteine and lysine residues may represent a significant in vivo pathway of furan biotransformation. Because they are derived from cellular BDA reaction products, these metabolites are markers of furan exposure and bioactivation and could be explored as potential biomarkers in human studies.
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Affiliation(s)
- Ding Lu
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | - Lisa A. Peterson
- Division of Environmental Health Sciences and Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
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Lu D, Sullivan MM, Phillips MB, Peterson LA. Degraded protein adducts of cis-2-butene-1,4-dial are urinary and hepatocyte metabolites of furan. Chem Res Toxicol 2009; 22:997-1007. [PMID: 19441776 PMCID: PMC2696637 DOI: 10.1021/tx800377v] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Furan is a liver toxicant and carcinogen in rodents. On the basis of these observations and the large potential for human exposure, furan has been classified as a possible human carcinogen. The mechanism of tumor induction by furan is unknown. However, the toxicity requires cytochrome P450-catalyzed oxidation of furan. The product of this oxidation, cis-2-butene-1,4-dial (BDA), reacts readily with glutathione, amino acids, and DNA and is a bacterial mutagen in Ames assay strain TA104. Characterization of the urinary metabolites of furan is expected to provide information regarding the structure(s) of the reactive metabolite(s). Recently, several urinary metabolites have been identified. We reported the presence of a monoglutathione-BDA reaction product, N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-l-cysteinylglycine cyclic sulfide. Three additional urinary metabolites of furan were also characterized as follows: R-2-acetylamino-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid, N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine, and its sulfoxide. It was postulated that these three metabolites are derived from degraded protein adducts. However, the possibility that these metabolites result from the reaction of BDA with free lysine and/or cysteine was not ruled out. In this latter case, one might predict that the reaction of thiol-BDA with free lysine would not occur exclusively on the epsilon-amino group. Reaction of BDA with N-acetylcysteine or GSH in the presence of lysine indicated that both the alpha- and the epsilon-amino groups of lysine can be modified by thiol-BDA. The N-acetylcysteine-BDA-N-acetyllysine urinary metabolites were solely linked through the epsilon-amino group of lysine. A GSH-BDA-lysine cross-link was a significant hepatocyte metabolite of furan. In this case, the major product resulted from reaction with the epsilon-amino group of lysine; however, small amounts of the alpha-amino reaction product were also observed. Western analysis of liver and hepatocyte protein extracts using anti-GSH antibody indicated that GSH was covalently linked to proteins in tissues or cells exposed to furan. Our data support the hypothesis that GSH-BDA can react with either free lysine or protein lysine groups. These data suggest that there are multiple pathways by which furan can modify cellular nucleophiles. In one pathway, BDA reacts directly with proteins to form cysteine-lysine reaction products. In another, BDA reacts with GSH to form GSH-BDA conjugates, which then react with cellular nucleophiles like free lysine or lysine moieties in proteins. Both pathways will give rise to N-acetyl-S-[1-(5-acetylamino-5-carboxypentyl)-1H-pyrrol-3-yl]-l-cysteine. Given the abundance of these metabolites in urine of furan-treated rats, these pathways appear to be major pathways of furan biotransformation in vivo.
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Affiliation(s)
- Ding Lu
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
| | | | - Martin B. Phillips
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455
| | - Lisa A. Peterson
- Division of Environmental Health Sciences, University of Minnesota, Minneapolis, MN 55455
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
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Abstract
The industrial and environmental chemical, furan, is a liver toxicant and carcinogen in laboratory animals. It has been classified as a possible human carcinogen. The mechanism of tumor induction is unknown. However, toxicity is initiated by cytochrome P450 catalyzed oxidation of furan to an alpha,beta-unsaturated dialdehyde, cis-2-butene-1,4-dial. This metabolite reacts readily with protein and DNA nucleophiles and is a bacterial mutagen in Ames assay strain TA104. Metabolism studies indicate that this reactive metabolite is formed in vivo. It is also an intermediate leading to other metabolites whose role in furan-derived toxicities has yet to be explored.
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Affiliation(s)
- Lisa A Peterson
- Division of Environmental Health Sciences and the Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA.
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Brown CM, Reisfeld B, Mayeno AN. Cytochromes P450: A Structure-Based Summary of Biotransformations Using Representative Substrates. Drug Metab Rev 2008. [DOI: 10.1080/03602530701836662] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Lipscomb JC, Meek ME(B, Krishnan K, Kedderis GL, Clewell H, Haber L. Incorporation of Pharmacokinetic and Pharmacodynamic Data into Risk Assessments. Toxicol Mech Methods 2008; 14:145-58. [DOI: 10.1080/15376520490429382] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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48
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Lipscomb JC, Poet TS. In vitro measurements of metabolism for application in pharmacokinetic modeling. Pharmacol Ther 2008; 118:82-103. [DOI: 10.1016/j.pharmthera.2008.01.006] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 01/24/2008] [Indexed: 11/25/2022]
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Kellert M, Wagner S, Lutz U, Lutz WK. Biomarkers of Furan Exposure by Metabolic Profiling of Rat Urine with Liquid Chromatography-Tandem Mass Spectrometry and Principal Component Analysis. Chem Res Toxicol 2008; 21:761-8. [DOI: 10.1021/tx7004212] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marco Kellert
- Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Silvia Wagner
- Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Ursula Lutz
- Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Werner K. Lutz
- Department of Toxicology, University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
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Kulkarni SA, Moir D, Zhu J. Influence of structural and functional modifications of selected genotoxic carcinogens on metabolism and mutagenicity - a review. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2007; 18:459-514. [PMID: 17654335 DOI: 10.1080/10629360701430090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Alterations in molecular structure are responsible for the differential biological response(s) of a chemical inside a biosystem. Structural and functional parameters that govern a chemical's metabolic course and determine its ultimate outcome in terms of mutagenic/carcinogenic potential are extensively reviewed here. A large number of environmentally-significant organic chemicals are addressed under one or more broadly classified groups each representing one or more characteristic structural feature. Numerous examples are cited to illustrate the influence of key structural and functional parameters on the metabolism and DNA adduction properties of different chemicals. It is hoped that, in the event of limited experimental data on a chemical's bioactivity, such knowledge of the likely roles played by key molecular features should provide preliminary information regarding its bioactivation, detoxification and/or mutagenic potential and aid the process of screening and prioritising chemicals for further testing.
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Affiliation(s)
- S A Kulkarni
- Chemistry Research Division, Safe Environments Programme, Health Canada, AL: 0800C, Ottawa, Ontario, K1A 0L2, Canada
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