1
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Cohen SM. Cell proliferation and carcinogenesis: an approach to screening for potential human carcinogens. Front Oncol 2024; 14:1394584. [PMID: 38868530 PMCID: PMC11168196 DOI: 10.3389/fonc.2024.1394584] [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: 03/01/2024] [Accepted: 04/22/2024] [Indexed: 06/14/2024] Open
Abstract
Cancer arises from multiple genetic errors occurring in a single stem cell (clonality). Every time DNA replicates, mistakes occur. Thus, agents can increase the risk of cancer either by directly damaging DNA (DNA-reactive carcinogens) or increasing the number of DNA replications (increased cell proliferation). Increased cell proliferation can be achieved either by direct mitogenesis or cytotoxicity with regenerative proliferation. Human carcinogens have a mode of action of DNA reactivity, immunomodulation (mostly immunosuppression), increased estrogenic activity (mitogenesis), or cytotoxicity and regeneration. By focusing on screening for these four effects utilizing in silico, in vitro, and short-term in vivo assays, a biologically based screening for human chemical carcinogens can be accomplished with greater predictivity than the traditional 2-year bioassay with considerably less cost, less time, and the use of fewer animals.
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Affiliation(s)
- Samuel M. Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology, Microbiology, and Immunology and the Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States
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2
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Guth S, Baum M, Cartus AT, Diel P, Engel KH, Engeli B, Epe B, Grune T, Haller D, Heinz V, Hellwig M, Hengstler JG, Henle T, Humpf HU, Jäger H, Joost HG, Kulling SE, Lachenmeier DW, Lampen A, Leist M, Mally A, Marko D, Nöthlings U, Röhrdanz E, Roth A, Spranger J, Stadler R, Steinberg P, Vieths S, Wätjen W, Eisenbrand G. Evaluation of the genotoxic potential of acrylamide: Arguments for the derivation of a tolerable daily intake (TDI value). Food Chem Toxicol 2023; 173:113632. [PMID: 36708862 DOI: 10.1016/j.fct.2023.113632] [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: 12/21/2021] [Revised: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
This opinion of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) presents arguments for an updated risk assessment of diet-related exposure to acrylamide (AA), based on a critical review of scientific evidence relevant to low dose exposure. The SKLM arrives at the conclusion that as long as an appropriate exposure limit for AA is not exceeded, genotoxic effects resulting in carcinogenicity are unlikely to occur. Based on the totality of the evidence, the SKLM considers it scientifically justified to derive a tolerable daily intake (TDI) as a health-based guidance value.
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Affiliation(s)
- Sabine Guth
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystr. 67, 44139, Dortmund, Germany.
| | - Matthias Baum
- Solenis Germany Industries GmbH, Fütingsweg 20, 47805 Krefeld, Germany.
| | | | - Patrick Diel
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933, Cologne, Germany.
| | - Karl-Heinz Engel
- Technical University of Munich, Maximus-von-Imhof-Forum 2, 85354, Freising, Germany.
| | - Barbara Engeli
- Federal Food Safety and Veterinary Office (FSVO), Risk Assessment Division, Schwarzenburgstrasse 155, 3003, Bern, Switzerland.
| | - Bernd Epe
- Institute of Pharmaceutical and Biomedical Sciences, University of Mainz, Staudinger Weg 5, 55128, Mainz, Germany.
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition (DIfE), Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany.
| | - Dirk Haller
- ZIEL - Institute for Food & Health, Technical University of Munich, 85354, Freising, Germany; Technical University of Munich, Gregor-Mendel-Str. 2, 85354, Freising, Germany.
| | - Volker Heinz
- German Institute of Food Technologies (DIL), Prof.-von-Klitzing-Str. 7, 49610, Quakenbrück, Germany.
| | - Michael Hellwig
- Technische Universität Dresden, Bergstraße 66, 01062, Dresden, Germany.
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystr. 67, 44139, Dortmund, Germany.
| | - Thomas Henle
- Department of Food Chemistry, TU Dresden, Bergstrasse 66, 01062, Dresden, Germany.
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 45, 48149, Münster, Germany.
| | - Henry Jäger
- Institute of Food Technology, University of Natural Resources and Life Sciences (BOKU), Muthgasse 18, 1190, Vienna, Austria.
| | - Hans-Georg Joost
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany.
| | - Sabine E Kulling
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Straße 9, 76131, Karlsruhe, Germany.
| | - Dirk W Lachenmeier
- Chemisches und Veterinäruntersuchungsamt Karlsruhe, Weißenburger Str. 3, 76187, Karlsruhe, Germany.
| | - Alfonso Lampen
- University of Veterinary Medicine Hannover, Institute for Food Quality and Food Safety, Bischofsholer Damm 15, 30173, Hannover, Germany.
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, Department Inaugurated By the Doerenkamp-Zbinden Foundation, University of Konstanz, Box 657, 78457, Konstanz, Germany.
| | - Angela Mally
- Department of Toxicology, University of Würzburg, Versbacher Str. 9, 97078, Würzburg, Germany.
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Straße 38, 1090, Vienna, Austria.
| | - Ute Nöthlings
- Department of Nutrition and Food Sciences, Nutritional Epidemiology, Rheinische Friedrich-Wilhelms University Bonn, Friedrich-Hirzebruch-Allee 7, 53115, Bonn, Germany.
| | - Elke Röhrdanz
- Unit Reproductive and Genetic Toxicology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger Allee 3, 53175, Bonn, Germany.
| | - Angelika Roth
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), Ardeystr. 67, 44139, Dortmund, Germany.
| | - Joachim Spranger
- Department of Endocrinology and Metabolic Medicine, Campus Benjamin Franklin, Charité University Medicine, Hindenburgdamm 30, 12200, Berlin, Germany.
| | - Richard Stadler
- Institute of Food Safety and Analytical Sciences, Nestlé Research Centre, Route du Jorat 57, 1000, Lausanne, 26, Switzerland.
| | - Pablo Steinberg
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Haid-und-Neu-Str. 9, 76131, Karlsruhe, Germany.
| | - Stefan Vieths
- Paul-Ehrlich-Institut, Paul-Ehrlich-Straße 51-59, 63225, Langen, Germany.
| | - Wim Wätjen
- Institut für Agrar- und Ernährungswissenschaften, Martin-Luther-Universität Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany.
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3
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Davidsen JM, Cohen SM, Eisenbrand G, Fukushima S, Gooderham NJ, Guengerich FP, Hecht SS, Rietjens IMCM, Rosol TJ, Harman CL, Taylor SV. FEMA GRAS assessment of derivatives of basil, nutmeg, parsley, tarragon and related allylalkoxybenzene-containing natural flavor complexes. Food Chem Toxicol 2023; 175:113646. [PMID: 36804339 DOI: 10.1016/j.fct.2023.113646] [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: 11/22/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/18/2023]
Abstract
In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a program for the re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavoring ingredients in food. In this publication, tenth in the series, NFCs containing a high percentage of at least one naturally occurring allylalkoxybenzene constituent with a suspected concern for genotoxicity and/or carcinogenicity are evaluated. In a related paper, ninth in the series, NFCs containing anethole and/or eugenol and relatively low percentages of these allylalkoxybenzenes are evaluated. The Panel applies the threshold of toxicological concern (TTC) concept and evaluates relevant toxicology data on the NFCs and their respective constituent congeneric groups. For NFCs containing allylalkoxybenzene constituent(s), the estimated intake of the constituent is compared to the TTC for compounds with structural alerts for genotoxicity and when exceeded, a margin of exposure (MOE) is calculated. BMDL10 values are derived from benchmark dose analyses using Bayesian model averaging for safrole, estragole and methyl eugenol using EPA's BMDS software version 3.2. BMDL10 values for myristicin, elemicin and parsley apiole were estimated by read-across using relative potency factors. Margins of safety for each constituent congeneric group and MOEs for each allylalkoxybenzene constituent for each NFC were determined that indicate no safety concern. The scope of the safety evaluation contained herein does not include added use in dietary supplements or any products other than food. Ten NFCs, derived from basil, estragon (tarragon), mace, nutmeg, parsley and Canadian snakeroot were determined or affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavor ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.
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Affiliation(s)
- Jeanne M Davidsen
- Flavor and Extract Manufacturers Association, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Dept. of Pathology and Microbiology, University of Nebraska Medical Center, 983135 Nebraska Medical Center, Omaha, NE, 68198-3135, USA
| | - Gerhard Eisenbrand
- University of Kaiserslautern, Germany (Retired), Kühler Grund 48/1, 69126, Heidelberg, Germany
| | - Shoji Fukushima
- Japan Bioassay Research Center, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Nigel J Gooderham
- Dept. of Metabolism, Digestion, Reproduction, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, United Kingdom
| | - F Peter Guengerich
- Dept. of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Dept. of Laboratory Medicine and Pathology, Cancer and Cardiovascular Research Building, 2231 6th St, S.E, Minneapolis, MN, 55455, USA
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 6708 WE, Wageningen, the Netherlands
| | - Thomas J Rosol
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, 1 Ohio University, Athens, OH, 45701, USA
| | - Christie L Harman
- Flavor and Extract Manufacturers Association, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA
| | - Sean V Taylor
- Scientific Secretary to the FEMA Expert Panel, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA.
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4
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Röhl C, Batke M, Damm G, Freyberger A, Gebel T, Gundert-Remy U, Hengstler JG, Mangerich A, Matthiessen A, Partosch F, Schupp T, Wollin KM, Foth H. New aspects in deriving health-based guidance values for bromate in swimming pool water. Arch Toxicol 2022; 96:1623-1659. [PMID: 35386057 PMCID: PMC9095538 DOI: 10.1007/s00204-022-03255-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 02/17/2022] [Indexed: 11/27/2022]
Abstract
Bromate, classified as a EU CLP 1B carcinogen, is a typical by-product of the disinfection of drinking and swimming pool water. The aim of this study was (a) to provide data on the occurrence of bromate in pool water, (b) to re-evaluate the carcinogenic MOA of bromate in the light of existing data, (c) to assess the possible exposure to bromate via swimming pool water and (d) to inform the derivation of cancer risk-related bromate concentrations in swimming pool water. Measurements from monitoring analysis of 229 samples showed bromate concentrations in seawater pools up to 34 mg/L. A comprehensive non-systematic literature search was done and the quality of the studies on genotoxicity and carcinogenicity was assessed by Klimisch criteria (Klimisch et al., Regul Toxicol Pharmacol 25:1–5, 1997) and SciRAP tool (Beronius et al., J Appl Toxicol, 38:1460–1470, 2018) respectively. Benchmark dose (BMD) modeling was performed using the modeling average mode in BMDS 3.1 and PROAST 66.40, 67 and 69 (human cancer BMDL10; EFSA 2017). For exposure assessment, data from a wide range of sources were evaluated for their reliability. Different target groups (infants/toddlers, children and adults) and exposure scenarios (recreational, sport-active swimmers, top athletes) were considered for oral, inhalation and dermal exposure. Exposure was calculated according to the frequency of swimming events and duration in water. For illustration, cancer risk-related bromate concentrations in pool water were calculated for different target groups, taking into account their exposure using the hBMDL10 and a cancer risk of 1 in 100,000. Convincing evidence was obtained from a multitude of studies that bromate induces oxidative DNA damage and acts as a clastogen in vitro and in vivo. Since statistical modeling of the available genotoxicity data is compatible with both linear as well as non-linear dose–response relationships, bromate should be conservatively considered to be a non-threshold carcinogen. BMD modeling with model averaging for renal cancer studies (Kurokawa et al., J Natl. Cancer Inst, 1983 and 1986a; DeAngelo et al., Toxicol Pathol 26:587–594, 1998) resulted in a median hBMDL10 of 0.65 mg bromate/kg body weight (bw) per day. Evaluation of different age and activity groups revealed that top athletes had the highest exposure, followed by sport-active children, sport-active adults, infants and toddlers, children and adults. The predominant route of exposure was oral (73–98%) by swallowing water, followed by the dermal route (2–27%), while the inhalation route was insignificant (< 0.5%). Accepting the same risk level for all population groups resulted in different guidance values due to the large variation in exposure. For example, for an additional risk of 1 in 100,000, the bromate concentrations would range between 0.011 for top athletes, 0.015 for sport-active children and 2.1 mg/L for adults. In conclusion, the present study shows that health risks due to bromate exposure by swimming pool water cannot be excluded and that large differences in risk exist depending on the individual swimming habits and water concentrations.
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Affiliation(s)
- C Röhl
- Institute of Toxicology and Pharmacology for Natural Scientists, Christiana Albertina University Kiel, Kiel, Germany. .,Department of Environmental Health Protection, State Agency for social Services (LAsD) Schleswig-Holstein, Neumünster, Germany.
| | - M Batke
- University Emden/Leer, Emden, Germany
| | - G Damm
- Department of Hepatobiliary Surgery and Visceral Transplantation, University Hospital, Leipzig University, Leipzig, Germany
| | - A Freyberger
- Research and Development, Pharmaceuticals, RED-PCD-TOX-P&PC Clinical Pathology, Bayer AG, Wuppertal, Germany
| | - T Gebel
- Federal Institute for Occupational Safety and Health (BAuA), Dortmund, Germany
| | - U Gundert-Remy
- Institute for Clinical Pharmacology and Toxicology, Universitätsmedizin Berlin, Charité Berlin, Germany
| | - J G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors (IfADo), TU Dortmund University, Dortmund, Germany
| | - A Mangerich
- Molecular Toxicology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - A Matthiessen
- Central Unit for Environmental Hygiene, University Hospital Schleswig-Holstein (UKSH), Kiel, Germany
| | - F Partosch
- Department of Toxicology, Fraunhofer-Institute for Toxicology and Experimental Medicine (ITEM), Hannover, Germany
| | - T Schupp
- Department of Chemical Engineering, University of Applied Science Muenster, Steinfurt, Germany
| | - K M Wollin
- Formerly Public Health Agency of Lower Saxony, Hannover, Germany
| | - H Foth
- Institute of Environmental Toxicology, University of Halle, Halle/Saale, Germany
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5
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Cooper TK, Meyerholz DK, Beck AP, Delaney MA, Piersigilli A, Southard TL, Brayton CF. Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits. ILAR J 2022; 62:77-132. [PMID: 34979559 DOI: 10.1093/ilar/ilab022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/12/2021] [Indexed: 12/31/2022] Open
Abstract
Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.
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Affiliation(s)
- Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Amanda P Beck
- Department of Pathology, Yeshiva University Albert Einstein College of Medicine, Bronx, New York, USA
| | - Martha A Delaney
- Zoological Pathology Program, University of Illinois at Urbana-Champaign College of Veterinary Medicine, Urbana-Champaign, Illinois, USA
| | - Alessandra Piersigilli
- Laboratory of Comparative Pathology and the Genetically Modified Animal Phenotyping Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teresa L Southard
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Cory F Brayton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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6
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Okazaki Y. Asbestos‐induced mesothelial injury and carcinogenesis: Involvement of iron and reactive oxygen species. Pathol Int 2021; 72:83-95. [DOI: 10.1111/pin.13196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 12/11/2021] [Indexed: 11/27/2022]
Affiliation(s)
- Yasumasa Okazaki
- Department of Pathology and Biological Responses Nagoya University Graduate School of Medicine Showa‐Ku Nagoya Japan
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Tokarz DA, Gruebbel MM, Willson GA, Hardisty JF, Pearse G, Cesta MF. Spontaneous Primary Pleural Mesothelioma in Fischer 344 (F344) and Other Rat Strains: A Retrospective Review. Toxicol Pathol 2021; 50:167-175. [PMID: 34727809 DOI: 10.1177/01926233211053631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Spontaneous primary pleural mesotheliomas in Fischer 344 (F344) or other rat strains have rarely been reported. The objectives of this retrospective study were to develop historical incidence data and better characterize the light-microscopic morphology of these naturally occurring neoplasms in a large cohort of rats of several strains. A retrospective review was performed of National Toxicology Program (NTP) studies in rats conducted between 1980 and 2019 and comprising a total of 104,029 rats (51,326 males, 52,703 females), predominantly (90%) of the F344 strain. Of the 94,062 F344 rats surveyed, there were 30 cases of primary pleural mesotheliomas (22 males, 8 females). Of the 2998 Wistar Han rats surveyed, primary pleural mesotheliomas were present in 2 male rats. No primary pleural mesotheliomas were noted in male and female rats of other strains (6669 Sprague Dawley; 300 Osborne-Mendel). All primary pleural mesotheliomas in control and treated F344 and Wistar Han rats were considered spontaneous and unrelated to treatment. Based on light-microscopic evaluation of paraffin-embedded hematoxylin and eosin stained sections, only epithelioid and biphasic histologic subtypes were observed: 18 and 12 in F344 rats, respectively, and one each in Wistar Han rats. No sarcomatoid subtype cases were noted in any strain of rat.
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Affiliation(s)
- Debra A Tokarz
- Experimental Pathology Laboratories, Research Triangle Park, NC, USA
| | | | | | - Jerry F Hardisty
- Experimental Pathology Laboratories, Research Triangle Park, NC, USA
| | - Gail Pearse
- Non-Clinical Safety, In Vitro In Vivo Translation, GSK, Hertfordshire, United Kingdom
| | - Mark F Cesta
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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Finesso GE, McDevitt RA, Roy R, Brinster LR, Di Francesco A, Meade T, de Cabo R, Ferrucci L, Perdue KA. Impact of large granular lymphocyte leukemia on blood DNA methylation and epigenetic clock modeling in Fischer 344 rats. J Gerontol A Biol Sci Med Sci 2021; 77:956-963. [PMID: 34718551 DOI: 10.1093/gerona/glab328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Indexed: 11/14/2022] Open
Abstract
Age-dependent differences in methylation at specific cytosine-guanosine sites (CpGs) have been used in "epigenetic clock" formulas to predict age. Deviations of epigenetic age from chronological age are informative of health status and are associated with adverse health outcomes, including mortality. In most cases, epigenetic clocks are performed on methylation from DNA extracted from circulating blood cells. However, the effect of neoplastic cells in the circulation on estimation and interpretation of epigenetic clocks is not well understood. Here, we explored this using Fischer 344 (F344) rats, a strain that often develops large granular lymphocyte leukemia (LGL). We found clear histological markers of LGL pathology in the spleens and livers of 27 out of 61 rats aged 17-27 months. We assessed DNA methylation by reduced representation bisulfite sequencing with coverage of 3 million cytosine residues. Although LGL broadly increased DNA methylation variability, it did not change epigenetic aging. Despite this, inclusion of rats with LGL in clock training sets significantly altered predictor selection probability at 83 of 121 commonly utilized CpGs. Furthermore, models trained on rat samples that included individuals with LGL had greater absolute age error than those trained exclusively on LGL-free rats (39% increase; p<0.0001). We conclude that the epigenetic signals for aging and LGL are distinct, such that LGL assessment is not necessary for valid measures of epigenetic age in F344 rats. The precision and architecture of constructed epigenetic clock formulas, however, can be influenced by the presence of neoplastic hematopoietic cells in training set populations.
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Affiliation(s)
- Giovanni E Finesso
- Comparative Medicine Section, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Ross A McDevitt
- Comparative Medicine Section, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Roshni Roy
- Laboratory of Molecular Biology and Immunology, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Lauren R Brinster
- Office of Research Services, Division of Veterinary Resources, National Institutes of Health, Bethesda, MD
| | - Andrea Di Francesco
- Translational Gerontology Branch, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD.,Calico Life Sciences, South San Francisco, CA
| | - Theresa Meade
- Comparative Medicine Section, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
| | - Kathy A Perdue
- Comparative Medicine Section, National Institute on Aging - Intramural Research Program, National Institutes of Health, Baltimore, MD
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9
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Nishikawa A. Perspectives on the elimination of animal assays in the assessment of carcinogenicity. Regul Toxicol Pharmacol 2021; 126:105031. [PMID: 34437954 DOI: 10.1016/j.yrtph.2021.105031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/16/2021] [Accepted: 08/22/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Akiyoshi Nishikawa
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa, 210-9501, Japan; Division of Diagnostic Pathology, Saiseikai Utsunomiya Hospital, Takebayashi-machi 911-1, Utsunomiya, 321-0974, Japan.
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10
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Borghoff SJ, Fitch SE, Black MB, McMullen PD, Andersen ME, Chappell GA. A systematic approach to evaluate plausible modes of actions for mouse lung tumors in mice exposed to 4-methylimidozole. Regul Toxicol Pharmacol 2021; 124:104977. [PMID: 34174380 DOI: 10.1016/j.yrtph.2021.104977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/07/2021] [Accepted: 06/21/2021] [Indexed: 12/27/2022]
Abstract
The National Toxicology Program (NTP) reported that chronic dietary exposure to 4-methylimidazole (4-MeI) increased the incidence of lung adenomas/carcinomas beyond the normally high spontaneous rate in B6C3F1 mice. To examine plausible modes of action (MoAs) for mouse lung tumors (MLTs) upon exposure to high levels of 4-MeI, and their relevance in assessing human risk, a systematic approach was used to identify and evaluate mechanistic data (in vitro and in vivo) in the primary and secondary literature, along with high-throughput screening assay data. Study quality, relevance, and activity of mechanistic data identified across the evidence-base were organized according to key characteristics of carcinogens (KCCs) to identify potential key events in known or novel MLT MoAs. Integration of these evidence streams provided confirmation that 4-MeI lacks genotoxic and cytotoxic activity with some evidence to support a lack of mitogenic activity. Further evaluation of contextual and chemical-specific characteristics of 4-MeI was consequently undertaken. Due to lack of genotoxicity, along with transcriptomic and histopathological lung changes up to 28 and 90 days of exposure, the collective evidence suggests MLTs observed following exposure to high levels of 4-MeI develop at a late stage in the mouse chronic bioassay, albeit the exact MoA remains unclear.
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11
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Garnick L, Gillie C, Kozal J, Monnot A, Spencer P, Quinn J, Maier A. Hazard characterization of carcinogenicity, mutagenicity, and reproductive toxicity for short chain primary nitroalkanes. J Appl Toxicol 2021; 41:1910-1936. [PMID: 33847381 DOI: 10.1002/jat.4169] [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: 02/18/2021] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 11/11/2022]
Abstract
Nitroalkanes are organic aliphatic hydrocarbon compounds with a nitro moiety that are commonly used as solvents or intermediates to synthesize a variety of organic compounds due to their inherent reactivity. In June 2020, a harmonized classification and labeling (CLH) proposal was submitted to the European Chemicals Agency (ECHA) for the following harmonized carcinogenicity, mutagenicity, and reproductive toxicity ("CMR") classifications for nitromethane (NM), nitroethane (NE), and 1-nitropropane (1-NP): NM Carc. 1B and Repr. 1B; NE Repr. 1B; and 1-NP Repr. 2. In this assessment, a weight of evidence (WoE) evaluation of studies on animal carcinogenicity and reproductive and developmental toxicity, genotoxicity, and mode of action for these three nitroalkanes was performed to critically assess the relevance of the proposed CMR classifications. Overall, the WoE indicates that NM, NE, and 1-NP are not carcinogenic, genotoxic, nor selective reproductive or developmental toxicants. Based on our analysis, classifying NM, NE, and 1-NP as Category 2 reproductive toxicants is most appropriate. Furthermore, not classifying NE and 1-NP with respect to their carcinogenicity is appropriate based on the available studies for this endpoint coupled with negative results in genotoxicity studies, metabolism data, and in silico predictions. We determined that the classification for NM of Carc. 1B is not appropriate, based on the fact that rat mammary and harderian tumors are likely not relevant to humans and lung and liver tumors reported in mice were equivocal in their dose-response and statistical significance.
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Affiliation(s)
| | | | | | - Andy Monnot
- Cardno ChemRisk, Cardno, San Francisco, CA, USA
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12
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Wibbertmann A, Bitsch A, Kuper CF. Comprehensive analysis of chronic rodent inhalation toxicity studies for methyl acrylate with attention to test conditions exceeding a maximum tolerated concentration. Regul Toxicol Pharmacol 2021; 122:104900. [PMID: 33636299 DOI: 10.1016/j.yrtph.2021.104900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/11/2021] [Accepted: 02/16/2021] [Indexed: 10/22/2022]
Abstract
MA is a chemical intermediate, manufactured and processed within closed systems. While so far available subacute to chronic inhalation toxicity studies performed in compliance with OECD TG principles gave no indication of any carcinogenic potential for MA, a recent 2-year inhalation study with F344/DuCrlCrlj rats published in 2017 by the JBRC showed a statistically significant increase of squamous cell carcinoma in the nasal cavity of male rats at the highest tested concentration of 160 ppm. However, the results of the different studies in total indicate that this high concentration exceeded the MTC. As MA has a low potential for genotoxic and mutagenic activity, the increased tumour incidence can be attributed to a non-genotoxic mechanism, namely to a strong inflammatory response observed in this study. Together with mechanistic and epidemiologic data for other compounds related to nasal carcinogenesis via this mode of action, it can be concluded that the relevance of this increased tumour incidence in male rats for humans is questionable. Also, a long-term exposure to higher concentrations of MA is highly unlikely to be reached in the environment or at workplaces. Therefore, a risk for humans including cancer hazard is considered implausible.
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Affiliation(s)
- Axel Wibbertmann
- Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Nikolai-Fuchs-Str. 1, 30625, Hannover, Germany.
| | - Annette Bitsch
- Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Nikolai-Fuchs-Str. 1, 30625, Hannover, Germany
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Čoklo M, Maslov DR, Kraljević Pavelić S. Modulation of gut microbiota in healthy rats after exposure to nutritional supplements. Gut Microbes 2020; 12:1-28. [PMID: 32845788 PMCID: PMC7524141 DOI: 10.1080/19490976.2020.1779002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
INTRODUCTION Rats are experimental animals, frequently used as model organisms in the biomedical studies, and increasingly used to study the gut microbiota. Specifically, the aim of latter studies is either the elucidation of relationship between intestinal dysbiosis and diseases or the determination of nutrients or pharmaceutical agents which can cause the modulation in the presence or abundance of gut microbiota. AIM Herein, the research studies conducted on the gut microbiota of healthy rats are presented in a summarized and concise overview. The focus is on studies aimed to reveal the shifts in microbial composition and functional changes after exposure to various types of nutritional supplements. METHODS We performed the search of PubMed database using the term "rat gut microbiome microbiota" and examined studies aimed to assess the composition of gut microbiota in physiological homeostasis as well as the effect of various nutritional supplements on the gut microbiota of healthy rats.
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Affiliation(s)
- Mirna Čoklo
- Department of Biotechnology, Centre for High-throughput Technologies, University of Rijeka, Rijeka, Croatia
| | - Dina Rešetar Maslov
- Department of Biotechnology, Centre for High-throughput Technologies, University of Rijeka, Rijeka, Croatia
| | - Sandra Kraljević Pavelić
- Department of Biotechnology, Centre for High-throughput Technologies, University of Rijeka, Rijeka, Croatia,CONTACT Sandra Kraljević Pavelić University of Rijeka, trg braće Mažuranića 10, Rijeka 51000 and University of Rijeka Faculty of Health Studies, Viktora Cara Emina 5, 51000Rijeka, Croatia
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14
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Murray FJ, Monnot AD, Jacobson-Kram D, Cohen SM, Hardisty JF, Bandara SB, Kovochich M, Deore M, Pitchaiyan SK, Gelotte CK, Lai JCK, Atillasoy E, Hermanowski-Vosatka A, Kuffner E, Unice KM, Yang K, Gebremichael Y, Howell BA, Eichenbaum G. A critical review of the acetaminophen preclinical carcinogenicity and tumor promotion data and their implications for its carcinogenic hazard potential. Regul Toxicol Pharmacol 2020; 118:104801. [PMID: 33039518 DOI: 10.1016/j.yrtph.2020.104801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/11/2020] [Accepted: 10/06/2020] [Indexed: 12/22/2022]
Abstract
In 2019 the California Office of Environmental Health Hazard Assessment (OEHHA) initiated a review of the carcinogenic hazard potential of acetaminophen, including an assessment of the long-term rodent carcinogenicity and tumor initiation/promotion studies. The objective of the analysis herein was to inform this review process with a weight-of-evidence assessment of these studies and an assessment of the relevance of these models to humans. In most of the 14 studies, there were no increases in the incidences of tumors in any organ system. In the few studies in which an increase in tumor incidence was observed, there were factors such as absence of a dose response and a rodent-specific tumor supporting that these findings are not relevant to human hazard identification. In addition, we performed qualitative analysis and quantitative simulations of the exposures to acetaminophen and its metabolites and its toxicity profile; the data support that the rodent models are toxicologically relevant to humans. The preclinical carcinogenicity results are consistent with the broader weight of evidence assessment and evaluations of multiple international health authorities supporting that acetaminophen is not a carcinogenic hazard.
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Affiliation(s)
| | | | | | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | | | | | | | | | | | | | | | | | | | | | | | - Kyunghee Yang
- DILIsym Services Inc., Research Triangle Park, NC, USA
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15
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Revisiting the evidence for genotoxicity of acrylamide (AA), key to risk assessment of dietary AA exposure. Arch Toxicol 2020; 94:2939-2950. [PMID: 32494932 PMCID: PMC7415744 DOI: 10.1007/s00204-020-02794-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022]
Abstract
The weight of evidence pro/contra classifying the process-related food contaminant (PRC) acrylamide (AA) as a genotoxic carcinogen is reviewed. Current dietary AA exposure estimates reflect margins of exposure (MOEs) < 500. Several arguments support the view that AA may not act as a genotoxic carcinogen, especially not at consumer-relevant exposure levels: Biotransformation of AA into genotoxic glycidamide (GA) in primary rat hepatocytes is markedly slower than detoxifying coupling to glutathione (GS). Repeated feeding of rats with AA containing foods, bringing about uptake of 100 µg/kg/day of AA, resulted in dose x time-related buildup of AA-hemoglobin (Hb) adducts, whereas GA-Hb adducts remained within the background. Since hepatic oxidative biotransformation of AA into GA was proven by simultaneous urinary mercapturic acid monitoring it can be concluded that at this nutritional intake level any GA formed in the liver from AA is quantitatively coupled to GS to be excreted as mercapturic acid in urine. In an oral single dose–response study in rats, AA induced DNA N7-GA-Gua adducts dose-dependently in the high dose range (> 100 µg/kg b w). At variance, in the dose range below 100 µg/kg b.w. down to levels of average consumers exposure, DNA N7 -Gua lesions were found only sporadically, without dose dependence, and at levels close to the lower bound of similar human background DNA N7-Gua lesions. No DNA damage was detected by the comet assay within this low dose range. GA is a very weak mutagen, known to predominantly induce DNA N7-GA-Gua adducts, especially in the lower dose range. There is consensus that DNA N7-GA-Gua adducts exhibit rather low mutagenic potency. The low mutagenic potential of GA has further been evidenced by comparison to preactivated forms of other process-related contaminants, such as N-Nitroso compounds or polycyclic aromatic hydrocarbons, potent food borne mutagens/carcinogens. Toxicogenomic studies provide no evidence supporting a genotoxic mode of action (MOA), rather indicate effects on calcium signalling and cytoskeletal functions in rodent target organs. Rodent carcinogenicity studies show induction of strain- and species-specific neoplasms, with MOAs not considered likely predictive for human cancer risk. In summary, the overall evidence clearly argues for a nongenotoxic/nonmutagenic MOA underlying the neoplastic effects of AA in rodents. In consequence, a tolerable intake level (TDI) may be defined, guided by mechanistic elucidation of key adverse effects and supported by biomarker-based dosimetry in experimental systems and humans.
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16
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Gooderham NJ, Cohen SM, Eisenbrand G, Fukushima S, Guengerich FP, Hecht SS, Rietjens IMCM, Rosol TJ, Bastaki M, Linman MJ, Taylor SV. The safety evaluation of food flavoring substances: the role of genotoxicity studies. Crit Rev Toxicol 2020; 50:1-27. [PMID: 32162576 DOI: 10.1080/10408444.2020.1712589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Flavor and Extract Manufacturers Association (FEMA) Expert Panel relies on the weight of evidence from all available data in the safety evaluation of flavoring substances. This process includes data from genotoxicity studies designed to assess the potential of a chemical agent to react with DNA or otherwise cause changes to DNA, either in vitro or in vivo. The Panel has reviewed a large number of in vitro and in vivo genotoxicity studies during the course of its ongoing safety evaluations of flavorings. The adherence of genotoxicity studies to standardized protocols and guidelines, the biological relevance of the results from those studies, and the human relevance of these studies are all important considerations in assessing whether the results raise specific concerns for genotoxic potential. The Panel evaluates genotoxicity studies not only for evidence of genotoxicity hazard, but also for the probability of risk to the consumer in the context of exposure from their use as flavoring substances. The majority of flavoring substances have given no indication of genotoxic potential in studies evaluated by the FEMA Expert Panel. Examples illustrating the assessment of genotoxicity data for flavoring substances and the consideration of the factors noted above are provided. The weight of evidence approach adopted by the FEMA Expert Panel leads to a rational assessment of risk associated with consumer intake of flavoring substances under the conditions of use.
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Affiliation(s)
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Gerhard Eisenbrand
- Food Chemistry & Toxicology, University of Kaiserslautern (retired), Heidelberg, Germany
| | | | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | | | - Thomas J Rosol
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - Maria Bastaki
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Matthew J Linman
- Flavor and Extract Manufacturers Association, Washington, DC, USA
| | - Sean V Taylor
- Flavor and Extract Manufacturers Association, Washington, DC, USA
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17
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Wang TT, Yang J, Dighe S, Schmachtenberg MW, Leigh NT, Farber E, Onengut-Gumuscu S, Feith DJ, Ratan A, Loughran TP, Olson TL. Whole Genome Sequencing of Spontaneously Occurring Rat Natural Killer Large Granular Lymphocyte Leukemia Identifies JAK1 Somatic Activating Mutation. Cancers (Basel) 2020; 12:cancers12010126. [PMID: 31947841 PMCID: PMC7017127 DOI: 10.3390/cancers12010126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/20/2019] [Accepted: 12/25/2019] [Indexed: 02/08/2023] Open
Abstract
Large granular lymphocyte (LGL) leukemia arises spontaneously in elderly Fischer (F344) rats. This rodent model has been shown to emulate many aspects of the natural killer (NK) variant of human LGL leukemia. Previous transplantation of leukemic material into young F344 rats resulted in several strains of rat NK (RNK) primary leukemic cells. One strain, RNK-16, was adapted into the RNK-16 cell line and established as an aggressive NK-LGL leukemia model. Whole genome sequencing of the RNK-16 cell line identified 255,838 locations where the RNK16 had an alternate allele that was different from F334, including a mutation in Jak1. Functional studies showed Jak1 Y1034C to be a somatic activating mutation that mediated increased STAT signaling, as assessed by phosphoprotein levels. Sanger sequencing of Jak1 in RNK-1, -3, -7, and -16 found only RNK-16 to harbor the Y1034C Jak1 mutation. In vivo studies revealed that rats engrafted with RNK-16 primary material developed leukemia more rapidly than those engrafted with RNK-1, -3, and -7. Additionally, ex vivo RNK-16 spleen cells from leukemic rats exhibited increased STAT1, STAT3, and STAT5 phosphorylation compared to other RNK strains. Therefore, we report and characterize a novel gain-of-function Jak1 mutation in a spontaneous LGL leukemia model that results in increased downstream STAT signaling.
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Affiliation(s)
- T. Tiffany Wang
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Jun Yang
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Shubha Dighe
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Matthew W. Schmachtenberg
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Nathan T. Leigh
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Emily Farber
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA; (E.F.); (S.O.-G.); (A.R.)
| | - Suna Onengut-Gumuscu
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA; (E.F.); (S.O.-G.); (A.R.)
| | - David J. Feith
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Aakrosh Ratan
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA; (E.F.); (S.O.-G.); (A.R.)
| | - Thomas P. Loughran
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
| | - Thomas L. Olson
- Department of Medicine and University of Virginia Cancer Center, Division of Hematology & Oncology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (T.T.W.); (J.Y.); (S.D.); (M.W.S.); (N.T.L.); (D.J.F.)
- Correspondence: ; Tel.: +1-(434)-243-8332
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18
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Laube B, Michaelsen S, Meischner V, Hartwig A, Epe B, Schwarz M. Classification or non-classification of substances with positive tumor findings in animal studies: Guidance by the German MAK commission. Regul Toxicol Pharmacol 2019; 108:104444. [PMID: 31433998 DOI: 10.1016/j.yrtph.2019.104444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 08/10/2019] [Accepted: 08/14/2019] [Indexed: 12/19/2022]
Abstract
One of the important tasks of the German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (known as the MAK Commission) is in the evaluation of a potential for carcinogenicity of hazardous substances at the workplace. Often, this evaluation is critically based on data on carcinogenic responses seen in animal studies and, if positive tumor responses have been observed, this will mostly lead to a classification of the substance under investigation into one of the classes for carcinogens. However, there are cases where it can be demonstrated with a very high degree of confidence that the tumor findings in the experimental animals are not relevant for humans at the workplace and, therefore, the MAK Commission will not classify the respective substance into one of the classes for carcinogens. This paper will summarize the general criteria used by the MAK Commission for the categorization into "carcinogen" and "non-carcinogen" and compare this procedure with those used by other national and international organizations.
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Affiliation(s)
- Britta Laube
- Scientific Secretariat of the Senate Commission on the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission), Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Department of Food Chemistry and Toxicology, Karlsruhe, Germany
| | - Sandra Michaelsen
- Scientific Secretariat of the Senate Commission on the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission), Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Department of Food Chemistry and Toxicology, Karlsruhe, Germany
| | - Veronika Meischner
- Scientific Secretariat of the Senate Commission on the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission), Institute for Applied Biosciences, Karlsruhe Institute of Technology (KIT), Department of Food Chemistry and Toxicology, Karlsruhe, Germany
| | - Andrea Hartwig
- Food Chemistry and Toxicology, Institute of Applied Bioscience, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, 76131, Karlsruhe, Germany
| | - Bernd Epe
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55099, Mainz, Germany
| | - Michael Schwarz
- Dept. of Experimental and Clinical Pharmacology and Toxicology, Dept. Toxicology, Eberhard Karls University, Wilhelmstr. 56, 72074, Tübingen, Germany.
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Herman D, Mantle P. Immunohistochemical Review of Leydig Cell Lesions in Ochratoxin A-Treated Fischer Rats and Controls. Toxins (Basel) 2019; 11:E480. [PMID: 31434192 PMCID: PMC6723183 DOI: 10.3390/toxins11080480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/22/2019] [Accepted: 08/12/2019] [Indexed: 01/07/2023] Open
Abstract
Ochratoxin A is best known as a potent renal carcinogen in male rats and mice after necessarily protracted ingestion, although valid extrapolation to any human disease has not been verified. The hypothesis that the toxin is a cause of human testicular cancer was proposed a decade ago and has proliferated since, partly through incomplete study of the scientific literature. Archived tumorous rat testes were available from Fischer F344 rats exposed to continuous dietary exposure for half of or the whole life in London in the 2000s. Renal cancer occurred in some of these cases and testicular tumours were observed frequently, as expected, in both treated and untreated animals. Application of clinical immunohistochemistry has for the first time consistently diagnosed the testicular hypertrophy in toxin-treated rats as Leydig cell tumours. Comparison is made with similar analysis of tumorous testes from control (untreated) rats from U.S. National Toxicology Program studies, both of ochratoxin A (1989) and the more recent one on Ginkgo biloba. All have been found to have identical pathology as being of sex cord-stromal origin. Such are rare in humans, most being of germinal cell origin. The absence of experimental evidence of any specific rat testicular cellular pathology attributable to long-term dietary ochratoxin A exposure discredits any experimental animal evidence of testicular tumorigenicity. Thus, no epidemiological connection between ochratoxin A and the incidence of human testicular cancer can be justified scientifically.
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Affiliation(s)
- Diana Herman
- Pathology Department, County Hospital Timisoara, Timisoara 300736, Romania
| | - Peter Mantle
- Centre for Environmental Policy, Imperial College London, South Kensington, London SW7 2AZ, UK.
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20
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Aasa J, Granath F, Törnqvist M. Cancer risk estimation of glycidol based on rodent carcinogenicity studies, a multiplicative risk model and in vivo dosimetry. Food Chem Toxicol 2019; 128:54-60. [PMID: 30914355 DOI: 10.1016/j.fct.2019.03.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 03/18/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022]
Abstract
Here we evaluate a multiplicative (relative) risk model for improved cancer risk estimation of genotoxic compounds. According to this model, cancer risk is proportional to the background tumor incidence and to the internal dose of the genotoxic compound. Furthermore, the relative risk coefficient per internal dose is considered to be approximately the same across tumor sites, sex, and species. In the present study, we demonstrate that the relative risk model is valid for cancer risk estimation of glycidol, a common food contaminant. Published tumor data from glycidol carcinogenicity studies in mice and rats were evaluated in combination with internal dose estimates from hemoglobin adduct measurements in blood from mice and rats treated with glycidol in short-term studies. A good agreement between predicted and observed tumor incidence in responding sites was demonstrated in the animals, supporting a relative risk coefficient that is independent of tumor site, sex, and species. There was no significant difference between the risk coefficients for mice (5.1% per mMh) and rats (5.4% per mMh) when considering internal doses of glycidol. Altogether, this mechanism-based risk model gives a reliable risk coefficient, which then was extrapolated to humans considering internal dose, and background cancer incidence.
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Affiliation(s)
- Jenny Aasa
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Sweden.
| | - Fredrik Granath
- Department of Medicine, Solna, Clinical Epidemiology Division, Karolinska Institute, Stockholm, Sweden
| | - Margareta Törnqvist
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Sweden.
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21
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Maru Y, Onuma K, Ochiai M, Imai T, Hippo Y. Shortcuts to intestinal carcinogenesis by genetic engineering in organoids. Cancer Sci 2019; 110:858-866. [PMID: 30637899 PMCID: PMC6398887 DOI: 10.1111/cas.13938] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/27/2018] [Accepted: 01/07/2019] [Indexed: 01/03/2023] Open
Abstract
Inactivation of the Adenomatous polyposis coli (APC) gene is an initiating and the most relevant event in most sporadic cases of colorectal cancer, providing a rationale for using Apc‐mutant mice as the disease model. Whereas carcinogenesis has been observed only at the organism level, the recent development of the organoid culture technique has enabled long‐term propagation of intestinal stem cells in a physiological setting, raising the possibility that organoids could serve as an alternative platform for modeling colon carcinogenesis. Indeed, it is demonstrated in the present study that lentivirus‐based RNAi‐mediated knockdown of Apc in intestinal organoids gave rise to subcutaneous tumors upon inoculation in immunodeficient mice. Reconstitution of common genetic aberrations in organoids resulted in development of various lesions, ranging from aberrant crypt foci to full‐blown cancer, recapitulating multi‐step colorectal tumorigenesis. Due to its simplicity and utility, similar organoid‐based approaches have been applied to both murine and human cells in many investigations, to gain mechanistic insight into tumorigenesis, to validate putative tumor suppressor genes or oncogenes, and to establish preclinical models for drug discovery. In this review article, we provide a multifaceted overview of these types of approaches that will likely accelerate and advance research on colon cancer.
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Affiliation(s)
- Yoshiaki Maru
- Department of Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Chiba, Japan
| | - Kunishige Onuma
- Division of Pathological Biochemistry, School of Life Science, Tottori University, Yonago, Japan
| | - Masako Ochiai
- Central Animal Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Toshio Imai
- Central Animal Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Yoshitaka Hippo
- Department of Molecular Carcinogenesis, Chiba Cancer Center Research Institute, Chiba, Japan.,Central Animal Division, National Cancer Center Research Institute, Tokyo, Japan
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22
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Jean D, Jaurand MC. Mesotheliomas in Genetically Engineered Mice Unravel Mechanism of Mesothelial Carcinogenesis. Int J Mol Sci 2018; 19:E2191. [PMID: 30060470 PMCID: PMC6121615 DOI: 10.3390/ijms19082191] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 07/23/2018] [Indexed: 12/14/2022] Open
Abstract
Malignant mesothelioma (MM), a rare and severe cancer, mainly caused as a result of past-asbestos exposure, is presently a public health concern. Current molecular studies aim to improve the outcome of the disease, providing efficient therapies based on the principles of precision medicine. To model the molecular profile of human malignant mesothelioma, animal models have been developed in rodents, wild type animals and genetically engineered mice harbouring mutations in tumour suppressor genes, especially selecting genes known to be inactivated in human malignant mesothelioma. Animals were either exposed or not exposed to asbestos or to other carcinogenic fibres, to understand the mechanism of action of fibres at the molecular level, and the role of the selected genes in mesothelial carcinogenesis. The aim of the manuscript was to compare mesothelioma models to human malignant mesothelioma and to specify the clue genes playing a role in mesothelial carcinogenesis. Collectively, MM models recapitulate the clinical features of human MM. At least two altered genes are needed to induce malignant mesothelioma in mice. Two pathways regulated by Cdkn2a and Trp53 seem independent key players in mesothelial carcinogenesis. Other genes and pathways appear as bona fide modulators of the neoplastic transformation.
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Affiliation(s)
- Didier Jean
- Inserm, UMR-1162, Génomique Fonctionnelle des Tumeurs Solides, F-75010 Paris, France.
- Université Paris Descartes, Labex Immuno-Oncologie, Sorbonne Paris Cité, F-75000 Paris, France.
- Institut Universitaire d'Hématologie, Université Paris Diderot, Sorbonne Paris Cité, F-75010 Paris, France.
- Université Paris 13, Sorbonne Paris Cité, F-93206 Saint-Denis, France.
| | - Marie-Claude Jaurand
- Inserm, UMR-1162, Génomique Fonctionnelle des Tumeurs Solides, F-75010 Paris, France.
- Université Paris Descartes, Labex Immuno-Oncologie, Sorbonne Paris Cité, F-75000 Paris, France.
- Institut Universitaire d'Hématologie, Université Paris Diderot, Sorbonne Paris Cité, F-75010 Paris, France.
- Université Paris 13, Sorbonne Paris Cité, F-93206 Saint-Denis, France.
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23
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Khokhlov AN, Klebanov AA, Morgunova GV. On Choosing Control Objects in Experimental Gerontological Research. ACTA ACUST UNITED AC 2018. [DOI: 10.3103/s0096392518020049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Chiu WA, Rusyn I. Advancing chemical risk assessment decision-making with population variability data: challenges and opportunities. Mamm Genome 2018; 29:182-189. [PMID: 29299621 PMCID: PMC5849521 DOI: 10.1007/s00335-017-9731-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/27/2017] [Indexed: 02/06/2023]
Abstract
Characterizing population variability, including identifying susceptible populations and quantifying their increased susceptibility, is an important aspect of chemical risk assessment, but one that is challenging with traditional experimental models and risk assessment methods. New models and methods to address population variability can be used to advance the human health assessments of chemicals in three key areas. First, with respect to hazard identification, evaluating toxicity using population-based in vitro and in vivo models can potentially reduce both false positive and false negative signals. Second, with respect to evaluating mechanisms of toxicity, enhanced ability to do genetic mapping using these models allows for the identification of key biological pathways and mechanisms that may be involved in toxicity and/or susceptibility. Third, with respect to dose-response assessment, population-based toxicity data can serve as a surrogate for human variability, and thus be used to quantitatively estimate the degree of human toxicokinetic/toxicodynamic variability and thereby increase confidence in setting health-protective exposure limits. A number of case studies have been published that demonstrate the potential opportunities for improving risk assessment and decision-making, and include studies using Collaborative Cross and Diversity Outbred mice, as well as populations of human cell lines from the 1000 Genomes project. Key challenges include the need to apply more sophisticated computational and statistical models analyzing population-based toxicity data, and the need to integrate these more complex analyses into risk assessments and decision-making.
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Affiliation(s)
- Weihsueh A Chiu
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA.
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843, USA
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25
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Silano V, Bolognesi C, Castle L, Chipman K, Cravedi JP, Engel KH, Fowler P, Franz R, Grob K, Gürtler R, Husøy T, Kärenlampi S, Milana MR, Pfaff K, Riviere G, Srinivasan J, Tavares Poças MDF, Tlustos C, Wölfle D, Zorn H, Benigni R, Binderup ML, Brimer L, Marcon F, Marzin D, Mosesso P, Mulder G, Oskarsson A, Svendsen C, Anastassiadou M, Carfì M, Saarma S, Mennes W. Safety of benzophenone to be used as flavouring. EFSA J 2017; 15:e05013. [PMID: 32625332 PMCID: PMC7010149 DOI: 10.2903/j.efsa.2017.5013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Benzophenone [FL-no: 07.032] has been evaluated as a flavouring substance, in FGE.69, by the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food in 2008. Benzophenone was evaluated also by JECFA (2011) and by IARC (2013) based on studies that were not considered in the EFSA opinion on FGE.69. Therefore, the Commission requested the CEF Panel to carry out a review of existing literature on the safety of this flavouring substance. In the framework of the evaluation of benzophenone as a food contact material, the CEF Panel established a tolerable daily intake (TDI) of 0.03 mg/kg body weight (bw) per day (2009). In the present Opinion, the Panel considered the already existing evaluations by EFSA, JECFA, IARC and available literature data on benzophenone toxicity. Moreover, new data on the use levels of benzophenone as a flavouring substance have been provided. The Panel considers that there is no concern with respect to genotoxicity. The Panel considers the endocrine activities of benzophenone and its metabolite 4-hydroxybenzophenone as weak and not directly related to the observed toxic effects including the neoplastic effects in rodents. The Panel confirms that the conservative approach taken by EFSA (2009) to derive a TDI of 0.03 mg/kg bw for benzophenone is appropriate to cover the non-neoplastic effects in the chronic toxicity studies and the neoplastic effects induced in the rodent carcinogenicity studies. The TDI is in the same order of magnitude as the chronic dietary exposure of adults and children to benzophenone (10-20 μg/kg bw per day) for the amount of added flavouring substance. The Panel considers that the calculated TDI and exposure estimate are based on conservative assumptions. The Panel concludes that there is no safety concern for benzophenone under the current condition of use as a flavouring substance.
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26
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Elmore SA, Aeffner F, Bangari DS, Crabbs TA, Fossey S, Gad SC, Haschek WM, Hoane JS, Janardhan K, Kovi RC, Pearse G, Wancket LM, Quist EM. Proceedings of the 2017 National Toxicology Program Satellite Symposium. Toxicol Pathol 2017; 45:799-833. [PMID: 29113559 PMCID: PMC5743204 DOI: 10.1177/0192623317733924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The 2017 annual National Toxicology Program Satellite Symposium, entitled "Pathology Potpourri," was held in Montreal, Quebec, Canada at the Society of Toxicologic Pathology's 36th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers' talks along with select images that were used by the audience for voting and discussion. Various lesions and other topics covered during the symposium included renal papillary degeneration in perinatally exposed animals, an atriocaval mesothelioma, an unusual presentation of an alveolar-bronchiolar carcinoma, a paraganglioma of the organ of Zuckerkandl (also called an extra-adrenal pheochromocytoma), the use of human muscle samples to illustrate the challenges of manual scoring of fluorescent staining, intertubular spermatocytic seminomas, medical device pathology assessment and discussion of the approval process, collagen-induced arthritis, incisor denticles, ameloblast degeneration and poorly mineralized enamel matrix, connective tissue paragangliomas, microcystin-LR toxicity, perivascular mast cells in the forebrain thalamus unrelated to treatment, and 2 cases that provided a review of the International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) bone nomenclature and recommended application of the terminology in routine nonclinical toxicity studies.
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Affiliation(s)
- Susan A. Elmore
- National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina
| | | | | | - Torrie A. Crabbs
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina
| | | | | | - Wanda M. Haschek
- University of Illinois, Department of Pathobiology, Urbana, Illinois
| | | | | | - Ramesh C. Kovi
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina
| | - Gail Pearse
- GlaxoSmithKline, Ware, Hertfordshire, United Kingdom
| | | | - Erin M. Quist
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina
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27
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Dye JA, Gibbs-Flournoy EA, Richards JH, Norwood J, Kraft K, Hatch GE. Neonatal rat age, sex and strain modify acute antioxidant response to ozone. Inhal Toxicol 2017; 29:291-303. [PMID: 28880688 DOI: 10.1080/08958378.2017.1369602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the US and its impact continues to increase in women. Oxidant insults during critical periods of early life appear to increase risk of COPD through-out the life course. To better understand susceptibility to early life exposure to oxidant air pollutants we used Fisher (F344), Sprague-Dawley (SD) and Wistar (WIS) male and female neonatal rat pups to assess: (A) if strain (i.e. genetics), sex, or stage of early life development affected baseline lung antioxidant or redox enzyme levels and (B) if these same factors modulated antioxidant responsiveness to acute ozone exposure (1 ppm × 2 h) on post-natal day (PND) 14, 21, or 28. In air-exposed pups from PND14-28, some parameters were unchanged (e.g. uric acid), some decreased (e.g. superoxide dismutase), while others increased (e.g. glutathione recycling enzymes) especially post-weaning. Lung total glutathione levels decreased in F344 and SD pups, but were relatively unchanged in WIS pups. Post-ozone exposure, data suggest that: (1) the youngest (PND14) pups were the most adversely affected; (2) neonatal SD and WIS pups, especially females, were more prone to ozone effects than males of the same age and (3) F344 neonates (females and males) were less susceptible to oxidative lung insult, not unlike F344 adults. Differences in antioxidant levels and responsiveness between sexes and strains and at different periods of development may provide a basis for assessing later life health outcomes - with implications for humans with analogous genetic or dietary-based lung antioxidant deficits.
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Affiliation(s)
- Janice A Dye
- a National Health and Environmental Research Laboratory (NHEERL) Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park, Durham , NC , USA
| | - Eugene A Gibbs-Flournoy
- b ORISE, Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park , NC , USA
| | - Judy H Richards
- a National Health and Environmental Research Laboratory (NHEERL) Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park, Durham , NC , USA
| | - Joel Norwood
- a National Health and Environmental Research Laboratory (NHEERL) Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park, Durham , NC , USA
| | | | - Gary E Hatch
- a National Health and Environmental Research Laboratory (NHEERL) Office of Research and Development , U.S. Environmental Protection Agency , Research Triangle Park, Durham , NC , USA
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28
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Cartus A, Schrenk D. Current methods in risk assessment of genotoxic chemicals. Food Chem Toxicol 2017; 106:574-582. [DOI: 10.1016/j.fct.2016.09.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/06/2016] [Accepted: 09/08/2016] [Indexed: 12/15/2022]
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29
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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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