1
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Wang E, Shuryak I, Brenner DJ. A competing risks machine learning study of neutron dose, fractionation, age, and sex effects on mortality in 21,000 mice. Sci Rep 2024; 14:17974. [PMID: 39095647 PMCID: PMC11297256 DOI: 10.1038/s41598-024-68717-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 07/25/2024] [Indexed: 08/04/2024] Open
Abstract
This study explores the impact of densely-ionizing radiation on non-cancer and cancer diseases, focusing on dose, fractionation, age, and sex effects. Using historical mortality data from approximately 21,000 mice exposed to fission neutrons, we employed random survival forest (RSF), a powerful machine learning algorithm accommodating nonlinear dependencies and interactions, treating cancer and non-cancer outcomes as competing risks. Unlike traditional parametric models, RSF avoids strict assumptions and captures complex data relationships through decision tree ensembles. SHAP (SHapley Additive exPlanations) values and variable importance scores were employed for interpretation. The findings revealed clear dose-response trends, with cancer being the predominant cause of mortality. SHAP value dose-response shapes differed, showing saturation for cancer hazard at high doses (> 2 Gy) and a more linear pattern at lower doses. Non-cancer responses remained more linear throughout the entire dose range. There was a potential inverse dose rate effect for cancer, while the evidence for non-cancer was less conclusive. Sex and age effects were less pronounced. This investigation, utilizing machine learning, enhances our understanding of the patterns of non-cancer and cancer mortality induced by densely-ionizing radiations, emphasizing the importance of such approaches in radiation research, including space travel and radioprotection.
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Affiliation(s)
- Eric Wang
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA.
| | - Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th street, VC-11, New York, NY, 10032, USA
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2
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Zhang X, Felter SP, Api AM, Joshi K, Selechnik D. A Cautionary tale for using read-across for cancer hazard classification: Case study of isoeugenol and methyl eugenol. Regul Toxicol Pharmacol 2022; 136:105280. [DOI: 10.1016/j.yrtph.2022.105280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/16/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
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3
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Lynch HN, Kozal JS, Russell AJ, Thompson WJ, Divis HR, Freid RD, Calabrese EJ, Mundt KA. Systematic review of the scientific evidence on ethylene oxide as a human carcinogen. Chem Biol Interact 2022; 364:110031. [PMID: 35779612 DOI: 10.1016/j.cbi.2022.110031] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/16/2022] [Accepted: 06/24/2022] [Indexed: 11/25/2022]
Abstract
Ethylene oxide is a highly reactive chemical primarily used as an intermediate in chemical production and as a sterilant of medical equipment and food products; it also is produced endogenously as a result of physiological processes. We conducted a systematic review of the potential carcinogenicity of inhaled ethylene oxide in humans using methods that adhere to PRIMSA guidelines and that incorporate aspects from the Institute of Medicine (IOM) (now the National Academy of Medicine) as well as several US Environmental Protection Agency (EPA) frameworks for systematic reviews. After a comprehensive literature search and selection process, study quality was evaluated following a method adapted from the EPA Toxic Substances Control Act (TSCA) framework. The literature screening and selection process identified 24 primary studies in animals or humans and more than 50 mechanistic studies. Integrating epidemiological, animal, and mechanistic literature on ethylene oxide and cancer according to the IOM framework yielded classifications of suggestive evidence of no association between ethylene oxide and stomach cancer, breast cancer and lymphohematopoietic malignancies at human relevant exposures. However, we acknowledge that there is additional uncertainty in the classification for lymphohematopoietic malignancies owing to a paucity of evidence for specific types of these tumors, each of which is a distinct disease entity of possibly unique etiology.
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Affiliation(s)
| | | | | | | | | | | | | | - Kenneth A Mundt
- Cardno ChemRisk, Boston, MA, USA; University of Massachusetts, Amherst, MA, USA
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4
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Campion SN, Nowland WS, Gropp K, Liu C, Ritenour HN, Syed J, Catlin N, Stethem CM, Coskran TM, Cappon GD. Assessment of postnatal femur development in Wistar Han rats. Birth Defects Res 2022. [DOI: 10.1002/bdr2.2071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sarah N. Campion
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
| | | | - Kathryn Gropp
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
| | - Chang‐Ning Liu
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
| | | | - Jameel Syed
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
| | - Natasha Catlin
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
| | | | | | - Gregg D. Cappon
- Pfizer Worldwide Research, Development & Medical Groton Connecticut USA
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5
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Masumura K, Ando T, Ukai A, Fujiwara S, Yokose S, You X, Suzuki T, Hayashi H, Nohmi T, Takagi H, Honma M. New homozygous gpt delta transgenic rat strain improves an efficiency of the in vivo mutagenicity assay. Genes Environ 2021; 43:25. [PMID: 34158118 PMCID: PMC8220708 DOI: 10.1186/s41021-021-00195-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/27/2021] [Indexed: 02/22/2023] Open
Abstract
Background Gene mutation assays in transgenic rodents are useful tools to investigate in vivo mutagenicity in a target tissue. Using a lambda EG10 transgene containing reporter genes, gpt delta transgenic mice and rats have been developed to detect point mutations and deletions. The transgene is integrated in the genome and can be rescued through an in vitro packaging reaction. However, the packaging efficiency is lower in gpt delta rats than in mice, because of the transgene in gpt delta rats being heterozygous and in low copy number. To improve the packaging efficiency, we herein describe a newly developed homozygous gpt delta rat strain. Results The new gpt delta rat has a Wistar Hannover background and has been successfully maintained as homozygous for the transgene. The packaging efficiency in the liver was 4 to 8 times higher than that of existing heterozygous F344 gpt delta rats. The frequency of gpt point mutations significantly increased in the liver and bone marrow of N-nitroso-N-ethylurea (ENU)- and benzo[a]pyrene (BaP)-treated rats. Spi− deletion frequencies significantly increased in the liver and bone marrow of BaP-treated rats but not in ENU-treated rats. Whole genome sequencing analysis identified ≥ 30 copies of lambda EG10 transgenes integrated in rat chromosome 1. Conclusions The new homozygous gpt delta rat strain showed a higher packaging efficiency, and could be useful for in vivo gene mutation assays in rats. Supplementary Information The online version contains supplementary material available at 10.1186/s41021-021-00195-1.
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Affiliation(s)
- Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Tomoko Ando
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Akiko Ukai
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Sho Fujiwara
- Biotechnical Center, Japan SLC, Inc., 3-5-1, Aoihigashi, Naka-ku, Hamamatsu-shi, Shizuoka, 433-8114, Japan
| | - Shigeo Yokose
- Biotechnical Center, Japan SLC, Inc., 3-5-1, Aoihigashi, Naka-ku, Hamamatsu-shi, Shizuoka, 433-8114, Japan
| | - Xinyue You
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, 210-9501, Kawasaki-shi, Kanagawa, Japan.,School of Public Health, Hongqiao International Institute of Medicine, Shanghai Jiao Tong University School of Medicine, 227 South Chongqing Road, Shanghai, 200025, China
| | - Takayoshi Suzuki
- School of Public Health, Hongqiao International Institute of Medicine, Shanghai Jiao Tong University School of Medicine, 227 South Chongqing Road, Shanghai, 200025, China
| | - Hiroyuki Hayashi
- Biologics Business Planning & Operation Dept, Meiji Seika Pharma Co., Ltd, 2-4-16 Kyobashi Chuo- ku, Tokyo, 104-8002, Japan
| | - Takehiko Nohmi
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Hisayoshi Takagi
- Biotechnical Center, Japan SLC, Inc., 3-5-1, Aoihigashi, Naka-ku, Hamamatsu-shi, Shizuoka, 433-8114, Japan
| | - Masamitsu Honma
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
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6
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Ladd TB, Johnson JA, Mumaw CL, Greve HJ, Xuei X, Simpson E, Barnes MA, Green BJ, Croston TL, Ahmed C, Lemons A, Beezhold DH, Block ML. Aspergillus versicolor Inhalation Triggers Neuroimmune, Glial, and Neuropeptide Transcriptional Changes. ASN Neuro 2021; 13:17590914211019886. [PMID: 34098774 PMCID: PMC8191080 DOI: 10.1177/17590914211019886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence associates indoor fungal exposure with deleterious central nervous system (CNS) health, such as cognitive and emotional deficits in children and adults, but the specific mechanisms by which it might impact the brain are poorly understood. Mice were exposed to filtered air, heat-inactivated Aspergillus versicolor (3 × 105 spores), or viable A. versicolor (3 × 105 spores) via nose-only inhalation exposure 2 times per week for 1, 2, or 4 weeks. Analysis of cortex, midbrain, olfactory bulb, and cerebellum tissue from mice exposed to viable A. versicolor spores for 1, 2, and 4 weeks revealed significantly elevated pro-inflammatory (Tnf and Il1b) and glial activity (Gdnf and Cxc3r1) gene expression in several brain regions when compared to filtered air control, with the most consistent and pronounced neuroimmune response 48H following the 4-week exposure in the midbrain and frontal lobe. Bulk RNA-seq analysis of the midbrain tissue confirmed that 4 weeks of A. versicolor exposure resulted in significant transcriptional enrichment of several biological pathways compared to the filtered air control, including neuroinflammation, glial cell activation, and regulation of postsynaptic organization. Upregulation of Drd1, Penk, and Pdyn mRNA expression was confirmed in the 4-week A. versicolor exposed midbrain tissue, highlighting that gene expression important for neurotransmission was affected by repeated A. versicolor inhalation exposure. Taken together, these findings indicate that the brain can detect and respond to A. versicolor inhalation exposure with changes in neuroimmune and neurotransmission gene expression, providing much needed insight into how inhaled fungal exposures can affect CNS responses and regulate neuroimmune homeostasis.
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Affiliation(s)
- Thatcher B Ladd
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - James A Johnson
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Christen L Mumaw
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Hendrik J Greve
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Xiaoling Xuei
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ed Simpson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Mark A Barnes
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States
| | - Brett J Green
- Office of the Director, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States
| | - Tara L Croston
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States
| | - Chandrama Ahmed
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Angela Lemons
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States
| | - Donald H Beezhold
- Office of the Director, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, United States
| | - Michelle L Block
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, United States.,Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana, United States
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7
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Monnot AD, Kovochich M, Bandara SB, Wilsey JT, Christian WV, Eichenbaum G, Perkins LEL, Hasgall P, Taneja M, Connor K, Sague J, Nasseri-Aghbosh B, Marcello S, Vreeke M, Katz LB, Reverdy EE, Thelen H, Unice K. A hazard evaluation of the reproductive/developmental toxicity of cobalt in medical devices. Regul Toxicol Pharmacol 2021; 123:104932. [PMID: 33872739 DOI: 10.1016/j.yrtph.2021.104932] [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: 10/08/2020] [Revised: 04/08/2021] [Accepted: 04/13/2021] [Indexed: 12/13/2022]
Abstract
Cobalt (Co) is an essential element with human exposure occurring from the diet, supplement ingestion, occupational sources, and medical devices. The European Chemical Agency (ECHA) recently voted to classify Co metal as a Reproductive Hazard Category 1B; presumed human reproductive toxicant due to adverse testicular effects in male rodents. A weight of evidence evaluation of the preclinical reproductive and developmental toxicity studies and available clinical data was performed to critically evaluate the relevance of this proposed classification for Co in medical devices. Reproductive responses to Co are limited to the male testes and sperm function following high systemic exposure in rodents, only at Co concentrations/doses that result in overt toxicity (i.e., above the maximum tolerable dose (MTD)). The potential mechanisms of Co reproductive/developmental toxicity, including its indirect mode of action in the testes and relevance to humans, are discussed. The available preclinical and clincial evidence suggests that it would be more appropriate to classify Co as a Reproductive Hazard Category 2 compound: suspected human reproductive toxicant and, in the case of Co-containing medical devices, it should not be considered a reproductive hazard.
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Affiliation(s)
- Andrew D Monnot
- Cardno ChemRisk, 235 Pine Street, Suite 2300, San Francisco, CA, 94104, USA.
| | - Michael Kovochich
- Cardno ChemRisk, 30 North LaSalle Street, Suite 3910, Chicago, IL, 60602, USA
| | - Suren B Bandara
- Cardno ChemRisk, 235 Pine Street, Suite 2300, San Francisco, CA, 94104, USA
| | - Jared T Wilsey
- Smith & Nephew, 1450 E Brooks Rd, Memphis, TN, 3811, USA
| | | | - Gary Eichenbaum
- Johnson and Johnson, 410 George St, New Brunswick, NJ, 08901, USA
| | | | | | | | - Kevin Connor
- Boston Scientific, 100 Boston Scientific Way, Marlborough, MA, 01752, USA
| | - Jorge Sague
- Stryker, 2825 Airview Boulevard, Kalamazoo, MI, 49002, USA
| | | | - Stephen Marcello
- Johnson and Johnson, 410 George St, New Brunswick, NJ, 08901, USA
| | - Mark Vreeke
- Edwards, One Edwards Way, Irvine, CA, 92614, USA
| | - Laurence B Katz
- LifeScan Global Corporation, 20 Valley Stream Parkway, Malvern, PA, 19355, USA
| | | | | | - Kenneth Unice
- Cardno ChemRisk, 20 Stanwix Street, Suite 505, Pittsburgh, PA, 15222, USA
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8
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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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9
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Felter SP, Llewelyn C, Navarro L, Zhang X. How the 62-year old Delaney Clause continues to thwart science: Case study of the flavor substance β-myrcene. Regul Toxicol Pharmacol 2020; 115:104708. [PMID: 32522581 DOI: 10.1016/j.yrtph.2020.104708] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 10/24/2022]
Abstract
The Delaney Clause is a provision of the 1958 Food Additive Amendment to the Food, Drug and Cosmetic Act of 1938 which stipulates that if a substance is found by the Food and Drug Administration to be carcinogenic in any species of animal or in humans, then it cannot be used as a food additive. This paper presents a case study of β-myrcene, one of seven synthetic substances that was challenged under the Delaney Clause, ultimately resulting in revocation of its regulatory approval as a food additive despite a lack of safety concern. While it is listed as a synthetic flavor in 21 CFR 172.515, β-myrcene is also a substance naturally occurring in a number of dietary plants. The exposure level to naturally-occurring β-myrcene is orders of magnitude higher (estimated to be 16,500 times greater) than the exposure via β-myrcene added to food as a flavoring substance. The National Toxicology Program conducted genotoxicity testing (negative), a 13-week range-finding study, and a two-year cancer bioassay in B6C3F1 mice and F344/N rats. An increase in liver tumors was seen in male mice and kidney tumors in male rats, ultimately resulting in β-myrcene being classified by IARC as a Class 2B carcinogen and being listed on California Proposition 65; in contrast, β-myrcene is not classified as a carcinogen by any other regulatory authority. The doses administered in the NTP bioassay were five-six orders of magnitude higher than human exposures, and the FDA concluded after a thorough evaluation that there was no safety concern associated with the use of β-myrcene as a flavor substance at the current use level. The Delaney Clause, however, does not consider the exposure potential or the human health relevance of effects observed in animals. The lack of options available to the US FDA led to the 2018 decision to remove β-myrcene from the list of approved food additives. This revocation has contributed to the ongoing erosion of trust in regulatory agencies (and industry), which has both economic implications for food manufacturers and consumers alike, and implications for consumer perception of safety of the US food supply. It is time for us to reconsider the rationale behind any legislation that relies on classification alone, and whether there is, in fact, a reason to still classify nongenotoxic carcinogens at all.
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Affiliation(s)
- Susan P Felter
- Procter & Gamble, Central Product Safety, Mason, OH, USA.
| | - Craig Llewelyn
- Toxicology Regulatory Services, Charlottesville, VA, USA
| | | | - Xiaoling Zhang
- Procter & Gamble, Central Product Safety, Mason, OH, USA
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10
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MacGregor JA, White DJ, Williams AL. The limitations of using the NTP chronic bioassay on vanadium pentoxide in risk assessments. Regul Toxicol Pharmacol 2020; 113:104650. [PMID: 32246946 DOI: 10.1016/j.yrtph.2020.104650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 02/20/2020] [Accepted: 03/24/2020] [Indexed: 10/24/2022]
Abstract
Regulatory interest in assessing the health effects of vanadium compounds is hindered by the limited chronic toxicity data available. The National Toxicology Program (NTP) conducted a robust chronic inhalation bioassay of crystalline vanadium pentoxide (V2O5), but this study has noteworthy limitations. Multiple dose range-finding studies were conducted at two separate laboratories that showed cross-laboratory differences in lung pathology (inflammation) in both species and likely complicated dose-selection. In mice, the only tissue pathology (inflammation and tumors) was at the site of entry, the respiratory system. Although significantly different from control, because lung tumor incidences were at a maximal level across all concentrations tested, the ability to extrapolate risks to the public is problematic. In rats, lung inflammation and vanadium lung burdens were comparable to those of mice, but lung tumorigenicity was not substantiated, further raising questions about appropriate species extrapolation. Open questions also exist regarding test material chemical characterization, as the laboratory relied on vanadium measurement in test chambers as a surrogate for V2O5. In sum, the NTP V2O5 study does not provide an appropriate dataset for purposes of classification and risk assessment. Additional repeat exposure studies of vanadium compounds are needed and recommendations for future studies are provided.
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Affiliation(s)
| | - David J White
- David White Chemical and Metallurgical Consulting, Apex, NC, USA
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11
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Vincent MJ, Kozal JS, Thompson WJ, Maier A, Dotson GS, Best EA, Mundt KA. Ethylene Oxide: Cancer Evidence Integration and Dose-Response Implications. Dose Response 2019; 17:1559325819888317. [PMID: 31853235 PMCID: PMC6906442 DOI: 10.1177/1559325819888317] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 11/16/2022] Open
Abstract
The International Agency for Research on Cancer (IARC) and the United States
Environmental Protection Agency (USEPA) classified ethylene oxide (EtO) as a
known human carcinogen. Critically, both noted that the epidemiological evidence
based on lymphoid and breast cancers was “limited,” but that the evidence in
animal studies was “sufficient” and “extensive” (respectively) and that EtO is
genotoxic. The USEPA derived one of the highest published inhalation unit risk
(IUR) values (3 × 10−3 per [µg/m3 EtO]), based on results
from 2 epidemiological studies. We performed focused reviews of the
epidemiological and toxicological evidence on the carcinogenicity of EtO and
considered the USEPA’s reliance on a genotoxic mode of action to establish EtO’s
carcinogenicity and to determine likely dose–response patterns. Higher quality
epidemiological studies demonstrated no increased risk of breast cancers or
lymphohematopoietic malignancies (LHM). Similarly, toxicological studies and
studies of early effect biomarkers in animals and humans provided no strong
indication that EtO causes LHM or mammary cancers. Ultimately, animal data are
inadequate to define the actual dose–response shape or predict tumor response at
very low doses with any confidence. We conclude that the IARC and USEPA
classification of EtO as a known human carcinogen overstates the underlying
evidence and that the IUR derived by USEPA grossly overestimates risk.
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12
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Abstract
The laboratory rat, Rattus norvegicus, has been used in biomedical research for more than 150 years, and in many cases remains the model of choice for studies of physiology, behavior, and complex human disease. This book provides detailed information on a number of methodologies that can be used in rat. This chapter gives an introduction to rat as a species and as a biomedical model, providing historical information, a brief introduction to the current state of rat research, and a perspective on the future of rat as a model for human disease.
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Affiliation(s)
- Jennifer R Smith
- Department of Biomedical Engineering, Rat Genome Database, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - Elizabeth R Bolton
- Department of Biomedical Engineering, Rat Genome Database, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Melinda R Dwinell
- Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Physiology, Rat Genome Database, Medical College of Wisconsin, Milwaukee, WI, USA
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13
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FEMA GRAS assessment of natural flavor complexes: Citrus-derived flavoring ingredients. Food Chem Toxicol 2018; 124:192-218. [PMID: 30481573 DOI: 10.1016/j.fct.2018.11.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 11/19/2018] [Accepted: 11/23/2018] [Indexed: 01/06/2023]
Abstract
In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavoring ingredients. This publication is the first in a series and summarizes the evaluation of 54 Citrus-derived NFCs using the procedure outlined in Smith et al. (2005) and updated in Cohen et al. (2018) to evaluate the safety of naturally-occurring mixtures for their intended use as flavoring ingredients. The procedure relies on a complete chemical characterization of each NFC intended for commerce and organization of each NFC's chemical constituents into well-defined congeneric groups. The safety of the NFC is evaluated using the well-established and conservative threshold of toxicological concern (TTC) concept in addition to data on absorption, metabolism and toxicology of members of the congeneric groups and the NFC under evaluation. As a result of the application of the procedure, 54 natural flavor complexes derived from botanicals of the Citrus genus were affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavoring ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.
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14
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Gauvin DV, Dalton JA, Harter ML, Holdsworth D, May J, Tapp R, Zimmermann ZJ, Kilgus Q, Baird TJ. Relative equivalence of CNS safety (FOB) assessment outcomes in male and female Wistar-Han and Sprague-Dawley rats. J Pharmacol Toxicol Methods 2018; 95:2-11. [PMID: 30476622 DOI: 10.1016/j.vascn.2018.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/23/2018] [Accepted: 11/21/2018] [Indexed: 11/15/2022]
Abstract
In 2006 the National Toxicology Program (NTP) of the FDA shifted to the preferred use of Wistar-Han rats from the more commonly used Sprague-Dawley (SD) strain - and industry followed. While European laboratories preferred the Wistar-Han line, there was a paucity of relevant historical control data in many US research institutions for the new "industry standard" rat strain. In 2010 the NTP reversed its decision and shifted back to SD rats because of reproductive issues with the Wistar strain. For post hoc comparative analyses, we report minimal practical differences in Functional Observational Battery (FOB) data from a large sample of male and female Wistar-Han and SD rats. In summarizing data from the preclinical safety evaluations of the CNS effects of new drugs using the FOB, it is crucial to understand the value of not only how the functional expression of drug effects in the rat are predictive of the human response, but also how and why they differ. What we can predict from the behavioral and physiological response of the designated test system to drug administration is the foundation of "generalizability" to the human's response. Here, we conclude that the use of either SD or WH rat strains in standard CNS safety studies provide equivalent supportive data for CNS safety assessment required for IND approval under the harmonized guidelines.
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Affiliation(s)
| | | | | | | | - Jonelle May
- Safety Pharmacology Department, United States
| | - Rachel Tapp
- Neurobehavioral Sciences Department, United States
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15
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Bastaki M, Aubanel M, Bauter M, Cachet T, Demyttenaere J, Diop MM, Harman CL, Hayashi SM, Krammer G, Li X, Llewellyn C, Mendes O, Renskers KJ, Schnabel J, Smith BP, Taylor SV. Absence of renal adverse effects from β-myrcene dietary administration in OECD guideline-compliant subchronic toxicity study. Food Chem Toxicol 2018; 120:222-229. [DOI: 10.1016/j.fct.2018.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 01/22/2023]
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16
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Auerbach SS, Xu M, Merrick BA, Hoenerhoff MJ, Phadke D, Taxman DJ, Shah R, Hong HHL, Ton TV, Kovi RC, Sills RC, Pandiri AR. Exome Sequencing of Fresh-frozen or Formalin-fixed Paraffin-embedded B6C3F1/N Mouse Hepatocellular Carcinomas Arising Either Spontaneously or due to Chronic Chemical Exposure. Toxicol Pathol 2018; 46:706-718. [PMID: 30045675 DOI: 10.1177/0192623318789398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide; however, the mutational properties of HCC-associated carcinogens remain largely uncharacterized. We hypothesized that mechanisms underlying chemical-induced HCC can be characterized by evaluating the mutational spectra of these tumors. To test this hypothesis, we performed exome sequencing of B6C3F1/N HCCs that arose either spontaneously in vehicle controls ( n = 3) or due to chronic exposure to gingko biloba extract (GBE; n = 4) or methyleugenol (MEG; n = 3). Most archived tumor samples are available as formalin-fixed paraffin-embedded (FFPE) blocks, rather than fresh-frozen (FF) samples; hence, exome sequencing from paired FF and FFPE samples was compared. FF and FFPE samples showed 63% to 70% mutation concordance. Multiple known (e.g., Ctnnb1T41A, BrafV637E) and novel (e.g., Erbb4C559S, Card10A700V, and Klf11P358L) mutations in cancer-related genes were identified. The overall mutational burden was greater for MEG than for GBE or spontaneous HCC samples. To characterize the mutagenic mechanisms, we analyzed the mutational spectra in the HCCs according to their trinucleotide motifs. The MEG tumors clustered closest to Catalogue of Somatic Mutations in Cancer signatures 4 and 24, which are, respectively, associated with benzo(a)pyrene- and aflatoxin-induced HCCs in humans. These results establish a novel approach for classifying liver carcinogens and understanding the mechanisms of hepatocellular carcinogenesis.
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Affiliation(s)
- Scott S Auerbach
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Miaofei Xu
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - B Alex Merrick
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Mark J Hoenerhoff
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA.,2 Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Dhiral Phadke
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Debra J Taxman
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Ruchir Shah
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Hue-Hua L Hong
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Thai-Vu Ton
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Ramesh C Kovi
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA.,4 Experimental Pathology Laboratories Inc., Research Triangle Park, North Carolina, USA
| | - Robert C Sills
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Arun R Pandiri
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
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17
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Schmidt S. Capturing Genetic Diversity: The Power of the CC and DO Mouse Models. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:014003. [PMID: 29373858 PMCID: PMC6014709 DOI: 10.1289/ehp2385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 05/05/2023]
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18
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Hallberg LM, Ward JB, Wickliffe JK, Ameredes BT. Advanced Collaborative Emissions Study Auxiliary Findings on 2007-Compliant Diesel Engines: A Comparison With Diesel Exhaust Genotoxicity Effects Prior to 2007. ENVIRONMENTAL HEALTH INSIGHTS 2017; 11:1178630217714215. [PMID: 28659715 PMCID: PMC5479429 DOI: 10.1177/1178630217714215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
Since its beginning, more than 117 years ago, the compression-ignition engine, or diesel engine, has grown to become a critically important part of industry and transportation. Public concerns over the health effects from diesel emissions have driven the growth of regulatory development, implementation, and technological advances in emission controls. In 2001, the United States Environmental Protection Agency and California Air Resources Board issued new diesel fuel and emission standards for heavy-duty engines. To meet these stringent standards, manufacturers used new emission after-treatment technology, and modified fuel formulations, to bring about reductions in particulate matter and nitrogen oxides within the exhaust. To illustrate the impact of that technological transition, a brief overview of pre-2007 diesel engine exhaust biomarkers of genotoxicity and health-related concerns is provided, to set the context for the results of our research findings, as part of the Advanced Collaborative Emissions Study (ACES), in which the effects of a 2007-compliant diesel engine were examined. In agreement with ACES findings reported in other tissues, we observed a lack of measurable 2007-compliant diesel treatment-associated DNA damage, in lung tissue (comet assay), blood serum (8-hydroxy-2'-deoxyguanosine [8-OHdG] assay), and hippocampus (lipid peroxidation assay), across diesel exhaust exposure levels. A time-dependent assessment of 8-OHdG and lipid peroxidation also suggested no differences in responses across diesel exhaust exposure levels more than 24 months of exposure. These results indicated that the 2007-compliant diesel engine reduced measurable reactive oxygen species-associated tissue derangements and suggested that the 2007 standards-based mitigation approaches were effective.
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Affiliation(s)
- Lance M Hallberg
- Sealy Center for Environmental Health and Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Jonathan B Ward
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, USA
| | - Jeffrey K Wickliffe
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Bill T Ameredes
- Sealy Center for Environmental Health and Medicine, University of Texas Medical Branch, Galveston, TX, USA
- Division of Pulmonary Critical Care & Sleep Medicine, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA
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19
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Satyamitra M, Kumar VP, Biswas S, Cary L, Dickson L, Venkataraman S, Ghosh SP. Impact of Abbreviated Filgrastim Schedule on Survival and Hematopoietic Recovery after Irradiation in Four Mouse Strains with Different Radiosensitivity. Radiat Res 2017; 187:659-671. [PMID: 28362168 DOI: 10.1667/rr14555.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Filgrastim (Neupogen®, granulocyte-colony stimulating factor) is among the few countermeasures recommended for management of patients in the event of lethal total-body irradiation. Despite the plethora of studies using filgrastim as a radiation countermeasure, relatively little is known about the optimal dose schedule of filgrastim to mitigate radiation lethality. We evaluated the efficacy of filgrastim in improving 30-day survival of CD2F1 mice irradiated with a lethal dose (LD70/30) in the AFRRI cobalt-60 facility. We tested different schedules of 1, 3, 5, 10 or 16 once-daily injections of filgrastim initiated one day after irradiation. Time optimization studies with filgrastim treatment were also performed, beginning 6-48 h postirradiation. Maximum survival was observed with 3 daily doses of 0.17 mg/kg filgrastim. Survival efficacy of the 3-day treatment was compared against the conventional 16-day filgrastim treatment after irradiation in four mouse strains with varying radiation sensitivities: C3H/HeN, C57BL/6, B6C3F1 and CD2F1. Blood indices, bone marrow histopathology and colony forming unit assays were also evaluated. Filgrastim significantly increased 30-day survival (P < 0.001) with a 3-day treatment compared to 16-day treatment. Filgrastim did not prevent cytopenia nadirs, but facilitated faster recovery of white blood cells, neutrophils, red blood cells, platelets, lymphocytes and hematocrits in all four strains. Accelerated hematopoietic recovery was also reflected in faster bone marrow reconstitution and significant increase in hematopoietic progenitors (P < 0.001) in all four mouse strains. These data indicate that prompt and abbreviated filgrastim treatment has potential benefit for triage in the event of a radiological incident for treating acute hematopoietic syndrome.
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Affiliation(s)
- Merriline Satyamitra
- a Radiation and Nuclear Countermeasure Program, DAIT, NIAID, NIH, Bethesda, Maryland 20889
| | - Vidya P Kumar
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
| | - Shukla Biswas
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
| | - Lynnette Cary
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
| | - Leonora Dickson
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
| | - Srinivasan Venkataraman
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
| | - Sanchita P Ghosh
- b Armed Forces Radiobiology Research Institute (AFRRI), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20889
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20
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Manservisi F, Marquillas CB, Buscaroli A, Huff J, Lauriola M, Mandrioli D, Manservigi M, Panzacchi S, Silbergeld EK, Belpoggi F. An Integrated Experimental Design for the Assessment of Multiple Toxicological End Points in Rat Bioassays. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:289-295. [PMID: 27448388 PMCID: PMC5332192 DOI: 10.1289/ehp419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 04/27/2016] [Accepted: 06/20/2016] [Indexed: 05/03/2023]
Abstract
BACKGROUND For nearly five decades long-term studies in rodents have been the accepted benchmark for assessing chronic long-term toxic effects, particularly carcinogenicity, of chemicals. The European Food Safety Authority (EFSA) and the World Health Organization (WHO) have pointed out that the current set of internationally utilized test methods capture only some of the potential adverse effects associated with exposures to these agents over the lifetime. OBJECTIVES In this paper, we propose the adaption of the carcinogenicity bioassay to integrate additional protocols for comprehensive long-term toxicity assessment that includes developmental exposures and long-term outcomes, capable of generating information on a broad spectrum of different end points. DISCUSSION An integrated study design based on a stepwise process is described that includes the priority end points of the Economic Co-operation and Development and the National Toxicology Program guidelines on carcinogenicity and chronic toxicity and developmental and reproductive toxicity. Integrating a comprehensive set of relevant toxicological end points in a single protocol represents an opportunity to optimize animal use in accordance with the 3Rs (replacement, reduction and refinement). This strategy has the potential to provide sufficient data on multiple windows of susceptibility of specific interest for risk assessments and public health decision-making by including prenatal, lactational, neonatal exposures and evaluating outcomes over the lifespan. CONCLUSION This integrated study design is efficient in that the same generational cohort of rats used for evaluating long-term outcomes can be monitored in satellite parallel experiments to measure biomarkers and other parameters related to system-specific responses including metabolic alterations and endocrine disturbances. Citation: Manservisi F, Babot Marquillas C, Buscaroli A, Huff J, Lauriola M, Mandrioli D, Manservigi M, Panzacchi S, Silbergeld EK, Belpoggi F. 2017. An integrated experimental design for the assessment of multiple toxicological end points in rat bioassays. Environ Health Perspect 125:289-295; http://dx.doi.org/10.1289/EHP419.
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Affiliation(s)
- Fabiana Manservisi
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Clara Babot Marquillas
- Leonardo da Vinci Programme at the Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Annalisa Buscaroli
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - James Huff
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Michelina Lauriola
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Daniele Mandrioli
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Marco Manservigi
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Simona Panzacchi
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Ellen K. Silbergeld
- Leonardo da Vinci Programme at the Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
| | - Fiorella Belpoggi
- Cesare Maltoni Cancer Research Center, Ramazzini Institute, Bentivoglio, Bologna, Italy
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21
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Solano MDLM, Rocha NS, Barbisan LF, Franchi CADS, Spinardi-Barbisan ALT, de Oliveira MLCS, Salvadori DMF, Ribeiro LR, de Camargo JLV. Alternative Multiorgan Initiation–Promotion Assay for Chemical Carcinogenesis in the Wistar Rat. Toxicol Pathol 2016; 44:1146-1159. [DOI: 10.1177/0192623316678931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The medium-term multiorgan initiation–promotion chemical bioassay (diethylnitrosamine, methyl-nitrosourea, butyl-hydroxybutylnitrosamine, dihydroxypropylnitrosamine, dimethylhydrazine [DMBDD]) with the Fischer 344 rat was proposed as an alternative to the conventional 2-year carcinogenesis bioassay for regulatory purposes. The acronym DMBDD stands for the names of five genotoxic agents used for initiation of multiorgan carcinogenesis. The Brazilian Agency for the Environment officially recognized a variation of this assay (DMBDDb) as a valid method to assess the carcinogenic potential of agrochemicals. Different from the original protocol, this DMBDDb is 30-week long, uses Wistar rats and two positive control groups exposed to carcinogenesis promoters sodium phenobarbital (PB) or 2-acetylaminofluorene (2-AAF). This report presents the experience of an academic laboratory with the DMBDDb assay and contributes to the establishment of this alternative DMBDD bioassay in a different rat strain. Frequent lesions observed in positive groups to evaluate the promoting potential of pesticides and the immunohistochemical expressions of liver cytochrome P450 (CYP) 2B1/2B2 and CYP1A2 enzymes were assessed. Commonly affected organs were liver, kidney, intestines, urinary bladder, and thyroid. PB promoting activity was less evident than that of 2-AAF, especially in males. This study provides a repository of characteristic lesions occurring in positive control animals submitted to a modified alternative 2-stage multiorgan protocol for carcinogenesis in Wistar rat.
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Affiliation(s)
| | - Noeme Souza Rocha
- Department of Clinical Medicine, Faculty of Veterinary Medicine and Zootechnology, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | - Luis Fernando Barbisan
- Department of Morphology, Bioscience Institute, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | | | | | | | | | - Lúcia Regina Ribeiro
- Department of Pathology, Botucatu Medical School, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
| | - João Lauro Viana de Camargo
- Department of Pathology, Botucatu Medical School, UNESP—São Paulo State University, Botucatu, São Paulo, Brazil
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22
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Colman K. Impact of the Genetics and Source of Preclinical Safety Animal Models on Study Design, Results, and Interpretation. Toxicol Pathol 2016; 45:94-106. [DOI: 10.1177/0192623316672743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
It has been long established that not only the species but also the strain and supplier of rodents used in preclinical safety studies can have a significant impact on the outcome of studies due to variability in their genetic background and thus spontaneous pathologic findings. In addition, local husbandry, housing, and other environmental conditions may have effects on the development and expression of comorbidities, particularly in longer-term or chronic studies. More recently, similar effects related to the source, including genetic and environmental variability, have been recognized in cynomolgus macaques ( Macaca fascicularis). The increased use of cynomolgus macaques from various sources of captive-bred animals (including nonnative, U.S./European Union-based breeding facilities or colonies) can affect study design and study results and outcome. It is important to acknowledge and understand the impact of this variability on the results and interpretation of research studies. This review includes recent examples where variability of preclinical animal models (rats and monkeys) affected the postmortem observations highlighting its relevance to study design or interpretation in safety studies.
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Affiliation(s)
- Karyn Colman
- Novartis Pharmaceuticals Corp., East Hanover, New Jersey, USA
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23
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Zeljenková D, Aláčová R, Ondrejková J, Ambrušová K, Bartušová M, Kebis A, Kovrižnych J, Rollerová E, Szabová E, Wimmerová S, Černák M, Krivošíková Z, Kuricová M, Líšková A, Spustová V, Tulinská J, Levkut M, Révajová V, Ševčíková Z, Schmidt K, Schmidtke J, Schmidt P, La Paz JL, Corujo M, Pla M, Kleter GA, Kok EJ, Sharbati J, Bohmer M, Bohmer N, Einspanier R, Adel-Patient K, Spök A, Pöting A, Kohl C, Wilhelm R, Schiemann J, Steinberg P. One-year oral toxicity study on a genetically modified maize MON810 variety in Wistar Han RCC rats (EU 7th Framework Programme project GRACE). Arch Toxicol 2016; 90:2531-62. [PMID: 27439414 PMCID: PMC5043003 DOI: 10.1007/s00204-016-1798-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 07/06/2016] [Indexed: 12/05/2022]
Abstract
The GRACE (GMO Risk Assessment and Communication of Evidence; www.grace-fp7.eu ) project was funded by the European Commission within the 7th Framework Programme. A key objective of GRACE was to conduct 90-day animal feeding trials, animal studies with an extended time frame as well as analytical, in vitro and in silico studies on genetically modified (GM) maize in order to comparatively evaluate their use in GM plant risk assessment. In the present study, the results of a 1-year feeding trial with a GM maize MON810 variety, its near-isogenic non-GM comparator and an additional conventional maize variety are presented. The feeding trials were performed by taking into account the guidance for such studies published by the EFSA Scientific Committee in 2011 and the OECD Test Guideline 452. The results obtained show that the MON810 maize at a level of up to 33 % in the diet did not induce adverse effects in male and female Wistar Han RCC rats after a chronic exposure.
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Affiliation(s)
- Dagmar Zeljenková
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Radka Aláčová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Júlia Ondrejková
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Katarína Ambrušová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Mária Bartušová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Anton Kebis
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Jevgenij Kovrižnych
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Eva Rollerová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Elena Szabová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Soňa Wimmerová
- Faculty of Public Health, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Martin Černák
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Zora Krivošíková
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Miroslava Kuricová
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Aurélia Líšková
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Viera Spustová
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Jana Tulinská
- Faculty of Medicine, Slovak Medical University in Bratislava, Limbová 12, 83303, Bratislava, Slovakia
| | - Mikuláš Levkut
- University of Veterinary Medicine and Pharmacy in Košice and TOPALAB, Kamenicna 7, 01015, Košice, Slovakia
| | - Viera Révajová
- University of Veterinary Medicine and Pharmacy in Košice and TOPALAB, Kamenicna 7, 01015, Košice, Slovakia
| | - Zuzana Ševčíková
- University of Veterinary Medicine and Pharmacy in Košice and TOPALAB, Kamenicna 7, 01015, Košice, Slovakia
| | | | - Jörg Schmidtke
- BioMath GmbH, Schnickmannstr. 4, 18055, Rostock, Germany
| | - Paul Schmidt
- BioMath GmbH, Schnickmannstr. 4, 18055, Rostock, Germany
| | - Jose Luis La Paz
- Centre for Research in Agricultural Genomics (CRAG), Edifici CRAG, Campus UAB, 08193, Cerdanyola, Barcelona, Spain
| | - Maria Corujo
- Centre for Research in Agricultural Genomics (CRAG), Edifici CRAG, Campus UAB, 08193, Cerdanyola, Barcelona, Spain
| | - Maria Pla
- Universitat de Girona (UDG), Edifici EPS1, Campus Montilivi, 17071, Girona, Spain
| | - Gijs A Kleter
- RIKILT Wageningen UR, Wageningen University and Research Centre, Akkermaalsbos 2, 6708WB, Wageningen, The Netherlands
| | - Esther J Kok
- RIKILT Wageningen UR, Wageningen University and Research Centre, Akkermaalsbos 2, 6708WB, Wageningen, The Netherlands
| | - Jutta Sharbati
- Institute of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany
| | - Marc Bohmer
- Institute of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany
| | - Nils Bohmer
- Institute of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany
| | - Ralf Einspanier
- Institute of Veterinary Biochemistry, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany
| | - Karine Adel-Patient
- INRA, UR496 Immuno-Allergie Alimentaire, CEA/IBiTeC-S/SPI, CEA de Saclay, 91191, Gif Sur Yvette Cedex, France
| | - Armin Spök
- IFZ-Inter-University Research Centre for Technology, Work and Culture (IFZ), Schlögelgasse 2, 8010, Graz, Austria
| | - Annette Pöting
- Federal Institute for Risk Assessment, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Christian Kohl
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Ralf Wilhelm
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Joachim Schiemann
- Institute for Biosafety in Plant Biotechnology, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Pablo Steinberg
- Institute for Food Toxicology and Analytical Chemistry, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173, Hannover, Germany.
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Filgo AJ, Foley JF, Puvanesarajah S, Borde AR, Midkiff BR, Reed CE, Chappell VA, Alexander LB, Borde PR, Troester MA, Bouknight SAH, Fenton SE. Mammary Gland Evaluation in Juvenile Toxicity Studies: Temporal Developmental Patterns in the Male and Female Harlan Sprague-Dawley Rat. Toxicol Pathol 2016; 44:1034-58. [PMID: 27613106 PMCID: PMC5068132 DOI: 10.1177/0192623316663864] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
There are currently no reports describing mammary gland development in the Harlan Sprague-Dawley (HSD) rat, the current strain of choice for National Toxicology Program (NTP) testing. Our goals were to empower the NTP, contract labs, and other researchers in understanding and interpreting chemical effects in this rat strain. To delineate similarities/differences between the female and male mammary gland, data were compiled starting on embryonic day 15.5 through postnatal day 70. Mammary gland whole mounts, histology sections, and immunohistochemically stained tissues for estrogen, progesterone, and androgen receptors were evaluated in both sexes; qualitative and quantitative differences are highlighted using a comprehensive visual timeline. Research on endocrine disrupting chemicals in animal models has highlighted chemically induced mammary gland anomalies that may potentially impact human health. In order to investigate these effects within the HSD strain, 2,3,7,8-tetrachlorodibenzo-p-dioxin, diethylstilbestrol, or vehicle control was gavage dosed on gestation day 15 and 18 to demonstrate delayed, accelerated, and control mammary gland growth in offspring, respectively. We provide illustrations of normal and chemically altered mammary gland development in HSD male and female rats to help inform researchers unfamiliar with the tissue and may facilitate enhanced evaluation of both male and female mammary glands in juvenile toxicity studies.
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Affiliation(s)
- Adam J Filgo
- Curriculum in Toxicology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Julie F Foley
- Cellular and Molecular Pathology Branch, Division of the NTP, NIEHS, NIH, Research Triangle Park, North Carolina, USA
| | | | - Aditi R Borde
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Bentley R Midkiff
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Casey E Reed
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Vesna A Chappell
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Lydia B Alexander
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Pretish R Borde
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
| | - Melissa A Troester
- UNC Lineberger Comprehensive Cancer Center, Chapel Hill, North Carolina, USA Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | | | - Suzanne E Fenton
- National Toxicology Program (NTP) Laboratory, Division of the NTP, National Institute of Environmental Health Sciences (NIEHS), National Institute of Health (NIH), Research Triangle Park, North Carolina, USA
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25
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Gotardo AT, Dipe VV, Hueza IM, Górniak SL. Maternal feed restriction during pregnancy in Wistar rats: Evaluation of offspring using classical and immunoteratology protocols. Hum Exp Toxicol 2016; 36:603-615. [DOI: 10.1177/0960327116660750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Studies have revealed that impairment of the pregnant body weight reduces the fetal body weight and causes minor changes in skeletal development. The aim of the present study was to assess the effects of maternal feed restriction during pregnancy in offspring immune system development. Pregnant Wistar rats were distributed into 5 groups: 1 control in which dams received food ad libitum and 4 experimental groups in which dams were fed restricted amounts of rodent ration (16, 12, 9, or 6 g/rat/day) from the 6th to 17th gestation day. Teratogenicity was assessed using classical teratological evaluation and developmental immunotoxicology protocols. Maternal body weight gain, fetus weight, and placenta weight were reduced for feed-restricted females from the groups fed 12, 9, and 6 g/rat/day ( p < 0.05). No pup mortality was observed immediately after cesarean sections among the groups, and no visceral or skeletal malformations were detected. An immunoteratological study revealed an increase in the relative weight of the thymus and an increase in the phorbol myristate-acetate solution-induced hydrogen peroxide release by inflammatory cells in 21-day-old pups. Alterations in the delayed-type hypersensitivity response and the humoral immune response against sheep red blood cells were observed in pups from feed-restricted mothers. Feed restriction in Wistar rats during organogenesis did not promote structural malformations but resulted in offspring with lower birth weights and promoted significant changes in the immune responses of the rat pups.
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Affiliation(s)
- AT Gotardo
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, Research Centre for Veterinary Toxicology (CEPTOX), University of São Paulo, Pirassununga, SP, Brazil
| | - VV Dipe
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, Research Centre for Veterinary Toxicology (CEPTOX), University of São Paulo, Pirassununga, SP, Brazil
| | - IM Hueza
- Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo (ICAQF-UNIFESP), Campus Diadema, Diadema, Brazil
| | - SL Górniak
- Department of Pathology, School of Veterinary Medicine and Animal Sciences, Research Centre for Veterinary Toxicology (CEPTOX), University of São Paulo, Pirassununga, SP, Brazil
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Bogen KT, Heilman JM. Reassessment of MTBE cancer potency considering modes of action for MTBE and its metabolites. Crit Rev Toxicol 2016; 45 Suppl 1:1-56. [PMID: 26414780 DOI: 10.3109/10408444.2015.1052367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A 1999 California state agency cancer potency (CP) evaluation of methyl tert-butyl ether (MTBE) assumed linear risk extrapolations from tumor data were plausible because of limited evidence that MTBE or its metabolites could damage DNA, and based such extrapolations on data from rat gavage and rat and mouse inhalation studies indicating elevated tumor rates in male rat kidney, male rat Leydig interstitial cells, and female rat leukemia/lymphomas. More recent data bearing on MTBE cancer potency include a rodent cancer bioassay of MTBE in drinking water; several new studies of MTBE genotoxicity; several similar evaluations of MTBE metabolites, formaldehyde, and tert-butyl alcohol or TBA; and updated evaluations of carcinogenic mode(s) of action (MOAs) of MTBE and MTBE metabolite's. The lymphoma/leukemia data used in the California assessment were recently declared unreliable by the U.S. Environmental Protection Agency (EPA). Updated characterizations of MTBE CP, and its uncertainty, are currently needed to address a variety of decision goals concerning historical and current MTBE contamination. To this end, an extensive review of data sets bearing on MTBE and metabolite genotoxicity, cytotoxicity, and tumorigenicity was applied to reassess MTBE CP and related uncertainty in view of MOA considerations. Adopting the traditional approach that cytotoxicity-driven cancer MOAs are inoperative at very low, non-cytotoxic dose levels, it was determined that MTBE most likely does not increase cancer risk unless chronic exposures induce target-tissue toxicity, including in sensitive individuals. However, the corresponding expected (or plausible upper bound) CP for MTBE conditional on a hypothetical linear (e.g., genotoxic) MOA was estimated to be ∼2 × 10(-5) (or 0.003) per mg MTBE per kg body weight per day for adults exposed chronically over a lifetime. Based on this conservative estimate of CP, if MTBE is carcinogenic to humans, it is among the weakest 10% of chemical carcinogens evaluated by EPA.
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Maronpot RR, Nyska A, Foreman JE, Ramot Y. The legacy of the F344 rat as a cancer bioassay model (a retrospective summary of three common F344 rat neoplasms). Crit Rev Toxicol 2016; 46:641-75. [PMID: 27278595 PMCID: PMC5020328 DOI: 10.1080/10408444.2016.1174669] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Fischer 344 (F344) rat was used by the National Toxicology Program (NTP) for over 5 decades for toxicity and carcinogenicity studies. However, in 2006, the NTP decided to switch to a different rat stock due largely to high background control incidences of Leydig cell tumors (LCTs) and mononuclear cell leukemia (MNCL), also known as large granular lymphocytic (LGL) leukemia. In the current review, we aim (1) to provide a summary of NTP bioassays with treatment-associated effects involving MNCL and LCTs in addition to male F344-specific tunica vaginalis mesothelioma (TVM); (2) to describe important pathobiological differences between these F344 rat tumor responses and similar target tissue-tumor response in humans; and (3) to present the NTP reasons for switching away from the F344 rat. We show that due to the highly variable background incidence of F344 MNCL, more reliance on historical control data than is usual for most tumor responses is warranted to evaluate potential effect of any chemical treatment in this rat strain. The high spontaneous incidence of LCTs in the testes of male F344 rats has made this tumor endpoint of little practical use in identifying potential testicular carcinogenic responses. TVM responses in F344 rats have a biological plausible relationship to LCTs unlike TVM in humans. Given their high spontaneous background incidence and species-specific biology, we contend that MNCL and LCT, along with TVM responses, in F344 rat carcinogenicity studies are inappropriate tumor types for human health risk assessment and lack relevance in predicting human carcinogenicity.
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Affiliation(s)
| | - Abraham Nyska
- b Sackler School of Medicine, Tel Aviv University, and Consultant in Toxicologic Pathology , Timrat , Israel
| | | | - Yuval Ramot
- d Hadassah-Hebrew University Medical Center , Jerusalem , Israel
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Abstract
There is growing concern about the poor quality and lack of repeatability of many pre-clinical experiments involving laboratory animals. According to one estimate as much as $28 billion is wasted annually in the USA alone in such studies. A decade ago the FDA's "Critical path" white paper noted that "The traditional tools used to assess product safety-animal toxicology and outcomes from human studies-have changed little over many decades and have largely not benefited from recent gains in scientific knowledge. The inability to better assess and predict product safety leads to failures during clinical development and, occasionally, after marketing." Repeat-dose 28-days and 90-days toxicity tests in rodents have been widely used as part of a strategy to assess the safety of drugs and chemicals but their repeatability and power to detect adverse effects have not been formally evaluated.The guidelines (OECD TG 407 and 408) for these tests specify the dose levels and number of animals per dose but do not specify the strain of animals which should be used. In practice, almost all the tests are done using genetically undefined "albino" rats or mice in which the genetic variation, a major cause of inter-individual and strain variability, is unknown and uncontrolled. This chapter suggests that a better strategy would be to use small numbers of animals of several genetically defined strains of mice or rats instead of the undefined animals used at present. Inbred strains are more stable providing more repeatable data than outbred stocks. Importantly their greater phenotypic uniformity should lead to more powerful and repeatable tests. Any observed strain differences would indicate genetic variation in response to the test substance, providing key data. We suggest that the FDA and other regulators and funding organizations should support research to evaluate this alternative.
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Affiliation(s)
- Michael F W Festing
- c/o Medical Research Council Toxicology Unit, University of Leicester, Leicester, UK.
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Schulte K, Ehmcke J, Schlatt S, Boiani M, Nordhoff V. Lower total cell numbers in mouse preimplantation embryos cultured in human assisted reproductive technique (ART) media are not induced by apoptosis. Theriogenology 2015; 84:1620-30. [DOI: 10.1016/j.theriogenology.2015.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 08/10/2015] [Accepted: 08/21/2015] [Indexed: 12/23/2022]
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Festing MFW. Evidence should trump intuition by preferring inbred strains to outbred stocks in preclinical research. ILAR J 2015; 55:399-404. [PMID: 25541542 DOI: 10.1093/ilar/ilu036] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Inbred strains of mice such as C57BL and BALB/c are more widely used in published work than outbred stocks of mice such as ICR and CD-1. In contrast, outbred stocks of rats such as Wistar and Sprague-Dawley are more widely used than inbred strains such as F344 and LEW. The properties of inbred and outbred mice and rats are briefly reviewed, and it is concluded that, with some exceptions, there is a strong case for using inbred strains in most controlled experiments. This is because they are usually more uniform, so that fewer animals are usually needed to detect a specified response and they are more repeatable, because they are genetically defined (i.e., the strain can be identified using genetic markers) and less liable to genetic change. Yet many scientists continue to use outbred animals. In Daniel Kahneman's book "Thinking Fast and Slow" he explains that we can answer questions in 2 ways: "fast" by intuition or "slow" by analytical reasoning. The former method is instantaneous, requires no thought but is not evidence based. Analytical reasoning is evidence based but requires hard work, which we all avoid. He has found that "… when faced with a difficult question, we often answer an easier one instead, usually without noticing the substitution." The target question of whether to choose outbred or inbred strains in controlled experiments is a difficult one requiring knowledge of the characteristics of these strains and the principles of experimental design. A substitute question, "are humans and outbred stocks both genetically heterogeneous," is easily answered in the affirmative. It is likely that many scientists are intuitively answering the substitute question and are assuming that they have answered the target question. If so they may be using the wrong animals in their research. Nor is the fact that humans and outbred stocks are alike in being genetically heterogeneous a reason for using them. The whole concept of a "model" is that it is similar to the target in some respects but different in others. Rats and mice differ from humans in that we can control their genotype. This is a positive attribute that enormously increases their value in research. Funding organizations should support research in comparing the 2 types in real experiments.
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French JE, Gatti DM, Morgan DL, Kissling GE, Shockley KR, Knudsen GA, Shepard KG, Price HC, King D, Witt KL, Pedersen LC, Munger SC, Svenson KL, Churchill GA. Diversity Outbred Mice Identify Population-Based Exposure Thresholds and Genetic Factors that Influence Benzene-Induced Genotoxicity. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:237-45. [PMID: 25376053 PMCID: PMC4348743 DOI: 10.1289/ehp.1408202] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 10/31/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Inhalation of benzene at levels below the current exposure limit values leads to hematotoxicity in occupationally exposed workers. OBJECTIVE We sought to evaluate Diversity Outbred (DO) mice as a tool for exposure threshold assessment and to identify genetic factors that influence benzene-induced genotoxicity. METHODS We exposed male DO mice to benzene (0, 1, 10, or 100 ppm; 75 mice/exposure group) via inhalation for 28 days (6 hr/day for 5 days/week). The study was repeated using two independent cohorts of 300 animals each. We measured micronuclei frequency in reticulocytes from peripheral blood and bone marrow and applied benchmark concentration modeling to estimate exposure thresholds. We genotyped the mice and performed linkage analysis. RESULTS We observed a dose-dependent increase in benzene-induced chromosomal damage and estimated a benchmark concentration limit of 0.205 ppm benzene using DO mice. This estimate is an order of magnitude below the value estimated using B6C3F1 mice. We identified a locus on Chr 10 (31.87 Mb) that contained a pair of overexpressed sulfotransferases that were inversely correlated with genotoxicity. CONCLUSIONS The genetically diverse DO mice provided a reproducible response to benzene exposure. The DO mice display interindividual variation in toxicity response and, as such, may more accurately reflect the range of response that is observed in human populations. Studies using DO mice can localize genetic associations with high precision. The identification of sulfotransferases as candidate genes suggests that DO mice may provide additional insight into benzene-induced genotoxicity.
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Affiliation(s)
- John E French
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Resources (DHHS), Research Triangle Park, North Carolina, USA
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32
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Schmidt CW. Diversity outbred: a new generation of mouse model. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:A64-A67. [PMID: 25730842 PMCID: PMC4348734 DOI: 10.1289/ehp.123-a64] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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Foster PMD. Regulatory Forum opinion piece: New testing paradigms for reproductive and developmental toxicity--the NTP modified one generation study and OECD 443. Toxicol Pathol 2014; 42:1165-7. [PMID: 24862797 DOI: 10.1177/0192623314534920] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The National Toxicology Program (NTP) has developed a new flexible study design, termed the modified one generation (MOG) reproduction study. The MOG study will encompass measurements of developmental and reproductive toxicity parameters as well as enable the setting of appropriate dose levels for a cancer bioassay through evaluation of target organ toxicity that is based on test article exposure that starts during gestation. This study design is compared and contrasted with the new Organization for Economic Co-operation and Development (OECD) 443 test guideline, the extended one generation reproduction study. The MOG study has a number of advantages, with a focus on F 1 animals, the generation of adequately powered, robust data sets that include both pre and postnatal developmental toxicity information, and the measurement of effects on reproductive structure and function in the same animals. This new study design does not employ the use of internal triggers in the design structure for the use of animals already on test and is also consistent with the principles of the 3R's.
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Affiliation(s)
- Paul M D Foster
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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34
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Inagaki K, Koga H, Inoue K, Suzuki K, Suzuki H. Spontaneous intraocular hemorrhage in rats during postnatal ocular development. Comp Med 2014; 64:34-43. [PMID: 24512959 PMCID: PMC3929217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/26/2013] [Accepted: 08/01/2013] [Indexed: 06/03/2023]
Abstract
To study spontaneous intraocular hemorrhage in rats during postnatal ocular development and to elucidate the underlying mechanism, postnatal ocular development in the albino Wistar Hannover (WH) and Sprague-Dawley (SpD) and pigmented Long-Evans (LE) strains was analyzed. Pups (n = 2 to 5) from each strain were euthanized daily on postnatal days (PND) 0 through 21 and their eyes examined macroscopically and histologically; similar analyses were performed in 26 to 39 additional WH pups daily from PND 7 to 14. At necropsy, ring-shaped red regions and red spots were present in the eyes of WH and SpD rats. These lesions were attributed histologically to hemorrhage of the tunica vasculosa lentis or of the retina, choroid, and hyaloid artery, respectively. Similar intraocular hemorrhages occurred in LE rats, although the macroscopic alterations found in WH and SpD rats were not present in this strain. Among the 3 strains evaluated, the incidence of the intraocular hemorrhage was highest in WH rats. We here showed that intraocular hemorrhage occurs spontaneously during normal ocular development in rats regardless of the strain; however, the region, degree, and incidence of intraocular hemorrhage differ among strains. Hemorrhage in the tunica vasculosa lentis and hyaloid artery may result from the leakage of erythrocytes from the temporary vasculature of these tissues during regression. The mechanisms underlying hemorrhage in the retina and choroid remain unclear. To our knowledge, this report is the first to describe the spontaneous intraocular hemorrhage that occurs during postnatal ocular development in rats.
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Affiliation(s)
- Katsuhiro Inagaki
- Research Center, Nihon Nohyaku, Kawachi-Nagano, Osaka, Japan; Laboratory of Veterinary Physiology, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan.
| | - Hiroyasu Koga
- Research Center, Nihon Nohyaku, Kawachi-Nagano, Osaka, Japan
| | - Kazuyoshi Inoue
- Research Center, Nihon Nohyaku, Kawachi-Nagano, Osaka, Japan
| | - Katsushi Suzuki
- Laboratory of Veterinary Physiology, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan
| | - Hiroetsu Suzuki
- Laboratory of Veterinary Physiology, Nippon Veterinary and Life Science University, Musashino-shi, Tokyo, Japan
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35
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Edler L, Hart A, Greaves P, Carthew P, Coulet M, Boobis A, Williams GM, Smith B. Selection of appropriate tumour data sets for Benchmark Dose Modelling (BMD) and derivation of a Margin of Exposure (MoE) for substances that are genotoxic and carcinogenic: considerations of biological relevance of tumour type, data quality and uncertainty assessment. Food Chem Toxicol 2013; 70:264-89. [PMID: 24176677 DOI: 10.1016/j.fct.2013.10.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/17/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
Abstract
This article addresses a number of concepts related to the selection and modelling of carcinogenicity data for the calculation of a Margin of Exposure. It follows up on the recommendations put forward by the International Life Sciences Institute - European branch in 2010 on the application of the Margin of Exposure (MoE) approach to substances in food that are genotoxic and carcinogenic. The aims are to provide practical guidance on the relevance of animal tumour data for human carcinogenic hazard assessment, appropriate selection of tumour data for Benchmark Dose Modelling, and approaches for dealing with the uncertainty associated with the selection of data for modelling and, consequently, the derived Point of Departure (PoD) used to calculate the MoE. Although the concepts outlined in this article are interrelated, the background expertise needed to address each topic varies. For instance, the expertise needed to make a judgement on biological relevance of a specific tumour type is clearly different to that needed to determine the statistical uncertainty around the data used for modelling a benchmark dose. As such, each topic is dealt with separately to allow those with specialised knowledge to target key areas of guidance and provide a more in-depth discussion on each subject for those new to the concept of the Margin of Exposure approach.
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Affiliation(s)
- Lutz Edler
- German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| | - Andy Hart
- The Food and Environment Research Agency - FERA, Sand Hutton, YO41 1LZ York, United Kingdom.
| | - Peter Greaves
- Department of Cancer Studies and Molecular Medicine, University of Leicester, LE2 7LX Leicester, United Kingdom.
| | - Philip Carthew
- Unilever, Colworth House Sharnbrook, MK44 1LQ Bedfordshire, United Kingdom.
| | - Myriam Coulet
- Nestlé Research Centre, Vers-Chez-Les-Blanc, 1000 Lausanne, Switzerland.
| | - Alan Boobis
- Imperial College, Hammersmith Campus, Ducane Road, W12 0NN London, United Kingdom.
| | - Gary M Williams
- New York Medical College, Basic Science Building, Room 413, Valhalla, NY 10595, United States.
| | - Benjamin Smith
- Firmenich, Rue de la Bergere 7, 1217-Meyrin 2, Switzerland.
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36
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Comparative assessment of the timing of sexual maturation in male Wistar Han and Sprague-Dawley rats. Reprod Toxicol 2013; 38:16-24. [DOI: 10.1016/j.reprotox.2013.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 02/04/2013] [Accepted: 02/11/2013] [Indexed: 11/20/2022]
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37
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Lack of human tissue-specific correlations for rodent pancreatic and colorectal carcinogens. Regul Toxicol Pharmacol 2012; 64:442-58. [PMID: 23069141 DOI: 10.1016/j.yrtph.2012.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 09/12/2012] [Accepted: 10/01/2012] [Indexed: 12/14/2022]
Abstract
To better understand the relationships between chemical exposures and human cancer causation, incidence data for human cancer types were identified and pancreatic and colorectal cancers were studied in-depth to assess whether data supporting the causation of pancreatic or colorectal tumors by chemicals in rodents is predictive of causation by the same chemicals of the same tumors in humans. A search of the Carcinogenic Potency Database, the National Toxicology Program (NTP) technical report database, and the published literature identified 38 and 39 chemicals reported to cause pancreatic and colorectal tumors, respectively, in mice or rats. For each of these chemicals, searches were conducted of the International Agency for Research on Cancer monographs, the NTP Report on Carcinogens, and the published literature for evidence of induction of the same tumors in humans. Based on this evaluation, no conclusive evidence was identified to suggest that chemicals reported to cause pancreatic or colorectal tumors in rodents also cause these tumors in humans. These findings suggest that pancreatic tumor data from mouse and rat bioassays are of limited utility with regard to predicting similar tumor induction in humans. For colorectal cancer, a lack of correlation was noted for the vast majority of chemicals.
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McCoy A, Besch-Williford CL, Franklin CL, Weinstein EJ, Cui X. Creation and preliminary characterization of a Tp53 knockout rat. Dis Model Mech 2012; 6:269-78. [PMID: 22917926 PMCID: PMC3529357 DOI: 10.1242/dmm.009704] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The tumor suppressor TP53 plays a crucial role in cancer biology, and the TP53 gene is the most mutated gene in human cancer. Trp53 knockout mouse models have been widely used in cancer etiology studies and in search for a cure of cancer with some limitations that other model organisms might help overcome. Via pronuclear microinjection of zinc finger nucleases (ZFNs), we created a Tp53 knockout rat that contains an 11-bp deletion in exon 3, resulting in a frameshift and premature terminations in the open reading frame. In cohorts of 25 homozygous (Tp53Δ11/Δ11), 37 heterozygous (Tp53Δ11/+) and 30 wild-type rats, the Tp53Δ11/Δ11 rats lived an average of 126 days before death or removal from study because of clinical signs of abnormality or formation of tumors. Half of Tp53Δ11/+ were removed from study by 1 year of age because of tumor formation. Both Tp53Δ11/+ and Tp53Δ11/Δ11 rats developed a wide spectrum of tumors, most commonly sarcomas. Interestingly, there was a strikingly high incidence of brain lesions, especially in Tp53Δ11/Δ11 animals. We believe that this mutant rat line will be useful in studying cancer types rarely observed in mice and in carcinogenicity assays for drug development.
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Affiliation(s)
- Aaron McCoy
- Sigma Advanced Genetic Engineering Labs, Sigma-Aldrich Corporation, St Louis, MO 63146, USA
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39
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Abe M, Hayashi S, Usuda K, Hagio S, Furukawa S, Nakae D. Carcinogen-induced Thyroid Proliferative Lesions in Wistar Hannover GALAS Rats with Thyroid Dysplasia. J Toxicol Pathol 2012; 25:11-7. [PMID: 22481854 PMCID: PMC3320152 DOI: 10.1293/tox.25.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 09/08/2011] [Indexed: 12/04/2022] Open
Abstract
Incidences and morphological features of thyroid proliferative lesions induced by carcinogens in Wistar Hannover GALAS rats (GALAS rats) showing normal growth with or without thyroid dysplasia were examined. All thyroid tissue samples were obtained from our recently conducted study using male GALAS rats treated with 5 carcinogens according to the medium-term multiorgan carcinogenicity bioassay protocol (called DMBDD treatment). In the DMBDD-treated rats, thyroid dysplasia was found in 9 out of 114 rats. Follicular cell adenomas were found in 5 out of 9 rats with thyroid dysplasia and in 7 out of 105 rats without thyroid dysplasia. The incidence of adenoma was significantly increased in rats with thyroid dysplasia (55.6%) compared with that in rats without thyroid dysplasia (6.7%). Adenomas in rats with thyroid dysplasia were observed as single or multiple nodules, well demarcated and composed of variously sized vacuolated cells or unvacuolated cells. These histopathological features and staining profiles of luminal colloid for PAS and thyroglobulin, together with PCNA-positive cells, were fundamentally similar to those of rats without thyroid dysplasia. On the other hand, the luminal colloid in adenomas of rats with thyroid dysplasia had a tendency to be poorly stained for T4 compared with that of rats without thyroid dysplasia. From these findings, it appears that dysplastic thyroids of rats showing normal growth are more sensitive to carcinogens than normal thyroids. In addition, the morphological features of carcinogen-induced thyroid proliferative lesions in GALAS rats with thyroid dysplasia were fundamentally similar to those of rats without thyroid dysplasia, except for the vacuoles and T4 staining profile.
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Affiliation(s)
- Masayoshi Abe
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Industries, Ltd., 1470 Shiraoka, Minamisaitama-gun, Saitama 349-0294, Japan
| | - Seigo Hayashi
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Industries, Ltd., 1470 Shiraoka, Minamisaitama-gun, Saitama 349-0294, Japan
| | - Koji Usuda
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Industries, Ltd., 1470 Shiraoka, Minamisaitama-gun, Saitama 349-0294, Japan
| | - Soichiro Hagio
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Industries, Ltd., 1470 Shiraoka, Minamisaitama-gun, Saitama 349-0294, Japan
| | - Satoshi Furukawa
- Toxicology and Environmental Science Department, Biological Research Laboratories, Nissan Chemical Industries, Ltd., 1470 Shiraoka, Minamisaitama-gun, Saitama 349-0294, Japan
| | - Dai Nakae
- Department of Pharmaceutical Sciences, Tokyo Metropolitan Institute of Public Health, 3-24-1 Hyakunin-cho, Shinjuku, Tokyo 169-0073, Japan
- Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
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40
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McClellan RO, Hesterberg TW, Wall JC. Evaluation of carcinogenic hazard of diesel engine exhaust needs to consider revolutionary changes in diesel technology. Regul Toxicol Pharmacol 2012; 63:225-58. [DOI: 10.1016/j.yrtph.2012.04.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/07/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
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41
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Eastmond DA. Factors influencing mutagenic mode of action determinations of regulatory and advisory agencies. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2012; 751:46-63. [DOI: 10.1016/j.mrrev.2012.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/11/2012] [Accepted: 04/21/2012] [Indexed: 11/17/2022]
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42
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Boyle MC, Crabbs TA, Wyde ME, Painter JT, Hill GD, Malarkey DE, Lieuallen WG, Nyska A. Intestinal lymphangiectasis and lipidosis in rats following subchronic exposure to indole-3-carbinol via oral gavage. Toxicol Pathol 2012; 40:561-76. [PMID: 22328411 DOI: 10.1177/0192623311436178] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To investigate the toxicity and carcinogenic potential of indole-3-carbinol (I3C), the National Toxicology Program has conducted 13-week subchronic studies in Fisher 344 rats and B6C3F1 mice, and chronic 2-year bioassays in Sprague-Dawley rats and B6C3F1 mice. While the chronic study results are not yet available, subchronic study results and short-term special evaluations of interim sacrifices in the 2-year rat bioassay are presented. F344 rats were orally gavaged ≤300 mg I3C/kg body weight 5 days a week for 13 weeks. Rats treated with ≥150 mg/kg demonstrated a dose-related dilation of lymphatics (lymphangiectasis) of the duodenum, jejunum, and mesenteric lymph nodes. Material within dilated lacteals stained positively for Oil Red O and Sudan Black, consistent with lipid. Electron microscopic evaluation confirmed extracellular lipid accumulation within the villar lamina propria, lacteals, and within villar macrophages. Analyses of hepatic and pulmonary CYP1A enzymes demonstrated dose-dependent I3C induction of CYP1A1 and 1A2. B6C3F1 mice orally gavaged ≤250 mg I3C/kg body weight did not demonstrate histopathological changes; however, hepatic CYP induction was similar to that in rats. The histopathologic changes of intestinal lymphangiectasis and lipidosis in this study share similarities with intestinal lymphangiectasia as observed in humans and dogs. However, the resultant clinical spectrum of protein-losing enteropathy was not present.
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Affiliation(s)
- Michael C Boyle
- National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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43
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Okamura T, Suzuki S, Ogawa T, Kobayashi J, Kusuoka O, Hatayama K, Mochizuki M, Hoshiya T, Okazaki S, Tamura K. Background Data for General Toxicology Parameters in RccHan:WIST Rats at 8, 10, 19 and 32 Weeks of Age. J Toxicol Pathol 2012; 24:195-205. [PMID: 22319231 PMCID: PMC3266354 DOI: 10.1293/tox.24.195] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/13/2011] [Indexed: 11/24/2022] Open
Abstract
Recently, RccHanTM:WIST (Wistar Hannover) rats were introduced to toxicity
studies in Japan. The present study was performed to obtain control data for general
toxicological parameters as an aid for interpretation of results in toxicity studies using
this strain of rats. Four test groups comprising of 25 male and 25 female
RccHanTM:WIST rats were housed for 2, 4, 13 or 26 weeks from 6 weeks of age
and observed and examined for clinical observation, body weight, food consumption,
urinalysis, hematology, blood chemistry, organ weight, necropsy and/or histopathology.
Ophthalmological examination was not conducted in this study, and the data in this report
were obtained from an ongoing 104-week background study in RccHanTM:WIST rats.
These data were compared with the historical control data of CD(SD) (Sprague-Dawley)
and/or F344 (Fischer) rats. The body weights of RccHanTM:WIST rats were lower
than those of CD(SD) rats and higher than those of F344 rats. The ophthalmological
examination revealed a greater incidence of focal corneal opacity. Histopathology revealed
focal mineralization of the cornea and Berlin blue-positive pigmentation in the epididymal
interstitium as well as hepatocytes. Other than the above, some minor differences were
found in urinalysis, hematology, blood chemistry and organ weights as compared with CD(SD)
rats.
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Affiliation(s)
- Toshiya Okamura
- Gotemba Laboratory, Bozo Research Center Inc., 1284 Kamado, Gotemba-shi, Shizuoka 412-0039, Japan
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44
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Dodd D, Willson G, Parkinson H, Bermudez E. Two-year drinking water carcinogenicity study of methyl tertiary-butyl ether (MTBE) in Wistar rats. J Appl Toxicol 2011; 33:593-606. [DOI: 10.1002/jat.1776] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 01/22/2023]
Affiliation(s)
- Darol Dodd
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
| | - Gabrielle Willson
- EPL North Carolina; PO Box 12766; Research Triangle Park; NC; 27709; USA
| | - Horace Parkinson
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
| | - Edilberto Bermudez
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
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45
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A review of mammalian carcinogenicity study design and potential effects of alternate test procedures on the safety evaluation of food ingredients. Regul Toxicol Pharmacol 2011; 60:S1-34. [DOI: 10.1016/j.yrtph.2010.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/04/2010] [Indexed: 11/22/2022]
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46
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Beyer LA, Beck BD, Lewandowski TA. Historical perspective on the use of animal bioassays to predict carcinogenicity: Evolution in design and recognition of utility. Crit Rev Toxicol 2011; 41:321-38. [DOI: 10.3109/10408444.2010.541222] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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47
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Bermudez E, Willson G, Parkinson H, Dodd D. Toxicity of methyl tertiary-butyl ether (MTBE) following exposure of Wistar Rats for 13 weeks or one year via drinking water. J Appl Toxicol 2011; 32:687-706. [DOI: 10.1002/jat.1674] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/21/2010] [Accepted: 01/20/2011] [Indexed: 11/12/2022]
Affiliation(s)
- Edilberto Bermudez
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
| | - Gabrielle Willson
- EPL North Carolina; PO Box 12766; Research Triangle Park; NC; 27709; USA
| | - Horace Parkinson
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
| | - Darol Dodd
- The Hamner Institutes for Health Sciences; 6 Davis Drive; Research Triangle Park; NC; 27709-2137; USA
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48
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Bogen KT. Generic Hockey-Stick Model for Estimating Benchmark Dose and Potency: Performance Relative to BMDS and Application to Anthraquinone. Dose Response 2010; 9:182-208. [PMID: 21731536 DOI: 10.2203/dose-response.10-018.bogen] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Benchmark Dose Model software (BMDS), developed by the U.S. Environmental Protection Agency, involves a growing suite of models and decision rules now widely applied to assess noncancer and cancer risk, yet its statistical performance has never been examined systematically. As typically applied, BMDS also ignores the possibility of reduced risk at low doses ("hormesis"). A simpler, proposed Generic Hockey-Stick (GHS) model also estimates benchmark dose and potency, and additionally characterizes and tests objectively for hormetic trend. Using 100 simulated dichotomous-data sets (5 dose groups, 50 animals/group), sampled from each of seven risk functions, GHS estimators performed about as well or better than BMDS estimators, and a surprising observation was that BMDS mis-specified all of six non-hormetic sampled risk functions most or all of the time. When applied to data on rodent tumors induced by the genotoxic chemical carcinogen anthraquinone (AQ), the GHS model yielded significantly negative estimates of net potency exhibited by the combined rodent data, suggesting that-consistent with the anti-leukemogenic properties of AQ and structurally similar quinones-environmental AQ exposures do not likely increase net cancer risk. In addition to its simplicity and flexibility, the GHS approach offers a unified, consistent approach to quantifying environmental chemical risk.
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49
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Parsons BL, Myers MB, Meng F, Wang Y, McKinzie PB. Oncomutations as biomarkers of cancer risk. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:836-850. [PMID: 20740637 DOI: 10.1002/em.20600] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Cancer risk assessment impacts a range of societal needs, from the regulation of chemicals to achieving the best possible human health outcomes. Because oncogene and tumor suppressor gene mutations are necessary for the development of cancer, such mutations are ideal biomarkers to use in cancer risk assessment. Consequently, DNA-based methods to quantify particular tumor-associated hotspot point mutations (i.e., oncomutations) have been developed, including allele-specific competitive blocker-PCR (ACB-PCR). Several studies using ACB-PCR and model mutagens have demonstrated that significant induction of tumor-associated oncomutations are measureable at earlier time points than are used to score tumors in a bioassay. In the particular case of benzo[a]pyrene induction of K-Ras codon 12 TGT mutation in the A/J mouse lung, measurement of tumor-associated oncomutation was shown to be an earlier and more sensitive endpoint than tumor response. The measurement of oncomutation by ACB-PCR led to two unexpected findings. First, oncomutations are present in various tissues of control rodents and "normal" human colonic mucosa samples at relatively high frequencies. Approximately 60% of such samples (88/146) have mutant fractions (MFs) >10(-5), and some have MFs as high as 10(-3) or 10(-4). Second, preliminary data indicate that oncomutations are present frequently as subpopulations in tumors. These findings are integrated into a hypothesis that the predominant preexisting mutations in particular tissues may be useful as generic reporters of carcinogenesis. Future research opportunities using oncomutation as an endpoint are described, including rodent to human extrapolation, dose-response assessment, and personalized medicine.
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Affiliation(s)
- Barbara L Parsons
- Division of Genetic and Reproductive Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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50
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Dinse GE, Peddada SD, Harris SF, Elmore SA. Comparison of NTP historical control tumor incidence rates in female Harlan Sprague Dawley and Fischer 344/N Rats. Toxicol Pathol 2010; 38:765-75. [PMID: 20622195 DOI: 10.1177/0192623310373777] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The National Toxicology Program (NTP) has historically used Fischer 344/N (F344/N) rats for the majority of its bioassays. Recently the NTP began using the Harlan Sprague Dawley (SD) as the primary rat model for NTP studies. The NTP had previously used female SD rats in nine bioassays. This article compares historical control (HC) tumor incidence rates from these nine SD rat studies with HC tumor rates from matched NTP F344/N rat bioassays to identify similarities and differences. Matching on sex, laboratory, diet, and route led to nine comparable F344/N rat studies. Our analyses revealed statistically significant strain differences, with female SD rats having lower incidence rates for clitoral gland adenoma (0.2% vs. 5.8%) and mononuclear cell leukemia (0.9% vs. 16.7%) and higher incidence rates for mammary gland fibroadenoma (67.4% vs. 48.4%), mammary gland carcinoma (10.2% vs. 2.4%), and thyroid gland C cell adenoma (25.4% vs. 13.6%) relative to female F344/N rats. These represent five of the seven most common tumor types among female SD and F344/N rats in the NTP HC database. When vehicle was included as an additional matching criterion, the number of comparable F344/N rat studies dropped to four, but similar results were obtained.
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Affiliation(s)
- Gregg E Dinse
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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