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Wen Y, Vechetti IJ, Leng D, Alimov AP, Valentino TR, Zhang XD, McCarthy JJ, Peterson CA. Early transcriptomic signatures and biomarkers of renal damage due to prolonged exposure to embedded metal. Cell Biol Toxicol 2023; 39:2861-2880. [PMID: 37058270 DOI: 10.1007/s10565-023-09806-9] [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: 06/14/2022] [Accepted: 03/24/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Prolonged exposure to toxic heavy metals leads to deleterious health outcomes including kidney injury. Metal exposure occurs through both environmental pathways including contamination of drinking water sources and from occupational hazards, including the military-unique risks from battlefield injuries resulting in retained metal fragments from bullets and blast debris. One of the key challenges to mitigate health effects in these scenarios is to detect early insult to target organs, such as the kidney, before irreversible damage occurs. METHODS High-throughput transcriptomics (HTT) has been recently demonstrated to have high sensitivity and specificity as a rapid and cost-effective assay for detecting tissue toxicity. To better understand the molecular signature of early kidney damage, we performed RNA sequencing (RNA-seq) on renal tissue using a rat model of soft tissue-embedded metal exposure. We then performed small RNA-seq analysis on serum samples from the same animals to identify potential miRNA biomarkers of kidney damage. RESULTS We found that metals, especially lead and depleted uranium, induce oxidative damage that mainly cause dysregulated mitochondrial gene expression. Utilizing publicly available single-cell RNA-seq datasets, we demonstrate that deep learning-based cell type decomposition effectively identified cells within the kidney that were affected by metal exposure. By combining random forest feature selection and statistical methods, we further identify miRNA-423 as a promising early systemic marker of kidney injury. CONCLUSION Our data suggest that combining HTT and deep learning is a promising approach for identifying cell injury in kidney tissue. We propose miRNA-423 as a potential serum biomarker for early detection of kidney injury.
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Affiliation(s)
- Yuan Wen
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.
| | - Ivan J Vechetti
- Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Dongliang Leng
- Faculty of Health Sciences, CRDA, University of Macau, Taipa, Macau, China
| | - Alexander P Alimov
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Taylor R Valentino
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Xiaohua D Zhang
- Department of Biostatistics, College of Public Health, University of Kentucky, Lexington, KY, USA
| | - John J McCarthy
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Charlotte A Peterson
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
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2
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Moldovan OL, Vari CE, Tero-Vescan A, Cotoi OS, Cocuz IG, Tabaran FA, Pop R, Fülöp I, Chis RF, Lungu IA, Rusu A. Potential Defence Mechanisms Triggered by Monosodium Glutamate Sub-Chronic Consumption in Two-Year-Old Wistar Rats. Nutrients 2023; 15:4436. [PMID: 37892513 PMCID: PMC10610236 DOI: 10.3390/nu15204436] [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: 09/18/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Monosodium glutamate (MSG) is the sodium salt of glutamic acid (GLA), used as a flavour enhancer. MSG is considered a controversial substance. It is incriminated in disturbing the antioxidant system, but also has beneficial effects, as GLA metabolism plays a crucial role in homeostasis. This study highlights which positive or negative aspects of MSG sub-chronic consumption are better reflected in subjects potentially affected by advanced age. Daily doses of MSG were administered to four groups of two-year-old Wistar rats for 90 days: (I) 185 mg/kg bw, (II) 1500 mg/kg bw, (III) 3000 mg/kg bw and (IV) 6000 mg/kg bw, compared to a MSG non-consumer group. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, direct and total bilirubin, total cholesterol, triglycerides, creatinine and urea levels were analysed; stomach, liver and kidney samples were subjected to histopathological analysis. Although, in most cases, there were no statistical differences, interesting aspects of the dose-effect relationship were observed. After MSG sub-chronic consumption, the positive aspects of GLA seem to be reflected better than the negative ones. The hormesis effect, with low-level reactive oxygen species' protective effects and GLA metabolism, may represent the hypothesis of a potential defence mechanism triggered by MSG sub-chronic consumption in ageing rats.
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Affiliation(s)
- Octavia-Laura Moldovan
- Medicine and Pharmacy Doctoral School, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Camil-Eugen Vari
- Pharmacology and Clinical Pharmacy Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Amelia Tero-Vescan
- Medical Chemistry and Biochemistry Department, Faculty of Medicine in English, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Ovidiu Simion Cotoi
- Pathophysiology Department, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (O.S.C.); (I.G.C.)
- Pathology Department, Mures Clinical County Hospital, 540011 Targu Mures, Romania
| | - Iuliu Gabriel Cocuz
- Pathophysiology Department, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania; (O.S.C.); (I.G.C.)
- Pathology Department, Mures Clinical County Hospital, 540011 Targu Mures, Romania
| | - Flaviu Alexandru Tabaran
- Department of Pathology, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, 400372 Cluj-Napoca, Romania; (F.A.T.); (R.P.)
| | - Romelia Pop
- Department of Pathology, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, 400372 Cluj-Napoca, Romania; (F.A.T.); (R.P.)
| | - Ibolya Fülöp
- Toxicology and Biopharmacy Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Rafael Florin Chis
- Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Ioana-Andreea Lungu
- Medicine and Pharmacy Doctoral School, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
| | - Aura Rusu
- Pharmaceutical and Therapeutic Chemistry Department, Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, 540142 Targu Mures, Romania;
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3
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Gould S, Templin MV. Off target toxicities and links with physicochemical properties of medicinal products, including antibiotics, oligonucleotides, lipid nanoparticles (with cationic and/or anionic charges). Data review suggests an emerging pattern. Toxicol Lett 2023; 384:14-29. [PMID: 37454775 DOI: 10.1016/j.toxlet.2023.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Toxicology is an essential part of any drug development plan. Circumnavigating the risk of failure because of a toxicity issue can be a challenge, and failure in late development is extremely costly. To identify potential risks, it requires more than just understanding the biological target. The toxicologist needs to consider a compound's structure, it's physicochemical properties (including the impact of the overall formulation), as well as the biological target (e.g., receptor interactions). Understanding the impact of the physicochemical properties can be used to predict potential toxicities in advance by incorporating key endpoints in early screening strategies and/or used to compare toxicity profiles across lead candidates. This review discussed the risks of off-target and/or non-specific toxicities that may be associated with the physicochemical properties of compounds, especially those carrying dominant positive or negative charges, including amphiphilic small molecules, peptides, oligonucleotides and lipids/liposomes/lipid nanoparticles. The latter of which are being seen more and more in drug development, including the recent Covid pandemic, where mRNA and lipid nanoparticle technology is playing more of a role in vaccine development. The translation between non-clinical and clinical data is also considered, questioning how a physicochemical driven toxicity may be more universal across species, which means that such toxicity may be reassuringly translatable between species and as such, this information may also be considered as a support to the 3 R's, particularly in the early screening stages of a drug development plan.
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Gutsol AA, Hale TM, Thibodeau JF, Holterman CE, Nasrallah R, Correa JWN, Touyz RM, Kennedy CRJ, Burger D, Hébert RL, Burns KD. Comparative Analysis of Hypertensive Tubulopathy in Animal Models of Hypertension and Its Relevance to Human Pathology. Toxicol Pathol 2023; 51:160-175. [PMID: 37632371 DOI: 10.1177/01926233231191128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2023]
Abstract
Assessment of hypertensive tubulopathy for more than fifty animal models of hypertension in experimental pathology employs criteria that do not correspond to lesional descriptors for tubular lesions in clinical pathology. We provide a critical appraisal of experimental hypertension with the same approach used to estimate hypertensive renal tubulopathy in humans. Four models with different pathogenesis of hypertension were analyzed-chronic angiotensin (Ang) II-infused and renin-overexpressing (TTRhRen) mice, spontaneously hypertensive (SHR), and Goldblatt two-kidney one-clip (2K1C) rats. Mouse models, SHR, and the nonclipped kidney in 2K1C rats had no regular signs of hypertensive tubulopathy. Histopathology in animals was mild and limited to variations in the volume density of tubular lumen and epithelium, interstitial space, and interstitial collagen. Affected kidneys in animals demonstrated lesion values that are significantly different compared with healthy controls but correspond to mild damage if compared with hypertensive humans. The most substantial human-like hypertensive tubulopathy was detected in the clipped kidney of 2K1C rats. For the first time, our study demonstrated the regular presence of chronic progressive nephropathy (CPN) in relatively young mice and rats with induced hypertension. Because CPN may confound the assessment of rodent models of hypertension, proliferative markers should be used to verify nonhypertensive tubulopathy.
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Affiliation(s)
- Alex A Gutsol
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Taben M Hale
- The University of Arizona, Phoenix, Arizona, USA
| | | | | | | | | | | | - Chris R J Kennedy
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
| | - Dylan Burger
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
| | - Richard L Hébert
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
| | - Kevin D Burns
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- University of Ottawa, Ottawa, Ontario, Canada
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5
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Chivers JM, Whiles SA, Miles CB, Biederman BE, Ellison MF, Lovingood CW, Wright MH, Hoover DB, Raafey MA, Youngberg GA, Venkatachalam MA, Zheleznova NN, Yang C, Liu P, Kriegel AJ, Cowley AW, O'Connor PM, Picken MM, Polichnowski AJ. Brown-Norway chromosome 1 mitigates the upregulation of proinflammatory pathways in mTAL cells and subsequent age-related CKD in Dahl SS/JrHsdMcwi rats. Am J Physiol Renal Physiol 2023; 324:F193-F210. [PMID: 36475869 PMCID: PMC9886360 DOI: 10.1152/ajprenal.00145.2022] [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: 05/19/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
Chronic kidney disease (CKD) has a strong genetic component; however, the underlying pathways are not well understood. Dahl salt-sensitive (SS)/Jr rats spontaneously develop CKD with age and are used to investigate the genetic determinants of CKD. However, there are currently several genetically diverse Dahl SS rats maintained at various institutions and the extent to which some exhibit age-related CKD is unclear. We assessed glomerulosclerosis (GS) and tubulointerstitial fibrosis (TIF) in 3- and 6-mo-old male and female SS/JrHsdMcwi, BN/NHsd/Mcwi [Brown-Norway (BN)], and consomic SS-Chr 1BN/Mcwi (SS.BN1) rats, in which chromosome 1 from the BN rat was introgressed into the genome of the SS/JrHsdMcwi rat. Rats were fed a 0.4% NaCl diet. GS (31 ± 3% vs. 7 ± 1%) and TIF (2.3 ± 0.2 vs. 0.5 ± 0.1) were significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi rats, and CKD was exacerbated in males. GS was minimal in 6- and 3-mo-old BN (3.9 ± 0.6% vs. 1.2 ± 0.4%) and SS.BN1 (2.4 ± 0.5% vs. 1.0 ± 0.3%) rats, and neither exhibited TIF. In SS/JrHsdMcwi and SS.BN1 rats, mean arterial blood pressure was significantly greater in 6-mo-old compared with 3-mo-old SS/JrHsdMcwi (162 ± 4 vs. 131 ± 2 mmHg) but not SS.BN1 (115 ± 2 vs. 116 ± 1 mmHg) rats. In 6-mo-old SS/JrHsdMcwi rats, blood pressure was significantly greater in females. RNA-sequencing analysis revealed that inflammatory pathways were upregulated in isolated medullary thick ascending tubules in 7-wk-old SS/JrHsdMcwi rats, before the development of tubule pathology, compared with SS.BN1 rats. In summary, SS/JrHsdMcwi rats exhibit robust age-related progression of medullary thick ascending limb abnormalities, CKD, and hypertension, and gene(s) on chromosome 1 have a major pathogenic role in such changes.NEW & NOTEWORTHY This study shows that the robust age-related progression of kidney disease in Dahl SS/JrHsdMcw rats maintained on a normal-salt diet is abolished in consomic SS.BN1 rats. Evidence that medullary thick ascending limb segments of SS/JrHsdMcw rats are structurally abnormal and enriched in proinflammatory pathways before the development of protein casts provides new insights into the pathogenesis of kidney disease in this model.
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Affiliation(s)
- Jacqueline M Chivers
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Shannon A Whiles
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Conor B Miles
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Brianna E Biederman
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Megan F Ellison
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Connor W Lovingood
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Marie H Wright
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
| | - Donald B Hoover
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
| | - Muhammad A Raafey
- Department of Pathology, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | - George A Youngberg
- Department of Pathology, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee
| | | | | | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Pengyuan Liu
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alison J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Paul M O'Connor
- Department of Physiology, Augusta University, Augusta, Georgia
| | - Maria M Picken
- Department of Pathology, Loyola University Medical Center, Maywood, Illinois
| | - Aaron J Polichnowski
- Department of Biomedical Sciences, East Tennessee State University, Johnson City, Tennessee
- Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee
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6
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Goyenvalle A, Jimenez-Mallebrera C, van Roon W, Sewing S, Krieg AM, Arechavala-Gomeza V, Andersson P. Considerations in the Preclinical Assessment of the Safety of Antisense Oligonucleotides. Nucleic Acid Ther 2023; 33:1-16. [PMID: 36579950 PMCID: PMC9940817 DOI: 10.1089/nat.2022.0061] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The nucleic acid therapeutics field has made tremendous progress in the past decades. Continuous advances in chemistry and design have led to many successful clinical applications, eliciting even more interest from researchers including both academic groups and drug development companies. Many preclinical studies in the field focus on improving the delivery of antisense oligonucleotide drugs (ONDs) and/or assessing their efficacy in target tissues, often neglecting the evaluation of toxicity, at least in early phases of development. A series of consensus recommendations regarding regulatory considerations and expectations have been generated by the Oligonucleotide Safety Working Group and the Japanese Research Working Group for the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use S6 and Related Issues (WGS6) in several white papers. However, safety aspects should also be kept in sight in earlier phases while screening and designing OND to avoid subsequent failure in the development phase. Experts and members of the network "DARTER," a COST Action funded by the Cooperation in Science and Technology of the EU, have utilized their collective experience working with OND, as well as their insights into OND-mediated toxicities, to generate a series of consensus recommendations to assess OND toxicity in early stages of preclinical research. In the past few years, several publications have described predictive assays, which can be used to assess OND-mediated toxicity in vitro or ex vivo to filter out potential toxic candidates before moving to in vivo phases of preclinical development, that is, animal toxicity studies. These assays also have the potential to provide translational insight since they allow a safety evaluation in human in vitro systems. Yet, small preliminary in vivo studies should also be considered to complement this early assessment. In this study, we summarize the state of the art and provide guidelines and recommendations on the different tests available for these early stage preclinical assessments.
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Affiliation(s)
- Aurélie Goyenvalle
- Université Paris-Saclay, UVSQ, Inserm, END-ICAP, Versailles, France.,Address correspondence to: Aurélie Goyenvalle, PhD, Université Paris-Saclay, UVSQ, Inserm, END-ICAP, Versailles 78000, France
| | - Cecilia Jimenez-Mallebrera
- Laboratorio de Investigación Aplicada en Enfermedades Neuromusculares, Unidad de Patología Neuromuscular, Servicio de Neuropediatría, Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain.,Departamento de Genética, Microbiología y Estadística, Universitat de Barcelona, Barcelona, Spain
| | - Willeke van Roon
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - Sabine Sewing
- Pharma Research and Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Arthur M. Krieg
- RNA Therapeutics Institute, University of Massachusetts, Worcester, Massachusetts, USA
| | - Virginia Arechavala-Gomeza
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Patrik Andersson
- Safety Innovation, Safety Sciences, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Gothenburg, Sweden.,Address correspondence to: Patrik Andersson, PhD, Safety Innovation, Safety Sciences, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Pepparedsleden 1, Mölndal, Gothenburg 431 83, Sweden
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7
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Bus JS, Gollapudi BB, Hard GC. Methyl-tert-butyl ether (MTBE): integration of rat and mouse carcinogenicity data with mode of action and human and rodent bioassay dosimetry and toxicokinetics indicates MTBE is not a plausible human carcinogen. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2022; 25:135-161. [PMID: 35291916 DOI: 10.1080/10937404.2022.2041516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Methyl-tert-butyl ether (MTBE) is a fuel oxygenate used in non-United States geographies. Multiple health reviews conclude that MTBE is not a human-relevant carcinogen, and this review provides updated mode of action (MOA), exposure, dosimetry and risk perspectives supporting those conclusions. MTBE is non-genotoxic and has large margins of exposure between blood concentrations at the overall rat 400 ppm inhalation NOAEL and blood concentrations in typical workplace or general population exposures. Non-cancer and threshold cancer hazard quotients range from a high of 0.046 for fuel-pump gasoline station attendants and are 100-1,000-fold lower for general population exposures. Cancer risks conservatively assuming genotoxicity for these same scenarios are all less than 1 × 10-6. The onset of MTBE nonlinear toxicokinetics (TK) in rats at inhalation exposures less than 3,000 ppm, a dose that is also not practically achievable in fuel-use scenarios, indicates that high-dose specific male rat kidney and testes (3,000 and 8,000 ppm) and female mouse liver tumors (8000 ppm) are not quantitatively relevant to humans. Mode of action analyses also indicate MTBE male rat kidney tumors, and lesser so female mouse liver tumors, are not qualitatively relevant to humans. Thus, an integrated analysis of the toxicology, exposure/dosimetry, TK, and MOA data indicates that MTBE presents minimal human cancer and non-cancer risks.
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Affiliation(s)
- James S Bus
- Toxicology and Mechanistic Biology, Exponent Inc, Apex, NC, USA
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8
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Goyak KO, Sarang SS, Franzen A, Borghoff SJ, Ryman-Rasmussen JP. Adverse outcome pathway (AOP): α2u-globulin nephropathy and kidney tumors in male rats. Crit Rev Toxicol 2022; 52:345-357. [PMID: 35862579 DOI: 10.1080/10408444.2022.2082269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The National Research Council's vision of using adverse outcome pathways (AOPs) as a framework to assist with toxicity assessment for regulatory requirements of chemical assessment has continued to gain traction since its release in 2007. The need to expand the AOP knowledge base has gained urgency, with the U.S. Environmental Protection Agency's directive to eliminate reliance on animal toxicity testing by 2035. To meet these needs, our goal was to elucidate the AOP for male-rat-specific kidney cancer. Male-rat-specific kidney tumors occur through the ability of structurally diverse substances to induce α2u-globulin nephropathy (α2u-N), a well-studied mode of action (MoA) not relevant in humans that results in kidney tumor formation in male rats. An accepted AOP may help facilitate the differentiation from other kidney tumors MoAs. Following identification and review of relevant in vitro and in vivo literature, both the MIE and subsequent KEs were identified. Based on the weight of evidence from the various resources, the confidence in this AOP is high. Uses of this AOP include hazard identification, development of in vitro assays to determine if the MoA is through α2u-N and not relevant to humans resulting in decreased use of animals, and regulatory applications.
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Affiliation(s)
- Katy O Goyak
- ExxonMobil Biomedical Sciences, Inc., Annandale, VA, USA
| | | | - A Franzen
- ToxStrategies, Inc., Monroe, LA, USA
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9
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Phillips JA, Taub ME, Bogdanffy MS, Yuan J, Knight B, Smith JD, Ku WW. Mode of Action and Human Relevance Assessment of Male CD-1 Mouse Renal Adenocarcinoma Associated With Lifetime Exposure to Empagliflozin. J Appl Toxicol 2022; 42:1570-1584. [PMID: 35393688 DOI: 10.1002/jat.4329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 11/11/2022]
Abstract
Inhibition of sodium-glucose cotransporter-2 (SGLT2) has been shown to be a safe and efficacious approach to support managing Type 2 diabetes. In the 2-year carcinogenicity study with the SGLT2 inhibitor empagliflozin in CD-1 mice, an increased incidence of renal tubular adenomas and carcinomas was identified in the male high-dose group but was not observed in female mice. An integrated review of available nonclinical data was conducted to establish a mode-of-action hypothesis for male mouse-specific tumorigenesis. Five key events were identified through systematic analysis to form the proposed mode-of-action: (1) Background kidney pathology in CD-1 mice sensitizes the strain to (2) pharmacology-related diuretic effects associated with SGLT2 inhibition. (3) In male mice, metabolic demand increases with the formation of a sex- and species-specific empagliflozin metabolite. These features converge to (4) deplete oxidative stress handling reserve, driving (5) constitutive cellular proliferation in male CD-1 mice. The proposed mode of action requires all five key events for empagliflozin to present a carcinogenicity risk in the CD-1 mouse. Considering that empagliflozin is not genotoxic in the standard battery of genotoxicity tests, and not all five key events are present in the context of female mice, rats or humans, nor for other osmotic diuretics or other SGLT2 inhibitors, the observed male mouse renal tumors are not considered relevant to humans.
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Affiliation(s)
- Jonathan A Phillips
- Boehringer Ingelheim Pharmaceuticals, Inc., Nonclinical Drug Safety, Ridgefield, CT
| | - Mitchell E Taub
- Boehringer Ingelheim Pharmaceuticals, Inc., Drug Metabolism and Pharmacokinetics, Ridgefield, CT
| | - Matthew S Bogdanffy
- Boehringer Ingelheim Pharmaceuticals, Inc., Nonclinical Drug Safety, Ridgefield, CT
| | | | - Brian Knight
- Boehringer Ingelheim Pharmaceuticals, Inc., Nonclinical Drug Safety, Ridgefield, CT
| | - James D Smith
- Boehringer Ingelheim Pharmaceuticals, Inc., Nonclinical Drug Safety, Ridgefield, CT
| | - Warren W Ku
- Boehringer Ingelheim Pharmaceuticals, Inc., Nonclinical Drug Safety, Ridgefield, CT
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10
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White JD, Bosward KL, Norris JM, Malik R, Lindsay SA, Canfield PJ. Renal Crest Proliferative Lesions in Cats with Chronic Kidney Disease. J Comp Pathol 2021; 187:52-62. [PMID: 34503654 DOI: 10.1016/j.jcpa.2021.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 05/25/2021] [Accepted: 07/08/2021] [Indexed: 11/18/2022]
Abstract
In a histopathological study of the renal crest (RC) of kidneys of cats with chronic kidney disease (CKD), 58/90 (64%) had epithelial proliferation. Of these, 33 cats had hyperplasia of the collecting duct (CD) epithelium (CDH) alone, eight had hyperplasia of the urothelium covering the RC (RCUH), of which one had concurrent abaxial renal pelvic urothelial hyperplasia (UH), and eight had both CDH and RCUH. CDH or RCUH were present in five cats with marked dysplasia of the CD epithelium (CDD) and four cats with invasive carcinomas, which also had epithelial dysplasia. All nine cats with marked dysplasia or neoplasia of the RC also had substantially altered RC contours due to focal haemorrhage, papillary necrosis or fibrosis. Three of the carcinomas had a strong desmoplastic response. In control cats, both urothelial (RC and renal pelvis) and tubular (CD and distal tubular) cells were immunopositive for cytokeratin (CK; AE1/AE3), tubular epithelial cells were positive for vimentin (Vim) and aquaporin 2 (Aq2), while urothelial cells were positive for p63. PAX8 immunolabelling was difficult to validate. CD and UH labelling was similar to control tissue. While urothelial dysplasia had the same immunolabelling pattern as UH and control tissue, CDD was generally immunonegative for Aq2. As immunolabelling of the four carcinomas did not distinguish between tubular and urothelial origin, with three positive for both Vim and p63, all were broadly designated as RC carcinomas. Overall, proliferative epithelial lesions are common in cats with CKD and form a continuum from simple hyperplasia to neoplasia of the urothelium or CD of the RC.
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Affiliation(s)
- Joanna D White
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia.
| | - Katrina L Bosward
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
| | - Jacqueline M Norris
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
| | - Richard Malik
- Centre for Veterinary Education, Veterinary Science Conference Centre B22, University of Sydney, Sydney, New South Wales, Australia
| | - Scott A Lindsay
- School of Animal and Veterinary Sciences, Faculty of Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Paul J Canfield
- Sydney School of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
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11
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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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12
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Dekant W. Tetrahydrofuran-induced tumors in rodents are not relevant to humans: Quantitative weight of evidence analysis of mode of action information does not support classification of tetrahydrofuran as a possible human carcinogen. Regul Toxicol Pharmacol 2019; 109:104499. [DOI: 10.1016/j.yrtph.2019.104499] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 10/11/2019] [Accepted: 10/12/2019] [Indexed: 02/05/2023]
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13
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Bastaki M, Api AM, Aubanel M, Bauter M, Cachet T, Demyttenaere JCR, Diop MM, Harman CL, Hayashi SM, Krammer G, Lu V, Marone PA, Mendes O, Renskers KJ, Schnabel J, Tsang SY, Taylor SV. Dietary administration of β-caryophyllene and its epoxide to Sprague-Dawley rats for 90 days. Food Chem Toxicol 2019; 135:110876. [PMID: 31610257 DOI: 10.1016/j.fct.2019.110876] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/04/2019] [Accepted: 10/06/2019] [Indexed: 02/01/2023]
Abstract
Two independent 90-day GLP-compliant studies were conducted in Sprague-Dawley rats with β-caryophyllene or β-caryophyllene epoxide, two common flavoring and fragrance materials. Dietary concentrations of β-caryophyllene were 3500; 7000; and 21,000 ppm for males and 3500; 14,000; and 56,000 ppm for females. Dietary concentrations of β-caryophyllene epoxide were 1750; 10,500; and 21,000 ppm. There were no deaths or clinical toxicity attributable to either substance administration. Statistically significant, dose-dependent reductions in body weight, body weight gain, food consumption, and food efficiency at the highest dietary concentrations of β-caryophyllene, but not of β-caryophyllene epoxide, were attributed to palatability issues. Neither β-caryophyllene nor β-caryophyllene epoxide influenced estrus cyclicity or sperm parameters. Macroscopic and microscopic findings were primarily related to changes in the kidneys of male rats, consistent with α2u-globulin nephropathy, and in the liver of male and female rats, including hepatocyte hypertrophy at the middle and high intake levels. These changes correlated with increased absolute and relative organ weights. Since the kidney findings were a species- and sex-specific effect, the NOAEL in each study was based on hepatocyte hypertrophy at the two highest dietary concentrations and were determined to be 222 mg/kg bw/day for β-caryophyllene and 109 mg/kg bw/day for β-caryophyllene epoxide.
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Affiliation(s)
- Maria Bastaki
- International Organization of the Flavor Industry, 1101 17th Street N.W., Suite 700, Washington, DC, 20036, USA
| | - Anne Marie Api
- Research Institute for Fragrance Materials, Inc., 50 Tice Boulevard, Woodcliff Lake, NJ, 07677, USA
| | - Michel Aubanel
- Kerry Flavours France, Zl du Plan BP 82067, 63 Avenue Jean Maubert, 06131, Grasse Cedex, France
| | - Mark Bauter
- Product Safety Labs, 2394 US Highway 130, Dayton, NJ, 08810, USA
| | - Thierry Cachet
- International Organization of the Flavor Industry, Avenue des Arts 6, B-1210, Brussels, Belgium
| | | | | | - Christie L Harman
- Flavor and Extract Manufacturers Association, 1101 17th Street N.W., Suite 700, Washington, DC, 20036, USA
| | - Shim-Mo Hayashi
- Japan Flavor and Fragrance Materials Association, Sankeinihonbashi Bldg. 6F, 4-7-1 Nihonbashi-Honcho, Chuo-ku, Tokyo, 103-0023, Japan
| | - Gerhard Krammer
- Symrise AG, Muehlenfeldstrasse 1, 37603, Holzminden, Germany
| | - Vivian Lu
- International Organization of the Flavor Industry, 1101 17th Street N.W., Suite 700, Washington, DC, 20036, USA
| | - Palma Ann Marone
- Product Safety Labs, 2394 US Highway 130, Dayton, NJ, 08810, USA
| | - Odete Mendes
- Product Safety Labs, 2394 US Highway 130, Dayton, NJ, 08810, USA
| | - Kevin J Renskers
- Takasago International Corporation, 4 Volvo Drive, Rockleigh, NJ, 07647, USA
| | - Jürgen Schnabel
- Givaudan International SA, Kemptpark 50, 8310 Kemptthal, Switzerland
| | - Sai Yee Tsang
- Research Institute for Fragrance Materials, Inc., 50 Tice Boulevard, Woodcliff Lake, NJ, 07677, USA
| | - Sean V Taylor
- International Organization of the Flavor Industry, 1101 17th Street N.W., Suite 700, Washington, DC, 20036, USA.
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14
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Cohen SM, Eisenbrand G, Fukushima S, Gooderham NJ, Guengerich FP, Hecht SS, Rietjens IMCM, Bastaki M, Davidsen JM, Harman CL, McGowen MM, Taylor SV. FEMA GRAS assessment of natural flavor complexes: Mint, buchu, dill and caraway derived flavoring ingredients. Food Chem Toxicol 2019; 135:110870. [PMID: 31604112 DOI: 10.1016/j.fct.2019.110870] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/18/2019] [Accepted: 10/02/2019] [Indexed: 02/08/2023]
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 flavor ingredients. NFC flavor materials include a variety of essential oils and botanical extracts. The re-evaluation of NFCs is conducted based on a constituent-based procedure outlined in 2005 and updated in 2018 that evaluates the safety of NFCs for their intended use as flavor ingredients. This procedure is applied in the re-evaluation of the generally recognized as safe (GRAS) status of NFCs with constituent profiles that are dominated by alicyclic ketones such as menthone and carvone, secondary alcohols such as menthol and carveol, and related compounds. The FEMA Expert Panel affirmed the GRAS status of Peppermint Oil (FEMA 2848), Spearmint Oil (FEMA 3032), Spearmint Extract (FEMA 3031), Cornmint Oil (FEMA 4219), Erospicata Oil (FEMA 4777), Curly Mint Oil (FEMA 4778), Pennyroyal Oil (FEMA 2839), Buchu Leaves Oil (FEMA 2169), Caraway Oil (FEMA 2238) and Dill Oil (FEMA 2383) and determined FEMA GRAS status for Buchu Leaves Extract (FEMA 4923), Peppermint Oil, Terpeneless (FEMA 4924) and Spearmint Oil, Terpeneless (FEMA 4925).
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Affiliation(s)
- Samuel M Cohen
- Havlik-Wall Professor of Oncology, Dept. of Pathology and Microbiology, University of Nebraska Medical Center, 983135 Nebraska Medical Center, Omaha, NE, 68198-3135, USA
| | - Gerhard Eisenbrand
- Food Chemistry & Toxicology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Shoji Fukushima
- Japan Bioassay Research Center, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Nigel J Gooderham
- Dept. of Metabolism, Digestion, and Reproduction, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, United Kingdom
| | - F Peter Guengerich
- Dept. of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Dept. of Laboratory Medicine and Pathology, University of Minnesota, MMC 806, 420 Delaware St., S.E., Minneapolis, MN, 55455, USA
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Tuinlaan 5, 6703 HE, Wageningen, the Netherlands
| | - Maria Bastaki
- Flavor and Extract Manufacturers Association, 1101 17th Street NW, Suite 700, Washington, DC, 20036, USA
| | - Jeanne M Davidsen
- Flavor and Extract Manufacturers Association, 1101 17th Street NW, Suite 700, Washington, DC, 20036, USA
| | - Christie L Harman
- Flavor and Extract Manufacturers Association, 1101 17th Street NW, Suite 700, Washington, DC, 20036, USA
| | - Margaret M McGowen
- Flavor and Extract Manufacturers Association, 1101 17th Street NW, Suite 700, Washington, DC, 20036, USA
| | - Sean V Taylor
- Flavor and Extract Manufacturers Association, 1101 17th Street NW, Suite 700, Washington, DC, 20036, USA.
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15
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Obert LA, Frazier KS. Intrarenal Renin–Angiotensin System Involvement in the Pathogenesis of Chronic Progressive Nephropathy—Bridging the Informational Gap Between Disciplines. Toxicol Pathol 2019; 47:799-816. [DOI: 10.1177/0192623319861367] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronic progressive nephropathy (CPN) is the most commonly encountered spontaneous background finding in laboratory rodents. Various theories on its pathogenesis have been proposed, but there is a paucity of data regarding specific mechanisms or physiologic pathways involved in early CPN development. The current CPN mechanism of action for tumorigenesis is largely based on its associated increase in tubular cell proliferation without regard to preceding subcellular degenerative changes. Combing through the published literature from multiple biology disciplines provided insight into the preceding cellular events. Mechanistic pathways involved in the progressive age-related decline in rodent kidney function and several key inflexion points have been identified. These critical pathway factors were then connected using data from renal models from multiple rodent strains, other species, and mechanistic work in humans to form a cohesive picture of pathways and protein interactions. Abundant data linked similar renal pathologies to local events involving hypoxia (hypoxia-inducible factor 1α), altered intrarenal renin–angiotensin system (RAS), oxidative stress (nitric oxide), and pro-inflammatory pathways (transforming growth factor β), with positive feedback loops and downstream effectors amplifying the injury and promoting scarring. Intrarenal RAS alterations seem to be central to all these events and may be critical to CPN development and progression.
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16
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Hard GC, Cohen SM, Ma J, Yu F, Arnold LL, Banton MI. Histopathology re-examination of the NTP toxicity/carcinogenicity studies of tert-butyl alcohol to identify renal tumor and toxicity modes of action. Regul Toxicol Pharmacol 2018; 102:65-73. [PMID: 30590081 DOI: 10.1016/j.yrtph.2018.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/07/2018] [Accepted: 12/15/2018] [Indexed: 11/18/2022]
Abstract
Tert-butyl alcohol (TBA) targets the rat kidney following repeated exposures, including renal tubule tumors. The mode of action (MOA) of these tumors, concluded by a pathology working group, involves both alpha2u-globulin nephropathy (α2u-gN) and exacerbated chronic progressive nephropathy (CPN), but has been disputed and an undefined MOA proposed. This study further reviews the histology slides of male and female rat kidneys from the NTP drinking water 13-week toxicity and 2-year carcinogenicity studies, including the 15-month interim sacrifice group. The papillary epithelial lining alteration formerly referred to as "transitional cell hyperplasia" develops as part of advanced CPN and does not represent a separate toxicity. No changes were observed in the kidney pelvis urothelium. The only alterations in subchronic male rats involved α2u-gN and CPN, without test article-related alterations in females. Focused examination of areas of parenchyma unaffected by CPN in TBA-treated male and female rats of the chronic studies revealed no renal tubule abnormalities other than from the effects of α2u-gN and CPN. Unrelated to toxicity were spontaneous amphophilic or vacuolar tubule proliferative lesions. All observed TBA-associated non-neoplastic and neoplastic histopathological changes in the kidney can be explained by α2u-gN or enhanced CPN, neither of which are relevant to humans.
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Affiliation(s)
| | - Samuel M Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198-3135, USA; Havlik-Wall Professor of Oncology, USA.
| | - Jihyun Ma
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198-4375, USA
| | - Fang Yu
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198-4375, USA
| | - Lora L Arnold
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198-3135, USA
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17
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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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18
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Parker E, McElroy P, Picut C, Szabo K, White-Hunt S. Soy-deficient diet induces renal lesions in juvenile rats. Food Chem Toxicol 2018; 121:467-471. [PMID: 30248479 DOI: 10.1016/j.fct.2018.09.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/18/2018] [Accepted: 09/20/2018] [Indexed: 10/28/2022]
Abstract
Certified LabDiet® 5K96 Advanced Protocol™ Verified Casein Diet 10 IF (5K96) is a commercial diet low in soy isoflavones developed for use in developmental and reproductive toxicity (DART) studies, especially those designed to detect endocrine disruptors. The objective of this study was to determine the incidences and severities of 5K96-associated renal lesions in control F0 and F1 cohorts of rats fed the 5K96 diet. Kidneys from control animals of four DART studies involving Sprague-Dawley rats fed the 5K96 diet, were evaluated microscopically. Mineralization and basophilic tubules were present in high incidence/severity in males and females compared to historical controls fed conventional diets. F1 cohorts were affected to a far greater degree than F0 cohorts, and females were affected more than males. Consideration of target tissue and mode of action should be given before automatically incorporating the 5K96 diet into DART study designs, and caution should be exercised when identifying and interpreting renal toxicity in the F1 cohorts of such studies.
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Affiliation(s)
- Eli Parker
- Charles River Laboratories, Inc, 4025 Stirrup Creek Drive, Suite 150, Durham, NC, 27703, USA
| | - Pallavi McElroy
- Charles River Laboratories, Inc, 1407 George Road, Ashland, OH, 44805, USA
| | - Catherine Picut
- Charles River Laboratories, Inc, 4025 Stirrup Creek Drive, Suite 150, Durham, NC, 27703, USA.
| | - Kathleen Szabo
- Charles River Laboratories Inc, 15 Worman's Mill Court, Suite I, Frederick, MD, 21701, USA
| | - Stephanie White-Hunt
- Charles River Laboratories, Inc, 4025 Stirrup Creek Drive, Suite 150, Durham, NC, 27703, USA
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19
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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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20
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Abstract
The important renal tumors that can be induced by exposure of rats to chemical carcinogens are renal tubule tumors (RTTs) derived from tubule epithelium; renal pelvic carcinoma derived from the urothelial lining of the pelvis; renal mesenchymal tumors (RMTs) derived from the interstitial connective tissue; and nephroblastoma derived from the metanephric primordia. However, almost all of our knowledge concerning mechanisms of renal carcinogenesis in the rodent pertains to the adenomas and carcinomas originating from renal tubule epithelium. Currently, nine mechanistic pathways can be identified in either the rat or mouse following chemical exposure. These include direct DNA reactivity, indirect DNA reactivity through free radical formation, multiphase bioactivation involving glutathione conjugation, mitotic disruption, sustained cell proliferation from direct cytotoxicity, sustained cell proliferation by disruption of a physiologic process (alpha 2u-globulin nephropathy), exaggerated pharmacologic response, species-dominant metabolic pathway, and chemical exacerbation of chronic progressive nephropathy. Spontaneous occurrence of RTTs in the rat will be included since one example is a confounder for interpreting kidney tumor results in chemical carcinogenicity studies in rats.
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21
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Carrillo JC, Adenuga MD, Momin F, McKee RH. The sub-chronic toxicity of a naphthenic hydrocarbon solvent in rats. Regul Toxicol Pharmacol 2018; 95:323-332. [PMID: 29630908 DOI: 10.1016/j.yrtph.2018.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 03/06/2018] [Accepted: 04/03/2018] [Indexed: 11/19/2022]
Abstract
Cycloalkanes/naphthenes are constituents of complex hydrocarbon solvents, and hence an understanding of their toxicological profile is critical to establish safe limits for occupational exposures to these solvents. Although naphthenes are structurally related to and share a common metabolic fate with the straight and branched chain analogues, some toxicokinetic differences have been noted. The acute central nervous system response to volatile naphthenes in rodents has been shown to be slightly different compared to other alkane analogues. To determine whether these differences may extend to systemic effects with less volatile naphthenes, rats were exposed to 1500, 3000 or 6000 mg/m3 of a C9-C11 aliphatic solvent containing 70% naphthenes, for 90 days. Effects were limited to adaptive liver enlargement in both sexes and kidney toxicity in the male rat. For comparative purposes, the results from this study were compared to published reports of a complex hydrocarbon solvent with a higher proportion of volatile C5/C6 naphthenes and a mono-constituent naphthene (decahydronaphthalene). The results indicate that the systemic effects of naphthenes are similar to the straight and branched chain analogues and that the effects that are most relevant for human health evaluations of alkanes are acute central nervous system effects.
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Affiliation(s)
- Juan-Carlos Carrillo
- Shell Health, Shell International B.V., P.O. Box 162, 2501 AN, The Hague, The Netherlands.
| | - M David Adenuga
- ExxonMobil Biomedical Sciences, Inc., 1545 Route 22 E., Annandale, NJ 08801, USA
| | - Fayaz Momin
- Shell Health, Shell Oil Company, 150 N. Dairy Ashford Road, Woodcreek E276E, Houston, TX 77079, USA
| | - Richard H McKee
- ExxonMobil Biomedical Sciences, Inc., 1545 Route 22 E., Annandale, NJ 08801, USA
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22
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Souza NP, Hard GC, Arnold LL, Foster KW, Pennington KL, Cohen SM. Epithelium Lining Rat Renal Papilla: Nomenclature and Association with Chronic Progressive Nephropathy (CPN). Toxicol Pathol 2018; 46:266-272. [PMID: 29504493 DOI: 10.1177/0192623318762694] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chronic progressive nephropathy (CPN) occurs commonly in rats, more frequently and severely in males than females. High-grade CPN is characterized by increased layers of the renal papilla lining, designated as urothelial hyperplasia in the International Harmonization of Nomenclature and Diagnostic Criteria classification. However, urothelium lining the pelvis is not equivalent to the epithelium lining the papilla. To evaluate whether the epithelium lining the renal papilla is actually urothelial in nature and whether CPN-associated multicellularity represents proliferation, kidney tissues from aged rats with CPN, from rats with multicellularity of the renal papilla epithelium of either low-grade or marked severity, and from young rats with normal kidneys were analyzed and compared. Immunohistochemical staining for uroplakins (urothelial specific proteins) was negative in the papilla epithelium in all rats with multicellularity or not, indicating these cells are not urothelial. Mitotic figures were rarely observed in this epithelium, even with multicellularity. Immunohistochemical staining for Ki-67 was negative. Papilla lining cells and true urothelium differed by scanning electron microscopy. Based on these findings, we recommend that the epithelium lining the papilla not be classified as urothelial, and the CPN-associated lesion be designated as vesicular alteration of renal papilla instead of hyperplasia and distinguished in diagnostic systems from kidney pelvis urothelial hyperplasia.
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Affiliation(s)
- Nathália P Souza
- 1 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.,2 São Paulo State University (UNESP), Botucatu Medical School, Department of Pathology, Center for the Evaluation of the Environmental Impact on Human Health (TOXICAM), Botucatu, São Paulo, Brazil
| | | | - Lora L Arnold
- 1 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kirk W Foster
- 1 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Karen L Pennington
- 1 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Samuel M Cohen
- 1 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.,4 Havlik-Wall Professor of Oncology
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23
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Silano V, Bolognesi C, Castle L, Chipman K, Cravedi JP, Engel KH, Fowler P, Franz R, Grob K, Gürtler R, Husøy T, Kärenlampi S, Milana MR, Pfaff K, Riviere G, Srinivasan J, Tavares Poças MDF, Tlustos C, Wölfle D, Zorn H, Benigni R, Binderup ML, Brimer L, Marcon F, Marzin D, Mosesso P, Mulder G, Oskarsson A, Svendsen C, Anastassiadou M, Carfì M, Saarma S, Mennes W. Safety of benzophenone to be used as flavouring. EFSA J 2017; 15:e05013. [PMID: 32625332 PMCID: PMC7010149 DOI: 10.2903/j.efsa.2017.5013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Benzophenone [FL-no: 07.032] has been evaluated as a flavouring substance, in FGE.69, by the EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food in 2008. Benzophenone was evaluated also by JECFA (2011) and by IARC (2013) based on studies that were not considered in the EFSA opinion on FGE.69. Therefore, the Commission requested the CEF Panel to carry out a review of existing literature on the safety of this flavouring substance. In the framework of the evaluation of benzophenone as a food contact material, the CEF Panel established a tolerable daily intake (TDI) of 0.03 mg/kg body weight (bw) per day (2009). In the present Opinion, the Panel considered the already existing evaluations by EFSA, JECFA, IARC and available literature data on benzophenone toxicity. Moreover, new data on the use levels of benzophenone as a flavouring substance have been provided. The Panel considers that there is no concern with respect to genotoxicity. The Panel considers the endocrine activities of benzophenone and its metabolite 4-hydroxybenzophenone as weak and not directly related to the observed toxic effects including the neoplastic effects in rodents. The Panel confirms that the conservative approach taken by EFSA (2009) to derive a TDI of 0.03 mg/kg bw for benzophenone is appropriate to cover the non-neoplastic effects in the chronic toxicity studies and the neoplastic effects induced in the rodent carcinogenicity studies. The TDI is in the same order of magnitude as the chronic dietary exposure of adults and children to benzophenone (10-20 μg/kg bw per day) for the amount of added flavouring substance. The Panel considers that the calculated TDI and exposure estimate are based on conservative assumptions. The Panel concludes that there is no safety concern for benzophenone under the current condition of use as a flavouring substance.
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Becker RA, Dellarco V, Seed J, Kronenberg JM, Meek B, Foreman J, Palermo C, Kirman C, Linkov I, Schoeny R, Dourson M, Pottenger LH, Manibusan MK. Quantitative weight of evidence to assess confidence in potential modes of action. Regul Toxicol Pharmacol 2017; 86:205-220. [DOI: 10.1016/j.yrtph.2017.02.017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/17/2017] [Accepted: 02/18/2017] [Indexed: 12/31/2022]
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Nonaka M, Amakasu K, Saegusa Y, Naota M, Nishimura T, Ogawa K, Nishikawa A. Non-neoplastic lesions found only in the two-year bioassays but not in shorter toxicity studies of rats. Regul Toxicol Pharmacol 2017; 86:199-204. [PMID: 28288808 DOI: 10.1016/j.yrtph.2017.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/02/2017] [Accepted: 03/07/2017] [Indexed: 11/17/2022]
Abstract
International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) has been conducting a prospective evaluation period to validate the criteria for waiving some carcinogenicity studies in rats. Before the waiving strategy is practiced in ICH, it is crucial to elucidate whether non-neoplastic lesions are found only in 2-year rat carcinogenicity studies. To confirm possible importance of 2-year bioassays for evaluating chronic toxicity but not carcinogenicity, we retrospectively surveyed 59 pharmaceuticals approved by the Ministry of Health, Labour and Welfare (MHLW) from 2007 to 2010 in Japan for non-neoplastic lesions observed in carcinogenicity studies. Non-neoplastic histopathological lesions observed only in 2-year carcinogenicity studies but not in 6-month chronic toxicity studies using rats were compared with clinical adverse drug reactions (ADRs). Thirteen non-neoplastic lesions that may correlate with clinical ADRs were classified into three categories: Category 1, lesions not predictable from other nonclinical data except those from 2-year rat carcinogenicity studies; Category 2, lesions predictable mainly from chronic toxicity studies; Category 3, lesions predictable mainly from pharmacological actions. In the present survey, non-neoplastic lesions only found in 2-year rat carcinogenicity studies were neither significant in terms of frequency and severity nor useful for clinical risk management.
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Affiliation(s)
- Mizuho Nonaka
- Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Kouhei Amakasu
- Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Yukie Saegusa
- Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Misaki Naota
- Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Takuya Nishimura
- Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-0013, Japan
| | - Kumiko Ogawa
- Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Akiyoshi Nishikawa
- Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
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Biological relevance of effects following chronic administration of octamethylcyclotetrasiloxane (D4) in Fischer 344 rats. Toxicol Lett 2017; 279 Suppl 1:42-53. [PMID: 28109826 DOI: 10.1016/j.toxlet.2017.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/13/2017] [Accepted: 01/15/2017] [Indexed: 11/21/2022]
Abstract
Octamethylcyclotetrasiloxane (D4) is a cyclic siloxane primarily used as a monomer or intermediate in the production of silicone polymers resulting in potential exposure of workers, and potential low level inhalation or dermal exposure for consumers and the general public. Following a two-year inhalation toxicity study with D4 in rats, increases in uterine endometrial cystic hyperplasia and adenomas were observed at the highest concentration of D4 administered (700ppm). No other neoplasms were increased with D4 treatment. In addition, chronic inhalation exposure of rats to D4 induced changes in relative liver and kidney weights, and produced a chronic nephropathy. This manuscript examines the biological relevance and possible modes of action for the effects observed in the F344 rat following chronic inhalation exposure to D4. D4 is not genotoxic and appears to exert its effects through a nongenotoxic mode of action. An alteration in the estrous cycle in the aging F344 rat was the most likely mode of action for the observed uterine effects following chronic inhalation exposure. Data support the conclusion that D4 acts indirectly via a dopamine-like mechanism leading to alteration of the pituitary control of the estrous cycle in aging F344 rats with a decrease in progesterone and an increase in the estrogen/progesterone ratio most likely induced by a decrease in prolactin concentration. D4 also inhibited the pre-ovulatory LH surge causing a delay in ovulation, persistent follicles and thus a prolonged exposure to elevated estrogen in the adult Sprague Dawely rat. A lengthening of the estrous cycle in the F344 rat with an increase in endogenous estrogen was also induced by D4 inhalation. Although the mode of action responsible for induction of uterine adenomas in the female F344 rat has not been clearly confirmed, the subtlety of effects on the effects of D4 on cyclicity may prevent further assessment and definition of the mode of action. The occurrence of uterine endometrial adenoma in the rat is not relevant for human risk characterization because (1) there are differences in ovulatory cycle regulation in rats compared to humans, (2) cystic hyperplasia without atypia in women is not a cancer precursor, and (3) there is no endometrial lesion in women that is directly analogous to endometrial adenoma in the rat. The effects of D4 on liver are due to a phenobarbital-like mechanism that results in induction of cytochrome P450 and other enzymes of xenobiotic biotransformation. The liver effects are adaptive and not adverse. Kidney findings included chonic progressive nephropathy, a rat lesion that has no counterpart in the human and that should not be used in human risk assessment.
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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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Quast KW, Levine AD, Kester JE, Fordham CL. Forensic analysis of tertiary-butyl alcohol (TBA) detections in a hydrocarbon-rich groundwater basin. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:208. [PMID: 26946495 DOI: 10.1007/s10661-016-5193-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
Tertiary-butyl alcohol (TBA), a high-production volume (HPV) chemical, was sporadically detected in groundwater and coalbed methane (CBM) wells in southeastern Colorado's hydrocarbon-rich Raton Basin. TBA concentrations in shallow water wells averaged 75.1 μg/L, while detections in deeper CBM wells averaged 14.4 μg/L. The detection of TBA prompted a forensic investigation to try to identify potential sources. Historic and recent data were reviewed to determine if there was a discernable pattern of TBA occurrence. Supplemental samples from domestic water wells, monitor wells, CBM wells, surface waters, and hydraulic fracturing (HF) fluids were analyzed for TBA in conjunction with methyl tertiary-butyl ether (MTBE) and ethyl tertiary-butyl ether (ETBE), proxies for evidence of contamination from reformulated gasoline or associated oxygenates. Exploratory microbiological sampling was conducted to determine if methanotrophic organisms co-occurred with TBA in individual wells. Meaningful comparisons of historic TBA data were limited due to widely varying reporting limits. Mapping of TBA occurrence did not reveal any spatial patterns or physical associations with CBM operations or contamination plumes. Additionally, TBA was not detected in HF fluids or surface water samples. Given the widespread use of TBA in industrial and consumer products, including water well completion materials, it is likely that multiple diffuse sources exist. Exploratory data on stable isotopes, dissolved gases, and microbial profiling provide preliminary evidence that methanotrophic activity may be producing TBA from naturally occurring isobutane. Reported TBA concentrations were significantly below a conservative risk-based drinking water screening level of 8000 μg/L derived from animal toxicity data.
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Affiliation(s)
- Konrad W Quast
- Amec Foster Wheeler, 2030 Falling Waters Road, Suite 300, Knoxville, TN, 37922, USA.
| | - Audrey D Levine
- National Science Foundation and Flinders University, PO Box 576, Garrett Park, MD, 20896, USA
| | - Janet E Kester
- Newfields, LLC, 155 Cedar Lake Drive, Wentzville, MO, 63385, USA
| | - Carolyn L Fordham
- Terra Technologies Environmental Services, LLC, 2132 Augusta Drive, Evergreen, CO, 80439, USA
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Clewell AE, Béres E, Vértesi A, Glávits R, Hirka G, Endres JR, Murbach TS, Szakonyiné IP. A Comprehensive Toxicological Safety Assessment of an Extract of Olea Europaea L. Leaves (Bonolive™). Int J Toxicol 2015; 35:208-21. [PMID: 26658007 DOI: 10.1177/1091581815619764] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A battery of toxicological studies was conducted to investigate the genotoxicity and repeated-dose oral toxicity of Bonolive™, a proprietary water-soluble extract of the leaves of the olive tree (Olea europaea L.), in accordance with internationally accepted protocols. There was no evidence of mutagenicity in a bacterial reverse mutation test and in an vitro mammalian chromosomal aberration test nor was any genotoxic activity observed in an in vivo mouse micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/d. Bonolive™ did not cause mortality or toxic effects in Crl:(WI)BR Wistar rats in a 90-day repeated-dose oral toxicity study at doses of 360, 600, and 1000 mg/kg bw/d. The no observed adverse effect level in the 90-day study was 1000 mg/kg bw/d for both male and female rats, the highest dose tested.
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Affiliation(s)
- Amy E Clewell
- AIBMR Life Sciences, Inc, 4117 South Meridian, Puyallup, WA, USA
| | - Erzsébet Béres
- Toxi-Coop Toxicological Research Center, Budapest, Hungary
| | - Adél Vértesi
- Toxi-Coop Toxicological Research Center, Budapest, Hungary
| | - Róbert Glávits
- Toxi-Coop Toxicological Research Center, Budapest, Hungary
| | - Gábor Hirka
- Toxi-Coop Toxicological Research Center, Budapest, Hungary
| | - John R Endres
- AIBMR Life Sciences, Inc, 4117 South Meridian, Puyallup, WA, USA
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Borghoff S, Poet T, Green S, Davis J, Hughes B, Mensing T, Sarang S, Lynch A, Hard G. Methyl isobutyl ketone exposure-related increases in specific measures of α2u-globulin (α2u) nephropathy in male rats along with in vitro evidence of reversible protein binding. Toxicology 2015; 333:1-13. [DOI: 10.1016/j.tox.2015.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/23/2015] [Accepted: 02/10/2015] [Indexed: 11/15/2022]
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Sweeney LM, Kester JE, Kirman CR, Gentry PR, Banton MI, Bus JS, Gargas ML. Risk assessments for chronic exposure of children and prospective parents to ethylbenzene (CAS No. 100-41-4). Crit Rev Toxicol 2015; 45:662-726. [PMID: 25997510 DOI: 10.3109/10408444.2015.1046157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Potential chronic health risks for children and prospective parents exposed to ethylbenzene were evaluated in response to the Voluntary Children's Chemical Evaluation Program. Ethylbenzene exposure was found to be predominately via inhalation with recent data demonstrating continuing decreases in releases and both outdoor and indoor concentrations over the past several decades. The proportion of ethylbenzene in ambient air that is attributable to the ethylbenzene/styrene chain of commerce appears to be relatively very small, less than 0.1% based on recent relative emission estimates. Toxicity reference values were derived from the available data, with physiologically based pharmacokinetic models and benchmark dose methods used to assess dose-response relationships. An inhalation non-cancer reference concentration or RfC of 0.3 parts per million (ppm) was derived based on ototoxicity. Similarly, an oral non-cancer reference dose or RfD of 0.5 mg/kg body weight/day was derived based on liver effects. For the cancer assessment, emphasis was placed upon mode of action information. Three of four rodent tumor types were determined not to be relevant to human health. A cancer reference value of 0.48 ppm was derived based on mouse lung tumors. The risk characterization for ethylbenzene indicated that even the most highly exposed children and prospective parents are not at risk for non-cancer or cancer effects of ethylbenzene.
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Bus JS, Banton MI, Faber WD, Kirman CR, McGregor DB, Pourreau DB. Human health screening level risk assessments of tertiary-butyl acetate (TBAC): Calculated acute and chronic reference concentration (RfC) and Hazard Quotient (HQ) values based on toxicity and exposure scenario evaluations. Crit Rev Toxicol 2015; 45:142-71. [DOI: 10.3109/10408444.2014.980884] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bloch KM, Yaqoob N, Sharma S, Evans A, Aschauer L, Radford R, Jennings P, Ryan MP, van Delft JHM, Lock EA. Transcriptomic alterations induced by Monuron in rat and human renal proximal tubule cells in vitro and comparison to rat renal-cortex in vivo. Toxicol Res (Camb) 2015. [DOI: 10.1039/c4tx00113c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Monuron (1,1-dimethyl-3-(4-chlorophenyl)urea) is a widely used herbicide in developing countries although concerns have been raised about its toxicity and carcinogenicity.
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Affiliation(s)
- Katarzyna M. Bloch
- School of Pharmacy and Biomolecular Sciences
- Liverpool John Moores University
- Liverpool
- UK
| | - Noreen Yaqoob
- School of Pharmacy and Biomolecular Sciences
- Liverpool John Moores University
- Liverpool
- UK
| | - Sikander Sharma
- School of Pharmacy and Biomolecular Sciences
- Liverpool John Moores University
- Liverpool
- UK
| | - Andrew Evans
- School of Pharmacy and Biomolecular Sciences
- Liverpool John Moores University
- Liverpool
- UK
| | - Lydia Aschauer
- Division of Physiology
- Department of Physiology and Medical Physics
- Innsbruck Medical University
- Innsbruck
- Austria
| | - Robert Radford
- Renal Disease Research Group
- School of Biomolecular and Biomedical Science
- UCD Conway Institute
- University College Dublin
- Ireland
| | - Paul Jennings
- Division of Physiology
- Department of Physiology and Medical Physics
- Innsbruck Medical University
- Innsbruck
- Austria
| | - Michael P. Ryan
- Renal Disease Research Group
- School of Biomolecular and Biomedical Science
- UCD Conway Institute
- University College Dublin
- Ireland
| | - Joost H. M. van Delft
- Department of Health Risk Analyses and Toxicology
- Faculty of Health
- Medicine and Life Sciences
- Maastricht University
- Maastricht
| | - Edward A. Lock
- School of Pharmacy and Biomolecular Sciences
- Liverpool John Moores University
- Liverpool
- UK
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Berman CL, Cannon K, Cui Y, Kornbrust DJ, Lagrutta A, Sun SZ, Tepper J, Waldron G, Younis HS. Recommendations for safety pharmacology evaluations of oligonucleotide-based therapeutics. Nucleic Acid Ther 2014; 24:291-301. [PMID: 24946015 DOI: 10.1089/nat.2013.0477] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This document was prepared by the Safety Pharmacology Subcommittee of the Oligonucleotide Safety Working Group (OSWG), a group of industry and regulatory scientists involved in the development and regulation of therapeutic oligonucleotides. The mission of the Subcommittee was to develop scientific recommendations for the industry regarding the appropriate scope and strategies for safety pharmacology evaluations of oligonucleotides (ONs). These recommendations are the consensus opinion of the Subcommittee and do not necessarily reflect the current expectations of regulatory authorities. 1) Safety pharmacology testing, as described in the International Conference on Harmonisation (ICH) S7 guidance, is as applicable to ONs as it is to small molecule drugs and biotherapeutics. 2) Study design considerations for ONs are similar to those for other classes of drugs. In general, as with other therapeutics, studies should evaluate the drug product administered via the clinical route. Species selection should ideally consider relevance of the model with regard to the endpoints of interest, pharmacological responsiveness, and continuity with the nonclinical development program. 3) Evaluation of potential effects in the core battery (cardiovascular, central nervous, and respiratory systems) is recommended. In general: a. In vitro human ether-a-go-go-related gene (hERG) testing does not provide any specific value and is not warranted. b. Emphasis should be placed on in vivo evaluation of cardiovascular function, typically in nonhuman primates (NHPs). c. Due to the low level of concern, neurologic and respiratory function can be assessed concurrently with cardiovascular safety pharmacology evaluation in NHPs, within repeat-dose toxicity studies, or as stand-alone studies. In the latter case, rodents are most commonly used. 4) Other dedicated safety pharmacology studies, beyond the core battery, may have limited value for ONs. Although ONs can accumulate in the kidney and liver, evaluation of functional changes in these organs, as well as gastrointestinal (GI) and unintended "pro-inflammatory" effects, may be best evaluated during repeat-dose toxicity studies. Broad receptor- or ligand-binding profiling has not historically been informative for most ON subclasses, but may have value for investigative purposes.
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Reilly TP, Graziano MJ, Janovitz EB, Dorr TE, Fairchild C, Lee F, Chen J, Wong T, Whaley JM, Tirmenstein M. Carcinogenicity risk assessment supports the chronic safety of dapagliflozin, an inhibitor of sodium-glucose co-transporter 2, in the treatment of type 2 diabetes mellitus. Diabetes Ther 2014; 5:73-96. [PMID: 24474422 PMCID: PMC4065287 DOI: 10.1007/s13300-014-0053-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION Dapagliflozin is a selective inhibitor of the sodium-glucose co-transporter 2 (SGLT2) that increases urinary glucose excretion to reduce hyperglycemia in the treatment of type 2 diabetes mellitus. A robust carcinogenicity risk assessment was undertaken to assess the chronic safety of dapagliflozin and SGLT2 inhibition. METHODS Genotoxicity potential of dapagliflozin and its metabolites was assessed in silico, in vitro, and in vivo. Dapagliflozin was administered daily by oral gavage to mice, rats, and dogs to evaluate carcinogenicity risks, including the potential for tumor promotion. SGLT2(-/-) mice were observed to evaluate the effects of chronic glucosuria. The effects of dapagliflozin and increased glucose levels on a panel of human bladder transitional cell carcinoma (TCC) cell lines were also evaluated in vitro and in an in vivo xenograft model. RESULTS Dapagliflozin and its metabolites were not genotoxic. In CD-1 mice and Sprague-Dawley rats treated for up to 2 years at ≥100× human clinical exposures, dapagliflozin showed no differences versus controls for tumor incidence, time to onset for background tumors, or urinary bladder proliferative/preneoplastic lesions. No tumors or preneoplastic lesions were observed in dogs over 1 year at >3,000× the clinical exposure of dapagliflozin or in SGLT2(-/-) mice observed over 15 months. Transcription profiling in Zucker diabetic fatty rats showed that 5-week dapagliflozin treatment did not induce tumor promoter-associated or cell proliferation genes. Increasing concentrations of glucose, dapagliflozin, or its primary metabolite, dapagliflozin 3-O-glucuronide, did not affect in vitro TCC proliferation rates and dapagliflozin did not enhance tumor growth in nude mice heterotopically implanted with human bladder TCC cell lines. CONCLUSION A multitude of assessments of tumorigenicity risk consistently showed no effects, suggesting that selective SGLT2 inhibition and, specifically, dapagliflozin are predicted to not be associated with increased cancer risk.
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Affiliation(s)
- Timothy P Reilly
- Drug Safety Evaluation, Research and Development, Bristol-Myers Squibb, Princeton, NJ, USA,
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Da Rocha MS, Arnold LL, De Oliveira MLCS, Catalano SMI, Cardoso APF, Pontes MGN, Ferrucio B, Dodmane PR, Cohen SM, De Camargo JLV. Diuron-induced rat urinary bladder carcinogenesis: Mode of action and human relevance evaluations using the International Programme on Chemical Safety framework. Crit Rev Toxicol 2014; 44:393-406. [DOI: 10.3109/10408444.2013.877870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Melnick RL, Ward JM, Huff J. War on Carcinogens: Industry Disputes Human Relevance of Chemicals Causing Cancer in Laboratory Animals Based on Unproven Hypotheses, Using Kidney Tumors as an Example. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2013; 19:255-60. [DOI: 10.1179/1077352513z.00000000090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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The sub-chronic toxicity in rats of isoparaffinic solvents. Regul Toxicol Pharmacol 2013; 67:446-55. [DOI: 10.1016/j.yrtph.2013.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/04/2013] [Accepted: 09/06/2013] [Indexed: 02/03/2023]
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