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Chrysostomou PP, Freeman EL, Murphy MM, Pereira R, Esdaile DJ, Keohane P. A toxicological assessment of spermidine trihydrochloride produced using an engineered strain of Saccharomyces cerevisiae. Food Chem Toxicol 2024; 184:114428. [PMID: 38163454 DOI: 10.1016/j.fct.2023.114428] [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: 11/22/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Spermidine is a polyamine consumed in the diet, endogenously biosynthesized in most cells, and produced by the intestinal microbiome. A variety of foods contribute to intake of spermidine along with other polyamines. Spermidine trihydrochloride (spermidine-3HCl) of high purity can be produced using an engineered strain of Saccharomyces cerevisiae. Spermidine has a demonstrated history of safe use in the diet; however, limited information is available in the public literature to assess the potential toxicity of spermidine-3HCl. To support a safety assessment for this spermidine-3HCl as a dietary source of spermidine, authoritative guideline and good laboratory practice (GLP) compliant in vitro genotoxicity assays (bacterial reverse mutation and mammalian micronucleus assays) and a 90-day oral (dietary) toxicity study in rats were conducted with spermidine-3HCl. Spermidine-3HCl was non-genotoxic in the in vitro assays, and no adverse effects were reported in the 90-day oral toxicity study up to the highest dose tested, 12500 ppm, equivalent to 728 mg/kg bw/day for males and 829 mg/kg bw/day for females. The subchronic no observed adverse effect level (NOAEL) is 728 mg/kg bw/day.
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Affiliation(s)
- Paola P Chrysostomou
- Exponent Inc., Center for Chemical Regulation and Food Safety, 1150 Connecticut Ave, NW, Suite 1100, Washington, DC, 20036, USA.
| | - Elaine L Freeman
- Exponent Inc., Center for Chemical Regulation and Food Safety, 1150 Connecticut Ave, NW, Suite 1100, Washington, DC, 20036, USA
| | - Mary M Murphy
- Exponent Inc., Center for Chemical Regulation and Food Safety, 1150 Connecticut Ave, NW, Suite 1100, Washington, DC, 20036, USA
| | - Rui Pereira
- Chrysea Labs Lda, Parque Tecnológico de Cantanhede Nucleo 4 Lote 2, 3060-197, Cantanhede, Portugal
| | - David J Esdaile
- Charles River Laboratories Hungary, Kft. H-8200 Veszprém, Szabadságpuszta, Hrsz. 028/1., Hungary
| | - Patrick Keohane
- Chrysea Labs Lda, Parque Tecnológico de Cantanhede Nucleo 4 Lote 2, 3060-197, Cantanhede, Portugal
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2
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Dziwenka M, Dolan LC, Rao M. Safety of Elixinol Hemp Extract: In Vitro Genetic Toxicity and Subchronic Toxicity in Rats. J Toxicol 2023; 2023:5982883. [PMID: 38111631 PMCID: PMC10727801 DOI: 10.1155/2023/5982883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/03/2023] [Accepted: 11/25/2023] [Indexed: 12/20/2023] Open
Abstract
The results of safety studies performed with Elixinol Hemp Extract, a blend of hemp extract, cannabidiol (CBD) isolate, and copaiba containing approximately 65% total CBD, are described in this paper. In a 15-day range-finding study in rats, there were no effects of treatment with up to 101.4 mg/kg bw/day of the extract by gavage on any safety parameter measured in the study, with the exception that centrilobular hepatocellular hypertrophy occurred in all treatment groups, which correlated with increases in absolute liver weight in high-dose females and liver to terminal body weight ratio in mid-dose and high-dose females. A GLP-compliant 90-day OECD Guideline 408 study in rats that included a behavioral battery and a 28-day recovery phase was also conducted with Elixinol Hemp Extract administered by gavage. The doses used in the 90-day study were 0 (vehicle), 28.94, 50.64, and 86.81 mg/kg bw/day. The findings were similar to those observed in the range-finding study. There were no effects of the test material on any test parameter in the 90-day study other than findings related to the liver (increased liver weight in high-dose main study males and mid-dose and high-dose main study females and low incidences of hepatocellular hypertrophy and vacuolation in main study high-dose males). Similar findings were not observed in the recovery animals, and there were no alterations in the clinical chemistry suggestive of liver toxicity in any of the main study or recovery animals. Therefore, the liver outcomes observed in the main study were not considered adverse. The test material also tested negative for mutagenicity in bacterial reverse mutation assays (plate incorporation and preincubation) in the absence and presence of metabolic activation. The results indicate that the oral 90-day no observed adverse effect level (NOAEL) of Elixinol Hemp Extract in rats is 86.81 mg/kg bw/day (highest dose administered), and that the extract is not mutagenic.
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Affiliation(s)
- Margitta Dziwenka
- GRAS Associates, LLC 11810 Grand Park Avenue, Suite 500, North Bethesda, MD 20852, USA
| | - Laurie C. Dolan
- GRAS Associates, LLC 11810 Grand Park Avenue, Suite 500, North Bethesda, MD 20852, USA
| | - Mithila Rao
- Product Safety Labs, 2394 US Highway 130, Dayton, NJ 08810, USA
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3
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Clewell A, Glávits R, Endres JR, Murbach TS, Báldi PT, Renkecz T, Hirka G, Vértesi A, Béres E, Szakonyiné IP. An evaluation of the genotoxicity and 90-day repeated-dose toxicity of a CBD-rich hemp oil. J Appl Toxicol 2023; 43:1719-1747. [PMID: 37501578 DOI: 10.1002/jat.4511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/13/2023] [Accepted: 06/17/2023] [Indexed: 07/29/2023]
Abstract
Currently, there is much interest in the sales and study of consumable Cannabis sativa L. products that contain relatively high levels of cannabidiol (CBD) and low levels of Δ-9-tetrahydrocannabinol. While there are published safety evaluations for extracts containing low concentrations of CBD, toxicological assessments for those with higher concentrations are still scant in the public domain. In this paper, genotoxicity tests and a 90-day repeated-dose toxicity study of an ethanolic extract of C. sativa containing ~85% CBD were performed following relevant OECD guidelines. No increased gene mutations were observed in a bacterial reverse mutation assay compared to controls up to the maximum recommended concentration of the guideline. An in vitro chromosomal aberration assay showed no positive findings in the short-term (3 h) treatment assays. Long-term treatment (20 h) showed an increased number of cells containing aberrations at the highest dose of 2 μg/mL, which was outside of historical control levels, but not statistically significantly different from the controls. An in vivo micronucleus study showed no genotoxic potential of the test item in mice. A 90-day repeated-dose gavage study using 0, 75, 125, and 175 mg/kg bw/day showed several slight findings that were considered likely to be related to an adaptive response to consumption of the extract by the animals but were not considered toxicologically relevant. These included increases in liver and adrenal weights compared to controls. The NOAEL was determined as 175 mg/kg bw/day, the highest dose tested (equivalent to approximately 150 mg/kg bw/day of CBD).
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Affiliation(s)
- Amy Clewell
- AIBMR Life Sciences, Inc., Seattle, Washington, 98122, USA
| | | | - John R Endres
- AIBMR Life Sciences, Inc., Seattle, Washington, 98122, USA
| | | | | | | | - Gábor Hirka
- Toxi-Coop Zrt., Budapest, Hungary
- Toxi-Coop Zrt., Balatonfüred, Hungary
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4
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Poland CA, Duffin R, Weber K, Dekant W, Borm PJA. Is Pulmonary Inflammation a Valid Predictor of Particle Induced Lung Pathology? The Case of Amorphous and Crystalline silicas. Toxicol Lett 2023:S0378-4274(23)00226-6. [PMID: 37454774 DOI: 10.1016/j.toxlet.2023.07.012] [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: 01/25/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Although inflammation is a normal and beneficial response, it is also a key event in the pathology of many chronic diseases, including pulmonary and systemic particle-induced disease. In addition, inflammation is now considered as the key response in standard settings for inhaled particles and a critical endpoint in OECD-based sub-acute/ chronic animal inhalation testing protocols. In this paper, we discuss that whilst the role of inflammation in lung disease is undeniable, it is when inflammation deviates from normal parameters that adversity occurs. We introduce the importance of the time course and in particular, the reversibility of inflammation in the progression towards tissue remodelling and neoplastic changes as commonly seen in rat inhalation studies. For this purpose, we used chronic inhalation studies with synthetic amorphous silicas (SAS) and reactive crystalline silica (RCS) as a source of data to describe the time-course of inflammation towards and beyond adversity. Whilst amorphous silicas induce an acute but reversible inflammatory response, only RCS induces a persistent, progressive response after cessation of exposure, resulting in fibrosis and carcinogenicity in rodents and humans. This suggests that the use of inflammation as a fixed endpoint at the cessation of exposure may not be a reliable predictor of particle-induced lung pathology. We therefore suggest extending the current OECD testing guidelines with a recovery period, that allows inflammation to resolve or progress into altered structure and function, such as fibrosis.
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Affiliation(s)
- Craig A Poland
- Regulatory Compliance Limited, 6 Dryden Road, Loanhead, Midlothian, EH20 9TY, UK; Centre for Inflammation Research, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Rodger Duffin
- Centre for Inflammation Research, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Klaus Weber
- AnaPath Services GmbH, Hammerstrasse 49, 4410 Liestal/Switzerland
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5
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Papenfuss TL, Himmel L, Kuper CF, Mohanan S, Harleman J, Elmore SA. Toxicologic Pathology Forum: Considerations Regarding Determination of Adversity for Immunopathology Findings in Nonclinical Toxicology Studies with Immune-Modulating Therapeutics. Toxicol Pathol 2023; 51:205-215. [PMID: 37578155 DOI: 10.1177/01926233231190382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The evaluation of changes in the immune system serves to determine the efficacy and potential immunotoxicologic effects of new products under development. Toxicologic pathologists play critical roles in identifying immune system changes that drive the immunosafety determination. Standard pathology evaluations of therapies and chemicals remain similar; however, biopharmaceutical therapies have moved from simply affecting the immune system to being specifically developed to modify the immune system, which can impact interpretation. Recent explosive growth in immunomodulatory therapies presents a challenge to the toxicologic pathologist, toxicologist, and regulatory reviewer in terms of evaluating the clinical relevance and potential adversity of immune system changes. Beyond the recognition of such changes, there is an increasing expectation to evaluate, describe, and interpret how therapies affect complex immune system pathways for both immunomodulatory therapies and non-immunomodulatory drugs with off-target immunotoxic effects. In this opinion piece, considerations regarding immune system evaluation, the current landscape of immunomodulatory therapies, a brief description of immunotoxicologic (and immunopathologic) endpoints, the importance of integrating such immunosafety data, and relevance to adversity determination are discussed. Importantly, we describe how the current paradigm of determining adversity for immune system changes may be challenging or insufficient and propose a harmonized and flexible approach for assessing adversity.
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Isola AL, Carrillo JC, Lemaire P, Niemelä H, Steneholm A. Lack of human-relevant adversity of MOSH retained in tissues: Analysis of adversity and implications for regulatory assessment. Regul Toxicol Pharmacol 2022; 137:105284. [PMID: 36402242 DOI: 10.1016/j.yrtph.2022.105284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 10/27/2022] [Accepted: 11/04/2022] [Indexed: 11/18/2022]
Abstract
Mineral oils (food grade white oil or liquid paraffin) have historically been safely used in a number of sensitive end-uses, including pharmaceutical, cosmetic and food. Recent concern that certain mineral hydrocarbons (branched and cyclo-alkanes) may accumulate in human tissues has prevented European Food Safety Authority (EFSA) from deriving guidance values for food exposures. Analysis of human and animal tissue indicate that an unresolved cloud of mostly highly branched alkanes and alkylated cycloalkanes within the C20-C35 range is consistently present in all tissues. This critical review thoroughly assesses the retention of "mineral oil saturated hydrocarbons" (MOSH) in human and animal tissues and evaluates if the presence of MOSH is considered adverse and appropriate to use for risk assessment, generation of guidance values for food exposure and/or generation of derivation of health-based guidance values. An adversity framework was utilized to perform an in-depth weight of the evidence analysis, and it was concluded that mere presence of MOSH does not translate to hazard identification, and is not considered adverse. In light of this conclusion, it would not be appropriate to utilize this endpoint as the point of departure to calculate a health guidance value.
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Affiliation(s)
- A L Isola
- ExxonMobil Biomedical Sciences, Inc., 1545 US Highway 22 East, Annandale, NJ, 08801-3059, USA; CONCAWE Mineral Hydrocarbon Task Force Member, Boulevard du Souverain 165, B-1160, Brussels, Belgium.
| | - J C Carrillo
- Shell Global Solutions International B.V., PO Box 162, 2051, AN, The Hague, the Netherlands; CONCAWE Mineral Hydrocarbon Task Force Member, Boulevard du Souverain 165, B-1160, Brussels, Belgium
| | - P Lemaire
- Total Fluides, 24 Cours Michelet-La Défense 10, F-92069, Paris La Défense Cedex, France; CONCAWE Mineral Hydrocarbon Task Force Member, Boulevard du Souverain 165, B-1160, Brussels, Belgium
| | - H Niemelä
- CONCAWE Mineral Hydrocarbon Task Force Member, Boulevard du Souverain 165, B-1160, Brussels, Belgium.
| | - A Steneholm
- Nynas AB, PO Box 10 700, SE-121 29, Stockholm, Sweden; CONCAWE Mineral Hydrocarbon Task Force Member, Boulevard du Souverain 165, B-1160, Brussels, Belgium
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Kale VP, Bebenek I, Ghantous H, Kapeghian J, Singh BP, Thomas LJ. Practical Considerations in Determining Adversity and the No-Observed-Adverse-Effect-Level (NOAEL) in Nonclinical Safety Studies: Challenges, Perspectives and Case Studies. Int J Toxicol 2022; 41:143-162. [PMID: 35230174 DOI: 10.1177/10915818211073047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Determining the adverse nature of findings from nonclinical safety studies often poses a challenge for the key stakeholders responsible for interpreting the results of definitive toxicity studies in support of pharmaceutical product development. Although there are instances in which responses to treatment clearly indicate intolerability or tissue injury associated with dysfunction; in practice, more often there is uncertainty in characterizing an effect of drug treatment as adverse or not. This is due to the inherent variability in responses of biological test systems to toxicological insults, leaving the ultimate analyses of adversity to individual interpretation and subjectivity. This article is a follow-up to the workshop entitled, "Adverse or Not Adverse?: Thinking process behind adversity determination during nonclinical drug development," conducted at the 58th Annual Meeting of the Society of Toxicology, March 2019 in Baltimore, MD. In this paper, we further discuss and incorporate the perspectives of authors representing different roles, such as Study Director, Study Pathologist, Pharmacology/Toxicology Reviewer (U.S. Food and Drug Administration), and Sponsor in the determination and use of adversity. We also present a practical stepwise approach as an aid in this assessment, and further apply these principles to discuss 10 case studies with different therapeutic modalities and unique challenges.
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Affiliation(s)
| | - Ilona Bebenek
- Food and Drug Administration, Silver Spring, MD, USA
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8
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Ramot Y, Steiner M, Lavie Y, Ezov N, Laub O, Cohen E, Schwartz Y, Nyska A. Safety and efficacy of sFilm-FS, a novel biodegradable fibrin sealant, in Göttingen minipigs. J Toxicol Pathol 2021; 34:319-330. [PMID: 34629733 PMCID: PMC8484930 DOI: 10.1293/tox.2021-0030] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/02/2021] [Indexed: 11/19/2022] Open
Abstract
Bleeding during surgical procedures is a common complication. Therefore, hemostatic
agents have been developed to control bleeding, and fibrin sealants have several benefits.
sFilm-FS is a novel fibrin sealant that comprises a biodegradable co-polymeric film
embedded with human fibrinogen and thrombin. Herein, the safety and efficacy of sFilm-FS
were compared using a liver and spleen puncture model of Göttingen minipigs with those of
the standard hemostatic techniques (control animals) and EVARREST®, a reference
fibrin sealant. Hemostasis and reduced blood loss were more effectively achieved with
sFilm-FS than with the standard techniques in the control animals and comparable to those
achieved with EVARREST®. No treatment-related adverse effects were observed in
any of the groups. Histopathological evaluation indicated that sFilm-FS was slightly and
moderately reactive at the liver puncture site and spleen, respectively, compared with the
standard techniques in the control animals. These changes are expected degradation
reactions of the co-polymeric film and are not considered as adverse events. No
treatment-related abnormalities were noted in the other evaluated organs. Additionally, no
evidence of local or systemic thromboses was noted. These results support the use of
sFilm-FS for hemostasis in humans.
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Affiliation(s)
- Yuval Ramot
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Dermatology, Hadassah Medical Center, Jerusalem, 91120, Israel
| | | | - Yossi Lavie
- Envigo CRS (Israel), Ness Ziona, 7403617, Israel
| | - Nati Ezov
- Envigo CRS (Israel), Ness Ziona, 7403617, Israel
| | - Orgad Laub
- Sealantium Medical, Afek Industrial Area, P.O.B. 11817, Rosh Ha'Ayin, 4809239, Israel
| | - Eran Cohen
- Sealantium Medical, Afek Industrial Area, P.O.B. 11817, Rosh Ha'Ayin, 4809239, Israel
| | - Yotam Schwartz
- Sealantium Medical, Afek Industrial Area, P.O.B. 11817, Rosh Ha'Ayin, 4809239, Israel
| | - Abraham Nyska
- Consultant in Toxicologic Pathology, Yehuda HaMaccabi 31, floor 5, Tel Aviv, 6200515, Israel.,Tel Aviv University, 6200515, Israel
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Kluxen FM, Weber K, Strupp C, Jensen SM, Hothorn LA, Garcin JC, Hofmann T. Using historical control data in bioassays for regulatory toxicology. Regul Toxicol Pharmacol 2021; 125:105024. [PMID: 34364928 DOI: 10.1016/j.yrtph.2021.105024] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/21/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022]
Abstract
Historical control data (HCD) consist of pooled control group responses from bioassays. These data must be collected and are often used or reported in regulatory toxicology studies for multiple purposes: as quality assurance for the test system, to help identify toxicological effects and their effect-size relevance and to address the statistical multiple comparison problem. The current manuscript reviews the various classical and potential new approaches for using HCD. Issues in current practice are identified and recommendations for improved use and discussion are provided. Furthermore, stakeholders are invited to discuss whether it is necessary to consider uncertainty when using HCD formally and statistically in toxicological discussions and whether binary inclusion/exclusion criteria for HCD should be revised to a tiered information contribution to assessments. Overall, the critical value of HCD in toxicological bioassays is highlighted when used in a weight-of-evidence assessment.
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Affiliation(s)
| | | | | | - Signe M Jensen
- Department of Plant and Efoldnvironmental Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Pauluhn J. Inhalation toxicity of cyclic semi-volatile methylsiloxanes: Disentangling the conundrum of phase-specific adaptations from adverse outcomes. Regul Toxicol Pharmacol 2021; 122:104923. [PMID: 33831492 DOI: 10.1016/j.yrtph.2021.104923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/23/2021] [Accepted: 03/30/2021] [Indexed: 01/06/2023]
Abstract
This paper compares the phase-specific inhalation toxicity of the cyclic semi-volatile methylsiloxanes (cVMSs) D4, D5 and D6. The objectives of this paper are to re-analyze information from acute to chronic inhalation studies on rats with these cVMSs to identify the unifying principles of phase-specific toxicity at the portal-of-entry and if they depend on acute, acute-on-chronic or chronic mechanisms. This re-analysis supports the hypothesis that concentrations must be high enough to exceed the vapor saturation at any given temperature for stabilizing the aerosol phase and evoking phase-specific effects at sites of the respiratory tract susceptible to the cVMSs-specific physicochemical properties amphiphilicity and surface tension. In summary, the portal-of-entry effects and related findings appear to be acute in nature and specific to liquid aerosol. The repeated inhalation exposure studies with D4 and D5 up to two years in duration did not reveal chronic aggravations of portal of entry outcomes. Findings at a pulmonary location where amphiphilic surfactant molecules are present appear to be caused by the acute adaptation to deposited dose. Such outcome should better be described as a high-dose liquid aerosol phenomenon imparted by the physicochemical properties "liquid" and "hydrophobic". This calls for a phase-specific human risk characterization of cVMSs.
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Affiliation(s)
- Juergen Pauluhn
- Hanover Medical School, Hannover, Germany; Bayer HealthCare, Toxicology, Wuppertal, Germany(1).
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Bomann W, Tinwell H, Jenkinson P, Kluxen FM. Metribuzin-induced non-adverse liver changes result in rodent-specific non-adverse thyroid effects via uridine 5'-diphospho-glucuronosyltransferase (UDPGT, UGT) modulation. Regul Toxicol Pharmacol 2021; 122:104884. [PMID: 33596450 DOI: 10.1016/j.yrtph.2021.104884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/19/2021] [Accepted: 02/01/2021] [Indexed: 11/18/2022]
Abstract
Metribuzin is a herbicide that inhibits photosynthesis and has been used for over 40 years. Its main target organ is the liver and to some extent the kidney in rats, dogs, and rabbits. Metribuzin shows a specific thyroxine (T4) profile in rat studies with T4 increases at low doses and T4 decreases at higher doses. Only the T4 decreases occur together with histopathological changes in the thyroid and weight changes of liver and thyroid. A set of experiments was conducted to investigate metribuzin's endocrine disruptor potential according to European guidance and regulations. The results indicate that a liver enzyme modulation, i.e. of the uridine 5'-diphospho-glucuronosyltransferase (UDPGT, UGT), is most likely responsible for both increased and decreased plasma thyroxine level and for thyroid histopathological observations. Animals with high T4 levels show low UGT activity, while animals with low T4 levels show high UGT activity. A causal relationship was inferred, since other potentially human-relevant mode of action (MOA) pathways were excluded in dedicated studies, i.e. inhibition of deiodinases (DIO), inhibition of thyroid peroxidase (TPO) or of the sodium importer system (NIS). This liver metabolism-associated MOA is considered not relevant for human hazard assessment, due to species differences in thyroid homeostasis between humans and rats and, more importantly, based on experimental data showing that metribuzin affects UGT activity in rat but not in human hepatocytes. Further, we discuss whether or not increased T4 levels in the rat, in the absence of histopathological changes, should be considered as adverse and therefore used as an appropriate hazard model for humans. Based on a weight of evidence approach, metribuzin should not be classified as an endocrine disruptor with regard to the thyroid modality.
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Affiliation(s)
- Werner Bomann
- Toxconsult, 9393 W 110th Street, 51 Corporate Woods, Suite 500, Overland Park, KS, 66210, USA.
| | - Helen Tinwell
- Bayer.SAS, 16 rue Jean-Marie Leclair, 69009, Lyon, France
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12
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Pauluhn J. Phosgene inhalation toxicity: Update on mechanisms and mechanism-based treatment strategies. Toxicology 2021; 450:152682. [PMID: 33484734 DOI: 10.1016/j.tox.2021.152682] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/28/2022]
Abstract
Phosgene (carbonyl dichloride) gas is an indispensable high-production-volume chemical intermediate used worldwide in numerous industrial processes. Published evidence of human exposures due to accidents and warfare (World War I) has been reported; however, these reports often lack specificity because of the uncharacterized exposure intensities of phosgene and/or related irritants. These may include liquid or solid congeners of phosgene, including di- and triphosgene and/or the respiratory tract irritant chlorine which are often collectively reported under the umbrella of phosgene exposure without any appreciation of their differences in causing acute lung injury (ALI). Among these irritants, phosgene gas is somewhat unique because of its poor water solubility. This prevents any appreciable retention of the gas in the upper airways and related trigeminal sensations of irritation. By contrast, in the pulmonary compartment, amphiphilic surfactant might scavenge this lipophilic gas. The interaction of phosgene and the surfactant may affect basic physiological functions controlled by Starling's and Laplace's laws, which can be followed by cardiogenic pulmonary edema. The phenotypic manifestations are dependent on the concentration × exposure duration (C × t); the higher the C × t is, the less time that is required for edema to appear. It is hypothesized that this type of edema is caused by cardiovascular and colloid osmotic imbalances to initial neurogenic events but not because of the injury itself. Thus, hemodynamic etiologies appear to cause imbalances in extravasated fluids and solute accumulation in the pulmonary interstitium, which is not drained away by the lymphatic channels of the lung. The most salient associated findings are hemoconcentration and hypoproteinemia. The involved intertwined pathophysiological processes coordinating pulmonary ventilation and cardiopulmonary perfusion under such conditions are complex. Pulmonary arterial catheter measurements on phosgene-exposed dogs provided evidence of 'cor pulmonale', a form of acute right heart failure produced by a sudden increase in resistance to blood flow in the pulmonary circulation about 20 h postexposure. The objective of this review is to critically analyze evidence from experimental inhalation studies in rats and dogs, and evidence from accidental human exposures to better understand the primary and secondary events causing cardiopulmonary dysfunction and an ensuing life-threatening lung edema. Mechanism-based diagnostic and therapeutic approaches are also considered for this form of cardiogenic edema.
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Affiliation(s)
- Juergen Pauluhn
- Covestro Deutschland AG, Global Phosgene Steering Group, 51365, Leverkusen, Germany; Hanover Medical School, Hanover, Germany; Bayer HealthCare, Wuppertal, Germany(1).
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13
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Hall AP, Tepper JS, Boyle MH, Cary MG, Flandre TG, Piaia A, Tarnow I, Macri NP, Freke MC, Nikula KJ, Paul GR, Cauvin A, Gregori M, Haworth R, Naylor S, Price M, Robinson IN, Allen A, Gelzleichter T, Hohlbaum AM, Manetz S, Wolfreys A, Colman K, Fleurance R, Jones D, Mukaratirwa S. BSTP Review of 12 Case Studies Discussing the Challenges, Pathology, Immunogenicity, and Mechanisms of Inhaled Biologics. Toxicol Pathol 2021; 49:235-260. [PMID: 33455525 DOI: 10.1177/0192623320976094] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The inhalation route is a relatively novel drug delivery route for biotherapeutics and, as a result, there is a paucity of published data and experience within the toxicology/pathology community. In recent years, findings arising in toxicology studies with inhaled biologics have provoked concern and regulatory challenges due, in part, to the lack of understanding of the expected pathology, mechanisms, and adversity induced by this mode of delivery. In this manuscript, the authors describe 12 case studies, comprising 18 toxicology studies, using a range of inhaled biotherapeutics (monoclonal antibodies, fragment antigen-binding antibodies, domain antibodies, therapeutic proteins/peptides, and an oligonucleotide) in rodents, nonhuman primates (NHPs), and the rabbit in subacute (1 week) to chronic (26 weeks) toxicology studies. Analysis of the data revealed that many of these molecules were associated with a characteristic pattern of toxicity with high levels of immunogenicity. Microscopic changes in the airways consisted of a predominantly lymphoid perivascular/peribronchiolar (PV/PB) mononuclear inflammatory cell (MIC) infiltrate, whereas changes in the terminal airways/alveoli were characterized by simple ("uncomplicated") increases in macrophages or inflammatory cell infiltrates ranging from mixed inflammatory cell infiltration to inflammation. The PV/PB MIC changes were considered most likely secondary to immunogenicity, whereas simple increases in alveolar macrophages were most likely secondary to clearance mechanisms. Alveolar inflammatory cell infiltrates and inflammation were likely induced by immune modulation or stimulation through pharmacologic effects on target biology or type III hypersensitivity (immune complex disease). Finally, a group of experts provide introductory thoughts regarding the adversity of inhaled biotherapeutics and the basis for reasonable differences of opinion that might arise between toxicologists, pathologists, and regulators.
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Affiliation(s)
| | | | | | | | - Thierry G Flandre
- 98560Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Alessandro Piaia
- 98560Novartis Institutes for Biomedical Research, Basel, Switzerland
| | | | | | - Mark C Freke
- 70294Charles River Laboratories Montreal ULC, Senneville, Quebec, Canada
| | | | | | | | | | | | - Stuart Naylor
- Charles River Laboratories, Edinburgh, United Kingdom
| | - Mark Price
- 1929GlaxoSmithKline, Ware, United Kingdom
| | | | | | | | | | | | | | - Karyn Colman
- 70089Genomics Institute for the Novartis Research Foundation, San Diego, CA, USA
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14
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Lent EM, Sussan TE, Leach GJ, Johnson MS. Using Evidence Integration Techniques in the Development of Health-Based Occupational Exposure Levels. Int J Toxicol 2020; 40:178-195. [PMID: 33297815 DOI: 10.1177/1091581820970494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Development of toxicology-based criteria such as occupational exposure levels (OELs) are rarely straightforward. This process requires a rigorous review of the literature, searching for patterns in toxicity, biological plausibility, coherence, and dose-response relationships. Despite the direct applicability, human data are rarely used primarily because of imprecise exposure estimates, unknown influence of assumptions, and confounding factors. As a result, high reliance is often placed on laboratory animal data. Often, data from a single study is typically used to represent an entire database to extrapolate an OEL, even for data-rich compounds. Here we present a holistic framework for evaluating epidemiological, controlled in vivo, mechanistic/in vitro, and computational evidence that can be useful in deriving OELs. It begins with describing a documented review process of the literature, followed by sorting of data into either controlled laboratory in vivo, in silico/read-across, mechanistic/in vitro, or epidemiological/field data categories. Studies are then evaluated and qualified based on rigor, risk of bias, and applicability for point of departure development. Other data (eg, in vitro, in silico estimates, read-across data and mechanistic information, and data that failed to meet the former criteria) are used alongside qualified epidemiological exposure estimates to help inform points of departure or human-equivalent concentrations that are based on toxic end points. Bayesian benchmark dose methods are used to estimate points of departure and for estimating uncertainty factors (UFs) to develop preliminary OELs. These are then compared with epidemiological data to support the OEL and the use and magnitude of UFs, when appropriate.
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Affiliation(s)
- Emily May Lent
- US Army Public Health Center, Toxicology Directorate, Aberdeen Proving Ground, MD, USA
| | - Thomas E Sussan
- US Army Public Health Center, Toxicology Directorate, Aberdeen Proving Ground, MD, USA
| | | | - Mark S Johnson
- US Army Public Health Center, Toxicology Directorate, Aberdeen Proving Ground, MD, USA
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15
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Lee YH, Seo DS. Toxicity of humidifier disinfectant polyhexamethylene guanidine hydrochloride by two-week whole body-inhalation exposure in rats. J Toxicol Pathol 2020; 33:265-277. [PMID: 33239844 PMCID: PMC7677626 DOI: 10.1293/tox.2020-0043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/22/2020] [Indexed: 12/02/2022] Open
Abstract
The use of polyhexamethylene guanidine hydrochloride (PHMG·HCl) as a humidifier
disinfectant caused an outbreak of pulmonary disease, leading to the deaths of pregnant
women and children in South Korea. However, limited information is available on the
inhalation toxicity of PHMG·HCl. Therefore, this study aimed to characterize the subacute
inhalation toxicity of PHMG·HCl by whole-body exposure in rats. F344 rats were exposed to
0 mg/m3, 1 mg/m3, 5 mg/m3, or 25 mg/m3 of
PHMG·HCl for 6 h/day, 5 days/week for two weeks via whole-body inhalation. Emaciation and
rale were observed in rats in the 25 mg/m3 PHMG·HCl group. Significant changes
in body weight, hematology, serum chemistry and organ weight were observed in all
PHMG·HCl-exposed groups. Gross lesions showed ballooning or red focus in the lungs of rats
in the PHMG·HCl-exposed groups. In histopathological examination, most of histological
lesions (including degeneration, atrophy, ulcer, inflammatory cell infiltration,
inflammation, and fibrosis in nasal cavity, larynx, trachea, and lungs) indicated tissue
damage by PHMG·HCl in all PHMG·HCl-exposed groups. Additionally, atrophy of the spleen,
thymus, and reproductive organs; immaturity of the testes; and cell debris in the
epididymides were affected by the reduction in body weight in PHMG·HCl-exposed groups. In
conclusion, two-week repeated whole-body inhalation exposure of rats to PHMG·HCl reveled
toxic effects on the respiratory system and secondary effects on other organs. The results
of this study indicate that the no observable adverse effect level (NOAEL) for PHMG·HCl is
below 1 mg/m3.
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Affiliation(s)
- Yong-Hoon Lee
- Inhalation Toxicity Research Center, Chemicals Research Bureau, Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, 339-30 Expo-ro, Yuseong-gu, Daejeon 305-380, Republic of Korea
| | - Dong-Seok Seo
- Inhalation Toxicity Research Center, Chemicals Research Bureau, Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, 339-30 Expo-ro, Yuseong-gu, Daejeon 305-380, Republic of Korea
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16
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Short B. Selected Aspects of Ocular Toxicity Studies With a Focus on High-Quality Pathology Reports: A Pathology/Toxicology Consultant's Perspective. Toxicol Pathol 2020; 49:673-699. [PMID: 32815474 DOI: 10.1177/0192623320946712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ocular toxicity studies are the bedrock of nonclinical ocular drug and drug-device development, and there has been an evolution in experience, technologies, and challenges to address that ensures safe clinical trials and marketing authorization. The expectations of a well-designed ocular toxicity study and the generation of a coherent, integrative ocular toxicology report and subreports are high, and this article provides a pathology/toxicology consultant's perspective on achieving that goal. The first objective is to cover selected aspects of study designs for ocular toxicity studies including considerations for contract research organization selection, minipig species selection, unilateral versus bilateral dosing, and in-life parameters based on fit-for-purpose study objectives. The main objective is a focus on a high-quality ocular pathology report that includes ocular histology procedures to meet regulatory expectations and a report narrative and tables that correlate microscopic findings with key ophthalmic findings and presents a clear interpretation of test article-, vehicle-, and procedure-related ocular and extraocular findings with identification of adversity and a pathology peer review. The last objective covers considerations for a high-quality ophthalmology report, which in concert with a high-quality pathology report, will pave the way for a best quality toxicology report for an ocular toxicity study.
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Affiliation(s)
- Brian Short
- Brian Short Consulting, LLC, Laguna Beach, CA, USA
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17
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Baldrick P, Cosenza ME, Alapatt T, Bolon B, Rhodes M, Waterson I. Toxicology Paradise: Sorting Out Adverse and Non-adverse Findings in Animal Toxicity Studies. Int J Toxicol 2020; 39:365-378. [PMID: 32618214 DOI: 10.1177/1091581820935089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A challenge for all toxicologists is defining what study findings are actually adverse versus non-adverse in animal toxicity studies, and which ones are relevant for generating a no observed adverse effect level (NOAEL) to assess human risk. This article presents views on this challenge presented by toxicologists, toxicologic pathologists, and regulatory reviewers at the 2019 annual meeting of the American College of Toxicology during a workshop entitled "Toxicology Paradise: Sorting Out Adverse and Non-adverse Findings." The speakers noted that setting a NOAEL is not always straightforward, not only for small molecules but also for biopharmaceuticals, and that a "weight of evidence" approach often is more useful than a rigid threshold-setting algorithm. Regulators from the US Food and Drug Administration and European Union told how assessment of adverse nonclinical findings is undertaken to allow clinical studies to commence and drug marketing approvals to succeed, along with the process that allows successful dialogs with regulators. Nonclinical case studies of findings judged to be adverse versus non-adverse were presented in relation to the many factors that might halt or delay clinical development. The process of defining adverse findings and the NOAEL in final study reports was discussed, as well as who should be involved in the process.
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18
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Kim YS, Lee MJ, Seo DS, Kim TH, Kim MH, Lim CH. Thirteen-week inhalation toxicity study of 1-methylnaphthalene in F344 rats. Toxicol Res 2019; 36:13-20. [PMID: 32042710 DOI: 10.1007/s43188-019-00009-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/06/2019] [Accepted: 04/01/2019] [Indexed: 10/24/2022] Open
Abstract
1-Methylnaphthalene is generally utilized in solvents, as an intermediate in organic synthesis, a dye carrier, in resins, and others. There are some toxicological studies of 1-methylnaphthalene; however, inhalation toxicity studies are rare. Each of 10 male and female F344 rats was exposed to vapors of 1-methylnaphthalene for 13 weeks (6 h a day, 5 days per week) at concentrations of 0, 0.5, 4, and 30 ppm in a whole-body inhalation chamber system. The exposure concentrations were 0.52 ± 0.05, 4.08 ± 0.25, and 30.83 ± 1.28 ppm for the low-, middle-, and high-dose group, respectively. Body weight changes were not affected by exposure to 1-methylnaphthalene. Blood prothrombin time was delayed at 30 ppm in male and female groups, and activated partial thromboplastin time was also delayed at 30 ppm in the male group. Values of alanine aminotransferase in the serum were decreased and those of albumin were increased at 30 ppm in the male group. Differential cell counts and levels of lactate dehydrogenase in the bronchoalveolar lavage fluid were not affected. However, mucous cell hyperplasia in the nasopharyngeal tissues was found and the severity was correlated to exposure concentrations. In conclusion, 1-methylnaphthalene mainly affects the upper respiratory system and the no-observed-adverse-effect level is suggested to be 4 ppm on the basis of histopathological findings.
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Affiliation(s)
- Yong-Soon Kim
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
| | - Mi-Ju Lee
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
| | - Dong-Suk Seo
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
| | - Tae-Hyun Kim
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
| | - Min-Ha Kim
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
| | - Cheol-Hong Lim
- Chemical Research Bureau, Occupational Safety and Health Research Institute, KOSHA, Daejeon, 34122 Korea
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19
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Janas MM, Zlatev I, Liu J, Jiang Y, Barros SA, Sutherland JE, Davis WP, Liu J, Brown CR, Liu X, Schlegel MK, Blair L, Zhang X, Das B, Tran C, Aluri K, Li J, Agarwal S, Indrakanti R, Charisse K, Nair J, Matsuda S, Rajeev KG, Zimmermann T, Sepp-Lorenzino L, Xu Y, Akinc A, Fitzgerald K, Vaishnaw AK, Smith PF, Manoharan M, Jadhav V, Wu JT, Maier MA. Safety evaluation of 2'-deoxy-2'-fluoro nucleotides in GalNAc-siRNA conjugates. Nucleic Acids Res 2019; 47:3306-3320. [PMID: 30820542 PMCID: PMC6468299 DOI: 10.1093/nar/gkz140] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/07/2019] [Accepted: 02/19/2019] [Indexed: 11/29/2022] Open
Abstract
For oligonucleotide therapeutics, chemical modifications of the sugar-phosphate backbone are frequently used to confer drug-like properties. Because 2′-deoxy-2′-fluoro (2′-F) nucleotides are not known to occur naturally, their safety profile was assessed when used in revusiran and ALN-TTRSC02, two short interfering RNAs (siRNAs), of the same sequence but different chemical modification pattern and metabolic stability, conjugated to an N-acetylgalactosamine (GalNAc) ligand for targeted delivery to hepatocytes. Exposure to 2′-F-monomer metabolites was low and transient in rats and humans. In vitro, 2′-F-nucleoside 5′-triphosphates were neither inhibitors nor preferred substrates for human polymerases, and no obligate or non-obligate chain termination was observed. Modest effects on cell viability and mitochondrial DNA were observed in vitro in a subset of cell types at high concentrations of 2′-F-nucleosides, typically not attained in vivo. No apparent functional impact on mitochondria and no significant accumulation of 2′-F-monomers were observed after weekly administration of two GalNAc–siRNA conjugates in rats for ∼2 years. Taken together, the results support the conclusion that 2′-F nucleotides can be safely applied for the design of metabolically stabilized therapeutic GalNAc–siRNAs with favorable potency and prolonged duration of activity allowing for low dose and infrequent dosing.
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Affiliation(s)
- Maja M Janas
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Ivan Zlatev
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Ju Liu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | | | | | - Jingxuan Liu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Xiumin Liu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Lauren Blair
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Xuemei Zhang
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Biplab Das
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Chris Tran
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Krishna Aluri
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Jing Li
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Saket Agarwal
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | | | | | | | | | | | - Yuanxin Xu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Akin Akinc
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Peter F Smith
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Vasant Jadhav
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Jing-Tao Wu
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
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20
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An expanded toxicological profile of tetramethyl bisphenol F (TMBPF), a precursor for a new food-contact metal packaging coating. Food Chem Toxicol 2019; 135:110889. [PMID: 31629790 DOI: 10.1016/j.fct.2019.110889] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 10/04/2019] [Accepted: 10/14/2019] [Indexed: 11/24/2022]
Abstract
Tetramethyl bisphenol F (TMBPF) has been shown to impart unique physical properties critical for high performance of epoxy can coatings without the estrogenic activity concerns associated with other bisphenols. To further characterize the toxicological profile of TMBPF, additional endocrine-related endpoints including in vitro aromatase inhibition and steroidogenesis assays, and in vivo androgen agonism/antagonism were performed. Systemic toxicity was also assessed by a repeat dose 90-day dietary toxicity study followed by 28-day recovery period. TMBPF did not inhibit aromatase activity, and induced estradiol and testosterone at highest non-cytotoxic concentrations (10 μM) in the steroidogenesis assay. In the Hershberger assay, TMBPF showed no androgenic activity at any dose and equivocal anti-androgenic activity at the highest dose (1000 mg/kg-bw/d). In a 90-day dietary toxicity study with 28-day recovery period, observations including changes in clinical pathology, absolute and relative organ weights, and microscopic findings are discussed. In this current study, the no observed adverse effect level was considered to be 750 mg/kg-bw/d for female rats and 1000 mg/kg-bw/d for male rats with no biologically significant changes to endocrine endpoints at any dose level. Our findings provide further evidence that TMBPF is a low-toxicity substance with a toxicology profile distinct from some other bisphenols.
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21
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Gopinath C, Mowat V. Toxicologic Pathology Forum*: Opinion on Designation of Adverse and Nonadverse Histopathological Findings in Toxicity Studies: The Pathologist’s Dilemma. Toxicol Pathol 2019; 47:564-573. [DOI: 10.1177/0192623319854040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In this opinion piece, we discuss some proposed principles for designating adversity and nonadversity of histopathological changes. The suggested approach categorizes the classes of findings noted in toxicity studies with illustrations and examples and suggests adversity or nonadversity for each class, in the authors’ opinions, with rationales. Although the suggestions and examples offered in this opinion piece are generally in agreement with Society of Toxicologic Pathology best practices guideline on adversity, the authors suggest and highlight occasional divergences and differences of opinion. This is because making an adversity call is a complex and challenging topic that is difficult to simplify. Some of the challenges in deciding on adversity are discussed, especially those related to making an adversity call on a histopathological finding in isolation, based on the nature and extent of severity. The authors demonstrate some of these situations with examples. Finally, the authors suggest, in contrast to the guidelines, occasional use of a separate category for findings that are less easily classified. [Box: see text]
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22
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Goumenou M, Tsatsakis A. Proposing new approaches for the risk characterisation of single chemicals and chemical mixtures: The source related Hazard Quotient (HQ S) and Hazard Index (HI S) and the adversity specific Hazard Index (HI A). Toxicol Rep 2019; 6:632-636. [PMID: 31334033 PMCID: PMC6616343 DOI: 10.1016/j.toxrep.2019.06.010] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Indexed: 11/26/2022] Open
Abstract
A hazard quotient (HQ) for a single chemical and the hazard index (HI) for a mixture of chemicals were first described as approaches for risk characterisation by the EPA. HQ is defined as the ratio of exposure to an appropriate reference dose such as the ADI. HI is the sum of the HQs of the chemicals in a mixture. HQ and HI have been used to characterise risk after various exposure scenarios. However, both approaches have a significant limitation in the way they are used. The accurate use of HQ or HI requires estimation of aggregate exposure, that is, exposure to a given chemical(s) from all possible relevant sources. In many studies, risk is assessed assuming exposure from a specific source such as, consumption of water or a specific food item, in which chemical(s) concentration(s) have been measured. In this case the classic HQ/HI approach can result in significant underestimation of risk. For this purpose, we developed an alternative approach, named as Source Related HQ (HQs) where HQS is the ratio of the exposure from the specific source of interest to the respected reference values. According to our approach the HQS, before being compared to the reference dose, should be adjusted by a correction factor, in order to simulate aggregated exposure. A correction factor can be calculated based on the permitted exposure contribution from the specific source to the permitted aggregated exposure. Another important limitation specific to the HI approach is the use of chemical specific ADIs that do not correspond to the same critical effect. In this study, we present an analysis based on the individual critical effects, in order to derive the critical effect and an adversity specific Hazard Index (HIA) and risk characterisation for the whole mixture.
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Affiliation(s)
- Marina Goumenou
- Centre of Toxicology Science and Research, University of Crete, School of Medicine, Crete, Greece
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23
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Levorato S, Rietjens IMCM, Carmichael PL, Hepburn PA. Novel approaches to derive points of departure for food chemical risk assessment. Curr Opin Food Sci 2019. [DOI: 10.1016/j.cofs.2019.02.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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24
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Paulsen TR, Stiller S, Weber K, Donath C, Schreiband G, Jensen KH. A 90-day toxicity and genotoxicity study with high-purity phenylcapsaicin. TOXICOLOGY RESEARCH AND APPLICATION 2018. [DOI: 10.1177/2397847318773060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To evaluate the safety of the synthetic capsaicin analogue phenylcapsaicin (PheCap; 7-phenylhept-6-yne-acid-hydroxy-3-mathoxylbenzylamide, CAS no 848127-67-3), a 90-day repeated dose oral gavage of 0, 30, 100 or 250 mg/kg body weight (bw)/day toxicity study with a 28-day recovery period was conducted using Wistar rats. Examinations of clinical signs, body and organ weight, haematology, urinalysis, clinical chemistry, food consumption and macroscopic, as well as histopathological tissue examinations were carried out for signs of toxicity. Degenerative, but reversible changes in the liver at 250 mg/kg bw/day, and local irritating effects in the stomach at 100 and 250 mg/kg bw/day were found. These findings were associated with test item-related clinical symptoms, that is, diarrhoea, salivation and moving of bedding material. PheCap did neither cause gene mutations by base pair changes or frame shifts in the genome of the tester stains Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537 or TA 102 nor induce structural and/or numerical chromosomal damage in human lymphocytes. Therefore, it can be concluded that PheCap is not genotoxic. The No Observed Adverse Effect Level (NOAEL) of PheCap for systemic toxicity is considered to be at 100 mg/kg bw/day which is based on degenerative changes in the liver. Due to irritating effects in the stomach, the NOAEL for local effects was established at 30 mg/kg bw/day.
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Affiliation(s)
| | | | | | - Claudia Donath
- Eurofins BioPharma Product Testing Munich GmbH, Planegg, Germany
| | | | - Knut Helge Jensen
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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