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Keyser BM, Leverette R, Wertman J, Shutsky T, McRae R, Szeliga K, Makena P, Jordan K. Evaluation of Cytotoxicity and Oxidative Stress of Whole Aerosol from Vuse Alto ENDS Products. TOXICS 2024; 12:129. [PMID: 38393224 PMCID: PMC10892160 DOI: 10.3390/toxics12020129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024]
Abstract
Assessment of in vitro cytotoxicity is an important component of tobacco product toxicological evaluations. However, current methods of regulatory testing involve exposing monolayer cell cultures to various preparations of aerosols from cigarettes or other emerging products such as electronic nicotine delivery systems (ENDS), which are not representative of human exposure. In the present study, a whole aerosol (WA) system was used to expose lung epithelial cultures (2D and 3D) to determine the potential of six Vuse Alto ENDS products that varied in nicotine content (1.8%, 2.4%, and 5%) and flavors (Golden Tobacco, Rich Tobacco, Menthol, and Mixed Berry), along with a marketed ENDS and a marked cigarette comparator to induce cytotoxicity and oxidative stress. The WA from the Vuse Alto ENDS products was not cytotoxic in the NRU and MTT assays, nor did it activate the Nrf2 reporter gene, a marker of oxidative stress. In summary, Vuse Alto ENDS products did not induce cytotoxic or oxidative stress responses in the in vitro models. The WA exposures used in the 3D in vitro models described herein may be better suited than 2D models for the determination of cytotoxicity and other in vitro functional endpoints and represent alternative models for regulatory evaluation of tobacco products.
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Affiliation(s)
- Brian M. Keyser
- RAI Services Company, Winston-Salem, NC 27106, USA; (R.L.); (J.W.); (K.S.); (P.M.); (K.J.)
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2
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Miller-Holt J, Behrsing H, Crooks I, Curren R, Demir K, Gafner J, Gillman G, Hollings M, Leverette R, Oldham M, Simms L, Stankowski LF, Thorne D, Wieczorek R, Moore MM. Key challenges for in vitro testing of tobacco products for regulatory applications: Recommendations for dosimetry. Drug Test Anal 2023; 15:1175-1188. [PMID: 35830202 PMCID: PMC9897201 DOI: 10.1002/dta.3344] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/02/2022] [Accepted: 07/05/2022] [Indexed: 02/05/2023]
Abstract
The Institute for In Vitro Sciences (IIVS) is sponsoring a series of workshops to develop recommendations for optimal scientific and technical approaches for conducting in vitro assays to assess potential toxicity within and across tobacco and various next-generation products (NGPs) including heated tobacco products (HTPs) and electronic nicotine delivery systems (ENDSs). This publication was developed by a working group of the workshop members in conjunction with the sixth workshop in that series entitled "Dosimetry for conducting in vitro evaluations" and focuses on aerosol dosimetry for aerosol exposure to combustible cigarettes, HTP, and ENDS aerosolized tobacco products and summarizes the key challenges as well as documenting areas for future research.
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Affiliation(s)
| | - Holger Behrsing
- Institute for In Vitro Sciences, Gaithersburg, Maryland, USA
| | - Ian Crooks
- Consumer Product Safety, British American Tobacco, Southampton, UK
| | - Rodger Curren
- Institute for In Vitro Sciences, Gaithersburg, Maryland, USA
| | - Kubilay Demir
- Regulatory Science, JUUL Labs Inc., 1000 F Street NW, Washington D.C. 20004, USA
| | - Jeremie Gafner
- Scientific & Regulatory Affairs, JT International SA, Geneva, Switzerland
| | - Gene Gillman
- Regulatory Science, JUUL Labs Inc., 1000 F Street NW, Washington D.C. 20004, USA
| | - Michael Hollings
- Genetic Toxicology, Labcorp Early Development Laboratories Ltd., Harrogate, UK
| | - Robert Leverette
- Scientific & Regulatory Affairs, RAI Services Company, Winston-Salem, North Carolina, USA
| | - Michael Oldham
- Regulatory Science, JUUL Labs Inc., 1000 F Street NW, Washington D.C. 20004, USA
| | - Liam Simms
- Group Science and Regulatory Affairs, Imperial Brands, Bristol, UK
| | - Leon F. Stankowski
- Genetic and In Vitro Toxicology, Charles River Laboratories–Skokie, Skokie, Illinois, USA
| | - David Thorne
- Consumer Product Safety, British American Tobacco, Southampton, UK
| | - Roman Wieczorek
- Group Science and Regulatory Affairs, Reemtsma Cigarettenfabriken GmbH, an Imperial Brands PLC Company, Hamburg, Germany
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3
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Wieczorek R, Trelles Sticken E, Pour SJ, Chapman F, Röwer K, Otte S, Stevenson M, Simms L. Characterisation of a smoke/ aerosol exposure in vitro system (SAEIVS) for delivery of complex mixtures directly to cells at the air-liquid interface. J Appl Toxicol 2023. [PMID: 36734622 DOI: 10.1002/jat.4442] [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: 10/24/2022] [Revised: 01/23/2023] [Accepted: 01/31/2023] [Indexed: 02/04/2023]
Abstract
In vitro testing is important to characterise biological effects of consumer products, including nicotine delivery products such as cigarettes, e-cigarettes and heated tobacco products. Users' cells are exposed to these products' aerosols, of variant chemical compositions, as they move along the respiratory tract. In vitro exposure systems are available to model such exposures, including delivery of whole aerosols to cells, and at the air-liquid interface. Whilst there are clear advantages of such systems, factors including time to aerosol delivery, aerosol losses and number of cell cultures that can be exposed at one time could be improved. This study aimed to characterise a custom-built smoke/ aerosol exposure in vitro system (SAEIVS) using 1R6F reference cigarette smoke. This system contains five parallel smoking chambers and delivers different dilutions of smoke/ aerosol to two separate cell culture exposure chambers in <10 s. Using two dosimetry measures (optical density 400 nm [OD400 ]; mass spectrometric nicotine quantification), the SAEIVS demonstrated excellent linearity of smoke dilution prior to exposure (R2 = 0.9951 for mass spectrometric quantification; R2 = 0.9965 for OD400 ) and consistent puff-wise exposures across 24 and 96 well plates in cell culture relevant formats (e.g., within inserts). Smoke loss was lower than previously reported for other systems (OD400 : 16%; nicotine measurement: 20%). There was good correlation of OD400 and nicotine measurements, indicating that OD was a useful surrogate for exposure dosimetry for the product tested. The findings demonstrated that the SAEIVS is a fit-for-purpose exposure system for the reproducible dose-wise exposure assessment of nicotine delivery product aerosols.
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Affiliation(s)
| | | | | | - Fiona Chapman
- Imperial Brands PLC, 121 Winterstoke Road, BS3 2LL, Bristol, UK
| | - Karin Röwer
- Reemtsma Cigarettenfabriken GmbH, Hamburg, Germany
| | - Sandra Otte
- Reemtsma Cigarettenfabriken GmbH, Hamburg, Germany
| | | | - Liam Simms
- Imperial Brands PLC, 121 Winterstoke Road, BS3 2LL, Bristol, UK
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Keyser BM, Leverette R, Hollings M, Seymour A, Weidman RA, Bequette CJ, Jordan K. Characterization of smoke and aerosol deliveries from combustible cigarettes, heated tobacco products and electronic nicotine delivery systems in the Vitrocell® Mammalian 6/48 exposure module. Toxicol Rep 2022; 9:1985-1992. [DOI: 10.1016/j.toxrep.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 10/27/2022] [Accepted: 11/03/2022] [Indexed: 11/06/2022] Open
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Crooks I, Hollings M, Leverette R, Jordan K, Breheny D, Moore MM, Thorne D. A comparison of cigarette smoke test matrices and their responsiveness in the mouse lymphoma assay: A case study. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2022; 879-880:503502. [PMID: 35914858 DOI: 10.1016/j.mrgentox.2022.503502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/22/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
No cigarette smoke test matrix is without limitation, due to the complexity of the starting aerosol and phase to phase dynamics. It is impossible to capture all chemicals at the same level of efficiency, therefore, any test matrix will inadvertently or by design fractionate the test aerosol. This case study examines how four different test matrices derived from cigarette smoke can be directly compared. The test matrices assessed were as follows, total particulate matter (TPM), gas vapour phase (GVP), a combination of TPM + GVP and whole aerosol (WA). Here we use an example assay, the mouse lymphoma assay (MLA) to demonstrate that data generated across four cigarette smoke test matrices can be compared. The results show that all test matrices were able to induce positive mutational events, but with clear differences in the biological activity (both potency and toxicity) between them. TPM was deemed the most potent test article and by extension, the particulate phase is interpreted as the main driver of genotoxic induced responses in the MLA. However, the results highlight that the vapour phase is also active. MLA appeared responsive to WA, with potentially lower potency, compared to TPM approaches. However, this observation is caveated in that the WA approaches used for comparison were made on a newly developed experimental method using dose calculations. The TPM + GVP matrix had comparable activity to TPM alone, but interestingly induced a greater number of mutational events at comparable relative total growth (RTG) and TPM-equivalent doses when compared to other test matrices. In conclusion, this case study highlights the importance of understanding test matrices in response to the biological assay being assessed and we note that not all test matrices are equal.
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Affiliation(s)
- Ian Crooks
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - Michael Hollings
- Labcorp Early Development Laboratories Ltd., Harrogate, North Yorkshire HG3 1PY, UK
| | - Robert Leverette
- Reynolds American Inc, 950 Reynolds Blvd., Winston-Salem, NC 27105, USA
| | - Kristen Jordan
- Reynolds American Inc, 950 Reynolds Blvd., Winston-Salem, NC 27105, USA
| | - Damien Breheny
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | | | - David Thorne
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK.
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Primavessy D, Metz J, Schnur S, Schneider M, Lehr CM, Hittinger M. Pulmonary in vitro instruments for the replacement of animal experiments. Eur J Pharm Biopharm 2021; 168:62-75. [PMID: 34438019 DOI: 10.1016/j.ejpb.2021.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/19/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022]
Abstract
Advanced in vitro systems often combine a mechanical-physical instrument with a biological component e.g. cell culture models. For testing of aerosols, it is of advantage to consider aerosol behavior, particle deposition and lung region specific cell lines. Although there are many good reviews on the selection of cell cultures, articles on instruments are rare. This article focuses on the development of in vitro instruments targeting the exposure of aerosols on cell cultures. In this context, guidelines for toxicity investigation are taken into account as the aim of new methods must be the prediction of human relevant data and the replacement of existing animal experiments. We provide an overview on development history of research-based instruments from a pharmaceutical point of view. The standardized commercial devices resulting from the research-based instruments are presented and the future perspectives on pulmonary in vitro devices are discussed.
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Affiliation(s)
- Daniel Primavessy
- Department of Drug Delivery, PharmBioTec Research and Development GmbH, Saarbrücken, Germany.
| | - Julia Metz
- Department of Drug Delivery, PharmBioTec Research and Development GmbH, Saarbrücken, Germany
| | - Sabrina Schnur
- Department of Drug Delivery, PharmBioTec Research and Development GmbH, Saarbrücken, Germany; Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
| | - Marc Schneider
- Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery, PharmBioTec Research and Development GmbH, Saarbrücken, Germany; Department of Pharmacy, Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany; Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Saarbrücken, Germany
| | - Marius Hittinger
- Department of Drug Delivery, PharmBioTec Research and Development GmbH, Saarbrücken, Germany; 3RProducts Marius Hittinger, Blieskastel, Germany
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7
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Thorne D, Wieczorek R, Fukushima T, Shin HJ, Leverette R, Ballantyne M, Li X, Bombick B, Yoshino K. A survey of aerosol exposure systems relative to the analysis of cytotoxicity: A Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) perspective. TOXICOLOGY RESEARCH AND APPLICATION 2021. [DOI: 10.1177/23978473211022267] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
During a Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) meeting, the in vitro toxicity testing Sub-Group (IVT SG) met to discuss the evolving field of aerosol exposure research. Given the diversity of exposure parameters and biological endpoints being used, it was considered a high priority to investigate and contextualise the responses obtained. This is particularly driven by the inability to compare between studies on different exposure systems due to user preferences and protocol differences. Twelve global tobacco and contract research companies met to discuss this topic and formulate an aligned approach on how this diverging field of research could be appropriately compared. Something that is becoming increasingly important, especially in the light of more focused regulatory scrutiny. A detailed and comprehensive survey was conducted on over 40 parameters ranging from aerosol generation, dilution and data analysis across eight geographically independent laboratories. The survey results emphasise the diversity of in vitro exposure parameters and methodologies employed across the IVT SG and highlighted pockets of harmonisation. For example, many of the biological protocol parameters are consistent across the Sub-Group. However, variables such as cell type and exposure time remain largely inconsistent. The next steps for this work will be to map parameters and system data against biological findings and investigate whether the observed inconsistencies translate into increased biological variability. The results from the survey provide improved awareness of parameters and nuances, that may be of substantial benefit to scientists in intersecting fields and in the development of harmonised approaches.
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Affiliation(s)
- David Thorne
- British American Tobacco, Group R&D, Southampton, Hampshire, UK
| | | | - Toshiro Fukushima
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Kanagawa, Japan
| | - Han-Jae Shin
- Korean Tobacco & Ginseng Corporation, Yuseong-gu, Daejeon, Republic of Korea
| | | | | | - Xiang Li
- Zhengzhou Tobacco Research Institute of China National Tobacco Corporation, Zhengzhou, People’s Republic of China
| | | | - Kei Yoshino
- Scientific Product Assessment Center, R&D Group, Japan Tobacco Inc., Yokohama, Kanagawa, Japan
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8
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Phillips G, Czekala L, Behrsing HP, Amin K, Budde J, Stevenson M, Wieczorek R, Walele T, Simms L. Acute electronic vapour product whole aerosol exposure of 3D human bronchial tissue results in minimal cellular and transcriptomic responses when compared to cigarette smoke. TOXICOLOGY RESEARCH AND APPLICATION 2021. [DOI: 10.1177/2397847320988496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The use of electronic vapour products (EVPs) continues to increase worldwide and with advances in cell culture systems, molecular biology and the computational sciences there is also accumulating evidence of their potential reduced toxicity and reduced potential harm when compared to cigarette smoke. To further understand the potential risks and health effects associated with exposure to EVP aerosols we have assessed the cellular and transcriptomic response from a commercially available lung tissue culture system (MucilAirTM) following a single sub-cytotoxic exposure to cigarette smoke and the equivalent nicotine delivered dose of EVP aerosol. The transcriptomic, cellular (cilia beat frequency (CBF) and percent active area (%AA), trans epithelial electrical resistance (TEER), histology) and cytokine release were assessed at 4- and 48- hours following recovery from air, EVP aerosol (8.4% V/V: mybluTM blueberry flavour, 2.4% nicotine) and 3R4F smoke (3.5% V/V: exposure). No pathological changes were observed at either recovery time point from any exposure. Air and EVP aerosol exposure had no effect on CBF, %AA nor TEER at 48 hours. Exposure to cigarette smoke resulted in a decrease in TEER, an increase in CBF and the release of proinflammatory cytokines at both recovery time points. Although the number of significantly expressed genes was minimal following exposure to EVP aerosol, exposure to 3R4F smoke resulted in a significant upregulation of several disease relevant pathways. These data provide evidence that following an acute exposure to EVP aerosol there is significantly less damage to lung cells in culture than the equivalent, nicotine based, dose of cigarette smoke.
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Affiliation(s)
- Gary Phillips
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, United Kingdom
| | - Lukasz Czekala
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, United Kingdom
| | - Holger P Behrsing
- Respiratory Toxicology, Institute for In Vitro Sciences, Inc., Gaithersburg, MD, USA
| | - Khalid Amin
- University of Minnesota Medical Center, Minneapolis, MN, USA
| | - Jessica Budde
- Reemtsma Cigarettenfabriken GmbH, An Imperial Brands PLC Company, Hamburg, Germany
| | - Matthew Stevenson
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, United Kingdom
| | - Roman Wieczorek
- Reemtsma Cigarettenfabriken GmbH, An Imperial Brands PLC Company, Hamburg, Germany
| | - Tanvir Walele
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, United Kingdom
| | - Liam Simms
- Group Science and Regulatory Affairs, Imperial Brands PLC, Bristol, United Kingdom
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9
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Cao X, Coyle JP, Xiong R, Wang Y, Heflich RH, Ren B, Gwinn WM, Hayden P, Rojanasakul L. Invited review: human air-liquid-interface organotypic airway tissue models derived from primary tracheobronchial epithelial cells-overview and perspectives. In Vitro Cell Dev Biol Anim 2020; 57:104-132. [PMID: 33175307 PMCID: PMC7657088 DOI: 10.1007/s11626-020-00517-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
The lung is an organ that is directly exposed to the external environment. Given the large surface area and extensive ventilation of the lung, it is prone to exposure to airborne substances, such as pathogens, allergens, chemicals, and particulate matter. Highly elaborate and effective mechanisms have evolved to protect and maintain homeostasis in the lung. Despite these sophisticated defense mechanisms, the respiratory system remains highly susceptible to environmental challenges. Because of the impact of respiratory exposure on human health and disease, there has been considerable interest in developing reliable and predictive in vitro model systems for respiratory toxicology and basic research. Human air-liquid-interface (ALI) organotypic airway tissue models derived from primary tracheobronchial epithelial cells have in vivo–like structure and functions when they are fully differentiated. The presence of the air-facing surface allows conducting in vitro exposures that mimic human respiratory exposures. Exposures can be conducted using particulates, aerosols, gases, vapors generated from volatile and semi-volatile substances, and respiratory pathogens. Toxicity data have been generated using nanomaterials, cigarette smoke, e-cigarette vapors, environmental airborne chemicals, drugs given by inhalation, and respiratory viruses and bacteria. Although toxicity evaluations using human airway ALI models require further standardization and validation, this approach shows promise in supplementing or replacing in vivo animal models for conducting research on respiratory toxicants and pathogens.
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Affiliation(s)
- Xuefei Cao
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., AR, Jefferson, USA.
| | - Jayme P Coyle
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
| | - Rui Xiong
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., AR, Jefferson, USA
| | - Yiying Wang
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., AR, Jefferson, USA
| | - Robert H Heflich
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., AR, Jefferson, USA
| | - Baiping Ren
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., AR, Jefferson, USA
| | - William M Gwinn
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Durham, NC, USA
| | | | - Liying Rojanasakul
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV, USA
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10
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Wavreil FD, Heggland SJ. Cinnamon-flavored electronic cigarette liquids and aerosols induce oxidative stress in human osteoblast-like MG-63 cells. Toxicol Rep 2019; 7:23-29. [PMID: 31871899 PMCID: PMC6909334 DOI: 10.1016/j.toxrep.2019.11.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/26/2022] Open
Abstract
As noncombustible nicotine delivery devices, electronic cigarettes (e-cigarettes) are the most popular tobacco product among youth. The widespread popularity of e-cigarettes combined with possible health consequences suggest a need to further research health hazards associated with e-cigarette use. Since conventional tobacco use is a risk factor for osteoporosis, this study investigates the impact of nicotine-free, cinnamon-flavored e-cigarette liquid (e-liquid) on bone-forming osteoblasts compared to flavorless e-liquid. Human tumor-derived osteoblast-like MG-63 cells were exposed for 24 h or 48 h to 0.0.4 %, 0.04 %, 0.4 % or 1 % of unvaped e-liquid or 0.0025 %, 0.025 %, 0.25 %, 1 % or 2.5 % of aerosol condensate in addition to a culture medium only control. Changes in cell viability were assessed by MTT assay, and the expression of a key bone protein, collagen type I, was analyzed by immunofluorescence. Production of reactive oxygen species (ROS) was detected by fluorometry to assess oxidative stress. Cell viability decreased in a dose-dependent manner, and ROS production increased, which was most pronounced with cinnamon-flavored e-liquids. There were no detectable changes in collagen type I protein following exposure to any of the aerosol condensates. This study demonstrates osteoblast-like cells are sensitive to both e-liquids and aerosol condensates and suggests the cytotoxicity of cinnamon-flavored e-liquids might be associated with oxidative stress rather than changes in collagen type I protein expression. This in vitro study provides insight into the potential impacts of e-cigarette use on bone cells.
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Affiliation(s)
| | - Sara J. Heggland
- Department of Biology, The College of Idaho, 2112 Cleveland Blvd, Caldwell, ID, 83605, USA
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Marescotti D, Mathis C, Belcastro V, Leroy P, Acali S, Martin F, Dulize R, Bornand D, Peric D, Guedj E, Ortega Torres L, Biasioli M, Fuhrimann M, Fernandes E, Frauendorfer F, Gonzalez Suarez I, Sciuscio D, Ivanov NV, Peitsch MC, Hoeng J. Systems toxicology assessment of a representative e-liquid formulation using human primary bronchial epithelial cells. Toxicol Rep 2019; 7:67-80. [PMID: 31886136 PMCID: PMC6921209 DOI: 10.1016/j.toxrep.2019.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/18/2019] [Accepted: 11/24/2019] [Indexed: 12/20/2022] Open
Abstract
The development of reduced-risk products aims to provide alternatives to cigarettes that present less risk of harm for adult smokers. Responsible use of flavoring substances in these products may fulfill an important role in product acceptance. While most flavoring substances used in such products are also used by the food industry and are considered safe when ingested, their impact when inhaled may require further assessment. To aid in such an assessment, a three-step approach combining real-time cellular analysis, phenotypic high-content screening assays, and gene expression analysis was developed and tested in normal human bronchial epithelial cells with 28 flavoring substances commonly used in e-liquid formulations, dissolved individually or as a mixture in a base solution composed of propylene glycol, vegetable glycerin, and 0.6% nicotine. By employing this approach, we identified individual flavoring substances that potentially contribute greatly to the overall mixture effect (citronellol and alpha-pinene). By assessing modified mixtures, we showed that, although cytotoxic effects were found when assessed individually, alpha-pinene did not contribute to the overall mixture cytotoxicity. Most of the cytotoxic effect appeared to be attributable to citronellol, with the remaining substances contributing due to synergistic effects. We developed and used different scoring methods (Tox-Score, Phenotypic Score, and Biological Impact Factor/Network Perturbation Amplitude), ultimately enabling a ranking based on cytotoxicity, phenotypic outcome, and molecular network perturbations. This case study highlights the benefits of testing both individual flavoring substances and mixtures for e-liquid flavor assessment and emphasized the importance of data sharing for the benefit of consumer safety.
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Affiliation(s)
- Diego Marescotti
- Corresponding author at: PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000 Neuchâtel, Switzerland.
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