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Bishop E, Miazzi F, Bozhilova S, East N, Evans R, Smart D, Gaca M, Breheny D, Thorne D. An in vitro toxicological assessment of two electronic cigarettes: E-liquid to aerosolisation. Curr Res Toxicol 2024; 6:100150. [PMID: 38298371 PMCID: PMC10827682 DOI: 10.1016/j.crtox.2024.100150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 01/04/2024] [Accepted: 01/10/2024] [Indexed: 02/02/2024] Open
Abstract
Interest in the toxicological assessment of iterations of e-cigarette devices, e-liquid formulations and flavour use is increasing. Here, we describe a multiple test matrix and in vitro approach to assess the biological impact of differing e-cigarette activation mechanism (button vs. puff-activated) and heating technology (cotton vs. ceramic wick). The e-liquids selected for each device contained the same nicotine concentration and flavourings. We tested both e-liquid and aqueous extract of e-liquid aerosol using a high throughput cytotoxicity and genotoxicity screen. We also conducted whole aerosol assessment both in a reconstituted human airway lung tissue (MucilAir) with associated endpoint assessment (cytotoxicity, TEER, cilia beat frequency and active area) and an Ames whole aerosol assay with up to 900 consecutive undiluted puffs. Following this testing it is shown that the biological impact of these devices is similar, taking into consideration the limitations and capturing efficiencies of the different testing matrices. We have contextualised these responses against previous published reference cigarette data to establish the comparative reduction in response consistent with reduced risk potential of the e-cigarette products tested in this study as compared to conventional cigarettes.
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Affiliation(s)
- E. Bishop
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - F. Miazzi
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - S. Bozhilova
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - N. East
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - R. Evans
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Smart
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - M. Gaca
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Breheny
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D. Thorne
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
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Bishop E, East N, Miazzi F, Fiebelkorn S, Breheny D, Gaca M, Thorne D. A contextualised e-cigarette testing strategy shows flavourings do not impact lung toxicity in vitro. Toxicol Lett 2023; 380:1-11. [PMID: 36935081 DOI: 10.1016/j.toxlet.2023.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 02/27/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023]
Abstract
Vaping has the potential to reduce the individual health risks associated with smoking and e-cigarette flavours have been reported to help smokers' transition from cigarettes. In this manuscript, we provide evidence to support the reduced risk potential of e-cigarette aerosols and flavours by assessing commercially available e-liquids (Vuse ePod - Manufactured by British American Tobacco) in a 2D in vitro screening approach. We also analysed selected flavours using a more physiologically relevant 3D (MucilAir) whole aerosol exposure model, measuring toxicity and functional endpoints such as Trans Epithelial Electrical Resistance, Cilia Beat Frequency and Active Area. To contextualise responses, we have compared e-cigarette aerosol to cigarette smoke (1R6F research cigarette) and calculated the percentage reduction using a point of departure approach. We show that aerosolised flavoured e-liquids, (appropriately stewarded) do not increase the overall measured aerosol toxicity when compared to cigarette smoke. In fact, we demonstrate that the measured in vitro cellular toxicity of flavoured e-cigarette products remains >95% reduced when compared to cigarette smoke toxicity, using point of departure (IC80) approach. These data indicate that the overall product toxicity is not increased in a flavour dependent manner and that flavoured e-cigarette products can potentially play a role in tobacco harm reduction.
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Affiliation(s)
- E Bishop
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - N East
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - F Miazzi
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - S Fiebelkorn
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D Breheny
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - M Gaca
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - D Thorne
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
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Bishop E, Terry A, East N, Breheny D, Gaca M, Thorne D. A 3D in vitro comparison of two undiluted e-cigarette aerosol generating systems. Toxicol Lett 2022; 358:69-79. [PMID: 35032609 DOI: 10.1016/j.toxlet.2022.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 11/19/2021] [Accepted: 01/11/2022] [Indexed: 10/19/2022]
Abstract
In vitro studies play an important role in supporting the toxicological assessment of e-cigarettes, with many current methods reliant on sophisticated in vitro exposure systems designed for conventional cigarette testing. In this study, we have compared two distinct systems; the modified Vitrocell VC10 and Borgwaldt LM4E designed to deliver undiluted e-cigarette aerosol. We assessed the cytotoxicity response of 3D reconstituted lung tissue (MucilAir) exposed to undiluted aerosol from ePen3 (closed modular e-cigarette) using these two exposure systems. As the induced cytotoxicity profiles were comparable, we then compared these responses against historical eBox (open modular e-cigarette) and 3R4F reference cigarette data to show evolution of product technology. This latter approach was deemed possible by monitoring intrinsic donor-to-donor control variability over a three-year period, bridging between exposure systems and observed biological responses. Despite the differences in the technology, on a puff-by-puff basis these machines gave remarkably similar cytotoxicity profiles for ePen3, as determined by MTT, and consistency of pre-cytotoxicity markers: transepithelial electrical resistance (TEER), cilia beat frequency and cilia active area. When responses are compared as a function of exposed nicotine concentration, we see differences due to the dynamics of the exposure systems. The parity of responses between the systems in generated undiluted aerosol has allowed us to compare back to previously published eBox data, irrespective of aerosol generating system and MucilAir donor, showing how evolution from open systems to podmod e-cigarette design can make a step change in the cytotoxicity profile of the product.
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Affiliation(s)
- E Bishop
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK.
| | - A Terry
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - N East
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - D Breheny
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - M Gaca
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - D Thorne
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
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East N, Bishop E, Breheny D, Gaca M, Thorne D. A screening approach for the evaluation of tobacco-free 'modern oral' nicotine products using Real Time Cell Analysis. Toxicol Rep 2021; 8:481-488. [PMID: 33718000 PMCID: PMC7933807 DOI: 10.1016/j.toxrep.2021.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/28/2021] [Accepted: 02/21/2021] [Indexed: 12/23/2022] Open
Abstract
In many regulated industries there is an increasing pressure to provide timely and robust risk assessment data to support product launches. Real-time cell analysis (RTCA) is a tool that allows for the fast and relatively labour-free cytotoxic assessment of test compounds, compared to traditional methods. Here, we propose an application for the RTCA platform to provide a screening approach, to evaluate the cytotoxic potential of tobacco-free nicotine pouches, also termed modern oral product (MOP), to determine the contribution of differing nicotine strengths (4-11 mg) and a range of available flavour types from multiple markets, on overall product toxicity. Aqueous extracts were prepared for all products using 1 pouch in 20 mL cell culture media and applied to the cell system for 24 h. Test extract nicotine concentrations reflected the increases in product nicotine strength; however, these changes were not present in the same magnitude in the cytotoxicity data obtained from both primary human gingival fibroblasts (HGF) and an NCI-H292 human bronchial epithelial continuous cell line. Furthermore, across the range of flavours and product nicotine strengths tested, H292 cells whilst not the target organ for oral product use, accurately predicted the results seen in HGFs and could be considered a useful surrogate for fast screening studies. H292 cells are more easily cultured and for longer periods, offering a more compatible test system. In conclusion, the data demonstrate the utility of the RTCA platform for the quick assessment of a large range of product variants. Furthermore, for a cytotoxicity measure with this test product, the simple H292 cell line can predict outcomes in the more complex HGF and provide useful pre-clinical cytotoxicity screening data to inform the risk assessment of MOPs and the relative contribution of flavourings, nicotine and other components.
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Key Words
- AqE, Aqueous extract
- CRP, 1.1 CORESTA Reference Product 1.1
- Cytotoxicity
- H292, Human bronchial epithelial cells
- HGF, Human gingival fibroblasts
- In vitro
- LDH, Lactate dehydrogenase assay
- MOP, Modern oral product
- MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide
- NRU, Neutral red uptake assay
- Nicotine
- RTCA
- RTCA, Real Time Cell Analysis
- Risk assessment
- Tobacco-free modern oral tobacco
- Tobacco-free nicotine pouches
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Affiliation(s)
- N. East
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - E. Bishop
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - D. Breheny
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - M. Gaca
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
| | - D. Thorne
- British American Tobacco, R&D, Southampton, Hampshire, SO15 8TL, UK
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Breheny D, Thorne D, Baxter A, Bozhilova S, Jaunky T, Santopietro S, Taylor M, Terry A, Gaça M. The in vitro assessment of a novel vaping technology. Toxicol Rep 2020; 7:1145-1156. [PMID: 32983902 PMCID: PMC7494588 DOI: 10.1016/j.toxrep.2020.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/26/2020] [Accepted: 08/18/2020] [Indexed: 11/17/2022] Open
Abstract
We have developed a novel vaping product (NVP) IS1.0(TT), which utilises a stainless-steel mesh to transfer and vaporise the e-liquid, mitigating some of the potential sources of toxicants that can be generated using the more traditional 'wick and coil' approach. The emissions from IS1.0(TT) have previously been found to have lower levels of toxicants overall when directly compared with a commercial wick and coil e-cig. This current study assessed the toxicological responses to aerosols from this NVP. Responses induced by IS1.0(TT)were compared to those from a 3R4F reference cigarette, using in vitro test methods which included regulatory genetic toxicological assays as well as some more contemporary screening approaches. The experimental conditions were designed to facilitate the testing of aerosol from this vaping product at doses that in most cases greatly exceeded those of the 3R4F comparator showed little to no toxicological responses and demonstrated significantly reduced effects in these in vitro assays when compared to 3R4F. Furthermore, the extreme doses tested in the present study indicate that the toxicant profile of this NVP translates to lower biological activity in vitro, and suggests that the absolute risk hazard level associated with electronic cigarettes can be reduced through continuous improvement as the technology evolves.
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Key Words
- ACM, aerosol collected mass
- ALI, air-liquid interface
- ANOVA, analysis of variance
- ARE, antioxidant response element
- Aerosol
- AqE, aerosol aqueous extract
- AqE, aqueous aerosol extracts
- CRM81, CORESTA recommended method number 81
- Cigarette
- DCF, 2′,7′ dichlorodihydrofluorescein
- DMSO, dimethyl sulfoxide
- DSB, double-strand break
- Electronic cigarette
- FDA, US Food and Drug Administration
- GEF, global evaluation factor
- GSH, glutathione (reduced form)
- HCI, Health Canada Intense
- HUVEC, human umbilical vein endothelial cell
- ISO, International Organisation for Standardisation
- IVMn, in vitro micronucleus
- In vitro
- MF, mutant frequency
- MLA, mouse lymphoma assay
- NASEM, US National Academy of Sciences, Engineering and Medicine
- NHBE, normal human bronchial epithelial
- NRU, neutral red uptake
- NVP, new vapour product
- RWD, relative wound density
- S9, post-mitochondrial supernatant
- TPA, 12-O-tetradecanoylphorbol-13-acetate
- TPM, total particulate matter
- TobReg, WHO Study Group on Tobacco Product Regulation
- WA, whole aerosol
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Verrastro I, Haswell L, Corke S, Baxter A, Thorne D, Breheny D, Minet E, Gaca M. In vitro toxicogenomic and proteomic assessment of e-cigarette aerosol compared to cigarette smoke. Toxicol Lett 2018. [DOI: 10.1016/j.toxlet.2018.06.937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Breheny D, Oke O, Camacho O, Pant K, Bruce S, LaForce M, Celestin N. Application of the Bhas 42 cell transformation assay to the assessment of novel tobacco products. Toxicol Lett 2015. [DOI: 10.1016/j.toxlet.2015.08.714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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