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Keyser BM, Leverette R, McRae R, Wertman J, Shutsky T, Jordan K, Szeliga K, Makena P. In vitro toxicological evaluation of glo menthol and non-menthol heated tobacco products. Toxicology 2024; 504:153801. [PMID: 38614204 DOI: 10.1016/j.tox.2024.153801] [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: 03/26/2024] [Revised: 04/05/2024] [Accepted: 04/08/2024] [Indexed: 04/15/2024]
Abstract
Heated tobacco products (HTPs) are non-combustible, inhaled tobacco products that generate an aerosol with fewer and lower levels of toxicants, with a potential to reduce risk relative to cigarette smoking. Here, we assessed in vitro toxicological effects of three menthol (glo neo neoCLICK, neo Smooth Menthol and Fresh Menthol) and one non-menthol (neo Smooth Tobacco) variants of glo HTP, along with market comparators for cigarettes and HTPs. Limited chemical characterization of the study products revealed significantly lower levels of acetaldehyde, acrolein, crotanaldehyde and formaldehyde in test samples from HTPs than those from cigarettes. The glo HTPs were non-mutagenic in the bacterial reverse mutagenesis assay. Although, the whole aerosol exposures of glo HTPs were classified as genotoxic in the in vitro micronucleus assay, and cytotoxic in the NRU (monolayer) and MTT (3 dimensional EpiAirway™ tissues) assays, the cigarette comparators were the most toxic study products in each of these assessments. Further, glo HTPs elicited oxidative stress responses only at the highest dose tested, whereas the cigarette comparators were potent inducers of oxidative stress at substantially lower doses in the EpiAirway tissues. The comparator (non-glo) HTP results were similar to the glo HTPs in these assays. Thus, the glo HTPs exhibit substantially lower toxicity compared to cigarettes.
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Affiliation(s)
- Brian M Keyser
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA.
| | - Robert Leverette
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - Reagan McRae
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - John Wertman
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - Tom Shutsky
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - Kristen Jordan
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - Ken Szeliga
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
| | - Patrudu Makena
- RAI Services Company; Scientific & Regulatory Affairs, 401 North Main Street, Winston-Salem, NC 27101, USA
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2
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Crooks I, Clements J, Curren R, Guo X, Hollings M, Lloyd M, Smart D, Thorne D, Weber E, Moore M. Key Challenges for In Vitro Testing of Tobacco Products for Regulatory Applications: Recommendations for the In Vitro Mouse Lymphoma Assay. Altern Lab Anim 2024; 52:42-59. [PMID: 38055860 DOI: 10.1177/02611929231219153] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
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 traditional tobacco and various tobacco and nicotine next-generation products (NGPs), including Heated Tobacco Products (HTPs) and Electronic Nicotine Delivery Systems (ENDS). This report was developed by a working group composed of attendees of the seventh IIVS workshop, 'Approaches and recommendations for conducting the mouse lymphoma gene mutation assay (MLA) and introduction to in vitro disease models', which was held virtually on 21-23 June 2022. This publication provides a background overview of the MLA, and includes the description of assay conduct and data interpretation, key challenges and recommended best practices for evaluating tobacco and nicotine products, with a focus on the evaluation of NGPs, and a summary of how the assay has been used to evaluate and compare tobacco and nicotine products.
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Affiliation(s)
- Ian Crooks
- B.A.T. (Investments) Limited, Southampton, UK
| | | | - Rodger Curren
- Institute for In Vitro Sciences, Gaithersburg, MD, USA
| | - Xiaoqing Guo
- National Center for Toxicological Research, Jefferson, AR, USA
| | | | - Mel Lloyd
- Labcorp Early Development Services, Harrogate, UK
| | - Daniel Smart
- Philip Morris International R&D, Philip Morris Products S.A., Neuchatel, Switzerland
| | | | - Elisabeth Weber
- Oekolab Ges. F. Umweltanalytik, A member of the JT International Group of Companies, Vienna, Austria
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3
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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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4
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Dempsey R, Rodrigo G, Vonmoos F, Gunduz I, Belushkin M, Esposito M. Preliminary toxicological assessment of heated tobacco products: A review of the literature and proposed strategy. Toxicol Rep 2023; 10:195-205. [PMID: 36748021 PMCID: PMC9898577 DOI: 10.1016/j.toxrep.2023.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/20/2022] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
Heated tobacco products (HTP) have become increasingly common in many countries worldwide. The principle of heating tobacco, without combustion, to produce a nicotine-containing aerosol with remarkably reduced levels of other known toxins, compared to combusted tobacco cigarettes, is now well established. As these products are intended as alternatives to traditional combusted products, during the early stages of their development, it is important for manufacturers to ensure that the design of the product does not lead to any unintentionally increased or new risk for the consumer, compared to the traditional products that consumers seek to replace. There is limited guidance from tobacco product regulations concerning the requirements for performing such preliminary toxicological assessments. Here, we review the published literature on studies performed on HTPs in the pursuit of such data, outline a proposed approach that is consistent with regulatory requirements, and provide a logical approach to the preliminary toxicological assessment of HTPs.
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Affiliation(s)
- Ruth Dempsey
- RD Science Speaks Consultancy Sàrl, Le Mont sur Lausanne, Switzerland,Corresponding authors.
| | - Gregory Rodrigo
- PMI R&D, Philip Morris Products S.A., Rue des Usines 56, 2000 Neuchâtel, Switzerland,Corresponding authors.
| | - Florence Vonmoos
- PMI R&D, Philip Morris Products S.A., Rue des Usines 56, 2000 Neuchâtel, Switzerland
| | - Irfan Gunduz
- PMI R&D, Philip Morris Products S.A., Rue des Usines 56, 2000 Neuchâtel, Switzerland
| | - Maxim Belushkin
- PMI R&D, Philip Morris Products S.A., Rue des Usines 56, 2000 Neuchâtel, Switzerland
| | - Marco Esposito
- PMI R&D, Philip Morris Products S.A., Rue des Usines 56, 2000 Neuchâtel, Switzerland
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5
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Chemical and in vitro toxicological comparison of emissions from a heated tobacco product and the 1R6F reference cigarette. Toxicol Rep 2023; 10:281-292. [PMID: 36876026 PMCID: PMC9976195 DOI: 10.1016/j.toxrep.2023.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 02/06/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
It has previously been found that, compared with cigarette smoke, the aerosols generated by heated tobacco products contain fewer and lower harmful and potentially harmful constituents (HPHCs) and elicit lower biological activity in in vitro models and lower smoking-related exposure biomarker levels in clinical studies. It is important to accumulate such scientific evidences for heated tobacco products with a novel heating system, because different heating system may affect the quantitative aspect of the amount of HPHCs and the qualitative aspect of the biological activity of the aerosol generated. Here, the chemical properties of, and toxicological responses to aerosols emitted by DT3.0a, a new heated tobacco product with a novel heating system, and cigarette smoke (CS) were compared, using chemical analyses, in vitro battery (standardized genotoxicity and cytotoxicity) assays, and mechanistic (ToxTracker and two-dimensional cell culture) assays. Regular- and menthol-flavored DT3.0a and standard 1R6F reference cigarettes were tested. Selected HPHC yields were lower in DT3.0a aerosol than 1R6F CS. The genotoxicity-related assays indicated that DT3.0a aerosol was not genotoxic, regardless of metabolic activation. The other biological assays indicated that less cytotoxicity induction and oxidative stress response were elicited by DT3.0a aerosol compared with 1R6F CS. Similar results were found for both regular and menthol DT3.0a. Like previous reports for heated tobacco products with other heating systems, the results of this study indicated that DT3.0a aerosols have chemical and biological properties less likely to be harmful than 1R6F CS.
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Key Words
- ACM, aerosol collected mass
- ARE, anti-oxidant responsive element
- AqE, aqueous extract
- BDL, below detection limit
- CMF-PBS, calcium- and magnesium-free phosphate buffered saline
- CS, cigarette smoke
- Cytotoxicity
- DT3.0a, Direct Heating Tobacco System Platform 3 generation 3 version a
- GFP, green fluorescent protein
- GVP, gas-vapor phase
- Genotoxicity
- HPHCs
- HPHCs, harmful and potentially harmful constituents
- HTP, heated tobacco product
- Heated tobacco product
- IC50, half maximal inhibitory concentration
- ISO, International Organization for Standardization
- In vitro
- LOD, limit of detection
- LOQ, limit of quantification
- MLA, mouse lymphoma assay
- MN, micronucleus
- MRTP, modified risk tobacco product
- NQ, not quantified
- NRU, neutral red uptake
- Oxidative stress
- ROS, reactive oxygen species
- THP, tobacco heating product
- THS, tobacco heating system
- TPM, total particulate matter
- mES, mouse embryonic stem
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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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Chapman F, Sticken ET, Wieczorek R, Pour SJ, Dethloff O, Budde J, Rudd K, Mason E, Czekala L, Yu F, Simms L, Nahde T, O'Connell G, Stevenson M. Multiple endpoint in vitro toxicity assessment of a prototype heated tobacco product indicates substantially reduced effects compared to those of combustible cigarette. Toxicol In Vitro 2022; 86:105510. [DOI: 10.1016/j.tiv.2022.105510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/22/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022]
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Yu SJ, Kwon MK, Choi W, Son YS. Preliminary study on the effect of using heat-not-burn tobacco products on indoor air quality. ENVIRONMENTAL RESEARCH 2022; 212:113217. [PMID: 35381261 DOI: 10.1016/j.envres.2022.113217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/25/2022] [Accepted: 03/27/2022] [Indexed: 06/14/2023]
Abstract
In this study, the effect of the use of heat-not-burn (HnB) products on indoor air quality (IAQ) was evaluated. To do this, the concentrations of nicotine, propylene glycol (PG), and vegetable glycerin (VG) directly emitted when using HnB products were analyzed and compared to those from conventional cigarettes. Furthermore, the levels of VOCs, aldehydes, nanoparticle, and particulate matter (PM) detected when subjects used HnB products in the exposure chamber were evaluated the effect on IAQ. As a result, the range of nicotine levels transferred by HnB products (0.8-1.2 mg cigarette-1) is lower than that by conventional cigarettes (2.4-3.6 mg cigarette-1). On the other hand, the range of VG levels emitted from HnB products (3.1-5.9 mg cigarette-1) were higher than that emitted from conventional cigarettes (0.6-3.0 mg cigarette-1). In addition, although the amount generated from HnB products was small compared to those from conventional cigarettes, various kinds of VOCs, aldehydes, nanoparticle and PM were produced, and these were confirmed to affect IAQ.
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Affiliation(s)
- Seong-Ji Yu
- Division of Earth Environmental System Science, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, South Korea
| | - Min-Ku Kwon
- Division of Earth Environmental System Science, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, South Korea
| | - Wonsik Choi
- Department of Environmental Atmospheric Sciences, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, South Korea
| | - Youn-Suk Son
- Department of Environmental Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan, 48513, South Korea.
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9
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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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Goodall S, Gale N, Thorne D, Hadley S, Prasad K, Gilmour I, Miazzi F, Proctor C. Evaluation of behavioural, chemical, toxicological and clinical studies of a tobacco heated product glo™ and the potential for bridging from a foundational dataset to new product iterations. Toxicol Rep 2022; 9:1426-1442. [PMID: 36561950 PMCID: PMC9764197 DOI: 10.1016/j.toxrep.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/25/2022] Open
Abstract
Background Tobacco Heating Products (THPs) are tobacco products that heat rather than burn tobacco with temperatures less than 350 °C. Because of this operating principle, they produce substantially fewer and lower levels of tobacco smoke toxicants than combustible cigarette smoke produced when tobacco is burnt, which occurs at much higher temperatures of around 900 °C. This paper analyses data on a THP, glo™, and assesses whether its use would result in reduced health risks compared to the health risks of smoking cigarettes. It also looks at the possibility of bridging datasets across the different variants of the glo™ product. Methods The approach is to consider whether datasets from behavioural, chemical, toxicological and clinical studies provide consistent findings of reductions in toxicant exposure with glo™ use by subjects who switch completely from smoking cigarettes to using glo™ and whether these reductions are similar to those who stop smoking cigarettes without switching to glo™ or any other tobacco or nicotine product. We also examine the similarities and differences of different versions of the glo™ product and benchmark it against a THP from another manufacturer. Results The studies indicate that the use of the glo™ results in substantial and prolonged reductions in toxicant exposure for smokers who switch to glo™ completely. A long-term clinical study shows substantial reductions in toxicant exposure over a period of time, similar to reduction of some biomarkers of exposure found following smoking cessation without switching to glo™ or any other tobacco product, and biomarkers of potential harm trending in a favourable manner for both groups that switch to glo™ and that quit all tobacco and nicotine use. Data suggests that all iterations of glo™ result in substantial reductions in toxicant exposure compared to smoking cigarettes and that bridging across datasets is feasible. Conclusions Given the accumulated scientific data summarised in this paper, and particularly the findings from a long-term clinical study, the data demonstrate that glo™ is a reduced exposure product compared to combustible cigarettes and is reasonably deemed to reduce the risk of smoking-related diseases and supports the conclusion that smokers who would have otherwise continued to smoke and instead switch entirely to THP glo™ use, will reduce their relative risk of developing smoking-related diseases as compared to continued smoking. The extent of reduction in risk compared to continuing to smoke is likely to vary by smoking-related disease and by an individuals' smoking history, other risk factors and an individual's susceptibility to disease. Use of the THP will present some level of increased health risk as compared to cessation of tobacco and nicotine products and will cause dependence. As long as the principles of heat-not-burn are maintained, THP use will result in substantially reduced exposure to smoke toxicants as compared to continued conventional cigarette smoking. It is possible to use bridging or read across to apply these conclusions to new iterations of the glo™ product, extending the utility and validity of the evidence generated through study of prior iterations.
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Mortazavi SA, Bevelacqua JJ, Rafiepour P, Ghadimi-Moghadam A, Saraie P, Jooyan N, Mortazavi SH, Javad Mortazavi SM, Welsh JS. Revisiting the Paradox of Smoking: Radioactivity in Tobacco Smoke or Suppressing the SARS-CoV-2 Receptor, Angiotensin-Converting Enzyme 2, via Aryl-Hydrocarbon Receptor Signal? Dose Response 2022; 20:15593258221075111. [PMID: 35392263 PMCID: PMC8980405 DOI: 10.1177/15593258221075111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 01/01/2022] [Indexed: 11/15/2022] Open
Abstract
Despite current controversies, some reports show a paradoxical mitigating effect associated with smoking in individuals with symptomatic COVID-19 compared to the general population. To explain the potential mechanisms behind the lower number of hospitalized COVID-19 patients, it has been hypothesized that cigarette smoking may reduce the odds of cytokine storm and related severe inflammatory responses through cholinergic-mediated anti-inflammatory mechanisms. Japanese scientists have recently identified a potential mechanism behind the lower numbers of COVID-19 cases amongst smokers compared to non-smokers. However, we believe that this mitigative effect may be due to the relatively high concentration of deposited energy of alpha particles emitted from naturally occurring radionuclides such as Po-210 in cigarette tobacco. Regarding COVID-19, other researchers and our team have previously addressed the anti-inflammatory and immune-modulating effects of low doses of ionizing radiation. MC-simulation using the Geant4 Monte Carlo toolkit shows that the radiation dose absorbed in a spherical cell with a radius of .9 μm for a single 5.5 MeV alpha particle is about 5.1 Gy. This energy deposition may trigger both anti-inflammatory and anti-thrombotic effects which paradoxically lower the risk of hospitalization due to COVID-19 in smokers.
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Affiliation(s)
| | | | - Payman Rafiepour
- Department of Nuclear Engineering, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | | | - Pooya Saraie
- Radiology Department, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Najmeh Jooyan
- Medical Physics and Engineering Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | | | - James S Welsh
- Department of Radiation Oncology Edward Hines Jr VA Hospital Hines, IL, USA
- Department of Radiation Oncology, Stritch School of Medicine, Loyola University, Chicago, IL, United States
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12
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The flavoring and not the nicotine content is a decisive factor for the effects of refill liquids of electronic cigarette on the redox status of endothelial cells. Toxicol Rep 2020; 7:1095-1102. [PMID: 32953462 PMCID: PMC7484539 DOI: 10.1016/j.toxrep.2020.08.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 11/21/2022] Open
Abstract
The pattern of the effect on Ea.hy926 redox status differs among flavored e-liquids. Tobacco flavored e-liquids increase ROS generation with concomitant increase in TBARS. Vanilla flavored e-liquids profile depends on the nicotine content. Apple/mint flavored e-liquids activate the cellular antioxidant defense. Flavorings and not the nicotine content play a key role in free radical generation.
Electronic cigarettes are constantly gaining ground as they are considered less harmful than conventional cigarettes, and there is also the perception that they may serve as a potential smoking cessation tool. Although the acute effects of electronic cigarette use have been extensively studied, the long-term potential adverse effects on human health remain largely unknown. It has been well-established that oxidative stress is involved in the development of various pathological conditions. So far, most studies on e-cigarettes concern the effects on the respiratory system while fewer have focused on the vascular system. In the present study, we attempted to reveal the effects of electronic cigarette refill liquids on the redox state of human endothelial cells (EA.hy926 cell line). For this purpose, the cytotoxic effect of three e-liquids with different flavors (tobacco, vanilla, apple/mint) and nicotine concentrations (0, 6, 12, 18 mg/ml) were initially examined for their impact on cell viability of EA.hy926 cells. Then, five redox biomarkers [reduced form of glutathione (GSH), reactive oxygen species (ROS), total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS) and protein carbonyls (CARBS)] were measured. The results showed a disturbance in the redox balance in favor of free radicals in tobacco flavored e-liquids while vanilla flavored e-liquids exhibited a more complex profile depending on the nicotine content. The most interesting finding of the present study concerns the apple/mint flavored e-liquids that seemed to activate the cellular antioxidant defense and, thus, to protect the cells from the adverse effects of free radicals. Conclusively, it appears that the flavorings and not the nicotine content play a key role in the oxidative stress-induced toxicity of the e-liquids.
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Key Words
- 8-OH-dG, 8-hydroxy-deoxyguanosine
- CARBS, protein carbonyls
- CO, carbon monoxide
- DCF-DA, 2′,7′-dichlorodihydrofluorescein diacetate
- DMEM, Dulbecco’s modified Eagle’s medium
- DNPH, 2,4-dinitrophenylhydrazine
- DPPH, 2,2-diphenyl-1-picrylhydrazyl
- DPPHH, 2,2-diphenyl-1-picrylhydrazine
- E-cigarettes
- E-liquids
- ENDS, electronic nicotine delivery systems
- EPR, electronic paramagnetic resonance
- Endothelial cells
- FSC, forward light scattering
- GSH
- GSH, reduced form of glutathione
- HCL, hydrochloric acid
- HCN, hydrogen cyanide
- MDA, malondialdehyde
- Oxidative stress
- PBS, phosphate buffered saline
- PG, propylene glycol
- ROS
- ROS, reactive oxygen species
- SSC, side light scattering
- TAC, total antioxidant capacity
- TBA, thiobarbituric acid
- TBARS, thiobarbituric acid reactive substances
- TCA, trichloroacetic acid
- Tris-HCl, trishydroxymethylaminomethane hydrochloride
- VG, vegetable glycerin
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Wieczorek R, Phillips G, Czekala L, Trelles Sticken E, O'Connell G, Simms L, Rudd K, Stevenson M, Walele T. A comparative in vitro toxicity assessment of electronic vaping product e-liquids and aerosols with tobacco cigarette smoke. Toxicol In Vitro 2020; 66:104866. [PMID: 32353510 DOI: 10.1016/j.tiv.2020.104866] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 11/18/2022]
Abstract
The use of electronic vaping products (EVPs) continues to increase worldwide among adult smokers in parallel with accumulating information on their potential toxicity and relative safety compared to tobacco smoke. At this time, in vitro assessments of many widely available EVPs are limited. In this study, an in vitro battery of established assays was used to examine the cytotoxic (Neutral red uptake), genotoxic (In vitro micronucleus) and mutagenic (Bacterial reverse mutation) responses of two commercial EVPs (blu GO™ disposable and blu PLUS+™ rechargeable) when compared to smoke from a reference cigarette (3R4F). In total, 12 commercial products were tested as e-liquids and as aerosols. In addition, two experimental base liquids containing 1.2% and 2.4% nicotine were also assessed to determine the effect of flavour and nicotine on all three assays. In the bacterial reverse mutation (Ames) and in vitro micronucleus (IVM) assays, exposures to e-liquids and EVP aerosols, with and without nicotine and in a range of flavourings, showed no mutagenic or genotoxic effects compared to tobacco smoke. The neutral red uptake (NRU) assay showed significantly reduced cytotoxicity (P < .05) for whole undiluted EVP aerosols compared to tobacco smoke, which by contrast was markedly cytotoxic even when diluted. The reduced in vitro toxicological responses of the EVPs add to the increasing body of scientific weight-of-evidence supporting the role of high-quality EVPs as a harm reduction tool for adult smokers.
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Affiliation(s)
- R Wieczorek
- Reemtsma Cigarettenfabriken GmbH - Imperial Brands, Albert-Einstein-Ring 7, 22761 Hamburg, Germany
| | - G Phillips
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK.
| | - L Czekala
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
| | - E Trelles Sticken
- Reemtsma Cigarettenfabriken GmbH - Imperial Brands, Albert-Einstein-Ring 7, 22761 Hamburg, Germany
| | - G O'Connell
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
| | - L Simms
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
| | - K Rudd
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
| | - M Stevenson
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
| | - T Walele
- Imperial Brands PLC, 121 Winterstoke Road, Bristol BS3 2LL, UK
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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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