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Cordery S, Thompson K, Stevenson M, Simms L, Chapman F, Grandolfo E, Malt L, Weaver S, Fearon IM, Nahde T. The Product Science of Electrically Heated Tobacco Products: An Updated Narrative Review of the Scientific Literature. Cureus 2024; 16:e61223. [PMID: 38939262 PMCID: PMC11209752 DOI: 10.7759/cureus.61223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2024] [Indexed: 06/29/2024] Open
Abstract
Heated tobacco products represent a novel category of tobacco products in which a tobacco consumable is heated to a temperature that releases nicotine from the tobacco leaf but not to a temperature sufficient to cause combustion. Heated tobacco products may therefore have the potential to be a less harmful alternative for adult smokers who would otherwise continue to smoke cigarettes, as their use should result in exposure to substantially fewer and lower levels of toxicants. This update represents a two-year extension to our previous narrative review, which covered peer-reviewed journal articles published up to August 31, 2021. The scientific evidence published between 2021 and 2023 continues to indicate that aerosols produced from heated tobacco products contain fewer and substantially lower levels of harmful and potentially harmful constituents and that these observed reductions consistently translate to reduced biological effects in both in vitro and in vivo toxicological studies. Biomarker and clinical data from studies in which product use is controlled within a clinical setting continue to suggest changes in levels of biomarkers of exposure, biomarkers of potential harm, and clinical endpoints indicating the potential for reduced harm with switching to exclusive use of heated tobacco products in adult smokers. Overall, the available peer-reviewed scientific evidence continues to indicate that heated tobacco products offer promise as a potentially less harmful alternative to cigarettes, and as such, the conclusions of our original narrative review remain valid.
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Affiliation(s)
- Sarah Cordery
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Keith Thompson
- Independent Scientific Consultant, Elucid8 Holdings Ltd., Coleraine, GBR
| | - Matthew Stevenson
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Liam Simms
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Fiona Chapman
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Erika Grandolfo
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Layla Malt
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Sarah Weaver
- Group Science and Regulatory Affairs, Imperial Brands Plc., Bristol, GBR
| | - Ian M Fearon
- Scientific Research, whatIF? Consulting Ltd., Harwell, GBR
| | - Thomas Nahde
- Group Science and Regulatory Affairs, Imperial Brands Reemtsma, Hamburg, DEU
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2
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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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Yu F, Bishop E, Miazzi F, Evans R, Smart D, Breheny D, Thorne D. Multi-endpoint in vitro toxicological assessment of snus and tobacco-free nicotine pouch extracts. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 895:503738. [PMID: 38575247 DOI: 10.1016/j.mrgentox.2024.503738] [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: 01/16/2024] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 04/06/2024]
Abstract
'Modern' oral tobacco-free nicotine pouches (NPs) are a nicotine containing product similar in appearance and concept to Swedish snus. A three-step approach was taken to analyse the biological effects of NPs and snus extracts in vitro. ToxTracker was used to screen for biomarkers for oxidative stress, cell stress, protein damage and DNA damage. Cytotoxicity, mutagenicity, and genotoxicity were assessed in the following respective assays: Neutral Red Uptake (NRU), Ames and Mouse Lymphoma Assay (MLA). Targeted analysis of phosphorylation signalling and inflammatory markers under non-toxic conditions was used to investigate any potential signalling pathways or inflammatory response. A reference snus (CRP1.1) and four NPs with various flavours and nicotine strengths were assessed. Test article extracts was generated by incubating one pouch in 20 mL of media (specific to each assay) with the inclusion of the pouch material. NP extracts did not induce any cytotoxicity or mutagenic response, genotoxic response was minimal and limited signalling or inflammatory markers were induced. In contrast, CRP1.1 induced a positive response in four toxicological endpoints in the absence of S9: Srxn1 (oxidative stress), Btg2 (cell stress), Ddit3 (protein damage) and Rtkn (DNA damage), and three endpoints in presence of S9: Srxn1, Ddit3 and Rtkn. CRP1.1 was genotoxic when assessed in MLA and activated signalling pathways involved in proliferation and cellular stress and specifically induced phosphorylation of c-JUN, CREB1, p53, p38 MAPK and to a lesser extent AKT1S1, GSK3α/β, ERK1/2 and RSK1 in a dose-dependent manner. CRP 1.1 extracts resulted in the release of several inflammatory mediators including cytokines IL-1α, IL5, IL6, IL8, IL-1RA, MIF and TNF-β, receptor IL-2RA, and growth factors FGF-basic, VEGF and M-CSF. In conclusion these assays contribute to the weight of evidence assessment of the potential comparative health risks of NPs and snus.
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Affiliation(s)
- Fan Yu
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - Emma Bishop
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK.
| | - Fabio Miazzi
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - Rhian Evans
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - David Smart
- B.A.T. (Investments) Limited, Regents Park Road, Millbrook, Southampton SO15 8TL, UK
| | - 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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4
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An YJ, Kim YH. Assessment of toxicological validity using tobacco emission condensates: A comparative analysis of emissions and condensates from 3R4F reference cigarettes and heated tobacco products. ENVIRONMENT INTERNATIONAL 2024; 185:108502. [PMID: 38368717 DOI: 10.1016/j.envint.2024.108502] [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: 12/07/2023] [Revised: 01/19/2024] [Accepted: 02/12/2024] [Indexed: 02/20/2024]
Abstract
The tobacco emission condensate, henceforth referred to as "tobacco condensate," plays a critical role in assessing the toxicity of tobacco products. This condensate, derived from tobacco emissions, provides an optimized liquid concentrate for storage and concentration control. Thus, the validation of its constituents is vital for toxicity assessments. This study used tobacco condensates from 3R4F cigarettes and three heated tobacco product (HTP) variants to quantify and contrast organic compounds (OCs) therein. The hazard index (HI) for tobacco emissions and condensates was determined to ascertain the assessment validity. The total particulate matter (TPM) for 3R4F registered at 17,667 μg cig-1, with its total OC (TOC) at 3777 μg cig-1. HTPs' TPM and TOC were 9342 ± 1918 μg cig-1 and 5258 ± 593 μg stick-1, respectively. 3R4F's heightened TPM likely arises from tar, while HTPs' OC concentrations are influenced by vegetable glycerin (2236-2688 μg stick-1) and propylene glycol (589-610 μg stick-1). During the condensation process, a substantial proportion of OCs in 3R4F smoke underwent significant concentration decreases, in contrast to HTPs, where fewer than half of the examined OCs exhibited notable concentration declines. The HI for tobacco emissions exhibited a marginally higher value compared to tobacco condensate, with variations ranging from 7.92% (HTPs) to 18.6% (3R4F), denoting a minimal differential. These observations emphasize the importance of accurate OC recovery techniques to maintain the validity and reliability of toxicity assessments based on tobacco condensates. This study not only deepens the comprehension of chemical behaviors in tobacco products but also establishes a novel benchmark for their toxicity evaluation, with profound implications for public health strategies and consumer protection.
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Affiliation(s)
- Young-Ji An
- Department of Environment & Energy, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea
| | - Yong-Hyun Kim
- Department of Environment & Energy, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; School of Civil, Environmental, Resources and Energy Engineering, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Soil Environment Research Center, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
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5
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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] [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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6
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Hendriks G, Adriaens E, Allemang A, Clements J, Cole G, Derr R, Engel M, Hamel A, Kidd D, Kellum S, Kiyota T, Myhre A, Naëssens V, Pfuhler S, Roy M, Settivari R, Schuler M, Zeller A, van Benthem J, Vanparys P, Kirkland D. Interlaboratory validation of the ToxTracker assay: An in vitro reporter assay for mechanistic genotoxicity assessment. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2024; 65:4-24. [PMID: 38545858 DOI: 10.1002/em.22592] [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: 11/17/2023] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 04/11/2024]
Abstract
ToxTracker is a mammalian cell reporter assay that predicts the genotoxic properties of compounds with high accuracy. By evaluating induction of various reporter genes that play a key role in relevant cellular pathways, it provides insight into chemical mode-of-action (MoA), thereby supporting discrimination of direct-acting genotoxicants and cytotoxic chemicals. A comprehensive interlaboratory validation trial was conducted, in which the principles outlined in OECD Guidance Document 34 were followed, with the primary objectives of establishing transferability and reproducibility of the assay and confirming the ability of ToxTracker to correctly classify genotoxic and non-genotoxic compounds. Reproducibility of the assay to predict genotoxic MoA was confirmed across participating laboratories and data were evaluated in terms of concordance with in vivo genotoxicity outcomes. Seven laboratories tested a total of 64 genotoxic and non-genotoxic chemicals that together cover a broad chemical space. The within-laboratory reproducibility (WLR) was up to 98% (73%-98% across participants) and the overall between-laboratory reproducibility (BLR) was 83%. This trial confirmed the accuracy of ToxTracker to predict in vivo genotoxicants with a sensitivity of 84.4% and a specificity of 91.2%. We concluded that ToxTracker is a robust in vitro assay for the accurate prediction of in vivo genotoxicity. Considering ToxTracker's robust standalone accuracy and that it can provide important information on the MoA of chemicals, it is seen as a valuable addition to the regulatory in vitro genotoxicity battery that may even have the potential to replace certain currently used in vitro battery assays.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Jan van Benthem
- National Institute for Public Health and the Environment, The Netherlands
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7
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Menz J, Götz ME, Gündel U, Gürtler R, Herrmann K, Hessel-Pras S, Kneuer C, Kolrep F, Nitzsche D, Pabel U, Sachse B, Schmeisser S, Schumacher DM, Schwerdtle T, Tralau T, Zellmer S, Schäfer B. Genotoxicity assessment: opportunities, challenges and perspectives for quantitative evaluations of dose-response data. Arch Toxicol 2023; 97:2303-2328. [PMID: 37402810 PMCID: PMC10404208 DOI: 10.1007/s00204-023-03553-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/21/2023] [Indexed: 07/06/2023]
Abstract
Genotoxicity data are mainly interpreted in a qualitative way, which typically results in a binary classification of chemical entities. For more than a decade, there has been a discussion about the need for a paradigm shift in this regard. Here, we review current opportunities, challenges and perspectives for a more quantitative approach to genotoxicity assessment. Currently discussed opportunities mainly include the determination of a reference point (e.g., a benchmark dose) from genetic toxicity dose-response data, followed by calculation of a margin of exposure (MOE) or derivation of a health-based guidance value (HBGV). In addition to new opportunities, major challenges emerge with the quantitative interpretation of genotoxicity data. These are mainly rooted in the limited capability of standard in vivo genotoxicity testing methods to detect different types of genetic damage in multiple target tissues and the unknown quantitative relationships between measurable genotoxic effects and the probability of experiencing an adverse health outcome. In addition, with respect to DNA-reactive mutagens, the question arises whether the widely accepted assumption of a non-threshold dose-response relationship is at all compatible with the derivation of a HBGV. Therefore, at present, any quantitative genotoxicity assessment approach remains to be evaluated case-by-case. The quantitative interpretation of in vivo genotoxicity data for prioritization purposes, e.g., in connection with the MOE approach, could be seen as a promising opportunity for routine application. However, additional research is needed to assess whether it is possible to define a genotoxicity-derived MOE that can be considered indicative of a low level of concern. To further advance quantitative genotoxicity assessment, priority should be given to the development of new experimental methods to provide a deeper mechanistic understanding and a more comprehensive basis for the analysis of dose-response relationships.
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Affiliation(s)
- Jakob Menz
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany.
| | - Mario E Götz
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Ulrike Gündel
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Rainer Gürtler
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Kristin Herrmann
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Stefanie Hessel-Pras
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Carsten Kneuer
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Franziska Kolrep
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Dana Nitzsche
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Ulrike Pabel
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Benjamin Sachse
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Sebastian Schmeisser
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - David M Schumacher
- Department of Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Tanja Schwerdtle
- German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Tewes Tralau
- Department of Pesticides Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Sebastian Zellmer
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Bernd Schäfer
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
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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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9
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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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