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Alkhlaif Y, Shelton KL. Stimulus mediation, specificity and impact of menthol in rats trained to discriminate puffs of nicotine e-cigarette aerosol from nicotine-free aerosol. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06579-9. [PMID: 38519818 DOI: 10.1007/s00213-024-06579-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 03/15/2024] [Indexed: 03/25/2024]
Abstract
RATIONALE It is unclear if e-cigarettes have reduced abuse liability relative to traditional cigarettes, especially when considering advanced devices which deliver nicotine more efficiently. Translatable and predictive animal models are needed to addresses this question. OBJECTIVES Our goal was to explore the subjective stimulus effects of e-cigarettes by training rats to discriminate puffs of nicotine aerosol from vehicle aerosol using an aerosol delivery system designed to model e-cigarette use patterns in humans. METHODS Rats were trained to discriminate between ten, 10 s puffs of aerosol generated from 3 mg/ml nicotine e-liquid and nicotine-free e-liquid using a food-reinforced operant procedure. Following acquisition, tests were conducted to determine the specificity of the nicotine aerosol stimulus as well as the impact to the stimulus effects of nicotine resulting from the addition of menthol to e-liquid. RESULTS Rats learned the nicotine aerosol puff vs vehicle puff discrimination in a mean of 25 training sessions. Injected nicotine fully substituted for the stimulus effects of nicotine aerosol. The stimulus effects of nicotine aerosol were blocked by the nicotinic receptor antagonist mecamylamine. The nicotinic receptor partial agonist, varenicline as well as the stimulant d-amphetamine substituted more robustly for nicotine aerosol puffs than did the NMDA antagonist, ketamine. Menthol enhanced the stimulus effects of nicotine aerosol without altering nicotine blood plasma levels. CONCLUSIONS Nicotine aerosol puffs can function as a training stimulus in rats. The stimulus effects were CNS-mediated and receptor specific. Menthol appears to enhance the stimulus effects of nicotine aerosol through a pharmacodynamic rather than pharmacokinetic mechanism.
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Affiliation(s)
- Yasmin Alkhlaif
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, 410 North 12Th Street, Room 746D, Richmond, VA, 23298-0613, USA
| | - Keith L Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, 410 North 12Th Street, Room 746D, Richmond, VA, 23298-0613, USA.
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Sachdeva J, Karunananthan A, Shi J, Dai W, Kleinman MT, Herman D, Kloner RA. Flavoring Agents in E-cigarette Liquids: A Comprehensive Analysis of Multiple Health Risks. Cureus 2023; 15:e48995. [PMID: 38111420 PMCID: PMC10726647 DOI: 10.7759/cureus.48995] [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: 11/15/2023] [Indexed: 12/20/2023] Open
Abstract
The availability of a wide range of flavored e-cigarettes is one of the primary reasons for vaping initiation and persistent use among adolescents and young people. This plethora of flavors available on the market are crafted using different flavoring agents such as cinnamaldehyde, vanillin, benzaldehyde, ethyl maltol, menthol, and dimethylpyrazine. Recent studies have brought to light the potential risks associated with e-cigarette flavoring agents and their effects on various organ systems, both with and without nicotine. Research has demonstrated that flavoring agents can induce inflammation, endothelial dysfunction, epithelial barrier disruption, oxidative stress, DNA damage, electrophysiological alterations, immunomodulatory effects, and behavioral changes, even independently of nicotine. Notably, these negative outcomes adversely affect cardiovascular system by reducing cell viability, decreasing endothelial nitric oxide synthase, nitric oxide bioavailability, soluble guanylyl cyclase activity and cyclic guanosine monophosphate accumulation, impairing endothelial proliferation and tube formation, and altering vasoreactivity resulting in vascular dysfunction. In the heart, these agents decrease parasympathetic activity, induce depolarization of resting membrane potential, loss of rhythmicity, increase isovolumic relaxation time, and change in ventricular repolarization and ventricular tachyarrhythmias. It is found that the specific response elicited by flavoring agents in different organ systems varies depending on the flavor used, the concentration of the flavoring agent, and the duration of exposure. However, the literature on the effects of flavoring agents is currently limited, emphasizing the need for more preclinical and randomized clinical trials to gain a deeper understanding and provide further evidence of the harmful effects of flavored e-cigarette use. In summary, recent research suggests that flavoring agents themselves can have detrimental effects on the body. To fully comprehend these effects, additional preclinical and clinical studies are needed to explore the risks associated with flavored e-cigarette usage.
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Affiliation(s)
- Jaspreet Sachdeva
- Cardiovascular Sciences, Huntington Medical Research Institutes, Pasadena, USA
| | | | - Jianru Shi
- Cardiovascular Sciences, Huntington Medical Research Institutes, Pasadena, USA
| | - Wangde Dai
- Cardiovascular Sciences, Huntington Medical Research Institutes, Pasadena, USA
| | - Michael T Kleinman
- Environmental and Occupational Health, College of Health Sciences, University of California, Irvine, USA
| | - David Herman
- Environmental and Occupational Health, College of Health Sciences, University of California, Irvine, USA
| | - Robert A Kloner
- Cardiovascular Sciences, Huntington Medical Research Institutes, Pasadena, USA
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Gravely S, Yong HH, Reid JL, East KA, Liber AC, Michael Cummings K, Quah AC, Fong GT, Hammond D. An examination of quitting smoking as a reason for vaping by the type of nicotine vaping device used most often among adults who smoke and vape: Findings from the Canada, England and the United States 2020 ITC Smoking and Vaping Survey. Prev Med Rep 2023; 33:102201. [PMID: 37223550 PMCID: PMC10201827 DOI: 10.1016/j.pmedr.2023.102201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/25/2023] Open
Abstract
Several nicotine vaping product (NVP) device types are available to consumers, and many people who smoke report vaping to help them quit. This study included data from the Wave 3 (2020) ITC Smoking and Vaping Survey in the US, Canada, and England and included 2324 adults who were smoking cigarettes and vaping at least weekly. Device types currently used most often (disposables, cartridges/pods, or tank systems) were assessed using weighted descriptive statistics. Multivariable regression analyses were used to compare differences between respondents who reported vaping to quit smoking ('yes' vs. 'no/don't know') by device type, overall and by country. Overall, 71.3% of respondents reported vaping to help them quit smoking, with no country differences (p = 0.12). Those using tanks (78.7%, p < 0.001) and cartridges/pods (69.5%, p = 0.02) were more likely to report this reason for vaping than those using disposables (59.3%); respondents using tanks were also more likely than those using cartridges/pods (p = 0.001) to report this reason. By country, respondents in England using cartridges/pods or tanks (vs. disposables) were more likely to report vaping to quit smoking (with no difference between cartridges/pods and tanks). In Canada, respondents using tanks were more likely to report vaping to quit smoking than those using cartridges/pods or disposables (no difference between disposables and cartridges/pods). No significant differences by device type were found in the US. In conclusion, most adult respondents who smoked and vaped reported using either cartridges/pods or tanks, which were associated with greater odds of vaping for the purpose of quitting smoking versus disposables, with some country variations.
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Affiliation(s)
- Shannon Gravely
- Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Hua-Hie Yong
- School of Psychology, Deakin University, 1 Gheringhap Street, Geelong, Victoria 3220, Australia
| | - Jessica L. Reid
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Katherine A. East
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Department of Addictions, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, Addictions Sciences Building, 4 Windsor Walk, Denmark Hill, London SE5 8BB, UK
| | - Alex C. Liber
- Lombardi Comprehensive Cancer Center, Georgetown University, 3800 Reservoir Rd NW, Washington, DC 20007, USA
| | - K. Michael Cummings
- Department of Psychiatry & Behavioral Sciences, Medical University of South Carolina, 67 President St., Charleston, SC 29425, USA
| | - Anne C.K. Quah
- Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Geoffrey T. Fong
- Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
- Ontario Institute for Cancer Research, 661 University Ave., Toronto, ON M5G 0A3, Canada
| | - David Hammond
- School of Public Health Sciences, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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Tellez CS, Grimes MJ, Juri DE, Do K, Willink R, Dye WW, Wu G, Picchi MA, Belinsky SA. Flavored E-cigarette product aerosols induce transformation of human bronchial epithelial cells. Lung Cancer 2023; 179:107180. [PMID: 36989612 PMCID: PMC10159902 DOI: 10.1016/j.lungcan.2023.107180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 03/29/2023]
Abstract
OBJECTIVES E-cigarettes are the most commonly used nicotine containing products among youth. In vitro studies support the potential for e-cigarettes to cause cellular stress in vivo; however, there have been no studies to address whether exposure to e-liquid aerosols can induce cell transformation, a process strongly associated with pre-malignancy. We examined whether weekly exposure of human bronchial epithelial cell (HBEC) lines to e-cigarette aerosols would induce transformation and concomitant changes in gene expression and promoter hypermethylation. MATERIALS AND METHODS An aerosol delivery system exposed three HBEC lines to unflavored e-liquid with 1.2% nicotine, 3 flavored products with nicotine, or the Kentucky reference cigarette once a week for 12 weeks. Colony formation in soft agar, RNA-sequencing, and the EPIC Beadchip were used to evaluate transformation, genome-wide expression and methylation changes. RESULTS Jamestown e-liquid aerosol induced transformation of HBEC2 and HBEC26, while unflavored and Blue Pucker transformed HBEC26. Cigarette smoke aerosol transformed HBEC4 and HBEC26 at efficiencies up to 3-fold greater than e-liquids. Transformed clones exhibited extensive reprogramming of the transcriptome with common and distinct gene expression changes observed between the cigarette and e-liquids. Transformation by e-liquids induced alterations in canonical pathways implicated in lung cancer that included axonal guidance and NRF2. Gene methylation, while prominent in cigarette-induced transformed clones, also affected hundreds of genes in HBEC2 transformed by Jamestown. Many genes with altered expression or epigenetic-mediated silencing were also affected in lung tumors from smokers. CONCLUSIONS These studies show that exposure to e-liquid aerosols can induce a pre-malignant phenotype in lung epithelial cells. While the Food and Drug Administration banned the sale of flavored cartridge-based electric cigarettes, consumers switched to using flavored products through other devices. Our findings clearly support expanding studies to evaluate transformation potency for the major categories of e-liquid flavors to better inform risk from these complex mixtures.
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Affiliation(s)
- Carmen S. Tellez
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Marcie J. Grimes
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Daniel E. Juri
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Kieu Do
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Randy Willink
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Wendy W. Dye
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Guodong Wu
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Maria A. Picchi
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
| | - Steven A. Belinsky
- Lung Cancer Program Lovelace Biomedical Research Institute Albuquerque, NM
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Soulet S, Sussman RA. Critical Review of the Recent Literature on Organic Byproducts in E-Cigarette Aerosol Emissions. TOXICS 2022; 10:714. [PMID: 36548547 PMCID: PMC9787926 DOI: 10.3390/toxics10120714] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/03/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
We review the literature on laboratory studies quantifying the production of potentially toxic organic byproducts (carbonyls, carbon monoxide, free radicals and some nontargeted compounds) in e-cigarette (EC) aerosol emissions, focusing on the consistency between their experimental design and a realistic usage of the devices, as determined by the power ranges of an optimal regime fulfilling a thermodynamically efficient process of aerosol generation that avoids overheating and "dry puffs". The majority of the reviewed studies failed in various degrees to comply with this consistency criterion or supplied insufficient information to verify it. Consequently, most of the experimental outcomes and risk assessments are either partially or totally unreliable and/or of various degrees of questionable relevance to end users. Studies testing the devices under reasonable approximation to realistic conditions detected levels of all organic byproducts that are either negligible or orders of magnitude lower than in tobacco smoke. Our review reinforces the pressing need to update and improve current laboratory standards by an appropriate selection of testing parameters and the logistical incorporation of end users in the experimental design.
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Affiliation(s)
| | - Roberto A. Sussman
- Institute of Nuclear Sciences, National Autonomous University of Mexico, Mexico City 04510, Mexico
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Goniewicz ML, Stanton CA. Impact of flavour restricting policies on non-cigarette tobacco products. Tob Control 2022; 31:s159-s160. [PMID: 36328468 PMCID: PMC9664120 DOI: 10.1136/tc-2022-057785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Maciej L Goniewicz
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, New York, USA
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