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Zong H, Hu Z, Li W, Wang M, Zhou Q, Li X, Liu H. Electronic cigarettes and cardiovascular disease: epidemiological and biological links. Pflugers Arch 2024:10.1007/s00424-024-02925-0. [PMID: 38376568 DOI: 10.1007/s00424-024-02925-0] [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: 01/04/2024] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/21/2024]
Abstract
Electronic cigarettes (e-cigarettes), as alternative nicotine delivery methods, has rapidly increased among youth and adults in recent years. However, cardiovascular safety is an important consideration regarding e-cigarettes usage. e-cigarette emissions, including nicotine, propylene glycol, flavorings, nitrosamine, and metals, might have adverse effects on cardiovascular health. A large body of epidemiological evidence has indicated that e-cigarettes are considered an independent risk factor for increased rates of cardiovascular disease occurrence and death. The incidence and mortality of various types of cardiovascular disease, such as cardiac arrhythmia, hypertension, acute coronary syndromes, and heart failure, have a modest growth in vapers (users of e-cigarettes). Although the underlying biological mechanisms have not been fully understood, studies have validated that oxidative stress, inflammation, endothelial dysfunction, atherosclerosis, hemodynamic effects, and platelet function play important roles in which e-cigarettes work in the human body. This minireview consolidates and discusses the epidemiological and biological links between e-cigarettes and various types of cardiovascular disease.
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Affiliation(s)
- Huiqi Zong
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zhekai Hu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Xicheng District, Beijing, 100053, China
| | - Weina Li
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Xicheng District, Beijing, 100053, China
| | - Mina Wang
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
- Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Qi Zhou
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China
| | - Xiang Li
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China.
| | - Hongxu Liu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, 100010, China.
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Thomas JE, Pasch KE, Nathan Marti C, Loukas A. Depressive symptoms prospectively increase risk for new onset cigarette and ENDS dependence symptoms. Addict Behav 2024; 148:107870. [PMID: 37776758 DOI: 10.1016/j.addbeh.2023.107870] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/30/2023] [Accepted: 09/24/2023] [Indexed: 10/02/2023]
Abstract
Little research has examined the new onset of cigarette and Electronic Nicotine Delivery System (ENDS) dependence symptoms among young adults. This study aims to 1) examine new onset cigarette and ENDS dependence symptoms over a 4.5-year period and 2) examine how depressive symptoms impact new onset dependence symptoms among young adults. Participants were drawn from 24 colleges in Texas who were participating in a multi-wave cohort study (2014-2019). The present study included 4536 participants aged 18-25 who did not report cigarette or ENDS dependence symptoms at wave 1 (64.1% female; 65.2% non-white; m age = 20.62 [SD = 1.80] at wave 1). Cox's regression models were employed to determine the hazard of new onset cigarette and ENDS dependence symptoms overall and the impact of depressive symptoms. Models controlled for sociodemographic factors and other tobacco product use. 14.4% of participants reported new onset cigarette dependence symptoms and 14.6% reported new onset ENDS dependence symptoms over the 4.5 years of the study. Depressive symptoms significantly predicted increased risk for new onset cigarette (HR = 1.30, CI = [1.21, 1.39]) and ENDS (HR = 1.20, CI = [1.12, 1.29]) dependence symptoms. Young adults exhibited dependence symptoms for cigarettes and ENDS products at similar rates across the 4.5 years of the study. Elevated depressive symptoms increased risk of new onset cigarette and ENDS dependence symptoms, advancing evidence for the self-medication hypothesis. Tobacco and nicotine prevention and cessation programs and messaging are needed particularly among young adults who experience depressive symptoms.
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Affiliation(s)
- Jacob E Thomas
- Department of Kinesiology and Health Education, The University of Texas at Austin, 2109 San Jacinto Blvd D3700, Austin, TX 78712, USA.
| | - Keryn E Pasch
- Department of Kinesiology and Health Education, The University of Texas at Austin, 2109 San Jacinto Blvd D3700, Austin, TX 78712, USA.
| | - C Nathan Marti
- Department of Kinesiology and Health Education, The University of Texas at Austin, 2109 San Jacinto Blvd D3700, Austin, TX 78712, USA.
| | - Alexandra Loukas
- Department of Kinesiology and Health Education, The University of Texas at Austin, 2109 San Jacinto Blvd D3700, Austin, TX 78712, USA.
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Noël A, Ghosh A. Carbonyl Profiles of Electronic Nicotine Delivery System (ENDS) Aerosols Reflect Both the Chemical Composition and the Numbers of E-Liquid Ingredients-Focus on the In Vitro Toxicity of Strawberry and Vanilla Flavors. Int J Environ Res Public Health 2022; 19:16774. [PMID: 36554655 PMCID: PMC9779252 DOI: 10.3390/ijerph192416774] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Propylene glycol (PG) and glycerin (G) are the most widely used humectants in electronic nicotine delivery system (ENDS) devices. Carbonyls are present in aerosols produced when ENDS devices heat PG and G. Whether aerosolized PG and G are innocuous to the lungs has not been established. Here, we determined the chemical profiles of ENDS aerosols containing three humectant ratios (30/70, 50/50 and 70/30, PG/VG), for three flavors (strawberry, vanilla and Catalan cream) containing either 12 or 18 mg/mL of nicotine. Additionally, we examined the in vitro toxicity of the strawberry- and vanilla-flavored ENDS aerosol in human lung epithelial cells (BEAS-2B) exposed at the air-liquid interface for 1 h. For strawberry- and vanilla-flavored aerosols produced by a 3rd-generation ENDS device with the same PG/G ratio, the e-liquid nicotine content of 12 and 18 mg/mL did not transfer to the aerosol with substantial differences in concentrations. Our data also indicate the presence of carbonyls in all three flavored e-cig aerosols analyzed, with levels exceeding 1 µg/puff for acetone, butyraldehyde, and acetaldehyde, in strawberry-, vanilla, and Catalan cream-flavored e-cig aerosols, respectively. Furthermore, closed-system ENDS of the fourth generation emitted trace levels of carbonyls in the aerosols (<0.3 µg/puff), while open-system tank-style ENDS of the third generation produced elevated levels of harmful chemicals, including acrolein (>1 µg/puff), formaldehyde (>5 µg/puff), and m- & p-tolualdehyde (>4 µg/puff). Moreover, under non-cytotoxic conditions, BEAS-2B cells exposed to strawberry-flavored aerosols exhibited significantly increased reactive oxygen and nitric oxide species (ROS/NOS) levels in cell media compared to air controls, while vanilla-flavored ENDS aerosols up-regulated the expression of pro-inflammatory and oxidative stress markers. Our data suggest (a) that ENDS aerosol chemical composition will vary based upon the presence and concentration of the initial e-liquid ingredients, with a pronounced impact of the flavoring components; and (b) short-term exposures to flavored ENDS aerosols may impair lung cells' redox signaling in a flavor-specific manner.
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Hong SW, Teesdale-Spittle P, Page R, Truman P. A review of monoamine oxidase (MAO) inhibitors in tobacco or tobacco smoke. Neurotoxicology 2022; 93:163-172. [PMID: 36155069 DOI: 10.1016/j.neuro.2022.09.008] [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: 05/12/2022] [Revised: 09/14/2022] [Accepted: 09/21/2022] [Indexed: 10/14/2022]
Abstract
Tobacco smoking is reputed to be the most difficult addiction of all to give up, and nicotine has been noted as the major addictive agent in tobacco smoke. However, research shows that nicotine addiction is due to more than nicotine alone. One hypothesis is that monoamine oxidase (MAO) inhibition from non-nicotinic components in, or derived from, tobacco smoke contributes to nicotine addiction. Harman and norharman, have been recognised as major and potent MAO inhibitors in tobacco smoke, but these two inhibitors together comprise perhaps less than 10% of the total MAO A inhibitory activity in cigarette smoke suggesting other unidentified components may make significant contributions to total inhibitory activity. Therefore, we reviewed an index of the chemical components of tobacco and tobacco smoke and identified those known to be MAO inhibitors. Amongst these inhibitors, phenols and phenolic acids with MAO inhibitory activity are commonly reversible and selective MAO A inhibitors, whereas trans,trans-farnesol, 2-methyl-1,4-naphthoquinone (menadione), 1,4-naphthoquinone, scopoletin, and diosmetin with MAO inhibitory activity are reversible and selective MAO B inhibitors. The compound, 1,4-benzoquinone is an irreversible MAO A inhibitor and to the best of our knowledge, this is the first irreversible MAO A inhibitor to be reported in tobacco smoke. MAO inhibitors have been used clinically to treat depression, anxiety, and Parkinson's disease. The MAO inhibitors identified from tobacco and tobacco smoke and summarized in this review, are potential pharmacological candidates to be investigated further. This review will enhance our knowledge of the way tobacco smoke affects MAO activity in smokers and will also be important in helping to understand nicotine addiction.
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Affiliation(s)
- Sa Weon Hong
- School of Health Sciences, Massey University, Wellington 6021, New Zealand.
| | - Paul Teesdale-Spittle
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Rachel Page
- School of Health Sciences, Massey University, Wellington 6021, New Zealand
| | - Penelope Truman
- School of Health Sciences, Massey University, Wellington 6021, New Zealand
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Sved AF, Weeks JJ, Grace AA, Smith TT, Donny EC. Monoamine oxidase inhibition in cigarette smokers: From preclinical studies to tobacco product regulation. Front Neurosci 2022; 16:886496. [PMID: 36051642 PMCID: PMC9424897 DOI: 10.3389/fnins.2022.886496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/21/2022] [Indexed: 11/13/2022] Open
Abstract
Monoamine oxidase (MAO) activity is reduced in cigarette smokers and this may promote the reinforcing actions of nicotine, thereby enhancing the addictive properties of cigarettes. At present, it is unclear how cigarette smoking leads to MAO inhibition, but preclinical studies in rodents show that MAO inhibition increases nicotine self-administration, especially at low doses of nicotine. This effect of MAO inhibition develops slowly, likely due to plasticity of brain monoamine systems; studies relying on acute MAO inhibition are unlikely to replicate what happens with smoking. Given that MAO inhibition may reduce the threshold level at which nicotine becomes reinforcing, it is important to consider this in the context of very low nicotine content (VLNC) cigarettes and potential tobacco product regulation. It is also important to consider how this interaction between MAO inhibition and the reinforcing actions of nicotine may be modified in populations that are particularly vulnerable to nicotine dependence. In the context of these issues, we show that the MAO-inhibiting action of cigarette smoke extract (CSE) is similar in VLNC cigarettes and cigarettes with a standard nicotine content. In addition, we present evidence that in a rodent model of schizophrenia the effect of MAO inhibition to enhance nicotine self-administration is absent, and speculate how this may relate to brain serotonin systems. These issues are relevant to the MAO-inhibiting effect of cigarette smoking and its implications to tobacco product regulation.
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Affiliation(s)
- Alan F. Sved
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
- *Correspondence: Alan F. Sved,
| | - Jillian J. Weeks
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
| | - Anthony A. Grace
- Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tracy T. Smith
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Eric C. Donny
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, United States
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Rendić SP, Crouch RD, Guengerich FP. Roles of selected non-P450 human oxidoreductase enzymes in protective and toxic effects of chemicals: review and compilation of reactions. Arch Toxicol 2022; 96:2145-2246. [PMID: 35648190 PMCID: PMC9159052 DOI: 10.1007/s00204-022-03304-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 03/25/2022] [Accepted: 04/26/2022] [Indexed: 12/17/2022]
Abstract
This is an overview of the metabolic reactions of drugs, natural products, physiological compounds, and other (general) chemicals catalyzed by flavin monooxygenase (FMO), monoamine oxidase (MAO), NAD(P)H quinone oxidoreductase (NQO), and molybdenum hydroxylase enzymes (aldehyde oxidase (AOX) and xanthine oxidoreductase (XOR)), including roles as substrates, inducers, and inhibitors of the enzymes. The metabolism and bioactivation of selected examples of each group (i.e., drugs, “general chemicals,” natural products, and physiological compounds) are discussed. We identified a higher fraction of bioactivation reactions for FMO enzymes compared to other enzymes, predominately involving drugs and general chemicals. With MAO enzymes, physiological compounds predominate as substrates, and some products lead to unwanted side effects or illness. AOX and XOR enzymes are molybdenum hydroxylases that catalyze the oxidation of various heteroaromatic rings and aldehydes and the reduction of a number of different functional groups. While neither of these two enzymes contributes substantially to the metabolism of currently marketed drugs, AOX has become a frequently encountered route of metabolism among drug discovery programs in the past 10–15 years. XOR has even less of a role in the metabolism of clinical drugs and preclinical drug candidates than AOX, likely due to narrower substrate specificity.
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Affiliation(s)
| | - Rachel D Crouch
- College of Pharmacy and Health Sciences, Lipscomb University, Nashville, TN, 37204, USA
| | - F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
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Harris AC, Muelken P, Alcheva A, Stepanov I, LeSage MG. Cigarette Smoke Extract, but Not Electronic Cigarette Aerosol Extract, Inhibits Monoamine Oxidase in vitro and Produces Greater Acute Aversive/Anhedonic Effects Than Nicotine Alone on Intracranial Self-Stimulation in Rats. Front Neurosci 2022; 16:868088. [PMID: 35712461 PMCID: PMC9196039 DOI: 10.3389/fnins.2022.868088] [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: 02/02/2022] [Accepted: 04/25/2022] [Indexed: 12/14/2022] Open
Abstract
Conventional tobacco cigarettes appear to have greater abuse liability than non-combusted products such as electronic cigarettes (ECs) and nicotine replacement therapy (NRT). This may be due to the higher levels of behaviorally active non-nicotine constituents [e.g., monoamine oxidase (MAO) inhibitors such as β-carbolines] in cigarette smoke (CS) compared to non-combusted products. To evaluate this hypothesis, the current studies compared the relative abuse liability of CS and EC aerosol extracts containing nicotine and a range of non-nicotine constituents to that of nicotine alone (NRT analog) using intracranial self-stimulation (ICSS) in rats. Effects of formulations on brain MAO activity in vitro and ex vivo were also studied to evaluate the potential role of MAO inhibition in the ICSS study. CS extract contained higher levels of several behaviorally active non-nicotine constituents (e.g., the β-carbolines norharmane and harmane) than EC extract. Nicotine alone reduced ICSS thresholds at a moderate nicotine dose, suggesting a reinforcement-enhancing effect that may promote abuse liability, and elevated ICSS thresholds at a high nicotine dose, suggesting an aversive/anhedonic effect that may limit abuse liability. CS extract elevated ICSS thresholds to a greater degree than nicotine alone at high nicotine doses. Effects of EC extract on ICSS did not differ from those of nicotine alone. Finally, CS extract significantly inhibited MAO-A and MAO-B activity in vitro, whereas EC extract and nicotine alone did not. None of the formulations inhibited MAO measured ex vivo. These findings indicate greater acute aversive/anhedonic effects for CS extract compared to nicotine alone, suggesting lower abuse liability. Although confirmation of our findings using other dosing regimens, preclinical addiction models, and tobacco product extracts is needed, these findings suggest that the centrally-mediated effects of MAO inhibitors and other non-nicotine constituents may not account for the greater abuse liability of cigarettes compared to non-combusted products. Nonetheless, identifying the specific constituent(s) mediating the effects of CS extracts in this study could help clarify mechanisms mediating tobacco addiction and inform FDA product standards.
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Affiliation(s)
- Andrew C. Harris
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States,Department of Medicine, University of Minnesota, Minneapolis, MN, United States,Department of Psychology, University of Minnesota, Minneapolis, MN, United States,*Correspondence: Andrew C. Harris,
| | - Peter Muelken
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
| | - Aleksandra Alcheva
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - Irina Stepanov
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States
| | - Mark G. LeSage
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States,Department of Medicine, University of Minnesota, Minneapolis, MN, United States,Department of Psychology, University of Minnesota, Minneapolis, MN, United States
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Berlowitz I, Egger K, Cumming P. Monoamine Oxidase Inhibition by Plant-Derived β-Carbolines; Implications for the Psychopharmacology of Tobacco and Ayahuasca. Front Pharmacol 2022; 13:886408. [PMID: 35600851 PMCID: PMC9121195 DOI: 10.3389/fphar.2022.886408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
The monoamine oxidases (MAOs) are flavin-containing amine oxidoreductases responsible for metabolism of many biogenic amine molecules in the brain and peripheral tissues. Whereas serotonin is the preferred substrate of MAO-A, phenylethylamine is metabolized by MAO-B, and dopamine and tyramine are nearly ambivalent with respect to the two isozymes. β-Carboline alkaloids such as harmine, harman(e), and norharman(e) are MAO inhibitors present in many plant materials, including foodstuffs, medicinal plants, and intoxicants, notably in tobacco (Nicotiana spp.) and in Banisteriopsis caapi, a vine used in the Amazonian ayahuasca brew. The β-carbolines present in B. caapi may have effects on neurogenesis and intrinsic antidepressant properties, in addition to potentiating the bioavailability of the hallucinogen N,N-dimethyltryptamine (DMT), which is often present in admixture plants of ayahuasca such as Psychotria viridis. Tobacco also contains physiologically relevant concentrations of β-carbolines, which potentially contribute to its psychopharmacology. However, in both cases, the threshold of MAO inhibition sufficient to interact with biogenic amine neurotransmission remains to be established. An important class of antidepressant medications provoke a complete and irreversible inhibition of MAO-A/B, and such complete inhibition is almost unattainable with reversible and competitive inhibitors such as β-carbolines. However, the preclinical and clinical observations with synthetic MAO inhibitors present a background for obtaining a better understanding of the polypharmacologies of tobacco and ayahuasca. Furthermore, MAO inhibitors of diverse structures are present in a wide variety of medicinal plants, but their pharmacological relevance in many instances remains to be established.
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Affiliation(s)
- Ilana Berlowitz
- Department of Nuclear Medicine, Inselspital Bern University Hospital, University of Bern, Bern, Switzerland
- *Correspondence: Ilana Berlowitz,
| | - Klemens Egger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Paul Cumming
- Department of Nuclear Medicine, Inselspital Bern University Hospital, University of Bern, Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane, QLD, Australia
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Taylor MR, Carrasco K, Carrasco A, Basu A. Tobacco and ADHD: A Role of MAO-Inhibition in Nicotine Dependence and Alleviation of ADHD Symptoms. Front Neurosci 2022; 16:845646. [PMID: 35495050 PMCID: PMC9039335 DOI: 10.3389/fnins.2022.845646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/21/2022] [Indexed: 11/13/2022] Open
Abstract
Attention-deficit/hyperactivity disorder (ADHD) is a relatively commonly occurring neurodevelopmental disorder affecting approximately 5% of children and young people. The neurobiological mechanisms of ADHD are proposed to particularly center around increased dopamine receptor availability related to associated symptoms of reduced attention regulation and impulsivity. ADHD is also persistent across the lifespan and associated with a raft of impulsive and health-risk behaviors including substance abuse and smoking. Research highlighting the potentially significant levels of monoamine oxidase (MAO) inhibitory properties in tobacco smoke and e-cigarettes may provide a mechanism for increased tobacco smoke dependence among those with ADHD, in addition to the role of nicotine.AimThis scoping review aimed to establish evidence for the above neurobiological pathway between smoking and ADHD symptom-alleviation or “self-medication” with the inclusion of the mechanism of MAO-inhibitors indirect increasing dopamine in the brain.MethodologyScoping review methodologies were employed in this review selected to synthesize multiple sources of empirical research to identify current gaps in the knowledge base and identify key characteristics of research data related to a phenomenon. Databases searched included OVID MEDLINE(R), Embase, Cochrane, PsycINFO and SCOPUS limited to 2000 onward and empirically validated, peer-reviewed research.FindingsThere is support for the role of MAO-inhibition on greater reinforcement of smoking for individuals with ADHD through a greater impact on dopaminergic availability than nicotine; potentially moderating ADHD symptoms.ConclusionGreater support for a “self-medication” model of ADHD and smoking includes not only nicotine but also MAO-inhibitors as dopamine agonists contained in cigarettes and e-cigarettes.
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Affiliation(s)
- Mairin Rose Taylor
- School of Health Sciences, University of Canterbury, Christchurch, New Zealand
- *Correspondence: Mairin Rose Taylor,
| | - Kelly Carrasco
- School of Education, Victoria University of Wellington, Wellington, New Zealand
| | - Andres Carrasco
- School of Health Sciences, Massey University, Wellington, New Zealand
| | - Arindam Basu
- School of Health Sciences, University of Canterbury, Christchurch, New Zealand
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Page MK, Goniewicz ML. New Analytical Method for Quantifying Flavoring Chemicals of Potential Respiratory Health Risk Concerns in e-Cigarette Liquids. Front Chem 2021; 9:763940. [PMID: 34778213 PMCID: PMC8581464 DOI: 10.3389/fchem.2021.763940] [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: 08/24/2021] [Accepted: 10/11/2021] [Indexed: 11/29/2022] Open
Abstract
Numerous flavoring chemicals are added to e-cigarette liquids to create various flavors. Flavorings provide sensory experience to users and increase product appeal; however, concerns have been raised about their potential inhalation toxicity. Estimating potential health risk of inhaling these chemicals has been challenging since little is known about their actual concentrations in e-cigarette products. To date, a limited number of analytical methods exist to measure the concentrations of flavoring chemicals in e-cigarette products. We have developed an analytical method that accurately and precisely measures the concentrations of 20 flavoring chemicals of potential inhalation risk concerns: 2,3,5-trimethylpyrazine, acetoin, benzaldehyde, benzyl alcohol, butanoic acid, dl-limonene, ethyl maltol, ethyl salicylate, ethyl vanillin, eucalyptol, eugenol, furaneol, isovanillin, l-menthol, maltol, methyl salicylate, pulegone, trans-cinnamaldehyde, triacetin, and vanillin. Calibration and QC solutions were prepared in 50:50 propylene glycol (PG):vegetable glycerin (VG) and 5% H2O and flavoring concentrations ranging from 0.02 to 10.00 mg/ml. Samples of commercial e-cigarette liquids, calibration and QC solutions were combined with 30 µL of an internal standard mix (benzene-d6, pyridine-d5, chlorobenzene-d5, naphthalene-d8 and acenaphthene-d10; 1 mg/ml each) and were diluted 100-fold into methanol. Analysis was performed on an Agilent 7890B/7250 GC/Q-TOF using a DB-624UI column (30 m x 0.25 mmID x 1.4 μm film thickness), with a total runtime of 13.5 min. Calibration curves were fit using a weighted quadratic model and correlations of determination (r2) values exceeded 0.990 for all chemicals. Bias and precision tests yielded values less than 20% and lower limits of quantitation (LLOQ) ranged from 0.02 to 0.63 mg/ml. Over 200 commercially available products, purchased or collected from adult e-cigarette users and spanning a range of flavor categories, were evaluated with this method. Concentrations of pulegone, a suspected carcinogen, varied from below limit of quantitation (BLOQ) to 0.32 mg/ml, while acetoin and vanillin, known precursors to more cytotoxic byproducts, ranged from BLOQ to 1.52 mg/ml and from BLOQ to 16.22 mg/ml, respectively. This method features a wide dynamic working range and allows for a rapid routine analysis of flavoring additives in commercial e-cigarette liquids.
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Affiliation(s)
- Michelle K Page
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
| | - Maciej L Goniewicz
- Department of Health Behavior, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
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Staal Y, Havermans A, van Nierop L, Visser W, Wijnhoven S, Bil W, Talhout R. Conceptual model for the evaluation of attractiveness, addictiveness and toxicity of tobacco and related products: The example of JUUL e-cigarettes. Regul Toxicol Pharmacol 2021; 127:105077. [PMID: 34748878 DOI: 10.1016/j.yrtph.2021.105077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 09/06/2021] [Accepted: 11/02/2021] [Indexed: 11/21/2022]
Abstract
Many new tobacco and related products (nTRP) have emerged on the market, with unknown health risks. Here, we present a conceptual model containing the factors and relations between them that contribute to the nTRP's health effects. Factors that determine attractiveness, addictiveness and toxicity of nTRP were defined based on previous assessments, literature, and expert discussions. Our model will aid in identifying key risk factors contributing to increased risk of adverse health effects for a product in a qualitative manner. Additionally, it can gauge attractiveness for specific user groups, as a determinant for population prevalence of use. Our model can be used to identify aspects of nTRP that require attention for public information or product regulation. As an example, we applied this to JUUL, a popular e-cigarette in the US. Aspects of concern for JUUL are its attractive and discrete shape, user-friendly prefilled pods, flavors, high aerosol nicotine levels, and liquids containing nicotine salts instead of free-based nicotine. The addictiveness and especially attractiveness are sufficiently high to have a large potential impact on population health due to its contribution to use and hence exposure. Products and their use can change over time; therefore market research and monitoring are crucial.
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Stefaniak AB, LeBouf RF, Ranpara AC, Leonard SS. Toxicology of flavoring- and cannabis-containing e-liquids used in electronic delivery systems. Pharmacol Ther 2021; 224:107838. [PMID: 33746051 DOI: 10.1016/j.pharmthera.2021.107838] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/11/2021] [Indexed: 12/15/2022]
Abstract
Electronic cigarettes (e-cigarettes) were introduced in the United States in 2007 and by 2014 they were the most popular tobacco product amongst youth and had overtaken use of regular tobacco cigarettes. E-cigarettes are used to aerosolize a liquid (e-liquid) that the user inhales. Flavorings in e-liquids is a primary reason for youth to initiate use of e-cigarettes. Evidence is growing in the scientific literature that inhalation of some flavorings is not without risk of harm. In this review, 67 original articles (primarily cellular in vitro) on the toxicity of flavored e-liquids were identified in the PubMed and Scopus databases and evaluated critically. At least 65 individual flavoring ingredients in e-liquids or aerosols from e-cigarettes induced toxicity in the respiratory tract, cardiovascular and circulatory systems, skeletal system, and skin. Cinnamaldehyde was most frequently reported to be cytotoxic, followed by vanillin, menthol, ethyl maltol, ethyl vanillin, benzaldehyde and linalool. Additionally, modern e-cigarettes can be modified to aerosolize cannabis as dried plant material or a concentrated extract. The U.S. experienced an outbreak of lung injuries, termed e-cigarette, or vaping, product use-associated lung injury (EVALI) that began in 2019; among 2,022 hospitalized patients who had data on substance use (as of January 14, 2020), 82% reported using a delta-9-tetrahydrocannabinol (main psychoactive component in cannabis) containing e-cigarette, or vaping, product. Our literature search identified 33 articles related to EVALI. Vitamin E acetate, a diluent and thickening agent in cannabis-based products, was strongly linked to the EVALI outbreak in epidemiologic and laboratory studies; however, e-liquid chemistry is highly complex, and more than one mechanism of lung injury, ingredient, or thermal breakdown product may be responsible for toxicity. More research is needed, particularly with regard to e-cigarettes (generation, power settings, etc.), e-liquids (composition, bulk or vaped form), modeled systems (cell type, culture type, and dosimetry metrics), biological monitoring, secondhand exposures and contact with residues that contain nicotine and flavorings, and causative agents and mechanisms of EVALI toxicity.
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Szafran BN, Pinkston R, Perveen Z, Ross MK, Morgan T, Paulsen DB, Penn AL, Kaplan BLF, Noël A. Electronic-Cigarette Vehicles and Flavoring Affect Lung Function and Immune Responses in a Murine Model. Int J Mol Sci 2020; 21:ijms21176022. [PMID: 32825651 PMCID: PMC7504509 DOI: 10.3390/ijms21176022] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/15/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022] Open
Abstract
The use of electronic nicotine delivery systems (ENDS), also known as electronic-cigarettes (e-cigs), has raised serious public health concerns, especially in light of the 2019 outbreak of e-cig or vaping product use-associated acute lung injury (EVALI). While these cases have mostly been linked to ENDS that contain vitamin E acetate, there is limited research that has focused on the chronic pulmonary effects of the delivery vehicles (i.e., without nicotine and flavoring). Thus, we investigated lung function and immune responses in a mouse model following exposure to the nearly ubiquitous e-cig delivery vehicles, vegetable glycerin (VG) and propylene glycol (PG), used with a specific 70%/30% ratio, with or without vanilla flavoring. We hypothesized that mice exposed sub-acutely to these e-cig aerosols would exhibit lung inflammation and altered lung function. Adult female C57BL/6 mice (n = 11–12 per group) were exposed to filtered air, 70%/30% VG/PG, or 70%/30% VG/PG with a French vanilla flavoring for 2 h a day for 6 weeks. Prior to sacrifice, lung function was assessed. At sacrifice, broncho-alveolar lavage fluid and lung tissue were collected for lipid mediator analysis, flow cytometry, histopathology, and gene expression analyses. Exposures to VG/PG + vanilla e-cig aerosol increased lung tidal and minute volumes and tissue damping. Immunophenotyping of lung immune cells revealed an increased number of dendritic cells, CD4+ T cells, and CD19+ B cells in the VG/PG-exposed group compared to air, irrespective of the presence of vanilla flavoring. Quantification of bioactive lung lipids demonstrated a >3-fold increase of 2-arachidonoylglycerol (2-AG), an anti-inflammatory mediator, and a 2-fold increase of 12-hydroxyeicosatetraenoic acid (12-HETE), another inflammatory mediator, following VG/PG exposure, with or without vanilla flavoring. This suggests that e-cig aerosol vehicles may affect immunoregulatory molecules. We also found that the two e-cig aerosols dysregulated the expression of lung genes. Ingenuity Pathway Analysis revealed that the gene networks that are dysregulated by the VG/PG e-cig aerosol are associated with metabolism of cellular proteins and lipids. Overall, our findings demonstrate that VG and PG, the main constituents of e-liquid formulations, when aerosolized through an e-cig device, are not harmless to the lungs, since they disrupt immune homeostasis.
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Affiliation(s)
- Brittany N. Szafran
- Center for Environmental Health Sciences, Department of Basic Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS 39762, USA; (B.N.S.); (M.K.R.); (B.L.F.K.)
| | - Rakeysha Pinkston
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA; (R.P.); (Z.P.); (A.L.P.)
- Department of Environmental Toxicology, Southern University, Baton Rouge, LA 70803, USA
| | - Zakia Perveen
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA; (R.P.); (Z.P.); (A.L.P.)
| | - Matthew K. Ross
- Center for Environmental Health Sciences, Department of Basic Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS 39762, USA; (B.N.S.); (M.K.R.); (B.L.F.K.)
| | - Timothy Morgan
- Department of Pathobiology and Population Medicine, Mississippi State University College of Veterinary Medicine, Mississippi State, MS 39762, USA;
| | - Daniel B. Paulsen
- Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA;
| | - Arthur L. Penn
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA; (R.P.); (Z.P.); (A.L.P.)
| | - Barbara L. F. Kaplan
- Center for Environmental Health Sciences, Department of Basic Sciences, Mississippi State University College of Veterinary Medicine, Mississippi State, MS 39762, USA; (B.N.S.); (M.K.R.); (B.L.F.K.)
| | - Alexandra Noël
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA; (R.P.); (Z.P.); (A.L.P.)
- Correspondence: ; Tel.: +1-225-578-9753
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Patten T, De Biasi M. History repeats itself: Role of characterizing flavors on nicotine use and abuse. Neuropharmacology 2020; 177:108162. [PMID: 32497589 DOI: 10.1016/j.neuropharm.2020.108162] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [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: 03/13/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 12/13/2022]
Abstract
The popularity of e-cigarettes has skyrocketed in recent years, and most vapers use flavored e-cigarette products. Consumption of flavored e-cigarettes exceeds that of combustible cigarettes and other tobacco products among adolescents, who are particularly vulnerable to becoming nicotine dependent. Flavorings have been used by the tobacco industry since the 17th century, but the use of flavors by the e-cigarette industry to create products with "characterizing" flavors (i.e. flavors other than tobacco or menthol) has sparked a public health debate. This review addresses the possibility that characterizing flavors make nicotine more appealing, rewarding and addictive. It also discusses ways in which preclinical and clinical studies could improve our understanding of the mechanisms by which flavors may alter nicotine reward and reinforcement. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Theresa Patten
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Mariella De Biasi
- Pharmacology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
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