In vitro toxicological evaluation of aerosols generated by a 4th generation vaping device using nicotine salts in an air-liquid interface system.

BACKGROUND: Electronic cigarettes (EC) have gained popularity, especially among young people, with the introduction of fourth-generation devices based on e-liquids containing nicotine salts that promise a smoother vaping experience than freebase nicotine. However, the toxicological effects of nicotine salts are still largely unknown, and the chemical diversity of e-liquids limits the comparison between different studies to determine the contribution of each compound to the cytotoxicity of EC aerosols. Therefore, the aim of this study was to evaluate the toxicological profile of controlled composition e-liquid aerosols to accurately determine the effects of each ingredient based on exposure at the air-liquid interface. METHODS: Human lung epithelial cells (A549) were exposed to undiluted aerosols of controlled composition e-liquids containing various ratios of propylene glycol (PG)/vegetable glycerin (VG) solvents, freebase nicotine, organic acids, nicotine salts, and flavoured commercial e-liquids. Exposure of 20 puffs was performed at the air-liquid interface following a standard vaping regimen. Toxicological outcomes, including cytotoxicity, inflammation, and oxidative stress, were assessed 24 h after exposure. RESULTS: PG/VG aerosols elicited a strong cytotoxic response characterised by a 50% decrease in cell viability and a 200% increase in lactate dehydrogenase (LDH) production, but had no effects on inflammation and oxidative stress. These effects occurred only at a ratio of 70/30 PG/VG, suggesting that PG is the major contributor to aerosol cytotoxicity. Both freebase nicotine and organic acids had no greater effect on cell viability and LDH release than at a 70/30 PG/VG ratio, but significantly increased inflammation and oxidative stress. Interestingly, the protonated form of nicotine in salt showed a stronger proinflammatory effect than the freebase nicotine form, while benzoic acid-based nicotine salts also induced significant oxidative stress. Flavoured commercial e-liquids was found to be cytotoxic at a threshold dose of ≈ 330 µg/cm². CONCLUSION: Our results showed that aerosols of e-liquids consisting only of PG/VG solvents can cause severe cytotoxicity depending on the concentration of PG, while nicotine salts elicit a stronger pro-inflammatory response than freebase nicotine. Overall, aerosols from fourth-generation devices can cause different toxicological effects, the nature of which depends on the chemical composition of the e-liquid.

Alcohol and e-cigarette damage alveolar-epithelial barrier by activation of P2X7r and provoke brain endothelial injury via extracellular vesicles.

BACKGROUND: Use of nicotine containing products like electronic cigarettes (e-Cig) and alcohol are associated with mitochondrial membrane depolarization, resulting in the extracellular release of ATP, and mitochondrial DNA (mtDNA), mediating inflammatory responses. While nicotine effects on lungs is well-known, chronic alcohol (ETH) exposure also weakens lung immune responses and cause inflammation. Extracellular ATP (eATP) released by inflammatory/stressed cells stimulate purinergic P2X7 receptors (P2X7r) activation in adjacent cells. We hypothesized that injury caused by alcohol and e-Cig to pulmonary alveolar epithelial cells (hPAEpiC) promote the release of eATP, mtDNA and P2X7r in circulation. This induces a paracrine signaling communication either directly or via EVs to affect brain cells (human brain endothelial cells - hBMVEC). METHODS: We used a model of primary human pulmonary alveolar epithelial cells (hPAEpiC) and exposed the cells to 100 mM ethanol (ETH), 100 µM acetaldehyde (ALD), or e-Cig (1.75 µg/mL of 1.8% or 0% nicotine) conditioned media, and measured the mitochondrial efficiency using Agilent Seahorse machine. Gene expression was measured by Taqman RT-qPCR and digital PCR. hPAEpiC-EVs were extracted from culture supernatant and characterized by flow cytometric analysis. Calcium (Ca2+) and eATP levels were quantified using commercial kits. To study intercellular communication via paracrine signaling or by EVs, we stimulated hBMVECs with hPAEpiC cell culture medium conditioned with ETH, ALD or e-cig or hPAEpiC-EVs and measured Ca2+ levels. RESULTS: ETH, ALD, or e-Cig (1.8% nicotine) stimulation depleted the mitochondrial spare respiration capacity in hPAEpiC. We observed increased expression of P2X7r and TRPV1 genes (3-6-fold) and increased intracellular Ca2+ accumulation (20-30-fold increase) in hPAEpiC, resulting in greater expression of endoplasmic reticulum (ER) stress markers. hPAEpiC stimulated by ETH, ALD, and e-Cig conditioned media shed more EVs with larger particle sizes, carrying higher amounts of eATP and mtDNA. ETH, ALD and e-Cig (1.8% nicotine) exposure also increased the P2X7r shedding in media and via EVs. hPAEpiC-EVs carrying P2X7r and eATP cargo triggered paracrine signaling in human brain microvascular endothelial cells (BMVECs) and increased Ca2+ levels. P2X7r inhibition by A804598 compound normalized mitochondrial spare respiration, reduced ER stress and diminished EV release, thus protecting the BBB function. CONCLUSION: Abusive drugs like ETH and e-Cig promote mitochondrial and endoplasmic reticulum stress in hPAEpiC and disrupts the cell functions via P2X7 receptor signaling. EVs released by lung epithelial cells against ETH/e-cig insults, carry a cargo of secondary messengers that stimulate brain cells via paracrine signals.

Do Flavour Descriptions Influence Subjective Ratings of Flavoured and Unflavoured E-Liquids among Non-Smoking and Non-Vaping UK Adolescents?

INTRODUCTION: Youth use of electronic cigarettes (e-cigarettes) is rising globally and is associated with health harms. Flavour descriptions on e-liquid packaging may contribute to the appeal of e-cigarettes among youth. This study compared subjective ratings of e-liquid packaging flavour descriptions among non-smoking and non-vaping UK adolescents. METHODS: This was an online observational study in a UK sample of non-smoking and non-vaping adolescents aged 11-17 years. The primary analyses compared flavoured versus unflavoured descriptions and the secondary analyses compared candy/sweet flavour versus fruit flavour descriptions. Outcomes were packaging appraisal, packaging receptivity, perceived harm, and perceived audience. RESULTS: The survey was completed by 120 participants (74% female). Packaging appraisal ratings were higher for e-liquids with flavoured descriptions than unflavoured descriptions (mean difference 5.9, 95% CI 4.2 to 7.6, p<.001). Similarly, packaging receptivity ratings were higher for e-liquids with flavoured descriptions than unflavoured descriptions (mean difference 4.2, 95% CI 2.8 to 5.6, p<.001). Participants also perceived e-liquids with flavoured (versus unflavoured) descriptions as less 'grown-up' (mean difference -5.2, 95% CI -7.3 to -3.1, p<.001). However, ratings of perceived harm were similar for flavoured and unflavoured descriptions (mean difference -1.0, 95% CI -2.6 to 0.5, p=.189). CONCLUSIONS: Although this study found differences in subjective ratings of e-liquids with flavoured and unflavoured descriptions, non-smoking and non-vaping UK adolescents generally had low appraisal and receptivity for e-liquids and they perceived them as being 'grown-up' and harmful. IMPLICATIONS: Youth use of electronic cigarettes (e-cigarettes) is increasing globally, leading to concerns about health harms. This study compared adolescents' ratings of e-liquids with flavoured versus unflavoured descriptions and e-liquids with candy/sweet flavour versus fruit flavour descriptions. This study adds to previous studies that have compared adolescents' ratings of e-liquids with tobacco flavour versus non-tobacco flavour descriptions. Although packaging appraisal and receptivity ratings were higher (more positive) for e-liquids with flavoured versus unflavoured descriptions, overall, adolescents who do not smoke or vape had low appraisal and receptivity for e-liquids, and they perceived them as being 'grown-up' and harmful.

Reliable biological indicator identification and evaluation of tobacco-derived nicotine using an ultra-sensitive gas chromatography-tandem mass spectrometric method.

Several countries have exempted synthetic nicotine from existing regulatory frameworks, resulting in the widespread substitution of synthetic nicotine (SN) in almost all e-cigarette products available. However, it remains uncertain whether the purported synthetic nicotine is indeed genuine SN. There is a need to develop biological indicators and an analytical method that more clearly distinguishes between the two sources. Impurities in neat tobacco-derived nicotine (TDN) were characterized and identified through non-targeted and targeted analysis. Gas chromatography-tandem mass spectrometry (GC-MS/MS) conditions were optimized for detecting biological indicators in e-cigarette products. Nine tobacco-related alkaloids were identified and selected as biological indicators for TDN. A liquid-liquid extraction and GC-MS/MS quantitative method were developed to detect nine biological indicators in e-cigarette products with the limit of quantification ranging from 0.2 to 4.2 µg L-1 using 0.5 mL of e-liquid. This method was applied to 50 e-cigarette brands purchased in the Korean market. The developed method was able to easily and accurately identify the origin of nicotine even using a small amount of e-liquid sample. It is expected that effective e-cigarette regulation will be possible if the nicotine biological indicator and high-sensitivity analysis method developed in this study are used.

Insomnia and parasomnia induced by validated smoking cessation pharmacotherapies and electronic cigarettes: a network meta-analysis.

We aim to assess the relationship between validated smoking cessation pharmacotherapies and electronic cigarettes (e-cigarettes) and insomnia and parasomnia using a systematic review and a network meta-analysis. A systematic search was performed until August 2022 in the following databases: PUBMED, COCHRANE, CLINICALTRIAL. Randomized controlled studies against placebo or validated therapeutic smoking cessation methods and e-cigarettes in adult smokers without unstable or psychiatric comorbidity were included. The primary outcome was the presence of "insomnia" and "parasomnia." A total of 1261 studies were selected. Thirty-seven studies were included in the quantitative analysis (34 for insomnia and 23 for parasomnia). The reported interventions were varenicline (23 studies), nicotine replacement therapy (NRT, 10 studies), bupropion (15 studies). No studies on e-cigarettes were included. Bayesian analyses found that insomnia and parasomnia are more frequent with smoking cessation therapies than placebo except for bupropion. Insomnia was less frequent with nicotine substitutes but more frequent with bupropion than the over pharmacotherapies. Parasomnia are less frequent with bupropion but more frequent with varenicline than the over pharmacotherapies. Validated smoking cessation pharmacotherapies can induce sleep disturbances with different degrees of frequency. Our network meta-analysis shows a more favorable profile of nicotine substitutes for insomnia and bupropion for parasomnia. It seems essential to systematize the assessment of sleep disturbances in the initiation of smoking cessation treatment. This could help professionals to personalize the choice of treatment according to sleep parameters of each patient. Considering co-addictions, broadening the populations studied and standardizing the measurement are additional avenues for future research.

Time-Varying Determinants of Changes in E-Cigarette Relative Harm Perception Among US Young Adults.

BACKGROUND: Current e-cigarette use has increased among young adults in the USA despite a consistent decrease in perceiving e-cigarettes as less harmful than cigarettes over time. This study examined time-varying predictors associated with the changes in e-cigarette relative harm perception over time among US young adults. METHODS: Data were from the 2013-2018 Population Assessment of Tobacco and Health (PATH) Study for young adults (18-24 years). A time-varying effect model (TVEM) was applied to examine the association between the relative harm perception change and the associated time-varying predictors. RESULTS: Of the 8427 young adults, the prevalence of those who perceived e-cigarettes as less harmful than cigarettes decreased from 50.3% in Wave 1 (2013-2014) to 27.7% in Wave 4 (2016-2018). Young adults who were male were more likely to perceive e-cigarettes as less harmful than cigarettes over time (OR = 1.58; 95%CI, 1.53-1.64). In addition, the changes in e-cigarette relative harm perception were less noticeable among those with advanced degrees, who had non-combustible smoke-free home rules, who held negative tobacco-related attitudes, and those who were current e-cigarette users or ever used alcohol (all p values < 0.05). CONCLUSIONS: A decline was observed in US young adults who perceived e-cigarettes as less harmful than cigarettes from the PATH Study across four waves (2013-2018). The study findings underscore the importance of risk communication that focuses on harm perception profiles and the need for appropriate interventions to balance the considerations of e-cigarette use among young adults.

Cytotoxic impact of nicotine products on periodontal ligament cells.

OBJECTIVES: The primary objective of this in vitro experiment was an assessment of proliferative capacity, metabolic activity, and potential cellular detriment of human periodontal ligament cells (hPDL) exposed to cigarette smoke (CS), electronic cigarette vapor (eCV), and heated tobacco product aerosol (HTP), or air (control). MATERIALS AND METHODS: Using a CAD/CAM-designed exposition chamber, hPDL were exposed to CS, eCV, HTP, or air (control) based on the Health Canada Intense Smoking Regime. Cell proliferation, metabolic activity, and cellular detriment were assessed at various time points. RESULTS: Compared to the control, hPDL exposed to CS exhibited significantly decreased cell numbers at all time points. HTP exposure led to reduced cell numbers 48 h and 72 h post-exposure, while eCV-exposed cells showed no significant decrease. The metabolic activity of eCV-treated hPDL was slightly reduced at 7 h but recovered at 24 h and 48 h. In contrast, CS-treated cells exhibited significantly decreased metabolic activity at 24 h and 48 h, and HTP-exposed cells showed a significant decrease after 48 h. Flow cytometry indicated both apoptotic and necrotic cell death following CS exposure, with necrotic cell death being more pronounced. CONCLUSIONS: eCV and HTP demonstrated comparatively reduced detrimental effects on hPDL compared to CS. CLINICAL RELEVANCE: The findings suggest that conventional cigarette smoke poses a substantial risk to periodontal health by significantly impairing cell proliferation and metabolic activity. However, alternatives such as eCV and HTP may offer a comparatively reduced risk.

The Role of the School Nurse in E-Cigarette Prevention and Cessation: A Scoping Review.

E-cigarettes have rapidly gained popularity among youth in recent years. This scoping review identifies opportunities for school nurses to incorporate e-cigarette prevention strategies into their practice and identifies gaps for future research in school nursing evidence-based practice. Using the methodological framework developed by Arksey and O'Malley and advanced by Levac et al., a literature review was conducted using PubMed, Cumulative Index to Nursing and Allied Health (CINAHL), and Education Resources Information Center (ERIC) databases. A total of 15 articles were included in the final review. Articles for inclusion addressed interventions aimed at reducing e-cigarette use in K-12 schools. The results highlight two general types of school-based interventions: (1) universal e-cigarette prevention education and (2) targeted e-cigarette use-cessation programs. Each of these types of interventions presents a leadership opportunity for school nurses to engage within all domains of their scope of practice.

Assessing acute nicotine impact on choroidal thickness: a randomized, double-blinded study comparing smoking cessation aids, including nicotine gum and electronic cigarettes.

PURPOSE: To explore whether differences in choroidal thickness arise from nicotine consumption in healthy young individuals, specifically comparing the effects of nicotine gum to electronic cigarette (vaping), while maintaining a consistent 4 mg nicotine dosage. METHODS: In a randomized double-blinded prospective cross-sectional study, 20 healthy participants (mean age ± standard deviation: 23 ± 2.36 years) were randomly assigned to either the nicotine gum or vaping group. Choroidal thickness (ChT) measurements were conducted using optical coherence tomography (OCT) (Topcon 3D OCT-1 Maestro System) at baseline, 30, and 60 min after ingesting 4 mg of nicotine, with ChT measurements taken from five different horizontal areas. RESULTS: Neither the nicotine delivery method (gum or vaping) demonstrated a statistically significant impact on ChT mean scores among subjects in the five measured areas at baseline, 30, and 60 min (p > 0.05). However, significant differences were observed in ChT mean scores within subjects across the five areas (F (1.83, 72) = 36.43, p < 0.001), regardless of other study factors such as group, time, and visit (p > 0.05). A statistically significant interaction was identified between the factors of area and time concerning participants' ChT mean scores when stratified by the type of smoking (tobacco, vaping, and dual) (p = 0.003). CONCLUSION: The results of this study revealed that nicotine, up to particular concentration of 4 mg, does not have a statistically significant vasoconstrictive effect on choroidal thickness, regardless of the delivery method, within the examined group. These findings offer valuable insights into the relationship between nicotine intake and choroidal dynamics in young adults.

An overview of tobacco use in France: Observed trends and new challenges / État des lieux de la situation du tabagisme en France : tendances observées et nouveaux enjeux

This article reports changes in tobacco and vaping consumption in France over the last thirty years and the issues they raise for public authorities in terms of prevention and management of the social and health consequences. This report is the result of a joint analysis by Santé publique France (SpF) and the French Monitoring Center for Drugs and Drug Addiction (OFDT). It shows that there has been a "generational shift" in tobacco consumption and social representations of cigarettes since the mid-2010s, with a sharp decline in tobacco initiation among adolescents, which has become less common and reported at an older age, which was one of the objectives of the national tobacco reduction plans. However, smoking remains fairly stable among adults, predominantly among men, with gaps between men and women persisting since the early 2000s. Beyond the gender gap, social disparities in consumption remain significant, both among youth and adults. However, while the prevalence of smoking is no longer increasing, the prevalence of vaping is rising, which is a public health concern since some of these practices involve nicotine consumption. This also entails the risk of a "renormalization" of the act of smoking, a matter of concern for health authorities in France as in other European countries. The analysis concludes that the statistical information system and qualitative surveys need to be adapted to ensure a reliable monitoring of the situation, taking into account the rapid transformations of the market.

Cet article fait le point sur les évolutions en matière de consommation de tabac et de produits de vapotage, en France, depuis une trentaine d'années, et les enjeux qu'elles soulèvent pour les pouvoirs publics, en termes de prévention et de prise en charge des conséquences sociosanitaires. Produit d'une analyse conjointe de Santé publique France (SpF) et de l'Observatoire français des drogues et des tendances addictives (OFDT), il montre d'abord un « tournant générationnel ¼ dans la consommation de tabac et les représentations sociales de la cigarette depuis le milieu des années 2010, avec un recul marqué de l'expérimentation parmi les adolescents, qui est devenue à la fois moins courante et plus tardive, ce qui était un des objectifs des plans nationaux de réduction du tabagisme successivement mis en place depuis 2014. Le tabagisme reste néanmoins assez stable parmi les adultes, prédominant chez les hommes, avec des écarts entre hommes et femmes qui se maintiennent depuis le début des années 2000. Au-delà du différentiel de genre, les disparités sociales de consommation restent importantes, parmi les jeunes comme à l'âge adulte. Cependant, si la prévalence du tabagisme ne progresse plus, celle du vapotage augmente, ce qui constitue un point d'attention dès lors qu'une partie de ces pratiques induit une consommation de nicotine. Cela induit également le risque d'une « renormalisation ¼ de l'acte de fumer, qui constitue un point de vigilance des autorités sanitaires, en France comme dans d'autres pays européens. L'analyse se conclut sur la nécessité de continuer à adapter le système d'information statistique et les enquêtes qualitatives pour permettre un suivi épidémiologique de la situation qui reste performant.

Comparative study of the effects of cigarette smoke versus next-generation tobacco and nicotine product extracts on inflammatory biomarkers of human monocytes.

Monocytes exhibiting a pro-inflammatory phenotype play a key role in adhesion and development of atherosclerotic plaques. As an alternative to smoking, next-generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their pro-inflammatory effects on monocytes. We investigated cell viability, anti-oxidant and pro-inflammatory gene and protein expression in THP-1 monocytes after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine (nic). Treatment with 3R4F reduced cell viability in a dose-dependent manner, whereas exposure to alternative smoking products showed no difference to control. At the highest non-lethal dose of 3R4F (20%), the following notable mRNA expression changes were observed for 3R4F, HTP, and e-cig respectively, relative to control; HMOX1 (6-fold, < 2-fold, < 2-fold), NQO1 (3.5-fold, < 2-fold, < 2-fold), CCL2 (4-fold, 3.5-fold, 2.5-fold), IL1B (4-fold, 3-fold, < 2-fold), IL8 (5-fold, 2-fold, 2-fold), TNF (2-fold, 2-fold, < 2-fold) and ICAM1 was below the 2-fold threshold for all products. With respect to protein expression, IL1B (3-fold, < 2-fold, < 2-fold) and IL8 (3.5-fold, 2-fold, 2-fold) were elevated over the 2-fold threshold, whereas CCL2, TNF, and ICAM1 were below 2-fold expression for all products. At higher doses, greater inductions were observed with all extracts; however, NGP responses were typically lower than 3R4F. In conclusion, anti-oxidative and pro-inflammatory processes were activated by all products. NGPs overall showed lower responses relative to controls than THP-1 cells exposed to 3R4F AqE.

Electronic cigarette exposure disrupts airway epithelial barrier function and exacerbates viral infection.

The use of electronic cigarettes (e-cigs), especially among teenagers, has reached alarming and epidemic levels, posing a significant threat to public health. However, the short- and long-term effects of vaping on the airway epithelial barrier are unclear. Airway epithelial cells are the forefront protectors from viruses and pathogens. They contain apical junctional complexes (AJCs), which include tight junctions (TJs) and adherens junctions (AJs) formed between adjacent cells. Previously, we reported respiratory syncytial virus (RSV) infection, the leading cause of acute lower respiratory infection-related hospitalization in children and high-risk adults, induces a "leaky airway" by disrupting the epithelial AJC structure and function. We hypothesized chemical components of e-cigs disrupt airway epithelial barrier and exacerbate RSV-induced airway barrier dysfunction. Using confluent human bronchial epithelial (16HBE) cells and well-differentiated normal human bronchial epithelial (NHBE) cells, we found that exposure to extract and aerosol e-cig nicotine caused a significant decrease in transepithelial electrical resistance (TEER) and the structure of the AJC even at noncytotoxic concentrations. Western blot analysis of 16HBE cells exposed to e-cig nicotine extract did not reveal significant changes in AJC proteins. Exposure to aerosolized e-cig cinnamon or menthol flavors also induced barrier disruption and aggravated nicotine-induced airway barrier dysfunction. Moreover, preexposure to nicotine aerosol increased RSV infection and the severity of RSV-induced airway barrier disruption. Our findings demonstrate that e-cig exposure disrupts the airway epithelial barrier and exacerbates RSV-induced damage. Knowledge gained from this study will provide awareness of adverse e-cig respiratory effects and positively impact the mitigation of e-cig epidemic.NEW & NOTEWORTHY Electronic cigarette (e-cig) use, especially in teens, is alarming and at epidemic proportions, threatening public health. Our study shows that e-cig nicotine exposure disrupts airway epithelial tight junctions and increases RSV-induced barrier dysfunction. Furthermore, exposure to aerosolized flavors exaggerates e-cig nicotine-induced airway barrier dysfunction. Our study confirms that individual and combined components of e-cigs deleteriously impact the airway barrier and that e-cig exposure increases susceptibility to viral infection.

The mediating roles of the oral microbiome in saliva and subgingival sites between e-cigarette smoking and gingival inflammation.

BACKGROUND: Electronic cigarettes (ECs) have been widely used by young individuals in the U.S. while being considered less harmful than conventional tobacco cigarettes. However, ECs have increasingly been regarded as a health risk, producing detrimental chemicals that may cause, combined with poor oral hygiene, substantial inflammation in gingival and subgingival sites. In this paper, we first report that EC smoking significantly increases the odds of gingival inflammation. Then, through mediation analysis, we seek to identify and explain the mechanism that underlies the relationship between EC smoking and gingival inflammation via the oral microbiome. METHODS: We collected saliva and subgingival samples from 75 EC users and 75 non-users between 18 and 34 years in age and profiled their microbial compositions via 16S rRNA amplicon sequencing. We conducted raw sequence data processing, denoising and taxonomic annotations using QIIME2 based on the expanded human oral microbiome database (eHOMD). We then created functional annotations (i.e., KEGG pathways) using PICRUSt2. RESULTS: We found significant increases in α-diversity for EC users and disparities in ß-diversity between EC users and non-users. We also found significant disparities between EC users and non-users in the relative abundance of 36 microbial taxa in the saliva site and 71 microbial taxa in the subgingival site. Finally, we found that 1 microbial taxon in the saliva site and 18 microbial taxa in the subgingival site significantly mediated the effects of EC smoking on gingival inflammation. The mediators on the genus level, for example, include Actinomyces, Rothia, Neisseria, and Enterococcus in the subgingival site. In addition, we report significant disparities between EC users and non-users in the relative abundance of 71 KEGG pathways in the subgingival site. CONCLUSIONS: These findings reveal that continued EC use can further increase microbial dysbiosis that may lead to periodontal disease. Our findings also suggest that continued surveillance for the effect of ECs on the oral microbiome and its transmission to oral diseases is needed.

Electronic cigarette menthol flavoring is associated with increased inhaled micro and sub-micron particles and worse lung function in combustion cigarette smokers.

Flavored electronic cigarettes (ECs) present a serious health challenge globally. Currently, it is unknown whether the addition of highly popular menthol flavoring to e-liquid is associated with changes in the number of aerosolized particles generated or altered lung function. Here, we first performed preclinical studies using our novel robotic platform Human Vaping Mimetic Real-Time Particle Analyzer (HUMITIPAA). HUMITIPAA generates fresh aerosols for any desired EC in a very controlled and user-definable manner and utilizes an optical sensing system to quantitate and analyze sub-micron and microparticles from every puff over the course of vaping session in real-time while emulating clinically relevant breathing mechanics and vaping topography. We discovered that addition of menthol flavoring to freshly prepared e-liquid base propylene glycol-vegetable glycerin leads to enhanced particle counts in all tested size fractions, similar to the effect of adding vitamin E acetate to e-liquid we previously reported. Similarly, we found that menthol vs. non-menthol (tobacco) flavored pods from commercially available ECs leads to generation of significantly higher quantities of 1-10 µm particles upon inhalation. We then retrospectively analyzed data from the COPDGene study and identified an association between the use of menthol flavored ECs and reduced FEV1% predicted and FEV1/FVC independent of age, gender, race, pack-years of smoking, and use of nicotine or cannabis-containing vaping products. Our results reveal an association between enhanced inhaled particle due to menthol addition to ECs and worse lung function indices. Detailed causal relation remains to be demonstrated in future large-scale prospective clinical studies. Importantly, here we demonstrate utility of the HUMITIPAA as a predictive enabling technology to identify inhalation toxicological potential of emerging ECs as the chemical formulation of e-liquid gets modified.

Factors associated with smoking cessation in exclusive smokers and dual users of e-cigarette and conventional cigarettes from CDTnet registry.

Dual use of electronic cigarettes and conventional cigarettes may be a transitional state towards cigarette smoking cessation. However, maintaining dual use may increase tobacco-related consequences as smoking behavior persists. The aim of our study was to describe characteristics of dual users and explore factors associated with their one-month abstinence in comparison to exclusive smokers in French smoking cessation services (SCS). We retrospectively studied 5116 smokers registered in a national SCS registry between 2015 and 2018 and who attended at least two visits. We matched the retained exclusive smokers and dual users by age, sex, professional status and education level. We compared baseline information and validated smoking abstinence at one-month follow-up between the two groups. Predictors of abstinence were assessed using a multivariate model. Retained exclusive smokers and dual users had similar cessation rates (37%). Compared to exclusive smokers, dual users presented more comorbidities and a higher level of nicotine dependence. Factors positively associated with cessation in dual users were: being employed or retired, declaring three or more previous quit attempts, presenting with low nicotine dependence and high motivation to quit and benefiting from at least four follow-up consultations. Our results suggest that dual users seeking help to quit in SCS seem to benefit from support as much as exclusive smokers to reach abstinence, despite a higher level of nicotine dependence and comorbidities. Further research, especially qualitative, is needed on this specific group of smokers to provide tailored interventions to quit.

Adverse Biophysical Impact of e-Cigarette Flavors on Pulmonary Surfactant.

The attractiveness and abundance of flavors are primary factors eliciting youth to use e-cigarettes. Emerging studies in recent years revealed the adverse health impact of e-cigarette flavoring chemicals, including disruption of the biophysical function of pulmonary surfactants in the lung. Nevertheless, a comprehensive understanding of the biophysical impact of various flavoring chemicals is still lacking. We used constrained drop surfactometry as a new alternative method to study the biophysical impact of flavored e-cigarette aerosols on an animal-derived natural pulmonary surfactant. The dose of exposure to e-cigarette aerosols was quantified with a quartz crystal microbalance, and alterations to the ultrastructure of the surfactant film were visualized using atomic force microscopy. We have systematically studied eight representative flavoring chemicals (benzyl alcohol, menthol, maltol, ethyl maltol, vanillin, ethyl vanillin, ethyl acetate, and ethyl butyrate) and six popular recombinant flavors (coffee, vanilla, tobacco, cotton candy, menthol/mint, and chocolate). Our results suggested a flavor-dependent inhibitory effect of e-cigarette aerosols on the biophysical properties of the pulmonary surfactant. A qualitative phase diagram was proposed to predict the hazardous potential of various flavoring chemicals. These results provide novel implications in understanding the environmental, health, and safety impacts of e-cigarette aerosols and may contribute to better regulation of e-cigarette products.

Identification and Characterization of Synthetic Nicotine Product Promotion and Sales on Instagram Using Natural Language Processing.

INTRODUCTION: There has been a rapid proliferation of synthetic nicotine products in recent years, despite newly established regulatory authority and limited research into its health risks. Previous research has implicated social media platforms as an avenue for nicotine product unregulated sales. Yet, little is known about synthetic nicotine product content on social media. We utilized natural language processing to characterize the sales of synthetic nicotine products on Instagram. METHODS: We collected Instagram posts by querying Instagram hashtags (e.g., "#tobaccofreenicotine) related to synthetic nicotine. Using BERT, collected posts were categorized into thematically related topic clusters. Posts within topic clusters relevant to study aims were then manually annotated for variables related to promotion and selling (e.g., cost discussion, contact information for offline sales). RESULTS: A total of 7,425 unique posts were collected with 2,219 posts identified as related to promotion and selling of synthetic nicotine products. Nicotine pouches (52.9%, n=1174), ENDS (30.6%, n=679), and flavored e-liquids (14.1%, n=313) were most commonly promoted. 16.1% (n=345) of posts contained embedded hyperlinks and 5.8% (n=129) provided contact information for purported offline transactions. Only 17.6% (n=391) of posts contained synthetic nicotine specific health warnings. CONCLUSIONS: In the United States, synthetic nicotine products can only be legally marketed if they have received premarket authorization from the FDA. Despite these prohibitions, Instagram appears to be a hub for potentially unregulated sales of synthetic and "tobacco-free" products. Efforts are needed by platforms and regulators to enhance content moderation and prevent unregulated online sales of existing and emerging synthetic nicotine products. IMPLICATIONS: There is limited clinical understanding of synthetic nicotine's unique health risks and how these novel products are changing over time due to regulatory oversight. Despite synthetic nicotine specific regulatory measures, such as the requirement for premarket authorization and FDA warning letters issued to unauthorized sellers, access to and promotion of synthetic nicotine is widely occurring on Instagram, a platform with over 2 billion users and one that is popular among youth and young adults. Activities include direct-to-consumer sales from questionable sources, inadequate health warning disclosure, and exposure with limited age restrictions, all conditions necessary for the sale of various tobacco products. Notably, the number of these Instagram posts increased in response to the announcement of new FDA regulations. In response, more robust online monitoring, content moderation, and proactive enforcement is needed from platforms who should work collaboratively with regulators to identify, report, and remove content in clear violation of platform policies and federal laws. Regulatory implementation and enforcement should prioritize digital platforms as conduits for unregulated access to synthetic nicotine products and other future novel and emerging tobacco products.

Oral epithelium response of electronic cigarette users to electronic cigarette.

BACKGROUND: Electronic cigarettes are increasing in popularity, but there is only little information on their biologic effects on the oral epithelium, the initial site exposed to electronic cigarette smoke. METHODS: We assessed the oral epithelium response to electronic cigarettes by comparing the histology and RNA transcriptome (mRNA and miRNA) of healthy electronic cigarette vapers to nonsmokers. mRNA was assessed based on: (1) genome-wide; (2) genes previously identified as dysregulated in the oral epithelium of electronic cigarette vapers versus nonsmokers; (3) immune and inflammatory-related genes previously identified as dysregulated in the nasal epithelium of electronic cigarette vapers compared to nonsmokers; (4) genes previously identified as dysregulated in the small airway epithelium of nonsmokers following an acute exposure to electronic cigarette; and (5) genes related to the initial steps of COVID-19 infection. In addition, miRNA was assessed genome-wide. Comparisons were performed using analysis of variance, and Benajmini-Hochberg corrected p < 0.05 was considered significant. RESULTS: The histology of the epithelium, lamina propria and basal layer in electronic cigarette vapers appeared normal. Assessment of mRNA and miRNA, based on all gene lists, did not identify any genes significantly modified in the oral epithelium of electronic cigarette vapers in response to electronic cigarette use. CONCLUSION: An average history of 2 years of vaping results in no detectable histologic or transcriptome abnormalities in the buccal mucosa.

Passive exposure to electronic cigarette aerosol in pregnancy: A case study of a family.

BACKGROUND: Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member. METHODS: This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period. RESULTS: Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old. CONCLUSIONS: We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

Oral microbiome of electronic cigarette users: A cross-sectional exploration.

OBJECTIVE: Electronic cigarettes have increased in popularity globally. Vaping may be associated with oral symptoms and pathologies including dental and periodontal damage, both of which have an underlying microbial etiology. The primary aim of this pilot study, therefore, was to compare the oral microbiome of vapers and non-vapers. SUBJECTS AND METHODS: This secondary data analysis had a cross-sectional comparative descriptive design and included data for 36 adults. Bacterial 16S rRNA genes were extracted and amplified from soft tissue oral swab specimens and taxonomically classified using the Human Oral Microbiome Database. RESULTS: Data for 18 vapers and 18 non-vapers were included in this study. Almost 56% of the vapers also smoked conventional cigarettes. Beta diversity differences were identified between vapers and non-vapers. Vapers had a significantly higher relative abundance of an unclassified species of Veillonella compared with non-vapers. Dual users had higher alpha diversity compared with exclusive vapers. Beta diversity was also associated with dual use. Multiple OTUs were identified to be associated with dual use of e-cigarettes and conventional cigarettes. CONCLUSIONS: Vapers exhibit an altered oral microbiome. Dual use of electronic cigarettes and conventional cigarettes is associated with the presence of several known pathogenic microbes.