A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

Systemic biomarkers in electronic cigarette users: implications for noninvasive assessment of vaping-associated pulmonary injuries

Background

Electronic cigarettes (e-cigs) were introduced as electronic nicotine delivery systems, and have become very popular in the USA and globally. There is a paucity of data on systemic injury biomarkers of vaping in e-cig users that can be used as a noninvasive assessment of vaping-associated lung injuries. We hypothesised that characterisation of systemic biomarkers of inflammation, anti-inflammatory, oxidative stress, vascular and lipid mediators, growth factors, and extracellular matrix breakdown may provide information regarding the toxicity of vaping in e-cig users.

Methods

We collected various biological fluids, i.e. plasma, urine, saliva and exhaled breath condensate (EBC), measured pulmonary function and vaping characteristics, and assessed various biomarkers in e-cig users and nonusers.

Results

The plasma samples of e-cig users showed a significant increase in biomarkers of inflammation (interleukin (IL)-1β, IL-6, IL-8, IL-13, interferon (IFN)-γ, matrix metalloproteinase-9, intercellular cell adhesion molecule-1) and extracellular matrix breakdown (desmosine), and decreased pro-resolving lipid mediators (resolvin D₁ and resolvin D₂). There was a significant increase in growth factor (endothelial growth factor, vascular endothelial growth factor, β-nerve growth factor, platelet-derived growth factor-AA, stem cell factor, hepatocyte growth factor and placental growth factor) levels in plasma of e-cig users versus nonusers. E-cig users showed a significant increase in levels of inflammatory biomarker IFN-γ, oxidative stress biomarker 8-isoprostane and oxidative DNA damage biomarker 8-oxo-dG in urine samples, and of inflammatory biomarker IL-1β in saliva samples. EBC showed a slight increase in levels of triglycerides and 8-isoprostane in e-cig users compared with normal nonusers.

Conclusion

E-cig users have increased levels of biomarkers of inflammation and oxidative stress, reduced pro-resolving anti-inflammatory mediators, and endothelial dysfunction, which may act as risk factors for increasing susceptibility to systemic diseases. The identified noninvasive biomarkers can be used for determining e-cig vaping-associated lung injuries, and for regulatory and diagnostic aspects of vaping in humans.

E-cig use adversely affects oxidative stress and inflammatory responses, and induces tissue remodelling. The identified biomarkers can be used for assessment of vaping-associated lung injuries, and for regulatory and diagnostic aspects of vaping in humans.http://bit.ly/2nxZQ8R

Biomarkers of Exposure and Effect in the Lungs of Smokers, Nonsmokers, and Electronic Cigarette Users

BACKGROUND

Nicotine-containing electronic cigarette (e-cig) use has become widespread. However, understanding the biological impact of e-cigs compared with smoking on the lung is needed. There are major gaps in knowledge for chronic effects and for an etiology to recent acute lung toxicity leading to death among vapers.

METHODS

We conducted bronchoscopies in a cross-sectional study of 73 subjects (42 never-smokers, 15 e-cig users, and 16 smokers). Using bronchoalveolar lavage and brushings, we examined lung inflammation by cell counts, cytokines, genome-wide gene expression, and DNA methylation.

RESULTS

There were statistically significant differences among never-smokers, e-cig users, and smokers for inflammatory cell counts and cytokines (FDR q < 0.1). The e-cig users had values intermediate between smokers and never-smokers, with levels for most of the biomarkers more similar to never-smokers. For differential gene expression and DNA methylation, e-cig users also more like never-smokers; many of these genes corresponded to smoking-related pathways, including those for xenobiotic metabolism, aryl hydrocarbon receptor signaling, and oxidative stress. Differentially methylated genes were correlated with changes in gene expression, providing evidence for biological effects of the methylation associations.

CONCLUSIONS

These data indicate that e-cigs are associated with less toxicity than cigarettes for smoking-related pathways. What is unknown may be unique effects for e-cigs not measured herein, and a comparison of smokers completely switching to e-cigs compared with former smokers. Clinical trials for smokers switching to e-cigs who undergo serial bronchoscopy and larger cross-sectional studies of former smokers with and without e-cig use, and for e-cigs who relapse back to smoking, are needed.

IMPACT

These data can be used for product regulation and for informing tobacco users considering or using e-cigs. What is unknown may be unique effects for e-cigs not measured herein, and clinical trials with serial bronchoscopy underway can demonstrate a direct relationship for changes in lung biomarkers.

Bidirectional Associations among Nicotine and Tobacco Smoke, NeuroHIV, and Antiretroviral Therapy

People living with HIV (PLWH) in the antiretroviral therapy (ART) era may lose more life-years to tobacco use than to HIV. Yet, smoking rates are more than twice as high among PLWH than the general population, contributing not just to mortality but to other adverse health outcomes, including neurocognitive deficits (neuroHIV). There is growing evidence that synergy with chronic inflammation and immune dysregulation that persists despite ART may be one mechanism by which tobacco smoking contributes to neuroHIV. This review will summarize the differential effects of nicotine vs tobacco smoking on inflammation in addition to the effects of tobacco smoke components on HIV disease progression. We will also discuss biomarkers of inflammation via neuroimaging as well as biomarkers of nicotine dependence (e.g., nicotine metabolite ratio). Tobacco smoking and nicotine may impact ART drug metabolism and conversely, certain ARTs may impact nicotine metabolism. Thus, we will review these bidirectional relationships and how they may contribute to neuroHIV and other adverse outcomes. We will also discuss the effects of tobacco use on the interaction between peripheral organs (lungs, heart, kidney) and subsequent CNS function in the context of HIV. Lastly, given the dramatic rise in the use of electronic nicotine delivery systems, we will discuss the implications of vaping on these processes. Despite the growing recognition of the importance of addressing tobacco use among PLWH, more research is necessary at both the preclinical and clinical level to disentangle the potentially synergistic effects of tobacco use, nicotine, HIV, cognition and immune dysregulation, as well as identify optimal approaches to reduce tobacco use. Graphical Abstract Proposed model of the relationships among HIV, ART, smoking, inflammation, and neurocognition. Solid lines represent relationships supported by evidence. Dashed lines represent relationships for which there is not enough evidence to make a conclusion. (a) HIV infection produces elevated levels of inflammation even among virally suppressed individuals. (b) HIV is associated with deficits in cognition function. (c) Smoking rates are higher among PLWH, compared to the general population. (d) The nicotine metabolite ratio (NMR) is associated with smoking behavior. (e) HIV and tobacco use are both associated with higher rates of psychiatric comorbidities, such as depression, and elevated levels of chronic stress. These factors may represent other mechanisms linking HIV and tobacco use. (f) The relationship between nicotine, tobacco smoking, and inflammation is complex, but it is well-established that smoking induces inflammation; the evidence for nicotine as anti-inflammatory is supported in some studies, but not others. (g) The relationship between tobacco use and neurocognition may differ for the effects of nicotine (acute nicotine use may have beneficial effects) vs. tobacco smoking (chronic use may impair cognition). (h) Elevated levels of inflammation may be associated with deficits in cognition. (i) PLWH may metabolize nicotine faster than those without HIV; the mechanism is not yet known and the finding needs validation in larger samples. We also hypothesize that if HIV-infection increases nicotine metabolism, then we should observe an attenuation effect once ART is initiated. (j) It is possible that the increase in NMR is due to ART effects on CYP2A6. (k) We hypothesize that faster nicotine metabolism may result in higher levels of inflammation since nicotine has anti-inflammatory properties.

E-cigarette use increases susceptibility to bacterial infection by impairment of human neutrophil chemotaxis, phagocytosis, and NET formation

E-cigarettes are portrayed as safer relative to conventional tobacco. However, burgeoning evidence suggests that E-cigarettes may adversely affect host defenses. However, the precise mechanisms by which E-cigarette vapor alters innate immune cell function have not been fully elucidated. We determined the effects of E-cigarette exposure on the function and responses to infectious challenge of the most abundant innate immune cell, the neutrophil, using isolated human neutrophils and a mouse model of gram-negative infection. Our results revealed that human neutrophils exposed to E-cigarette vapor had 4.2-fold reductions in chemotaxis toward the bacterial cell-well component f-Met-Leu-Phe (P < 0.001). F-actin polarization and membrane fluidity were also adversely affected by E-cigarette vapor exposure. E-cigarette-exposed human neutrophils exhibited a 48% reduction in production of reactive oxygen species (ROS; P < 0.001). Given the central role of ROS in neutrophil extracellular trap (NET) production, NET production was quantified, and E-cigarette vapor exposure was found to reduce NETosis by 3.5-fold (P < 0.01); formulations with and without nicotine containing propylene glycol exhibiting significant suppressive effects. However, noncanonical NETosis was unaffected. In addition, exposure to E-cigarette vapor lowered the rate of phagocytosis of bacterial bioparticles by 47% (P < 0.05). In our physiological mouse model of chronic E-cigarette exposure and sepsis, E-cigarette vapor inhalation led to reduced neutrophil migration in infected spaces and a higher burden of Pseudomonas. These findings provide evidence that E-cigarette use adversely impacts the innate immune system and may place E-cigarette users at higher risk for dysregulated inflammatory responses and invasive bacterial infections.

Effects of Electronic Cigarette Constituents on the Human Lung: A Pilot Clinical Trial

Electronic cigarette (e-cig) use is continuing to increase, particularly among youth never-smokers, and is used by some smokers to quit. The acute and chronic toxicity of e-cig use is unclear generally in the context of increasing reports of inflammatory-type pneumonia in some e-cig users. To assess lung effects of e-cigs without nicotine or flavors, we conducted a pilot study with serial bronchoscopies over 4 weeks in 30 never-smokers, randomized either to a 4-week intervention with the use of e-cigs containing only 50% propylene glycol (PG) and 50% vegetable glycerine or to a no-use control group. Compliance to the e-cig intervention was assessed by participants sending daily puff counts and by urinary PG. Inflammatory cell counts and cytokines were determined in bronchoalveolar lavage (BAL) fluids. Genome-wide expression, miRNA, and mRNA were determined from bronchial epithelial cells. There were no significant differences in changes of BAL inflammatory cell counts or cytokines between baseline and follow-up, comparing the control and e-cig groups. However, in the intervention but not the control group, change in urinary PG as a marker of e-cig use and inhalation was significantly correlated with change in cell counts (cell concentrations, macrophages, and lymphocytes) and cytokines (IL8, IL13, and TNFα), although the absolute magnitude of changes was small. There were no significant changes in mRNA or miRNA gene expression. Although limited by study size and duration, this is the first experimental demonstration of an impact of e-cig use on inflammation in the human lung among never-smokers.

In Vitro Consequences of Electronic-Cigarette Flavoring Exposure on the Immature Lung

Background: The developing lung is uniquely susceptible and may be at increased risk of injury with exposure to e-cigarette constituents. We hypothesize that cellular toxicity and airway and vascular responses with exposure to flavored refill solutions may be altered in the immature lung. Methods: Fetal, neonatal, and adult ovine pulmonary artery smooth muscle cells (PASMC) were exposed to popular flavored nicotine-free e-cigarette refill solutions (menthol, strawberry, tobacco, and vanilla) and unflavored solvents: propylene glycol (PG) or vegetable glycerin (VG). Viability was assessed by lactate dehydrogenase assay. Brochodilation and vasoreactivity were determined on isolated ovine bronchial rings (BR) and pulmonary arteries (PA). Results: Neither PG or VG impacted viability of immature or adult cells; however, exposure to menthol and strawberry flavored solutions increased cell death. Neonatal cells were uniquely susceptible to menthol flavoring-induced toxicity, and all four flavorings demonstrated lower lethal doses (LD50) in immature PASMC. Exposure to flavored solutions induced bronchodilation of neonatal BR, while only menthol induced airway relaxation in adults. In contrast, PG/VG and flavored solutions did not impact vasoreactivity with the exception of menthol-induced relaxation of adult PAs. Conclusion: The immature lung is uniquely susceptible to cellular toxicity and altered airway responses with exposure to common flavored e-cigarette solutions.

Latent Class Analysis of E-cigarette Use Sessions in Their Natural Environments

BACKGROUND

Delivery of nicotine and substances from electronic nicotine delivery systems, or e-cigarettes, depends in part on how users puff on the devices. Little is known about variation in puffing behavior to inform testing protocols or understand whether puffing behaviors result in increased exposure to emissions.

METHODS

We analyzed puff topography data collected using a wireless portable use monitor (wPUM) continuously over 2 weeks among 34 current second-generation e-cigarette users in their everyday lives. For each puff, the wPUM recorded date, time, duration, volume, flow rate, and inter-puff interval.

RESULTS

We defined use session and classes at the session level using multilevel latent profile analysis, resulting in two session classes and three person types. Session class 1 ("light") was characterized by 14.7 puffs per session (PPS), low puff volume (59.9 ml), flow rate (28.7 ml/s), and puff duration (202.7 s × 100). Session class 2 ("heavy") was characterized by 16.7 PPS with a high puff volume (290.9 ml), flow rate (71.5 ml/s), and puff duration (441.1 s × 100). Person class 1 had almost exclusively "light" sessions (98.0%), whereas person class 2 had a majority of "heavy" sessions (60.7%) and person class 3 had a majority of "light" sessions (75.3%) but some "heavy" sessions (24.7%).

CONCLUSION

Results suggest there are different session topography patterns among e-cigarette users. Further assessment is needed to determine whether some users have increased exposure to constituents and/or health risks because of e-cigarettes.

IMPLICATIONS

Our study examines topography characteristics in a users' natural setting to identify two classes of e-cigarette session behavior and three classes of users. These results suggest that it is important for studies on the health effects of e-cigarettes to take variation in user topography into account. It is crucial to accurately understand the topography profiles of session and user types to determine whether some users are at greater exposure to harmful or potentially harmful constituents and risks from e-cigarettes as they are used by consumers.

A narrative review evaluating the safety and efficacy of e-cigarettes as a newly marketed smoking cessation tool

Introduction:

E-cigarettes are an alternative to traditional tobacco-based cigarettes. While having considerable societal awareness, conflicting evidence exists to support their claims that they are an effective smoking cessation tool and are safe. Currently >7000 flavours exist with evidence that they exhibit detrimental cellular and tissue effects. A literature review was conducted utilising PubMed and Google Scholar Databases identifying papers between 2014 and 2019. The aims of this study were to accurately gauge the safety and efficacy of e-cigarettes as a smoking cessation tool.

Methods:

Search terms including ‘electronic cigarettes’ and ‘vaping’ were used to identify suitable references. A total of 314 articles were identified from which papers were excluded due to risk of bias, insufficient detail or were duplicate from which 58 papers were used in the final review.

Results:

Evidence shows that e-cigarettes can have detrimental effects on several cell lines and animal models with their flavourings and nicotine content implicated; this has, however, not translated into major health outcomes after 3.5 years follow-up but has been linked to chronic lung disease and cardiovascular disease. While advertised as an effective smoking cessation tool, no consensus can be made regarding their effectiveness although the first robust randomised controlled trial reports some success. This, however, is offset by the fact that the most common e-cigarette use is as a dual user and that there is evidence of threefold increased risk of future tobacco smoking.

Conclusion:

Future research is needed to evaluate the long-term health outcomes and efficacy of e-cigarettes as a smoking cessation tool with greater discussion between patients and clinicians regarding this smoking cessation tool.

E-cigarettes and head and neck cancers: A systematic review of the current literature

BACKGROUND

Cigarette smoking is a well-established risk factor for head and neck (HN) cancers. Use of electronic cigarettes (e-cigarettes) is gaining popularity, being advertised as benign alternatives to tobacco. A wide variety of potentially harmful chemical components with variable quantity have been identified in e-liquids and aerosols of e-cigarettes. However, use of e-cigarettes remains controversial due to conflicting evidence.

OBJECTIVES

We aimed to assess the association between e-cigarettes and HN cancers. We conducted a systematic review to evaluate the literature for evidence on carcinogenic effects of e-cigarettes in the pathogenesis of HN cancers.

TYPE OF REVIEW

Qualitative systematic review.

SEARCH STRATEGY

A PubMed/MEDLINE, Cochrane, CINAHL Plus, Trip Medical Database and Web of Science search was done for studies on e-cigarettes and HN cancer.

EVALUATION METHOD

Abstract review of all articles, full article revision of included studies, data extraction and quality assessment were performed by two independent assessors.

RESULTS

The literature search resulted in the identification of 359 articles. Eighteen articles were selected for inclusion into the systematic review. The majority were laboratory-based studies, followed by several cohort and case studies, representing low-level evidence. A few reports suggested DNA damage following exposure to e-cigarettes potentially due to increased oxidative stress. Flavoured e-liquids appear to be more harmful. There is variable evidence from clinical studies.

CONCLUSIONS

Our review outlines potential dangers associated with the use of e-cigarettes and their role in HN cancers. More longitudinal and controlled studies are needed to assess the possible link between e-cigarettes and HN cancers.

Electronic cigarettes and cardiovascular health: what do we know so far?

While tobacco cigarette (TC) smoking has continued to drop to all-time lows, the use of electronic cigarettes (ECs), introduced in the US in 2007, has been rising dramatically, especially among youth. In EC emissions, nicotine is the major biologically active element, while levels of carcinogens and harmful combustion products that typify TC smoke are very low or even undetectable. TCs cause cardiovascular harm by activation of inflammatory pathways and oxidative damage, leading to atherogenesis and thrombosis, as well as through sympathetic activation triggering ischemia and arrhythmia. While ECs are generally believed to be safer than TCs, there remain many uncertainties regarding the overall cardiovascular health effects of EC usage. In this review, we discuss the various components of EC smoke and review the potential mechanisms of cardiovascular injury caused by EC use. We also discuss the controversy regarding the increasing epidemic of youth EC use weighed against the use of ECs as a smoking-cessation aid.

Effects of Smoking on the Prevalence of Allergic Disorders in Russian Adolescents: A Retrospective Cross-sectional Study

Introduction

Smoking is one of the leading causes of death. Smoking also decreases lung efficiency and impairs lung function in children of all ages. Second-hand tobacco smoking increases both the frequency and severity of childhood asthma. However, the role of active tobacco smoking in the manifestation of asthma remains inconclusive. The aim of this article was to describe the current understanding of the prevalence and adverse effects of cigarette smoking and to determine whether there is an association between smoking and the manifestation and progression of asthma among adolescents and high school students in Russia.

Objectives

This study aimed to determine the true prevalence of bronchial asthma (BA), allergic rhinitis (AR), and atopic dermatitis (AD) in the population of adolescents in the Russian Federation. In the GA²LEN (Global Allergy and Asthma European Network) study, we analyzed participant responses to confirm a connection between smoking and asthma exacerbation or development. This study examined the association between parental smoking and childhood atopic disorders. We sought to determine the effects of exposure to environmental tobacco smoke and childhood cigarette smoking on asthma symptoms among high school and college students in Moscow, Russia. We analyzed the reactions to the present tobacco control policy and evaluated the significance of the success of the policy. A number of methods were used, including questionnaires, surveys, and statistical analysis software.

Results

Our research indicates a moderate decrease in smoking prevalence among Russian teenagers. From the data and results of our study, 25.3% of the respondents said that they have ever smoked for as long as a year. Among the participants who had ever smoked, most of them started smoking at the age of 16 years while the state-reported average age for a new smoker is 11.4. Fifty percent of the respondents who had shortness of breath had been woken by an attack once a week in the last three months. Only 21.1% of the people with asthma were taking medicines for it. According to our calculations, there is no significant association between smoking status and the prevalence of asthma, hay fever, and sinusitis. More respondents (34.2%) had fathers who regularly smoked during their childhood than mothers who regularly smoked during their childhood or before the children were born (7.9%). There is a statistically significant association between a mother smoking during childhood or before the birth of a child and that child being hospitalized before the age of two years for lung disease.

Conclusion

The fact that the smoking rates among study participants are relatively low is quite encouraging and anti-smoking campaigns should be intensified to drive the rates lower. The data analyzed do not provide sufficient evidence to show that there is any causative association between smoking status and the development of asthma, hay fever, or sinusitis. Since there is no clear association between smoking status and the development of asthma, hay fever, or allergic sinusitis, it is imperative to say that smoking cessation will have very little effect on allergy prevalence as per the data analyzed. From the conducted analysis, it is evident that there is a clear link between second-hand smoke and asthma in children. According to our results, children whose mothers smoked are especially vulnerable to asthma and other respiratory disorders.

Emissions of Free Radicals, Carbonyls, and Nicotine from the NIDA Standardized Research Electronic Cigarette and Comparison to Similar Commercial Devices

E-cigarettes (e-cigs) are a diverse and continuously evolving group of products with four generations currently in the market. The National Institute on Drug Abuse (NIDA) standardized research e-cigarette (SREC) is intended to provide researchers with a consistent e-cig device with known characteristics. Thus, we conducted laboratory-based characterizations of oxidants and nicotine in aerosols produced from SREC and other closed-system, breath-activated, commercially available e-cigs (Blu and Vuse). We hypothesized that oxidant and nicotine production will be significantly affected in all devices by changes in puffing parameters. All e-cigs were machine vaped and the aerosols generated were examined for nicotine, carbonyls, and free-radicals while varying the puff-volumes and puff-durations to reflect typical human usage. The data were normalized on a per puff, per gram aerosol, and per milligram nicotine basis. We found that aerosol production generally increased with increasing puff-duration and puff-volume in all e-cigs tested. Increased puff-duration and puff-volume increased nicotine delivery for Blu and Vuse but not the SREC. We report, for the first time, reactive free-radicals in aerosols from all closed-system e-cigs tested, albeit at levels lower than cigarette smoke. Formaldehyde, acetaldehyde, acetone, and propionaldehyde were detected in the aerosols of all tested e-cigs. Carbonyl and free radical production is affected by puff-duration and puff volume. Overall, SREC was more efficient at aerosol and nicotine production than both Blu and Vuse. In terms of carbonyl and free radical levels, SREC delivered lower or similar levels to both other devices.

Composition and chemical health hazards of the most common electronic cigarette liquids in nine European countries

BACKGROUND

The aim of the present study was to identify the composition and reported chemical health hazards of the most common electronic cigarette liquids (e-liquids) in nine European Union (EU) Member States (MS) prior to adoption of the Tobacco Product Directive (TPD).

MATERIALS AND METHODS

Within the Horizon2020, EUREST-PLUS study, 122 of the most commonly sold e-liquids in 9 EU MS were randomly selected and purchased. A quantitative and qualitative chemical analysis was performed using a previously validated based gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry method. The most commonly detected compounds were then divided according to the Danger Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and Warning GHS codes.

RESULTS

Within our qualitative analysis, 171 different compounds were detected. Discrepancies in measured versus reported nicotine concentration were identified. Forty-one (85.4%) of the most commonly detected compounds were registered with Warning GHS codes, 11 with Danger GHS codes and 9 with both codes. Of the total number of the detected compounds, 293 were attributable to fruits flavor, followed by tobacco flavor (204), nonalcoholic drinks (n = 64), desserts-sweets (n = 50), menthol - mint (n = 42) and alcohol (n = 39). Menthol which is classified as a strong irritant to skin and eye was the most frequently detected compound.

CONCLUSION

A large plethora of compounds with varying warning codes was identified in e-cigarette samples. The systematic monitoring and chemical evaluation of e-liquids are warranted, so as to ensure consumer protection.

New Challenges: Developing Gendered and Equitable Responses to Involuntary Exposures to Electronic Nicotine Delivery Systems (ENDS) and Cannabis Vaping

Recreational cannabis use is in the process of being legalized in Canada, and new products and devices for both nicotine and cannabis vaping are being introduced. Yet, research on the harms of involuntary exposure to electronic nicotine delivery systems (ENDSs) and cannabis vaping is in its infancy, and there is a lack of investigation on sex-specific health effects and gendered patterns of exposure and use. We argue that responses to ENDS and cannabis vaping exposures should align with policy and progress on restricting exposure to tobacco secondhand smoke (SHS). Furthermore, we argue that sex, gender, and equity considerations should be integrated in both research and policy to benefit all Canadians.

The toxicity of E-cigarettes and children's respiratory health

Electronic cigarettes (E-cig), also referred to as Electronic Nicotine Delivery System (ENDS), were initially developed in 2003 to reduce the harmful effects of tobacco smoking. Since then, E-cig have become widely available in many countries and are used by many young people who would be unlikely to take up cigarette smoking. However, the adverse effects on child health remain largely unknown. E-cigs are available through regulated sale in many countries, but easily accessible by the internet in others. Adverse effects may be ascribed to the nicotine itself, to the accompanying substances in the aerosol (often referred to as vapour) or to temperature modifications of the content. There is a lack of human studies to assess respiratory effects of nicotine exposure to the unborn or young child. Also assessing the effects of the vaping content apart from nicotine is challenging, with the huge variety of exposure by frequency, duration and content, but experimental studies are on the way that may indicate the level of harm by such products. This article will summarize what is currently known about the use of E-cigs in children and in pregnancy, and discuss adverse effects of direct or in utero exposure to E-cig on the respiratory health of children. We thereby hope to provide a background for discussing potential harms to the respiratory system of children by E-cig exposure in pregnancy and early post-natal life, in a setting where an increasing proportion of adolescent and young adults use E-cigs, marketed to be 95% less harmful than conventional cigarettes.

The Intersection of Sex Differences, Tobacco Use, and Inflammation: Implications for Psychiatric Disorders

PURPOSE OF REVIEW

Tobacco use, sex differences, and psychiatric disorders are associated with altered immune function. There are also sex differences in tobacco use and psychiatric disorders. This review summarizes findings from the small, but growing literature examining sex differences in the effects of tobacco use on inflammation and the implications for psychiatric disorders.

RECENT FINDINGS

We identified four studies that tested the interaction between sex and tobacco/nicotine on inflammation. Although males and females generally exhibited differential tobacco-induced immune responses, the pattern varied depending on the sample (rodents vs. humans) and the method to evaluate inflammation. Evidence suggests that sex modulates the effects of tobacco smoke on inflammation. Many inflammation markers associated with sex differences and tobacco use are related to psychiatric disorders. We propose a model in which sex, tobacco use, and inflammation interact to increase risk for psychiatric disorders. Future studies are needed to examine the mechanisms that explain this relationship.

Particle Size Dynamics: Toward a Better Understanding of Electronic Cigarette Aerosol Interactions With the Respiratory System

The knowledge of possible acute and long-term health effects of aerosols inhaled from electronic cigarettes (ECs) is still limited partially due to incomplete awareness of physical phenomena related to EC-aerosol dynamics. This short review discusses the basic processes of aerosol transformation (dynamics) upon inhalation, indicating also the need for the accurate determination of the size of droplets in the inhaled EC-mist. The significance of differences in the aerosol particle size distribution for the prediction of regional deposition of inhaled mist in the respiratory system is highlighted as a decisive factor in the interactions of inhaled EC-aerosols with the organism.

Children and E-Cigarettes: A New Threat to Health

The widespread availability and use of E-Cigarettes in many countries has established the need for an assessment of their effect on children. By the end of 2017 the number published annually on E-Cigarettes had increased to 2976 and included 171 papers on E-Cigarettes and children. The objective of this commentary is to provide a review and public health perspective on the effects of E-cigarettes on children. There are four public health questions to be answered:

1. Are E-Cigarettes and replenishing fluids toxic on accidental ingestion?

2. If children smoke E-Cigarettes is this harmful?

3. Does exposure to second hand vapour from E-Cigarettes cause harm to children?

4. Are children (adolescents) who use E Cigarettes more likely to begin smoking conventional cigarettes?

There were 2229 reported exposures to e-cigarette fluids and liquid nicotine in the USA in 2017 causing cardiovascular symptoms of varying severity. No deaths were reported although the potential is always there. Exposure to E-Cigarette vapor is less dangerous than cigarette smoke. However it does damage pulmonary endothelium in experimental models. No long term studies are yet available on chronic diseases although vapor does contain carcinogens. Adolescents who use E-Cigarettes are more likely to become tobacco smokers. Because of the accumulating evidence of harm to children great caution should be exercised in widening the public promotion and usage of E-Cigarettes. Children should avoid any contact with E-cigarettes or their vapour.

Socioeconomic status and adolescent e-cigarette use: The mediating role of e-cigarette advertisement exposure

Among adolescents, low socioeconomic status (SES) is associated with greater exposure to tobacco cigarette advertising and cigarette use. However, associations among SES, e-cigarette advertising and e-cigarette use are not well understood. This study examined exposure to e-cigarette advertisements as a mediator of the relationship between SES and adolescent e-cigarette use. Adolescents (N = 3473; 51% Female) from 8 high schools in Connecticut completed an anonymous survey in Spring 2015. Mediation analysis was used to examine whether the total number of sources of recent e-cigarette advertising exposure (e.g., TV, radio, billboards, magazines, local stores [gas stations, convenience stores], vape shops, mall kiosks, tobacco shops, social media) mediated the association between SES (measured by the Family Affluence Scale) and past-month frequency of e-cigarette use. We clustered for school and controlled for other tobacco product use, age, sex, race/ethnicity and perceived social norms for e-cigarette use in the model. Our sample recently had seen advertisements via 2.1 (SD = 2.8) advertising channels. Mediation was supported (indirect effect: β = 0.01, SE = 0.00, 95% CI [0.001, 0.010], p = 0.02), such that higher SES was associated with greater recent advertising exposure, which, in turn, was associated with greater frequency of e-cigarette use. Our study suggests that regulations to reduce youth exposure to e-cigarette advertisement may be especially relevant to higher SES youth. Future research should examine these associations longitudinally and evaluate which types of advertisements target different SES groups.

Weighing the Risks and Benefits of Electronic Cigarette Use in High-Risk Populations

This article reviews the current evidence on electronic cigarette (e-cigarette) safety and efficacy for smoking cessation, with a focus on smokers with cardiovascular disease, pulmonary disease, or serious mental illness. In the United States, adult smokers use e-cigarettes primarily to quit or reduce cigarette smoking. An understanding of the potential risks and benefits of e-cigarette use may help clinicians counsel smokers about the potential impact of e-cigarettes on health.

Diffuse Alveolar Hemorrhage Induced by Vaping

There has been a significant increase in electronic cigarette (e-cigarette) use since its introduction in 2007. Ironically, there remains very few published literature on the respiratory complications of e-cigarettes. The use of personalized vaporizers or commonly known as “vaping” has started to overtake standard e-cigarette. Its dynamic vaporizer customization makes it challenging to assess long-term health effects. Case reports on the pulmonary complications of e-cigarettes are limited to bronchiectasis, eosinophilic pneumonia, pleural effusion, and suspected hypersensitivity pneumonitis. Diffuse alveolar hemorrhage (DAH) is bleeding into the alveolar spaces of the lung secondary to disruption of the alveolar-capillary basement membrane. We report a case of young male presenting with subacute respiratory failure. He was later found to have diffuse alveolar hemorrhage syndrome that is likely induced by aggressive vaping. This adds up to the rising concern on the possible serious complications of this innovative technology designed as a safer alternative to traditional cigarettes.

Perceptions of non-traditional tobacco products between asthmatic and non-asthmatic college students

OBJECTIVE

Electronic nicotine delivery systems (ENDS) use is common among college students and there are perceptions that ENDS are not as harmful as traditional cigarettes. The aim of this study was to examine differences in ENDS use, risk perceptions, and co-occurring smoking behaviors between college students with and without asthma.

METHODS

The study consisted of a cross-sectional online survey with a final sample size of 898 college students. The voluntary participation survey was disseminated to all undergraduate and graduate students at a mid-sized liberal arts university in the Southeast U.S. in the Fall of 2014.

RESULTS

Approximately 19.7% reported that they had been previously diagnosed with asthma. Forty three percent of participants (n = 384) used ENDS in the past 30 days. Equivalent percentages of college students with asthma (46.9%) and college students without asthma (46.9%) have tried ENDS. Overall participants indicated that they perceived ENDS use as less (44%) or equally (38%) as harmful as cigarettes. College students with asthma had 2.85 (95% CI: 1.18-6.89) greater odds of being in the poly-user class, which was characterized by dual use of ENDS, combustible cigarettes, hookah, and marijuana.

CONCLUSIONS

In this study, college students with asthma were similar to their peers with regard to their use of ENDS and related risk perceptions; however, a small subsample of those with asthma exhibited problematic smoking behaviors characterized by dual use of multiple tobacco products including marijuana.

Organizing pneumonia related to electronic cigarette use: A case report and review of literature

BACKGROUND AND OBJECTIVE

Electronic cigarettes (e cigarettes) are battery operated devices that produce aerosol by heating a solution typically made up of nicotine, propylene glycol, glycerin and flavouring agents. The use of e cigarettes has risen dramatically in recent years especially among adolescents and young adults. These devices have been marketed as safer alternatives to tobacco smoking by their manufactures despite lack of adequate safety data.

METHODS

We present a case of 40-year-old female patient who developed significant pulmonary toxicity secondary to e cigarette use and searched existing literature relevant to the case.

RESULTS

To our knowledge this is the second reported case of organizing pneumonia and tenth reported case of pulmonary toxicity related to e cigarette use. Our patient presented with symptoms of worsening dyspnoea and intermittent chest pain for past 1 month. She reported increased use of e cigarettes during this time period to help her quit smoking. Patient developed acute hypoxemic respiratory failure requiring intubation and mechanical ventilation. She was diagnosed with organizing pneumonia on open lung biopsy and was successfully treated with steroids along with abstinence from e cigarette use.

CONCLUSIONS

As the current data on health effects of e cigarettes is limited, case reports can serve important piece of information in this regard. The use of e cigarettes has increased exponentially in recent years and continue to rise; therefore, physicians should be aware of adverse effects and toxicity related to its use.

An Online Survey of New Zealand Vapers

Using electronic cigarettes (vaping) is controversial, but is increasingly widespread. This paper reports the results of an electronic survey of vapers in New Zealand, a country where the sale and supply of e-liquids containing nicotine is illegal, although vapers can legally access e-liquids from overseas. An on-line survey was conducted, using vaper and smoking cessation networks for recruitment, with follow up surveys conducted 1 and 2 months after the initial survey. 218 participants were recruited. Almost all had been smokers, but three quarters no longer smoked, with the remainder having significantly reduced their tobacco use. Three participants were non-smokers before starting to vape, but none had gone on to become smokers. The overriding motivation to begin and continue vaping was to stop or to reduce smoking. The results were consistent with a progression from initially both vaping and smoking using less effective electronic cigarette types, then moving to more powerful devices, experimentation with flavors and nicotine strengths—all resulting in reducing or stopping tobacco use. Lack of access to nicotine and lack of support for their chosen cessation method were the main problems reported. Vaping had resulted in effective smoking cessation for the majority of participants.

Lung Toxicity of Condensed Aerosol from E-CIG Liquids: Influence of the Flavor and the In Vitro Model Used

The diffusion of e-cigarette (e-CIG) opens a great scientific and regulatory debate about its safety. The huge number of commercialized devices, e-liquids with almost infinite chemical formulations and the growing market demand for a rapid and efficient toxicity screen system that is able to test all of these references and related aerosols. A consensus on the best protocols for the e-CIG safety assessment is still far to be achieved, since the huge number of variables characterizing these products (e.g., flavoring type and concentration, nicotine concentration, type of the device, including the battery and the atomizer). This suggests that more experimental evidences are needed to support the regulatory frameworks. The present study aims to contribute in this field by testing the effects of condensed aerosols (CAs) from three main e-liquid categories (tobacco, mint, and cinnamon as food-related flavor), with (18 mg/mL) or without nicotine. Two in vitro models, represented by a monoculture of human epithelial alveolar cells and a three-dimensional (3D) co-culture of alveolar and lung microvascular endothelial cells were used. Cell viability, pro-inflammatory cytokines release and alveolar-blood barrier (ABB) integrity were investigated as inhalation toxicity endpoints. Results showed that nicotine itself had almost no influence on the modulation of the toxicity response, while flavor composition did have. The cell viability was significantly decreased in monoculture and ABB after exposure to the mints and cinnamon CAs. The barrier integrity was significantly affected in the ABB after exposure to cytotoxic CAs. With the exception of the significant IL-8 release in the monoculture after Cinnamon exposure, no increase of inflammatory cytokines (IL-8 and MCP-1) release was observed. These findings point out that multiple assays with different in vitro models are able to discriminate the acute inhalation toxicity of CAs from liquids with different flavors, providing the companies and regulatory bodies with useful tools for the preliminary screening of marketable products.