E-cigarettes and their lone constituents induce cardiac arrhythmia and conduction defects in mice

From smoke to stroke: quantifying the impact of smoking on stroke prevalence

PURPOSE

The objective of this study is to assess the impact of smoking on stroke prevalence and to delineate the relationship between smoking-related factors and the risk of stroke, incorporating an analysis of demographic variations influencing this association.

METHODS

Our analysis encompassed 9,176 participants, evaluating clinical attributes alongside smoking-related characteristics such as duration of cigarette consumption, and levels of nicotine, tar, and carbon monoxide. We employed weighted univariate logistic regression and restricted cubic splines to examine the association between smoking indicators and stroke risk, complemented by subgroup analyses for demographic differentiation.

RESULTS

The overall prevalence of stroke in our cohort was 3.4%. Statistically significant associations were found between stroke incidence and factors such as age, gender, education, and marital status (p < 0.05). Adjusted logistic regression models showed increased odds ratios (ORs) for stroke with higher nicotine and carbon monoxide levels across progressively adjusted models: Model 1 (unadjusted), Model 2 (adjusted for age, gender), Model 3 (further adjusted for education, marital status, BMI, PIR), and Model 4 (fully adjusted for additional factors including hypertension, hyperlipidemia, diabetes, and drinking). Specifically, ORs for nicotine increased from 2.39 in Model 1 to 2.64 in Model 4; for carbon monoxide, from 1.10 to 1.11 over the same models.​The threshold analysis using restricted cubic splines revealed critical points for stroke risk increase at smoke exposure levels of 410 units, tar 12 mg, nicotine 1.1 mg, and carbon monoxide 12 ppm. Above these thresholds, stroke risk escalates significantly. Additionally, the presence of family smoking history was associated with higher stroke risks compared to those without such history.

CONCLUSION

This study confirms that smoking significantly contributes to increased stroke risk, particularly through exposure to nicotine and carbon monoxide. The findings emphasize the necessity for tailored stroke prevention strategies that specifically address smoking behaviors and consider demographic susceptibilities. Incorporating smoking-related indicators into risk assessment models could enhance the precision of stroke prevention efforts.

An electron paramagnetic resonance time-course study of oxidative stress in the plasma of electronic cigarette exposed rats

The long-term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3 days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4-month-old male Sprague-Dawley rats that were exposed to either air (n = 5) or 1 h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1-4, 24, 48 and 72 h postexposure, n = 4 or 5 in each time group). The EPR analyses were performed using the redox-sensitive hydroxylamine spin probe 1-hydroxy-3-carboxymethyl-2,2,5,5-tetramethyl-pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM• radical was significantly increased in plasma at 1-4, 24 and 48 h (P < 0.05, respectively) and returned to control (air) levels by 72 h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson's P = 0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1 h vaping session can negatively influence vascular health for up to 3 days after vaping. HIGHLIGHTS: What is the central question of this study? Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction? What is the main finding and its importance? Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1 h exposure to electronic cigarette aerosol takes ≤72 h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.

LDHA contributes to nicotine induced cardiac fibrosis through autophagy flux impairment

Cardiac fibrosis is a typical feature of cardiac pathological remodeling, which is associated with adverse clinical outcomes and has no effective therapy. Nicotine is an important risk factor for cardiac fibrosis, yet its underlying molecular mechanism remains poorly understood. This study aimed to identify its potential molecular mechanism in nicotine-induced cardiac fibrosis. Our results showed nicotine exposure led to the proliferation and transformation of cardiac fibroblasts (CFs) into myofibroblasts (MFs) by impairing autophagy flux. Through the use of drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and surface plasmon resonance (SPR) technology, it was discovered that nicotine directly increased the stability and protein levels of lactate dehydrogenase A (LDHA) by binding to it. Nicotine treatment impaired autophagy flux by regulating the AMPK/mTOR signaling pathway, impeding the nuclear translocation of transcription factor EB (TFEB), and reducing the activity of cathepsin B (CTSB). In vivo, nicotine treatment exacerbated cardiac fibrosis induced in spontaneously hypertensive rats (SHR) and worsened cardiac function. Interestingly, the absence of LDHA reversed these effects both in vitro and in vivo. Our study identified LDHA as a novel nicotine-binding protein that plays a crucial role in mediating cardiac fibrosis by blocking autophagy flux. The findings suggest that LDHA could potentially serve as a promising target for the treatment of cardiac fibrosis.

Formaldehyde and the Transient Receptor Potential Ankyrin-1 Contribute to Electronic Cigarette Aerosol-induced Endothelial Dysfunction in Mice

Electronic Nicotine Delivery Systems (ENDS) aerosol exposures can induce endothelial dysfunction (ED) in healthy young humans and animals. Thermal degradation of ENDS solvents, propylene glycol and vegetable glycerin (PG: VG), generates abundant formaldehyde (FA) and other carbonyls. Because FA can activate the transient receptor potential ankyrin-1 (TRPA1) sensor, we hypothesized that FA in ENDS aerosols provokes TRPA1-mediated changes that include ED and 'respiratory braking' - biomarkers of harm. To test this, wild-type (WT) and TRPA1-null mice were exposed by inhalation to either filtered air, PG: VG-derived aerosol, or formaldehyde (FA, 5 ppm). Short-term exposures to PG: VG and FA induced ED in female WT but not in female TRPA1-null mice. Moreover, acute exposures to PG: VG and FA stimulated respiratory braking in WT but not in TRPA1-null female mice. Urinary metabolites of FA (ie, N  -1,3-thiazolidine-4-carboxylic acid, TCA; N  -1,3-thiazolidine-4-carbonyl glycine, TCG) and monoamines were measured by LC-MS/MS. PG: VG and FA exposures significantly increased urinary excretion of both TCA and TCG in both WT and TRPA1-null mice. To confirm that inhaled FA directly contributed to urinary TCA, mice were exposed to isotopic 13C-FA gas (1 ppm, 6 h).13C-FA exposure significantly increased the urine level of 13C-TCA in the early collection (0-3 h) supporting a direct relationship between inhaled FA and TCA. Collectively, these data suggest that ENDS use may increase CVD risk dependent on FA, TRPA1, and catecholamines, yet independently of either nicotine or flavorants. This study supports that levels of FA in ENDS-derived aerosols should be lowered to mitigate CVD risk in people who use ENDS.

Arrhythmogenic effects of acute electronic cigarette compared to tobacco cigarette smoking in people living with HIV

The leading cause of death in people living with HIV (PLWH) is cardiovascular disease, and the high prevalence of tobacco cigarette (TC) smoking is a major contributor. Switching to electronic cigarettes (ECs) has been promoted as a harm reduction strategy. We sought to determine if acute EC compared to TC smoking had less harmful effects on arrhythmogenic risk factors including acute changes in hemodynamics, heart rate variability (HRV), and ventricular repolarization (VR). In PLWH who smoke, changes in hemodynamics, HRV, and VR were compared pre/post acutely using an EC, TC, or puffing on an empty straw on different days in random order, in a crossover study. Thirty-seven PLWH (36 males, mean age 40.5 ± 9.1 years) participated. Plasma nicotine was greater after TC versus EC use (10.12 ± 0.96 vs. 6.18 ± 0.99 ng/mL, respectively, p = 0.004). HR increased significantly, and similarly, after acute EC and TC smoking compared to control. Changes in HRV that confer increased cardiac risk (LF/HF ratio) were significantly smaller after acute EC versus TC use, consistent with a harm reduction effect. In a post-hoc analysis of PLWH with and without positive concurrent recreational drug use as indicated by point of care urine toxicology testing, this differential effect was only seen in PLWH not currently using recreational drugs. Changes in VR were not different among the three exposures. In PLWH who smoke, EC compared to TC smoking resulted in smaller adverse changes in HRV. This differential effect was accompanied by a smaller increase in plasma nicotine, and was negated by concurrent recreational drug use. Additional studies are warranted in this vulnerable population disproportionately affected by tobacco-related health disparities.

Micronano Synergetic Three-Dimensional Bioelectronics: A Revolutionary Breakthrough Platform for Cardiac Electrophysiology

Cardiovascular diseases (CVDs) are the leading cause of mortality and therefore pose a significant threat to human health. Cardiac electrophysiology plays a crucial role in the investigation and treatment of CVDs, including arrhythmia. The long-term and accurate detection of electrophysiological activity in cardiomyocytes is essential for advancing cardiology and pharmacology. Regarding the electrophysiological study of cardiac cells, many micronano bioelectric devices and systems have been developed. Such bioelectronic devices possess unique geometric structures of electrodes that enhance quality of electrophysiological signal recording. Though planar multielectrode/multitransistors are widely used for simultaneous multichannel measurement of cell electrophysiological signals, their use for extracellular electrophysiological recording exhibits low signal strength and quality. However, the integration of three-dimensional (3D) multielectrode/multitransistor arrays that use advanced penetration strategies can achieve high-quality intracellular signal recording. This review provides an overview of the manufacturing, geometric structure, and penetration paradigms of 3D micronano devices, as well as their applications for precise drug screening and biomimetic disease modeling. Furthermore, this review also summarizes the current challenges and outlines future directions for the preparation and application of micronano bioelectronic devices, with an aim to promote the development of intracellular electrophysiological platforms and thereby meet the demands of emerging clinical applications.

Electronic cigarettes and cardiovascular disease: epidemiological and biological links

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.

A case report of vaping-associated sudden cardiac arrest in a young healthy patient

Introduction and importance

While vaping has increased significantly among young individuals, the effects of vape aerosol constituents on cardiac electrophysiological dynamics remain unknown.

Case presentation

A 22-year-old female with a history of energy vaping presented with cardiac arrest. Found to have no pulse, CPR was started and an initial rhythm of ventricular tachycardia was obtained. Shock was administered with a follow-up rhythm of ventricular fibrillation. She was emergently defibrillated and entered atrial fibrillation with rapid ventricular response. Toxicology and troponins were all negative. Left heart catheterization and cardiac MRI were unremarkable. She was discharged with an external defibrillation vest and a tentative plan for outpatient electrophysiology study in the setting of negative work-up for cardiopulmonary arrest.

Clinical discussion

Vaping-induced sudden cardiac arrest may be attributed to a reduction in cardiac repolarization reserve. Exposure to vegetable glycerin and propylene glycol, substances present in nearly all vape products, have been found to incite arrhythmias and disrupt cardiac conduction in animals. Acrolein, an aldehyde byproduct of glycerin, has also been found to induce arrhythmias due to autonomic dysfunction. Increased intracellular calcium concentration and free radical damage, which occur as a result of inhaling particulate matter generated from e-cigarettes, further propagates the risk of arrhythmia.

Conclusion

The effects of inhaling vape aerosols remain not fully understood. While there is a perceived notion that nicotine-free aerosols may be harmless, that remains unclear. Further studies are needed to evaluate proarrhythmogenic effects and autonomic dysfunction from the various chemical substances present in vape aerosols.

Addressing Cardiovascular Toxicity Risk of Electronic Nicotine Delivery Systems in the Twenty-First Century: "What Are the Tools Needed for the Job?" and "Do We Have Them?"

Cigarette smoking is positively and robustly associated with cardiovascular disease (CVD), including hypertension, atherosclerosis, cardiac arrhythmias, stroke, thromboembolism, myocardial infarctions, and heart failure. However, after more than a decade of ENDS presence in the U.S. marketplace, uncertainty persists regarding the long-term health consequences of ENDS use for CVD. New approach methods (NAMs) in the field of toxicology are being developed to enhance rapid prediction of human health hazards. Recent technical advances can now consider impact of biological factors such as sex and race/ethnicity, permitting application of NAMs findings to health equity and environmental justice issues. This has been the case for hazard assessments of drugs and environmental chemicals in areas such as cardiovascular, respiratory, and developmental toxicity. Despite these advances, a shortage of widely accepted methodologies to predict the impact of ENDS use on human health slows the application of regulatory oversight and the protection of public health. Minimizing the time between the emergence of risk (e.g., ENDS use) and the administration of well-founded regulatory policy requires thoughtful consideration of the currently available sources of data, their applicability to the prediction of health outcomes, and whether these available data streams are enough to support an actionable decision. This challenge forms the basis of this white paper on how best to reveal potential toxicities of ENDS use in the human cardiovascular system-a primary target of conventional tobacco smoking. We identify current approaches used to evaluate the impacts of tobacco on cardiovascular health, in particular emerging techniques that replace, reduce, and refine slower and more costly animal models with NAMs platforms that can be applied to tobacco regulatory science. The limitations of these emerging platforms are addressed, and systems biology approaches to close the knowledge gap between traditional models and NAMs are proposed. It is hoped that these suggestions and their adoption within the greater scientific community will result in fresh data streams that will support and enhance the scientific evaluation and subsequent decision-making of tobacco regulatory agencies worldwide.

Nicotine Formulation Influences the Autonomic and Arrhythmogenic Effects of Electronic Cigarettes

INTRODUCTION

Evidence is mounting that electronic cigarette (e-cig) use induces cardiac sympathetic dominance and electrical dysfunction conducive to arrhythmias and dependent upon nicotine. A variety of nicotine types and concentrations are available in e-cigs, but their relative cardiovascular effects remain unclear. Here we examine how different nicotine forms (racemic, free base, and salt) and concentrations influence e-cig-evoked cardiac dysfunction and arrhythmogenesis and provide a mechanism for nicotine-salt-induced autonomic imbalance.

METHODS

ECG-telemetered C57BL/6J mice were exposed to filtered air (FA) or e-cig aerosols from propylene glycol and vegetable glycerin solvents either without nicotine (vehicle) or with increasing nicotine concentrations (1%, 2.5%, and 5%) for three 9-minute puff sessions per concentration. Spontaneous ventricular premature beat (VPB) incidence rates, heart rate, and heart rate variability (HRV) were compared between treatments. Subsequently, to test the role of β1-adrenergic activation in e-cig-induced cardiac effects, mice were pretreated with atenolol and exposed to either FA or 2.5% nicotine salt.

RESULTS

During puffing and washout phases, ≥2.5% racemic nicotine reduced heart rate and increased HRV relative to FA and vehicle controls, indicating parasympathetic dominance. Relative to both controls, 5% nicotine salt elevated heart rate and decreased HRV during washout, suggesting sympathetic dominance, and also increased VPB frequency. Atenolol abolished e-cig-induced elevations in heart rate and declines in HRV during washout, indicating e-cig-evoked sympathetic dominance is mediated by β1-adrenergic stimulation.

CONCLUSIONS

Our findings suggest that inhalation of e-cig aerosols from nicotine-salt-containing e-liquids could increase the cardiovascular risks of vaping by inducing sympathetic dominance and cardiac arrhythmias.

IMPLICATIONS

Exposure to e-cig aerosols containing commercially relevant concentrations of nicotine salts may increase nicotine delivery and impair cardiac function by eliciting β1-adrenoceptor-mediated sympathoexcitation and provoking ventricular arrhythmias. If confirmed in humans, our work suggests that regulatory targeting of nicotine salts through minimum pH standards or limits on acid additives in e-liquids may mitigate the public health risks of vaping.

Long-term effects of chronic exposure to electronic cigarette aerosol on the cardiovascular and pulmonary system in mice: A comparative study to cigarette smoke

Electronic cigarettes (e-cigarettes) have rapidly gained popularity as alternatives to traditional combustible cigarettes. However, their long-term health impact remains uncertain. This study aimed to investigate the effects of chronic exposure to e-cigarette aerosol (ECA) in mice compared to conventional cigarette smoke (CS) exposure. The mice were exposed to air (control), low, medium, or high doses of ECA, or a reference CS dose orally and nasally for eight months. Various cardiovascular and pulmonary assessments have been conducted to determine the biological and prosthetic effects. Histopathological analysis was used to determine structural changes in the heart and lungs. Biological markers associated with fibrosis, inflammation, and oxidative stress were investigated. Cardiac proteomic analysis was applied to reveal the shared and unique protein expression changes in ECA and CS groups, which related to processes such as immune activation, lipid metabolism, and intracellular transport. Overall, chronic exposure to ECA led to adverse cardiovascular and pulmonary effects in mice, although they were less pronounced than those of CS exposure. This study provides evidence that e-cigarettes may be less harmful than combustible cigarettes for the long-term health of the cardiovascular and respiratory systems in mice. However, further human studies are needed to clarify the long-term health risks associated with e-cigarette use.

The Rising Use of E-Cigarettes: Unveiling the Health Risks and Controversies

The use of e-cigarettes has tremendously increased in recent times due to the widespread availability of e-cigarettes in diverse flavors, reduced cost compared to regular cigarettes, and misconception of being comparatively safe, which have led to around 2.55 million US middle and high school students smoking e-cigarettes. These devices use a nicotine-rich liquid, which is aerosolized electronically, producing vapors that may also include hazardous chemicals and heavy metals. E-cigarettes are associated with e-cigarette or vaping-associated lung injury, which presents as an acute respiratory ailment mirroring various pulmonary diseases. Additionally, it causes endothelial dysfunction, alters blood lipid profile by elevating circulating levels of low-density lipoprotein cholesterol, increases sympathetic tone, and is found to correlate with arterial stiffening, hence negatively affecting respiratory, cardiovascular, and overall health. We aim to provide a comprehensive analysis of the data on e-cigarettes and their harmful effects on health in comparison to conventional cigarette use by highlighting the pathophysiology of e-cigarette-induced adverse effects and critically analyzing the data both in favor and against its use. Our review concludes that no matter how much nicotine an e-cigarette contains, evidence shows that using it increases the risk of cardiovascular disease, albeit maybe not as much as smoking regular tobacco. Nonetheless, it is crucial to note that the long-term effects of e-cigarette usage are still not fully understood, and existing data have provided opposing viewpoints.

Temporal Association Between Vaping and Risk of Cardiac Events

OBJECTIVE

To describe our early observations with sudden cardiac arrest (SCA) and sudden death (SD) in patients using vape products.

PATIENTS AND METHODS

A retrospective analysis of Mayo Clinic's Windland Smith Rice Genetic Heart Rhythm Clinic and Sudden Death Genomics Laboratory was performed on all SCA survivors and decedents who presented between January 1, 2007, and December 31, 2021, to identify patients/decedents with a history of vaping. Data abstraction included patient demographics, clinical characteristics, and documented use of vape products.

RESULTS

Among 144 SCA survivors and 360 SD victims, there were six individuals (1%; 3 females) with unexplained SCA (n=4) or SD (n=2) that was temporally associated with vaping use with a mean age at sentinel event of 23±5 years. The SCA survivors include a 19-year-old male who was resuscitated from documented ventricular fibrillation 40 minutes after vaping and a 19-year-old male who was resuscitated from ventricular fibrillation a few hours post vaping. The first SD victim was a 19-year-old female with exercise-induced asthma who died in her sleep after vaping that evening. Autopsy results showed eosinophilic infiltrates in the lung tissue and death was attributed to bronchial asthma. The second vaping-associated death involved a 26-year-old male whose autopsy attributed the death to acute respiratory distress syndrome.

CONCLUSION

We have identified six young individuals with a history of vaping who experienced a near fatal episode or a tragic SD. Although larger cohort studies are needed to quantify the actual risk of SD, it seems prudent to sound an early warning about vaping's potential lethality.

Acute cardiovascular effects of 4th generation electronic cigarettes and combusted cigarettes: implications for harm reduction

The health consequences associated with using electronic cigarettes (ECs) are of great public interest because of their potential role in smoking cessation. In 110 participants, including 41 nonusers, 34 people who exclusively use ECs (EC group), and 35 people who smoke tobacco cigarettes (TCs) including 12 dual users (collectively called the TC-D group), the heart rate (HR), blood pressure (BP), and heart rate variability (HRV) were compared at baseline. People in the EC or the TC-D groups were also compared after using a 4th generation EC with or without nicotine, a TC with or without nicotine (TC-D group only), and a straw-control. Baseline HR, BP, and HRV parameters were not different among the EC, the TC-D, and nonuser groups. In people who exclusively use ECs, acute nicotine-EC use increased HR and BP, and produced changes in HRV patterns suggestive of increased cardiac sympathetic influence. In people in the TC-D group, BP increased similarly after acutely smoking a nicotine-TC or a nicotine-EC. However, the increase in HR was significantly greater after smoking a TC compared with the nicotine-EC despite similar acute increases in plasma nicotine. Overall, all exposures containing nicotine significantly increased HR and BP in both cohorts when compared with non-nicotine exposures. Since acute EC use 1) produces an abnormal HRV pattern associated with increased cardiac sympathetic tone in people who chronically use ECs, and 2) similar hemodynamic increases compared with acute TC smoking in people who chronically smoke TCs including dual users, the role of ECs as part of a harm reduction strategy is questioned.NEW & NOTEWORTHY We found that nicotine, not the non-nicotine constituents in tobacco cigarette (TC) or electronic cigarette (EC) emissions, may be the instigator of the acute, potentially adverse, changes in hemodynamics and heart rate variability (HRV) that were recorded several minutes after tobacco product use. Furthermore, acute EC use produced an abnormal HRV pattern associated with increased cardiac risk in people who chronically smoke ECs and produced similar hemodynamic increases compared with acute TC use in people who chronically smoke TCs, including people who are dual users.

Smoking-associated Electrocardiographic Abnormalities Predict Cardiovascular Mortality: Insights from NHANES

Background—

Smoking is associated with arrhythmia and sudden cardiac death, but the biological mechanisms remain unclear. Abnormal electrocardiogram (ECG) durations of ventricular repolarization (QT interval), atrial depolarization (P wave), and atrioventricular depolarization (PR interval and segment), predict cardiac arrhythmia and mortality.

Objectives—

To elucidate how smoking affects cardiac excitation, we assessed in a nationally representative sample (NHANES III) associations between cotinine, abnormalities in P duration, PR interval, PR segment, rate-corrected QT (QTc), QRS duration, and JT interval, and long-term mortality.

Methods—

We analyzed data from 5,633 adults using survey-weighted multinomial logistic regression to estimate associations between tobacco use (>15 ng/ml serum cotinine) and short (<5th percentile) or long (>95th percentile) ECG intervals, relative to reference (5 - 95th percentile).

Results—

After adjustment for demographics, risk factors, and conduction-altering medications, smoking was associated with a higher odds of short PR interval, PR segment, and QRS, and long JT. Broader ECG effects of smoking were also assessed by survey-weighted linear regression of continuous cotinine and ECG intervals, which revealed cotinine inversely associated with PR segment and QTc. Over a 22-year follow-up, many ECG abnormalities predicted cardiovascular mortality in smokers, including long JT, QRS, and QTc, and short QRS.

Conclusions—

Smoking increases likelihood for rapid atrioventricular conduction, rapid ventricular depolarization, and slow ventricular repolarization. The ventricular electrophysiologic abnormalities associated with smoking also predict cardiovascular mortality in smokers; however, traditional ECG measures of cardiac risk like QTc can overlook these ventricular defects and their independent predictive value in smokers.

Sex Differences in E-Cigarette Use and Related Health Effects

BACKGROUND

Electronic cigarettes (e-cigarettes) comprise a variety of products designed to deliver nicotine, flavorings, and other substances. To date, multiple epidemiological and experimental studies have reported a variety of health issues associated with their use, including respiratory toxicity, exacerbation of respiratory conditions, and behavioral and physiological effects. While some of these effects appear to be sex- and/or gender-related, only a portion of the research has been conducted considering these variables. In this review, we sought to summarize the available literature on sex-specific effects and sex and gender differences, including predictors and risk factors, effects on organ systems, and behavioral effects.

METHODS

We searched and selected articles from 2018-2023 that included sex as a variable or reported sex differences on e-cigarette-associated effects.

RESULTS

We found 115 relevant studies published since 2018 that reported sex differences in a variety of outcomes. The main differences reported were related to reasons for initiation, including smoking history, types of devices and flavoring, polysubstance use, physiological responses to nicotine and toxicants in e-liquids, exacerbation of lung disease, and behavioral factors such as anxiety, depression, sexuality, and bullying.

CONCLUSIONS

The available literature supports the notion that both sex and gender influence the susceptibility to the negative effects of e-cigarette use. Future research needs to consider sex and gender variables when addressing e-cigarette toxicity and other health-related consequences.

Development and validation of a method for preparing heated tobacco product aerosol condensate (HTPAC) for large-scale toxicity data acquisition

A method of preparing heated tobacco product aerosol condensate (HTPAC) was developed to expedite HTP toxicity evaluation, and the effectiveness was assessed. To prepare HTPAC, HTP aerosol was generated and collected using a Cambridge filter (particulate phase) and Dulbecco's phosphate buffered saline (DPBS; gaseous phase). The aerosol collected on the Cambridge filter was extracted using methanol, which was thereafter removed by nitrogen purging. The HTP aerosol residue was mixed with DPBS loaded with the collected HTP vapor, ultimately yielding HTPAC. Nicotine and formaldehyde, key harmful compounds in HTP aerosol, were detected in HTPAC (901 ± 224 and 22.2 ± 3.90 µg stick-1, respectively, comparable to those in HTP aerosol (990-1350 (nicotine) and 2.33-21.9 µg stick-1 (formaldehyde)). Propylene glycol and vegetable glycerin, which influence the amount of HTP aerosol, were detected at similar levels in HTPAC and HTP aerosol (propylene glycol = 616 ± 57.1 (HTPAC) and 320-630 µg stick-1 (aerosol) and vegetable glycerin = 2418 ± 224 (HTPAC) and 1667-4000 µg stick-1 (aerosol)). Known components of HTP aerosol (hydroxyacetone, acetic acid, triacetin, and 2-furanmethanol) were also detected in HTPAC. Consequently, HTPAC offers an effective method for concentrating harmful compounds found in HTP aerosols. This, in turn, facilitates comprehensive toxicity assessments, paving the way for guidelines ensuring the safe utilization of HTP.

E-cigarettes and arrhythmogenesis: a comprehensive review of pre-clinical studies and their clinical implications

Electronic cigarette use has grown exponentially in recent years, and while their popularity has increased, the long-term effects on the heart are yet to be fully studied and understood. Originally designed as devices to assist with those trying to quit traditional combustible cigarette use, their popularity has attracted use by teens and adolescents who traditionally have not smoked combustible cigarettes. Acute effects on the heart have been shown to be similar to traditional combustible cigarettes, including increased heart rate and blood pressure. The main components of electronic cigarettes that contribute to these arrhythmic effects are found in the e-liquid that is aerosolized and inhaled, comprised of nicotine, flavourings, and a combination of vegetable glycerin (VG) and propylene glycol (PG). Nicotine can potentially induce both ventricular and atrial arrhythmogenesis, with both the atrial and ventricular effects resulting from the interactions of nicotine and the catecholamines they release via potassium channels. Atrial arrhythmogenesis, more specifically atrial fibrillation, can also occur due to structural alterations, which happens because of nicotine downregulating microRNAs 133 and 590, both post-transcriptional growth factor repressors. Liquid flavourings and the combination of PG and VG can possibly lead to arrhythmic events by exposing users to acrolein, an aldehyde that stimulates TRPA1 that in turn causes a change towards sympathetic activation and autonomic imbalance. The design of these electronic delivery devices is constantly changing; therefore, it has proven extremely difficult to study the long-term effects on the heart caused by electronic cigarettes but will be important to understand given their rising popularity. The arrhythmic effects of electronic cigarettes appear similar to traditional cigarettes as well; however, a comprehensive review has not been compiled and is the focus of this article.

Electronic Cigarette Harms: Aggregate Evidence Shows Damage to Biological Systems

Evidence of the harms of e-cigarettes has been unfolding slowly and has been documented in many reviews and reports worldwide. A narrative review of new evidence is presented since, as research has continued, newly aggregated evidence of the dangers of electronic cigarettes on the brain, heart, and lungs is vital to inform decisions on restricting the use of e-cigarettes. Several biomedical research databases were searched for electronic cigarette health effects, emphasizing reviews, systematic reviews, and meta-analyses. Over 50 review studies, primarily in 2022 and 2023, illustrate some of the latest information on e-cigarette harms. Results show studies of respiratory, neurological, and cardiovascular effects. Researchers call for expanding studies through new methods to elaborate on initial findings of multiple harms emerging in clinical investigations. Since the use of electronic cigarettes for adult cessation is not sanctioned in most countries, it is clear that health authorities see significant costs to the health of the general population if the promotion and use of electronic cigarettes occur worldwide. Regulatory action to control electronic cigarettes should consider the substantial evidence of electronic cigarette harm.

Electronic nicotine delivery systems (ENDS): A convenient means of smoking?

Electronic nicotine delivery systems (ENDS), which are becoming increasingly popular in many parts of the world, have recently become more sophisticated in terms of their more active content and better controlled vaporisation. This review begins by describing how cigarette smoking led to the development of ENDS as a means of combatting nicotine addiction. ENDS are usually categorised as belonging to one of only three main generations, but a fourth has been added in order to differentiate the latest, most powerful, most advanced and innovative that have improved heating efficiency. Descriptions of the principal substances contained in ENDS are followed by considerations concerning the risk of toxicity due to the presence of albeit low concentrations of such a variety of compounds inhaled over a long time, and the increasingly widespread use of ENDS as a means of smoking illicit drugs. We also review the most widely used pharmacotherapeutic approaches to smoking cessation, and recent epidemiological data showing that ENDS can help some people to stop smoking. However, in order to ensure their appropriate regulation, there is a need for higher-quality evidence concerning the health effects and safety of ENDS, and their effectiveness in discouraging tobacco smoking.

The cardiovascular consequences of electronic cigarette smoking: a narrative review

INTRODUCTION

E-cigarettes have emerged as a popular alternative to traditional tobacco smoking in recent years. Despite their growing popularity, concerns have arisen regarding the cardiovascular implications of e-cigarette use.

AREAS COVERED

This narrative review aims to highlight the latest evidence on the impact of e-cigarettes on cardiovascular health.

EXPERT OPINION

Numerous studies have demonstrated that e-cigarette use can lead to acute adverse cardiovascular effects. Inhalation of e-cigarette aerosols exposes users to a wide range of potentially harmful substances that have been implicated in critical pathophysiologic pathways of cardiovascular disease, namely endothelial dysfunction, oxidative stress, inflammation, sympathetic overdrive, and arterial stiffness. While long-term epidemiological studies specifically focusing on the cardiovascular effects of e-cigarettes are still relatively scarce, early evidence suggests a potential association between e-cigarette use and an increased risk of adverse cardiovascular events. However, it is essential to recognize that e-cigarettes are relatively new products, and the full extent of their long-term cardiovascular impact has not been fully elucidated. In the meantime, promoting tobacco cessation strategies that are evidence-based and regulated, along with rigorous monitoring of e-cigarette use patterns and associated health outcomes, are essential steps in safeguarding cardiovascular health in the face of this emerging public health challenge.

Electronic cigarettes prolong ventricular repolarization in people who smoke tobacco cigarettes: implications for harm reduction

Electronic cigarettes are often used for smoking cessation as a harm reduction strategy, but studies comparing risks of electronic cigarettes (ECs) and tobacco cigarettes (TCs) are scarce. Ventricular repolarization in people who smoke TCs is abnormal. Baseline repolarization was compared among nonusers (people who do not use TCs or ECs) and people who use ECs or TCs. The acute effects of ECs and TCs on metrics of ventricular repolarization were then compared in people who chronically smoke. A total of 110 participants (59 female), including 35 people (21 females) in the TC cohort, 34 people (17 females) in the EC cohort, and 41 people (21 females) in the nonuser cohort, were included. None of the primary outcomes, Tpeak-end (Tp-e), Tp-e/QT, and Tp-e/QTc, were different among the three cohorts at supine baseline, even when adjusted for sex. When compared with the control exposure standing after acutely using the EC but not the TC, significantly prolonged all three primary indices of ventricular repolarization in people who smoke TCs. The major new finding in this study is that in people who smoke TCs, using an EC compared with a TC significantly prolongs ventricular repolarization. Furthermore, in our subgroup analysis by sex, this adverse effect on repolarization is found only in male, not female, smokers. In summary, chronic TC smoking is the most prevalent, modifiable risk factor for cardiovascular death, including sudden cardiac death. If used for smoking cessation, ECs should only be used in the short term since they too carry their own risks; this risk appears to be greatest in males compared with females who smoke.NEW & NOTEWORTHY The major new finding in this study is that in people who smoke tobacco cigarettes, using an electronic cigarette but not a tobacco cigarette acutely and significantly prolongs several metrics of ventricular repolarization, including Tpeak-Tend, Tpeak-Tend/QT, and Tpeak-Tend/QTc. Furthermore, in our subgroup analysis by sex, this adverse effect on repolarization is found only in male, not female, smokers.

Electronic Nicotine Delivery Systems and Cardiovascular/Cardiometabolic Health

The use of electronic nicotine delivery systems, specifically electronic cigarettes (e-cig), has risen dramatically within the last few years; the demographic purchasing these devices is now predominantly adolescents that are not trying to quit the use of traditional combustible cigarettes, but rather are new users. The composition and appearance of these devices has changed since their first entry into the market in the late 2000s, but they remain composed of a battery and aerosol delivery system that is used to deliver breakdown products of propylene glycol/vegetable glycerin, flavorings, and potentially nicotine or other additives. Manufacturers have also adjusted the type of nicotine that is used within the liquid to make the inhalation more palatable for younger users, further affecting the number of youth who use these devices. Although the full spectrum of cardiovascular and cardiometabolic consequences of e-cig use is not fully appreciated, data is beginning to show that e-cigs can cause both short- and long-term issues on cardiac function, vascular integrity and cardiometabolic issues. This review will provide an overview of the cardiovascular, cardiometabolic, and vascular implications of the use of e-cigs, and the potential short- and long-term health effects. A robust understanding of these effects is important in order to inform policy makers on the dangers of e-cigs use.

Cardiotoxicity of Electronic Cigarettes and Heat-Not-Burn Tobacco Products-A Problem for the Modern Pediatric Cardiologist

Electronic nicotine delivery systems (ENDS) have become increasingly popular among adolescents, either as an alternative to conventional cigarettes (CCs) or as a newly acquired recreational habit. Although considered by most users as a safer option for nicotine intake, these devices pose significant health risks, resulting in multisystem damage. Heat-not-burn products, which, unlike ENDS, contain tobacco, are also alternatives to CCs that consumers use based on the idea that their safety profile is superior to that of cigarettes. Recent studies in the USA and EU show that adolescents are particularly prone to using these devices. Pediatric cardiologists, as well as other healthcare professionals, should be aware of the complications that may arise from acute and chronic consumption of these substances, considering the cardiovascular damage they elicit. This article summarized the known data about the impact of ENDS on the cardiovascular system, with emphasis on the pathophysiological and molecular changes that herald the onset of systemic lesions alongside the clinical cardiovascular manifestations in this scenario.