Neurotoxicity of e-cigarettes

Impact of nicotine-free and nicotine-rich flavored electronic cigarette refill liquids on primary human melanocyte function

In this study, five popular EC liquid flavors-strawberry, banana, vanilla, tobacco, and menthol-were examined on human melanocyte functions. Each flavored e-liquid (in 80/20 PG/VG vehicle) was tested without or with 18 mg/mL nicotine. The effects of PG/VG and nicotine-containing vehicles were also evaluated. Results revealed that nicotine-free and nicotine-containing e-liquids had comparable cytotoxicity, with menthol> > banana> tobacco> vanilla> strawberry. This cytotoxicity was unrelated to either nicotine or the vehicle. PG/VG (1 and 2 %) increased melanin production without influencing cellular tyrosinase activity. The flavored e-liquids did not further affect melanin production, suggesting that the vehicle's effect, not the flavor, was responsible for the increased melanin production. Interestingly, nicotine at 2 % in the vehicle restored the stimulated melanin production to the control. Flavors suppressed cellular tyrosinase activity, with vanilla and banana flavors robustly inhibiting it. Vanilla and banana e-liquids also enhanced reactive oxygen species (ROS) production, which did not originate from the vehicle or nicotine-containing vehicle. Banana e-liquid with nicotine lowered ROS generation compared to nicotine-free banana e-liquid. Common flavors in e-liquids can cause cytotoxicity and influence melanogenesis even without nicotine, indicating that the use of ECs may not completely avoid the harmful effects of cigarette smoking. Further studies are warranted to investigate e-liquid aerosol effects on melanocytes.

World no-tobacco: effects of second-hand smoke (SHS) and vapors on the developing and adult brain

The goal of this review is to highlight the role of second-hand smoke (SHS) or environmental tobacco smoke (ETS) and e-cigarette (EC) vapors on brain integrity and function during development and adulthood, including how it relates to increasing the risk for age-related neurodegenerative disorders. A systematic review of the literature of the effect of SHS or ETS and e-cigarette vapors on the brain revealed a total of 284 or 372 publications and 312 publications, respectively. After taking into account duplicate publications or publications focused on policy, surveys or other organs than brain, there are limited studies on the effects of SHS, ETS or EC vapors on brain structure and function. In this review, we examine the major constituents in SHS or EC vapors and their effects on brain health, mechanisms by which SHS or vapors alters brain integrity and function, including behavioral and cognitive performance. We hope that this review will encourage investigators to explore further the short-as well long-term effects of SHS or vapor exposure on the developing and adult brain to better understand its role in neurodevelopmental disorders and neurodegenerative diseases and ultimately to develop therapeutic modalities to reduce or even prevent the short- and long-term detrimental effects on brain health.

Electronic cigarette use and heavy metal exposure: Evidence from the Korea National Health and Nutrition Examination Survey

PURPOSE

This study investigated the association between electronic cigarette (e-cigarette) use and serum concentrations of heavy metals (lead, mercury, and cadmium) in the Korean population, utilizing data from the Korea National Health and Nutrition Examination Survey (KNHANES), a nationally representative cross-sectional survey.

METHODS

Data from KNHANES 2013, 2016, and 2017 were analyzed. Participants were classified as e-cigarette users (individuals who had ever used e-cigarettes, including dual users who had also used conventional cigarettes), conventional smokers (individuals who had smoked at least 100 conventional cigarettes [5 packs], but not e-cigarettes, in their lifetime), and non-smokers (individuals who had never used e-cigarettes and either never smoked conventional cigarettes or smoked fewer than 100 cigarettes). Linear regression models were employed to evaluate the association between smoking status and heavy metal concentrations, adjusting for covariates including age, sex, income, education, and health behaviors. Subgroup analyses were performed based on sex, age, and obesity status.

RESULTS

E-cigarette users exhibited significantly higher serum concentrations of heavy metals than non-smokers. Lead levels were 10.0 % higher (exponentiated β = 1.100; p < 0.001), mercury levels were 13.7 % higher (β = 1.137; p < 0.001), and cadmium levels were 61.4 % higher (β = 1.614; p < 0.001). Conventional smokers demonstrated elevated levels of these metals compared to non-smokers, but generally lower levels than e-cigarette users. Subgroup analyses revealed stronger associations among younger participants, males, and individuals with obesity, particularly for cadmium.

CONCLUSIONS

Dual use of e-cigarettes and conventional cigarettes is associated with elevated exposure to heavy metals compared to exclusive smoking cigarettes. These findings highlight the need for targeted public health interventions and stricter regulatory standards to address the risks associated with e-cigarette use.

Electronic cigarettes: "wolves in sheep's clothing"

OBJECTIVE

To provide cutting-edge information on the impact and risks of using Electronic Nicotine Delivery Systems (ENDS) by children and adolescents, based on the latest evidence published in the literature.

DATA SOURCE

A comprehensive search was carried out on PubMed, using the expressions ''electronic cigarettes'' OR ''electronic nicotine delivery systems" OR "vaping" AND ''adolescent'' AND "risks" AND ''acute lung injury'. All retrieved articles had their titles and abstracts read to identify and fully read the papers reporting the most recent evidence on each subject.

SUMMARY OF FINDINGS

The use of ENDS has alarmingly increased in Brazil and around the world. The possibility of customizing use, the choice of flavors and nicotine content, and the general notion that these devices are harmless when compared to conventional cigarettes are some of the factors responsible for this increase. Numerous scientific studies have proven that electronic cigarettes have serious consequences for the respiratory system, such as EVALI (E-cigarette or Vaping-Associated Lung Injury) and difficult-to-control asthma, as well as harmful effects on the neurological, cardiovascular, gastrointestinal, and immunological systems. High concentrations of nicotine make many young people addicted to this substance. In Brazil, commercialization, import, and advertising are prohibited. The viable interventions to address the use of these devices in children and adolescents are prevention and behavioral counseling.

CONCLUSION

There is clear scientific evidence that these devices pose a risk to the physical and mental health of children and adolescents.

The use of the model organism Caenorhabditis elegans in the investigation of the adverse effects of electronic cigarettes

The use of tobacco products is one of the most preventable risk factors for mortality from a variety of diseases, including cardiovascular, infectious, respiratory, and neoplastic conditions. The use of electronic cigarettes (ECIGs), also known as electronic nicotine delivery devices, has increased significantly in recent years. Nicotine, propylene glycol, and / or glycerine, water, alcohol, flavorings, and other substances are among the many chemicals found in ECIGs that are vaporized and inhaled. A review of the existing literature shows that research dedicated to ECIGs is a rapidly developing and growing field of study. The rationale for the use of ECIGs is that they represent a safer alternative to traditional tobacco products. However, vaping safety profiles are still under development, as this is a relatively recent phenomenon. Various model organisms can be employed to examine the cellular processes that may be altered by exposure to the electronic liquids utilized for vaping. For example, the translucent multicellular eukaryote Caenorhabditis elegans is widely used as a model organism to explain a broad range of biological processes, including aging, stress response, development, and many others. Due to its short lifespan and easy use, C. elegans is an ideal model organism for studying chronic exposure to drugs and environmental toxicology. This review presents a summary of the most recent findings on the impact of electronic cigarettes on the physiological health of this nematode. Preliminary observations made in C. elegans can provide insight into the consequences of exposure to fundamental cellular physiology, which can then be used for future research in humans and mammalian models.

Assessing the Complex Impact of Smoking Habits on Allergic Rhinitis: A National Cross-Sectional Study

OBJECTIVES

Allergic rhinitis (AR) significantly impacts quality of life and incurs socioeconomic costs. The influence of smoking habits, including the use of conventional cigarettes (CCs) and electronic cigarettes (ECs), on the prevalence and management of AR remains a subject of debate. This study aims to explore the association between smoking status (CC and EC use) and the prevalence and management of AR among Koreans by analyzing data from the Korea National Health and Nutrition Examination Survey (KNHANES) VII (2018) and VIII (2019-2021).

METHODS

This cross-sectional study involved 22,290 participants aged 19 years and older from the KNHANES. Participants self-reported their smoking status, and urinary cotinine levels were measured to assess nicotine exposure. We employed statistical analyses, including logistic regression, to examine the relationships between smoking status, cotinine levels, and the prevalence and management of AR.

RESULTS

In univariable logistic regression analysis, EC users exhibited a 35.8% increased risk of AR compared to non-smokers, whereas CC users experienced a 27.7% reduced risk. Multivariable logistic regression analysis showed a 20.3% lower risk of AR among CC users; however, no significant association was observed for EC users. Higher cotinine levels (>500 ng/mL) were associated with a lower prevalence of AR. Specifically, heavy CC users with high cotinine levels demonstrated a 35% reduced risk of AR. Nonetheless, after adjusting for confounders, this association was no longer significant, indicating that other variables might influence this relationship.

CONCLUSION

Smoking status is associated with the prevalence of AR in Koreans. Notably, heavy use of CCs is negatively correlated with the prevalence of AR.

Role of Glial Cells and Receptors in Schizophrenia Pathogenesis

The specific pathogeneses of schizophrenia (SCZ) remain an enigma despite extensive research that has implicated both genetic and environmental factors. Recent revelations that dysregulated immune system caused by glial cell overactivation result in neuroinflammation, a key player in neurodegenerative as well as neuropsychiatric disorders including SCZ are providing novel clues on potential therapeutic interventions. Here, we review the roles of glial cells (Dr. Arne Schousboe's passion) and two of their most implicated receptors, toll-like receptors (TLRs), and nicotinic cholinergic receptors, in SCZ pathology with suggestions as potential targets in this devastating neuropsychiatric condition.

Lush Ice High: A Rare Case of Nicotine E-Liquid-Induced Toxic Encephalopathy

E-cigarette consumption has increased globally, partly due to its perceived role as a harm-reduction alternative to conventional cigarettes. It has been linked to various neurotoxic pathologies including stroke, cognitive dysfunction, and neurodevelopmental disorders. Acute e-liquid intoxication can lead to a fatal syndrome of respiratory failure, cardiovascular instability, acute encephalopathy, and gastrointestinal distress. We present a case of toxic encephalopathy due to e-liquid intoxication directly from an e-cigarette device. Our patient is a 59-year-old man who presented to the hospital with signs of tachycardia, tremors, paranoia, disorientation, hypervigilance, physical hostility, and aphasic mutism, was unable to provide any history, and was treated on suspicion of acute encephalopathy and possible delirium tremens. Imaging including CT brain and chest X-ray was unremarkable. Laboratory tests were significant for leukocytosis (16.4 x 103/mcL), hypernatremia (157 mmol/L), acute kidney injury (blood urea nitrogen (BUN) 26 mg/dL, creatinine 1.70 mg/dL), anion gap metabolic acidosis (18 mEq/L), and urine toxicology screen positive for cocaine and benzodiazepines. He was thereafter managed in the intensive care unit for close monitoring with an uncomplicated course. On the second day, he was found to be awake, alert, oriented, and without any focal neurological deficits. The patient claimed that prior to the emergency room (ER) visit, he orally consumed 4 mL of e-liquid from a 5% nicotine e-cigarette pen through an opening in the device. Serum analysis was significant for cotinine concentration of 30 ng/mL (primary metabolite of nicotine) and nicotine concentration of 2 ng/mL. No symptomatic sequelae were reported for the rest of the hospital course, and the patient was discharged on the fourth day after laboratory tests showed a resolution of earlier findings. This case of moderate e-liquid intoxication showed acute encephalopathy with resolution significantly different from the classically described biphasic pattern of nicotine intoxication-an initial stimulatory syndrome of nausea, hypertension, tachycardia, tremor, and seizures followed by depressor symptoms including hypotension, bradycardia, weakness, and CNS and respiratory depression. The neurotoxic effects of nicotine and non-nicotinic substances in e-cigarettes need to be investigated further to develop standardized management guidelines for acute e-liquid intoxication.

Shaping the Future: Proposed Bills to Regulate New and Emerging Tobacco and Nicotine Products in Latin America and the Caribbean Amidst Public Health Concerns and Industry Interests

INTRODUCTION

To examine legislative efforts to regulate new and emerging tobacco and nicotine products (NETNPs) in Latin America and the Caribbean (LAC) between 2017 and 2022.

AIMS AND METHODS

Analysis of online national legislation databases to track NETNP bills using standard snowball search methods.

RESULTS

Bills were identified in 15 out of the 33 LAC countries, accounting for a total of 91 bills targeting NETNPs. Mexico had the highest number (n = 38) of bills, followed by Brazil (n = 16), Argentina (n = 10), Colombia (n = 8), and Chile (n = 5). The remaining countries introduced two or fewer NETNP bills. Among the identified 91 bills, the majority (n = 60) addressed both electronic cigarettes and heated tobacco products (HTPs), almost one-third of bills (n = 29) applied only to electronic cigarettes, and only two focused solely on HTPs. Six of the fifteen countries with identified bills, enacted one NETNP law including Barbados, Bolivia, Costa Rica, Guyana, Mexico, and Panama. Since 2019, there has been a steady increase in the amount of NETNP bills introduced in LAC. In 2017 and 2018, 10 NETNP bills were introduced each year followed by 23 NETNP bills introduced in each 2019 and 2020, 19 in 2021, and 16 by August 2022.

CONCLUSIONS

The substantial increase in the number of NETNP bills introduced since 2019 indicates the growing importance of regulating NETNPs in LAC. As NETNPs continue to evolve and grow it is important to continue monitoring and evaluating tobacco and nicotine regulatory initiatives while also staying ahead of the evolving market of NETNPs.

IMPLICATIONS

Previous studies have analyzed the regulatory environment of NETNPs but it is less known about legislative and regulatory efforts and attempts. This is the first known study to analyze legislative bills to regulate NETNPs in Latin America and the Caribbean (LAC). The substantial increase in the number of NETNP bills introduced in LAC since 2019 indicates the growing importance of regulating NETNPs in LAC. As NETNPs continue to evolve and grow it is important to continue monitoring and evaluating tobacco and nicotine regulatory initiatives while also staying ahead of the evolving market of NETNPs.

Psychosocial stressors of adolescents with E-cigarette, or vaping, product-use associated lung injury: A qualitative study

BACKGROUND AND OBJECTIVES

Adolescent electronic cigarette (EC) use has reached epidemic rates and has been linked to numerous mental health and psychosocial stressors (PS). There is limited qualitative data on PS for adolescents with e-cigarette, or vaping, product-use associated lung injury (EVALI), a severe complication of EC use.

METHODS

All patients hospitalized at Children's Medical Center in Dallas, Texas from 2018 to 2022 and met CDC case definitions for EVALI were included in the analysis. PS were extracted from the electronic health record and analyzed for recurring themes using the HEADSS assessment as a framework. Results were summarized using descriptive statistics, and representative quotations were selected to highlight each theme.

RESULTS

Forty-three adolescents (mean age 16.3 years; 62.8 % male; 39.5 % Non-Hispanic White, 60.5 % Hispanic) were included in the analysis, and 40 (93 %) reported PS. The most common themes were family (51 %; "restraining order issued against 28-year-old brother"), polysubstance use (77 %; "experimenting with…ecstasy, LSD, CCC, misusing Adderall"), and mental health (63 %; "has been suicidal since he was 'a toddler'"). Less commonly, patients reported PS related to peers (28 %; "spending the entire day at the cemetery where his best friend was buried"), school (49 %; "attending his second alternative school"), and the legal system (19 %; "placed in juvenile detention, released, and will be on probation").

CONCLUSIONS

Adolescents with EVALI had PS that were chronic, severe, and involving multiple domains. These findings emphasize the importance of psychosocial screening in adolescents and coordinating interdisciplinary care with mental health and social services.

In Utero Exposure to Maternal Electronic Nicotine Delivery System use Demonstrate Alterations to Craniofacial Development

OBJECTIVE

Develop a model for the study of Electronic Nicotine Device (ENDS) exposure on craniofacial development.

DESIGN

Experimental preclinical design followed as pregnant murine dams were randomized and exposed to filtered air exposure, carrier exposure consisting of 50% volume of propylene glycol and vegetable glycine (ENDS Carrier) respectively, or carrier exposure with 20 mg/ml of nicotine added to the liquid vaporizer (ENDS carrier with nicotine).

SETTING

Preclinical murine model exposure using the SciReq exposure system.

PARTICIPANTS

C57BL6 adult 8 week old female pregnant mice and exposed in utero litters.

INTERVENTIONS

Exposure to control filtered air, ENDS carrier or ENDS carrier with nicotine added throughout gestation at 1 puff/minute, 4 h/day, five days a week.

MAIN OUTCOME MEASURES

Cephalometric measures of post-natal day 15 pups born as exposed litters.

RESULTS

Data suggests alterations to several facial morphology parameters in the developing offspring, suggesting electronic nicotine device systems may alter facial growth if used during pregnancy.

CONCLUSIONS

Future research should concentrate on varied formulations and exposure regimens of ENDS to determine timing windows of exposures and ENDS formulations that may be harmful to craniofacial development.

Investigative analysis of blood-brain barrier penetrating potential of electronic nicotine delivery systems (e-cigarettes) chemicals using predictive computational models

INTRODUCTION

Seizures are known potential side effects of nicotine toxicity and have been reported in electronic nicotine delivery systems (ENDS, e-cigarettes) users, with the majority involving youth or young adults.

AREAS COVERED

Using chemoinformatic computational models, chemicals (including flavors) documented to be present in ENDS were compared to known neuroactive compounds to predict the blood-brain barrier (BBB) penetration potential, central nervous system (CNS) activity, and their structural similarities. The literature search used PubMed/Google Scholar, through September 2023, to identify individual chemicals in ENDS and neuroactive compounds.The results show that ENDS chemicals in this study contain >60% structural similarity to neuroactive compounds based on chemical fingerprint similarity analyses. The majority of ENDS chemicals we studied were predicted to cross the BBB, with approximately 60% confidence, and were also predicted to have CNS activity; those not predicted to passively diffuse through the BBB may be actively transported through the BBB to elicit CNS impacts, although it is currently unknown.

EXPERT OPINION

In lieu of in vitro and in vivo testing, this study screens ENDS chemicals for potential CNS activity and predicts BBB penetration potential using computer-based models, allowing for prioritization for further study and potential early identification of CNS toxicity.

E-cigarette use or dual use of E-cigarette and combustible cigarette and mental health and cognitive impairment: Findings from the National Health Interview Survey, 2020-2021

BACKGROUND

Studies on the association between e-cigarette use and mental health are mostly among adolescents and young adults, leaving limited evidence of this association among general US adults. Besides, few studies have examined how e-cigarette use or dual use of e-cigarette and combustible cigarette is related to cognitive function.

METHODS

Cross-sectional data of 56,734 adults from the 2020-2021 National Health Interview Survey were analyzed. Weighted multivariable logistic regression models were applied to examine the independent association between e-cigarette use or dual use and anxiety symptoms, depression symptoms, serious psychological distress (SPD), and cognitive impairment.

RESULTS

Compared with never e-cigarette users, current e-cigarette users had 2.10-fold (95 % CI: 1.84, 2.39), 2.53-fold (95 % CI: 2.13, 3.00), 2.02-fold (95 % CI: 1.47, 2.76), and 2.00-fold (95 % CI: 1.47, 2.72) higher odds of reporting anxiety symptoms, depression symptoms, SPD, and cognitive impairment, respectively. Former e-cigarette use was also associated with all three mental conditions and cognitive impairment (AOR ranged from 1.38 to 2.53, all P < 0.01). Dual users were more likely to report all three mental conditions and cognitive impairment than those who never used combustible cigarette and e-cigarette (AOR ranged from 1.89 to 2.83, all P < 0.01). Dual users also had a greater likelihood of having anxiety or depression symptoms than exclusive combustible cigarette users (AOR ranged from 1.46 to 1.47, all P < 0.01).

CONCLUSIONS

E-cigarette use or dual use is associated with poor mental health and cognitive impairment among US adults. Regulations on e-cigarette use are needed to prevent mental illness and improve cognitive function.

E-Cigarette Exposure Alters Neuroinflammation Gene and Protein Expression in a Murine Model: Insights from Perinatally Exposed Offspring and Post-Birth Mothers

The use of E-cigarettes, often considered a safer alternative to traditional smoking, has been associated with high rates of cellular toxicity, genetic alterations, and inflammation. Neuroinflammatory impacts of cigarette smoking during pregnancy have been associated with increased risks of adverse childhood health outcomes; however, it is still relatively unknown if the same propensity is conferred on offspring by maternal vaping during gestation. Results from our previous mouse inhalation studies suggest such a connection. In this earlier study, pregnant C57BL/6 mice were exposed daily to inhaled E-cig aerosols (i.e., propylene glycol and vegetable glycerin, [PG/VG]), with or without nicotine (16 mg/mL) by whole-body inhalation throughout gestation (3 h/d; 5 d/week; total ~3-week) and continuing postnatally from post-natal day (PND) 4-21. As neuroinflammation is involved in the dysregulation of glucose homeostasis and weight gain, this study aimed to explore genes associated with these pathways in 1-mo.-old offspring (equivalent in humans to 12-18 years of age). Results in the offspring demonstrated a significant increase in glucose metabolism protein levels in both treatment groups compared to filtered air controls. Gene expression analysis in the hypothalamus of 1 mo. old offspring exposed perinatally to E-cig aerosols, with and without nicotine, revealed significantly increased gene expression changes in multiple genes associated with neuroinflammation. In a second proof-of-principal parallel study employing the same experimental design, we shifted our focus to the hippocampus of the postpartum mothers. We targeted the mRNA levels of several neurotrophic factors (NTFs) indicative of neuroinflammation. While there were suggestive changes in mRNA expression in this study, levels failed to reach statistical significance. These studies highlight the need for ongoing research on E-cig-induced alterations in neuroinflammatory pathways.

Zebrafish (Danio rerio) as a Model for the Study of Developmental and Cardiovascular Toxicity of Electronic Cigarettes

The increasing popularity of electronic cigarettes (e-cigarettes) as an alternative to conventional tobacco products has raised concerns regarding their potential adverse effects. The cardiovascular system undergoes intricate processes forming the heart and blood vessels during fetal development. However, the precise impact of e-cigarette smoke and aerosols on these delicate developmental processes remains elusive. Previous studies have revealed changes in gene expression patterns, disruptions in cellular signaling pathways, and increased oxidative stress resulting from e-cigarette exposure. These findings indicate the potential for e-cigarettes to cause developmental and cardiovascular harm. This comprehensive review article discusses various aspects of electronic cigarette use, emphasizing the relevance of cardiovascular studies in Zebrafish for understanding the risks to human health. It also highlights novel experimental approaches and technologies while addressing their inherent challenges and limitations.

A literature review addressing midwakh and e-cigarette use in the Gulf region

A notable decrease in conventional cigarette smoking has been witnessed on a global scale. However, this decrease has been accompanied by an equally striking global increase in the consumption of alternative tobacco products (ATPs), namely e-cigarettes and midwakh in the Arabian Gulf region. A literature review was used to outline the chemical composition of these two ATPs and review their impacts on health. The study was conducted using databases like PubMed, Google Scholar, MDPI, and WorldCat. The literature search included terms such as "e-cigarettes," "midwakh," "dokha," "heath impacts," "psychological effects," "social influences," and "cigarette smoking" with emphasis on literature from the Arabian Gulf region. Data shows that midwakh contains markedly high levels of tar, nicotine, and various compounds of notable effects on the human body. Similarly, it was found that e-cigarettes contain non-negligible amounts of nicotine and other chemical compounds that may not have been extensively investigated. Alarming reports of system-specific effects brought about by midwakh, and e-cigarette consumption, have been reported, although further research is needed to deduce the mechanism. We also discussed some of the social and psychological factors leading to their consumption within this population. Hence, this review raises questions around the safety of these two types of ATPs and encourages comprehensive studies globally and regionally.

The effectiveness of an intervention to reduce exposure to trace metals during or prior to pregnancy: A prospective study in urban and rural locations

Background

Prenatal exposure to trace metals can have adverse effects on health and increase the risk of developing certain diseases. This study aimed to determine the effectiveness of giving women advice to reduce their exposure to trace metals during pregnancy or prior to conception. The study also examined differences in exposure between rural and urban environments in southern France.

Methods

In this prospective study, pregnant women or those intending to conceive were recruited from two medical centers for gynecology/obstetrics (rural location: Saint-Rémy-de-Provence; urban location: Marseille). Hair samples were collected and analyzed to determine the levels of exposure to trace metals. Participants with 'risky' levels were given corresponding advice sheets on how to reduce their exposure or, for certain metals, they were encouraged to find out about potential sources of exposure. A second hair sample was collected and analyzed 3 months later.

Results

It was found that 109 women had 'risky' levels of exposure to trace metals, out of a total of 184 women (59.2 %). Cerium was the most frequently identified metal (N = 26), followed by nickel (N = 23), and titanium (N = 19). There were more women at the urban center with 'risky' levels (56/86; 65.1 %) than at the rural center (53/98; 54.1 %), but this difference was not statistically significant (p = 0.13). Advice sheets were given to 64 of the 109 participants with 'risky' levels (58.7 %), but only 21 returned for the second hair analysis. Of these, 14 were found to have reduced their exposure, which corresponds to just 12.8 % (14/109) of the participants with 'risky' levels.

Conclusions

These results indicate that it would be helpful to develop new interventions to reduce trace metal exposure during or prior to pregnancy.

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.

Impact of e-cigarette liquid on porcine lung tissue-Ex vivo confocal Raman micro-spectroscopy study

Ex vivo porcine lung immersed in e-liquid was investigated in-depth using confocal Raman micro-spectroscopy to assess the e-liquid influence on the lung. It was found that lung-related Raman band intensities at 1002, 1548, 1618 and 1655 cm-1 increased after first and second treatments except the surface, which was attributed to the well-known optical clearing (OC) effect due to alveoli filling with e-liquid resulting in light scattering reduction. The autofluorescence enhancement was explained by oxidative stress induced in lung during exposure to e-liquid. Moreover, e-liquid induced collagen dehydration was revealed by the I937 /I926 Raman band intensity ratio change. The effect was enhanced after the second treatment of the same lung tissue that indicates the possibility of multi-step OC treatment. We hypothesize that the nicotine-flavour-free e-liquids containing glycerol and propylene glycol could potentially be used in clinical protocols as OC agent for enhanced in-depth Raman-guided bronchoscopy.

Association between metal exposure from e-cigarette components and toxicity endpoints: A literature review

Electronic cigarette is often promoted and perceived as an 'healthy' alternative compared to conventional cigarettes. However, growing body of evidence indicate the possible adverse health effect associated with e-cigarette. Here we reviewed the literature with a focus on metal exposure in relation to e-cigarette use and related toxicity endpoints. Twenty-nine studies were identified for full text screening after applying the screening criteria of which 5 in vitro studies and 11 epidemiological studies were included for data extraction. Cr, Cu, Ni, Sn are the most found metal in all studies. In vitro, metal from e-cigarette (liquid or aerosols) induced cytotoxicity, oxidative stress, genotoxicity and pro-inflammatory responses. It was observed that the presence of nicotine can influence metal-induced in vitro toxicity. Based on epidemiological studies, the metal burden in e-cigarette users showed to be elevated in different populations (including e.g. NHANES). However, most often such studies were limited by the missing user characteristics, and information of other potential sources of metal exposure. In general, metals from e-cigarette use can be associated with toxicity endpoints but to uncover the metal related hazard of e-cigarette in users, more detailed data on metals in vapors and e-liquids; user habits and user demographics are needed.

Nicotine neurotoxicity exacerbation following engineered Ag and Cu (50-60 nm) nanoparticles intoxication. Neuroprotection with nanowired delivery of antioxidant compound H-290/51 together with serotonin 5-HT3 receptor antagonist ondansetron

Nicotine abuse is frequent worldwide leading to about 8 millions people die every year due to tobacco related diseases. Military personnel often use nicotine smoking that is about 12.8% higher than civilian populations. Nicotine smoking triggers oxidative stress and are linked to several neurodegenerative diseases such as Alzheimer's disease. Nicotine neurotoxicity induces significant depression and oxidative stress in the brain leading to neurovascular damages and brain pathology. Thus, details of nicotine neurotoxicity and factors influencing them require additional investigations. In this review, effects of engineered nanoparticles from metals Ag and Cu (50-60 nm) on nicotine neurotoxicity are discussed with regard to nicotine smoking. Military personnel often work in the environment where chances of nanoparticles exposure are quite common. In our earlier studies, we have shown that nanoparticles alone induces breakdown of the blood-brain barrier (BBB) and exacerbates brain pathology in animal models. In present investigation, nicotine exposure in with Ag or Cu nanoparticles intoxicated group exacerbated BBB breakdown, induce oxidative stress and aggravate brain pathology. Treatment with nanowired H-290/51 a potent chain-breaking antioxidant together with nanowired ondansetron, a potent 5-HT3 receptor antagonist significantly reduced oxidative stress, BBB breakdown and brain pathology in nicotine exposure associated with Ag or Cu nanoparticles intoxication. The functional significance of this findings and possible mechanisms of nicotine neurotoxicity are discussed based on current literature.

Preliminary study on the E-liquid and aerosol on the neurobehavior of C. elegans

E-cigarettes, also known as electronic nicotine delivery systems (ENDS), are mainly used among adolescents and young adults. Similar to traditional cigarettes, different concentrations of nicotine are also added to E-cigarette's liquid (E-liquid), but due to the supplementation of chemicals such as propylene glycol (PG), vegetable glycerin (VG) and flavors, it is difficult to determine the risk after using E-cigarettes. And given to the specificity of the aerosol particle composition and atomization process of E-cigarettes, it is necessary to assess the neurotoxic effects of long-term E-cigarettes use. In this study, two commercial nicotine-containing (5%) and nicotine-free E-liquids were diluted to investigate the neurobehavioral changes and addictive tendencies of developing C. elegans after sub-chronic exposure to E-liquid. The results showed that sub-chronic exposure of E-liquid could lead to impaired growth and development of nematodes, abnormal general neuromotor behavior and advanced learning and memory behavior, and nicotine-containing E-liquid could also lead to increased addiction tendency of nematodes. Although the damage effect of nicotine free E-liquid is smaller than that of the nicotine-containing group, its toxic effect cannot be ignored. Further analysis of the neurotoxicity mechanism found that redox imbalance-mediated mitochondrial stress and aging may be important causes of E-liquid-induced biological damage. The biosafety of e-cigarette aerosols was also included in the assessment. The study found that the heated atomization process did not alter the E-liquid components, and E-cigarette aerosols still have the effect of interfering with the growth and development of nematodes and neurobehavior, and its addictive nature is also of concern. This study can provide new ideas for future studies on the neurotoxic effects and safety assessment of the E-cigarettes, and provide theoretical reference for the study on the injury mechanism of E-cigarettes.

New tobacco and nicotine products in Latin America and the Caribbean: assessing the market and regulatory environment

OBJECTIVE

To document the regulatory environment of new tobacco and nicotine products (NTNPs), including electronic nicotine delivery systems (ENDS) and heated tobacco products (HTPs), in Latin America and the Caribbean (LAC).

METHODS

Review of market research reports and databases, regulatory websites, Campaign for Tobacco-Free Kids, relevant published literature and the 2021 WHO Report on the Global Tobacco Epidemic.

RESULTS

ENDS entered the LAC market in the 2010s and are now available in most LAC countries. A majority of LAC countries (n=18) have either banned the commercialisation of ENDS (n=7) or regulated ENDS as tobacco products (n=7), medicinal products (n=1) or consumer products (n=3). The remaining LAC countries (n=15) do not regulate ENDS. HTPs were first introduced in 2017 and have been officially launched in five countries (Colombia, Guatemala, Dominican Republic, Mexico and Costa Rica). Few countries have banned HTP commercialisation (n=3) or regulated commercialisation and use (n=7), while the majority of countries have existing legislation that applies to HTPs (n=19). A few countries (n=4) have no tobacco control legislation and therefore do not regulate HTPs.

CONCLUSION

NTNPs are emerging products in the LAC region. Governments should follow WHO guidance and the decisions of the Conference of Parties to the WHO Framework Convention on Tobacco Control and ban or regulate NTNPs as tobacco products; otherwise NTNPs could create a new generation of tobacco and nicotine users.

The impact of e-cigarette exposure on different organ systems: A review of recent evidence and future perspectives

The use of electronic cigarettes (e-cigs) is rapidly increasing worldwide and is promoted as a smoking cessation tool. The impact of traditional cigs on human health has been well-defined in both animal and human studies. In contrast, little is known about the adverse effects of e-cigs exposure on human health. This review summarizes the impact of e-cigs exposure on different organ systems based on the rapidly expanding recent evidence from experimental and human studies. A number of growing studies have shown the adverse effects of e-cigs exposure on various organ systems. The summarized data in this review indicate that while e-cigs use causes less adverse effects on different organs compared to traditional cigs, its long-term exposure may lead to serious health effects. Data on short-term organ effects are limited and there is no sufficient evidence on long-term organ effects. Moreover, the adverse effects of secondhand and third hand e-cigs vapour exposure have not been thoroughly investigated in previous studies. Although some studies demonstrated e-cigs used as a smoking cessation tool, there is a lack of strong evidence to support it. While some researchers suggested e-cigs as a safer alternative to tobacco smoking, their long-term exposure health effects remain largely unknown. Therefore, more epidemiological and prospective studies including mechanistic studies are needed to address the potential adverse health effects of e-cigs to draw a firm conclusion about their safe use. A wide variation in e-cigs products and the lack of standardized testing methods are the major barriers to evaluating the existing data. Specific regulatory guidelines for both e-cigs components and the manufacturing process may be effective to protect consumer health.

Maternal e-cigarette use can disrupt postnatal blood-brain barrier (BBB) integrity and deteriorates motor, learning and memory function: influence of sex and age

Electronic nicotine delivery systems (ENDS), also commonly known as electronic cigarettes (e-cigs) are considered in most cases as a safer alternative to tobacco smoking and therefore have become extremely popular among all age groups and sex. It is estimated that up to 15% of pregnant women are now using e-cigs in the US which keeps increasing at an alarming rate. Harmful effects of tobacco smoking during pregnancy are well documented for both pregnancy and postnatal health, however limited preclinical and clinical studies exist to evaluate the long-term effects of prenatal e-cig exposure on postnatal health. Therefore, the aim of our study is to evaluate the effect of maternal e-cig use on postnatal blood-brain barrier (BBB) integrity and behavioral outcomes of mice of varying age and sex. In this study, pregnant CD1 mice (E5) were exposed to e-Cig vapor (2.4% nicotine) until postnatal day (PD) 7. Weight of the offspring was measured at PD0, PD7, PD15, PD30, PD45, PD60 and PD90. The expression of structural elements of the BBB, tight junction proteins (ZO-1, claudin-5, occludin), astrocytes (GFAP), pericytes (PDGFRβ) and the basement membrane (laminin α1, laminin α4), neuron specific marker (NeuN), water channel protein (AQP4) and glucose transporter (GLUT1) were analyzed in both male and female offspring using western blot and immunofluorescence. Estrous cycle was recorded by vaginal cytology method. Long-term motor and cognitive functions were evaluated using open field test (OFT), novel object recognition test (NORT) and morris water maze test (MWMT) at adolescence (PD 40-45) and adult (PD 90-95) age. In our study, significantly reduced expression of tight junction proteins and astrocyte marker were observed in male and female offspring until PD 90 (P < 0.05). Additionally, prenatally e-cig exposed adolescent and adult offspring showed impaired locomotor, learning, and memory function compared to control offspring (P < 0.05). Our findings suggest that prenatal e-cig exposure induces long-term neurovascular changes of neonates by disrupting postnatal BBB integrity and worsening behavioral outcomes.

Tobacco-Free Oral Nicotine Product Use Among Youth in the U.S., 2019-2021

Introduction

Novel tobacco-free oral nicotine products are not combusted, easy to conceal, available in flavors, and do not contain tobacco leaf. Since 2016, oral nicotine product sales have increased and may be gaining popularity among youth. This study aims to examine the trends in the prevalence and correlates of oral nicotine product use among U.S. youth.

Methods

Data from participants aged 16-19 years in the U.S. International Tobacco Control Policy Evaluation Project Youth Tobacco and Vaping Survey were analyzed cross-sectionally from August 2019, February 2020, August 2020, February 2021, and August 2021. Weighted descriptive statistics and logistic regressions were used to describe the use and correlates of oral nicotine products.

Results

Oral nicotine product use significantly increased from 3.5% in August 2019 to 4.1% in August 2021. Oral nicotine product use was most prevalent among those aged 18 years, male, and non-Hispanic White. Those who used cigarettes (AOR=2.18, 95% CI=19.37, 40.88), nicotine vaping products (AOR=4.27, 95% CI=3.02, 6.04), and smokeless tobacco (AOR=28.14, 95% CI=19.37, 40.88) in the past 30 days were more likely to report recent use of oral nicotine products.

Conclusions

Although oral nicotine products are less popular among U.S. youth than cigarettes, nicotine vaping products, and smokeless tobacco, their prevalence of use significantly increased. Oral nicotine product users are more likely to use other nicotine products, but the availability of flavors and easy-to-conceal design may be appealing to those who may not use nicotine products. Researchers should continue to observe the behaviors associated with oral nicotine product use to inform the need for future regulatory efforts.

Influence of puff topographies on e-liquid heating temperature, emission characteristics and modeled lung deposition of Puff Bar™

Puff Bar™, one of the latest designs of e-cigarettes, heats a mixture of liquid using a battery-powered coil at certain temperatures to emit aerosol. This study presents a mass-based characterization of emissions from seven flavors of Puff Bar™ devices by aerosolizing with three puff topographies [(puff volume: 55 < 65 < 75-mL) within 4-seconds at 30-seconds interval]. We evaluated the effects of puff topographies on heating temperatures; characterized particles using a cascade impactor; and measured volatile carbonyl compounds (VCCs). Modeled dosimetry and calculated mass median aerodynamic diameters (MMADs) were used to estimate regional, total respiratory deposition of the inhaled aerosol and exhaled fractions that could pose secondhand exposure risk. Temperatures of Puff Bar™ e-liquids increased with increasing puff volumes: 55mL (116.6 °C), 65 mL (128.3 °C), and 75mL (168.9 °C). Flavor types significantly influenced MMADs, total mass of particles, and VCCs (μg/puff: 2.15-2.30) in Puff Bar™ emissions (p < 0.05). Increasing puff volume (mL:55 < 65 < 75) significantly increased total mass (mg/puff: 4.6 < 5.6 < 6.2) of particles without substantially changing MMADs (~1μm:1.02~0.99~0.98). Aerosol emissions were estimated to deposit in the pulmonary region of e-cigarette user (41-44%), which could have toxicological importance. More than 2/3 (67-77%) of inhaled particles were estimated to be exhaled by users, which could affect bystanders. The VCCs measured contained carcinogens-formaldehyde (29.6%) and acetaldehyde (16.4%)-as well as respiratory irritants: acetone (23.9%), isovaleraldehyde (14.5%), and acrolein (4.9%). As Puff Bar™ emissions contain respirable particles and harmful chemicals, efforts should be made to minimize exposures, especially in indoor settings where people (including vulnerable populations) spend most of their life-time.

Disruption of the Molecular Regulation of Mitochondrial Metabolism in Airway and Lung Epithelial Cells by Cigarette Smoke: Are Aldehydes the Culprit?

Chronic obstructive pulmonary disease (COPD) is a devastating lung disease for which cigarette smoking is the main risk factor. Acetaldehyde, acrolein, and formaldehyde are short-chain aldehydes known to be formed during pyrolysis and combustion of tobacco and have been linked to respiratory toxicity. Mitochondrial dysfunction is suggested to be mechanistically and causally involved in the pathogenesis of smoking-associated lung diseases such as COPD. Cigarette smoke (CS) has been shown to impair the molecular regulation of mitochondrial metabolism and content in epithelial cells of the airways and lungs. Although it is unknown which specific chemicals present in CS are responsible for this, it has been suggested that aldehydes may be involved. Therefore, it has been proposed by the World Health Organization to regulate aldehydes in commercially-available cigarettes. In this review, we comprehensively describe and discuss the impact of acetaldehyde, acrolein, and formaldehyde on mitochondrial function and content and the molecular pathways controlling this (biogenesis versus mitophagy) in epithelial cells of the airways and lungs. In addition, potential therapeutic applications targeting (aldehyde-induced) mitochondrial dysfunction, as well as regulatory implications, and the necessary required future studies to provide scientific support for this regulation, have been covered in this review.

Recognising the importance of chronic lung disease: a consensus statement from the Global Alliance for Chronic Diseases (Lung Diseases group)

BACKGROUND

Chronic respiratory diseases are disorders of the airways and other structures of the lung, and include chronic obstructive pulmonary disease (COPD), lung cancer, asthma, bronchiectasis, interstitial lung diseases, occupational lung diseases and pulmonary hypertension. Through this article we take a broad view of chronic lung disease while highlighting (1) the complex interactions of lung diseases with environmental factors (e.g. climate change, smoking and vaping) and multimorbidity and (2) proposed areas to strengthen for better global patient outcomes.

CONCLUSION

We suggest new directions for the research agenda in high-priority populations and those experiencing health disparities. We call for lung disease to be made a research priority with greater funding allocation globally.

Impact of Electronic Cigarettes on the Upper Aerodigestive Tract: A Comprehensive Review for Otolaryngology Providers

Objective

The use and effects of electronic (e)-cigarettes (e-cigs) are particularly relevant for otolaryngology providers as tobacco plays a major role in benign and malignant diseases of the upper aerodigestive tract. This review aims to (1) summarize the recent policies regarding e-cigs and important patterns of use and (2) serve as a comprehensive resource for clinical providers on the known biologic and clinical effects of e-cigs on the upper aerodigestive tract.

Data Sources

PubMed/MEDLINE.

Review Methods

We conducted a narrative review on (1) general information on e-cig use and informative findings in the lower respiratory system and a comprehensive review on (2) the effects of e-cigs on cell and animal models and the clinical implications of these products on human health as is relevant to otolaryngology.

Conclusions

Although e-cigs are likely less harmful than conventional cigarettes, preliminary research on e-cigs suggest several deleterious effects including in the upper aerodigestive tract. Due to this, there has been increased interest in restricting e-cig usage, particularly among the adolescent population, and caution in recommending e-cigs to current smokers.

Implications for Practice

Chronic e-cig use is likely to have clinical implications. It is critical for otolaryngology providers to be aware of the rapidly changing regulations and use patterns regarding e-cigs and how e-cigs influence human health, particularly with regards to the upper aerodigestive tract, to accurately council patients regarding potential risks and benefits of use.

E-cigarette Flavors, Sensory Perception, and Evoked Responses

The chemosensory experiences evoked by flavors encompass a number of unique sensations that include olfactory stimuli (smell), gustatory stimuli (taste, i.e., salty, sweet, sour, bitter, and umami (also known as "savoriness")), and chemesthesis (touch). As such, the responses evoked by flavors are complex and, as briefly stated above, involve multiple perceptive mechanisms. The practice of adding flavorings to tobacco products dates back to the 17th century but is likely much older. More recently, the electronic cigarette or "e-cigarette" and its accompanying flavored e-liquids emerged on to the global market. These new products contain no combustible tobacco but often contain large concentrations (reported from 0 to more than 50 mg/mL) of nicotine as well as numerous flavorings and/or flavor chemicals. At present, there are more than 400 e-cigarette brands available along with potentially >15,000 different/unique flavored products. However, surprisingly little is known about the flavors/flavor chemicals added to these products, which can account for >1% by weight of some e-liquids, and their resultant chemosensory experiences, and the US FDA has done relatively little, until recently, to regulate these products. This article will discuss e-cigarette flavors and flavor chemicals, their elicited responses, and their sensory effects in some detail.

Impact of Electronic Cigarette Vaping on Cerebral Ischemia: What We Know So Far

Electronic cigarettes (ECs) are battery-powered nicotine delivery devices that have rapidly gained popularity and attention globally. ECs work by heating a liquid to produce an aerosol that usually contains nicotine, flavoring compounds, and other chemicals, which are inhaled during vaping. EC aerosols are depicted to contain a lower number and overall quantity of harmful toxicants than conventional cigarettes (CCs). However, emerging research indicates that EC aerosols contain harmful ingredients including ultrafine particles, volatile organic compounds, and heavy metals. One common ingredient found in both CCs and ECs is nicotine, which has been shown to be both highly addictive and toxic. Particularly relevant to our current review, there is an enormous amount of literature that shows that smoking-derived nicotine exacerbates ischemic brain damage. Therefore, the question arises: will EC use impact the outcome of stroke? ECs are highly popular and relatively new in the market; thus, our understanding about the long-term effects of EC use on brain are lacking. The current review strives to extrapolate the existing understanding of the nicotine-induced effects of conventional smoking on the brain to the possible effects that ECs may have on the brain, which may ultimately have a potential for adverse stroke risk or severity.

Electronic cigarette vaping with aged coils causes acute lung injury in mice

Electronic cigarettes (e-cigarettes) have been used widely as an alternative to conventional cigarettes and have become particularly popular among young adults. A growing body of evidence has shown that e-cigarettes are associated with acute lung injury and adverse effects in multiple other organs. Previous studies showed that high emissions of aldehydes (formaldehyde and acetaldehyde) in aerosols were associated with increased usage of the same e-cigarette coils. However, the impact on lung function of using aged coils has not been reported. We investigated the relationship between coil age and acute lung injury in mice exposed to experimental vaping for 1 h (2 puffs/min, 100 ml/puff). The e-liquid contains propylene glycol and vegetable glycerin (50:50, vol) only. The concentrations of formaldehyde and acetaldehyde in the vaping aerosols increased with age of the nichrome coils starting at 1200 puffs. Mice exposed to e-cigarette aerosols produced from 1800, but not 0 or 900, puff-aged coils caused acute lung injury, increased lung wet/dry weight ratio, and induced lung inflammation (IL-6, TNF-α, IL-1β, MIP-2). Exposure to vaping aerosols from 1800 puff-aged coils decreased heart rate, respiratory rate, and oxygen saturation in mice compared to mice exposed to air or aerosols from new coils. In conclusion, we observed that the concentration of aldehydes (formaldehyde and acetaldehyde) increased with repeated and prolonged usage of e-cigarette coils. Exposure to high levels of aldehyde in vaping aerosol was associated with acute lung injury in mice. These findings show significant risk of lung injury associated with prolonged use of e-cigarette devices.

Association between Harmful and Addictive Perceptions of E-Cigarettes and E-Cigarette Use among Adolescents and Youth-A Systematic Review and Meta-Analysis

BACKGROUND

Recognising the association between the perceived risks of e-cigarettes and e-cigarette usage among youth is critical for planning effective prevention and intervention initiatives; thus, a systematic review and meta-analysis were performed.

METHODS

Fourteen databases were searched for eligible studies from the Inception of database until March 2022 to examine the effect estimates of the association between perceptions of harmfulness and addictiveness and overall e-cigarette usage among adolescents and youth.

RESULTS

The meta-analysis showed that in comparison to non-users, young people who were ever e-cigarette users were two times more likely to disagree that e-cigarettes are harmful (OR: 2.20, 95% CI: 1.41-3.43) and perceived e-cigarettes as less harmful than tobacco cigarettes (OR: 2.01, 95% CI 1.47-2.75). Youths who were ever e-cigarette users were also 2.3 and 1.8 times more likely to perceive e-cigarettes as less addictive (OR: 2.28, 95% CI: 1.81-2.88) or perceive e-cigarettes as more addictive (OR: 1.82, 95% CI: 1.22-2.73) than tobacco cigarettes, as compared with non-users. The subgroup analysis reported that adolescents were more likely to believe that e-cigarettes are less harmful than tobacco cigarettes, while youth users perceived otherwise.

CONCLUSION

the risk perceptions of e-cigarettes are associated with e-cigarette use among adolescents and youth and could be the focus of health promotion to prevent and curb the uptake of e-cigarettes among young people.

Embolic Stroke Following Ingestion of Liquid Nicotine Refill Solution

The use of e-cigarettes is gaining popularity despite knowing about cardiovascular health risks. Cases of intentional or accidental intoxication following ingestion of the refill solution are also a growing concern. Most of these cases were fatal and related to cardiac arrest and hypoxic brain injury. We report the case of a 54-year-old woman who developed bilateral acute ischemic stroke in the anterior and posterior cerebral circulation following intentional oral intake of e-liquid nicotine refill solution. The diagnostic work-up concluded an etiology of embolic stroke of undetermined source, most likely of cardiac origin. We assume that sympathetic overactivation lead to temporary cardiac arrhythmia and subsequent thrombi formation. Moreover, we discuss several additional pathogenic aspects of oral intake of e-liquid refill solution for the development of central nervous system pathology. This case expands the clinical spectrum of health hazards associated with the introduction of e-cigarettes and raises awareness of the need for preventive measures.

Effects of e-cigarette use on mental health among youths: quasi-experimental evidence from Canada

BACKGROUND AND AIMS

Existing research on mental health comorbidities of youth e-cigarette use is subject to confounding bias and reverse causality. This study aimed to measure the effects of e-cigarette use on youth mental health, using e-cigarette minimum legal age (MLA) law in Canada as a natural experiment.

DESIGN

We used difference-in-differences (DD), difference-in-differences-in-differences (DDD) and two-sample instrumental variables (TSIV) methods.

SETTING

Data were from nationally representative Canadian Community Health Surveys 2008-2019 and Canadian Student Tobacco Alcohol and Drugs Surveys 2008-2019.

PARTICIPANTS

The study sample comprised of respondents aged 15 to 18 (in DD analysis; n = 33 858) and aged 15 to 24 (in DDD analysis; n = 78 689).

MEASUREMENTS

Primary outcomes were self-reported mood disorders and anxiety disorders. Secondary outcomes were cannabis use, illicit drug use, cigarette use and strength of peer relationships at schools.

FINDINGS

After the e-cigarette MLA laws, risks of mood disorders declined by 1.9 percentage points (95% CI, 0.0-3.8; P = 0.05) in the DD analysis and by 2.6 percentage points (95% CI, 0.2-5.0; P = 0.03) in the DDD analysis. For anxiety disorders, while the DD estimate was negative but imprecisely estimated, the MLA law reduced risks of anxiety disorder by 3.6 percentage points (95% CI, 0.9-6.2; P = 0.01) in the DDD analysis. Youths in provinces with MLA laws were also less likely to report cannabis use and illicit drug use and more likely to feel being part of schools. TSIV analysis indicates that youth e-cigarette use increased the likelihood of mood and anxiety disorders by 44% and 37%, respectively.

CONCLUSION AND RELEVANCE

In Canada, the e-cigarette minimum legal age law appears to have reduced risks of mood and anxiety disorders, lowered substance use and improved peer relationships at schools. Combined with previous evidence of lower e-cigarette use following the minimum legal age law, our findings indicate that youth e-cigarette use increases risks of mood and anxiety disorders.

Single-nucleus chromatin accessibility and RNA sequencing reveal impaired brain development in prenatally e-cigarette exposed neonatal rats

Although emerging evidence reveals that vaping alters the function of the central nervous system, the effects of maternal vaping on offspring brain development remain elusive. Using a well-established in utero exposure model, we performed single-nucleus ATAC-seq (snATAC-seq) and RNA sequencing (snRNA-seq) on prenatally e-cigarette-exposed rat brains. We found that maternal vaping distorted neuronal lineage differentiation in the neonatal brain by promoting excitatory neurons and inhibiting lateral ganglionic eminence-derived inhibitory neuronal differentiation. Moreover, maternal vaping disrupted calcium homeostasis, induced microglia cell death, and elevated susceptibility to cerebral ischemic injury in the developing brain of offspring. Our results suggest that the aberrant calcium signaling, diminished microglial population, and impaired microglia-neuron interaction may all contribute to the underlying mechanisms by which prenatal e-cigarette exposure impairs neonatal rat brain development. Our findings raise the concern that maternal vaping may cause adverse long-term brain damage to the offspring.

Longitudinal Assessments of Neurocognitive Performance and Brain Structure Associated With Initiation of Tobacco Use in Children, 2016 to 2021

IMPORTANCE

The landscape of tobacco use is changing. However, information about the association between early-age tobacco use and cognitive performances is limited, especially for emerging tobacco products such as electronic cigarettes (e-cigarettes).

OBJECTIVE

To assess the association between early-age initiation of tobacco use and cognitive performances measured by the National Institutes of Health (NIH) Toolbox Cognitive Battery and to examine whether initiation is associated with differences in brain morphometry.

DESIGN, SETTING, AND PARTICIPANTS

This observational cohort study examined the longitudinal associations of initiation of tobacco use with neurocognition using multivariate linear mixed models. Children aged 9 to 10 years from 21 US sites were enrolled in wave 1 (October 1, 2016, to October 31, 2018 [n = 11 729]) and the 2-year follow-up (August 1, 2018, to January 31, 2021 [n = 10 081]) of the Adolescent Brain Cognitive Development (ABCD) Study.

EXPOSURES

Ever use (vs none) of any tobacco products at wave 1, including e-cigarettes, cigarettes, cigars, smokeless tobacco, hookah, pipes, and nicotine replacement.

MAIN OUTCOMES AND MEASURES

Neurocognition measured by the NIH Toolbox Cognition Battery and morphometric measures of brain structure and region of interest analysis for the cortex from structural magnetic resonance imaging.

RESULTS

Among 11 729 participants at wave 1 (mean [SE] age, 9.9 [0.6] years; 47.9% girls and 52.1% boys; 20.3% Hispanic; 14.9% non-Hispanic Black; and 52.1% non-Hispanic White), 116 children reported ever use of tobacco products. Controlling for confounders, tobacco ever users vs nonusers exhibited lower scores in the Picture Vocabulary Tests at wave 1 (b [SE] = -2.9 [0.6]; P < .001) and 2-year follow-up (b [SE] = -3.0 [0.7]; P < .001). The crystalized cognition composite score was lower among tobacco ever users than nonusers both at wave 1 (b [SE] = -2.4 [0.5]; P < .001) and 2-year follow-up (b [SE] = -2.7 [0.8]; P = .005). In structural magnetic resonance imaging, the whole-brain measures in cortical area and volume were significantly lower among tobacco users than nonusers, including cortical area (b [SE] = -5014.8 [1739.8] mm2; P = .004) at wave 1 and cortical volume at wave 1 (b [SE] = -174 621.0 [5857.7] mm3; P = .003) and follow-up (b [SE] = -21 790.8 [7043.9] mm3; P = .002). Further region of interest analysis revealed smaller cortical area and volume in multiple regions across frontal, parietal, and temporal lobes at both waves.

CONCLUSIONS AND RELEVANCE

In this cohort study, initiating tobacco use in late childhood was associated with inferior cognitive performance and reduced brain structure with sustained effects at 2-year follow-up. These findings suggest that youths vulnerable to e-cigarettes and tobacco products should be treated as a priority population in tobacco prevention.

Drugs, Guts, Brains, but Not Rock and Roll: The Need to Consider the Role of Gut Microbiota in Contemporary Mental Health and Wellness of Emerging Adults

Emerging adulthood (ages 18-25) is a critical period for neurobiological development and the maturation of the hypothalamic-pituitary-adrenal axis. Recent findings also suggest that a natural perturbation of the gut microbiota (GM), combined with other factors, may create a unique vulnerability during this period of life. The GM of emerging adults is thought to be simpler, less diverse, and more unstable than either younger or older people. We postulate that this plasticity in the GM suggests a role in the rising mental health issues seen in westernized societies today via the gut-brain-microbiota axis. Studies have paid particular attention to the diversity of the microbiota, the specific function and abundance of bacteria, and the production of metabolites. In this narrative review, we focus specifically on diet, physical activity/exercise, substance use, and sleep in the context of the emerging adult. We propose that this is a crucial period for establishing a stable and more resilient microbiome for optimal health into adulthood. Recommendations will be made about future research into possible behavioral adjustments that may be beneficial to endorse during this critical period to reduce the probability of a "dysbiotic" GM and the emergence and severity of mental health concerns.

Menthol Flavor in E-Cigarette Vapor Modulates Social Behavior Correlated With Central and Peripheral Changes of Immunometabolic Signalings

The use of electronic cigarette (e-cigarette) has been increasing dramatically worldwide. More than 8,000 flavors of e-cigarettes are currently marketed and menthol is one of the most popular flavor additives in the electronic nicotine delivery systems (ENDS). There is a controversy over the roles of e-cigarettes in social behavior, and little is known about the potential impacts of flavorings in the ENDS. In our study, we aimed to investigate the effects of menthol flavor in ENDS on the social behavior of long-term vapor-exposed mice with a daily intake limit, and the underlying immunometabolic changes in the central and peripheral systems. We found that the addition of menthol flavor in nicotine vapor enhanced the social activity compared with the nicotine alone. The dramatically reduced activation of cellular energy measured by adenosine 5′ monophosphate-activated protein kinase (AMPK) signaling in the hippocampus were observed after the chronic exposure of menthol-flavored ENDS. Multiple sera cytokines including C5, TIMP-1, and CXCL13 were decreased accordingly as per their peripheral immunometabolic responses to menthol flavor in the nicotine vapor. The serum level of C5 was positively correlated with the alteration activity of the AMPK-ERK signaling in the hippocampus. Our current findings provide evidence for the enhancement of menthol flavor in ENDS on social functioning, which is correlated with the central and peripheral immunometabolic disruptions; this raises the vigilance of the cautious addition of various flavorings in e-cigarettes and the urgency of further investigations on the complex interplay and health effects of flavoring additives with nicotine in e-cigarettes.

Use of electronic vaping products and mental health among adolescent high school students in the United States: The moderating effect of sex

Although studies have investigated the association between conventional tobacco smoking and mental health outcomes among adolescents in the United States, few studies have examined the association between electronic vaping products (EVPs) and mental health among adolescents. This study aimed to investigate the cross-sectional association between EVPs use, symptoms of depression, and suicidal behaviors among adolescents. Data were pooled from the 2017 and 2019 Youth Risk Behavior Survey. An analytic sample of 14,285 adolescents (50.3% female) was analyzed using binary logistic regression. The outcome variables investigated were symptoms of depression, suicidal ideation, suicide plan, and suicide attempts, and the main explanatory variable was EVPs use. Of the 14,285 adolescents, 22.2%, 19.2%, and 58.8% were current, former and never users of EVPs, respectively. Controlling for other factors, current users of EVPs were significantly more likely to report having symptoms of depression (AOR = 1.82, 95% CI = 1.58-2.09), having suicidal ideation (AOR = 1.55, 95% CI = 1.30-1.86), making a suicide plan (AOR = 1.62, 95% CI = 1.34-1.97), or attempting suicide (AOR = 1.75, 95% CI = 1.41-2.18) when compared to never users of EVPs. Gender moderated the association between EVPs use, symptoms of depression, suicidal ideation, and suicide plan. Racial minority identity, sexual minority identity, sexual violence victimization, victim of school and cyberbullying, alcohol use, and cigarette smoking were all significantly associated with depression and suicidal behaviors. Study findings support the association between EVPs use and adolescent mental health. Future studies that employ longitudinal designs may offer more insight into the mechanisms underlying this association.

Exposure to e-cigarette aerosol over two months induces accumulation of neurotoxic metals and alteration of essential metals in mouse brain

Despite a recent increase in e-cigarette use, the adverse human health effects of exposure to e-cigarette aerosol, especially on the central nervous system (CNS), remain unclear. Multiple neurotoxic metals have been identified in e-cigarette aerosol. However, it is unknown whether those metals accumulate in the CNS at biologically meaningful levels. To answer this question, two groups of mice were whole-body exposed twice a day, 5 days a week, for two months, to either a dose of e-cigarette aerosol equivalent to human secondhand exposure, or a 5-fold higher dose. After the last exposure, the olfactory bulb, anterior and posterior frontal cortex, striatum, ventral midbrain, cerebellum, brainstem, remaining brain tissue and spinal cord were collected for metal quantification by inductively coupled plasma mass spectrometry and compared to tissues from unexposed control mice. The two-month exposure caused significant accumulation of several neurotoxic metals in various brain areas - for some metals even at the low exposure dose. The most striking increases were measured in the striatum. For several metals, including Cr, Cu, Fe, Mn, and Pb, similar accumulations are known to be neurotoxic in mice. Decreases in some essential metals were observed across the CNS. Our findings suggest that chronic exposure to e-cigarette aerosol could lead to CNS neurotoxic metal deposition and endogenous metal dyshomeostasis, including potential neurotoxicity. We conclude that e-cigarette-mediated metal neurotoxicity may pose long-term neurotoxic and neurodegenerative risks for e-cigarette users and bystanders.

Fetal e-cigarette exposure programs a neonatal brain hypoxic-ischemic sensitive phenotype via altering DNA methylation patterns and autophagy signaling pathway

Maternal e-cigarette (e-cig) exposure is a pressing perinatal health concern. Emerging evidence reveals its potential adverse impacts on brain development in offspring, yet the underlying mechanisms are poorly understood. The present study tested the hypothesis that fetal e-cig exposure induces an aberrant DNA methylation profile in the developing brain, leading to alteration of autophagic flux signaling and programming of a sensitive phenotype to neonatal hypoxic-ischemic encephalopathy (HIE). Pregnant rats were exposed to chronic intermittent e-cig aerosol. Neonates were examined at the age of 9 days old. Maternal e-cig exposure decreased the body weight and brain weight but enhanced the brain-to-body weight ratio in the neonates. E-cig exposure induced a gender-dependent increase in hypoxic-ischemia-induced brain injury in male neonates associated with enhanced reactive oxygen species (ROS) activity. It differentially altered DNA methyltransferase expression and enhanced both global DNA methylation levels and specific CpG methylation at the autophagy-related gene 5 (ATG5) promoter. In addition, maternal e-cig exposure caused downregulations of ATG5, microtubule-associated protein 1 light chain 3β, and sirtuin 1 expression in neonatal brains. Of importance, knockdown of ATG5 in neonatal pups exaggerated neonatal HIE. In conclusion, the present study reveals that maternal e-cig exposure downregulates autophagy-related gene expression via DNA hypermethylation, leading to programming of a hypoxic-ischemic sensitive phenotype in the neonatal brain.

Substance use among adolescents and young adults with chronic kidney disease or kidney failure

Substance use, a significant public health issue, is well described in the adult chronic kidney disease (CKD) population. Knowledge about substance use in the adolescent and young adult (AYA) CKD population such as prevalence, impact on kidney function, medication adherence, and psychosocial well-being remain largely unknown. Awareness of and inquiring about substance use is paramount to providing evidence-based care and preparation to transition to adult-focused health services. The authors in this review identify commonly used substances (alcohol, tobacco, marijuana, etc.) and how they impact kidney function and care of the AYA with CKD or kidney failure. Recommendations for screening and intervention strategies are provided.

Electronic cigarette aerosol increases the risk of organ dysfunction by enhancing oxidative stress and inflammation

An electronic cigarette is a rechargeable device that produces an inhaled aerosol containing varying levels of nicotine, and inorganic and organic toxicants and carcinogenic compounds. The aerosol is generated by heating a solution of propylene glycol and glycerin with nicotine and flavoring ingredients at a high temperature. The e-cigarette was developed and marketed as a safer alternative to the regular cigarette which is known to be injurious to human health. However, published studies suggest that the aerosol of e-cigarette can also have adverse health effects. The main objective of this review is to briefly describe some consequences of e-cigarette smoking, and to present data showing that the resulting increased oxidative stress and inflammation are likely to be involved in effecting to lung damage. Other organs are also likely to be affected. The aerosol contains varying amounts of organic and inorganic toxicants as well as carcinogens, which might serve as the source of such deleterious events. In addition, the aerosol also contains nicotine, which is known to be addictive. E-cigarette smoking releases these toxicants into the air leading to inhalation by nonsmokers in residential or work place areas. Unlike regular tobacco smoke, the long-term consequences of direct and secondhand exposure to e-cigarette aerosol have not been extensively studied but based on available data, e-cigarette aerosol should be considered harmful to human health.

Novel Pharmacotherapies in Parkinson's Disease

Parkinson’s disease (PD), an age-related progressive neurodegenerative condition, is associated with loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc), which results in motor deficits characterized by the following: akinesia, rigidity, resting tremor, and postural instability, as well as nonmotor symptoms such as emotional changes, particularly depression, cognitive impairment, gastrointestinal, and autonomic dysfunction. The most common treatment for PD is focused on dopamine (DA) replacement (e.g., levodopa = L-Dopa), which unfortunately losses its efficacy over months or years and can induce severe dyskinesia. Hence, more efficacious interventions without such adverse effects are urgently needed. In this review, following a general description of PD, potential novel therapeutic interventions for this devastating disease are examined. Specifically, the focus is on nicotine and nicotinic cholinergic system, as well as butyrate, a short chain fatty acid (SCFA), and fatty acid receptors.

Toxicology of flavoring- and cannabis-containing e-liquids used in electronic delivery systems

Electronic cigarettes (e-cigarettes) were introduced in the United States in 2007 and by 2014 they were the most popular tobacco product amongst youth and had overtaken use of regular tobacco cigarettes. E-cigarettes are used to aerosolize a liquid (e-liquid) that the user inhales. Flavorings in e-liquids is a primary reason for youth to initiate use of e-cigarettes. Evidence is growing in the scientific literature that inhalation of some flavorings is not without risk of harm. In this review, 67 original articles (primarily cellular in vitro) on the toxicity of flavored e-liquids were identified in the PubMed and Scopus databases and evaluated critically. At least 65 individual flavoring ingredients in e-liquids or aerosols from e-cigarettes induced toxicity in the respiratory tract, cardiovascular and circulatory systems, skeletal system, and skin. Cinnamaldehyde was most frequently reported to be cytotoxic, followed by vanillin, menthol, ethyl maltol, ethyl vanillin, benzaldehyde and linalool. Additionally, modern e-cigarettes can be modified to aerosolize cannabis as dried plant material or a concentrated extract. The U.S. experienced an outbreak of lung injuries, termed e-cigarette, or vaping, product use-associated lung injury (EVALI) that began in 2019; among 2,022 hospitalized patients who had data on substance use (as of January 14, 2020), 82% reported using a delta-9-tetrahydrocannabinol (main psychoactive component in cannabis) containing e-cigarette, or vaping, product. Our literature search identified 33 articles related to EVALI. Vitamin E acetate, a diluent and thickening agent in cannabis-based products, was strongly linked to the EVALI outbreak in epidemiologic and laboratory studies; however, e-liquid chemistry is highly complex, and more than one mechanism of lung injury, ingredient, or thermal breakdown product may be responsible for toxicity. More research is needed, particularly with regard to e-cigarettes (generation, power settings, etc.), e-liquids (composition, bulk or vaped form), modeled systems (cell type, culture type, and dosimetry metrics), biological monitoring, secondhand exposures and contact with residues that contain nicotine and flavorings, and causative agents and mechanisms of EVALI toxicity.