Chronic exposure to e-cig aerosols during early development causes vascular dysfunction and offspring growth deficits

Influence of gestational window on offspring vascular health in rodents with in utero exposure to electronic cigarettes

Studies have shown cerebrovascular dysfunction in offspring with full-gestational electronic cigarette (Ecig) exposure, but little is known about how individual trimester exposure impacts offspring health. This study aimed to determine if there is a critical window during gestation that contributes to vascular and anxiety-like behavioural changes seen with full-term exposure. To test this, rats were time-mated, and the pregnant dams were randomly assigned to Ecig exposure during first trimester (gestational day, GD2-7), second trimester (GD8-14), third trimester (GD15-21) or full-term gestation (GD2-21). We also assessed the effect of maternal preconception exposure. Both male and female offspring from all maternal exposure conditions were compared to offspring from dams under ambient air (control) conditions. Ecig exposure consisted of 60-puffs/day (5 days/week) using either 5 or 30 watts for each respective exposure group. We found that maternal exposure to Ecig in the second and third trimesters resulted in a decrease (23-38%) in vascular reactivity of the middle cerebral artery (MCA) reactivity in 3- and 6-month-old offspring compared to Air offspring. Further, the severity of impairment was comparable to the full-term exposure (31-46%). Offspring also displayed changes in body composition, body mass, anxiety-like behaviour and locomotor activity, indicating that Ecigs influence neurodevelopment and metabolism. Maternal preconception exposure showed no impact on offspring body mass, anxiety-like behaviour, or vascular function. Thus, the critical exposure window where Ecig affects vascular development in offspring occurs during mid- to late-gestation in pregnancy, and both 5 W and 30 W exposure produce significant vascular dysfunction compared to Air. KEY POINTS: Exposure to electronic cigarettes (Ecigs) is known to increase risk factors for cardiovascular disease in both animals and humans. Maternal Ecig use during pregnancy in rodents is found to impair the vascular health of adolescent and adult offspring, but the critical gestation window for Ecig-induced vascular impairment is not known. This study demonstrates Ecig exposure during mid- and late-gestation (i.e. second or third trimester) results in impaired endothelial cell-mediated dilatation (i.e. middle cerebral artery reactivity) and alters anxiety-like behaviour in offspring. Maternal exposure prior to conception did not impact offspring's vascular or anxiety-like behavioural outcomes. Rodent models have been a reliable and useful predictor of inhalation-induced harm to humans. These data indicate maternal use of Ecigs during pregnancy should not be considered safe, and begin to inform clinicians and women about potential long-term harm to their offspring.

Guidelines for assessing maternal cardiovascular physiology during pregnancy and postpartum

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Long-Term Neurologic Consequences following Fetal Growth Restriction: The Impact on Brain Reserve

BACKGROUND

Fetal growth restriction (FGR) corresponds to the fetus's inability to achieve an adequate weight gain based on genetic potential and gestational age. It is an important cause of morbidity and mortality.

SUMMARY

In this review, we address the challenges of diagnosis and classification of FGR. We review how chronic fetal hypoxia impacts brain development. We describe recent advances on placental and fetal brain imaging using magnetic resonance imaging and how they offer new noninvasive means to study growth restriction in humans. We go on to review the impact of FGR on brain integrity in the neonatal period, later childhood, and adulthood and review available therapies.

KEY MESSAGES

FGR consequences are not limited to the perinatal period. We hypothesize that impaired brain reserve, as defined by structure and size, may predict some concerning epidemiological data of impaired cognitive outcomes and dementia with aging in this group of patients.

Vaping-Dependent Pulmonary Inflammation Is Ca2+ Mediated and Potentially Sex Specific

Here we use the SCIREQ InExpose system to simulate a biologically relevant vaping model in mice to investigate the role of calcium signaling in vape-dependent pulmonary disease as well as to investigate if there is a gender-based difference of disease. Male and female mice were vaped with JUUL Menthol (3% nicotine) using the SCIREQ InExpose system for 2 weeks. Additionally, 2-APB, a known calcium signaling inhibitor, was administered as a prophylactic for lung disease and damage caused by vaping. After 2 weeks, mice were exposed to lipopolysaccharide (LPS) to mimic a bacterial infection. Post-infection (24 h), mice were sacrificed, and bronchoalveolar lavage fluid (BALF) and lungs were taken. Vaping primed the lungs for worsened disease burden after microbial challenge (LPS) for both males and females, though females presented increased neutrophilia and inflammatory cytokines post-vape compared to males, which was assessed by flow cytometry, and cytokine and histopathological analysis. This increased inflammatory burden was controlled by calcium signaling inhibition, suggesting that calcium dysregulation may play a role in lung injury caused by vaping in a gender-dependent manner.

Electronic cigarette use during pregnancy and the risk of adverse birth outcomes: A cross-sectional surveillance study of the US Pregnancy Risk Assessment Monitoring System (PRAMS) population

BACKGROUND

Research on health effects and potential harms of electronic cigarette (EC) use during pregnancy is limited. We sought to determine the risks of pregnancy EC use on pregnancy-related adverse birth outcomes and assess whether quitting ECs reduces the risks.

METHODS

Women with singleton live births who participated in the US Pregnancy Risk Assessment Monitoring System (PRAMS) survey study 2016-2020 were classified into four mutually exclusive groups, by their use of ECs and combustible cigarettes (CCs) during pregnancy: non-use, EC only use, CC only use, and dual use. We determined the risk of preterm birth, low birth weight, and small-for-gestational-age (SGA) by comparing cigarette users to non-users with a modified Poisson regression model adjusting for covariates. In a subset of women who all used ECs prior to pregnancy, we determined whether quitting EC use reduces the risk of preterm birth, low birth weight, and SGA by comparing to those who continued its use. All analyses were weighted to account for the PRAMS survey design and non-response rate.

RESULTS

Of the 190,707 women (weighted N = 10,202,413) included, 92.1% reported cigarette non-use, 0.5% EC only use, 6.7% CC only use, and 0.7% dual use during pregnancy. Compared with non-use, EC only use was associated with a significantly increased risk of preterm birth (adjusted risk ratio [aRR]: 1.29, 95% confidence interval [CI]: 1.00, 1.65) and low birth weight (aRR: 1.38, 95%CI: 1.09, 1.75), but not SGA (aRR: 1.04, 95%CI: 0.76, 1.44). Among 7,877 (weighted N = 422,533) women EC users, quitting use was associated with a significantly reduced risk of low birth weight (aRR: 0.76, 95%CI: 0.62, 0.94) and SGA (aRR: 0.77, 95%CI: 0.62, 0.94) compared to those who continued to use ECs during pregnancy.

CONCLUSIONS

Pregnancy EC use, by itself or dual use with CC, is associated with preterm birth and low birth weight. Quitting use reduces that risk. ECs should not be considered as a safe alternative nor a viable gestational smoking cessation strategy.

Cigarette Smoking Abstinence Among Pregnant Individuals Using E-Cigarettes or Nicotine Replacement Therapy

Importance

Smoking cigarettes during pregnancy can impair maternal and child health, and pregnant individuals have increasingly used electronic cigarettes (e-cigarettes) for various reasons, including quitting smoking.

Objective

To assess smoking abstinence rates among pregnant individuals who used e-cigarettes compared with those who used nicotine replacement therapy (NRT).

Design, Setting, and Participants

This cohort study is a secondary data analysis of phase 8 of the US Pregnancy Risk Assessment Monitoring System, conducted between 2016 and 2020. Eligible participants included pregnant individuals who smoked combustible cigarettes within the 3 months before pregnancy and either used e-cigarettes or NRT during pregnancy. Data analysis was conducted from March 2022 to April 2023.

Exposures

Combustible cigarette use within 3 months before pregnancy and use of either e-cigarettes or NRT during pregnancy.

Main Outcomes and Measures

The primary outcome was the individual's self-reported smoking abstinence status during the last 3 months of pregnancy. Weighted percentages were reported and weighted multivariable logistic regression models were used to examine the association of e-cigarette use vs NRT with smoking abstinence. A propensity score was used to control for confounding by sociodemographics, pregnancy characteristics, prepregnancy smoking intensity, depression, behavioral support, and hookah use.

Results

The cohort included 1329 pregnant individuals (759 ≥25 years [60.2%]; 766 non-Hispanic White individuals [79.8%]) of whom 781 had an education level of high school or lower (61.4%), and 952 had an annual household income of $48 000 or less (81.5%). Of the 1329 individuals, 890 (unweighted percentage, 67.0%) were existing e-cigarette users, 67 (unweighted percentage, 5.0%) were new e-cigarette users, and 372 (unweighted percentage, 28.0%) were NRT users. Compared with individuals who used NRT during pregnancy, individuals who used e-cigarettes had a higher rate of smoking abstinence in late pregnancy (456 individuals [50.8%] vs 67 individuals [19.4%]; propensity score adjusted odds ratio [OR], 2.47; 95% CI, 1.17-5.20; P = .02). In the secondary analysis stratified by the timing of e-cigarette use initiation, existing users of e-cigarettes who initiated before pregnancy had a higher smoking abstinence rate than NRT users (446 users [53.1%] vs 67 users [19.4%]; adjusted OR, 2.61; 95% CI, 1.23-5.51; P = .01). However, new e-cigarette users who initiated use during pregnancy had a similar smoking abstinence rate in late pregnancy when compared with NRT users (10 users [20.6%] vs 67 users [19.4%]; adjusted OR, 1.13; 95% CI, 0.22-5.87; P = .88).

Conclusions and Relevance

These findings suggest that individuals who used e-cigarettes during pregnancy had a higher smoking abstinence rate in late pregnancy than individuals who used NRT, especially for those who initiated e-cigarette use before pregnancy, indicating that replacement of cigarettes with e-cigarettes during pregnancy may be a viable strategy for harm reduction.

Cardiopulmonary Impact of Electronic Cigarettes and Vaping Products: A Scientific Statement From the American Heart Association

Vaping and electronic cigarette (e-cigarette) use have grown exponentially in the past decade, particularly among youth and young adults. Cigarette smoking is a risk factor for both cardiovascular and pulmonary disease. Because of their more limited ingredients and the absence of combustion, e-cigarettes and vaping products are often touted as safer alternative and potential tobacco-cessation products. The outbreak of e-cigarette or vaping product use-associated lung injury in the United States in 2019, which led to >2800 hospitalizations, highlighted the risks of e-cigarettes and vaping products. Currently, all e-cigarettes are regulated as tobacco products and thus do not undergo the premarket animal and human safety studies required of a drug product or medical device. Because youth prevalence of e-cigarette and vaping product use was as high as 27.5% in high school students in 2019 in the United States, it is critical to assess the short-term and long-term health effects of these products, as well as the development of interventional and public health efforts to reduce youth use. The objectives of this scientific statement are (1) to describe and discuss e-cigarettes and vaping products use patterns among youth and adults; (2) to identify harmful and potentially harmful constituents in vaping aerosols; (3) to critically assess the molecular, animal, and clinical evidence on the acute and chronic cardiovascular and pulmonary risks of e-cigarette and vaping products use; (4) to describe the current evidence of e-cigarettes and vaping products as potential tobacco-cessation products; and (5) to summarize current public health and regulatory efforts of e-cigarettes and vaping products. It is timely, therefore, to review the short-term and especially the long-term implications of e-cigarettes and vaping products on cardiopulmonary health. Early molecular and clinical evidence suggests various acute physiological effects from electronic nicotine delivery systems, particularly those containing nicotine. Additional clinical and animal-exposure model research is critically needed as the use of these products continues to grow.

E-cigarette awareness and use, among adult residents in Shanghai, China

INTRODUCTION

The widespread popularity of e-cigarettes is considered an important public health concern. However, only some studies have investigated the prevalence of e-cigarette use in Shanghai, China. Research on the perceived harmfulness of e-cigarettes and public support for e-cigarette regulations in China is limited. This study aimed to estimate e-cigarette awareness, prevalence, and associated factors among adults in Shanghai, China.

METHODS

This study used data from a representative survey conducted in Shanghai, China, in 2019. The survey was conducted at 64 surveillance points in Shanghai, China, using a multistage, stratified, cluster-randomized sampling design, recruiting community-based Chinese adults aged ≥15 years. Based on the principles outlined in the Global Adult Tobacco Survey (GATS) China Project, data were collected by conducting face-to-face interviews in households. Of the 3200 selected households, 3060 people completed the individual survey. The overall response rate was 97.4%.

RESULTS

In all, 72.3% of the respondents had heard of e-cigarettes. The respondents who had used e-cigarettes at some point in their life, used them in the last 12 months, and used them currently were 5.8%, 2.6%, and 1.3%, respectively. Among adult residents who had heard of e-cigarettes, 38.2% thought they were less harmful than traditional cigarettes. The respondents who perceived e-cigarettes as more harmful than traditional cigarettes were less likely to have ever used e-cigarettes (AOR=0.2; 95% CI: 0.1-0.5, p=0.0015) and more likely to support incorporating e-cigarettes into the regulation of smoking control (AOR=3.9; 95% CI: 1.8-8.6, p=0.0008).

CONCLUSIONS

Our findings reveal that the awareness about e-cigarettes was high, and the prevalence of e-cigarette use was similar to the findings from previous studies in China. The harmful perception of e-cigarettes warrants further attention from public health practitioners.

Impact of e-cigarette vaping aerosol exposure in pregnancy on mTOR signaling in rat fetal hippocampus

Electronic cigarette (e-cig) use during pregnancy has become a major health concern in recent years and many view them as less harmful and may help quit or reduce combustible cigarettes. Implementing a state-of-the-art engineered vaping system, comprising an atomizer similar to those sold in vape shops, we aimed to utilize a translational e-cig inhalation delivery method to provide crucial information on the impact of prenatal e-cig aerosols on the developing brain hippocampal mTOR system in a rat model system. Gestational e-cig vaping significantly increased P-mTOR levels (p < 0.05) in the rat fetal hippocampi in the nicotine group (comprising of VG/PG + nicotine) compared to the control and the juice (comprising of VG/PG) groups. Total mTOR expression was not different among groups. Immunofluorescence imaging demonstrated P-mTOR was detected exclusively in the granule cells of the dentate gyrus of the fetal hippocampus. E-cig did not alter DEPTOR, but RAPTOR and RICTOR were higher (p < 0.05) in the Nicotine group. Gestational e-cig vaping with nicotine increased (p < 0.05) the activity and expression of 4EBP1, p70S6K, but decreased (p < 0.05) P-PKCα in the fetal hippocampi. In summary, dysregulation of mTORC1 and the related mTORC2, their activity, and downstream proteins together may play a critical role in e-cig-vaping-induced neurobiological phenotypes during development.

An Overview of E-Cigarette Impact on Reproductive Health

Electronic cigarettes (e-cigarettes) are often considered a "safe substitute" for conventional cigarette cessation. The composition of the fluid is not always clearly defined and shows a large variation within brands and manufacturers. More than 80 compounds were detected in liquids and aerosols. E-cigarettes contain nicotine, and the addition of flavorings increases the toxicity of e-cigarette vapour in a significant manner. The heat generated by the e-cigarette leads to the oxidation and decomposition of its components, eventually forming harmful constituents in the inhaled vapour. The effects of these toxicants on male and female reproduction are well established in conventional cigarette smokers. Although toxins were measured at much lower levels in e-cigarette aerosols compared to smoke from a conventional cigarette, there are concerns about their potential impact on male and female reproduction. The information available was mainly obtained from studies conducted in animal models, and investigations in humans are scarce. However, the effects observed in animal models suggest that caution should be taken when vaping and that more research needs to be conducted to identify its potential adverse effects on fertility. The prevalence of e-cigarette usage is alarming, and warnings should be made about the impact of vaping on reproductive health. This document reviews the data regarding the impact of e-cigarette use on male and female reproduction.

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.

Adverse Maternal and Infant Outcomes of Women Who Differ in Smoking Status: E-Cigarette and Tobacco Cigarette Users

The electronic cigarette (e-cigarette) became commercially available around 2004, yet the characteristics of pregnant women who use these devices and their effects on maternal and infant health remain largely unknown. This study aimed to investigate maternal characteristics and pregnancy outcomes according to maternal smoking status. We conducted a cross-sectional study of Dutch women with reported pregnancies between February 2019 and May 2022, using an online questionnaire to collect data on smoking status and demographic, lifestyle, pregnancy, and infant characteristics. Smoking status is compared among non-smokers, tobacco cigarette users, e-cigarette users, and dual users (tobacco and e-cigarette). We report descriptive statistics and calculate differences in smoking status between women with the chi-square or Fisher (Freeman-Halton) test. Of the 1937 included women, 88.1% were non-smokers, 10.8% were tobacco cigarette users, 0.5% were e-cigarette users, and 0.6% were dual users. Compared with tobacco users, e-cigarette users more often reported higher education, having a partner, primiparity, and miscarriages. Notably, women who used e-cigarettes more often had small infants for gestational age. Despite including few women in the e-cigarette subgroup, these exploratory results indicate the need for more research to examine the impact of e-cigarettes on pregnancy outcomes.

Maternal electronic cigarette use during pregnancy affects long-term arterial function in offspring

Vaping, or electronic cigarette (ecig) use, is prevalent among pregnant women, although little is known about the effects of perinatal ecig use on cardiovascular health of the progeny (even when using nicotine-free e-liquid). Maternal toxicant inhalation may adversely affect vital conduit vessel development. We tested the hypothesis that perinatal exposure to maternal vaping would lead to a dose-dependent dysfunction that would persist into later life of offspring. Pregnant Sprague-Dawley rats were exposed to either nicotine-free (ecig0) or nicotine-containing ecig aerosol (18 mg/mL, ecig18) starting on gestational day 2 and continued until pups were weaned (postnatal day 21). Pups were never directly exposed. Conduit artery function (stiffness and reactivity) and structure were assessed in 3- and 7-mo-old offspring. At 3 mo, pulse wave velocity (PWV) in the ecig0 and ecig18 offspring was significantly higher than controls in both the 20 puffs/day (6.6 ± 2.1 and 4.8 ± 1.3 vs. 3.2 ± 0.7 m/s, respectively, P < 0.05, means ± SD) and in 60 puffs/day exposure cohort (7.5 ± 2.8 and 7.5 ± 2.5 vs. 3.2 ± 0.5 m/s, respectively, P < 0.01). Wire myography revealed (range of 23%-31%) impaired aortic relaxation in all ecig exposure groups (with or without nicotine). Incubation of vessels with TEMPOL or Febuxostat reversed the aortic dysfunction, implicating the involvement of reactive oxygen species. Nearly identical changes and pattern was seen in vascular outcomes of 7-mo-old offspring. The take-home message from this preclinical study is that maternal vaping during pregnancy, with or without nicotine, leads to maladaptations in vascular (aortic) development that persist into adult life of offspring.NEW & NOTEWORTHY We observe a significant alteration in arterial structure and function in adolescent and adult offspring due to developmental exposure to toxicants resulting from perinatal maternal vaping. Taken together with previous work that described lasting dysfunction in cerebral microvasculature in offspring, these data underscore the adverse consequences of maternal exposure to electronic cigarette aerosol in conduit and resistance vessels alike, irrespective of nicotine content.

Ex vivo toxicity of E-cigarette constituents on human placental tissues

Globally, ∼50 % of women smoke during pregnancy and the prevalence of vaping is increasing among women of reproductive age. However, the health effects of vaping during pregnancy are largely unknown. This study examined the effects of e-cig constituents alone and in combination (propylene glycol [PG], vegetable glycerin [VG], and nicotine) on human placental tissue viability (MTT assay) and immunoassayed levels of placenta-derived biomarkers, i.e., 8-isoprostane (8-IsoP), heme oxygenase-1 (HO-1), interleukin-6 (IL-6), β-estradiol (E₂), progesterone (P₄), allopregnanolone (AP), and brain-derived neurotrophic factor (BDNF). Placental explant cultures were exposed ex vivo for 24 h to media-containing either nicotine (0-5000 nM), PG/VG (0-8 % v/v at 50/50 ratio), or a combination of both. No effects on tissue viability were observed at PG/VG concentrations < 8 % (v/v), while viability significantly reduced at PG/VG concentrations ≥ 10 % (v/v); biomarker studies employed only non-cytotoxic doses. Exposure to PG/VG decreased levels of 8-IsoP, IL-6, and E_2, and treatment with 2 % or 8 % PG/VG significantly reduced HO-1 levels, compared to non-treated controls. Exposure to nicotine alone at 2,500 nM and 5,000 nM reduced MTT activity by 20 % (P = 0.04) and 70 % (P < 0.001), respectively, and significantly increased (P < 0.001) levels of HO-1 and BDNF, compared to controls. Treatment with nicotine alone and in combination with PG/VG reduced IL-6 and E₂ levels. Interestingly, nicotine-induced toxicity was attenuated by PG/VG addition to nicotine-treated groups. These studies demonstrate that e-cig constituents negatively impact the human placenta and alters production of critical placental biomarkers, suggesting that vaping is an unsafe alternative for pregnant women or their unborn fetus.

Impact of E-cig aerosol vaping on fetal and neonatal respiratory development and function

Electronic cigarette (e-cig) use has increased over the past decade, and exposure to e-cig aerosols during pregnancy raises concern for maternal and fetal health. The developing fetal lung is known to be sensitive to prenatal tobacco product exposure. Utilizing a 3-pronged approach, we examined the effects of prenatal e-cig aerosols with, and without nicotine on respiratory development in a murine model. RNAseq analysis of fetal lungs revealed extensive dysregulation in gene expression. Morphologic assessment of distal airspaces in neonatal lungs display an emphysematic phenotype. Respiratory mechanics of neonates display signs of increased respiratory workload, with increased resistance and decreased compliance. These data are novel and provide evidence that prenatal e-cig exposure may result in altered lung function or development of disease.

Understanding the relationship between social determinants of health and maternal mortality: Scientific Impact Paper No. 67

Within this document we use the terms pregnant woman and women's health. However, it is important to acknowledge that it is not only people who identify as women for whom it is necessary to access care. Obstetric and gynaecology services and delivery of care must therefore be appropriate, inclusive and sensitive to the needs of those individuals whose gender identity does not align with the sex they were assigned at birth.

Maternal electronic cigarette exposure in relation to offspring development: a comprehensive review

Electronic cigarettes (e-cigarettes) have become increasingly popular in young generations in the United States. Because the adverse pregnancy outcomes associated with combustible cigarette smoking are well-recognized, many pregnant women switch to e-cigarettes believing that this alternative is low in toxic chemicals. However, most e-cigarettes contain nicotine, which can easily pass through the placenta and accumulate to a high concentration in fetal blood circulation. Studies have also detected toxic metals (eg, lead, cadmium, and nickel) in e-cigarettes, and carbonyl compounds and flavorings, which are suggested to be irritative and even carcinogenic. There are questions that need to be answered about the risks of e-cigarette exposure during pregnancy. Unfortunately, research evaluating the association between maternal e-cigarette exposure and offspring health is scarce, especially with regard to human studies. Some evidence from laboratory and animal studies, although inconsistent, showed that maternal exposure to e-cigarette vapor may lead to restricted growth of offspring. E-cigarette exposure may also have an impact on the metabolic health of offspring, manifested as distorted glucose homeostasis and energy metabolism. In addition, in utero exposure may lead to defects in respiratory, vascular, and neurologic system development. For humans, investigations mostly focused on immediate birth outcomes such as small-for-gestational-age neonates, low birthweight, and preterm birth; however, the results were inconclusive. Research also suggests that maternal e-cigarette exposure may result in compromised neurodevelopment in newborns. In summary, current evidence is insufficient to rigorously evaluate the health impacts of maternal e-cigarette use on offspring development. Future investigations are warranted.

Developmental Effects of Electronic Cigarette Use

Electronic cigarettes have gained widespread acceptance among adolescents and young adults. As a result of this popularity, there are concerns regarding the potential harm of primary, secondhand and thirdhand electronic cigarette exposures on fetal and postnatal development. In vitro studies have shown that constituents in electronic cigarette liquids, including nicotine, flavorings, and carrier agents can alter cellular processes and growth. Additionally, aerosolized electronic cigarette emissions have been shown to disrupt organ development and immune responses in preclinical studies. In clinical studies, an association between electronic cigarette use and frequent respiratory symptoms, greater asthma severity and impaired mucociliary clearance has been demonstrated with adolescent and young adult users of electronic cigarettes having twice the frequency of cough, mucus production, or bronchitis compared to nonusers. Along with the popularity of electronic cigarette use, secondhand electronic cigarette exposure has increased substantially; with almost one-fourth of middle and high school children reporting exposure to secondhand vapors. The health consequences of secondhand electronic cigarette exposure on children and other vulnerable populations are poorly understood but detectable levels of cotinine have been measured in nonusers. Pregnant women and their offspring are another vulnerable group at increased risk for health consequences from electronic cigarette exposure. Nicotine crosses the placenta and can disrupt brain and lung development in preclinical studies. This article will focus on the physiological and health effects associated with primary or secondhand exposure to electronic cigarettes. It is expected that with ongoing availability of electronic cigarettes as well as the accumulation of additional follow-up time for long-term outcomes, the risks associated with exposure will become better clarified. © 2022 American Physiological Society. Compr Physiol 12:3337-3346, 2022.

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.

Effects of Prenatal Electronic Cigarette Exposure On Foetal Development: a Review of the Literature

Since their market launch in 2007, e-cigarettes gained popularity and were considered a relatively safe alternative to traditional cigarettes. Pregnant women and women of childbearing age in particular are increasingly turning to e-cigarettes. Little is known about the effects of prenatal exposure on the affected foetus. This paper aims to provide an overview of the current research on the effects of prenatal e-cigarette exposure on the foetus. Since studies in humans are lacking to date, this review refers only to animal and in vitro analyses. The PubMed and Web of Science databases were used for an extensive literature search. The search yielded N = 17 significant research papers. Possible sequelae resulting from prenatal exposure to traditional cigarettes were also seen in prenatal exposure to e-cigarettes. Prenatal e-cigarette exposure was found to be associated with increased DNA methylation overall, resulting in lower gene expression. This could adversely impact the development of affected children, especially in case of those genes relevant to their development. In mice, for example, this greatly reduced the cell vitality of neural and stem cells and increased cell death. Further, prenatal exposure to e-cigarettes resulted in numerous developmental disorders, such as malformations of facial morphology and lower birth weight. Moreover, in animal models the animals suffered from a deterioration of their short-term memory. Activity and cognitive flexibility increased, while anxiety behaviour decreased. It is clear that more research and especially studies of humans are needed on this issue. In addition, there is a need for more intense education of prenatal care professionals as well as women of childbearing age and during pregnancy.

Calcium-Dependent Pulmonary Inflammation and Pharmacological Interventions and Mediators

Pulmonary diseases present a significant burden worldwide and lead to severe morbidity and mortality. Lung inflammation caused by interactions with either viruses, bacteria or fungi is a prominent characteristic of many pulmonary diseases. Tobacco smoke and E-cig use ("vaping") are considered major risk factors in the development of pulmonary disease as well as worsening disease prognosis. However, at present, relatively little is known about the mechanistic actions by which smoking and vaping may worsen the disease. One theory suggests that long-term vaping leads to Ca2+ signaling dysregulation. Ca2+ is an important secondary messenger in signal transduction. Cellular Ca2+ concentrations are mediated by a complex series of pumps, channels, transporters and exchangers that are responsible for triggering various intracellular processes such as cell death, proliferation and secretion. In this review, we provide a detailed understating of the complex series of components that mediate Ca2+ signaling and how their dysfunction may result in pulmonary disease. Furthermore, we summarize the recent literature investigating the negative effects of smoking and vaping on pulmonary disease, cell toxicity and Ca2+ signaling. Finally, we summarize Ca2+-mediated pharmacological interventions that could potentially lead to novel treatments for pulmonary diseases.

The chemistry and toxicology of vaping

Vaping is the process of inhaling and exhaling an aerosol produced by an e-cigarette, vape pen, or personal aerosolizer. When the device contains nicotine, the Food and Drug Administration (FDA) lists the product as an electronic nicotine delivery system or ENDS device. Similar electronic devices can be used to vape cannabis extracts. Over the past decade, the vaping market has increased exponentially, raising health concerns over the number of people exposed and a nationwide outbreak of cases of severe, sometimes fatal, lung dysfunction that arose suddenly in otherwise healthy individuals. In this review, we discuss the various vaping technologies, which are remarkably diverse, and summarize the use prevalence in the U.S. over time by youths and adults. We examine the complex chemistry of vape carrier solvents, flavoring chemicals, and transformation products. We review the health effects from epidemiological and laboratory studies and, finally, discuss the proposed mechanisms underlying some of these health effects. We conclude that since much of the research in this area is recent and vaping technologies are dynamic, our understanding of the health effects is insufficient. With the rapid growth of ENDS use, consumers and regulatory bodies need a better understanding of constituent-dependent toxicity to guide product use and regulatory decisions.

Prevalence and Distribution of Electronic Cigarette Use Before and During Pregnancy Among Women in 38 States of the United States

INTRODUCTION

To examine the prevalence and the changing pattern of e-cigarette use from preconception to pregnancy.

AIMS AND METHODS

This is a cross-sectional study using data from the multi-site Pregnancy Risk Assessment Monitoring System in the United States, 2016-2017. All participating mothers with information on e-cigarette use before and during pregnancy were included. Self-reported information about e-cigarette use were assessed using questionnaires. Weighted prevalences of e-cigarette use before and during pregnancy were calculated. Multivariable logistic regressions were used to examine the association between various demographic characteristics and e-cigarette use before or during pregnancy.

RESULTS

This study included 69 508 pregnant women from 38 states in the United States. The weighted prevalence of e-cigarette use before pregnancy and during the last 3 months of pregnancy was 3.6% (95% confidence interval [CI] 3.4%-3.9%) and 1.1% (0.9%-1.2%), respectively. The prevalence varied across states, ranging from 1.3% to 8.3% for e-cigarette use before pregnancy and from 0.1% to 3.4% for e-cigarette use during the last 3 months of pregnancy. Among women who used e-cigarettes before pregnancy, 24.4% (21.7%-27.1%) continued to use e-cigarettes during pregnancy. Among women who used e-cigarettes during pregnancy, 62.3% (56.5%-68.0%) were dual users. In multivariable analyses, cigarette smoking was most strongly associated with e-cigarette use. The adjusted odds ratio comparing smokers with nonsmokers before pregnancy was 11.10 (95% CI 9.34-13.20) for e-cigarette use before pregnancy and 6.72 (95% CI 4.38-10.31) for e-cigarette use during pregnancy.

CONCLUSIONS

Using data from 38 states in the United States, we showed geographical variations in the prevalence of e-cigarette use before and during pregnancy. Among women who used e-cigarettes before pregnancy, a quarter of them continued to use e-cigarettes during pregnancy. Conventional cigarette use is a strong risk factor for e-cigarette use before and during pregnancy. The prevalence of e-cigarette use needs to be monitored continuously.

IMPLICATIONS

This study provides important information to understand the status and changing patterns of e-cigarette use in pregnant women in the United States. Among pregnant women in 38 states in the United States, 3.6% of them used e-cigarettes during the 3 months before pregnancy and 1.1% used them during the last 3 months of pregnancy. The prevalence varied across states. A quarter of women who used e-cigarettes before pregnancy continued to use e-cigarettes during pregnancy. Cigarette smoking is the strongest predictor of e-cigarette use. Future research about health effects of e-cigarette use during pregnancy is in urgent need.

Impact of gestational electronic cigarette vaping on amino acid signature profile in the pregnant mother and the fetus

Background

Electronic cigarettes (e-cigs) are a form of tobacco product that has become increasingly popular over the past decade. Despite the known health consequences of tobacco product exposure during pregnancy, a substantial number of daily smokers will continue to smoke during pregnancy. Our current knowledge on the effects of e-cig aerosol exposure during pregnancy is limited to a small number of animal studies, which have identified several e-cig aerosol-induced disruptions to the physiology of normal development.

Methods

To further assess the impact of prenatal e-cig aerosol exposure on maternal and fetal health, we examined the amino acid signature profiles in maternal and fetal plasma, as well as in the fetal lungs, a sensitive target organ for prenatal tobacco product exposure. Pregnant Sprague Dawley rats were randomly assigned to one of three groups and were exposed to either e-cig aerosols containing nicotine, e-cig aerosols without nicotine, or room air. Dams were exposed utilizing a state-of-the-art custom engineered e-cig vaping system that is compatible with commercially available e-cig atomizers and enables a translational inhalation delivery method comparable to human vaping.

Results

We determined that gestational exposure to e-cig aerosols results in significant alterations to the amino acid profile in the maternal and fetal compartments, including the fetal lungs. The data shows a targeted disruption to the nitric oxide pathway, branched-chain amino acid metabolism, fetal protein synthesis, and urea cycle.

Conclusion

The data presented herein provides additional support that gestational e-cig aerosol exposure can impact crucial biological processes and exemplifies the need for extensive research on exposure to e-cig aerosols.

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First report of e-cig induced alterations to maternal/fetal amino acid profile.

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Translational vaping paradigm utilizing custom engineered vaping system.

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Analysis of amino acids show gestational e-cig exposure has significant effects.

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Fetal lungs may be a sensitive target to gestational e-cig aerosol exposure.

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Marker of dysregulation in branched-chain amino acid metabolism and urea cycle.

Adverse Birth Outcomes Associated With Prepregnancy and Prenatal Electronic Cigarette Use

OBJECTIVE

To evaluate the risk of adverse birth outcomes among adults who use electronic cigarettes (e-cigarettes) before and during pregnancy.

METHODS

Data from the 2016-2018 PRAMS (Pregnancy Risk Assessment Monitoring System) were used to assess the association between e-cigarette use during the 3 months before and last 3 months of pregnancy among 79,176 individuals with a recent live birth and the following birth outcomes: preterm birth, small for gestational age, and low birth weight (LBW). Adjusted prevalence ratios were generated using average marginal predictions from multivariable logistic regression models. Models were stratified by prenatal combustible cigarette smoking and frequency of e-cigarette use (daily or less than daily use).

RESULTS

In the 3 months before pregnancy, 2.7% (95% CI 2.6-2.9%) of respondents used e-cigarettes; 1.1% (95% CI 1.0-1.2%) used e-cigarettes during the last 3 months of pregnancy. Electronic cigarette use before pregnancy was not associated with adverse birth outcomes. Electronic cigarette use during pregnancy was associated with increased prevalence of LBW compared with nonuse (8.1% vs 6.1%; adjusted prevalence ratio 1.33; 95% CI 1.06-1.66). Among respondents who did not also smoke combustible cigarettes during pregnancy (n=72,256), e-cigarette use was associated with higher prevalence of LBW (10.6%; adjusted prevalence ratio 1.88; 95% CI 1.38-2.57) and preterm birth (12.4%; adjusted prevalence ratio 1.69; 95% CI 1.20-2.39). When further stratified by frequency of e-cigarette use, associations were seen only for daily users.

CONCLUSION

E-cigarette use during pregnancy, particularly when used daily by individuals who do not also smoke combustible cigarettes, is associated with adverse birth outcomes.

Patterns of combustible and electronic cigarette use during pregnancy and associated pregnancy outcomes

Although pregnant smokers may perceive electronic cigarettes (e-cigarettes) as safe alternatives to smoking combustible cigarettes, few studies have evaluated perinatal e-cigarette use and its associated health effects. We analyzed data from the Pregnancy Risk Assessment Monitoring System (PRAMS, 2016-2018) for 16,022 women who recently gave birth and reported smoking combustible cigarettes prior to pregnancy. Using average marginal predictive values from multivariable logistic regression to produce adjusted prevalence ratios (aPRs), we estimated the prevalence of combustible cigarette smoking during pregnancy and adverse birth outcomes associated with e-cigarette use. In total, 14.8% of smoking women reported using e-cigarettes prior to pregnancy. There was no association between e-cigarette use prior to pregnancy and combustible cigarette smoking during pregnancy (aPR 0.95; 95% CI 0.88, 1.02); however, e-cigarette use during pregnancy was associated with higher prevalence of combustible cigarette smoking during pregnancy (aPR 1.65; 95% CI 1.52, 1.80). In this sample, we did not observe evidence to support reduced risk of preterm birth, small-for-gestational age and low birthweight compared to combustible cigarette smoking during pregnancy. The prevalence of LBW was higher for those who used e-cigarettes, even exclusively, compared to women who quit smoking cigarettes entirely. These results suggest that e-cigarettes should not be considered a safe alternative to combustible cigarette smoking during pregnancy.

Long-term cerebrovascular dysfunction in the offspring from maternal electronic cigarette use during pregnancy

Electronic cigarettes (E-cigs) have been promoted as harm-free or less risky than smoking, even for women during pregnancy. These claims are made largely on E-cig aerosol having fewer number of toxic chemicals compared with cigarette smoke. Given that even low levels of smoking are found to produce adverse birth outcomes, we sought to test the hypothesis that vaping during pregnancy (with or without nicotine) would not be harm-free and would result in vascular dysfunction that would be evident in offspring during adolescent and/or adult life. Pregnant female Sprague Dawley rats were exposed to E-cig aerosol (1 h/day, 5 days/wk, starting on gestational day 2 until pups were weaned) using e-liquid with 0 mg/mL (E-cig0) or 18 mg/mL nicotine (E-cig18) and compared with ambient air-exposed controls. Body mass at birth and at weaning were not different between groups. Assessment of middle cerebral artery (MCA) reactivity revealed a 51%-56% reduction in endothelial-dependent dilation response to acetylcholine (ACh) for both E-cig0 and E-cig18 in 1-mo, 3-mo (adolescent), and 7-mo-old (adult) offspring (P < 0.05 compared with air, all time points). MCA responses to sodium nitroprusside (SNP) and myogenic tone were not different across groups, suggesting that endothelial-independent responses were not altered. The MCA vasoconstrictor response (5-hydroxytryptamine, 5-HT) was also not different across treatment and age groups. These data demonstrate that maternal vaping during pregnancy is not harm-free and confers significant cerebrovascular health risk/dysfunction to offspring that persists into adult life. NEW & NOTEWORTHY These data established that vaping electronic cigarettes during pregnancy, with or without nicotine, is not safe and confers significant risk potential to the cerebrovascular health of offspring in early and adult life. A key finding is that vaping without nicotine does not protect offspring from cerebrovascular dysfunction and results in the same level of cerebrovascular dysfunction (compared with maternal vaping with nicotine), indicating that the physical and/or chemical properties from the base solution (other than nicotine) are responsible for the cerebrovascular dysfunction that we observed. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/maternal-vaping-impairs-vascular-function-in-theoffspring/.

Vaping Exacerbates Coronavirus-Related Pulmonary Infection in a Murine Model

Though the current preponderance of evidence indicates the toxicity associated with the smoking of tobacco products through conventional means, less is known about the role of "vaping" in respiratory disease. "Vaping" is described as the use of electronic cigarettes (E-Cigarettes or E-Cigs), which has only more recently been available to the public (∼10 years) but has quickly emerged as a popular means of tobacco consumption worldwide. The World Health Organization (WHO) declared the SARS-CoV-2 outbreak as a global pandemic in March 2020. SARS-CoV-2 can easily be transmitted between people in close proximity through direct contact or respiratory droplets to develop coronavirus infectious disease 2019 (COVID-19). Symptoms of COVID-19 range from a mild flu-like illness with high fever to severe respiratory distress syndrome and death. The risk factors for increased disease severity remain unclear. Herein, we utilize a murine-tropic coronavirus (beta coronavirus) MHV-A59 along with a mouse model and measures of pathology (lung weight/dry ratios and histopathology) and inflammation (ELISAs and cytokine array panels) to examine whether vaping may exacerbate the pulmonary disease severity of coronavirus disease. While vaping alone did result in some noted pathology, mice exposed with intranasal vaped e-liquid suffered more severe mortality due to pulmonary inflammation than controls when exposed to coronavirus infection. Our data suggest a role for vaping in increased coronavirus pulmonary disease in a mouse model. Furthermore, our data indicate that disease exacerbation may involve calcium (Ca2+) dysregulation, identifying a potential therapeutic intervention.

Sex dependent effect of maternal e-nicotine on F1 Drosophila development and airways

E-cigarettes are heavily advertised as healthier alternative to common tobacco cigarettes, leading more and more women to switch from regular cigarettes to ENDS (electronic nicotine delivery system) during pregnancy. While the noxious consequences of tobacco smoking during pregnancy on the offspring health are well-described, information on the long-term consequences due to maternal use of e-cigarettes do not exist so far. Therefore, we aimed to investigate how maternal e-nicotine influences offspring development from earliest life until adulthood. To this end, virgin female Drosophila melanogaster flies were exposed to nicotine vapor (8 µg nicotine) once per hour for a total of eight times. Following the last exposure, e-nicotine or sham exposed females were mated with non-exposed males. The F1-generation was then analyzed for viability, growth and airway structure. We demonstrate that maternal exposure to e-nicotine not only leads to reduced maternal fertility, but also negatively affects size and weight, as well as tracheal development of the F1-generation, lasting from embryonic stage until adulthood. These results not only underline the need for studies investigating the effects of maternal vaping on offspring health, but also propose our established model for analyzing molecular mechanisms and signaling pathways mediating these intergenerational changes.

JUUL e-liquid exposure elicits cytoplasmic Ca2+ responses and leads to cytotoxicity in cultured airway epithelial cells

RATIONALE

The popularity of new and emerging tobacco products such as E-cigarettes (E-cigs) is rapidly expanding worldwide. However, uncertainties surrounding the potential health consequences due to the use of such products exist and warrant further study.

METHODS

Cultured A549 and Calu-3 airway epithelia were exposed to three out of the eight types of JUUL brand e-liquids ("Mint", "Virginia Tobacco" and "Menthol", all containing 3% nicotine at 1% and 3% (vol/vol) dilutions) and assessed for viability using a resazurin-based assay. Intracellular Ca2+ levels were measured using fluorescent indicators and pro-inflammatory cytokine levels were monitored by quantitative PCR (qPCR). Cultures were also analyzed by flow cytometry to evaluate apoptotic markers and cell viability.

RESULTS

Exposing the airway epithelial cells to the flavored JUUL e-liquids led to significant cytotoxicity, with the "Mint" flavor being the overall most cytotoxic. The "Mint" flavored e-liquid also led to significant elevations in intracellular Ca2+ and upregulation of the pro-inflammatory cytokine IL-6 and early apoptotic marker Annexin V.

CONCLUSIONS

JUUL e-liquid challenge resulted in a loss of airway epithelial cell viability, induced pro-inflammatory responses and eventually caused apoptosis.

Cigarette Smoke Extract Activates Hypoxia-Inducible Factors in a Reactive Oxygen Species-Dependent Manner in Stroma Cells from Human Endometrium

Cigarette smoking (CS) is a major contributing factor in the development of a large number of fatal and debilitating disorders, including degenerative diseases and cancers. Smoking and passive smoking also affect the establishment and maintenance of pregnancy. However, to the best of our knowledge, the effects of smoking on the human endometrium remain poorly understood. In this study, we investigated the regulatory mechanism underlying CS-induced hypoxia-inducible factor (HIF)-1α activation using primary human endometrial stromal cells and an immortalized cell line (KC02-44D). We found that the CS extract (CSE) increased reactive oxygen species levels and stimulated HIF-1α protein stabilization in endometrial stromal cells, and that CS-induced HIF-1α-dependent gene expression under non-hypoxic conditions in a concentration- and time-dependent manner. Additionally, we revealed the upregulated expression of a hypoxia-induced gene set following the CSE treatment, even under normoxic conditions. These results indicated that HIF-1α might play an important role in CS-exposure-induced cellular stress, inflammation, and endometrial remodeling.

Whole body electronic cigarette exposure system for efficient evaluation of diverse inhalation conditions and products

Objectives: To develop and test a new system for whole body exposure of small animals to support investigation of the biological effects of aerosol generated by electronic cigarette (e-cig) products under diverse inhalation conditions with improved control and monitoring of the e-cig vape exposure and nicotine delivered to the animal's systemic circulation. Methods: A computer-controlled design, with built-in sensors for real time monitoring of O₂, CO₂, relative humidity, and temperature within the exposure chambers and port for measuring total particulate matter (TPM) was developed, constructed and tested. This design accommodates a variety of commercial vaping devices, offers software flexibility to adjust exposure protocols to mimic different users' puffing patterns, enables variable nicotine delivery to the animal's systemic circulation; minimizes travel time and alterations of aerosol quality or quantity by delivering aerosol directly to the exposure chamber, offers local or remote operation of up to six distinct exposure chambers from a single control unit, and can simultaneously test different exposure conditions or products in diverse animal groups, which reduces inter-run variability, saves time, and increases productivity. Results: The time course pattern of TPM concentration during different phases of the exposure cycle was measured. With increased puffing duration or number of exposure cycles, higher TPM exposure and plasma cotinine levels were observed with plasma cotinine levels in the range reported in light or heavy smokers. Conclusion: Overall, this novel, versatile, and durable exposure system facilitates high-throughput evaluation of the relative safety and potential toxicity of a variety of e-cig devices and liquids.

Early Cardiovascular Risk in E-cigarette Users: the Potential Role of Metals

PURPOSE OF REVIEW

Electronic cigarettes (e-cigs) are a source of metals. Epidemiologic and experimental evidence support that metals are toxic to the cardiovascular system. Little is known, however, about the role that e-cig metals may play as toxicants for the possible cardiovascular effects of e-cig use. The goal of this narrative review is to summarize the evidence on e-cig use and metal exposure and on e-cig use and cardiovascular toxicity and discuss the research needs.

RECENT FINDINGS

In vitro studies show cytotoxicity and increased oxidative stress in myocardial cells and vascular endothelial cells exposed to e-liquids and e-cig aerosols, with effects partially reversed with antioxidant treatment. There is some evidence that the heating coil plays a role in cell toxicity. Mice exposed to e-cigs for several weeks showed higher levels of oxidative stress, inflammation, platelet activation, and thrombogenesis. Cross-over clinical experiments show e-cig use alters nitric oxide-mediated flow-mediated dilation, endothelial progenitor cells, and arterial stiffness. Cross-sectional evidence from large nationally representative samples in the USA support that e-cig use is associated with self-reported myocardial infarction. Smaller studies found associations of e-cig use with higher oxidized low-density protein and heart variability compared to healthy controls. Numerous studies have measured elevated levels of toxic metals in e-cig aerosols including lead, nickel, chromium, and manganese. Arsenic has been measured in some e-liquids. Several of these metals are well known to be cardiotoxic. Numerous studies show that e-cigs are a source of cardiotoxic metals. Experimental studies (in vitro, in vivo, and clinical studies) show acute toxicity of e-cigs to the vascular system. Studies of long-term toxicity in animals and humans are missing. Longitudinal studies with repeated measures of metal exposure and subclinical cardiovascular outcomes (e.g., coronary artery calcification) could contribute to determine the long-term cardiovascular effects of e-cigs and the potential role of metals in those effects.

Electronic cigarettes — myocardial infarction, hemodynamic compromise during pregnancy, and systolic and diastolic dysfunction: Minireview

The aim of this study was to review the most recent literature on the safety of electronic cigarettes (ECs) in the context of cardiovascular disease and in the context as a tool for smoking cessation and recreational purposes. The format of this review begins with relevant research from the basic sciences and follows through with a pertinent review of clinical trials. Daily use of ECs has implications in myocardial infarction (MI) with an odds ratio of 1.70 compared to healthy, nonsmokers and even worse risk for MI with dual use of combustible cigarettes together with EC with an odds ratio of 4.62. Studies measuring cardiac function with echocardiography reported both systolic and diastolic dysfunction along with reduced ejection fractions. Platelet aggregation, endothelial function, and hemodynamics during pregnancy were all but some of the pernicious cardiovascular implications of EC exposure. Though more studies need to be done on the topic of EC use and cardiovascular disease, the majority of studies considered in this review concluded some level of harm albeit in some instances less than that of traditional combustible cigarettes. ECs are toxic to human beings and their harmful effects cannot be overlooked. There is some favorable evidence of efficacy in smoking cessation though mixed with concern of chronic EC use. It will take decades to collect data for chronic EC use on long term sequelae, such as lung cancer. Though more and more reports of acute lung injury and hospitalizations related to EC use have been reported. Due to undergoing investigations of possible harm and life threatening complications of EC use, we cannot recommend ECs as safer or a more efficacious method of smoking cessation to traditional nicotine replacement therapies. A notable consideration for much of the literature reviewed are that standardization of EC use is difficult as device generation and battery voltage, frequency of use, and contents of EC liquid are just some of the vast complicating factors that limit the ability to effectively compare data.

Changes in Multiple and Different Tobacco Product Use Behaviors in Women Before and During Pregnancy: An Analysis of Longitudinal Population Assessment of Tobacco and Health Data

INTRODUCTION

Changes in tobacco use behaviors among women with respect to pregnancy are expected to be significant and dynamic, with a strong desire for smoking cessation, diversification of tobacco products, and perceived relative safety on noncigarette tobacco products. This study aims to illustrate how multiple and different tobacco use behaviors change before and during pregnancy.

METHODS

Data were extracted from 864 pregnant, nationally representative U.S. women, who were prospectively followed with the Population Assessment of Tobacco and Health study between 2013 and 2017. Smoking statuses were defined on the basis of the number and type of 7 different tobacco products under current use. Differences in maternal characteristics were investigated in relation to tobacco cessation statuses during pregnancy. Weighted percentages and 95% CIs were calculated.

RESULTS

Only 50.4% of prepregnancy tobacco users achieved complete abstinence with varying rates of cessation, depending on the number and type of products used prepregnancy. The lowest cessation rates were observed among prepregnancy poly-tobacco users (23.3%) and conventional cigarette smokers (45.5%). During pregnancy, 11.3% and 2.8% of women reported smoking cigarettes and e-cigarettes, respectively. Persistent tobacco users during pregnancy were more likely to be white, be older, and have nonprivate or no medical insurance (all p<0.05).

CONCLUSIONS

This study demonstrates a widespread prenatal tobacco use and low rates of complete cessation in major subgroups of tobacco users. Current findings on the concurrent use of multiple products and noncigarette tobacco products highlight the urgent need for further research and comprehensive public health intervention for smoking cessation during pregnancy.

Electronic cigarettes may not be a "safer alternative" of conventional cigarettes during pregnancy: evidence from the nationally representative PRAMS data

Background

Conventional cigarette (CC) smoking is one of the most preventable causes of adverse birth outcomes. Although electronic cigarettes (ECs) are considered to be safer than CCs during pregnancy, the evidence is yet to be presented. This study examines the effects of prenatal EC use on neonatal birth outcomes compared to those of CC smokers and complete tobacco abstainers.

Methods

Data was extracted from 55,251 pregnant women who participated in the Phase 8 survey of the Pregnancy Risk Assessment Monitoring System between 2016 and 2018. Participants were classified into three groups based on their smoking behaviors in the third trimester: complete tobacco abstinence, exclusive CC smoking, or exclusive EC use. Adverse outcomes included infants being small-for-gestational-age (SGA), having low birthweight (LBW), and being born at preterm. EC users were matched to complete abstainers and CC smokers who share the same baseline characteristics in race/ethnicity, age, educational attainment, income, prenatal care adequacy, and first- and second-trimester CC smoking statuses. The association between EC use and adverse birth outcomes were examined by survey-weighted logistic regression analyses in the matched population.

Results

Among participants, 1.0% of women reported having used ECs during the third trimester, 60% of which reported using ECs exclusively. Neonates of EC users were significantly more likely to be SGA (OR 1.76; 95% CI 1.04, 2.96), have LBW (OR 1.53; 95% CI 1.06, 2.22), or be born preterm (OR 1.86; 95% CI 1.11, 3.12) compared to tobacco abstainers. However, odds of EC users’ pregnancies resulting in SGA (OR 0.67; 95% CI 0.30, 1.47), LBW (OR 0.71; 95% CI 0.37, 1.37), or preterm birth (OR 1.06; 95% CI 0.46, 2.48) were not significantly lower than those of CC smokers.

Conclusions

Even after accounting for shared risk factors between prenatal tobacco use and adverse birth outcomes, EC use remains an independent risk factor for neonatal complications and is not a safer alternative to CC smoking during pregnancy. Until further research is completed, all pregnant women are encouraged to abstain from all tobacco products including ECs.

Tobacco Smoke and Endothelial Dysfunction: Role of Aldehydes?

PURPOSE OF REVIEW

Tobacco smoking is the most significant modifiable risk factor in the development of cardiovascular disease (CVD). Exposure to mainstream cigarette smoke (MCS) is associated with CVD through the development of endothelial dysfunction, a condition characterized by an imbalance of vasoactive factors in the vasculature. This dysfunction is thought to be induced in part by aldehydes generated at high levels in MCS.

RECENT FINDINGS

Electronic cigarettes (e-cigs) may also pose CVD risk. Although the health effects of e-cigs are still largely unknown, the presence of aldehydes in e-cig aerosol suggests that e-cigs may induce adverse cardiovascular outcomes similar to those seen with MCS exposure. Herein, we review studies of traditional and emerging tobacco product use, shared harmful and potentially harmful constituents, and measures of biomarkers of harm (endothelial dysfunction) to examine a potential and distinct role of aldehydes in cardiovascular harm associated with cigarette and e-cig use.

The Effects of E-Cigarette Vapor Components on the Morphology and Function of the Male and Female Reproductive Systems: A Systematic Review

E-cigarettes, a comparatively new phenomenon, are regarded as a safer alternative to conventional cigarettes. They are increasingly popular among adolescents of both sexes, and many smokers use e-cigarettes in their attempts to quit smoking. There is little understanding of the effects of exposure to e-cigarette vapors on human reproductive health, human development, or the functioning of the organs of the male and female reproductive systems. Data on the effects of the exposure were derived mainly from animal studies, and they show that e-cigarettes can affect fertility. Here, we review recent studies on the effects of exposure to e-cigarettes on facets of morphology and function in the male and female reproductive organs. E-cigarettes, even those which are nicotine-free, contain many harmful substances, including endocrine disruptors, which disturb hormonal balance and morphology and the function of the reproductive organs. E-cigarettes cannot be considered a completely healthy alternative to smoking. As is true for smoking, deleterious effects on the human reproductive system from vaping are likely, from the limited evidence to date.

Could E-cigarette vaping contribute to heart disease?

INTRODUCTION

E-cigarettes have become a controversial topic. While their benefits are questioned by the scientific community, a part of the medical profession is still supporting them as an effective harm reduction tool for smoking cessation. The impact of E-cigarettes on the cardiovascular system is still elusive.

AREAS COVERED

We assessed results from animal, pre(clinical), and epidemiological studies to critically evaluate and synthesize evidence relevant to the cardiovascular effects of E-cigarettes. Animal studies have demonstrated that E-cigarette vapor exposure can cause endothelial and cardiac dysfunction. However, there have also been reports on the less harmful effects of E-cigarette vapor exposure in comparison to classical tobacco cigarettes. Measurements of flow-mediated dilation in acute human exposure settings have mostly demonstrated that E-cigarettes cause vascular endothelial dysfunction. Epidemiological studies have shown that E-cigarette use is associated with an increased risk for cardiovascular disease, although switching from classical tobacco cigarettes to E-cigarettes can have beneficial cardiovascular effects. Misinterpretation of scientific data by activists on either side is another problem.

EXPERT OPINION

In conclusion, we need more and better (pre)clinical data comparing the health effects of E-cigarette vaping as compared with tobacco cigarette smoking, in order to counsel the legislation for better health policies.

World vaping update

PURPOSE OF REVIEW

Although death and injury related to e-cigarette use and vaping products has decreased since the peak in 2019, concern over the popularity of electronic nicotine delivery systems (ENDS - a term which includes vape pens, electronic or e-cigarettes, and products that produce vapor for inhaling rather than combusting to produce smoke) continues. ENDS are used as an aid to quit smoking and for harm reduction.

RECENT FINDINGS

This review covers peer-reviewed literature from January 2019 through February 2020 on vaping (the process of using ENDS). Prevalence, risk factors for use, and health risks and benefits from use predominated. Policy articles, commentaries and editorials were excluded from review. E-cigarette or vaping product use-associated lung injury (EVALI)-related injury and death were in the news and literature this year. Because most EVALI-related injury and death occurred among young people who had vaped tetrahydrocannabinol (THC), data from the Healthy Minds (United States) study are reviewed to consider variation in risk factors for vaping THC compared with nicotine.

SUMMARY

Findings provide up-to-date information on vaping as a way to consume a drug, whether THC or nicotine. Harm reduction benefits were shown in a year-long follow-up of smoking cessation; harms continue to accumulate, including from passive consumption.

Recent findings in the pharmacology of inhaled nicotine: Preclinical and clinical in vivo studies

INTRODUCTION

The rise of vaping in adolescents, the recent entrance of new inhaled nicotine products such as iQOS on the market and e-cigarette or vaping product use-associated lung injury cases has created concern for the use of inhaled non-combustible nicotine products. This narrative review discusses recent experimental in vivo studies that utilize human, rat and mouse models to understand the pharmacological impact of nicotine from non-combustible products.

METHODS

The search engine PubMed was utilized with the following search terms: inhaled nicotine, nicotine e-cigarette, heated tobacco products, iQOS, electronic cigarette, nicotine inhaler, nicotine vaping. This review highlights recent primary in vivo studies of inhaled nicotine administration experimental paradigms that occurred in laboratory settings using human and rodent (rats and mice) models that have been published from January 2017-December 2019.

RESULTS

The pharmacokinetics of nicotine via e-cigarettes is influenced by the PG/VG and flavor constituents in e-liquids, the presence of nicotine salts in e-liquids, puff topography of nicotine and tobacco product users and the power of the e-cigarette device. The pharmacodynamic impact of inhaled nicotine has cardiovascular, pulmonary and central nervous system implications.

CONCLUSION

The articles reviewed here highlight the importance of both animal and human models to fully understand the impact of inhaled nicotine pharmacology There is a need for more rodent pharmacokinetic inhaled nicotine studies to understand the influences of factors such as flavor and nicotine salts. Additionally, consensus on nicotine measurement in both human and rodent studies is greatly needed.

Neurotoxicity of e-cigarettes

It appears that electronic cigarettes (EC) are a less harmful alternative to conventional cigarette (CC) smoking, as they generate substantially lower levels of harmful carcinogens and other toxic compounds. Thus, switching from CC to EC may be beneficial for smokers. However, recent accounts of EC- or vaping-associated lung injury (EVALI) has raised concerns regarding their adverse health effects. Additionally, the increasing popularity of EC among vulnerable populations, such as adolescents and pregnant women, calls for further EC safety evaluation. In this state-of-the-art review, we provide an update on recent findings regarding the neurological effects induced by EC exposure. Moreover, we discuss possible neurotoxic effects of nicotine and numerous other chemicals which are inherent both to e-liquids and EC aerosols. We conclude that in recognizing pertinent issues associated with EC usage, both government and scientific researchers must address this public health issue with utmost urgency.

In utero exposures to electronic-cigarette aerosols impair the Wnt signaling during mouse lung development

Currently, more than 9 million American adults, including women of childbearing age, use electronic-cigarettes (e-cigs). Further, the prevalence of maternal vaping now approaching 10% is similar to that of maternal smoking. Little, however, is known about the effects of fetal exposures to nicotine-rich e-cig aerosols on lung development. In this study, we assessed whether in utero exposures to e-cig aerosols compromised lung development in mice. A third-generation e-cig device was used to expose pregnant BALB/c mice by inhalation to 36 mg/mL of nicotine cinnamon-flavored e-cig aerosols for 14-31 days. This included exposures for either 12 days before mating plus during gestation (preconception groups) or only during gestation (prenatal groups). Respective control mice were exposed to filtered air. Subgroups of offspring were euthanized at birth or at 4 wk of age. Compared with respective air-exposed controls, both preconception and prenatal exposures to e-cig aerosols significantly decreased the offspring birth weight and body length. In the preconception group, 7 inflammation-related genes were downregulated, including 4 genes common to both dams and fetuses, denoting an e-cig immunosuppressive effect. Lung morphometry assessments of preconception e-cig-exposed offspring showed a significantly increased tissue fraction at birth. This result was supported by the downregulation of 75 lung genes involved in the Wnt signaling, which is essential to lung organogenesis. Thus, our data indicate that maternal vaping impairs pregnancy outcomes, alters fetal lung structure, and dysregulates the Wnt signaling. This study provides experimental evidence for future regulations of e-cig products for pregnant women and developmentally vulnerable populations.

Is vaping better than smoking for cardiorespiratory and muscle function?

Cigarette smoking is a risk factor for respiratory disorders, cardiovascular diseases and even decrements in muscle function. Electronic cigarette use (vaping) is considered a healthier alternative to cigarette smoking and may help in smoking cessation. However, the effects of vaping are not clear yet and particularly the long-term effects of vaping are largely unknown. Some reports suggest that vaping maybe as harmful for e.g. respiratory function, as cigarette smoking. In this narrative review the effects of vaping and cigarette smoking on respiratory, cardiovascular and muscle function are compared. Overall, vaping has been found to cause similar effects as smoking on lung function and cardiovascular function. Future studies are needed to clarify the severity of smoking- and vaping-induced decrements on muscle function.

Smoking and pregnancy: The era of electronic nicotine delivery systems

Electronic nicotine delivery systems have been commercially available in the United States since 2007. Despite a decrease in combustible cigarette use, electronic nicotine delivery systems use has dramatically increased among both adults and adolescents. These devices have been marketed as smoking cessation aids, although data on their efficacy are scarce. Pregnant women are an especially vulnerable population susceptible to claims of safety and efficacy, and the medical community remains inadequately informed on how to counsel these women. The purpose of this article is to review known literature regarding the use of electronic nicotine delivery systems in pregnancy, to understand the differences between cigarettes and electronic nicotine delivery systems use in pregnancy, and to further guide clinicians on how to advise the pregnant woman on their use.

Comparison of Protective Effects of Electroacupuncture at ST 36 and LU 5 on Pulmonary and Hypothalamic Pituitary Adrenal Axis Changes in Perinatal Nicotine-Exposed Rats

BACKGROUND

Maternal smoking and/or exposure to environmental tobacco smoke continue to be significant factors in fetal and childhood morbidity and are a serious public health issue worldwide. Nicotine passes through the placenta easily with minimal biotransformation, entering fetal circulation, where it results in many harmful effects on the developing offspring, especially on the developing respiratory system.

OBJECTIVES

Recently, in a rat model, electroacupuncture (EA) at maternal acupoints ST 36 has been shown to block perinatal nicotine-induced pulmonary damage; however, the underlying mechanism and the specificity of ST 36 acupoints for this effect are unknown. Here, we tested the hypothesis that compared with EA at ST 36, EA at LU 5 acupoints, which are on lung-specific meridian, will be equally or more effective in preventing perinatal nicotine-induced pulmonary changes.

METHODS

Twenty-four pregnant rat dams were randomly divided into 4 groups: saline ("S"), nicotine ("N"), nicotine + ST 36 (N + ST 36), and nicotine + LU 5 (N + LU 5) groups. Nicotine (1 mg/kg, subcutaneously) and EA (at ST 36 or LU 5 acupoints, bilaterally) were administered from embryonic day 6 to postnatal day 21 once daily. The "S" group was injected saline. As needed, using ELISA, western analysis, q-RT-PCR, lung histopathology, maternal and offspring hypothalamic pituitary adrenal axes, offspring key lung developmental markers, and lung morphometry were determined.

RESULTS

With nicotine exposure, alveolar count decreased, but mean linear intercept and septal thickness increased. It also led to a decrease in pulmonary function and PPARγ and an increase of β-catenin and glucocorticoid receptor expression in lung tissue and corticosterone in the serum of offspring rats. Electroacupuncture at ST 36 normalized all of these changes, whereas EA at LU 5 had no obvious effect.

CONCLUSION

Electroacupuncture applied to ST 36 acupoints provided effective protection against perinatal nicotine-induced lung changes, whereas EA applied at LU 5 acupoints was ineffective, suggesting mechanistic specificity and HPA axis' involvement in mediating EA at ST 36 acupoints' effects in mitigating perinatal nicotine-induced pulmonary phenotype. This opens the possibility that other acupoints, besides ST 36, can have similar or even more robust beneficial effects on the developing lung against the harmful effect of perinatal nicotine exposure. The approach proposed by us is simple, cheap, quick, easy to administer, and is devoid of any significant side effects.

Electronic nicotine delivery systems and pregnancy: Recent research on perceptions, cessation, and toxicant delivery

Electronic nicotine delivery systems (ENDS), which includes e-cigarettes (ECIGs), are a rapidly-expanding class of products that heat a liquid (which may or may not contain nicotine) to produce an aerosol. The variation of ECIG components is extensive as are their effects on users. Epidemiological data show that while both adults and youth use ECIGs, use among youth has increased dramatically in recent years. Other epidemiological data show that women of reproductive age and some pregnant women are also using ECIGs. The goal of this article is to provide readers with background information about ECIGs, with a focus on recent findings about ECIG use in pregnancy and potential implications. Among pregnant women, correlates of ECIG use include current cigarette smoking, among other factors. Regarding pregnant women's perceptions of ECIG use in pregnancy, two themes emerge from the literature: many pregnant women perceive ECIGs to be safer than conventional cigarettes, and that ECIGs can aid with smoking cessation. In contrast to these perceptions, there is little concrete evidence that ECIGs help smokers quit. In addition, there are concerns about ECIG nicotine and other toxicant delivery. Nicotine is a toxicant of particular concern for pregnant women, as nicotine is known to harm a developing fetus. There are many limitations to existing research, and the literature is scant in this area. Further, new "pod mod"-style ECIGs such as JUUL present new challenges. Overall, with limited evidence of their effectiveness, and concerns about developmental toxicology, the authors do not recommend that pregnant women use ECIGs.

Modeling drug exposure in rodents using e-cigarettes and other electronic nicotine delivery systems

Smoking tobacco products is the leading cause of preventable death worldwide. Coordinated efforts have successfully reduced tobacco cigarette smoking in the United States; however, electronic cigarettes (e-cigarette) and other electronic nicotine delivery systems (ENDS) recently have replaced traditional cigarettes for many users. While the clinical risks associated with long-term ENDS use remain unclear, advancements in preclinical rodent models will enhance our understanding of their overall health effects. This review examines the peripheral and central effects of ENDS-mediated exposure to nicotine and other drugs of abuse in rodents and evaluates current techniques for implementing ENDS in preclinical research.

Impact of Electronic Cigarette Aerosols on Pregnancy and Early Development

As the use of electronic cigarettes (e-cigs) continues to increase, especially among youth and pregnant women, so does the need for investigations into the effects of e-cig aerosols on prenatal development and early life. Herein, the most recent findings on the effects of e-cig aerosols during pregnancy and early life are reviewed. The results of these studies support the need for immediate action to further understand the potential harm that e-cigs may cause to pregnant women and their children. The effects of e-cigs is completely unknown in regards to human development. This review provides evidence that e-cigs may be harmful to early life development and that the use of e-cigs should be avoided during pregnancy.