The Use of Electronic Cigarettes in Pregnancy: A Review of the Literature

Vaping during pregnancy: a systematic review of health outcomes

INTRODUCTION

Smoking during pregnancy is harmful to maternal and child health. Vaping is used for smoking cessation but evidence on health effects during pregnancy is scarce. We conducted a systematic review of health outcomes of vaping during pregnancy.

METHODS

We searched six databases for maternal/fetal/infant outcomes and vaping, including quantitative, English language, human studies of vaping during pregnancy, to November 10th, 2023. We assessed study quality with the Mixed-Methods Appraisal Tool. We focused on comparisons of exclusive-vaping with non-use of nicotine and tobacco products and with smoking. Presentation is narrative as the studies were of insufficient quality to conduct meta-analysis.

RESULTS

We included 26 studies, with 765,527 women, with one randomised controlled trial (RCT) comparing vaping and nicotine replacement therapy for smoking cessation, 23 cohort studies and two case-control studies. While the RCT met 4/5 quality criteria, the quality of the cohort studies and case-control studies was poor; none adequately assessed exposure to smoking and vaping. For studies comparing exclusive-vaping with 'non-use', more reported no increased risk for vaping (three studies) than reported increased risk for maternal pregnancy/postpartum outcomes (one study) and for fetal and infant outcomes (20 studies no increased risk, four increased risk), except for birth-weight and neurological outcomes where two studies each observed increased and no increased risk. When the RCT compared non-users with those not smoking but vaping or using NRT, irrespective of randomisation, they reported no evidence of risk for vaping/NRT. For studies comparing exclusive-vaping and exclusive-smoking, most studies provided evidence for a comparable risk for different outcomes. One maternal biomarker study revealed a lower risk for vaping. For small-for-gestational-age/mean-birth-centile equal numbers of studies found lower risk for vaping than for smoking as found similar risk for the two groups (two each).

CONCLUSIONS

While more studies found no evidence of increased risk of exclusive-vaping compared with non-use and evidence of comparable risk for exclusive-vaping and exclusive-smoking, the quality of the evidence limits conclusions. Without adequate assessment of exposure to vaping and smoking, findings cannot be attributed to behaviour as many who vape will have smoked and many who vape may do so at low levels.

STUDY REGISTRATION

https://osf.io/rfx4q/ .

Inter- and trans-generational impacts of environmental exposures on the germline resolved at the single-cell level

Reproduction is a remarkably intricate process involving the interaction of multiple cell types and organ systems unfolding over long periods of time and that culminates with the production of gametes. The initiation of germ cell development takes place during embryogenesis but only completes decades later in humans. The complexity inherent to reproduction and its study has long hampered our ability to decipher how environmental agents disrupt this process. Single-cell approaches provide an opportunity for a deeper understanding of the action of toxicants on germline function and analyze how the response to their exposure is differentially distributed across tissues and cell types. In addition to single-cell RNA sequencing, other single-cell or nucleus level approaches such as ATAC-sequencing and multi-omics have expanded the strategies that can be implemented in reproductive toxicological studies to include epigenomic and the nuclear transcriptomic data. Here we will discuss the current state of single-cell technologies and how they can best be utilized to advance reproductive toxicological studies. We will then discuss case studies in two model organisms (Caenorhabditis elegans and mouse) studying different environmental exposures (alcohol and e-cigarettes respectively) to highlight the value of single-cell and single-nucleus approaches for reproductive biology and reproductive toxicology.

Vaporized nicotine in utero results in reduced birthweight, increased locomotion, and decreased voluntary exercise, dependent on sex and diet in offspring

Rationale Clinical research has shown that prenatal exposure to nicotine may result in increased obesity risk later in life. Preclinical research has corroborated this finding, but few studies have investigated inhaled nicotine or the interaction with diet on obesity risk. Objective The aim of this study was to investigate the effects of prenatal nicotine exposure on both direct and indirect obesity measures, with both sex and diet as factors. Methods Pregnant rats were exposed to either vehicle or nicotine vapor (24 mg/mL or 59 mg/mL) throughout the entire gestational period. Offspring from each treatment group were given either a normal diet or a high fat diet starting at postnatal day 22. Caloric intake, body weight, spontaneous locomotion, sleep/wake activity, and voluntary exercise were measured throughout adolescence. Pregnancy weight gain and pup birthweights were collected to further measure developmental effects of prenatal nicotine exposure. Results Both maternal weight gain during pregnancy and pup weight at birth were decreased with prenatal nicotine exposure. Early adolescent males showed increased spontaneous activity in the open field following prenatal nicotine exposure compared to vehicle counterparts, particularly those given high-fat diet. Additionally, high dose nicotine prenatal treated males ran significantly less distance on the running wheel in late adolescence compared to vehicle counterparts, in the normal diet group only. Conclusion The results presented here show decreased birthweight, hyperactivity, and decreased voluntary exercise in adolescence following prenatal nicotine exposure in dose, sex, and diet dependent manners, which could lead to increased obesity risk in adulthood.

Tobacco or marijuana use and infertility: a committee opinion

In the United States, approximately 21% of adults report some form of tobacco use, although 18% report marijuana use. Although the negative impact of tobacco use in pregnancy is well documented, the impact of tobacco and marijuana on fertility and reproduction is less clear. This committee opinion reviews the potential deleterious effects of tobacco, nicotine, and marijuana use on conception, ovarian follicular dynamics, sperm parameters, gamete mutations, early pregnancy, and assisted reproductive technology outcomes. It also reviews the current status of tobacco smoking cessation strategies. This document replaces the 2018 American Society for Reproductive Medicine Practice Committee document entitled Smoking and Infertility: a committee opinion (Fertil Steril 2018).

Low levels of nicotine and cotinine but not benzo[a]pyrene induce human trophoblast cell proliferation

E-cigarettes use constitutes a source of thirdhand nicotine exposure. The increasing use of electronic cigarettes in homes and public places increases the risk of exposure of pregnant women to thirdhand nicotine. The effects of exposure of pregnant women to very low levels of nicotine have not been studied in humans but detrimental in experimental animals. The objective of this study is to investigate the effect of nanomolar concentrations of nicotine and its metabolite cotinine on the proliferation of JEG-3, a human trophoblast cell line. We also studied the proliferative effect of nanomolar concentrations of benzo[a]pyrene (B[a]P), a polycyclic hydrocarbon in tobacco smoke, for comparison. We treated JEG-3 cells in culture with nanomolar concentrations of nicotine, cotinine, and B[a]P. Their effect on cell proliferation was determined, relative to untreated cells, by MTT assay. Western blotting was used to assess the mitogenic signaling pathways affected by nicotine and cotinine. In contrast to the inhibitory effects reported with higher concentrations, we showed that nanomolar concentrations of nicotine and cotinine resulted in significant JEG-3 cell proliferation and a rapid but transient increase in levels of phosphorylated ERK and AKT, but not STAT3. Biphasic, non-monotonic effect on cell growth is characteristic of endocrine disruptive chemicals like nicotine. The mitogenic effects of nicotine and cotinine potentially contribute to increased villous epithelial thickness, seen in placentas of some smoking mothers. This increases the diffusion distance for oxygen and nutrients between mother and fetus, contributing to intrauterine growth restriction in infants of smoking mothers.

Treatable Traits in Pregnant Women with Asthma

BACKGROUND

Asthma is the most common chronic respiratory disease in pregnancy, affecting approximately 8-10% of pregnant women. Uncontrolled asthma is associated with adverse perinatal outcomes, including low birth weight, preterm birth, and maternal complications such as pre-eclampsia.

SUMMARY

A current approach to the management of chronic airway diseases is based on targeting treatable traits. The aim of this review was to define treatable traits in pregnant women with asthma based on recent literature and to determine personalized treatment options according to these traits. Traits addressed in this review that may improve asthma control and pregnancy outcomes are fractional exhaled nitric oxide-based asthma monitoring and treatment, medication adherence and inhalation technique, impaired lung function, smoking cessation and comorbidity including psychological conditions (depression and anxiety), obesity, rhinitis, gastroesophageal reflux disease, chronic rhinosinusitis with or without nasal polyps, and sleep apnea.

KEY MESSAGES

All the treatable traits discussed have the potential to improve asthma control and pregnancy outcomes in pregnant women with asthma. Further research is needed to determine which management approaches are best to improve asthma control during pregnancy, to identify other relevant treatable traits, and to determine whether the treatable trait approach is feasible and beneficial in pregnant women with asthma.

Preclinical Models of Attention Deficit Hyperactivity Disorder: Neurobiology, Drug Discovery, and Beyond

OBJECTIVE

We offer an overview of ADHD research using mouse models of nicotine exposure.

METHOD

Nicotine exposure of C57BL/6 or Swiss Webster mice occurred during prenatal period only or during the prenatal and the pre-weaning periods. Behavioral, neuroanatomical and neurotransmitter assays were used to investigate neurobiological mechanisms of ADHD and discover candidate ADHD medications.

RESULTS

Our studies show that norbinaltorphimine, a selective kappa opioid receptor antagonist is a candidate novel non-stimulant ADHD treatment and that a combination of methylphenidate and naltrexone has abuse deterrent potential with therapeutic benefits for ADHD. Other studies showed transgenerational transmission of ADHD-associated behavioral traits and demonstrated that interactions between untreated ADHD and repeated mild traumatic brain injury produced behavioral traits not associated with either condition alone.

CONCLUSION

Preclinical models contribute to novel insights into ADHD neurobiology and are valuable tools for drug discovery and translation to benefit humans with ADHD.

Exploring the prevalence, knowledge, attitudes and influencing factors of e-cigarette use among university students in Palestine: a cross-sectional study

OBJECTIVES

E-cigarettes have gained popularity, especially among young adults. This study aims to determine the prevalence of e-cigarette smoking, assess knowledge and attitudes and identify associated factors among Palestinian university students.

DESIGN

A cross-sectional study.

SETTING AND PARTICIPANTS

The study was conducted among Palestinian university students in early 2023.A self-administered questionnaire was used to survey 1792 students from six Palestine universities in the West Bank. The questionnaire covered various aspects, including sociodemographic information, daily habits, exposure to smoking, attitudes and knowledge about e-cigarettes. Data were analysed using descriptive statistics, χ2 tests and multivariate regression analysis.

RESULTS

The study revealed a high prevalence of tobacco use (41.2%), with e-cigarette use prevalent among 19.7% of participants. Knowledge about e-cigarettes was suboptimal, with misconceptions regarding their safety and health effects. Negative attitudes towards e-cigarettes were common, and students with negative attitudes were more likely to use e-cigarettes (aOR=2.6, 95% CI: 1.9 to 3.6). Gender (aOR=2.1, 95% CI: 1.4 to 3.0), waterpipe smoking (aOR=4.5, 95% CI: 3.2 to 6.3), physical inactivity (aOR=1.4, 95% CI: 1.1 to 1.9), high coffee consumption (aOR=1.6, 95% CI: 1.1 to 2.3), spending time with friends (aOR=2.4, 95% CI: 1.5 to 3.7), having a mother who is a smoker (aOR=1.5, 95% CI: 1.1 to 2.2) and having a friend who uses e-cigarettes (aOR=1.5, 95% CI: 1.1 to 2.1) were significantly associated with e-cigarettes use.

CONCLUSIONS

E-cigarette use is a growing concern among Palestinian university students. Combating this trend should include educational initiatives, social interventions and policy measures to promote informed decision-making and discourage e-cigarette use. Comprehensive tobacco control programs considering various tobacco and nicotine products and involving multiple stakeholders are warranted.

Maternal Tobacco Use During Pregnancy and Child Neurocognitive Development

Importance

Maternal tobacco use during pregnancy (MTDP) persists across the globe. Longitudinal assessment of the association of MTDP with neurocognitive development of offspring at late childhood is limited.

Objectives

To examine whether MTDP is associated with child neurocognitive development at ages 9 to 12 years.

Design, Setting, and Participants

This cohort study included children aged 9 and 10 years at wave 1 (October 2016 to October 2018) and aged 11 to 12 years at a 2-year follow-up (wave 2, August 2018 to January 2021) across 21 US sites in the Adolescent Brain Cognitive Development (ABCD) Study. Data were analyzed from June 2022 to December 2023.

Exposure

MTDP.

Main Outcomes and Measures

Outcomes of interest were neurocognition, measured by the National Institutes of Health (NIH) Toolbox Cognition Battery, and morphometric brain measures through the region of interest (ROI) analysis from structural magnetic resonance imaging (sMRI).

Results

Among 11 448 children at wave 1 (mean [SD] age, 9.9 [0.6] years; 5990 [52.3%] male), 1607 children were identified with MTDP. In the NIH Toolbox Cognition Battery, children with MTDP (vs no MTDP) exhibited lower scores on the oral reading recognition (mean [SE] B = -1.2 [0.2]; P < .001), picture sequence memory (mean [SE] B = -2.3 [0.6]; P < .001), and picture vocabulary (mean [SE] B = -1.2 [0.3]; P < .001) tests and the crystallized cognition composite score (mean [SE] B = -1.3 [0.3]; P < .001) at wave 1. These differential patterns persisted at wave 2. In sMRI, children with MTDP (vs no MTDP) had smaller cortical areas in precentral (mean [SE] B = -104.2 [30.4] mm2; P = .001), inferior parietal (mean [SE] B = -153.9 [43.4] mm2; P < .001), and entorhinal (mean [SE] B = -25.1 [5.8] mm2; P < .001) regions and lower cortical volumes in precentral (mean [SE] B = -474.4 [98.2] mm3; P < .001), inferior parietal (mean [SE] B = -523.7 [136.7] mm3; P < .001), entorhinal (mean [SE] B = -94.1 [24.5] mm3; P < .001), and parahippocampal (mean [SE] B = -82.6 [18.7] mm3; P < .001) regions at wave 1. Distinct cortical volume patterns continued to be significant at wave 2. Frontal, parietal, and temporal lobes exhibited differential ROI, while there were no notable distinctions in the occipital lobe and insula cortex.

Conclusions and Relevance

In this cohort study, MTDP was associated with enduring deficits in childhood neurocognition. Continued research on the association of MTDP with cognitive performance and brain structure related to language processing skills and episodic memory is needed.

Why and how should children be protected from the deluge of vaping related media and marketing overexposure?

E-cigarettes are products delivering nicotine via inhalation and are devised to mimic tobacco smoking. While they were initially introduced as a device putatively to aid with smoking cessation, their use is now far broader than that. Use by children is significantly increasing. There is growing evidence of the potential harms of vaping. E-liquids used for e-cigarettes contain a wide range of harmful substances, and the clinical consequences of this are now being increasingly demonstrated, such as the rise in cases of e-cigarette- or vaping-associated lung injury. In addition, early use may result in long-term nicotine addiction. Vaping companies utilise marketing methods that distinctly target young people, and weak legislation in the UK allows them free rein to expose children to vaping. In this review we demonstrate why children must be protected from vaping. We must have stringent legislation to prevent easy access to e-cigarettes, including banning the convenience and affordability disposable vapes provide, and prevent marketing that does not warn about the potential health effects. The Australia approach of prescription or pharmacy only access for smoking cessation should be considered to limit exposure of children and minimise use by nonsmokers.

[Pregnant women's use of tobacco and electronic cigarettes: A cross sectional survey]

OBJECTIVES

The article aims to describe tobacco and e-cigarette use among pregnant women: estimate the prevalence, identify the determinants and motivations of these behaviours.

METHODS

Cross-sectional, multicentre, descriptive observational study using self-administered questionnaires for pregnant women who visited ELENA healthcare centers in May 2021.

RESULTS

Of 223 patients, 38% were smokers before pregnancy and 16% continued to smoke during pregnancy. Nearly all the smokers (98%) declared that they had reduced or stopped their tobacco use, mostly without help. Young age, lack of professional activity, an unfavourable reaction to the announcement of the pregnancy, heavy smoking before the pregnancy and the presence of a smoker spouse were associated with smoking during pregnancy. Our study identified 10% of vapers before pregnancy and 7.2% during pregnancy. Of those who vaped during pregnancy, 81% were smokers before pregnancy. Most of them used a nicotine containing liquid and 38% of vapers combined smoking and e-cigarettes during pregnancy. There was no association between vaping during pregnancy and smoking cessation. A minority of women had received information about smoking during pregnancy.

CONCLUSIONS

The use of electronic cigarettes by pregnant women is a poorly-known reality in France, yet it concerns approximately 7% of the women in our sample. Prospective studies on larger numbers are needed to assess the prevalence of vaping among French pregnant women and its evolution during pregnancy.

Intrauterine exposure to nicotine through maternal vaping disrupts embryonic lung and skeletal development via the Kcnj2 potassium channel

Smoking cigarettes during pregnancy is associated with adverse effects on infants including low birth weight, defective lung development, and skeletal abnormalities. Pregnant women are increasingly turning to vaping [use of electronic (e)-cigarettes] as a perceived safer alternative to cigarettes. However, nicotine disrupts fetal development, suggesting that like cigarette smoking, nicotine vaping may be detrimental to the fetus. To test the impact of maternal vaping on fetal lung and skeletal development in mice, pregnant dams were exposed to e-cigarette vapor throughout gestation. At embryonic day (E)18.5, vape exposed litter sizes were reduced, and some embryos exhibited growth restriction compared to air exposed controls. Fetal lungs were collected for histology and whole transcriptome sequencing. Maternally nicotine vaped embryos exhibited histological and transcriptional changes consistent with impaired distal lung development. Embryonic lung gene expression changes mimicked transcriptional changes observed in adult mouse lungs exposed to cigarette smoke, suggesting that the developmental defects may be due to direct nicotine exposure. Fetal skeletons were analyzed for craniofacial and long bone lengths. Nicotine directly binds and inhibits the Kcnj2 potassium channel which is important for bone development. The length of the maxilla, palatal shelves, humerus, and femur were reduced in vaped embryos, which was further exacerbated by loss of one copy of the Kcnj2 gene. Nicotine vapor exposed Kcnj2KO/+ embryos also had significantly lower birth weights than unexposed animals of either genotype. Kcnj2 mutants had severely defective lungs with and without vape exposure, suggesting that potassium channels may be broadly involved in mediating the detrimental developmental effects of nicotine vaping. These data indicate that intrauterine nicotine exposure disrupts fetal lung and skeletal development likely through inhibition of Kcnj2.

Impact of in-utero electronic cigarette exposure on neonatal neuroinflammation, oxidative stress and mitochondrial function

Introduction: Despite the prevalence of the perception that electronic cigarettes (e-cig) are a safer alternative to tobacco smoke, growing concern about their potential toxic impact warrants adequate investigation focusing on special populations like maternal and pediatric groups. This study evaluated the consequences of maternal e-cig use on neonatal neuroinflammation, oxidative stress, and mitochondrial function in primary cultured neurons and postnatal day (PD) 7 and 90 brain. Methodology: Pregnant CD1 mice were exposed to e-cig vapor (2.4% nicotine) from gestational day 5 (E5) till PD7, and the primary neurons were isolated from pups at E16/17. Cellular total reactive oxygen species (ROS) and mitochondrial superoxide were measured in primary neurons using CM-H2DCFDA and Mitosox red, respectively. Mitochondrial function was assessed by Seahorse XF Cell Mitostress analysis. The level of pro-inflammatory cytokines was measured in primary neurons and PD7 and PD90 brains by RT-PCR and immunobead assay. Western blot analysis evaluated the expression of antioxidative markers (SOD-2, HO-1, NRF2, NQO1) and that of the proinflammatory modulator NF-κB. Results: Significantly higher level of total cellular ROS (p < 0.05) and mitochondrial superoxide (p < 0.01) was observed in prenatally e-cig-exposed primary neurons. We also observed significantly reduced antioxidative marker expression and increased proinflammatory modulator and cytokines expression in primary neurons and PD7 (p < 0.05) but not in PD90 postnatal brain. Conclusion: Our findings suggest that prenatal e-cig exposure induces postnatal neuroinflammation by promoting oxidative stress (OS), increasing cytokines' levels, and disrupting mitochondrial function. These damaging events can alter the fetal brain's immune functions, making such offspring more vulnerable to brain insults.

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.

Electronic Cigarette Use during Pregnancy: Is It Harmful?

Although combustible cigarette smoking rates have declined in recent years, alternative tobacco product use, particularly electronic cigarette use ("vaping"), has increased among young adults. Recent studies indicate that vaping during pregnancy is on the rise, possibly due to the perception that it is a safer alternative to combustible cigarette smoking. However, e-cigarette aerosols may contain several newer, potentially toxic compounds, including some known developmental toxicants that may adversely impact both the mother and the fetus. However, there is paucity of studies that have examined the effects of vaping during pregnancy. While the adverse perinatal outcomes of cigarette smoking during pregnancy are well established, the specific risks associated with inhaling vaping aerosols during pregnancy requires more research. In this article, we discuss the existing evidence and knowledge gaps on the risks of vaping during pregnancy. Studies that investigate vaping-associated systemic exposure and its effects (i.e., biomarker analyses) and maternal and neonatal clinical health outcomes are needed to reach more robust conclusions. We particularly emphasize the need to go beyond comparative studies with cigarettes, and advocate for research that objectively evaluates the safety of e-cigarettes and other alternative tobacco products.

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.

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.

Nicotine on the developing brain

Developmental periods such as gestation and adolescence have enhanced plasticity leaving the brain vulnerable to harmful effects from nicotine use. Proper brain maturation and circuit organization is critical for normal physiological and behavioral outcomes. Although cigarette smoking has declined in popularity, noncombustible nicotine products are readily used. The misperceived safety of these alternatives lead to widespread use among vulnerable populations such as pregnant women and adolescents. Nicotine exposure during these sensitive developmental windows is detrimental to cardiorespiratory function, learning and memory, executive function, and reward related circuitry. In this review, we will discuss clinical and preclinical evidence of the adverse alterations in the brain and behavior following nicotine exposure. Time-dependent nicotine-induced changes in reward related brain regions and drug reward behaviors will be discussed and highlight unique sensitivities within a developmental period. We will also review long lasting effects of developmental exposure persisting into adulthood, along with permanent epigenetic changes in the genome which can be passed to future generations. Taken together, it is critical to evaluate the consequences of nicotine exposure during these vulnerable developmental windows due to its direct impact on cognition, potential trajectories for other substance use, and implicated mechanisms for the neurobiology of substance use disorders.

Comparative study of e-cigarette aerosol and cigarette smoke effect on ex vivo embryonic chick lung explants

Electronic cigarette usage has significantly expanded among young people and pregnant women in the last decade. Although there are already some data regarding the short- and long-term consequences of e-cigarettes on human health, their effect on embryo and lung development still needs to be fully disclosed. In this sense, this study describes, for the first time, the impact of electronic cigarette aerosol on early lung development. For this purpose, ex vivo chick (Gallus gallus) embryonic lungs were cultured in vitro for 48 h in e-cigarette aerosol exposed-medium or unexposed medium. Chick lung explants were also cultured in a cigarette smoke-exposed medium for comparison purposes. Lung explants were morphologically analyzed to assess the impact on lung growth. Additionally, TNF-α levels were determined in the supernatant as a marker of pro-inflammatory response. The results suggest that electronic cigarette aerosol impairs lung growth and promotes lung inflammation. However, its impact on early lung growth seems less detrimental than conventional cigarette smoke. This work provides significant data regarding the impact of e-cig aerosol, adding to the efforts to fully understand its effect on embryo development. The validation of these effects may eventually lead to new tobacco control recommendations for pregnant women.

Sex-Specific Alterations of the Lung Transcriptome at Birth in Mouse Offspring Prenatally Exposed to Vanilla-Flavored E-Cigarette Aerosols and Enhanced Susceptibility to Asthma

Currently, approximately 8 million adult Americans use electronic cigarettes (e-cigs) daily, including women of childbearing age. It is known that more than 10% of women smoke during their pregnancy, and recent surveys show that rates of maternal vaping are similar to rates of maternal cigarette smoking. However, the effects of inhaling e-cig aerosol on the health of fetuses remain unknown. The objective of the present study was to increase our understanding of the molecular effects caused by in utero exposures to e-cig aerosols on developing mouse lungs and, later in life, on the offspring's susceptibility to developing asthma.

METHODS

Pregnant mice were exposed throughout gestation to either filtered air or vanilla-flavored e-cig aerosols containing 18 mg/mL of nicotine. Male and female exposed mouse offspring were sacrificed at birth, and then the lung transcriptome was evaluated. Additionally, once sub-groups of male offspring mice reached 4 weeks of age, they were challenged with house dust mites (HDMs) for 3 weeks to assess asthmatic responses.

RESULTS

The lung transcriptomic responses of the mouse offspring at birth showed that in utero vanilla-flavored e-cig aerosol exposure significantly regulated 88 genes in males (62 genes were up-regulated and 26 genes were down-regulated), and 65 genes were significantly regulated in females (17 genes were up-regulated and 48 genes were down-regulated). Gene network analyses revealed that in utero e-cig aerosol exposure affected canonical pathways associated with CD28 signaling in T helper cells, the role of NFAT in the regulation of immune responses, and phospholipase C signaling in males, whereas the dysregulated genes in the female offspring were associated with NRF2-mediated oxidative stress responses. Moreover, we found that in utero exposures to vanilla-flavored e-cig aerosol exacerbated HDM-induced asthma in 7-week-old male mouse offspring compared to respective in utero air + HDM controls.

CONCLUSIONS

Overall, these data demonstrate that in utero e-cig aerosol exposure alters the developing mouse lung transcriptome at birth in a sex-specific manner and provide evidence that the inhalation of e-cig aerosols is detrimental to the respiratory health of offspring by increasing the offspring' susceptibility to developing lung diseases later in life.

Birth Outcomes Associated With E-Cigarette and Non-E-Cigarette Tobacco Product Use During Pregnancy: An Examination of PATH Data Waves 1-5

OBJECTIVES

To examine associations of prenatal e-cigarette use to pregnancy and birth outcomes.

METHODS

Currently pregnant women (n = 1 037) from Waves 1 through 4 of the Population Assessment of Tobacco and Health Study who had pregnancy or live birth outcome data in a subsequent wave (Waves 2-5; 2013 to 2019). Weighted bivariate and multivariable models\ examined associations between past 30-day tobacco use assessed during pregnancy (any past 30-day e-cigarette use, any past 30-day non-e-cigarette tobacco use, or no past 30-day tobacco use) with adverse pregnancy (miscarriage, abortion, ectopic or tubal pregnancy, stillbirth) and birth outcomes (preterm birth, low birth weight, birth defect, placenta previa, placental abruption, pre-eclampsia) reported in the subsequent wave.

RESULTS

Approximately 1% of pregnant women reported past 30-day exclusive e-cigarette use and 3.2% used e-cigarettes and one other tobacco product. Compared to no tobacco use, past 30-day e-cigarette use (exclusive or use with another tobacco product) during pregnancy was not associated with increased odds of an adverse pregnancy or birth outcome in bivariate or multivariable models. Past 30-day non-e-cigarette tobacco use was associated with increased odds of an adverse pregnancy outcome in multivariable models, but not an adverse live birth outcome. Compared to past 30-day cigarette use, past 30-day e-cigarette use during pregnancy was not associated with lowered odds of a birth or pregnancy outcome.

CONCLUSIONS

E-cigarette use during pregnancy is rare. Understanding the positive and negative impacts of pre-natal e-cigarette use on women's health may guide public health messaging campaigns.

IMPLICATIONS

Results showed that past 30-day e-cigarette use during pregnancy was low, with cigarette smoking remaining the most prevalent form of tobacco use during pregnancy. Current e-cigarette use during pregnancy used either exclusively or with another tobacco product, was not associated with increased risk of an adverse pregnancy, or birth outcome. A small sample size of e-cigarette users and limited information on quantity and frequency of e-cigarette use before and during pregnancy may limit conclusions. Healthcare providers may use this information when discussing the harms and consequences associated with e-cigarette and tobacco use during pregnancy.

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

BACKGROUND

Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member.

METHODS

This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period.

RESULTS

Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old.

CONCLUSIONS

We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

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.

Impact of Prenatal Nicotine Exposure on Placental Function and Respiratory Neural Network Development

Smoking during pregnancy is associated with multiple undesirable outcomes in infants, such as low birth weight, increased neonatal morbidity and mortality, and catastrophic conditions like sudden infant death syndrome (SIDS). Nicotine, the most addictive and teratogenic substance in tobacco smoke, reaches and crosses the placenta and can be accumulated in the amniotic fluid and distributed by fetal circulation, altering the cholinergic transmission by acting on the nicotinic acetylcholine receptors (nAChRs) expressed from very early gestational stages in the placenta and fetal tissue. Because nAChRs influence the establishment of feto-maternal circulation and the emergence of neuronal networks, prenatal nicotine exposure can lead to multiple alterations in newborns. In this mini-review, we discuss the undeniable effects of nicotine in the placenta and the respiratory neural network as examples of how prenatal nicotine and smoking exposition can affect brain development because dysfunction in this network is involved in SIDS etiology.

E-cigarette use during pregnancy and its association with adverse birth outcomes in the US

The popularity of e-cigarette use among young adults is a growing concern. However, little is known about factors associated with e-cigarette use in pregnant women and birth outcomes. In this retrospective cohort study, we evaluated the influence of several factors on behavioral changes in e-cigarette use before and during pregnancy, and assessed the association between e-cigarette use and subsequent birth outcomes among pregnant women. The Population Assessment of Tobacco and Health (PATH) study, a government-sponsored national longitudinal study based in the US, Waves 1 through 4 (2013-2018) were used. Multivariate logistic regressions were conducted to estimate behavioral changes in e-cigarette use during pregnancy and subsequent influence on high-risk birth (e.g., preterm birth, low birth weight, birth defects, etc.) and fetal death. Although pregnant women who quit vaping before pregnancy (OR = 1.14, 95% CI 0.54-2.40) or had any use during pregnancy (OR = 1.19, 95% CI 0.38-3.73) showed non-differential risk of having a high-risk birth in comparison to women who did not initiate vaping, we observed that the usage of mint/menthol flavor was correlated with higher risk of fetus death (OR = 3.27, 95% CI 1.17-9.19). Healthcare providers should encourage e-cigarette users to quit prior to and during early pregnancy.

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.

Mapping of Global Research on Electronic Cigarettes: A Bibliometric Analysis

Electronic cigarettes (E-cigarettes) use has increased rapidly in the past decades and has been widely studied by scholars worldwide, whereas the research topics and development trends in this field are still unclear. This study aimed to explore the landscape of research relating to e-cigarettes. The data outputted from the Web of Science Core Collection database was used for bibliometric analysis. Frequencies and percentages were used to describe the publications' characteristics. Visualizing maps were designed using VOSviewer 1.6.9 and CiteSpace 5.8 R2. Overall, a total of 7,979 records were identified in the database and the number of researches increased rapidly since 2010. All publications involved 19837 authors, with the top ten authors contributing to 8.71% (695) of all documents. The most productive country and institution were the United States of America and the University of California San Francisco, respectively. Nicotine & Tobacco Research was not only the journal with the most published papers but also the most co-cited journal. The main research domains in this field were the prevalence, awareness, reasons for using e-cigarettes; e-cigarettes use for tobacco harm reduction; exposure in the population; and the relationship between e-cigarettes and tobacco and nicotine. E-cigarettes researches have become a popular field for scholars. The hot topics on e-cigarette research were extensive and changed over the past decade.

E-cigarettes and youth: an unresolved Public Health concern

The use of electronic cigarettes (e-cigarette) and vaping devices started as a potential aid for cessation and reducing the harmful consequences of cigarette smoking, mainly in the adult population. Today e-cigarette use is highly increasing in vulnerable populations, especially young and pregnant women, due to the misconception of its harmless use.

Despite the growing acknowledgment in e-cigarette as a potential harmful device, and due to mixed information found concerning its beneficial aid for smokers, along with an insufficient clinical study done in human models, it is important to further evaluate the possible benefits and risks of non-combusting, vaping nicotine or non-nicotine delivery devices.

In this review we tried to summarize the latest updated information found in the literature, concentrating mainly in the variety of adverse effects of e-cigarette use and its contribution for recent and future health concerns.

Pregnancy Outcomes Associated With Use of Tobacco and Marijuana

Tobacco and marijuana are the most common drugs of abuse among pregnant women. Cigarettes have been extensively studied and increase the risk of miscarriage, preterm birth, premature rupture of membranes, placental dysfunction, low birth rate, stillbirth, and infant mortality. There are sparse data on the specific effects of electronic cigarettes and smokeless tobacco in pregnancy. Literature on marijuana in pregnancy is limited by confounding, bias, and the retrospective nature of studies that do not capture contemporary trends in use. However, several studies suggest an association between marijuana and fetal growth restriction, low birth weight, and neurodevelopmental differences in offspring.

Electronic cigarettes versus nicotine patches for smoking cessation in pregnancy: a randomized controlled trial

Nicotine replacement therapy, in the form of nicotine patches, is commonly offered to pregnant women who smoke to help them to stop smoking, but this approach has limited efficacy in this population. Electronic cigarettes (e-cigarettes) are also used by pregnant women who smoke but their safety and efficacy in pregnancy are unknown. Here, we report the results of a randomized controlled trial in 1,140 participants comparing refillable e-cigarettes with nicotine patches. Pregnant women who smoked were randomized to e-cigarettes (n = 569) or nicotine patches (n = 571). In the unadjusted analysis of the primary outcome, validated prolonged quit rates at the end of pregnancy in the two study arms were not significantly different (6.8% versus 4.4% in the e-cigarette and patch arms, respectively; relative risk (RR) = 1.55, 95%CI: 0.95-2.53, P = 0.08). However, some participants in the nicotine patch group also used e-cigarettes during the study. In a pre-specified sensitivity analysis excluding abstinent participants who used non-allocated products, e-cigarettes were more effective than patches (6.8% versus 3.6%; RR = 1.93, 95%CI: 1.14-3.26, P = 0.02). Safety outcomes included adverse events and maternal and birth outcomes. The safety profile was found to be similar for both study products, however, low birthweight (<2,500 g) was less frequent in the e-cigarette arm (14.8% versus 9.6%; RR = 0.65, 95%CI: 0.47-0.90, P = 0.01). Other adverse events and birth outcomes were similar in the two study arms. E-cigarettes might help women who are pregnant to stop smoking, and their safety for use in pregnancy is similar to that of nicotine patches. ISRCTN62025374.

Patterns and Trends in Use of Electronic Nicotine Delivery Systems Before and During Pregnancy: Pregnancy Risk Assessment Monitoring System, United States, 2016-2019

INTRODUCTION

This study used 2016-2019 Pregnancy Risk Assessment Monitoring System data to estimate prevalence of electronic nicotine delivery system (ENDS) use around pregnancy, changes in ENDS use and cigarette smoking from before to during pregnancy, and trends in these behaviors over time.

METHODS

ENDS and cigarette use during the 3 months before and the last three months of pregnancy were measured. Weighted prevalence estimates and 95% confidence intervals were estimated for outcomes overall and ENDS use by maternal characteristic for 2016-2019; logistic regression tested for differences in ENDS use by maternal characteristic and for linear trends in ENDS and cigarette use before and during pregnancy. Analyses were completed in 2021.

RESULTS

In 2019, 4.3% (N = 98,050) of women used ENDS before and 1.3% (N = 28,811) used ENDS during pregnancy. Most exclusive ENDS users (82.2%) and exclusive cigarette smokers (55.0%) stopped use during pregnancy. Among dual users, 46.3% stopped use during pregnancy while 20.2% continued dual use and 24.9% smoked cigarettes exclusively. Few dual users (8.6%) and exclusive cigarette smokers (0.5%) reported using ENDS exclusively during pregnancy. From 2016-2019, exclusive ENDS use increased and exclusive cigarette smoking decreased both before and during pregnancy.

CONCLUSIONS

ENDS use during pregnancy is low but increased since 2016. Less than one-half of dual ENDS and cigarettes users quit during pregnancy; few dual users or exclusive cigarette smokers switched to exclusive ENDS use during pregnancy. Continued surveillance of ENDS and other tobacco use during pregnancy is critical to inform public health activities that protect maternal and child health.

Harmful Effect of Intrauterine Smoke Exposure on Neuronal Control of "Fetal Breathing System" in Stillbirths

This article is aimed to contribute to the current knowledge on the role of toxic substances such as nicotine on sudden intrauterine unexplained deaths’ (SIUDS’) pathogenetic mechanisms. The in-depth histopathological examination of the autonomic nervous system in wide groups of victims of SIUDS (47 cases) and controls (20 cases), with both smoking and no-smoking mothers, highlighted the frequent presence of the hypodevelopment of brainstem structures checking the vital functions. In particular, the hypoplasia of the pontine parafacial nucleus together with hypoplastic lungs for gestational age were observed in SIUDS cases with mothers who smoked cigarettes, including electronic ones. The results allow us to assume that the products of cigarette smoke during pregnancy can easily cross the placental barrier, thus entering the fetal circulation and damaging the most sensitive organs, such as lungs and brain. In a non-negligible percentage of SIUDS, the mothers did not smoke. Furthermore, based on previous and ongoing studies conducted through analytical procedures and the use of scanning electron microscopy, the authors envisage the involvement of toxic nanoparticles (such as agricultural pesticides and nanomaterials increasingly used in biomedicine, bioscience and biotechnology) in the death pathogenesis, with similar mechanisms to those of nicotine.

Biological determinants impact the neurovascular toxicity of nicotine and tobacco smoke: A pharmacokinetic and pharmacodynamics perspective

Accumulating evidence suggests that the detrimental effect of nicotine and tobacco smoke on the central nervous system (CNS) is caused by the neurotoxic role of nicotine on blood-brain barrier (BBB) permeability, nicotinic acetylcholine receptor expression, and the dopaminergic system. The ultimate consequence of these nicotine associated neurotoxicities can lead to cerebrovascular dysfunction, altered behavioral outcomes (hyperactivity and cognitive dysfunction) as well as future drug abuse and addiction. The severity of these detrimental effects can be associated with several biological determinants. Sex and age are two important biological determinants which can affect the pharmacokinetics and pharmacodynamics of several systemically available substances, including nicotine. With regard to sex, the availability of gonadal hormone is impacted by the pregnancy status and menstrual cycle resulting in altered metabolism rate of nicotine. Additionally, the observed lower smoking cessation rate in females compared to males is a consequence of differential effects of sex on pharmacokinetics and pharmacodynamics of nicotine. Similarly, age-dependent alterations in the pharmacokinetics and pharmacodynamics of nicotine have also been observed. One such example is related to severe vulnerability of adolescence towards addiction and long-term behavioral changes which may continue through adulthood. Considering the possible neurotoxic effects of nicotine on the central nervous system and the deterministic role of sex as well as age on these neurotoxic effects of smoking, it has become important to consider sex and age to study nicotine induced neurotoxicity and development of treatment strategies for combating possible harmful effects of nicotine. In the future, understanding the role of sex and age on the neurotoxic actions of nicotine can facilitate the individualization and optimization of treatment(s) to mitigate nicotine induced neurotoxicity as well as smoking cessation therapy. Unfortunately, however, no such comprehensive study is available which has considered both the sex- and age-dependent neurotoxicity of nicotine, as of today. Hence, the overreaching goal of this review article is to analyze and summarize the impact of sex and age on pharmacokinetics and pharmacodynamics of nicotine and possible neurotoxic consequences associated with nicotine in order to emphasize the importance of including these biological factors for such studies.

E-liquids and vanillin flavoring disrupts retinoic acid signaling and causes craniofacial defects in Xenopus embryos

Environmental teratogens such as smoking are known risk factors for developmental disorders such as cleft palate. While smoking rates have declined, a new type of smoking, called vaping is on the rise. Vaping is the use of e-cigarettes to vaporize and inhale an e-liquid containing nicotine and food-like flavors. There is the potential that, like smoking, vaping could also pose a danger to the developing human. Rather than waiting for epidemiological and mammalian studies, we have turned to an aquatic developmental model, Xenopus laevis, to more quickly assess whether e-liquids contain teratogens that could lead to craniofacial malformations. Xenopus, like zebrafish, has the benefit of being a well-established developmental model and has also been effective in predicting whether a chemical could be a teratogen. We have determined that embryonic exposure to dessert flavored e-liquids can cause craniofacial abnormalities, including an orofacial cleft in Xenopus. To better understand the underlying mechanisms contributing to these defects, transcriptomic analysis of the facial tissues of embryos exposed to a representative dessert flavored e-liquid vapor extract was performed. Analysis of differentially expressed genes in these embryos revealed several genes associated with retinoic acid metabolism or the signaling pathway. Consistently, retinoic acid receptor inhibition phenocopied the craniofacial defects as those embryos exposed to the vapor extract of the e-liquid. Such malformations also correlated with a group of common differentially expressed genes, two of which are associated with midface birth defects in humans. Further, e-liquid exposure sensitized embryos to forming craniofacial malformations when they already had depressed retinoic acid signaling. Moreover, 13-cis-retinoic acid treatment could significantly reduce the e-liquid induced malformation in the midface. Such results suggest the possibility of an interaction between retinoic acid signaling and e-liquid exposure. One of the most popular and concentrated flavoring chemicals in dessert flavored e-liquids is vanillin. Xenopus embryos exposed to this chemical closely resembled embryos exposed to dessert-like e-liquids and a retinoic acid receptor antagonist. In summary, we determined that e-liquid chemicals, in particular vanillin, can cause craniofacial defects potentially by dysregulating retinoic acid signaling. This work warrants the evaluation of vanillin and other such flavoring additives in e-liquids on mammalian development.

Nicotine replacement therapy and e-cigarettes in pregnancy and infant respiratory outcomes

BACKGROUND

Nicotine replacement therapy (NRT) and e-cigarettes are recommended to pregnant women who wish to stop smoking. Albeit eliminating other harmful components of cigarettes, those alternatives still expose the developing fetus to nicotine. The lungs may be particularly vulnerable to damage by nicotine as there is widespread nicotinic-acetylcholine receptor expression in the lungs. There is, however, a paucity of information about the effect of NRT and e-cigarette use in pregnancy on infant respiratory outcomes.

AIMS

To explore the effect of NRT and e-cigarettes on the developing lung.

STUDY DESIGN

A literature search was undertaken to examine the use and safety of nicotine-replacement strategies in pregnancy, with a focus on infant respiratory outcomes. This included experimental studies investigating the effect of isolated "gestational" nicotine on the developing lung.

OUTCOME MEASURES

Respiratory outcomes in animal studies and infants.

RESULTS

Animal studies investigating the effect of gestational nicotine exposure on fetal lung development demonstrated abnormal lung growth; including abnormal airway branching and alveolar development. Consequently, offspring display altered pulmonary mechanics, including both increased respiratory rate and airway resistance. These findings mirror respiratory pathology observed in infants born to smoking mothers. Human trials of NRT and e-cigarette use in pregnancy have not identified adverse perinatal outcomes regarding reduced birthweight or prematurity, but have not considered infant and childhood respiratory outcomes.

CONCLUSIONS

Nicotine can impair fetal lung development, leading to concerns regarding the safety of NRT and e-cigarettes in pregnancy. Studies have yet to explore the impact of these nicotine-containing products on infant respiratory outcomes.

Third Trimester Lower Extremity Lymphorrhea

Introduction

Lower extremity edema is one of the most common complaints among pregnant patients. However, there is no literature mentioning weeping edema (i.e., lymphorrhea) in a pregnant woman who has no concordant underlying renal and/or cardiac pathology. There is also a lack of evidence and recommendations regarding the therapeutic benefit and safety profile of diuretic use to treat profound pregnancy-associated edema. Herein, we present the case of 32-year-old female who presented with a significant lymphorrhea during the third trimester without cardiac or renal comorbidity and was successfully treated with torsemide. Case Report. We report a case of a 32-year-old multigravida patient pregnant with her third child and has two living full-term children (G3P2003). Her pregnancy was complicated by obesity, smoking (vape), and previous history of fetal growth restriction. The patient presented for routine prenatal care at 9-week gestation. She was diagnosed with chronic hypertension at 19 weeks of pregnancy based upon systolic blood pressure > 140. Lifestyle modifications were recommended, but the patient did not comply. At her 31-week office visit, the patient presented with anasarca and clear, slightly viscous fluid seeping through the atraumatic skin of her lower extremities. Preeclampsia, renal, cardiac, vascular, and infectious complications were all ruled out. The patient responded positively to loop diuretic therapy. Torsemide was found to be far more beneficial than furosemide. The patient was induced at 37 weeks secondary to chronic hypertension requiring antihypertensive therapy. Delivery was uncomplicated. The patient gave birth to a healthy male with birth weight of 2,920 g via spontaneous vaginal delivery. Discussion. Pitting edema of lower limbs frequently occurs as a result of fluid overload and chronic venous insufficiency, and pregnancy is one of the known risk factors. Additionally, the blockage of lymphatic channel with the gravida uterus likely was the main contributing factor for her lymphorrhea. In this patient, the capillary hydrostatic pressure was likely accentuated due to hypertension, obesity, and vaping. Furosemide was minimally effective to alleviate her symptoms. Torsemide provided much more effective diuresis and symptom control. However, her symptoms persisted until delivery.

Conclusion

Torsemide provided significant therapeutic benefit over furosemide in this patient without adverse maternal, fetal, or neonatal outcomes. Further study is needed to assess the safe use of loop diuretics in the pregnant population who suffers from significant lower extremity edema.

Smoking and vaping patterns during pregnancy and the postpartum: A longitudinal UK cohort survey

INTRODUCTION

There is limited information about longitudinal patterns of vaping during pregnancy and the postpartum. We describe the prevalence, frequency, and reasons for vaping throughout pregnancy and postpartum. We also describe temporal patterns in pregnant women's vaping.

METHODS

A longitudinal cohort study across England and Scotland, with questionnaires in early pregnancy (8-24 weeks gestation), late pregnancy (34-38 weeks) and 3 months postpartum. A total of 750 women, aged 16 years or over, who were either current smokers, vapers or had smoked in the 3 months before pregnancy, were recruited between June and November 2017.

RESULTS

Vaping prevalence was 15.9% (n = 119/750) in early pregnancy: 12.4% (n = 93/750) were dual users and 3.5% (n = 26/750) exclusive vapers. Late pregnancy vaping prevalence was 17.8% (n = 68/383): 12.5% (n = 48/383) were dual users and 5.2% (n = 20/383) exclusive vapers. Postpartum vaping prevalence was 23.1% (n = 95/411): 14.6% (n = 60/411) were dual users and 8.5% (n = 35/411) exclusive vapers. The most frequently reported reason to vape among all vapers was to quit smoking. A total of 316 women completed all three surveys: 2.6% (n = 8/316) were exclusive vapers in early pregnancy with most remaining exclusive vapers postpartum (n = 6/8, 75%). Of the 11.5% (n = 35/316) dual users in early pregnancy, 31.4% (n = 11/35) were exclusive smokers by the postpartum.

CONCLUSION

Vaping prevalence was between 15.9% and 23.1% during pregnancy and the postpartum period, and the majority were dual users. Vaping habits of exclusive vapers remains stable throughout pregnancy and the postpartum. However, the vaping habits of dual users varies, with a third exclusively smoking in the postpartum.

ICP-MS Determination of 23 Elements of Potential Health Concern in Liquids of e-Cigarettes. Method Development, Validation, and Application to 37 Real Samples

The lack of interest in the determination of toxic elements in liquids for electronic cigarettes (e-liquids) has so far been reflected in the scarce number of accurate and validated analytical methods devoted to this aim. Since the strong matrix effects observed for e-liquids constitute an exciting analytical challenge, the main goal of this study was to develop and validate an ICP-MS method aimed to quantify 23 elements in 37 e-liquids of different flavors. Great attention has been paid to the critical phases of sample pre-treatment, as well as to the optimization of the ICP-MS conditions for each element and of the quantification. All samples exhibited a very low amount of the elements under investigation. Indeed, the sum of their average concentration was of ca. 0.6 mg kg-1. Toxic elements were always below a few tens of a μg per kg-1 and, very often, their amount was below the relevant quantification limits. Tobacco and tonic flavors showed the highest and the lowest concentration of elements, respectively. The most abundant elements came frequently from propylene glycol and vegetal glycerin, as confirmed by PCA. A proper choice of these substances could further decrease the elemental concentration in e-liquids, which are probably barely involved as potential sources of toxic elements inhaled by vapers.

Effect of E-cigarettes aerosol exposure during lactation in rats: Hormonal and biochemical aspects

Electronic cigarettes (e-cigarettes) have been marketed as a less lethal substitute for smoking traditional cigarettes. This study aims to investigate the impact of e-cigarettes aerosol exposure on lactating dams and pups, whose dams were exposed. Lactating dams received fresh air (control) or e-cigarettes aerosol during lactation (day 4-21). Maternal exposure to e-cigarettes aerosol during lactation induced significant reduction (P < 0.0001) in the fat content of the milk and serum Leptin level (P < 0.005) compared to control dams. Furthermore, pups whose dams were exposed to e-cigarettes during lactation showed an increased level of glucose, thyroxine and decreased level of insulin. The exposure to e-cigarettes aerosol during lactation altered the composition of milk as well as the hormonal and biochemical profile in dams and pups. This result, if observed in women using e-cigarettes, suggests that e-cigarettes' use during lactation may have consequences on the milk production and hormonal and biochemical profile in breastfeeding mothers and nursing babies.

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.

Regional comparison of self-reported late pregnancy cigarette smoking to mass spectrometry analysis

OBJECTIVE

To report a more accurate prevalence estimate of late pregnancy nicotine exposures.

STUDY DESIGN

A cross-sectional study during a 2-month period in 2019. Participants were women delivering in any of the six county maternity hospitals who consented to universal drug testing at the time of delivery as part of routine hospital admission.

RESULTS

Of 2531 tested samples, 18.7% tested positive for high levels of cotinine indicating primary smoking or other primary use of tobacco products. Together, 33.0% of the study population tested positive for nicotine exposure during late pregnancy compared to vital records which reported 8.2% cigarette smoking during the third trimester of pregnancy and 10.5% cigarette smoking at any time during pregnancy through maternal self-report.

CONCLUSION

Captured vital birth smoking measures vastly underreport actual primary exposures to nicotine products. Vital birth data also fail to capture secondhand exposures which constitute a significant proportion of the population.

DNA methylome perturbations: an epigenetic basis for the emergingly heritable neurodevelopmental abnormalities associated with maternal smoking and maternal nicotine exposure†

Maternal smoking during pregnancy is associated with an ensemble of neurodevelopmental consequences in children and therefore constitutes a pressing public health concern. Adding to this burden, contemporary epidemiological and especially animal model research suggests that grandmaternal smoking is similarly associated with neurodevelopmental abnormalities in grandchildren, indicative of intergenerational transmission of the neurodevelopmental impacts of maternal smoking. Probing the mechanistic bases of neurodevelopmental anomalies in the children of maternal smokers and the intergenerational transmission thereof, emerging research intimates that epigenetic changes, namely DNA methylome perturbations, are key factors. Altogether, these findings warrant future research to fully elucidate the etiology of neurodevelopmental impairments in the children and grandchildren of maternal smokers and underscore the clear potential thereof to benefit public health by informing the development and implementation of preventative measures, prophylactics, and treatments. To this end, the present review aims to encapsulate the burgeoning evidence linking maternal smoking to intergenerational epigenetic inheritance of neurodevelopmental abnormalities, to identify the strengths and weaknesses thereof, and to highlight areas of emphasis for future human and animal model research therein.

Electronic Nicotine Delivery Systems (ENDS) Use and Pregnancy I: ENDS Use Behavior During Pregnancy

PURPOSE OF REVIEW

This review examines Electronic Nicotine Delivery Systems (ENDS) use behavior during pregnancy, including the prevalence of and transitions in use during pregnancy.

RECENT FINDINGS

Twenty-two papers addressed the prevalence of and/or transitions in ENDS use during pregnancy. Findings show a complex landscape of ENDS use. A minority (0.4%-7.0%) of pregnant persons use ENDS; most commonly this occurs in the form of dual use (ENDS and combustible cigarettes (CC); 75%). Many pregnant persons report using ENDS because they perceive them to be a lower-risk alternative and/or potential cessation aide for CC smoking. However, while a subset of those who use ENDS do quit all tobacco product use during pregnancy, only a small proportion switch from exclusive CC smoking to exclusive ENDS use.

SUMMARY

ENDS are a somewhat new addition to the tobacco product landscape. The perception of ENDS as a lower-risk alternative may contribute to ENDS use in pregnancy. There is insufficient evidence to support the notion that ENDS facilities the cessation of tobacco product use during pregnancy.

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.

Factors Associated With Cannabis Use During the Reproductive Cycle: A Retrospective Cross-Sectional Study of Women in States With Recreational and Medical Cannabis Legalization

INTRODUCTION

Passage of cannabis laws may impact cannabis use and the use of other substances. The suggested association is of particular concern in pregnant women where exposure to substances can cause harm to both the pregnant woman and fetus. The present study contributes to the minimal literature on factors associated with cannabis use during the preconception, prenatal, and postpartum periods including state legalization status, concurrent use of tobacco and e-cigarettes and adequacy of prenatal care.

METHODS

We conducted a cross-sectional analysis using combined survey data from the 2016-2018 Pregnancy Risk Assessment Monitoring System (PRAMS) collected from 36,391 women. Logistic regression was used to estimate the impact of state-legalization, adequacy of prenatal care, and other substance use on cannabis use during the preconception, prenatal, and post-partum periods.

RESULTS

In the preconception model, residence in a recreationally legal state (OR: 2.37; 95% CI, 2.04-2.75) or medically legal state (OR:3.32; 95% CI, 2.90-3.80) compared to a non-legal state was associated with higher odds of cannabis use. In the prenatal model, residence in a recreationally legal state was associated with higher odds of cannabis use (OR: 1.51; 95% CI, 1.29-1.79) whereas there was no association with residence in a medically legal state. Tobacco use including e-cigarettes and moderate prenatal alcohol use were also significantly associated with cannabis use.

CONCLUSION

Recreational cannabis legalization is associated with the use of cannabis prior to, during, and after pregnancy. Renewed clinical and policy efforts may be warranted to update prenatal substance use prevention programs, educational campaigns, and provider education as cannabis legalization evolves.

Prenatal nicotine exposure was associated with long-term impact on the cardiovascular system and regulation-Review

AIM

The aim of this structured review was to discuss knowledge of nicotine use during pregnancy and long-term effects on children's cardiovascular function.

METHODS

PubMed and MEDLINE were searched for original papers that covered various forms of nicotine exposure during pregnancy and this identified 314 papers published in English from inception of the databases to 1 March 2021. The research focus was prenatal exposure that had long-term effects on the cardiovascular system. The search was expanded from the reference list of the selected papers, which identified another 17 papers.

RESULTS

The 34 original papers that were included covered 172,696 subjects from foetuses to 19 years of age. Cardiovascular autonomic dysfunction was discussed in 12 of the papers and 16 studies reported on blood pressure. The remaining studies covered structural or functional changes in arterial wall or heart. There were convincing data on autonomic dysfunction and increased blood pressure. Some data were conflicting and problems with misclassification of exposure were evident.

CONCLUSION

Prenatal nicotine exposure was associated with long-term developmental changes in the cardiovascular system and regulation. There were no safe periods, doses or nicotine products during pregnancy and women should abstain when planning a pregnancy.