In utero exposures to mint-flavored JUUL aerosol impair lung development and aggravate house dust mite-induced asthma in adult offspring mice

Perinatal nicotine vaping exposure induces pro-myofibroblastic phenotype in rat bone marrow-derived mesenchymal stem cells

Perinatal nicotine exposure via tobacco smoking results in increased proclivity to chronic lung disease (CLD); however, the underlying molecular mechanisms remain incompletely understood. We previously demonstrated that in addition to nicotine's direct effects on the developing lung, there are also adverse molecular alterations in bone marrow-derived mesenchymal stem cells (BMSCs), which are vital to lung injury repair. Whether perinatal nicotine exposure via electronic-cigarette (e-cig) vaping also adversely affects BMSCs is unknown. This is highly relevant due to marked increase in e-cig vaping including by pregnant women. Hypothesizing that perinatal nicotine exposure via e-cig vaping predisposes BMSCs to a pro-myofibroblastic phenotype, pregnant rat dams were exposed to fresh air (control), vehicle (e-cig without nicotine), or e-cig (e-cig with nicotine) daily during pregnancy and lactation. At postnatal day 21, offspring BMSCs were isolated and studied for cell proliferation, migration, wound healing response, and expression of key Wnt and PPARγ signaling intermediates (β-catenin, LEF-1, PPARγ, ADRP and C/EBPα) and myogenic markers (fibronectin, αSMA, calponin) proteins using immunoblotting. Compared to controls, perinatal e-cig exposure resulted in significant decrease in BMSC proliferation, migration, and wound healing response. The expression of key Wnt signaling intermediates (β-catenin, LEF-1) and myogenic markers (fibronectin, αSMA, calponin) increased significantly, while PPARγ signaling intermediates (PPARγ, ADRP, and C/EBPα) decreased significantly. Based on these data, we conclude that perinatally e-cig exposed BMSCs demonstrate pro-myofibroblastic phenotype and impaired injury-repair potential, indicating a potentially similar susceptibility to CLD following perinatal nicotine exposure via vaping as seen following parenteral perinatal nicotine exposure.

Maternal use of electronic cigarettes and impact on offspring: a double-hit model

Endothelial dysfunction is a predictor for cardiovascular disease. Preclinical data suggest longstanding cardiovascular and cerebrovascular dysfunction occurs in offspring with perinatal electronic cigarette (Ecig) exposure. Furthermore, direct use of Ecigs increases reactive oxygen species and impairs cerebrovascular function, but the combined effect of direct use in offspring with a history of perinatal exposure (i.e. double-hit condition) is not known. We tested the hypothesis that offspring with double-hit Ecig exposure will lead to greater cerebrovascular and neurocognitive dysfunction compared with in utero exposure only. Male and female offspring were obtained from time-mated Sprague Dawley female rats exposed to air (n = 5 dams) or Ecig exposed (n = 5 dams) and studied at either 3 or 6 mo after birth. Ecig exposure for double-hit offspring began at 1-mo before the timepoints and lasted 4 wk (5 days/wk with 90-min exposure/day). We found double-hit offspring (Ecig:Ecig = exposure dam:offspring) sustained further blunted middle cerebral artery (MCA) reactivity, increased severity of neuronal damage, and increased interactions of astrocytes and endothelial cells compared with offspring with maternal (Ecig:Air) or direct (Air:Ecig) exposure only. Circulating extracellular vesicles (EVs) were increased, whereas sirtuin 1 (SIRT1) was decreased, in all Ecig-exposed groups compared with controls (Air:Air), with Ecig:Ecig group showing the greatest respective change for each. Electron paramagnetic resonance (EPR) spectroscopy revealed oxidative stress was the highest in the plasma of Ecig:Ecig group (P < 0.05) than the other groups. These data show that a double-hit exposure in adolescent or adult offspring results in a greater decline in cerebrovascular function, biomarkers of neuronal dysfunction, and increased circulation of EVs compared with a single-hit exposure.NEW & NOTEWORTHY These data add to the growing body of literature demonstrating that electronic cigarette (Ecig) use during pregnancy (even without nicotine) is not safe, and primes offspring to have worse cardiovascular health outcomes in early and adult life. A key finding from this work is that a second insult from direct vaping in offspring with prior in utero exposure induces greater vascular dysfunction, increased oxidative stress, and shows evidence of neuronal dysfunction compared with either direct- or maternal-only exposure.

[Harmful health effects of flavors in e-cigarettes]

BACKGROUND

Almost all e-cigarettes contain flavorings that make the product more attractive. In the evaluation of e-cigarettes on health, flavors have so far played a subordinate role.

METHOD

Selective literature search in PubMed, supplemented by legal regulations on the use of flavors in e-cigarettes.

RESULTS

Flavors make it easier to start using e-cigarettes and have a consumption-promoting effect. Deeper inhalation increases nicotine uptake and the absorption of toxic substances from the e-cigarette liquid. For some flavors, pathological effects have been demonstrated in addition to other toxic components of the e-cigarette. To date, no toxicological analyses are available for the vast majority of flavors contained in e-cigarettes.

CONCLUSIONS

The proven consumption-promoting effect and the health risks that can be extrapolated from preclinical data are significant for the political discussion of a ban on flavors for e-cigarettes, analogous to the ban on flavors in tobacco products already in force.

[Harmful health effects of flavors in e-cigarettes]

BACKGROUND

 Almost all e-cigarettes contain flavorings that make the product more attractive. In the evaluation of e-cigarettes on health, flavors have so far played a subordinate role.

METHOD

 Selective literature search in PubMed, supplemented by legal regulations on the use of flavors in e-cigarettes.

RESULTS

 Flavors make it easier to start using e-cigarettes and have a consumption-promoting effect. Deeper inhalation increases nicotine uptake and the absorption of toxic substances from the e-cigarette liquid. For some flavors, pathological effects have been demonstrated in addition to other toxic components of the e-cigarette. To date, no toxicological analyses are available for the vast majority of flavors contained in e-cigarettes.

CONCLUSIONS

 The proven consumption-promoting effect and the health risks that can be extrapolated from preclinical data are significant for the political discussion of a ban on flavors for e-cigarettes, analogous to the ban on flavors in tobacco products already in force.

Nicotine or marijuana vaping exposure during pregnancy and altered immune responses in offspring

Electronic nicotine delivery systems (ENDS) - which include electronic cigarettes or e-cigarettes, or simply e-cigs, and marijuana vaping have become increasingly popular. ENDS devices have been established as one of the tobacco quit methods and promoted to be safer compared to traditional tobacco cigarettes. Emerging evidence demonstrates that e-cigarette and marijuana vape use can be harmful, with potential associations with cancer. Herein, we summarize the level of evidence to date for altered immune response, with a focus on cancer risks in the offspring after maternal use of, or aerosol exposures from, ENDS or marijuana vape during pregnancy. From 27 published articles retrieved from PubMed, we sought to find out identified carcinogens in ENDS aerosols and marijuana vapor, which cross the placental barrier and can increase cancer risk in the offspring. Carcinogens in vaping aerosols include aldehydes, metals, tobacco-specific nitrosamines, tobacco alkaloids, polycyclic aromatic hydrocarbons, and volatile organic compounds. Additionally, there was only one passive vaping exposure case study on a human fetus, which noted that glycerol, aluminum, chromium, nickel, copper, zinc, selenium, and lead crossed from the mother to the offspring's cord blood. The carcinogens (metals) in that study were at lower concentrations compared to the mother's biological matrices. Lastly, we observed that in utero exposures to ENDS-associated chemicals can occur in vital organs such as the lungs, kidneys, brain, bladder, and heart. Any resulting DNA damage increases the risk of tumorigenesis. Future epidemiological studies are needed to examine the effects of passive aerosol exposures from existing and emerging electronic nicotine and marijuana products on developing offspring to cancer.

Adjuvant effect of inhaled particulate matter containing free radicals following house-dust mite induction of asthma in mice

INTRODUCTION

Exposures to particulate matter (PM) from combustion sources can exacerbate preexisting asthma. However, the cellular and molecular mechanisms by which PM promotes the exacerbation of asthma remain elusive. We used a house dust mite (HDM)-induced mouse model of asthma to test the hypothesis that inhaled DCB230, which are PM containing environmentally persistent free radicals (EPFRs), will aggravate asthmatic responses.

METHODS

Groups of 8-10-week-old C57BL/6 male mice were exposed to either air or DCB230 aerosols at a concentration of 1.5 mg/m3 4 h/day for 10 days with or without prior HDM-induction of asthma.

RESULTS

Aerosolized DCB230 particles formed small aggregates (30-150 nm). Mice exposed to DCB230 alone showed significantly reduced lung tidal volume, overexpression of the Muc5ac gene, and dysregulation of 4 inflammation related genes, Ccl11, Ccl24, Il-10, and Tpsb2. This suggests DCB230 particles interacted with the lung epithelium inducing mucous hypersecretion and restricting lung volume. In addition to reduced lung tidal volume, compared to respective controls, the HDM + DCB230-exposed group exhibited significantly increased lung tissue damping and up-regulated expression of Muc5ac, indicating that in this model, mucous hypersecretion may be central to pulmonary dysfunction. This group also showed augmented lung eosinophilic inflammation accompanied by an up-regulation of 36 asthma related genes. Twelve of these genes are part of IL-17 signaling, suggesting that this pathway is critical for DCB230 induced toxicity and adjuvant effects in lungs previously exposed to HDM.

CONCLUSION

Our data indicate that inhaled DCB230 can act as an adjuvant, exacerbating asthma through IL-17-mediated responses in a HDM mouse model.

Epigenetic and Long-Term Effects of Nicotine on Biology, Behavior, and Health

Tobacco and nicotine use are associated with disease susceptibility and progression. Health challenges associated with nicotine and smoking include developmental delays, addiction, mental health and behavioral changes, lung disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Increasing evidence suggests that nicotine-associated epigenetic changes may mediate or moderate the development and progression of a myriad of negative health outcomes. In addition, nicotine exposure may confer increased lifelong susceptibility to disease and mental health challenges through alteration of epigenetic signaling. This review examines the relationship between nicotine exposure (and smoking), epigenetic changes, and maladaptive outcomes that include developmental disorders, addiction, mental health challenges, pulmonary disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Overall, findings support the contention that nicotine (or smoking) associated altered epigenetic signaling is a contributing factor to disease and health challenges.

E-cigarettes and asthma in adolescents

PURPOSE OF REVIEW

E-cigarettes have been long purported to be a mechanism of harm reduction in current smokers. However, market expansion to adolescents has been aggressive, despite government interventions. Research examining the adverse effects of e-cigarettes in teens with asthma has been limited. We discuss the most recent data on the pulmonary manifestations of e-cigarettes use and exposure in adolescents with asthma.

RECENT FINDINGS

Adolescents with asthma are more likely to be e-cigarette users than those without asthma and more likely to have asthma exacerbations. Increased pulmonary inflammatory cytokines have been seen in e-cigarette users and mouse models. Yet, providers are not confident in e-cigarette screening and counselling despite acknowledging adolescents are using e-cigarettes regularly.

SUMMARY

Since the introduction of e-cigarettes into the United States market in 2007, adolescents use of these products has risen, even after a brief decline during the height of the COVID-19 pandemic. This review will describe the most recent studies on e-cigarette use trends, cytotoxicity of e-cigarette aerosol and associations with the diagnosis and symptoms of asthma. Knowledge gaps, advocacy efforts, evidence on e-cigarette cessation will be highlighted.

Exposure, Retention, Exhalation, Symptoms, and Environmental Accumulation of Chemicals During JUUL Vaping

Little is known about the chemical exposures that electronic cigarette (EC) users receive and emit during JUUL vaping and if exposures produce symptoms dose dependently. This study examined chemical exposure (dose), retention, symptoms during vaping, and the environmental accumulation of exhaled propylene glycol (PG), glycerol (G), nicotine, and menthol in a cohort of human participants who vaped JUUL "Menthol" ECs. We refer to this environmental accumulation as "EC exhaled aerosol residue" (ECEAR). Chemicals were quantified using gas chromatography/mass spectrometry in JUUL pods before and after use, lab-generated aerosols, human exhaled aerosols, and in ECEAR. Unvaped JUUL "Menthol" pods contained ∼621.3 mg/mL of G, ∼264.9 mg/mL of PG, ∼59.3 mg/mL of nicotine, ∼13.3 mg/mL of menthol, and ∼0.1 mg/mL of the coolant WS-23. Eleven experienced male EC users (aged 21-26) provided exhaled aerosol and residue samples before and after vaping JUUL pods. Participants vaped ad libitum for 20 min, while their average puff count (22 ± 6.4) and puff duration (4.4 ± 2.0) were recorded. The transfer efficiency of nicotine, menthol, and WS-23 from the pod fluid into the aerosol varied with each chemical and was generally similar across flow rates (9-47 mL/s). At 21 mL/s, the average mass of each chemical retained by the participants who vaped 20 min was 53.2 ± 40.3 mg for G, 18.9 ± 14.3 mg for PG, 3.3 ± 2.7 mg for nicotine, and 0.5 ± 0.4 mg for menthol, with retention deduced to be ∼90-100% for each chemical. There was a significant positive relationship between the number of symptoms during vaping and total chemical mass retained. ECEAR accumulated on enclosed surfaces where it could contribute to passive exposure. These data will be valuable to researchers studying human exposure to EC aerosols and agencies that regulate EC products.

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.

E-cigarette vapor exposure in utero causes long-term pulmonary effects in offspring

The in utero environment is sensitive to toxicant exposure, altering the health and growth of the fetus, and thus sensitive to contaminant exposure. Though recent clinical data suggest that e-cigarette use does no further harm to birth outcomes than a nicotine patch, this does not account for the effects of vaping during pregnancy on the long-term health of offspring. Pregnant mice were exposed to: 1) e-cigarette vapor with nicotine (PV + Nic; 2% Nic in 50:50 propylene glycol: vegetable glycerin), 2) e-cigarette vapor without nicotine [PV; (50:50 propylene glycol:vegetable glycerin)], or 3) HEPA filtered air (FA). Dams were removed from exposure upon giving birth. At 5 mo of age, pulmonary function tests on the offspring revealed female and male mice from the PV group had greater lung stiffness (Ers) and alveolar stiffness (H) compared with the FA group. Furthermore, baseline compliance (Crs) was reduced in female mice from the PV group and in male mice from the PV and PV + Nic groups. Lastly, female mice had decreased forced expiratory volume (FEV0.1) in the PV group, but not in the male groups, compared with the FA group. Lung histology revealed increased collagen deposition around the vessels/airways and in alveolar tissue in PV and PV + Nic groups. Furthermore, goblet hyperplasia was observed in PV male and PV/PV + Nic female mice. Our work shows that in utero exposure to e-cigarette vapor, regardless of nicotine presence, causes lung dysfunction and structural impairments that persist in the offspring to adulthood.