The effect of electronic cigarettes exposure on learning and memory functions: behavioral and molecular analysis

Association Between E-Cigarettes, Cognition and Mood in Adolescents

OBJECTIVE

Research has indicated potentially neutral or even positive cognitive effects of e-cigarette usage in adults, but whether these findings extend to adolescents remains uncertain. This study aimed to examine the interplay between e-cigarette use, mind wandering and self-efficacy, and mood.

METHOD

The responses of 432 adolescents aged 11-18 years from an online survey were analyzed. Among them, 88 adolescents had used e-cigarettes.

RESULTS

Adolescents who have used e-cigarettes reported poorer academic self-efficacy, t (430) = 3.26, 95% CI [1.12, 4.51], p < 0.001; greater mind-wandering tendencies t(430) = -3.38, 95% CI [-4.14, -1.10], p < 0.001; and greater severity of depression, t(430) = -3.38, p < 0.001, anxiety t(430) = -2.67, p = 0.01, and stress t(430) = -3.32, p < .001. Increased frequency of e-cigarette use was also associated with attitudes toward e-cigarette use, r (86) = 0.31, p = 0.003 and lower academic self-efficacy, r (86) = -0.27, p = .010. However, there was no significant correlation between frequency of use and mind-wandering. Further network analysis suggested negative relationships between frequency of e-cigarette use, academic self-efficacy and mind-wandering.

CONCLUSION

Our findings suggest a potential adverse impact of e-cigarette use on mind-wandering and academic confidence among adolescents. However, the direct or indirect relationship between e-cigarette use and these effects could not be definitively determined due to the cross-sectional survey design employed in our study. Nonetheless, our findings underscore the importance of considering developmental differences and the unique vulnerabilities of adolescents when assessing the impact of e-cigarette use.

Awareness of electronic cigarette industry practices and their associations with anti-electronic cigarette attitudes among susceptible US young adults

BACKGROUND

Public education exposing cigarette industry practices have been effective in changing attitudes and preventing smoking among young people. It is unclear how much young adults are aware of e-cigarette industry practices, and how this awareness relates to anti-e-cigarette attitudes. We examined demographic correlates of awareness of e-cigarette industry practices and anti-e-cigarette attitudes, and the association between awareness of these practices with anti-e-cigarette attitudes.

METHODS

A US sample of young adults aged 18-30 years who do not use commercial tobacco products but are susceptible to e-cigarette use were cross-sectionally surveyed through online panel services from August 2021 to January 2022. Respondents reported their demographics, awareness of cigarette industry practices, awareness of e-cigarette industry practices and their level of agreement with four anti-e-cigarette attitude statements. We used multivariable linear regressions to examine demographic associations and the relationship between awareness of e-cigarette industry practices with each anti-e-cigarette attitude, adjusting for demographics and awareness of cigarette industry practices.

RESULTS

Generally, Hispanic and Black young adults (vs White) and those with

DISCUSSION

Public education exposing e-cigarette industry practices may promote anti-e-cigarette attitudes among susceptible young adults who do not use commercial tobacco products. Future research should investigate the utility of anti-e-cigarette industry messaging.

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Key Words

• Denormalization
• Electronic nicotine delivery devices
• Prevention

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MESH Headings Collapse

Grants

• R00 CA272919 NCI NIH HHS
• U54 CA267735 NCI NIH HHS
• ZIA MD000006 Intramural NIH HHS

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Affiliation(s)

Lilianna Phan Division of Intramural Research, National Institute on Minority Health and Health Disparities, Bethesda, Maryland, USA Department of Community Health and Prevention, Dornsife School of Public Health and Division of Graduate Nursing, College of Nursing and Health Professions, Drexel University, Philadelphia, Pennsylvania, USA
Kelvin Choi Division of Intramural Research, National Institute on Minority Health and Health Disparities, Bethesda, Maryland, USA

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Nicotine, THC, and Dolutegravir Modulate E-Cigarette-Induced Changes in Addiction- and Inflammation-Associated Genes in Rat Brains and Astrocytes

E-cigarette use has been marketed as a safer alternative to traditional cigarettes, as a means of smoking cessation, and are used at a higher rate than the general population in people with HIV (PWH). Early growth receptor 2 (EGR2) and Activity-Regulated Cytoskeleton-Associated Protein (ARC) have a role in addiction, synaptic plasticity, inflammation, and neurodegeneration. This study showed that 10 days of exposure to e-cigarette vapor altered gene expression in the brains of 6-month-old, male, Sprague Dawley rats. Specifically, the e-cigarette solvent vapor propylene glycol (PG) downregulated EGR2 and ARC mRNA expression in frontal cortex, an effect which was reversed by nicotine (NIC) and THC, suggesting that PG could have a protective role against NIC and cannabis dependence. However, in vitro, PG upregulated EGR2 and ARC mRNA expression at 18 h in cultured C6 rat astrocytes suggesting that PG may have neuroinflammatory effects. PG-induced upregulation of EGR2 and ARC mRNA was reversed by NIC but not THC. The HIV antiretroviral DTG reversed the effect NIC had on decreasing PG-induced upregulation of EGR2, which is concerning because EGR2 has been implicated in HIV latency reversal, T-cell apoptosis, and neuroinflammation, a process that underlies the development of HIV-associated neurocognitive disorders.

Effects of e-vapour and high-fat diet on the immunohistochemical staining of nicotinic acetylcholine receptors, apoptosis, microglia and astrocytes in the adult male mouse hippocampus

The use of e-cigarettes/e-vapour, and the consumption of a high-fat diet (HFD), are two popular lifestyle choices associated with alterations in the hippocampus. This study, using a mouse model, investigated the effects of exposure to e-vapour (± nicotine) and HFD (43% fat) consumption, on the expression of nicotinic acetylcholine receptor (nAChR) subunits α3, α4, α7 and β2, apoptosis markers caspase-3 and TUNEL, microglial marker Iba-1, and astrocyte marker GFAP, in hippocampal subregions of dentate gyrus (DG) and cornu ammonis (CA) 1-3. The major findings included: (1) HFD alone had minimal effect with no consistent pattern or interaction between the markers, (2) E-vapour (± nicotine) predominantly affected the CA2 subregion, decreasing α7 and β2 nAChR subunits and Iba-1, (3) Nicotine e-vapour increased TUNEL across all subregions, and (4) HFD, in the presence of nicotine-free e-vapour, decreased caspase-3 and increased TUNEL across all regions, and decreased Iba-1 in the CA subregions, while HFD and nicotine-containing e-vapour, subregion specifically affected the α3, α4 and α7 nAChR subunits, with a protective effect against change in GFAP in the DG and Iba-1 in the CA1 and CA3. These findings highlight that e-vapour itself alters nAChRs, particularly in the CA2 subregion, associated with a decrease in neuroinflammatory response (Iba-1) across the whole hippocampus, and the addition of nicotine increases cell apoptosis across the whole hippocampus. HFD alone was not detrimental in our model, but in the presence of nicotine-free e-vapour, it differentially affected apoptosis, while the addition of nicotine increased nAChR subunits.

Acute Outcomes of Cigarette Smoke and Electronic Cigarette Aerosol Inhalation in a Murine Model

Cigarette smoking throughout life causes serious health issues in the lungs. The electronic cigarette (E-Cig) use increased, since it was first introduced in the world. This research work compared the short-term exposure consequences to e-cigarette vapor and cigarette smoke in male mice. Forty-five C57BL/6 mice were randomized into control (C) in an ambient air exposition cigarette smoke (CS) and aerosol electronic cigarette (EC), both were exposed to 120 puffs, 3 times/day during five days. Then, in the experimental protocol, the euthanized mice had their tissues removed for analysis. Our study showed that CS and EC resulted in higher cell influx into the airways, and an increase in macrophage counts in CS (209.25 ± 7.41) and EC (220.32 ± 8.15) when compared to C (108.40 ± 4.49) (p < 0.0001). The CS (1.92 ± 0.23) displayed a higher pulmonary lipid peroxidation as opposed to C (0.93 ± 0.06) and EC (1.23 ± 0.17) (p < 0.05). The EC (282.30 ± 25.68) and CS (368.50 ± 38.05) promoted increased levels of interleukin 17 when compared to C (177.20 ± 10.49) (p < 0.05). The EC developed shifts in lung histoarchitecture, characterized by a higher volume density in the alveolar air space (60.21; 55.00-65.83) related to C (51.25; 18.75-68.75) and CS (50.26; 43.75-62.08) (p =0.002). The EC (185.6 ± 9.01) presented a higher respiratory rate related to CS (133.6 ± 10.2) (p < 0.002). Therefore, our findings demonstrated that the short-term exposure to e-cig promoted more acute inflammation comparing to cigarette smoke in the ventilatory parameters of the animals.

Time course of changes in inflammatory and oxidative biomarkers in lung tissue of mice induced by exposure to electronic cigarette aerosol

Significance

Electronic cigarettes (e-cigarettes) have become a popular way to smoke all over the world. Chronic exposure to e-cigarette aerosol may influence lung health. This study uses an animal model to explore the time course of the effect of exposure to e-cigarette aerosols on the lung.

Methods

Lung samples were collected after exposure of Balb/c mice to e-cigarette aerosols for 1 h/day (6 times/week) for 1, 2 and 4 weeks and compared to sham-exposed controls. Examined biomarkers including inflammatory cells, tumor necrosis factor α (TNFα), interleukin-6 (IL-6), interleukin-10 (IL-10), reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), and Thiobarbituric acid reactive substances (TBARS).

Results

Exposure of animals to e-cigarette aerosols induced significant increases (P < 0.05) in total inflammatory cells, eosinophils, macrophages and TNFα in the lung tissue after 1, 2 and 4 weeks of exposure. Furthermore, level of IL-10 significantly decreased, whereas levels of neutrophils and basophils significantly increased (P < 0.05) after 1 week of exposure. Exposure of animals to e-cigarette aerosol also induced significant decreases (P < 0.05) in the GSH/GSSG ratio, and GPx levels after 2 and 4 weeks of exposures. The activity of catalase was also reduced (P < 0.05) after 4 weeks of exposure. Level of TBARS showed a trend of elevation with time and it reached a significant elevation after 4 weeks (P < 0.01).

Conclusion

Current results indicate that inhalation of unflavored e-cigarette aerosol might be associated with inflammation in lung tissue that worsen as the duration of exposure increases. Further experiments including more time points, histopathology and pulmonary physiology experiments are needed to confirm the current results.