"It is the One Thing that has Worked": facilitators and barriers to switching to nicotine salt pod system e-cigarettes among African American and Latinx people who smoke: a content analysis

Vaping-Induced Proteolysis Causes Airway Surface Dehydration

Proteases such as neutrophil elastase cleave and activate the epithelial sodium channel (ENaC), causing airway dehydration. Our current study explores the impact of increased protease levels in vapers' airways on ENaC activity and airway dehydration. Human bronchial epithelial cultures (HBECs) were exposed to bronchoalveolar lavage fluid (BALF) from non-smokers, smokers and vapers. Airway surface liquid (ASL) height was measured by confocal microscopy as a marker of hydration. ENaC cleavage was measured by Western blotting. Human peripheral blood neutrophils were treated with a menthol-flavored e-liquid (Juul), and the resulting secretions were added to HBECs. BALF from smokers and vapers significantly and equally increased ENaC activity and decreased ASL height. The ASL height decrease was attenuated by protease inhibitors. Non-smokers' BALF had no effect on ENaC or ASL height. BALF from smokers and vapers, but not non-smokers, induced ENaC cleavage. E-liquid-treated neutrophil secretions cleaved ENaC and decreased ASL height. Our study demonstrated that elevated protease levels in vapers' airways have functional significance since they can activate ENaC, resulting in airway dehydration. Lung dehydration contributes to diseases like cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD) and asthma. Thus, our data predict that vaping, like smoking, will cause airway surface dehydration that likely leads to lung disease.

It's addiction at this Point": A qualitative examination of youth E-cigarette use trajectory in the United States

E-cigarettes (electronic cigarettes) have been the most used tobacco product among US youth since 2014, reaching a plateau during the COVID-19 pandemic. Youth e-cigarette use is associated with negative health consequences such as impaired cognitive functioning. For many, the COVID-19 pandemic altered social interactions, harm perceptions, and product availability. This changed the frequency and locations in which youth use e-cigarettes. To better understand youth e-cigarette use, we need more information on factors that can alter e-cigarette use, specifically, how the pandemic changed e-cigarette use among youth. In 2020-2021, we conducted online, individual interviews with 19 youth (aged 13-17) e-cigarette users living in the US to explore how COVID-19 impacted their e-cigarette use. Youth described a progression of e-cigarette use from initial experimentation, regular social use, and ultimately to nicotine addiction demonstrated by individual use in isolation. Many youth initiated e-cigarette use due to influences by friends or family members. Youth discussed progression to social use, with social interactions as an important reason for use and an avenue for expanding one's knowledge of e-cigarettes. After a period of time, youth began to recognize that the social interactions mattered less, suggesting to them that they had become addicted. This realization became more apparent during COVID-19, which changed how youth used e-cigarettes, especially around where use was occurring, health concerns, and use behavior and frequency. In our interviews, youth trajectory began with an initiation with family and friends, progressed to social use, and eventually developed to addiction, at which point social use was no longer the primary motivation for e-cigarette use. Understanding the trajectory of e-cigarette use will allow for effective interventions that reduce harm to youth from e-cigarette use.

Toward Better Characterization of a Free-Base Nicotine Fraction in e-Liquids and Aerosols

Given that nicotine salts are a growing market, methods are needed to characterize nicotine forms in e-cigarette vaping products. By lowering the free-base nicotine fraction (α_fb) in favor of protonated forms, the addition of organic acids to the e-liquid mix greatly modulates nicotine pharmacokinetics and improves vapers' craving. This research investigated (1) the performance of pH measurement, liquid-liquid extraction (LLE), and acid/nicotine molar ratio calculation methods for α_fb estimation in 6 nicotine benzoate and nicotine salicylate e-liquids and (2) nicotine protonation in the aerosol post vaporization. Aerosols were generated with a JUUL device and another mod-pod on a vaping machine to assess device effects. E-liquid and aerosol samples were then analyzed after further analytical optimization of previous methods and careful consideration of biases. Globally, performances were comparable between methods. α_fb accounted for less than 5% of nicotine content regardless of experimental conditions. α_fb were consistent between e-liquids and aerosols irrespective of e-cigarette devices. Hence, e-liquids are adequate surrogates for aerosols, facilitating the establishment of regulations. pH measurement is one of the most used methods and enables the establishment of relative scales for e-liquid classification but lacks automation possibility. Until now, the extent of sample dilution remained arbitrary. The dilution factor was fixed at 10, as usually achieved, since no effect of dilution was noted. pH values ranged from 5.3 to 6.3 in accordance with the literature. By contrast, LLE relies on the specificity of organic solvent for free-base nicotine extraction, causing discrepancies in previous studies. Here, the results were similar to α_fb values from pH determination. Yet, LLE presented the highest variability and was the most time-consuming protocol. Finally, α_fb calculation from molar ratio was the most robust and versatile method. Estimations can be made in silico from reported composition data and/or after liquid chromatography routine analysis.