Cell-specific toxicity of short-term JUUL aerosol exposure to human bronchial epithelial cells and murine macrophages exposed at the air–liquid interface

Abstract

Backgroud JUUL, an electronic nicotine delivery system (ENDS), which first appeared on the US market in 2015, controled more than 75% of the US ENDS sales in 2018. JUUL-type devices are currently the most commonly used form of ENDS among youth in the US. In contrast to free-base nicotine contained in cigarettes and other ENDS, JUUL contains high levels of nicotine salt (35 or 59 mg/mL), whose cellular and molecular effects on lung cells are largely unknown. In the present study, we evaluated the in vitro toxicity of JUUL crème brûlée-flavored aerosols on 2 types of human bronchial epithelial cell lines (BEAS-2B, H292) and a murine macrophage cell line (RAW 264.7). Methods Human lung epithelial cells and murine macrophages were exposed to JUUL crème brûlée-flavored aerosols at the air–liquid interface (ALI) for 1-h followed by a 24-h recovery period. Membrane integrity, cytotoxicity, extracellular release of nitrogen species and reactive oxygen species, cellular morphology and gene expression were assessed. Results Crème brûlée-flavored aerosol contained elevated concentrations of benzoic acid (86.9 μg/puff), a well-established respiratory irritant. In BEAS-2B cells, crème brûlée-flavored aerosol decreased cell viability (≥ 50%) and increased nitric oxide (NO) production (≥ 30%), as well as iNOS gene expression. Crème brûlée-flavored aerosol did not affect the viability of either H292 cells or RAW macrophages, but increased the production of reactive oxygen species (ROS) by ≥ 20% in both cell types. While crème brûlée-flavored aerosol did not alter NO levels in H292 cells, RAW macrophages exposed to crème brûlée-flavored aerosol displayed decreased NO (≥ 50%) and down-regulation of the iNOS gene, possibly due to increased ROS. Additionally, crème brûlée-flavored aerosol dysregulated the expression of several genes related to biotransformation, inflammation and airway remodeling, including CYP1A1, IL-6, and MMP12 in all 3 cell lines. Conclusion Our results indicate that crème brûlée-flavored aerosol causes cell-specific toxicity to lung cells. This study contributes to providing scientific evidence towards regulation of nicotine salt-based products.

An updated overview of e-cigarette impact on human health

“…Recently, a commonly commercialized crème brûlée -flavoured aerosol was found to contain high concentrations of benzoic acid (86.9 μg/puff), a well-established respiratory irritant [ 88 ]. When human lung epithelial cells (BEAS-2B and H292) were exposed to this aerosol for 1 h, a marked cytotoxicity was observed in BEAS-2B but not in H292 cells, 24 h later.…”

“…When human lung epithelial cells (BEAS-2B and H292) were exposed to this aerosol for 1 h, a marked cytotoxicity was observed in BEAS-2B but not in H292 cells, 24 h later. However, increased ROS production was registered in H292 cells [ 88 ].…”

Effects of mango and mint pod-based e-cigarette aerosol inhalation on inflammatory states of the brain, lung, heart, and colon in mice

“…A majority of the current literature examined the cytotoxic effects of varying JUUL flavors (Crème Brulee, Cool Mint, Fruit Medley, Tobacco, Menthol, etc.) on cells of the respiratory system ( Pinkston et al, 2020 ; Ramirez et al, 2020 ; Pearce et al, 2020 ; Muthumalage et al, 2019 ; O’Farrell et al, 2021 ; Rao et al, 2020 ; Ghosh et al, 2021 ; Lamb et al, 2020 ). Most in vitro studies concluded that JUUL aerosols are cytotoxic and impair cell function ( Pinkston et al, 2020 ; Pearce et al, 2020 ; Muthumalage et al, 2019 ; O’Farrell et al, 2021 ; Rao et al, 2020 ; Ghosh et al, 2021 ).…”

Fundamentals of vaping-associated pulmonary injury leading to severe respiratory distress

“…Studies of VAPI often target specific biological processes to assess consequences for phenotypic or functional impact in cells, tissues, or animals. Assessment of vape fluid exposure in vitro is typically focused upon a particular cell type such as epithelial or vascular cells ( 24 , 25 , 26 , 27 , 28 ). Alternatively, in vitro studies of mixed cell cultures offer insight into disruption of structural interactions in “organoid” settings ( 29 ).…”