Table 2.
Summary of effects of vaping on primary pulmonary cells in vitro
| Observed effect | Cell type | E-liquids | Delivery methods |
|---|---|---|---|
| Airway surface dehydration and/or inhibition of CFTR ion transport96 113 114 | Human bronchial epithelia | Red oak e-liquid, 1% nicotine; e-liquid ±36 mg/mL nicotine | Aerosol delivery to cultures |
| Decreased ciliary beating83 96 114 115 | Human bronchial and nasal epithelia | e-liquid ±36 mg/mL nicotine; e-liquid ±36 mg/mL nicotine | Aerosol delivery to cultures |
| Increased MUC5AC mucin production55 | Human bronchial epithelia | PG/VG (nicotine independent) | Aerosol delivery to cultures |
| Decreased cell viability/increased cellular toxicity86 115-117 | Human bronchial epithelia, alveolar macrophages, airway smooth muscle, NK cells | Several commercial e-liquids, all at 12 mg/mL nicotine; vaped e-liquid condensate and/or aerosol from second and third generation devices | Liquid and aerosol delivery to cultures |
| Increased cytokine secretion86 118 | Human alveolar macrophages, bronchial epithelia, peripheral blood neutrophils, NK cells | Several flavored nicotine-free e-liquids; commercial e-liquids ±24 mg/mL nicotine | Vaped e-liquid condensate from third generation device |
| Altered membrane fluidity55 | Human bronchial epithelia | PG/VG (nicotine independent) | Aerosol and liquid delivery to cultures |
| Decrease in barrier function (resistance)119 120 | Human, mouse, and rat endothelia; human/COPD bronchial epithelia | Commercial e-liquids; up to 25 mM nicotine; USA tobacco flavor, 24 mg/mL nicotine | Condensate generated |
| Impaired phagocytosis86 116 | Human alveolar macrophages and peripheral blood neutrophils | Several flavored nicotine-free e-liquids; commercial e-liquids ±24 mg/mL nicotine | Vaped e-liquid from third generation device |
| Impaired mitochondrial function and reduced glycolysis115 | Human bronchial epithelia | Cinnamaldehyde flavored e-liquid | Vaped e-liquid directly and as condensate from third generation device |
| p38 MAPK and/or ERK activation96 118 119 | Human bronchial epithelia; human, mouse, and rat endothelia; human neutrophils | e-liquid ±36 mg/mL nicotine; commercial e-liquids; up to 25 mM nicotine; commercial e-liquids ±24 mg/mL nicotine | Aerosol delivery to cultures; condensate generated using second or third generation devices |
| Induction of apoptosis and necrosis116 | Human alveolar macrophages | Commercial e-liquids ±36 mg/mL nicotine | Condensate generated using second generation device |
| Changes in gene expression121 | Human bronchial epithelia | VitroCell System | Increased genes involved in oxidative and xenobiotic stress markers of ROS; decreased genes involved in ciliary function |
| No change in barrier function (resistance), CBF, FOXJ1, MUCAC; essentially no change in RNA transcript expression122 * | Human bronchial epithelia | “Blended tobacco” e-liquid 18 mg/mL nicotine | Vype E-pen; cells exposed to vapor in BAT exposure chambers |
| No effect on ASL height, ion transport or CBF123 * | Human bronchial epithelia | Avail Vapor “Tobacco Row” 18 mg/mL nicotine | Aerosol generated using third generation device |
ASL=airway surface liquid; BAT=British American Tobacco; CBF=ciliary beat frequency; COPD=chronic obstructive pulmonary disease; CSTR=cystic fibrosis transmembrane conductance regulator; NK=natural killer; PG=propylene glycol; ROS=reactive oxygen species; VG=vegetable glycerin.
*
Studies funded by tobacco industry.