E-cigarette aerosol exposure of pulmonary surfactant impairs its surface tension reducing function

Abstract

E-cigarette (EC) and vaping use continue to remain popular amongst teenage and young adult populations, despite several reports of vaping associated lung injury. This popularity is due in part to the vast variety of appealing flavours and nicotine concentrations easily accessible on the market. One of the first compounds that EC vapour comes into contact within the lungs during a deep inhalation is pulmonary surfactant. This lipid protein mixture lines the alveoli, reducing surface tension and preventing alveolar collapse. Impairment of surfactant’s critical surface tension reducing activity can contribute to lung dysfunction. Currently, information on how EC vapour impacts pulmonary surfactant remains limited. We hypothesized that exposure to EC vapour impairs the surface tension reducing ability of surfactant. BLES was used as a model surfactant in a direct exposure syringe system. BLES (2ml) was placed in a syringe (30ml) attached to an EC. Vapour was drawn into the syringe and then expelled, repeated 30 times. Biophysical analysis after exposure was completed using a constrained drop surfactometer (CDS). Minimum surface tensions increased after exposure to vapour. Variation in device used, addition of nicotine, or temperature of the vapour had no additional effect. Two e-liquid flavours, menthol and red wedding, had further detrimental effects, resulting in higher surface tension than the vehicle exposed BLES. Alteration of surfactant properties through interaction with vapour was observed with a basic e-liquid vehicle, however additional compounds produced by added flavourings appeared to be able to increase inhibition, however the exact mechanism remains unclear. In conclusion, EC vapour alters surfactant function through increases in minimum surface tension. This impairment can contribute to lung dysfunction and susceptibility to further injury.

E-cigarettes and asthma in adolescents

“…This study is notable for these effects within 5–7 days of e-cigarettes use initiation with e-cigarettes devices that did not contain nicotine or flavourings. Another recent study suggested that flavourings led to reduced alveolar surface tension [41]. Cahill et al .…”

“…This study is notable for these effects within 5-7 days of e-cigarettes use initiation with e-cigarettes devices that did not contain nicotine or flavourings. Another recent study suggested that flavourings led to reduced alveolar surface tension [41]. Cahill et al [42] described the effects of in-utero exposures to mint flavoured JUUL aerosol and found increased inflammation in allergic asthma induced progeny, with increased pro-inflammatory cytokines interleukin-5, 10 and 13 in the pups of exposed mothers.…”