E-Cigarette Aerosol Alters Pulmonary Surfactant Function

Abstract

Introduction: E-cigarette (EC) and vaping use continue to remain popular, particularly in young populations despite several clinical reports of vaping associated lung injury. One of the first compounds that EC aerosols comes into contact within the lungs during a deep inhalation is pulmonary surfactant. A complex mixture of lipids and proteins, surfactant reduces surface tension in the lungs maintaining compliance and preventing collapse. Currently, information on how EC aerosols impacts pulmonary surfactant remains limited, particularly in the in vivo scenario. We hypothesized that exposure to EC aerosol will impair the surface tension reducing ability of surfactant. Methods: In vitro EC aerosol exposure : Bovine Lipid Extract 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. The generated aerosol was drawn into the syringe and then expelled, repeated 30 times. In vivo EC aerosol exposure : Male and female Wistar rats were exposed to vehicle or menthol flavoured EC aerosol. Rats were exposed for 15 minutes for either a single or multiple (up to 8) exposures, with control animals receiving room air. Animals were euthanized and bronchoalveolar lavage was performed to collect surfactant. Analyzing surfactant function: Samples underwent dynamic compression and expansion, and biophysical analysis after exposure, completed using a constrained drop surfactometer (CDS). Results: Significant increases in minimum surface tensions were observed after exposure to EC aerosol across 20 compression/expansion cycles. Surfactant function was altered in vitro independent of vaping device, temperature, or inclusion of nicotine. Vehicle aerosol exposure produced alterations in surfactant properties, however addition of menthol flavouring significantly increased surface tensions compared to control and vehicle exposure. Preliminary in vivo studies indicate that aerosol exposure is well-tolerated by both male and female animals. Further experiments will analyze the function of surfactant isolated from these animals. Discussion: EC aerosols alter surfactant function through increases in minimum surface tension in vitro. This effect was more pronounced with menthol flavoured EC aerosol. It is anticipated that our in vivo experiments will corroborate these findings. Ultimately, impairment of surfactant due to EC aerosol exposure may contribute to lung dysfunction and susceptibility to further injury. Western University, NSERC, OGS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.