Electronic Nicotine Delivery System aerosol-induced Cell Death and Dysfunction in Macrophages and Lung Epithelial Cells.

Introduction:
This text summarizes an original research study on the effects of electronic nicotine delivery system (ENDS) aerosol exposure on lung epithelial cells and macrophages. The study used a laboratory-produced e-liquid and a direct aerosol exposure method to investigate the impacts on lung epithelial cells and macrophages.

Key Points:

* The study used a laboratory-produced e-liquid that eliminates the risk for variability in a commercial product and separates out the impact of the carrier components, propylene glycol (PG) and vegetable glycerin (VG), and the effects of nicotine.
* The laboratory-produced e-liquid reflects the most common base composition of e-liquid on the market, a 50/50 mix of PG and VG.
* Nicotine is added at a concentration of 18 mg/ml, which is on the low end of commercial e-liquids.
* The study used a direct aerosol exposure method, as it most closely recapitulates the exposure of an ENDS user.
* The study found that ENDS aerosol exposure led to apoptosis, secondary necrosis, and necrosis in lung epithelial cell models.
* In primary macrophages, ENDS aerosol exposure induced apoptotic, secondary necrotic, and in flammatory caspase –mediated cell death.
* Macrophage cell death is not dependent on the presence of nicotine.
* Exposure to ENDS aerosol containing nicotine inhibited nearly all phagocytic and greatly reduced the efferocytic abilities of primary macrophages.
* When challenged with a bacterial pathogen, there was decreased bacterial clearance.
* The presence of nicotine in the ENDS aerosol increased its toxicity and functional impact; however, nicotine exposure alone did not have any deleterious effects.

Main Message:
The study demonstrates that ENDS aerosol exposure could lead to increased epithelial cell and macrophage death in the lung and impair important macrophage functions that are essential for maintenance of lung function. These findings may indicate the potential danger of ENDS use and should be considered by relevant regulatory bodies.

Serpa GL, Renton ND, Lee N, Crane MJ, Jamieson aM. Electronic Nicotine Delivery System aerosol-induced Cell Death and Dysfunction in Macrophages and Lung Epithelial Cells. american journal of respiratory cell and molecular biology. 2020;63(3):306-316. doi:10.1165/rcmb.2019-0200OC