Effect of sub-chronic exposure to cigarette smoke, electronic cigarette and waterpipe on human lung epithelial barrier function.

Introduction:
This article presents a study on the effects of sub-chronic exposure to cigarette smoke (CS), electronic cigarette aerosol (EC), and tobacco waterpipe (TW) on human lung epithelial barrier function. The study uses an in vitro model of air-liquid interface exposure and investigates the barrier function/structural integrity of the epithelial monolayer.

Key Points:

* The study exposes human bronchial epithelial cells (hBECs) to CS, EC with 0% or 1.2% nicotine concentration, and TW for 10 days and 1-h/day, every other day, respectively.
* Exposure to CS, EC (1.2%), and TW results in decreased epithelial integrity. however, EC (0%) and TW exposures result in more moderate decreases compared to EC (1.2%) exposure.
* The study measures trans-epithelial electrical resistance (TEER), cilia beat frequency (CBF), cell velocity, and E-cadherin gene expression.
* CS and EC (1.2%) exposure significantly decreases TEER, reduces CBF, and increases cell velocity compared to air control.
* EC (1.2%) exposure significantly reduces E-cadherin gene expression, indicating a possible molecular mechanism for the disruption of bronchial epithelial cell barrier integrity.
* TW exposure tends to increase CBF but does not affect TEER or E-cadherin gene expression significantly.
* Further research is needed to address the molecular mechanism of TW and EC (0%) toxicity in chronic exposures.

Main Message:
The study provides evidence of the toxic effect of sub-chronic exposure to EC (1.2%) on human lung epithelial barrier function. The results support the need for more studies on the long-term health and harmful consequences of EC use. The study also highlights the importance of considering the concentration of nicotine in EC and the need for further research on TW and EC (0%) toxicity in chronic exposures. Overall, the study emphasizes the significance of lung epithelial barrier function in the context of tobacco product exposure and the importance of regulatory measures to protect public health.

Ghosh B, Reyes-Caballero h, akgün-Ölmez SG, et al. Effect of sub-chronic exposure to cigarette smoke, electronic cigarette and waterpipe on human lung epithelial barrier function. BMC pulmonary medicine. 2020;20(1):216. doi:10.1186/s12890-020-01255-y