Assessing the impact of e-cigarette smoke on the vocal fold
Reviewed by Zach Shellman

While the use of electronic-cigarettes (e-cigs) is increasing rapidly, little is known about the effects this has on the health of vocal fold. In this translational research study, authors compared the effects of e-cig vapour and cigarette smoke on an in vitro model of the lamina propria of the vocal fold. An immortalised cell line of human vocal fold fibroblasts was cultured and exposed to varying concentrations of e-cig vapour extract and cigarette smoke extract for 24 hours via the cell culture medium. Cells lines were then harvested and assessed for cytotoxicity, extracellular matrix and inflammatory gene expression, and DNA damage. Cytotoxicity, as demonstrated by a reduction of viability below 70% against control, was significantly demonstrated in undiluted e-cig vapour while cigarette smoke vapour reduced viability to a greater degree and induced DNA damage. There were no changes in gene expression observed. Authors concluded that e-cig vapour is not inert and induced cytotoxicity in cultured human vocal fold fibroblasts, however it did not effect gene expression or DNA damage. Several limitations were observed. For example, a 24-hour exposure period was used to aid comparison to similar studies. However, this may miss earlier or later cellular changes, and the method of exposing cells in culture medium to vapour is likely inferior to using an organotypic air-liquid interface model. Additionally, epithelial cells are the first cell type to encounter inhaled vapours and are perhaps a more appropriate cell line to utilise here. Despite the limitations, the study does ultimately provide some of the first evidence of the detrimental effects of e-cigarette vapour on the vocal fold, and creates an important platform for further research.

Effects of Electronic (E)-cigarette Vapor and Cigarette Smoke in Cultured Vocal Fold Fibroblasts.
Martinez JD, Easwaran M, Ramirez D, Erickson-DiRenzo E.
LARYNGOSCOPE
2023;133(1):139-46.