Flavored E-Cigarette Liquids Reduce Proliferation and Viability in the CALU3 Airway Epithelial Cell Line

Citation

Rowell, Temperance R.; Reeber, Steven L.; Lee, Shernita L.; Harris, Rachel A.; Nethery, Rachel C.; Herring, Amy H.; Glish, Gary L.; & Tarran, Robert (2017). Flavored E-Cigarette Liquids Reduce Proliferation and Viability in the CALU3 Airway Epithelial Cell Line. American Journal of Physiology: Lung Cellular and Molecular Physiology, 313(1), L52-66. PMCID: PMC5538872

Abstract

E-cigarettes are generally thought of as a safer smoking alternative to traditional cigarettes. However, little is known about the effects of e-cigarette liquids (e-liquids) on the lung. Since over 7,000 unique flavors have been identified for purchase in the USA, our goal was to conduct a screen that would test whether different flavored e-liquids exhibited different toxicant profiles. We tested the effects of 13 different flavored e-liquids (with nicotine and propylene glycol/vegetable glycerin (PG/VG) serving as controls) on a lung epithelial cell line (CALU3). Using the MTT assay as an indicator of cell proliferation/viability, we demonstrated a dose-dependent decrease of MTT metabolism by all flavors tested. However, a group of 4 flavors consistently showed significantly greater toxicity compared to the PG/VG control, indicating the potential for some flavors to elicit more harmful effects than others. We also tested the aerosolized 'vapor' from select e-liquids on cells and found similar dose-dependent trends, suggesting that direct e-liquid exposures are a justifiable first-pass screening approach for determining relative e-liquid toxicity. We then identified individual chemical constituents for all 13 flavors using gas chromatography-mass spectrometry. These data revealed that beyond nicotine and PG/VG, the 13 flavored e-liquids have diverse chemical constituents. Since all of the flavors exhibited some degree of toxicity and a diverse array of chemical constituents with little inhalation toxicity available, we conclude that flavored e-liquids should be extensively tested on a case-by-case basis to determine the potential for toxicity in the lung and elsewhere.

URL

http://dx.doi.org/10.1152/ajplung.00392.2016

Reference Type

Journal Article

Year Published

2017

Journal Title

American Journal of Physiology: Lung Cellular and Molecular Physiology

Author(s)

Rowell, Temperance R.
Reeber, Steven L.
Lee, Shernita L.
Harris, Rachel A.
Nethery, Rachel C.
Herring, Amy H.
Glish, Gary L.
Tarran, Robert

PMCID

PMC5538872