Flavored e-cigarette liquids reduce proliferation and viability in the CaLU3 airway epithelial cell line

Introduction:
This article reports a study on the effects of various flavored e-cigarette liquids on lung epithelial cells. The study aimed to determine whether different flavors exhibited different toxicant profiles, and whether direct exposure to e-liquids could be used as a first-pass screening approach for determining relative e-liquid toxicity. The following key points summarize the study design and major findings.

Key Points:

* The study tested 13 different flavored e-liquids and their respective controls on a lung epithelial cell line (CaLU3) using the MTT assay to measure cell proliferation and viability.
* all flavors exhibited some degree of toxicity, with a group of four flavors showing significantly greater toxicity compared to the PG/VG control.
* aerosolized "vapor" from select e-liquids showed similar dose-dependent trends, suggesting that direct e-liquid exposures could be a valid first-pass screening approach.
* Gas chromatography-mass spectrometry identified diverse chemical constituents in the 13 flavored e-liquids beyond nicotine and PG/VG.
* The study found that aerosol generated at higher wattage exerted significant biological effects compared to lower wattage settings.
* The study also found that e-cigarette use in middle and high school students has tripled in recent years, and that there is concern about the potential negative effects of e-liquid flavors on the lung.

Main Message:
The study highlights the potential for some e-cigarette flavors to elicit more harmful effects than others, and the need for extensive testing of flavored e-liquids on a case-by-case basis to determine their potential for toxicity in the lung and elsewhere. With the growing popularity of e-cigarettes, particularly among young people, it is crucial to understand the potential health risks associated with their use. The study suggests that direct e-liquid exposures could be a valid first-pass screening approach for determining relative e-liquid toxicity, and that further research is needed to fully understand the potential health risks associated with e-cigarette use.

Rowell, Temperance R., Steven L. Reeber, Shernita L. Lee, Rachel a. harris, Rachel C. Nethery, amy h. herring, Gary L. Glish, and Robert Tarran. “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, no. 1 (July 1, 2017): L52–66. https://doi.org/10.1152/ajplung.00392.2016.