Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids are Cytotoxic for human Vascular Endothelial Cells

Introduction:
This article provides an in-depth analysis of the toxicological effects of e-cigarette vapors from various brands and liquids. The study aims to compare e-cigarette vapor toxicity to conventional cigarette smoke and to identify the key elements contributing to e-cigarette vapor toxicity. The researchers used an adapted version of a cigarette smoke constituent sampling device to collect the hydrophilic fraction of e-cigarette vapor and expose human umbilical vein endothelial cells (hUVECs) to the mixture of compounds present in the vapor of different single-use e-cigarettes, refillable e-cigarettes, and e-cigarettes with exchangeable liquid cartridges.

Key Points:

* Conventional cigarette smoke extract showed the most severe impact on endothelial cells.
* Some e-cigarette vapor extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes.
* The vapors generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity.
* E-cigarette vapor-mediated induction of oxidative stress was significant in one out of the 11 analyzed vapors.
* There is a high variability in the acute cytotoxicity of e-cigarette vapors depending on the liquid and on the e-cigarettes used.
* Some products showed toxic effects close to a conventional high-nicotine cigarette.
* Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapor toxicity.

Main Message:
The study reveals that some e-cigarette vapor extracts can be as toxic as conventional high-nicotine cigarettes, with substantial differences in toxicity between different liquids and e-cigarettes. The findings highlight the urgent need for regulatory measures to ensure the safety and quality of e-cigarette liquids and devices. While e-cigarettes are often promoted as a safer alternative to traditional cigarettes, this study suggests that they may still pose significant health risks. Therefore, it is crucial to regulate e-cigarettes and their components to protect consumers from potential harm.

Putzhammer, Raphaela, Christian Doppler, Thomas Jakschitz, Katharina heinz, Juliane Förste, Katarina Danzl, Barbara Messner, and David Bernhard. “Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids are Cytotoxic for human Vascular Endothelial Cells.” Edited by Gianfranco Pintus. PLOS ONE 11, no. 6 (June 28, 2016): e0157337. https://doi.org/10.1371/journal.pone.0157337.