Introduction:
This article reports a study comparing the oxidative stress and cytotoxicity of cigarette smoke and e-cigarette aerosol extracts (aqE) using an in vitro model of the airway epithelium. The study used a standardized machine puffing regime, industry-recognized reference cigarettes, and qC measurements on the aqE stock solutions. The aqE exposure concentrations were based on range-finding experiments, and the concentration-dependent activation of all assay endpoints was observed. This study aimed to investigate the potential of this technique to detect in vitro epithelial responses to captured e-cigarette vapors, puff-matched to cigarette smoke, up to a maximum 0.5 puffs/mL.
Key Points:
* The study used a standardized machine puffing regime, industry-recognized reference cigarettes, and qC measurements on the aqE stock solutions.
* The aqE exposure concentrations were based on range-finding experiments, and the concentration-dependent activation of all assay endpoints was observed.
* The 3R4F aqE exposure concentrations demonstrated that NCI-h292 cells generated oxidant species, showed antioxidant depletion, and initiated an antioxidant transcriptional response, indicating that the cells had entered into a state of oxidative stress.
* The e-cigarette aqE showed no harmful pro-oxidant effects, and the assay responses were either below the limit of detection or the chemical drivers of the assay endpoints were absent or present in insufficient concentrations.
* The absence of detectable epithelial cellular stress responses to the e-cigarette aqE demonstrated in this study may have resulted partly from the much reduced carbonyl levels and absence of CO in the e-cigarette vapor and/or tar in aqE.
* The glutathione ratio was used as a marker for redox status and oxidative stress, providing a reliable indicator of cellular health.
* The study also demonstrated a link between the concentration-dependent lowering of GSh levels and levels of smoke-related carbonyls, such as formaldehyde, acetaldehyde, and acrolein, in aqE.
Main Message:
The study found that e-cigarette aqE did not induce oxidative stress or cytotoxicity under comparable experimental conditions used for cigarette smoke exposure. The absence of detectable epithelial cellular stress responses to the e-cigarette aqE demonstrated in this study may have resulted partly from the much reduced carbonyl levels and absence of CO in the e-cigarette vapor and/or tar in aqE. These findings suggest that e-cigarette use may be a safer alternative to tobacco smoking regarding oxidative stress and cytotoxicity. however, further studies are required to investigate the potential effects of e-cigarette use on other health outcomes.
Citation
Taylor, Mark, Tony Carr, Oluwatobiloba Oke, Tomasz Jaunky, Damien Breheny, Frazer Lowe, and Marianna Gaça. “E-Cigarette aerosols Induce Lower Oxidative Stress in Vitro When Compared to Tobacco Smoke.” Toxicology Mechanisms and Methods 26, no. 6 (July 23, 2016): 465–76. https://doi.org/10.1080/15376516.2016.1222473.
