Electronic cigarette aerosols suppress cellular antioxidant defenses and induce significant oxidative DNA damage

Abstract

BackgroundElectronic cigarette (EC) aerosols contain unique compounds in addition to toxicants and carcinogens traditionally found in tobacco smoke. Studies are warranted to understand the public health risks of ECs.ObjectiveThe aim of this study was to determine the genotoxicity and the mechanisms induced by EC aerosol extracts on human oral and lung epithelial cells.MethodsCells were exposed to EC aerosol or mainstream smoke extracts and DNA damage was measured using the primer anchored DNA damage detection assay (q-PADDA) and 8-oxo-dG ELISA assay. Cell viability, reactive oxygen species (ROS) and total antioxidant capacity (TAC) were measured using standard methods. mRNA and protein expression were evaluated by RT-PCR and western blot, respectively.ResultsEC aerosol extracts induced DNA damage in a dose-dependent manner, but independently of nicotine concentration. Overall, EC aerosol extracts induced significantly less DNA damage than mainstream smoke extracts, as measured by q-PADDA. However, the levels of oxidative DNA damage, as indicated by the presence of 8-oxo-dG, a highly mutagenic DNA lesion, were similar or slightly higher after exposure to EC aerosol compared to mainstream smoke extracts. Mechanistically, while exposure to EC extracts significantly increased ROS, it decreased TAC as well as the expression of 8-oxoguanine DNA glycosylase (OGG1), an enzyme essential for the removal of oxidative DNA damage.ConclusionsExposure to EC aerosol extracts suppressed the cellular antioxidant defenses and led to significant DNA damage. These findings emphasize the urgent need to investigate the potential long-term cancer risk of exposure to EC aerosol for vapers and the general public.

Clinical peri‐implant parameters and inflammatory cytokine profile among smokers of cigarette, e‐cigarette, and waterpipe

“…The results of the present study agree with the findings of the previous studies that indicates the potential hazardous effects of tobacco in waterpipe and e‐cigs on oral cells. in vitro analyses suggests that aerosol from waterpipe and e‐cigs that are combined with flavoring agents has shown to enhance DNA injury and up‐regulation of a number of inflammatory proteins such as cyclooxygenase and prostaglandin E2 in gingival cells . Moreover, e‐cigs have the ability to enhance oxidative stress and generate accumulated glycation end products (AGEs) in cells of periodontal tissues .…”

“…in vitro analyses suggests that aerosol from waterpipe and e-cigs that are combined with flavoring agents has shown to enhance DNA injury and up-regulation of a number of inflammatory proteins such as cyclooxygenase and prostaglandin E2 in gingival cells. 19,20 Moreover, e-cigs have the ability to enhance oxidative stress and generate accumulated glycation end products (AGEs) in cells of periodontal tissues. 21 For this reason, these pathological mechanisms may also explain the unfavorable impact of waterpipe and e-cig usage on peri-implant structures.…”

Proinflammatory cytokine levels and peri‐implant parameters among cigarette smokers, individuals vaping electronic cigarettes, and non‐smokers

“…The explanation for the present results can be corroborated by recent results that indicate the potential hazardous effects of vaping e-cigs on oral epithelial cells and periodontal fibroblasts to e-cig vapor/aerosol with flavoring agents that enhances DNA damage and increases the expression of proinflammatory cytokines such as cyclooxygenase (COX)-2 and prostaglandin E 2 (PGE 2 ) in these cells. 21,22 Moreover, it has also been suggested that cigarette smoking and vaping e-cigs have the potential to induce oxidative stress and increases expression of advanced glycation end products (AGEs) and their receptors in cells, including gingival/periodontal tissues. 16 In this context, these mechanisms may also explain the detrimental effects of smoking tobacco and vaping on peri-implant tissues.…”

Electronic cigarettes increase endothelial progenitor cells in the blood of healthy volunteers

“…So far, in vitro studies have been contradictory [52]. Several adverse effects of e-cigarette vapor or e-liquid were found in different cell lines (endothelial, epithelial and fibroblastic cells) such as increased cytotoxicity and gene expression, decreased cell viability or reduced antioxidant defenses [61][62][63][64]. Other studies have shown little or no cytotoxicity [65][66][67].…”