Effects of E-Cigarette Refill Liquid Flavorings with and without Nicotine on Human Retinal Pigment Epithelial Cells: A Preliminary Study

Abstract

Smoking is an etiologic factor for age-related macular degeneration (AMD). Although cigarette smoke has been extensively researched for retinal pigment epithelial (RPE) cell degeneration, the potential for adverse effects on the retinal epithelium following exposure to flavored e-cigarette refill liquid has never been explored. In this preliminary study, we have examined the effects of 20 e-liquids (10 different flavored nicotine-free and 10 nicotine-rich e-liquids) used in e-cigarettes on the metabolic activity, membrane integrity, and mitochondrial membrane potential of RPE cells. Our results showed that of the flavors studied over the concentration range: 0.5, 1, and 2% v/v for a duration of 48 h, cinnamon was the most toxic and menthol was the second most toxic, while other flavors showed lesser or no cytotoxicity. The presence of nicotine augmented cytotoxicity for cinnamon, menthol, strawberry, vanilla, and banana while for other flavors there was no synergism. Together, our results demonstrate that exposure of RPE to flavored e-cigarette refill liquids caused significant cytotoxicity and may be a risk factor for the development of retinal pathogenesis, although further in-depth studies are necessary.

Carbonyl Profiles of Electronic Nicotine Delivery System (ENDS) Aerosols Reflect Both the Chemical Composition and the Numbers of E-Liquid Ingredients–Focus on the In Vitro Toxicity of Strawberry and Vanilla Flavors

“…Moreover, in a crossover study, the serum levels of soluble NOX2 and of 8-isoprostane, which are markers of reactive oxidants and oxidative stress, respectively, were increased 30 min after inhaling 9 puffs of e-cig aerosol when compared to levels measured before the vaping session [ 52 ]. Overall, our data ( Figure 4 ) along with other experimental [ 13 , 56 , 57 , 58 ] and epidemiological [ 52 , 59 ] evidence suggest that acute inhalation of e-cig aerosol can disrupt the redox state of pulmonary cells, which can translate into early adverse effects that can lead to the development of pulmonary diseases [ 54 ].…”

“…These results highlight that strawberry flavor is more cytotoxic than many other flavored e-liquids. Likewise, increased in vitro toxicity of strawberry-flavored e-liquids have been demonstrated in several studies using different cell lines, including CALU3 airway epithelial cells [ 13 , 56 ], pulmonary artery smooth muscle cells [ 57 ], and retinal pigment epithelial cells [ 58 ]. Our data show that this is also the case for BEAS-2B cells exposed at the ALI to heated and aerosolized strawberry-flavored e-cig aerosols generated by a third-generation device ( Figure 4 ).…”

The Current Scenario Regarding the Narrative Advancement of Oral Cancer

“…Early detection is essential because cancer treatments may be more effective and involve fewer complications. Tobacco, smokeless tobacco [42][43][44] Probiotics [45] Alcohol consumption Chemoprevention…”

Comparative Cytotoxicity of Menthol and Eucalyptol: An In Vitro Study on Human Gingival Fibroblasts

“…Menthol-flavored e-cigarette liquids significantly induce cell death (IC 50 : 1.45 ± 0.14%) in middle ear epithelial cells and may be a risk factor for the development of otitis media [ 31 ]. There is also a synergism between nicotine and menthol that increases their cytotoxicity in retinal pigment epithelial cells, so they would also constitute a possible risk factor for retinal pathology [ 32 ]. Lastly, the cytotoxicity of e-cigarettes does not appear to be directly dependent on menthol—neither liquid nicotine nor ROS formation—on human vascular endothelial cells [ 33 ].…”