Gingival Cell Mitochondrial Bioenergetics are Altered With e-cigarette Liquid Exposure

Objectives: E-cigarettes have been on the market for a decade. eCigs deliver pure nicotine and water vapor and were thus initially assumed to be less harmful than traditional smoking that contains thousands of known and unknown toxicants. A significant part of the oral pathology stemming from tobacco smoke exposure is oxidative stress, a function of altered mitochondrial function. However, analyses of mitochondrial efficiency are lacking in cells exposed to eCig liquid. Accordingly, we sought to determine the degree to which eCig liquid exposure affects gingival cell mitochondrial physiology.
Methods: Gingival epithelial cells (Ca9-22) were exposed to Cuttwood^TM, a national brand of eCig liquid at concentrations of zero, two, or four percent for 24 hours. Following treatment, cells were permeabilized and tested for various aspects of mitochondrial respiration.
Results: Specifically, we found evidence of a dose response, as increased concentrations of eCig exposure elicited a reduction in the rate at which the gingival mitochondria used oxygen. Moreover, the respiratory control ratio, a general indicator of mitochondrial “health” was significantly diminished with higher doses.
Conclusions: Altogether, these data suggest the mitochondria in oral gingival cells are compromised with eCig liquid exposure and further exploration is warranted to fully understand the pathogenicity of eCig use.