Abstract
We evaluated the effect of multiple exposures to electronic cigarettes on human oral mucosa structure and proinflammatory cytokine secretion. A 3D air-liquid interface human gingival mucosa was produced and exposed 10 min twice a day for 2 and 4 days for a total of 4 or 8 exposure times to e-cigarette aerosol. The vaped e-liquid contained 18 mg/ml of nicotine. Results show that 4 and 8 exposures to the e-cigarettes with and without nicotine-induced structural tissue damage, decreased Laminin and type IV collagen production but increased the secretions of several metalloproteinases (MMPs), and lactate dehydrogenase (LDH). The e-cigarette reduced the number of proliferative epithelial cells, as ascertained by the low number of Ki-67+ cells. Exposure to e-cigarette aerosol increased proinflammatory cytokines IL-6, IL-8, GM-CSF, MCI-1, and TNFα. However, the e-cigarette aerosol effects were lower than combustible cigarette smoke (CS). Although e-cigarette aerosols produced less tissue damage than CS, they still induce critical damage to the engineered human gingival mucosa. E-cigarette users and oral health professionals should be aware of the potential adverse effects of e-cigarettes.