Impact of Electronic Nicotine Delivery Systems on Oral Mucosa: A Cytopathological and Molecular Study

Abstract

Background: The packaging and marketing of electronic cigarettes (e-cigs) often target younger demographics. This study aimed to evaluate gene expression in e-cig users through exfoliative cytology.

Methods: Samples were collected from 17 e-cig users and 10 nonsmokers as controls. Clinical data included age, gender, heart rate, oximetry, capillary blood glucose, carbon monoxide levels, sialometry, alcohol-related risk scores, alcohol consumption, and e-cig use parameters. Smears from the left tongue edge were obtained using a Rovers Orcellex Brush. The Papanicolaou method assessed epithelial maturation and cytological features, categorized from normal to conclusive for malignancy. Cellular composition, inflammation, microbial presence, and atypia were evaluated using a semiquantitative scoring system. Gene expression (p16, IL1-beta, CXCL8, TNF, and KRT13) was analyzed by RT-PCR. Statistical comparisons used the Mann-Whitney test, and correlations were assessed via Spearman's test (p ≤ 0.05).

Results: Fruit flavors were the most preferred. Some users were former smokers (average abstention: 3.15 months). Bacterial colonies were more prevalent in the e-cig group (64.7% vs. 20%, p = 0.085), mucus and inflammatory changes were found exclusively in e-cig users (p = 0.062). No significant differences were found in the Papanicolaou classification by gender (p = 0.904). Gene expression analysis showed a differential expression of p16 and TNF between the groups. Significant correlations were found between carbon monoxide and p16 expression (r = -0.41, p = 0.02), vaping sessions per day and p16 expression (r = -0.37, p = 0.02), and daily alcohol dose and TNF expression (r = -0.42, p = 0.04).

Conclusion: E-cigarette use may induce early molecular and cytological changes in the oral mucosa, affecting inflammation, immunity, and epithelial differentiation.