Salivary Proteomics Reveals Oxidative Markers in E‑Cigarette Users

Electronic cigarettes (e-cigs) have become increasingly
popular,
particularly among younger populations. This study aimed to evaluate
the salivary proteome of e-cig users and identify potential alterations
in saliva composition. Participants were divided into the Electronic
Cigarette Group (EG, n = 25 regular exclusive users)
and the Control Group (CG, n = 25 nonsmokers/nonusers),
matched by sex and age. Clinical examination and unstimulated saliva
collection were performed for proteomic analysis. A total of 1,773
proteins were identified, of which 92 had consistent quantitative
values between groups. Comparison using the Wilcoxon–Mann–Whitney
test revealed 22 proteins with differential abundance (p ≤ 0.05), most of them up-regulated in EG, notably Peroxiredoxin-1,
while few showed decreased abundance. Functional enrichment analysis
highlighted pathways related to keratinization, keratinocyte differentiation,
and stress response, suggesting activation of cellular defense and
adaptation mechanisms. These results indicate that e-cig aerosol exposure
induces biological alterations in the oral environment, including
modulation of proteins linked to oxidative stress and epithelial integrity.
Overall, the findings emphasize the need for long-term monitoring
of e-cig users and reinforce the importance of educational strategies
to counter the perception of low risk associated with electronic cigarettes.