E-cigarette aerosol exposure drives extracellular matrix gene dysregulation and collagen remodeling in gingival fibroblasts: An in vitro study

Background: E-cigarettes are promoted as less harmful alternatives to traditional tobacco products; however, their effects on periodontal tissues and orthodontic outcomes remain unexplored. This study aimed to investigate the impact of e-cigarette aerosol extract (ECAE) on human gingival fibroblasts (hGFs), focusing on cell viability, extracellular matrix (ECM) integrity, gene expression, and nicotine-protein interactions. Methods: Primary hGFs were exposed to ECAE (5-100%) prepared using a standardized puffing protocol. Cell viability was assessed at 24 and 72 h using the MTT assay. ECM-related gene expression with COL1A1, MMP1, MMP9, TIMP1 was quantified by qPCR. Collagen matrix organization and cellular morphology were evaluated using Masson's Trichrome staining and phase-contrast microscopy. Molecular docking was performed to assess nicotine interactions with ECM-associated proteins in 2D and 3D structures. Results: ECAE exposure resulted in a concentration- and time-dependent reduction in fibroblast viability, with significant cytotoxicity observed at concentrations ≥25%. qPCR showed downregulation of COL1A1 and TIMP1, and upregulation of MMP1 and MMP9, indicating a matrix-degradative gene profile. Masson's Trichrome staining revealed reduced collagen deposition and fibrotic band-like structures. Microscopy demonstrated morphological alterations, including cell shrinkage and vacuolation. Docking analysis indicated nicotine binding affinity to COL1A1 with -4.45 kcal/mol and TIMP1 with -5.08 kcal/mol, with stronger affinities for MMP1 with -5.42 kcal/mol and MMP9 (-6.55 kcal/mol), suggesting potential functional interference. Conclusion: and clinical models.