E-Cigarettes induce expression of procoagulant tissue factor in cultivated human endothelial cells

Background: E-cigarettes (ECIG) are proposed as an alternative for regular tobacco users with less dangerous effects for health. Several studies demonstrated that ECIG exert deleterious cardiovascular effects and promote platelet dependent thrombosis. However, ECIG role on Tissue Factor-dependent thrombosis is still unknown. Dysfunctional endothelial cells (ECs) are known to express Tissue Factor (TF) on their surface. Aim of the present study was to investigate whether ECIG might promote TF expression in ECs, shifting them to a pro thrombotic phenotype. Methods: Human Umbilical Vein Endothelial Cells (HUVEC) were incubated with increasing doses of ECIG (commercially available and mix of propylene glycol/vegetable glycerine/nicotine 18 mg/mL) up to 1.8 mg/mL. TF gene expression and protein levels were assessed at different time points by Real Time PCR and Western Blot, respectively. TF surface expression and activity were also measured by FACS analysis and coagulation assay. Finally, NF-kB translocation was investigated as possible mechanism of action. Potential protective effects by Rosuvastatin were also investigated. Results: ECIG significantly increased TF expression at both gene and protein levels in a time and dose dependent manner. Surface expression and procoagulant activity were increased as well. These phenomena appeared modulated by the NF-κB pathway. Rosuvastatin reduced ECIG effects on TF-mRNA. Conclusions: Although in vitro, we indicate that ECIG promote a pro thrombotic phenotype in ECs via expression of functional TF. Data of the present study permit to shed a brighter light on the still partially unresolved issue about the role of ECIG in development of cardiovascular diseases suggesting that they might represent a potential risk factor for thrombotic cardiovascular events.