Comparative study of the effects of cigarette smoke versus next generation tobacco and nicotine product extracts on endothelial function

• Published in: Redox biology Vol. 47; p. 102150
• Main Authors: Giebe, Sindy, Hofmann, Anja, Brux, Melanie, Lowe, Frazer, Breheny, Damien, Morawietz, Henning, Brunssen, Coy
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2021; Elsevier
• Subjects: 3R4F aqueous cigarette smoke extract (3R4F AqE); Electronic cigarette (e-cig); Electronic Nicotine Delivery Systems; Endothelial Cells; Endothelial dysfunction; Endothelium, Vascular; Heated tobacco product (HTP); Humans; Laminar flow; Monocyte adhesion; Next generation tobacco and nicotine products (NGP); Nicotiana; Nicotine; Phosphatidylinositol 3-Kinases; Research Paper; Smoke; Smoking - adverse effects; Tobacco Products; Wound healing; Electronic cigarette (e-cig); Wound healing; 3R4F aqueous cigarette smoke extract (3R4F AqE); Laminar flow; Endothelial dysfunction; Monocyte adhesion; Heated tobacco product (HTP); Next generation tobacco and nicotine products (NGP)
• DOI: 10.1016/j.redox.2021.102150
• ISSN: 2213-2317

Tobacco smoking and hemodynamic forces are key stimuli for the development of endothelial dysfunction. As an alternative to smoking, next generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their potential pro-inflammatory and atherogenic effects on the endothelium. In this study, we analyzed key parameters of endothelial function after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine. All experiments were performed under atheroprotective high laminar or atherogenic low flow with primary human endothelial cells. Treatment with 3R4F, but not alternative smoking products, reduced endothelial cell viability and wound healing capability via the PI3K/AKT/eNOS(NOS3) pathway. Laminar flow delayed detrimental effects on cell viability by 3R4F treatment. 3R4F stimulation led to activation of NRF2 antioxidant defense system at nicotine concentrations ≥0.56 μg/ml and increased expression of its target genes HMOX1 and NQO1. Treatment with HTP revealed an induction of HMOX1 and NQO1 at dosages with ≥1.68 μg/ml nicotine, whereas e-cig and nicotine exposure had no impact. Analyses of pro-inflammatory genes revealed an increased ICAM1 expression under 3R4F treatment. 3R4F reduced VCAM1 expression in a dose-dependent manner; HTP treatment had similar but milder effects; e-cig and nicotine treatment had no impact. SELE expression was induced by 3R4F under static conditions. High laminar flow prevented this upregulation. Stimulation with laminar flow led to downregulation of CCL2 (MCP-1). From this downregulated level, only 3R4F increased CCL2 expression at higher concentrations. Finally, under static conditions, all components increased adhesion of monocytes to endothelial cells. Interestingly, only stimulation with 3R4F revealed increased monocyte adhesion under atherosclerosis-prone low flow. In conclusion, all product categories activated anti-oxidative or pro-inflammatory patterns. NGP responses were typically lower than in 3R4F exposed cells. Also, 3R4F stimulation led to an impaired endothelial wound healing and induced a pro-inflammatory phenotype compared to NGP treatment. [Display omitted] •3R4F, but not NGP and nicotine, impair endothelial cell viability and wound healing.•All tested product categories induce anti-oxidative enzymes and adhesion molecules in HUVEC.•Only 3R4F increases monocyte adhesion to endothelial cells under low laminar flow.•Protective effects of high laminar flow counteract with deleterious effects of smoking.