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.

吸烟和血流动力学是内皮功能障碍发生的关键刺激因素。作为吸烟的替代品，下一代烟草和尼古丁产品（NGP）现已被广泛使用。然而，人们对它们对内皮细胞潜在的促炎和动脉粥样硬化作用知之甚少。在这项研究中，我们分析了接触加热烟草产品 (HTP)、电子烟 (e-cig)、传统香烟 (3R4F) 和纯尼古丁的水性烟雾提取物 (AqE) 后内皮功能的关键参数。所有实验均在动脉粥样硬化高层流或致动脉粥样硬化低流量下使用原代人内皮细胞进行。

使用 3R4F（而非替代吸烟产品）治疗可通过 PI3K/AKT/eNOS(NOS3) 途径降低内皮细胞活力和伤口愈合能力。层流延迟了 3R4F 处理对细胞活力的有害影响。 3R4F刺激导致尼古丁浓度≥0.56 μg/ml时NRF2抗氧化防御系统激活，并增加其靶基因HMOX1和NQO1的表达。 HTP 治疗显示，尼古丁剂量≥1.68 μg/ml 时会诱导HMOX1和NQO1 ，而电子烟和尼古丁暴露没有影响。促炎基因分析显示，3R4F 治疗下ICAM1表达增加。 3R4F以剂量依赖性方式降低VCAM1表达； HTP 治疗具有相似但较温和的效果；电子烟和尼古丁治疗没有影响。 SELE表达由 3R4F 在静态条件下诱导。高层流阻止了这种上调。层流刺激导致CCL2 ( MCP-1 ) 下调。从这个下调水平来看，只有 3R4F 在较高浓度下增加了CCL2表达。最后，在静态条件下，所有成分都增加了单核细胞与内皮细胞的粘附。有趣的是，只有 3R4F 刺激才显示在易发生动脉粥样硬化的低流量下单核细胞粘附增加。

总之，所有产品类别都激活了抗氧化或促炎模式。 NGP 反应通常低于 3R4F 暴露细胞。此外，与 NGP 治疗相比，3R4F 刺激会导致内皮伤口愈合受损并诱导促炎表型。