Atherosclerosis is a complex process involving progressive pathological events, including monocyte adhesion to the luminal endothelial surface. We have developed a functional in vitro adhesion assay using BioFlux microfluidic technology to investigate THP-1 (human acute monocytic leukaemia cell) monocyte adhesion to human aortic endothelial cells (HAECs). The effect of whole smoke conditioned media (WSCM) generated from University of Kentucky reference cigarette 3R4F, electronic cigarette vapour conditioned media (eVCM) from an electronic nicotine delivery system (ENDS) product (Vype ePen) and nicotine on monocyte adhesion to HAECs was evaluated. Endothelial monolayers were grown in microfluidic channels and exposed to 0–1500 ng/mL nicotine or nicotine equivalence of WSCM or eVCM for 24 h. Activated THP-1 cells were perfused through the channels and a perfusion, adhesion period and wash cycle performed four times with increasing adhesion period lengths (10, 20, 30 and 40 min). THP-1 cell adhesion was quantified by counting adherent cells. WSCM induced dose-dependent increases in monocyte adhesion compared to vehicle control. No such increases were observed for eVCM or nicotine. Adhesion regulation was linked to increased ICAM-1 protein expression. Staining of ICAM-1 in HAECs and CD11b (MAC-1) in THP-1 cells demonstrated adhesion molecule co-localisation in BioFlux plates. The ICAM-1 adhesion response to WSCM was downregulated by transfecting HAECs with ICAM-1 siRNA. We conclude that the BioFlux system is able to model human monocyte adhesion to primary human endothelial cells in vitro and WSCM drives the greatest increase in monocyte adhesion via a mechanism involving endothelial ICAM-1 expression.

动脉粥样硬化是一个复杂的过程，涉及进行性病理事件，包括单核细胞粘附到管腔内皮表面。我们开发了一种使用 BioFlux 微流体技术的功能性体外粘附试验，以研究 THP-1（人急性单核细胞白血病细胞）单核细胞对人主动脉内皮细胞 (HAEC) 的粘附。评估了来自肯塔基大学参考香烟 3R4F 的全烟条件培养基 (WSCM)、来自电子尼古丁传递系统 (ENDS) 产品 (Vype ePen) 的电子烟蒸气条件培养基 (eVCM) 和尼古丁对单核细胞粘附到 HAEC 的影响. 内皮单层在微流体通道中生长，并暴露于 0-1500 ng/mL 尼古丁或 WSCM 或 eVCM 的尼古丁等价物 24 小时。激活的 THP-1 细胞通过通道灌注，灌注、粘附期和洗涤循环进行四次，粘附期长度增加（10、20、30 和 40 分钟）。THP-1 细胞粘附通过计数粘附细胞来量化。与载体对照相比，WSCM 诱导单核细胞粘附的剂量依赖性增加。对于 eVCM 或尼古丁，没有观察到这种增加。粘附调节与 ICAM-1 蛋白表达增加有关。HAECs 中的 ICAM-1 和 THP-1 细胞中的 CD11b (MAC-1) 染色证明了粘附分子在 BioFlux 板中的共定位。通过用 ICAM-1 siRNA 转染 HAEC，ICAM-1 对 WSCM 的粘附反应被下调。