Analysis of the effect of disturbed flow on monocytic adhesion to endothelial cells

• Published in: Journal of biomechanics 2003-12, Vol.36 (12), p.1883-1895
• Main Authors: Chiu, Jeng-Jiann, Chen, Cheng-Nan, Lee, Pei-Ling, Tsair Yang, Cheng, Sheng Chuang, Han, Chien, Shu, Usami, Shunichi
• Format: Article
• Language: English
• Subjects: Adhesion molecule; Blood Flow Velocity; Cell adhesion & migration; Cell Adhesion - drug effects; Cell Adhesion - physiology; Cell Culture Techniques - methods; Cell Movement - drug effects; Cell Movement - physiology; Disturbed flow; E-Selectin; Endothelial cell; Endothelium, Vascular - cytology; Endothelium, Vascular - drug effects; Endothelium, Vascular - physiology; Flow Cytometry - instrumentation; Flow Cytometry - methods; Hemorheology - instrumentation; Hemorheology - methods; Humans; Intercellular Adhesion Molecule-1 - metabolism; Microfluidics - instrumentation; Microfluidics - methods; Micron-resolution particle image velocimetry; Monocyte adhesion; Monocytes - cytology; Monocytes - physiology; Proteins; Rheology - instrumentation; Rheology - methods; Shear stress; Tumor Necrosis Factor-alpha - pharmacology; Vascular Cell Adhesion Molecule-1 - metabolism
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/S0021-9290(03)00210-0

The preferential adhesion of monocytes to vascular endothelial cells (ECs) at regions near branches and curvatures of the arterial tree, where flow is disturbed, suggests that hemodynamic conditions play significant roles in monocyte adhesion. The present study aims to elucidate the effects of disturbed flow on monocyte adhesion to ECs and the adhesive properties of ECs. We applied, for the first time, the micron-resolution particle image velocimetry (μPIV) technique to analyze the characteristics of the disturbed flow produced in our vertical-step flow (VSF) chamber. The results demonstrated the existence of a higher near-wall concentration and a longer residence time of the monocytic analog THP-1 cells near the step and the reattachment point. THP-1 cells showed prominent adhesion to ECs pretreated with TNFα in the regions near the step and the reattachment point, but they showed virtually no adhesion to un-stimulated ECs. Pre-incubation of the TNFα-treated ECs with antibodies against intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin inhibited the THP-1 adhesion; the maximal inhibition was observed with a combination of these antibodies. Pre-exposure of ECs to disturbed flow in VSF for 24 h led to significant increases in their surface expressions of ICAM-1 and E-selectin, but not VCAM-1, and in the adhesion of THP-1 cells. Our findings demonstrate the importance of complex flow environment in modulating the adhesive properties of vascular endothelium and consequently monocyte adhesion in regions of prevalence of atherosclerotic lesions.