title: Analysis of the effect of disturbed flow on monocytic adhesion to endothelial cells.
abstract: 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 (microPIV) 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 TNFalpha in the regions near the step and the reattachment point, but they showed virtually no adhesion to un-stimulated ECs. Pre-incubation of the TNFalpha-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.
authors: Division of Medical Engineering Research, National Health Research Institutes, Taipei 114, Taiwan, ROC. jjchiu@nhri.org.tw
authors: Jeng-Jiann
authors: JJ
authors: Chiu
authors: Cheng-Nan
authors: CN
authors: Chen
authors: Pei-Ling
authors: PL
authors: Lee
authors: Cheng Tsair
authors: CT
authors: Yang
authors: Han Sheng
authors: HS
authors: Chuang
authors: Shu
authors: S
authors: Chien
authors: Shunichi
authors: S
authors: Usami
mesh_terms: D001783:Blood Flow Velocity; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D019040:E-Selectin; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods*; D018056:Hemorheology / Q000295:instrumentation / Q000379:methods; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D044085:Microfluidics / Q000295:instrumentation / Q000379:methods*; D009000:Monocytes / Q000166:cytology* / Q000502:physiology*; D012212:Rheology / Q000295:instrumentation / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D019040:E-Selectin; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1