Vascular bed origin dictates flow pattern regulation of endothelial adhesion molecule expression

Area of Science:

• Vascular Biology and Endothelial Cell Function
• Immunology and Inflammation
• Biophysics and Hemodynamics

Background:

• Endothelial cell phenotypes vary by function and vascular origin, influencing disease susceptibility.
• Leukocyte adhesion to activated endothelium is a critical early step in numerous diseases.
• Understanding how vascular bed-specific flow patterns affect endothelial cells is crucial for disease research.

Purpose of the Study:

• To compare the influence of vascular bed-specific flow patterns on adhesion molecule expression in human saphenous vein endothelial cells (HSVEC) and coronary artery endothelial cells (HCAEC).
• To investigate the differential effects of venous and coronary artery flow on endothelial cell responses to inflammatory stimuli.
• To explore the role of Kruppel-like factors (KLFs) in flow-mediated regulation of endothelial adhesion molecules.

Main Methods:

• In vitro study comparing immune cell attachment to TNF-alpha-stimulated HSVEC and HCAEC under physiological venous and coronary artery flow conditions.
• Measurement of soluble adhesion molecules (E-selectin, VCAM-1, ICAM-1) in cell supernatants.
• Analysis of endothelial adhesion molecule and transcription factor (KLF2, KLF4) expression using flow cytometry and Western blotting.

Main Results:

• Immune cell attachment increased significantly when HSVEC were exposed to coronary artery flow compared to venous flow or HCAEC under coronary flow.
• HSVEC exposed to coronary artery flow exhibited higher soluble E-selectin, VCAM-1, and ICAM-1 levels.
• Flow patterns differentially modulated adhesion molecule expression; coronary flow increased VCAM-1 in HSVEC but attenuated it in HCAEC, while ICAM-1 was induced in both under specific conditions. KLF4 overexpression reduced E-selectin and VCAM-1 expression statically. Both flow patterns induced KLF2 and KLF4 expression in both cell types.

Conclusions:

• Vascular bed of origin significantly dictates endothelial cell responses to flow patterns, affecting adhesion molecule expression and immune cell adhesion.
• Differential expression of adhesion molecules between HSVEC and HCAEC under varying flow conditions may contribute to distinct pathological susceptibilities.
• Flow-dependent and independent pathways, involving transcription factors like KLFs, play complex roles in regulating endothelial ICAM-1 expression with marked dissimilarities between endothelial cell types.