Hemodynamic-force-induced difference of interendothelial junctional complexes

Area of Science:

• Cardiovascular Biology
• Endothelial Cell Biology
• Atherosclerosis Research

Background:

• Endothelial cells lining blood vessels are exposed to varying shear stress levels.
• Regions of high and low shear stress in the aorta exhibit distinct endothelial cell properties.
• Understanding these differences is crucial for elucidating mechanisms of atherosclerosis.

Purpose of the Study:

• To investigate the relationship between shear stress, endothelial cell permeability, and lipid deposition in the rabbit aorta.
• To characterize the structural differences in endothelial cell junctions under varying shear stress conditions.

Main Methods:

• Utilized normolipidemic and atherogenic diet-fed rabbits.
• Employed freeze fracture electron microscopy to study endothelial cell tight junctions.
• Used cultured porcine aortic endothelial cells subjected to controlled shear stress in a flow chamber.

Main Results:

• Low shear stress regions showed higher endothelial cell permeability and were prone to lipid deposition during atherogenic diet feeding.
• High shear stress regions exhibited zonular type tight junctions, while low shear regions had more macular junctions.
• Exposure to shear stress in vitro induced protein particle ridges at endothelial cell-cell contacts, with increased shear enhancing junctional protein expression.

Conclusions:

• Endothelial cell permeability and tight junction structure are influenced by regional shear stress in the aorta.
• High shear stress regions are protected from lipid deposition due to specific junctional adaptations.
• Shear stress plays a critical role in maintaining endothelial barrier integrity and preventing atherogenesis.