Endothelial glycocalyx: permeability barrier and mechanosensor

Area of Science:

• Biomedical Engineering
• Cell Biology
• Physiology

Background:

• Endothelial cells possess a thick, polysaccharide-rich layer influencing molecular transport.
• The mechanical properties of this layer restrict plasma component access to cell membranes.

Purpose of the Study:

• To compare the mechanosensor and permeability properties of the entire endothelial surface layer with its inner glycocalyx structures.
• To elucidate the role of the endothelial surface layer in transvascular exchange and vascular permeability.

Main Methods:

• Analysis of tracer penetration rates into the endothelial surface layer.
• Assessment of red and white blood cell movement mechanics in capillary microvessels.
• Comparative analysis of the whole endothelial surface layer versus its inner quasi-periodic structure.

Main Results:

• The inner glycocalyx layer (100-150 nm) exhibits distinct mechanosensor and permeability properties compared to the whole endothelial surface layer.
• Barrier properties of the entire layer do not fully represent the primary molecular filter responsible for transvascular exchange.
• Differences are attributed to dynamic processes like tracer binding, component turnover, and signaling pathway activation.

Conclusions:

• The inner glycocalyx structure is critical for determining transvascular exchange and vascular permeability.
• Dynamic aspects of the endothelial surface layer significantly influence its overall barrier function.
• Understanding these dynamics is key to comprehending endothelial cell function and vascular health.