Functional and morphological approach to the endothelial glycocalyx in mice carotid and mesenteric arteries

Abstract

The endothelial glycocalyx (EG), a complex hair-like structure attached to the surface of the endothelium, is primarily composed of proteoglycans and glycosaminoglycans. Positioned to sense shear stress caused by blood flow, the EG transforms these mechanical forces into biochemical responses through a mechanism known as mechanotransduction. This study, utilizing pressure myography, focuses on the key role of the endothelial EG in endothelial functions, particularly in mechanotransduction. We explored two endothelium-dependent signaling pathways activated in the presence of shear stress or vasodilators, i.e. the nitric oxide (NO) and endothelium-derived hyperpolarization (EDH) pathways. Visualization of the EG was performed by confocal microscopy, after immunolabeling of sialic acid and n-acetylglucosamine residues using fluorescent wheat germ agglutinin (WGA). This approach also allowed the quantification of EG degradation after sheddases treatments. The results confirm a more pronounced contribution of the NO pathway to ACh-induced vasodilation in carotid arteries, while the EDH pathway predominates in mesenteric arteries. Conversely, when it comes to flow-mediated dilation, the EDH pathway prevails in both carotid and mesenteric arteries. Furthermore, the degradation of the EG in mouse mesenteric arteries, by sheddases induces strong and significant decreases in EDH-dependent vascular responses, underscoring the crucial role of the EG in regulating endothelial function.

Date of Award	15 Jan 2024
Original language	English
Awarding Institution	University of Namur
Supervisor	Nathalie Kirschvink (Supervisor) & Sophie Dogne (Co-Supervisor)