Comparative Analysis of the Endothelial Glycocalyx in Aortic Valve and Vascular Endothelial Cells Under Distinct Shear Stress Conditions

Abstract

Background:  The endothelial glycocalyx (EG) regulates vascular permeability, inflammation, and mechanotransduction. While the EG has been studied in vascular endothelial cells (VECs), less is known about its behavior in aortic valve endothelial cells (AVECs), which experience distinct mechanical forces. Characterizing EG differences could inform valve disease models and tissue engineering strategies.

Objective:  We aimed to characterize structural and functional differences in the EG of AVECs and VECs subjected to varying shear stress conditions.

Methods:  Primary AVECs and VECs were exposed to steady laminar flow (S-flow, 20 dynes/cm²), disturbed flow (D-flow, 5 dynes/cm²), and low-magnitude S-flow (5 dynes/cm²) using a cone-and-plate system. Glycocalyx structure was assessed by wheat germ agglutinin (WGA) staining. Gene expression of core EG component (SDC1) and the inflammatory marker VCAM-1 was quantified by RT-qPCR.

Results: Preliminary findings show that under high S-flow, AVECs downregulate the GAG chain-synthesizing enzymes EXT-1 and CHSY-1 relative to static controls, a response not seen in VECs. Under D-flow, SDC1 expression differed between AVECs and VECs. In VECs, low S-flow (5 dynes/cm²) reduced WGA staining intensity and upregulated VCAM-1, consistent with a pro-inflammatory, glycocalyx-shedding phenotype. In contrast, low S-flow had minimal impact on VCAM-1 expression in AVECs.

Conclusions: These findings suggest intrinsic differences in EG synthesis, structure, and mechanotransduction between aortic valve and vascular endothelial cells. Understanding these differences is crucial for advancing models of valve-specific endothelial biology and informing tissue-engineered valve design strategies.