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Cardiovascular Engineering

Cardiovascular Engineering - Poster Session C

Poster H11 - Evaluating the impact of Shear Stress on the eGCX and its Influence on Vascular Health

Friday, October 25, 2024
10:00 AM - 11:00 AM EST
Location: Exhibit Hall E, F & G

Introduction:  The Endothelial Glycocalyx (eGCX) is a fascinating and crucial part of vascular health and function. It acts as a protective barrier for endothelial cells as well as a shear stress mechanosensor. The eGCX is comprised of a variety of membrane-bound macromolecules, the most common being glycoproteins, proteoglycans, and glycosaminoglycans. Shear stress caused by both laminar and oscillatory blood flow can affect the eGCX structure, interfere with cell signaling, cause endothelial cell inflammation, and eventually lead to the onset of atherosclerosis. A healthy eGCX encourages blood flow by repelling the blood cells away from the endothelial cells in addition to signaling for eNOS production. Without eNOS production, plaque buildup and inflammation quickly start to develop within one of the body's most vital organs.

Materials and

Methods:  In this study, we assessed the level of eGCX expression in Human Umbilical Vein Endothelial Cells (HUVECs) that were cultured in a 60mm plate for 7 days to allow for eGCX growth. After culturing the cells, we used a cone and plate bioreactor system to expose the HUVECs to shear stresses at 6 dyne/cm² and 20 dyne/cm² for 24 hours to mimic the pathological and physiological vascular blood flow. The 6-dyne group was used to represent the non-uniform laminar blood flow, as found in the bifurcated regions of the arteries. The 20-dyne group was used to represent the standard laminar blood flow. After shear stress testing, the amount of eGCX expressed was measured through PCR and Wheat Germ Agglutinin (WGA) staining. Expression levels of genes such as syndecan, glypican, MMP-2, eNOS, and CD36 allow for the assessment of the eGCX health and endothelial cell function. Markers for endMT and inflammation, such as CCL-2 and SNAIL-1, were also tested to show potential activation of atherosclerosis. WGA staining was used to visualize eGCX around the cells. A static control was used to show eGCX behavior without exposure to shear stress.

Results, Conclusions, and Discussions: Preliminary results show that the WGA stain was successful in staining the eGCX and can be used as a visual comparison tool for different shear exposure groups. Lower levels of shear stress have yielded a decrease in visual eGCX using WGA staining, while cells exposed to higher levels of shear stress have a greater eGCX visibility. We hypothesize that the eGCX expression will increase when the HUVECs are exposed to higher levels of shear stress and decrease when exposed to lower shear stress. Previous literature has shown that exposing Human Aortic Endothelial Cells (HAECs) to high levels of shear stress shows a greater amount of eGCX visible when staining and an enhancement of gene expression for eGCX growth and function such as eNOS. Additionally, literature has shown that a higher expression of genes related to endMT and inflammation is far more prevalent in lower shear stress levels than in higher levels of shear stress. Understanding how the endothelial glycocalyx changes in different areas of the heart is critical for understanding what causes endMT and atherosclerosis. This research is the first step to finding a solution. The implications of our findings on endothelial cell health and atherosclerosis are significant, potentially leading to new avenues for treatment and prevention.

Acknowledgements (Optional):  Funding from the American Heart Association Summer Research Program 24IAUST1247747

Thank you to George Ezeokeke for his mentorship