Abstract 312: Diosmin Enhances Endothelial Glycocalyx Integrity And Reverses Endothelial Dysfunction In Injured Blood Vessels

Objective: This study determined if diosmin, a flavone glycoside of diosmetin, can repair damaged extracellular endothelial glycocalyx (GCX) (readouts: GCX labels including wheat germ agglutinin (WGA), hyaluronic acid (HA) binding protein, and core protein syndecan-1 (SDC1) antibody). Additionally, the study wanted to identify if diosmin can reverse endothelial dysfunction by improving vascular tone (readouts: endothelial nitric oxide synthase expression (eNOS), vessel wall thickness, and vessel lumen diameter) and vascular permeability (readouts: inflammatory cell uptake). Methods: In a mouse, acute disturbed blood flow pattern was induced by ligating three of the four left carotid artery (LCA) branches. This partial LCA ligation mouse model has shown to induce rapid endothelial dysfunction and loss of endothelial GCX. The right carotid artery (RCA) was the designated control for each mouse, as no surgical intervention occurred. Diosmin (50 mg/kg) was administered daily either orally or intraperitoneally for 7 days, 72 hours after the ligation surgery. One week after the first treatment dose, mice were sacrificed via exsanguination, and tissue was collected and fixed for further processing. Results: Diosmin enhanced endothelial GCX coverage and thickness after one week of treatment, as demonstrated by increased fluorescence of WGA, HA binding protein, and SDC1 antibody label on the diosmin-treated ligated LCA wall, compared to untreated tissue. Furthermore, diosmin also appeared to improve vascular tone as demonstrated by the increase in percent of total eNOS that is activated (p-eNOS/total eNOS) in diosmin-treated ligated LCA, compared to the untreated LCA. Interestingly, diosmin had limited effect on vessel wall thickness and vessel diameter. Finally, diosmin demonstrated attenuation of vessel inflammation by impeding macrophage (CD68 + ) uptake within ligated LCA walls. Conclusion: The novelty of our findings is that diosmin enhances endothelial GCX integrity. This study also demonstrated that diosmin can improve endothelium functionality after injury by decreasing inflammation and improving vascular tone. This work can lead to a new option for endothelial GCX restoration and endothelial-dependent aspects of vascular disease.