PROTEOGLYCANS Proteoglycans are proteins that make up endothelial glycocalyx which is the backbone of endothelial glycocalyx and bind one or more GAGs. Glycosaminoglycans that are bound to proteoglycans vary and can change depending on the stimulus given by substances contained in the plasma. 2,5, 6 Proteoglycans are composed by core proteins which consist of syndecan, which attach to the endothelial through the membrane-spanning, while glypican attaches to the surface of the vascular

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... l through the GPI anchor. Perlecan, versican, biglycan, decorin, and mimecan are proteoglycans which after being formed and undergo modification in the GAG, the blood vessel lumen will be secreted. Each proteoglycan molecule can bind GAG that is different depending on the stimulus received by cells. 2,5,6 Syndecan is the most glycoprotein composed of endothelial glycocalyx with molecular weights ranging between 19-35 kDa. Research on the umbilical vein endothelial found that syndecan-1 was expressed the most, followed by syndecan-2, syndecan-3, syndecan-4, and glypican-1. 7 Glycosaminoglycans are bound to the sides of the core protein consisting of heparan sulfate (HS), chondroitin sulfate, dermatan sulfate, hyaluronan, and keratan sulfate. Heparan sulfate is the highest GAG in endothelial glycocalyx, ranges from 50 to 90%, and has a ratio of 4:1 to chondroitin sulfate, the second largest GAG. 8 1 ABSTRACT The surface of endothelial cells is filled with various membrane-bound molecules that form the glycocalyx. The endothelial glycocalyx is a surface layer mainly consisted of glycosaminoglycans that include heparan sulfate, chondroitin sulfate, and hyaluronic acid and its core proteins. Previous studies suggest that endothelial surface glycocalyx shedding could play a role in endothelial dysfunction and inflammation. This article will review the endothelial glycocalyx and its role in sepsis.