SERPINE1 and endothelial dysfunction: In addition, elevated plasma PAI-1 levels are associated with vascular thrombosis.12 A previous study suggested that high levels of PAI-1 in CAD are associated with the risk of endothelial dysfunction and premature atherosclerosis.13 Sialic acid (SA) is derivative of neuraminic acid, and comprises the terminal sugar part of the oligosaccharide chain in glycolipids and glycoproteins, acting as a cofactor in several cell surface receptors, such as LDL receptor.