[Glycocalyx is an active part of the endothelium]

The inner side of the endothelium is covered by a thin layer of glycosylated proteins called the glycocalyx, which binds plasma to its surface up to a total thickness of 1-3 µm. The glycocalyx governs the endothelial permeability for macromolecules and has a key role in the regulation of microvascular perfusion. The glycocalyx also prevents adhesion of thrombocytes to the endothelial surface and counteracts microthrombosis by harbouring antithrombin III and thrombomodulin in its plasma layer. Knowledge about the ultrastructure of the glycocalyx has resulted in a revision of the Starling equation, which currently takes little notice of the oncotic pressure of the interstitial fluid space. The glycocalyx is involved in the initiation of the inflammatory response and is easily broken down (shedded) in response to sepsis, trauma, surgery, and cardiovascular disease. A shedded glycocalyx layer seems to impair the prognosis of heart failure and  kidney disease.  Its role as a mediator of cardiovascular complications to chronic disease is currently an important research topic.