The Structure and Function of the Glycocalyx and Its Connection With Blood-Brain Barrier

Abstract

The vascular endothelial glycocalyx is a dense, bush-like structure that is synthesized and secreted by endothelial cells and evenly distributed on the surface of vascular endothelial cells. The blood-brain barrier (BBB) is mainly composed of pericytes endothelial cells, glycocalyx, basement membranes, and astrocytes. The glycocalyx in the BBB plays an indispensable role in many important physiological functions, including vascular permeability, inflammation, blood coagulation, and the synthesis of nitric oxide. Damage to the fragile glycocalyx can lead to increased permeability of the BBB, tissue edema, glial cell activation, up-regulation of inflammatory chemokines expression, and ultimately brain tissue damage, leading to increased mortality. This article reviews the important role that glycocalyx plays in the physiological function of the BBB. The review may provide some basis for the research direction of neurological diseases and a theoretical basis for the diagnosis and treatment of neurological diseases.

The blood-brain barrier in aging and neurodegeneration

“…Complex tight junctions between the brain endothelial cells seal the paracellular space forming a continuous barrier, while the astrocytes, pericytes, and basement membrane surround the endothelial cells [ 3 ]. The endothelial cells are coated in glycocalyx on the luminal side and surrounded in the basement membrane on the abluminal side [ 4 ]. The basement membrane is composed of both an inner vascular basement membrane, which is secreted by endothelial cells and pericytes and an outer parenchymal basement membrane, which is secreted by astrocytes [ 1 ].…”

Vascular Endothelial Glycocalyx Damage and Potential Targeted Therapy in COVID-19

“…As is shown in Figure 1 , EGL is a glycoprotein network comprising membrane-binding proteoglycans with glycosaminoglycan side chains, glycoproteins bearing acidic oligosaccharides and terminal sialic acids, and plasma proteins (such as albumin and antithrombin) [ 37 , 38 ]. The syndecan and glypican families are the major proteoglycans tightly bound to the EC membrane [ 39 , 40 ]. There are five main components of glycosaminoglycan (GAG) side chains: heparan sulphate (HS), chondroitin sulphate (CS), dermatan sulphate (DS), keratan sulphate (KS), and hyaluronan (HA).…”

Vascularizing the brain in vitro

“…The luminal side of the BBB is covered by a thin and dense layer of a villiform substance secreted and synthesized by ECs, which is termed glycocalyx (GCX) ( Jin et al., 2021 ; Kutuzov et al., 2018 ). It is composed of proteoglycan polymers and glycosaminoglycan chains, including heparan sulfate, chondroitin sulfate, and hyaluronan ( Jin et al., 2021 ).…”

“…The luminal side of the BBB is covered by a thin and dense layer of a villiform substance secreted and synthesized by ECs, which is termed glycocalyx (GCX) ( Jin et al., 2021 ; Kutuzov et al., 2018 ). It is composed of proteoglycan polymers and glycosaminoglycan chains, including heparan sulfate, chondroitin sulfate, and hyaluronan ( Jin et al., 2021 ). Recent studies proved the importance of the presence of this substrate since it has a vital role in preventing coagulation and regulating the BBB permeability and the occurrence and development of inflammation ( Ando et al., 2018 ; Santa-Maria et al., 2019 ; Zhu et al., 2018 , 2021a ).…”