Effect of endothelial glycocalyx on water and low density lipoprotein (LDL) transport through the rat abdominal aorta

Am J Physiol Heart Circ Physiol. 2021 Mar 12. doi: 10.1152/ajpheart.00861.2020. Online ahead of print.ABSTRACTThe surface of vascular endothelial cells (ECs) is covered by a protective negatively charged layer known as the endothelial glycocalyx. Herein, we hypothesized its transport barrier and mechanosensory role in transmural water flux and low density lipoprotein (LDL) transport in an isolated rat abdominal aorta perfused under 85 mm Hg and 20 dyn/cm2 ex vivo. The endothelial glycocalyx was digested by hyaluronidase (HAase) from bovine tests. Water infiltration velocity (Vw) was measured by a graduated pipette. LDL coverage and mean maximum infiltration distance (MMID) in the vessel wall was quantified by confocal laser scanning microscopy. EC apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) technique, and leaky junction rates were evaluated by electron microscopy. The results showed a 42% degradation of the endothelial glycocalyx by HAase treatment increased VW, LDL coverage and MMID. Shear stress increased VW, which cannot be inhibited by HAase treatment. 4 h-shear application increased about 4 folds of LDL coverage, while exerted no significant effects on its MMID, EC apoptosis and the leaky junctions. On the contrary, 24-h shear exposure has no significant effects on LDL coverage, while increased 2.74 folds of MMID and about 53% of EC apoptotic rates that could be inhibited by HAase treatment. These results suggest e...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Source Type: research