Heparin Impairs Glycocalyx Barrier Properties and Attenuates Shear Dependent Vasodilation in Mice

Abstract

The endothelial glycocalyx is a hydrated mesh of polysaccharides and adsorbed plasma proteins that forms the true interface between the flowing blood and the endothelium. We hypothesized in the present study that competitive binding of heparin to glycocalyx-associated proteins would affect glycocalyx barrier properties and mechanotransduction of shear stress to the endothelium. In anesthetized mice, the clearance of 70-kDa dextrans from the circulation was increased ( P P P =0.008) in t ₅₀ of diameter recovery, and this effect was associated with a diminished NO bioavailability. Infusion of hyaluronidase resulted in reductions ( P 50 of diameter recovery was not affected. In conclusion, our data in mice show that a heparin challenge is associated with increased vascular leakage of dextrans and impaired arteriolar vasodilation during reactive hyperemia. Our data suggest that protein–heparan sulfate interactions are important for a functional glycocalyx.