The luminal surface of endothelial cells within arteries, veins and microvessels is coated with a thin (~ 500 nm) glycocalyx layer of plasma proteins, sulfated proteoglycans, glycoproteins and hyaluronan (reviewed in Weinbaum) [10]. Endothelial cell glycocalyx has several recognized functions, including maintaining vascular integrity, permeability, shear stress, mechanosensing and inflammatory responses. Leukocytes traversing a small-caliber capillary actually crush the glycocalyx. The transient deformation quickly corrects due to the elasticity of core proteins that behave like elastic fibers [11].