Effects of the Esl on Stresses Experienced by Endothelial Cells

INTRODUCTION A large body of experimental evidence shows that the endothelial surfaces of microvessels are lined with a relatively thick layer of macromolecules, which has a substantial impact on the mechanics and hemodynamics of blood flow [1]. This layer, known as the glycocalyx or endothelial surface layer (ESL), has been estimated to be from 0.3 μm to more than 1 μm thick. Its hemodynamic effects include a marked reduction in tube hematocrit below expected levels, due to the exclusion of red blood cells from a zone near the vessel wall [2], and a significant increase in flow resistance [3]. Information about the mechanical properties of the ESL has been deduced from observations of blood flow in microvessels [2-4]. However, the physiological role of the ESL is not well established. Here, we explore its potential role in modulating the forces experienced by endothelial cells and red blood cells (RBCs) when blood flows through capillaries. In particular, we examine the effect on the ESL on the transient stresses resulting from the particulate nature of blood and from the irregularity of capillary cross-sections.