Abstract
The endothelial lining of blood vessels presents a large surface area for
exchanging materials between blood and tissues. The endothelial surface layer
(ESL) plays a critical role in regulating vascular permeability, hindering
leukocyte adhesion as well as inhibiting coagulation during inflammation.
Changes in the ESL structure are believed to cause vascular hyperpermeability
and induce thrombus formation during sepsis. In addition, ESL topography is
relevant for the interactions between red blood cells (RBCs) and the vessel
wall, including the wall-induced migration of RBCs and formation of a cell-free
layer. To investigate the influence of the ESL on the motion of RBCs, we
construct two models to represent the ESL using the immersed boundary method.
In particular, we use simulations to study how lift force and drag force change
over time when a RBC is placed close to the ESL as the thickness, roughness,
and permeability of the ESL vary. We find that roughness has a significant
effect on the wall-induced migration of the RBC when the ESL is highly
permeable and that the wall-induced migration can be significantly inhibited by
the presence of a thick ESL.