Effect of fluid viscosity and erythrocytes on monocyte adhesion

Monocyte recruitment to vascular endothelium is a key event linked to the development of atherosclerosis. Adhesion is influenced by many parameters including local fluid dynamics, intracellular collisions, and adhesion receptor expression. Elevated medium viscosity as well as the presence of erythrocytes in monocyte-containing media was found to increase monocyte adhesion to vascular endothelial cells. By comparing monocyte rolling velocities and arrest durations in fluids of differing viscosities at the same shear rates, monocyte adhesion was found to be shear stress dependent. Supplementation of the monocyte-containing medium with red blood cells increased tethering frequencies to a greater extent than the effect of elevated viscosity alone.