Antimargination of microparticles and platelets in the vicinity of branching vessels.
We investigate the margination of microparticles/platelets in blood flow through complex geometries typical for in vivo vessel networks: a vessel confluence and a bifurcation. Using 3D Lattice-Boltzmann simulations, we find that behind the confluence of two vessels a cell-free layer devoid of red blood cells develops in the channel center. Despite its small size of roughly one micrometer, this central cell-free layer persists for up to 100 $\mu$m after the confluence. Most importantly, we show that this layer also contains a significant amount of microparticles/platelets. At bifurcations, however, a similar effect does not appear and margination is largely unaffected by the geometry. This anti-margination towards the vessel center after a confluence may explain in-vivo observations where platelet concentrations near the vessel wall are seen to be much higher on the arteriolar side (containing bifurcations) than on the venular side (containing confluences) of the vascular system.
Publisher URL: http://arxiv.org/abs/1801.08708