Finite Platelet Size Could Be Responsible for Platelet Margination Effect

Abstract

Blood flows through vessels as a segregated suspension. Erythrocytes distribute closer to the vessel axis, whereas platelets accumulate near vessel walls. Directed platelet migration to the vessel walls promotes their hemostatic function. The mechanisms underlying this migration remain poorly understood, although various hypotheses have been proposed to explain this phenomenon (e.g., the available volume model and the drift-flux model). To study this issue, we constructed a mathematical model that predicts the platelet distribution profile across the flow in the presence of erythrocytes. This model considers platelet and erythrocyte dimensions and assumes an even platelet distribution between erythrocytes. The model predictions agree with available experimental data for near-wall layer margination using platelets and platelet-modeling particles and the lateral migration rate for these particles. Our analysis shows that the strong expulsion of the platelets from the core to the periphery of the blood vessel may mainly arise from the finite size of the platelets, which impedes their positioning in between the densely packed erythrocytes in the core. This result provides what we believe is a new insight into the rheological control of platelet hemostasis by erythrocytes.

Numerical investigation of the hemostasis process in transient blood flow

“…10 A lot of numerical models have been developed in the past decade in order to calculate the platelet concentration profi le. [11][12][13] Their main fi ndings are that the marginating property of platelets is mainly caused by the fi nite size effect of both the smaller platelets and the signifi cantly larger red blood cells (RBC). Technically the rolling motion of the larger RBCs pushes the platelets to the sides of the fl ow channel, thus creating a highly uneven platelet distribution across the diameter of the vessels.…”

Cross-Sectional Distributions of Platelet-Sized Particles in Blood Flow through Microchannels

“…Since this is evidently expedient in platelet functions of hemostasis, there have been intensive studies on the platelet behavior in microvessels, including in vivo and in vitro experiments and numerical model studies. [3][4][5][6][7][8] In general, the Reynolds numbers for the microcirculation are very small.…”

Numerical simulation of blood flow in large vessels during thrombus formation

“…11 A lot of numerical models have been developed in the past decade in order to calculate the platelet concentration profile. [12][13][14] Their main findings are that the margination effect of platelets is mainly caused by the finite size effect of both the smaller platelets and the significantly larger red blood cells (RBC). The rolling motion of the larger RBCs pushes the platelets to the sides of the flow channel.…”