Hydrodynamic Interaction Between a Platelet and an Erythrocyte: Effect of Erythrocyte Deformability, Dynamics, and Wall Proximity

Abstract

We present three-dimensional numerical simulations of hydrodynamic interaction between a red blood cell (RBC) and a platelet in a wall-bounded shear flow. The dynamics and large deformation of the RBC are fully resolved in the simulations using a fronttracking method. The objective is to quantify the influence of tank treading and tumbling dynamics of the RBC, and the presence of a bounding wall on the deflection of platelet trajectories. We observe two types of interaction: A crossing event in which the platelet comes in close proximity to the RBC, rolls over it, and continues to move in the same direction; and a turning event in which the platelet turns away before coming close to the RBC. The crossing events occur when the initial lateral separation between the cells is above a critical separation, and the turning events occur when it is below the critical separation. The critical lateral separation is found to be higher during the tumbling motion than that during the tank treading. When the RBC is flowing closer to the wall than the platelet, the critical separation increases by several fold, implying the turning events have higher probability to occur than the crossing events. On the contrary, if the platelet is flowing closer to the wall than the RBC, the critical separation decreases by several folds, implying the crossing events are likely to occur. Based on the numerical results, we propose a mechanism of continual platelet drift from the RBC-rich region of the vessel towards the wall by a succession of turning and crossing events. The trajectory deflection in the crossing events is found to depend nonmonotonically on the initial lateral separation, unlike the monotonic trend observed in tracer particle deflection and in deformable sphere-sphere collision. This nonmonotonic trend is shown to be a consequence of the deformation of the RBC caused by the platelet upon collision. An estimation of the platelet diffusion coefficient yields values that are similar to those reported in experiments and computer simulations with multicellular suspension.

Compression force sensing regulates integrin αIIbβ3 adhesive function on diabetic platelets

“…4b ), demonstrating a critical role for RBCs in promoting the diabetic hyperadhesive phenotype. RBCs have a well-defined role in enhancing platelet transport to the vessel wall (margination) 42 , 43 and recent rheological and modeling studies demonstrated that RBCs push and subject platelets to collision forces (compression) 44 , 45 , although how compression forces influence platelet adhesive function remains largely unknown. To address this, we developed a novel compression assay using a biomembrane force probe (BFP).…”

Systems Analysis of Thrombus Formation

“…4,72–75 Modeling blood as a continuum fluid is far more computationally efficient for calculation of complex velocity fields in vessels and does not require detailed descriptions of single cell dynamics. For simulations of thrombosis that involve single platelets depositing to a growing thrombus under flow conditions, the blood is still often treated as a continuum fluid, however the near wall excess concentration of platelets must be calculated or imposed as a way of accounting for the suspension nature of flowing blood.…”

The Effect of Hematocrit on Platelet Adhesion: Experiments and Simulations

“…In looking to explain the relationship between RBC hematocrit and bleeding, previous researchers have established that the distribution of platelets in arteries and arterioles (and microchannels of similar dimensions) is not uniform-platelets predominantly reside near the channel walls while RBCs occupy most of the volume close to the center in vitro (3)(4)(5)(6)(7), in silico (8)(9)(10)(11)(12)(13)(14)(15)(16)(17), and in vivo (18,19).…”