Leukocyte margination at arteriole shear rate

Abstract

We numerically investigated margination of leukocytes at arteriole shear rate in straight circular channels with diameters ranging from 10 to 22 μm. Our results demonstrated that passing motion of RBCs effectively induces leukocyte margination not only in small channels but also in large channels. A longer time is needed for margination to occur in a larger channel, but once a leukocyte has marginated, passing motion of RBCs occurs continuously independent of the channel diameter, and leukocyte margination is sustained for a long duration. We also show that leukocytes rarely approach the wall surface to within a microvillus length at arteriole shear rate.

Hemodynamics in the Microcirculation and in Microfluidics

“…Such qualitative differences in large deformation yield quantitative differences in material property estimations. For example, Dao et al 27 and Takeishi et al 140 numerically estimated the shear elastic modulus G s of the RBC membrane, using the Mooney-Rivlin law and the Skalak law, respectively. In both studies, G s was determined by comparing the results of an experimental optical tweezer stretching test.…”

“…A lattice-Boltzmann method (LBM) is also widely used for cellular flow. 122,138,140 This method is fully explicit and no iterative solver is needed in the solving procedure. LBM can explicitly treat the inertia effect, unlike BEM, but the numerical accuracy using LBM becomes less than that with BEM, because LBM is often coupled with an immersed boundary method for tracking the interface, and physical quantities at the membrane, such as velocity and body force, are calculated using an interpolation function.…”

“…Due to the heavy computational load required when solving the hydrodynamic interactions between a leukocyte and many RBCs, 3D simulations have not been reported until recently. 41,140 To accelerate 3D simulation, graphics processing unit (GPU) computing was used effectively by Takeishi et al 140 They showed that margination occurs, even for arteriole shear rates; however, the separation distance between the leukocyte and the wall surfaces may not be small enough for tethering with arteriole shear rates.…”

“…The presence of RBCs, in addition, affects the dynamics of leukocytes, as indicated by studies on leukocyte margination. 41,140 To fully understand adhesive phenomena of leukocytes, more experimental data on adhesive dynamics at the cellular scale are needed.…”

Flow structures and red blood cell dynamics in arteriole of dilated or constricted cross section

“…It has been suggested in Omori (2015) that the apparent viscosity and the cell-free layer thickness may be primarily determined by macroscopic parameter, such as vessel diameter, flow rate, and hematocrit, rather than by precise microscopic cellular mechanics, such as the membrane mechanics and fluid motion around the cell. Despite this, it is observed that high RBC concentration and inter-cellular fluid mechanics interactions are responsible for the outward radial migration of white blood cells (Takeishi (2014)) and platelets, with evident physiological relevance. Experimental studies have also outlined blood mass transport mechanisms under both physiological and pathological conditions (Lima (2008)).…”