Comparing diabetic versus healthy red blood cell partitioning at vascular bifurcations

As red blood cells (RBCs) flow through a capillary vessel bifurcation, they usually do not distribute (i.e. partition) in the downstream branches in proportion to the flow rates. Often, the branch with the higher flow fraction receives a disproportionately higher fraction of cells. Partitioning is the key mechanism of RBC distribution in microcirculation. Since RBCs are extremely deformable and their size is comparable to the diameter of a capillary vessel, such partitioning is expected to depend on the degree of deformation that each cell undergoes as it flows through a bifurcation. The deformability, shape and size of RBCs change in diabetes. Nearly no study exists comparing the partitioning behavior of diabetes versus healthy cells. In this work, a high-fidelity computational model is used to accurately resolve cellular scale hemodynamics. This allows for a direct comparison between flows of healthy and diabetic RBCs through vessels of varying diameter, hematocrit, and average plasma flow partitioning. Significant differences include situations where diabetic cells exhibit no partitioning at all while healthy cells do. This finding has physiological significance as it implies that diabetic RBCs are more heterogeneously distributed in the microcirculation than healthy cells. The effect of cell biases from downstream bifurcations, interactions with leukocytes, and influence of diabetic cells on the cell free layer are also observed.