Numerical simulations of deformation and aggregation of red blood cells in shear flow

Computing Sickle Erythrocyte Health Index on quantitative phase imaging and machine learning

Sickle cell disease (SCD) is a genetic disorder characterized by abnormal hemoglobin and deformation of red blood cells (RBCs), leading to complications and reduced life expectancy. This study developed an in vitro assessment, the Sickle Erythrocyte Health Index, using quantitative phase imaging (QPI) and machine learning to model the health of RBCs in people with SCD. The health index combines assessment of cell deformation, sickle-shaped classification, and membrane flexibility to evaluate erythrocyte health. Using QPI and image processing, the percentage of sickle-shaped cells and membrane flexibility were quantified. Statistically significant differences were observed between individuals with and without SCD, indicating the impact of underlying pathophysiology on erythrocyte health. Additionally, sodium metabisulfite led to an increase in sickle-shaped cells and a decrease in flexibility in the sickle cell blood samples. Based on these findings, two approaches were used to calculate the Sickle Erythrocyte Health Index: one using hand-crafted features and one using learned features from deep learning models. Both indices showed significant differences between non-SCD and SCD groups and sensitivity to changes induced by sodium metabisulfite. The Sickle Erythrocyte Health Index has important clinical implications for SCD management and could be used by providers when making treatment decisions. Further research is warranted to evaluate the clinical utility and applicability of the Sickle Erythrocyte Health Index in diverse patient populations.

Numerical Simulations of the Motion and Deformation of Three RBCs during Poiseuille Flow through a Constricted Vessel Using IB-LBM

The immersed boundary-lattice Boltzmann method (IB-LBM) was used to examine the motion and deformation of three elastic red blood cells (RBCs) during Poiseuille flow through constricted microchannels. The objective was to determine the effects of the degree of constriction and the Reynolds (Re) number of the flow on the physical characteristics of the RBCs. It was found that, with decreasing constriction ratio, the RBCs experienced greater forced deformation as they squeezed through the constriction area compared to at other parts of the microchannel. It was also observed that a longer time was required for the RBCs to squeeze through a narrower constriction. The RBCs subsequently regained a stable shape and gradually migrated toward the centerline of the flow beyond the constriction area. However, a sick RBC was observed to be incapable of passing through a constricted vessel with a constriction ratio ≤1/3 for Re numbers below 0.40.

3D NUMERICAL STUDY OF CELL DEFORMATION AND MIGRATION IN A FLOW CHAMBER

In recent years, the physiological phenomena of cell displacement and deformation in blood vessels have gradually become an important topic in the field of biomechanics, and also have important theoretical significance and application value in clinical medicine. To study the migration and deformation of blood cell, the influence of elastic modulus on its behavior, and the effect of deformation on its migration. A numerical simulation of a single cell displacement and deformation in a flow chamber was conducted in the present study using a computer program based on the fluid–solid coupling. The displacement and deformation of the cells with different elastic modulus as well as the influence of deformation on the movement of the cell were investigated. The results showed that the cell with greater elastic modulus had a smaller deformation in the direction of gravity and fluid velocity. The deformation of the cell had obvious effect on the displacement in the direction of gravity. The smaller the deformation of the cell in the direction of gravity was, the higher the cell could jump. The three-dimensional numerical calculation method adopted in this paper and the results obtained can provide a reference for the study of the cell mechanic behavior in the vessels.