From Experiments to Simulation: Shear-Induced Responses of Red Blood Cells to Different Oxygen Saturation Levels

Figures

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  FIGURE 1. Pulsatile flow profile used as an inlet boundary condition of the carotid artery model. The pulse has a period of 0.5 s and a frequency of 120 beats per minute.

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  FIGURE 2. RBC deformability curves obtained by the change in elongation index (EI) versus shear stress (SS). Each circle represents an EI value corresponding to a different SS level (0.3, 0.53, 0.94, 1.65, 2.91, 5.15, 9.09, 16.04, 28.32, and 50 Pa). Data is collected from 10 different subjects with two replicative measurements and presented as mean ± standard error (SE). (A) The change in EI before and after 5 Pa SS in oxygenated conditions, (B) The change in EI before and after 5 Pa SS in deoxygenated conditions, (C) EI difference between oxygenation and deoxygenation before 5 Pa SS, (D) EI difference between oxygenation and deoxygenation after 5 Pa SS. ****p < 0.0001, ∗∗∗p < 0.001, ∗∗p < 0.01, ∗p < 0.05.

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  FIGURE 3. Maximal elongation and half shear stress parameters. Data is collected from 10 different subjects with two replicative measurements and presented as mean ± standard deviation (SD). SS1/2 (A), EImax (B), SS1/2/EImax (C) parameters in oxygenated and deoxygenated conditions before and after 5 Pa SS application. ∗p < 0.05 (The difference between before and after SS), δp < 0.001 (The difference in SS1/2 values between oxygenated and deoxygenated conditions), εp < 0.0001 (The difference in SS1/2/EImax values between oxygenated and deoxygenated conditions before SS).

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  FIGURE 4. Correlation between elongation index (EI) and shear stress (SS). EI-SS correlation for oxygenated blood samples with a 2-element exponential fit, for which R2 is 0.9952 (p < 0.05) (A) and for deoxygenated blood samples with a 2-element exponential fit, for which R2 is 0.9940 (p < 0.05) (B).

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  FIGURE 5. Velocity distribution at a cross section close to the bifurcation region is presented here: the location of the velocity magnitude contours (A), vorticity streamlines (B), and cross-sectional plane (C).

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  FIGURE 6. Velocity distribution color-coded by velocity magnitude. Contours are shown in the two-dimensional midplane in the axial direction (A). Velocity vector distribution in the three-dimensional artery geometry. The vectors are colored by the velocity magnitude and the vector size is scaled based on the velocity magnitude (B). Velocity streamlines are presented inside the 3D domain and colored by velocity magnitude (C).

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  FIGURE 7. Pressure and wall shear stress. Pressure distribution (A) and wall shear stress (WSS) (B) on the carotid artery wall.

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  FIGURE 8. Viscosity distribution on the two-dimensional midplane in the axial direction. (A) shows the range with minimum and maximum viscosity values while (B) shows the scaled-down range of the viscosity for detailed visualization.

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  FIGURE 9. Elongation index distribution for blood flow simulation. Contours are shown on the two-dimensional midplane in the axial direction. (A) shows the range with minimum and maximum EI values while (B) shows the scaled-down range of EI values for detailed visualization for oxygenated blood. (C) shows the range with minimum and maximum EI values while (D) shows the scaled-down range of EI values for detailed visualization for deoxygenated blood.

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  FIGURE 10. The associations between hemoglobin (Hb) and RBC membrane proteins. (A) shows Hb carrying oxygen and no interaction with membrane proteins in oxygenated state. (B) shows the association of Hb with membrane proteins while carrying no oxygen in deoxygenated state.