Computational investigation of flow dynamics and mechanical retention of age-associated red blood cells in the spleen

Red blood cells (RBCs) change shape and deformability with age, making them more likely to be trapped in the splenic slits (IESs) and removed from circulation. Existing evidence suggests that cell size and viscoelastic properties are altered during aging, making it challenging to identify the determinants of mechanical retention of aged RBCs in the spleen. Herein, we present a comprehensive computational study to investigate the flow dynamics, morphological changes, and mechanical retention of age-associated RBCs in the splenic IESs. Our results show that, before reaching the critical size for the age-associated RBC to be trapped in the IESs, the reduced size of the RBC can shorten the transit time it takes to pass through the IESs, while the increased membrane viscosity slows it down. A narrower IES requires the RBC to undergo greater deformation to pass through. Furthermore, during the shrinkage associated with normal aging, a more significant critical pressure gradient is required for RBCs to deform more to pass through the IESs, resulting in more intense damage. These quantitative findings provide unique insights into the traversal dynamics and retention mechanism of age-associated RBCs.

Automated summary

Red blood cells (RBCs) change shape and deformability with age, making them more likely to be trapped in the splenic slits (IESs) and removed from circulation. Existing evidence suggests that cell size and viscoelastic properties are altered during aging, making it challenging to identify the determinants of mechanical retention of aged RBCs in the spleen.