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3819 Mechanisms of Red Blood Cell Splenic Filtration Revealed By Multiscale Modeling and in-Vitro Microfluidic Experiments

Program: Oral and Poster Abstracts
Session: 101. Red Cells and Erythropoiesis, Excluding Iron: Poster III
Hematology Disease Topics & Pathways:
Research, Fundamental Science, computational biology, Technology and Procedures
Monday, December 11, 2023, 6:00 PM-8:00 PM

Zhangli Peng, PhD1, Alexis Moreau2*, François Yaya3*, Huije Lu4*, Anagha Surendranath3*, Anne Charrier3*, Benoit Dehapiot3*, Emmanuelle Helfer3* and Annie Viallat3*

1Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL
2Yale University, New Haven, CT
3Aix Marseille Université, Marseille, France
4University of Illinois Chicago, Chicago, IL

Interendothelial slits in the spleen fulfill the major physiological function of continuously filtering red blood cells (RBCs) from the bloodstream to remove abnormal and aged cells. To date, the process of passage of 8 µm RBCs through 0.3-µm wide slits remains enigmatic. Should the slits increase their caliber during RBC passage as sometimes proposed in the literature? Here, we elucidated the mechanisms that govern the passage dynamics or retention of RBCs in slits by combining multiscale modeling, live imaging, and microfluidic experiments on an original device with slits of defined physiological dimensions, including submicron width. We observed that healthy RBCs pass through 0.28-µm wide rigid slits at body temperature. To achieve this tour de force, they must meet two requirements. Geometrically, their surface area-to-volume ratio must be compatible with a shape in two tether-connected equal spheres. Mechanically, they must be able to locally unfold their spectrin cytoskeleton inside the slits. In contrast, activation of the mechanosensitive PIEZO1 channel is not required. The RBC transit time through slits scales with in-slit pressure drop and slit width to the -1 and -3 power, respectively. This transit dynamics is similar to that of a Newtonian fluid in a 2D Poiseuille flow, thus showing that it is controlled by the RBC cytoplasmic viscosity. Altogether, our results clearly show that filtration through submicron-wide slits is possible without further slit opening. Furthermore, our approach addresses the critical need for in-vitro evaluation of splenic clearance of diseased or engineered RBCs for transfusion and drug delivery.

Disclosures: No relevant conflicts of interest to declare.

*signifies non-member of ASH