Reversibility of Red blood Cell deformation

TL;DR

This paper presents a theoretical analysis of how red blood cells respond to mechanical stress, revealing mechanisms behind their reversible or irreversible shape changes and implications for conditions like anemia.

Contribution

It introduces a theoretical model explaining the role of cytoskeletal stress and transient protein polymerization in RBC shape reversibility and shape relaxation dynamics.

Findings

Cytoskeletal tensile stress can cause irreversible RBC deformation.

Transient protein fiber polymerization influences shape change.

Relaxation kinetics determine the final cell shape after perturbation.

Abstract

The ability of cells to undergo reversible shape changes is often crucial to their survival. For Red Blood Cells (RBCs), irreversible alteration of the cell shape and flexibility often causes anemia. Here we show theoretically that RBCs may react irreversibly to mechanical perturbations because of tensile stress in their cytoskeleton. The transient polymerization of protein fibers inside the cell seen in sickle cell anemia or a transient external force can trigger the formation of a cytoskeleton-free membrane protrusion of micrometer dimensions. The complex relaxation kinetics of the cell shape is shown to be responsible for selecting the final state once the perturbation is removed, thereby controlling the reversibility of the deformation. In some case, tubular protrusion are expected to relax via a peculiar "pearling instability".