Calcium dynamically alters erythrocyte mechanical response to shear

Area of Science:

• Biophysics
• Hematology
• Cell Physiology

Background:

• Red blood cells (RBCs) experience mechanical stress in the cardiovascular system.
• Calcium influx into RBCs triggers potassium efflux and cell volume reduction (Gárdos effect).
• Calcium's role in RBC mechanics and deformability requires further elucidation.

Purpose of the Study:

• To investigate the impact of calcium on RBC biomechanical properties.
• To analyze calcium's effects on RBC geometry and deformability under shear stress.
• To elucidate the mechanism of calcium-mediated regulation of RBC mechanics.

Main Methods:

• RBCs were mechanically stimulated using a co-axial Couette shearing system.
• Intracellular calcium levels were manipulated using ionophore A23187.
• Cellular responses were monitored using fluorescent imaging and high-precision geometrical analysis.

Main Results:

• Increased intracellular calcium significantly impaired RBC deformability.
• Calcium-induced cell volume reduction via the Gárdos channel mediated these impairments.
• Extracellular calcium induced RBC lysis under shear, suggesting removal of older cells.

Conclusions:

• Calcium acutely regulates RBC mechanical properties, primarily through Gárdos channel-mediated volume reduction.
• Extracellular calcium plays a role in RBC lysis and potential removal of aged cells under shear stress.
• This study provides mechanistic insights into calcium's dynamic effects on RBC biomechanics.