Inhibition of suicidal erythrocyte death by vitamin C

Abstract 

Objective

Similar to apoptosis of nucleated cells, suicidal death of erythrocytes is paralleled by cell shrinkage and cell membrane disorganization with phosphatidylserine exposure at the erythrocyte surface. Triggers of suicidal erythrocyte death include cell shrinkage, energy depletion, and oxidative stress, challenges at least partially effective by increasing the cytosolic Ca²⁺ concentration. Apoptosis is inhibited by vitamin C. The present study thus explored whether vitamin C similarly influences suicidal erythrocyte death.

Methods

The cytosolic Ca²⁺ concentration was estimated from Fluo3 fluorescence, phosphatidylserine exposure from annexin V-binding, and cell volume from forward scatter in fluorescence activated cell sorting (FACS) analysis.

Results

Energy depletion (48 h glucose removal) increased the cytosolic Ca²⁺ concentration, decreased the erythrocytic cell volume, and enhanced annexin V-binding. Similarly, cell shrinkage by 48 h replacement of extracellular chloride with gluconate and oxidative stress (30 min exposure to 0.3 mM tert-butylhydroperoxide) triggered suicidal erythrocyte death as evident from enhanced annexin V-binding. Vitamin C (up to 0.28 mM) did not significantly modify the cytosolic Ca²⁺ concentration, annexin V-binding, and cell volume in the absence of stressors stimulating suicidal erythrocyte death but significantly attenuated the suicidal erythrocyte death following cell shrinkage, energy depletion, and oxidative stress.

Conclusion

Vitamin C is a potent inhibitor of suicidal erythrocyte death.

Keywords: Phosphatidylserine, Cell membrane disorganization, Calcium, Cell volume, Apoptosis