Inhibition of suicidal erythrocyte death by resveratrol.
OBJECTIVE
Pleiotropic effects of resveratrol include antioxidant activity and inhibition of cyclooxygenase with decrease of PGE(2) formation. In erythrocytes oxidation and PGE(2) activate Ca(2+)-permeable cation channels. The Ca(2+)-entry leads to activation of Ca(2+)-sensitive K(+) channels with subsequent cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the erythrocyte surface. Cell shrinkage and phosphatidylserine exposure are hallmarks of suicidal erythrocyte death or eryptosis. Eryptotic cells adhere to the vascular wall thus compromising microcirculation and are cleared from circulating blood thus leading to anemia. The present experiments explored whether resveratrol influences eryptosis.


METHODS
Erythrocyte phosphatidylserine exposure was identified by annexin V-binding, cell volume estimated from forward scatter and cytosolic Ca(2+) activity determined utilizing Fluo3 fluorescence in FACS analysis.


RESULTS
Energy depletion (48 h glucose removal) significantly increased Fluo3 fluorescence and annexin V-binding and decreased forward scatter, effects significantly blunted by resveratrol (>/=5 microM). Moreover, oxidative stress (30 min 0.3 mM tert-butylhydroperoxide) and isoosmotic cell shrinkage (48 h replacement of extracellular chloride by gluconate) similarly triggered eryptosis, effects again significantly blunted in the presence of resveratrol.


CONCLUSIONS
Resveratrol is a potent inhibitor of suicidal erythrocyte death during energy depletion, oxidative stress and isoosmotic cell shrinkage. The nutrient could thus counteract anemia and impairment of microcirculation under conditions with excessive eryptosis.
Qadri
Syed M
SM
Department of Physiology, Eberhard-Karls-University of Tübingen, Gmelinstrasse 5, Tübingen, Germany.
Föller
Michael
M
Lang
Florian
F
D000263:Adenylate Kinase / Q000378:metabolism; D017304:Annexin A5 / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D002712:Chlorides / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology*
D017304:Annexin A5; D000975:Antioxidants; D002712:Chlorides; D013267:Stilbenes; D000263:Adenylate Kinase; D000077185:Resveratrol; D002118:Calcium