#3627 PHOSPHATIDYLSERINE EXPOSURE AND SHORTENED LIFE SPAN OF ERYTHROCYTES IN RENAL ANEMIA

Abstract Background and Aims The lifespan of erythrocytes in patients with renal anemia is shortened (∼70 days) compared to that healthy (120 days), but the pathological mechanisms causes are unclear. Senescent express phosphatidylserine (PS) on their outer membrane, which a signal for being removed by macrophages. PS localization cellular membrane mainly regulated two transporters: flippases scramblases. Flippases, type Ⅳ P-type ATPases (P4-ATPases), maintain inner leaflet transporting from cell membrane. When scramblases activated, they facilitate equal distribution phospholipids between lipid bilayers, resulting exposure leaflet. Recently, we have revealed reduced flippase activity contributes senescent [1]. In this study, examined percentage PS-exposed cells transporter elucidate mechanism lifespan. Method This study was approved Ethics Committee Tokyo Women's Medical University (#3835, #4822R2). Erythrocytes anemic undergoing maintenance hemodialysis were separated centrifugation using Percoll-density gradient according our previous report. Resultant heavy light fractions used as young erythrocytes, respectively. We analyzed (n = 12), flippase/scramblase activities 7), factors involved those enzymatic such intracellular K+ 10) ATP concentration 9). also measured protein 4.1a/b HbA1c an index erythrocytes’ age. Results (senescent) (young) fractions, similar distributions previously performed erythrocytes. fraction slightly more than (p < 0.01, Wilcoxon test), decreased paired t-test). Intracellular there no statistical difference fractions. measurement these still progress. Conclusion Similar anemia, maybe due concentration. may occur earlier stage senescence ones, explain life span.