衰老红细胞凋亡早期事件的研究，特别关注慢性肾衰竭时细胞内游离钙及磷脂不对称性丧失。

Investigation on the early events of apoptosis in senescent erythrocytes with special emphasis on intracellular free calcium and loss of phospholipid asymmetry in chronic renal failure.

作者信息

Sakthivel Ramasamy, Farooq Shukkur Muhammed, Kalaiselvi Periandavan, Varalakshmi Palaninathan

机构信息

Department of Medical Biochemistry, Dr ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India.

出版信息

Clin Chim Acta. 2007 Jul;382(1-2):1-7. doi: 10.1016/j.cca.2007.02.044. Epub 2007 Mar 6.

DOI:10.1016/j.cca.2007.02.044

PMID:17449019

Abstract

BACKGROUND

The pathophysiological link between increased blood concentrations of factors responsible for the derangement and erythrocyte membrane functions in chronic renal failure (CRF) patients are not thoroughly elucidated. We studied the erythrocyte characteristics and phospholipid asymmetry loss in CRF patients with different grades of uremia and also examined the involvement of intracellular free Ca(2+) in early events of apoptosis in uremic erythrocytes.

METHODS

The studied population consisted of 90, age and sex matched control subjects (Group I) and 238 CRF cases divided into 3 groups (Group II, III and IV) according to urea concentrations and complexity of secondary complications. Erythrocyte membrane fluidity determined by binding of MC540. Intracellular free Ca(2+) concentration was determined by the 2-wavelength method by using fluorescent calcium-sensitive probe FURA-2AM. Measurement of erythrocyte phosphatidylserine exposure by flow cytometry using Annexin V-FITC.

RESULTS

Cholesterol shedding increased with increasing severity of uremic complications. Erythrocytes from Group II show mild echinocyte or formation of spicules on the erythrocyte membrane surface whereas in Group III and IV they were echinocytic. Binding of MC540 was significantly higher with progression of uremic complications. Surface charge of uremic erythrocyte membrane was significantly reduced when compared with control subjects. Intracellular free Ca(2+) was positively correlated with binding of MC540 and surface hydrophobicity. The phosphatidylserine exposure of erythrocytes was significantly higher (p<0.001) in uremic patients when compared with controls.

CONCLUSIONS

Phosphatidylserine (PS) exposure erythrocytes were significantly increased in uremic patients when compared with controls. Uremic complications predisposes to membrane damages in erythrocytes.

摘要

背景

慢性肾衰竭（CRF）患者中，导致紊乱的因子血浓度升高与红细胞膜功能之间的病理生理联系尚未完全阐明。我们研究了不同程度尿毒症的CRF患者的红细胞特征和磷脂不对称性丧失情况，还检测了细胞内游离Ca(2+)在尿毒症红细胞凋亡早期事件中的作用。

方法

研究人群包括90名年龄和性别匹配的对照受试者（I组）以及238例CRF患者，根据尿素浓度和继发并发症的复杂性分为3组（II组、III组和IV组）。通过MC540结合测定红细胞膜流动性。使用荧光钙敏感探针FURA - 2AM通过双波长法测定细胞内游离Ca(2+)浓度。使用膜联蛋白V - FITC通过流式细胞术测量红细胞磷脂酰丝氨酸暴露情况。

结果

随着尿毒症并发症严重程度的增加，胆固醇脱落增加。II组患者的红细胞在细胞膜表面显示出轻度棘状红细胞或针状物形成，而III组和IV组则为棘状红细胞。随着尿毒症并发症的进展，MC540的结合显著增加。与对照受试者相比，尿毒症红细胞膜的表面电荷显著降低。细胞内游离Ca(2+)与MC540的结合及表面疏水性呈正相关。与对照组相比，尿毒症患者红细胞的磷脂酰丝氨酸暴露显著更高（p<0.001）。