Studies on the Adhesiveness of in vivo Aged Erythrocytes

通过测量(I)红细胞聚集和解离的速度，以及(Ii)红细胞与玻璃平板上人工复制的红细胞膜的相互作用，研究了体内老化红细胞的粘附性。(1)经Percoll密度梯度离心法分离的人老化红细胞比年轻红细胞更聚集和更粘连。(2)正常大鼠产生的红细胞在血浆中的聚集速度大于重组人促红细胞生成素注射大鼠(在骨髓中通过促红细胞生成素刺激产生年轻红细胞)。(3)红细胞膜表面结构的重要性，特别是红细胞膜表面结构的重要性。血糖素A的结构变化对红细胞聚集和红细胞间的粘附性有很大的贡献。这些现象被认为是一种体内老化的红细胞模型，特别是考虑到红细胞在循环中的存活。结论是，体内老化过程中红细胞粘附性的增加以及变形能力的降低有助于这些老化的红细胞在网状内皮系统中的去除。在老化的红细胞在网状内皮系统中受损通过的过程中，红细胞表面膜蛋白的结构变化(衰老抗原的出现)是由巨噬细胞感知的。

Adhesiveness of in vivo aged erythrocytes was studied by measuring (i) the velocity of erythrocyte aggregation and the dissociation of the aggregates, and (ii) the interaction of erythrocytes with artificially reproduced erythrocyte membrane on the glass plate.(1) Human aged erythrocytes fractionated by a density gradient centrifugation with Percoll were more aggregative and more adhesive than young erythrocytes.(2) Aggregation velocity of erythrocytes normally produced in rats was greater in plasma than that of erythrocytes produced in recombinant human erythropoietin-administered rats (in which young erythrocytes were produced in bone marrow by erythropoietin stimulation).(3) Importance of membrane surface structure of erythrocytes, particularly, the great contribution of the structural change of glycophorin A, was shown for the erythrocyte aggregation and the adhesiveness among erythrocytes. The phenomena were proposed as a model of in vivo aged erythrocytes, with a special regard to survival of erythrocytes in circulation.In conclusion, increased adhesiveness of erythrocytes during in vivo aging in addition to the decreased deformability contributes to the removal of these aged erythrocytes in the reticuloendotherial system. In the process of impaired passage of aged erythrocytes in the reticuloendothelial system, the structural change of surface membrane proteins of the erythrocytes (the appearance of "senescent antigen" ) is sensed by macrophages.