ERYTHROCYTE SENESCENCE

红细胞衰老的机制仍然是一个未解之谜。 问题. 尽管对遗传决定的溶血性贫血的研究 已经证明了各种缺陷， 寿命，没有明确的答案已经出现的正常机制 决定红细胞的存活 对这种衰老的研究 隔离老年人的技术困难阻碍了这一进程 细胞 从历史上看，各种物理技术已经被利用 但大多数不能令人满意。 这项建议采用了一种分离衰老细胞的方法， 来自兔的红细胞，其中细胞被共价标记有 生物素与N-羟基琥珀酰亚胺生物素反应。 结合的生物素具有 当衍生的细胞被 重新注入兔子体内 在衍生化后的不同时间和 在体内老化时，生物素化的红细胞可以通过以下方式选择性地恢复： 它们对抗生物素蛋白支持物的亲和力。 通过这种方法，红细胞 通常在预期死亡后5至10天内被隔离。 这 一项提案将研究红细胞中脂质过氧化作用的参与， 通过定量丙二醛-蛋白质加合物水平的老化过程 在衰老细胞中，通过定量脂质过氧化氢的水平， 红细胞年龄的功能，并通过确定血红素和非血红素的量 与衰老细胞膜相关的铁。 此外，国家 将评价老化红细胞中几种膜组分的含量，包括 唾液酸水平、带3的完整性和 细胞表面的补体成分。 另外， 腺苷5 '-单磷酸脱氨酶活性的年龄依赖性丧失 红细胞将被检查。 仔细检查这些 参数将有助于评估与 红细胞老化过程，并导致更好地了解这些 控制红细胞正常衰老的因素。

The mechanism responsible for erythrocyte senescence remains an unsolved problem. Even though the study of genetically determined hemolytic anemias has demonstrated a variety of defects which can shorten the erythrocyte life span, no clear cut answer has emerged as to the normal mechanisms which determine erythrocyte survival. The examination of this aging process has been hindered by the technical difficulty of isolating aged cells. Historically a variety of physical techniques have been utilized for obtaining these senescent erythrocytes but most are not satisfactory. This proposal employs a procedure for the isolation of senescent erythrocytes from the rabbit in which the cells are covalently labeled with biotin by reaction with N-hydroxysuccinimido biotin. The bound biotin has been shown to not affect in vivo survival when the derivatized cells are re-infused into the rabbit. At various times after derivatization and in vivo aging, the biotinylated erythrocytes can be selectively recovered by their affinity for an avidin support. With this procedure, erythrocytes are routinely isolated within 5 to 10 days of their expected death. This proposal will examine the involvement of lipid peroxidation in the red cell aging process by quantitating the level of malondialdehyde-protein adducts in senescent cells, by quantitating the level of lipid hydroperoxides as a function of red cell age and by determining the amount of heme and non-heme iron associated with the senescent cell membrane. Additionally, the state of several membrane components in aged red cell will be evaluated including the levels of sialic acid, the integrity of band 3 and the level of complement components on the cell surface. Also, the mechanism responsible for the age-dependent loss of adenosine 5'-monophosphate deaminase activity in the red cell will be examined. A careful examination of these parameters will facilitate evaluation of specific hypotheses related to the red cell aging process and result in a better understanding of those factors which control the normal senescence of erythrocytes.