PATHOGENESIS OF ISCHEMIC RENAL DISEASE

尽管细胞能量耗尽是暂时性组织的特征 缺血，初始细胞损伤残留的发病机制(S) 未知。大量对不同模型和组织的研究表明 一些潜在的致病机制可以解释 缺血性细胞损伤。一种方案可以统一这些观测结果和 作为这项提议的中心主题，就是严重的腺嘌呤 核苷酸(ATP)耗竭导致胞浆延长升高 CA2(Cai)。持续的蔡氏指数上升被认为激活了关键 依赖于钙的酶，如细胞磷脂酶和/或蛋白酶 催化质膜和细胞器膜的快速降解 随后释放和积累有毒的脂类代谢物。结果 和膜破裂和/或游离脂肪酸的去污剂特性 可以允许细胞CaI进一步增加。此外，钙激活 这些过程可能会破坏维护所需的细胞骨架结构 并直接损伤线粒体。此外，损失 小细胞蛋白，如肾脏脂肪酸结合蛋白，能够 缓冲有毒的游离脂肪酸的上升，可能会加剧这种情况 周而复始。最后，细胞骨架结构丧失的综合侮辱， 游离脂肪酸和细胞CaI可为不可逆膜提供燃料 崩溃了。这项提案将检查每一个潜在的致病因素 影响细胞CaI变化的因素及其相互关系。我们还将调查 几种潜在保护性动作的机制，如 细胞外酸中毒或热休克的诱导 蛋白质作为进一步识别重要生化事件的手段 是缺血性细胞损伤的基础。在这些研究中，有三种不同的 将利用体外模型：小鼠近端小管的原代培养 细胞；大鼠近端小管和分离的红细胞的悬液 灌流的肾脏。这些模式中的每一种都提供了独特和互补的 以解决这些问题为目的的优势。

Although cellular energy depletion is a hallmark of transient tissue ischemia, the pathogenic mechanism(s) that initial cell injury remain unknown. A host of studies in disparate models and tissues have suggested a number of potentially pathogenic mechanisms that could account for ischemic cell injury. One scheme that could unify these observations and serves as the central theme of this proposal, is that severe adenine nucleotide (ATP) depletion precipitates prolonged elevation of cytosolic Ca2+ (Cai). The prolonged increase in Cai is thought to activate critical Ca-dependent enzymes such as cell phospholipases and/or proteases that catalyze rapid degradation of plasma and organelle membranes with the subsequent release and accumulation of toxic lipid metabolites. Result and membrane breakdown and/or the detergent properties of free fatty acids could permit further increases in cell Cai. In addition, Ca-activated processes could disrupt cytoskeletal structures required for maintenance of cell function and directly injure mitochondria. Furthermore, loss of small cell proteins such as kidney fatty acid binding proteins, capable of buffering the rise in toxic, free fatty acids, could exacerbate this cycle. Finally, the combined insult of loss of cytoskeletal structures, unbound fatty acids and cell Cai could fuel irreversible membrane breakdown. This proposal will examine each of these potential pathogenic factors and their relationship to changes in cell Cai. We will also probe the mechanism of several potentially protective maneuvers such as the imposition of extracellular acidosis or the induction of heat shock proteins as a means to further identify important biochemical events that are the basis of ischemic cell injury. In these studies three different in vitro models will be utilized: primary cultures of mouse proximal tubule cells; suspensions of rat proximal tubules and the isolated erythrocyte perfused kidney. Each of these models provide unique and complementary advantages for the purposes of addressing these issues.