PATHOGENESIS OF ISCHEMIC RENAL DISEASE

虽然细胞能量耗尽是短暂性组织损伤的标志 缺血，最初细胞损伤仍然存在的致病机制 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 有一个方案可以统一这些观察结果， 作为这个建议的中心主题，是严重的腺嘌呤， 核苷酸（ATP）耗竭可导致细胞内 Ca2+（CaI）。 蔡的长期增加被认为是激活关键的 Ca依赖性酶，如细胞磷脂酶和/或蛋白酶， 催化血浆和细胞器膜的快速降解， 随后释放和积累有毒脂质代谢物。 结果 和膜破裂和/或游离脂肪酸的洗涤剂性质 可以允许细胞Cai的进一步增加。 此外，钙激活 这些过程可能会破坏细胞维持所需的细胞骨架结构 破坏细胞功能并直接损伤线粒体。 此外，损失 小细胞蛋白质如肾脂肪酸结合蛋白，能够 缓冲有毒的游离脂肪酸的增加，可能会加剧这种情况。 周期 最后，细胞骨架结构的丧失， 未结合的脂肪酸和细胞Cai可以为不可逆膜提供燃料 崩溃 这项提案将审查每一个潜在的致病性 因素及其与细胞Cai变化的关系。 我们还将探索 几种潜在的保护性机动的机制，如 施加细胞外酸中毒或诱导热休克 蛋白质作为一种手段，以进一步确定重要的生化事件， 是缺血性细胞损伤的基础。在这些研究中， 将使用体外模型：小鼠近端小管的原代培养物 细胞;大鼠近端小管和分离的红细胞悬液 灌注肾。 这些模型中的每一个都提供了独特的和互补的 为解决这些问题的目的。

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.