MECHANISMS OF VANCOMYCIN-INDUCED NEPHROTOXICITY

万古霉素(VAN)是一种阳离子糖肽抗生素，用于治疗 各种革兰氏阳性感染。范被认为是一个潜在的 耳毒性和肾毒剂。肾毒性的报告发生率 在人类中是高度可变的，范围从5%到17%。发病率 使用VAN时，肾毒性的发生率高达35% 同时使用氨基糖苷类抗生素。动物研究 对凡士林所致肾毒性机制的评价尚不完整 而且大多是描述性的。人们对此知之甚少 凡士林在肾脏内蓄积的机制 已知的是参与生产的机制 肾毒性。本实验室开发了一种货车诱导的模型。 雌性SD大鼠的肾毒性。肾毒性是 一些功能和结构上的改变证明了这一点。这些 变化包括血液尿素氮(BUN)浓度的升高， 糖异生能力下降，蓄积能力下降 有机离子。总肾重量增加所致的肾重量增加 水、蛋白质和磷脂也被观察到。大鼠的前处理 使用聚天冬氨酸(PAA)，在给VAN之前，防止 肾毒性，似乎与肾VAN蓄积有关。这个 这项建议的前提是，货车必须积累起来 在肾细胞内产生肾毒性。一旦进入 细胞，VAN与肾脏蛋白质和磷脂在水平上相互作用 关键的膜系统，如质膜和 线粒体膜。这些变化导致了细胞的失调。 肾细胞运输特性和能量产生，然后是 转化为肾毒性反应。这项建议的目的是 为了阐明VAN在肾细胞内蓄积的机制，以及 然后确定VAN产生肾毒性的机制。 这些机制将在特定地点的反应方面加以解决 近端和远端肾小管上皮细胞的数量。这个目标将是 通过采用集成的机械化方法来实现 有问题。肾内VAN蓄积将在体内和体外进行测定。 膜上生长的近、远端肾小管细胞的原代培养 支撑物将被用来确定根尖与基底外侧的摄取 面包车。血管紧张素转换酶诱导的磷脂沉积和升高的机制 蛋白质含量将通过评估合成和 退化。VAN对线粒体膜和质膜的影响 磷脂图谱将通过关键的高效液相分离进行评估 磷脂。这些变化将与血浆中的变化相关 膜(顶端和基底外侧)转运能力与线粒体 能源生产。对相互作用性质的进一步考察 VAN和PAA之间的关系可能会为VAN的机制提供更多线索 与肾组织的相互作用。PAA干扰的机制 肾VAN蓄积将通过竞争性结合研究进行评估 在整个细胞和膜部分上。从这里收集的数据 建议书应提供有关机制的重要信息 并为今后的研究奠定了基础 近端肾小管与远端肾小管上皮细胞对 毒物引起的伤害。

Vancomycin (VAN) is a cationic glycopeptide antibiotic used to treat a variety of gram-positive infections. VAN is regarded as a potentially ototoxic and nephrotoxic agent. The reported incidence of nephrotoxicity in humans is highly variable and ranges from 5% to 17%. The incidence of nephrotoxicity increases to as high as 35% when VAN is used concomitantly with an aminoglycoside antibiotic. Animal studies evaluating the mechanisms of VAN-induced nephrotoxicity are incomplete and mostly descriptive in nature. Little is known regarding the mechanisms for renal accumulation of VAN within the kidney and nothing is known about the mechanisms involved in the production of nephrotoxicity. this laboratory has developed a model for VAN-induced nephrotoxicity in the female Sprague-Dawley (SD) rat. Nephrotoxicity is demonstrated by a number of functional and structural alterations. These changes include elevations in blood urea nitrogen (BUN) concentrations, decreased gluconeogenic capacity and decreased ability to accumulate organic ions. Increases in kidney weight due to increases in total renal water, protein and phospholipid are also observed. Pretreatment of rats with polyaspartic acid (PAA), prior to VAN administration, prevents nephrotoxicity and appears to be linked to renal VAN accumulation. The premise on which this proposal is based is that VAN must be accumulated within renal cells in order to produce nephrotoxicity. Once inside the cells, VAN interacts with renal proteins and phospholipids at the level of critical membrane systems such as the plasma membrane and mitochondrial membrane. These alterations result in dysregulation of renal cell transport properties and energy production, which are then translated into a nephrotoxic response. The purpose of this proposal is to delineate the mechanisms for VAN accumulation within renal cells and then determine the mechanisms by which VAN produces nephrotoxicity. These mechanisms will be addressed in terms of site-specific responses of proximal & distal tubular cells to VAN. This goal will be accomplished by taking an integrated, mechanistic approach to the problem. Renal VAN accumulation will be determined in vivo and in vitro. Primary cultures of proximal and distal tubular cells grown on membrane supports will be used to determine the apical vs basolateral uptake of VAN. The mechanisms for VAN-induced phospholipidosis and increased protein content will be determined by evaluating synthesis and degradation. The effects of VAN on mitochondrial and plasma membrane phospholipid profiles will be evaluated by HPLC separation of key phospholipids. These alterations will be correlated to changes in plasma membrane (apical and basolateral) transport ability and mitochondrial energy production. Further examination on the nature of the interaction between VAN and PAA may shed some more light into the mechanisms for VAN interactions with renal tissue. the mechanism for PAA interference with renal VAN accumulation will be evaluated by competitive binding studies on whole cells and membrane fractions. The data gathered from this proposal should provide significant information regarding the mechanisms of VAN-induced nephrotoxicity and lay the groundwork for future studies on differential susceptibility of proximal vs distal tubular cells to toxicant-induced injury.