MECHANISMS OF VANCOMYCIN-INDUCED NEPHROTOXICITY

万古霉素（货车）是一种阳离子糖肽类抗生素，用于治疗 各种革兰氏阳性菌感染 货车被认为是一种潜在的 耳毒性和肾毒性剂。 报告的肾毒性发生率 在人类中是高度可变的，范围从5%到17%。 发生率 当使用货车时， 同时使用氨基糖苷类抗生素。 动物研究 评价钒酸铵引起的肾毒性的机制是不完整的 并且主要是描述性的。 关于这一点，我们知之甚少。 货车在肾脏内的肾脏蓄积机制， 已知的机制涉及生产 肾毒性 该实验室开发了一个模型， 雌性Sprague-Dawley（SD）大鼠的肾毒性。 肾毒性是 通过一些功能和结构的改变来证明。 这些 变化包括血尿素氮（BUN）浓度升高， 降低的造血能力和降低的积累能力 有机离子 肾脏重量增加，原因是肾脏总重量增加 还观察到水、蛋白质和磷脂。 大鼠预处理 与聚天冬氨酸（PAA），在货车管理，防止 肾毒性，似乎与肾货车蓄积有关。 的 这一建议所基于的前提是货车必须累积 在肾细胞内，以产生肾毒性。 一旦进入 细胞，货车与肾脏蛋白质和磷脂相互作用的水平 关键的膜系统，如质膜， 线粒体膜 这些改变导致了 肾细胞转运特性和能量产生，然后 转化为肾毒性反应 说这一点是为 描述肾细胞内货车蓄积的机制， 然后确定货车产生肾毒性的机制。 这些机制将根据具体地点的反应加以处理 近端和远端肾小管细胞的货车。 这一目标将 通过采取综合的、机械的方法来实现 问题. 将在体内和体外测定肾货车蓄积。 近端和远端肾小管细胞在膜上生长的原代培养 支持物将用于确定顶侧与基底侧摄取 货车 血管紧张素Ⅱ诱导的磷脂质沉积和增加的机制 蛋白质含量将通过评价合成来确定， 降解 货车对线粒体和质膜的影响 磷脂谱将通过HPLC分离关键的 磷脂 这些变化将与血浆中的 膜（顶侧和基底侧）转运能力和线粒体 能源生产。 对相互作用性质的进一步审查 货车和PAA之间的关系可能会为货车的机制提供更多的信息 与肾组织的相互作用。 PAA干扰的机制 将通过竞争性结合研究评价肾货车蓄积 在整个细胞和膜组分上。 从这里收集的数据 建议应提供有关机制的重要信息 为进一步的研究奠定基础 近端和远端肾小管细胞对 毒物引起的损伤

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.