Prevention of Kidney Stone Crystal Retention

描述（由申请人提供）：肾结石是一种严重的医疗问题，会导致发病率，并因急诊室就诊、药物治疗和碎石术或其他手术而产生费用。这项工作的长期目标是生产一种晶体沉积抑制剂，适用于人体测试。这项工作的总体假设是，晶体附着抑制剂将是临床肾结石的有效治疗药物。具体目标如下：1.检测分子抑制草酸钙一水合物（COM）晶体附着于内髓集合管（IMCD）细胞或彼此附着的能力。我们将测试阴离子均聚物聚（天冬氨酸），聚（谷氨酸），聚（丙烯酸）酸，以确定最有效的抑制剂COM晶体附着IMCD细胞和彼此，分别使用体外细胞培养和聚集试验。此外，我们还将确定具有其他阴离子功能位点的聚合物，聚（丝氨酸），硫酸化碳水化合物enoxiparin和戊聚糖，一些含唾液酸的寡糖，磷酸化蛋白质和肽均聚物，是否对晶体附着有类似的效果。2.在实验动物中测试晶体附着到培养细胞的抑制剂改善晶体沉积的能力。当使用植入式渗透微型泵给药时，将检测聚阴离子和含有可能干扰晶体附着的其他官能团的小至中等分子量聚合物抑制用乙二醇和NH 4Cl处理的大鼠中草酸钙晶体沉积的能力。我们还将通过用荧光染料或生物素标记化合物以允许检测来确定草酸钙晶体保留的有效抑制剂向尿液的递送。还将测量这些动物的肾功能，以寻找早期肾毒性。3.确定口服时哪些抑制剂有效。将测试当使用植入式微型泵给药时有效防止草酸钙晶体滞留的抑制剂在口服给药时抑制晶体滞留的能力。将根据需要采用给药方案、喂养策略、全身性药物或伴随药物，以通过口服途径递送足量的抑制剂。4.确定有效的抑制剂是否具有显著的中短期全身毒性和肾毒性。几种经口给药有效的抑制剂将以其有效剂量的5-10倍给予大鼠长达180天。将观察动物的一般健康状况，生病或研究期结束的动物将进行一系列完整的实验室检查。对所有患病动物和研究期结束时健康的选定动物进行尸检。在本项目结束时，我们预计将有三种药物适用于更全面的动物毒性研究，可能由具有满足FDA要求经验的商业实验室进行。如果它们中的任何一种适当地没有毒性，将考虑进行人体第一阶段试验，大概是由持牌人进行。

DESCRIPTION (provided by applicant): Kidney stones are a significant medical problem, causing morbidity and entailing expenses due to emergency room visits, medications, and lithotripsy or other procedures. The long-term goal of this work is to produce an inhibitor of crystal deposition that would be suitable for testing in humans. The overall hypothesis of this work is that inhibitors of crystal attachment will be effective therapeutic agents in clinical nephrolithiasis. Specific objective are as follows: 1. To test molecules for the ability to inhibit calcium oxalate monohydrate (COM) crystal attachment to inner medullary collecting duct (IMCD) cells or to one another. We will test the anionic homopolymers poly(aspartic), poly(glutamic), and poly(acrylic) acids to determine the most effective inhibitors of COM crystal attachment to IMCD cells and to each other, using in vitro cell culture and aggregation assays, respectively. In addition, we will determine whether polymers with other anionic functional sites, poly(serine), the sulfated carbohydrates enoxiparin and pentosan, some sialie acid-containing oligosaccharides, and phosphorylated proteins and peptide homopolymers, have similar ef- fects on crystal attachment. 2. To test inhibitors of crystal attachment to cultured cells for their ability to ameliorate crystal deposition in ex- perimental animals. Polyanions and small to intermediate MW polymers containing other functional groups that may interfere with crys- tal attachment will be tested for their ability to inhibit calcium oxalate crystal deposition in rats treated with ethylene glycol and NH4C1 when administered using implanted osmotic minipumps. We will also determine the delivery to urine of effective inhibitors of calcium oxalate crystal retention by labeling compounds with fluorescent dyes or with biotin to permit detection. Renal function will also be measured in these animals to look for early renal toxicity. 3. To determine which of the inhibitors are effective when given orally. Inhibitors that are effective at preventing calcium oxalate crystal retention when administered using the implanted minipumps will be tested for their ability to inhibit crystal retention when given orally. Dosage regimens, feeding strategies, systemic medications, or accompany- ing agents will be employed as necessary to deliver adequate amounts of inhibitors via the oral route. 4. To determine whether the effective inhibitors have significant short and intermediate-term general and renal toxicity. Several inhibitors that are effective with oral dosing will be administered to rats at 5-10 times their effective doses for up to 180 days. Animals will be observed for general well being, and those that become sick or reach the end of the study period will have a complete battery of laboratory tests drawn. All ill animals and a selection of animals that appear healthy at the end of the study period will have necropsies performed. At the conclusion of this project, we expect to have three agents suitable for more comprehensive animal toxicity studies, presumably performed by a commercial laboratory with experience in satisfying FDA requirements. Should any of them be suitably free of toxicity, Phase I testing in human would be contemplated, presumably by a licensee.