Crystal Aggregation in Kidney Stone

描述（由申请人提供）：肾结石形成为各种矿物相的聚集体，但一水草酸钙（COM）是最常见的。之前的研究都未能通过尿液检查来确定结石形成者，也未能有效地预防结石形成。我们假设正常健康成人尿液中的大分子可以阻止导致肾结石形成的病理聚集事件，并且肾结石患者在这种保护机制中表现出一些改变。在这一修订后的申请中，我们建议结合使用体结晶和微观表征方法来识别导致聚集抑制缺陷的大分子的特定化学结构特征，通过一个有两个特定目标的研究方案。两个具体目标是：(1)使用先前建立的体结晶方法来研究单个大分子（来自生物或化学来源）以及聚阴离子和聚阳离子的组合，以确定对COM聚集过程至关重要的化学结构特征；(2)使用原子力显微镜直接测量Aim 1研究的大分子对特定COM晶面粘附力的影响。在这些研究的后期阶段，我们将使用原子力显微镜直接测量在溶液中存在各种大分子时取向晶体表面之间的附着力。AFM的使用将提供含有特定化学官能团的大分子与选定的COM表面吸附的重要信息，这是任何其他方式无法获得的。我们的初步数据显示了面选择性结合与晶体相和形态之间的重要相关性。将特定化学官能团的链接扩展到聚集过程将允许智能设计药物，通过阻止聚集过程来防止结石的形成。

DESCRIPTION (provided by applicant): Kidney stones form as aggregates of various mineral phases, but calcium oxalate monohydrate (COM) is the most prevalent. Prior research efforts have failed to identify either a urine test that identifies stone formers or effective therapies preventing stone formation. We hypothesize that macromolecules in the urine of normal healthy adults prevent the pathologic aggregation events that lead to kidney stone formation, and that stone formers manifest some alteration in this protective mechanism. In this revised application, we propose to use a combination of bulk crystallization and microscopic characterization methods to identify specific chemical structural features of macromolecules that lead to a defect in aggregation inhibition, through a research protocol with two Specific Aims. The two Specific Aims are: (1) to use previously established bulk crystallization methods to study single macromolecules (from either biological or chemical origins) and combinations of polyanions and polycations to identify the chemical structural features critical to the COM aggregation processes and (2) to use atomic force microscopy to directly measure the influence of macromolecules studied under Aim 1 on the force of adhesion at specific COM crystal faces. In the later phases of these studies, we will use atomic force microscopy to measure directly the adhesion force between oriented crystal surfaces in the presence of various macromolecules in solution. The use of AFM will provide important information about the adsorption of macromolecules containing specific chemical functional groups with selected COM surfaces, that is not obtainable in any other way. Our preliminary data have shown important correlations between face selective binding and crystal phase and morphology. Extending the linkage of specific chemical functional groups to the aggregation process will allow for the intelligent design of drugs that could prevent stone formation by blocking aggregation processes.