PATHOGENESIS OF HUMAN NEPHROLITHIASIS

该项目涉及抑制人体肾脏晶体形成的分子。形成结石的男性与正常男性的不同之处在于，产生的尿液在减缓草酸钙晶体生长方面效果较差，而且草酸钙和磷酸钙产生结晶所需的过饱和和过饱和之间的距离（亚稳态上限，ULM）都缩短了。我们建议在女性中进行一项平行研究，以确定她们的结石机制是否与男性不同，并在我们已经描述过的男性结石患者的家庭成员中进行研究，以确定生长抑制和ULM到过饱和距离的降低是否具有家族性。在与项目2的合作中，我们建议确定抑制作用的减少是否与兰德尔斑块数量和表面积相关。鉴于男性生长抑制缺陷，我们建议通过对异常钙粒蛋白分子大小分布和特定生长抑制活性的初步观察，以及通过对比患者和对照组透析尿液分子对草酸钙晶体产生同等程度生长抑制的结合蛋白，来确定负责的分子。我们将通过确定EDTA溶解对尿分子生长抑制的影响，探索尿液中结晶消耗高亲和力抑制剂降低其可用性的可能性。最后，我们计划进行类似的实验，通过对比患者和正常人在体外尿液过饱和度高于ULM时产生的与草酸钙和磷酸钙晶体结合的分子，来确定导致ULM减少到过饱和距离的分子。我们还将探讨尿焦磷酸盐减少或尿柠檬酸盐与尿pH之间的异常关系可能导致患者ULM减少的可能性。

This project concerns the molecules that inhibit formation of crystals in human kidneys. Males who form stones differ from normal males in producing urine less effective in slowing the growth of calcium oxalate crystals, and in which the distance between supersaturation and the supersaturation needed to produce crystallization (upper limit of metastability, ULM) is reduced for both calcium oxalate and calcium phosphate. A parallel study is proposed in women, to determine if their mechanisms of stones differ from those in men, and in family members of the male stone formers we have already characterized, to determine if reduced growth inhibition and ULM to supersaturation distance is familial. In collaboration with Project 2, we propose to determine if reduced inhibitions correlate with Randall's plaque number and surface area. Given the male growth inhibition defect, we propose to identify molecules responsible by pursuing our initial observation of aberrant calgranulin molecular size distribution and specific growth inhibition activity, and by contrasting proteins bound to calcium oxalate crystals brought to equivalent degrees of growth inhibition by patient and control dialyzed urine molecules. We will explore the possibility that crystallization in urine consumes high affinity inhibitors reducing their availability, by determining the effects of EDTA dissolution on growth inhibition by urine molecules. Finally, we plan similar experiments to identify molecules responsible for the reduced ULM to supersaturation distance by contrasting molecules from patients and normals bound to the calcium oxalate and calcium phosphate crystals produced as their urine supersaturation is raised above the ULM in vitro. We will also explore the possibility that reduced urine pyrophosphate or an abnormal relationship between urine citrate and urine pH may contribute to the reduced ULM in patients.