Continuous Treatment with Oxalate Changes Renal Physiology and Morphology (DK0750

描述（由申请方提供）：草酸盐在草酸钙（CaOx）肾钙质沉着症和草酸盐驱动的肾结石中的作用尚不清楚。越来越多的证据表明，除了晶体形成，草酸盐通过与肾上皮、肾小管和血管系统的相互作用促进这些条件。对这些影响的不同易感性可能部分解释了为什么具有相似风险因素的个体没有相似的临床症状。该提案将利用两个版本的微型泵模型来研究这些相互作用。标准14 D方案模拟中度至重度高尿酸血症，因为它诱导草酸盐排泄增加大于或等于3倍和小管内CaOx-肾钙质沉着。LongDose方案将通过在4周时间内诱导草酸盐排泄增加小于或等于1.5- 2倍以及诱导混合CaOx-/CaP-肾钙质沉着来模拟更常见的轻度至中度高尿症。该建议的一个新的方面是，离子色谱法和偏光显微镜/ Yasue染色+形态分析将被用来关联草酸盐对肾单位，肾小管或血管的特定部分与肾内草酸盐浓度和晶体沉积的影响。剂量反应和时间过程研究将确定晶体沉积之前发生的变化，从而可能促进肾钙质沉着症。在特定目标1中，将确定360 μ M KOx/24小时持续14 D对肝功能、心肌病和骨重建的影响，并将开发LongDose方案。特异性目标2将利用RT-PCR、北方和西方印迹和免疫荧光来鉴定在连续、稳定暴露于草酸盐期间节段特异性、一般性痛苦、脉管系统痛苦和结石病标记物表达的变化。具体目标3将利用透射电子显微镜和免疫荧光来识别肾单位的节段以及在连续、稳定暴露于草酸盐期间显示形态学损伤、凋亡或增殖的肾小管和脉管系统的区域。与公共卫生的相关性：该提议使用大鼠微型泵模型研究在CaOx-肾钙质沉着症和草酸盐驱动的结石病的早期阶段期间草酸盐对肾脏的特定区域的影响。目的是确定促进这些条件的影响。未来的工作将确定这些影响的机制，目标是开发有效的预防性治疗。

DESCRIPTION (provided by applicant): The role that oxalate plays in calcium oxalate (CaOx) nephrocalcinosis and oxalate driven nephrolithiasis is not well understood. There is accruing evidence that in addition to crystal formation, oxalate promotes these conditions through its interactions with the renal epithelium, interstitium and vasculature. Differing susceptibilities to these effects may partially explain why individuals with similar risk factors have do not have similar clinical symptoms. This proposal will utilize two versions of the minipump model to study these interactions. The standard 14D protocol models moderate-to-severe hyperoxaluria in that it induces a greater than or equal to 3x increase in oxalate excretion and intratubular CaOx-nephrocalcinosis. The LongDose protocol will model the more common mild-to-moderate hyperoxaluria by inducing less than or equal to 1.5-2x increase in oxalate excretion over a 4wk period and the induction of mixed CaOx-/CaP- nephrocalcinosis. A novel aspect of this proposal is that ion chromatography and polarizing microscopy/ Yasue staining + morphometric analysis will be used to correlate oxalate's effects on specific segments of the nephron, interstitium or vasculature with intrarenal oxalate concentrations and crystal deposition. Dose response and time course studies will identify those changes which occur prior to crystal deposition and thus could be fostering nephrocalcinosis. In Specific Aim 1, the effects of 360 muM KOx/24hr for 14D on liver function, cardiomyopathy, and bone remodiling will be determined and the LongDose protocol will be developed. Specific Aim 2 will utilize RT-PCR, Northern & Western blotting and immunofluorescence to identify changes in the expression of segment specific, general distress, vasculature distress and stone disease makers during continuous, steady exposure to oxalate. Specific Aim 3 will utilize transmission electron microscopy and immunofluorescence to identify segments of the nephron and regions of the interstitium and vasculature that show morphological damage, apoptosis or proliferation during continuous, steady exposure to oxalate. Relevance to Public Health: This proposal investigates oxalate's effects on specific regions of the kidney during the early phases of CaOx- nephrocalcinosis and oxalate driven stone disease using the rat minipump model. The objective is to identify those effects which promote these conditions. Future work will determine the mechanism of these effects with the goal of developing an effective preventative therapy.