Continuous Treatment with Oxalate Changes Renal Physiology and Morphology (DK0750

描述（由申请人提供）：草酸盐在草酸钙（CaOx）肾钙化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，除了晶体形成外，草酸盐还通过与肾上皮、间质和脉管系统的相互作用促进这些疾病的发生。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。本提案将利用两个版本的迷你泵模型来研究这些相互作用。标准14D方案模型为中度至重度高草酸血症，因为它诱导草酸盐排泄增加大于或等于3倍，以及小管内caox肾钙化症。长剂量方案将模拟更常见的轻度至中度高草酸尿，在4周内诱导草酸排泄量增加小于或等于1.5-2倍，并诱导混合CaOx-/CaP-肾钙化症。该建议的一个新颖方面是，将使用离子色谱和偏光显微镜/安素染色+形态计量学分析来将草酸盐对肾单位、间质或脉管系统的特定部分的影响与肾内草酸盐浓度和晶体沉积联系起来。剂量反应和时间过程研究将确定在晶体沉积之前发生的变化，从而可能促进肾钙化症。在Specific Aim 1中，将确定360mmkox /24hr对14D的肝功能、心肌病和骨重塑的影响，并制定长剂量方案。Specific Aim 2将利用RT-PCR、Northern & Western blotting和免疫荧光来识别连续、稳定暴露于草酸盐期间，特定节段、一般窘迫、血管窘迫和结石疾病的表达变化。特异性目的3将利用透射电子显微镜和免疫荧光来识别在连续、稳定暴露于草酸盐中表现出形态学损伤、细胞凋亡或增殖的肾元片段和间质和血管区域。与公共卫生的相关性：本建议使用大鼠迷你泵模型研究草酸盐在CaOx-肾钙化症和草酸盐驱动的结石疾病早期阶段对肾脏特定区域的影响。我们的目标是找出导致这些情况的因素。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.