CALCIUM-OXALATE INTERATION IN MODULATING CALCIUM OXALATE STONE FORMATION

草酸钙相互作用调节草酸钙结石的形成

• 批准号: 7333201
• 负责人: MARGARET S. PEARLE
• 金额: $ 6.46万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7333201
• 关键词: Affect; Attenuated; Binding; Calcium; Calcium Carbonate; Calcium Citrate; Calcium Oxalate; Calculi; Citrate; Citrates; Complex; Confounding Factors (Epidemiology); Cross-Over Studies; Data; Dependence; Diet; Dietary Calcium; Evaluation; Food; Hour; Individual; Ingestion; Intake; Intestinal Absorption; Intestines; Liquid substance; Magnesium; Metabolic; Nutrient; Oxalates; Patients; Phase; Placebos; Play; Potassium; Process; Randomized; Role; Specimen; Supplementation; Testing; Urine; absorption; day; dietary restriction; falls; gluconate; hypercalciuria; patient registry; programs; urinary

The objective of this component is to elucidate the "calcium-oxalate interaction", a process by which dietary calcium affects urinary oxalate by binding oxalate in the intestine, reducing the amount of absorbed oxalate, and by reducing urinary ionic oxalate through complexation. The overall hypothesis is that calcium-oxalate interaction is dependent on dietary oxalate, the state of intestinal calcium absorption and on the delivery of calcium as food or supplement. In Aim 1, our objective is to demonstrate that for normal subjects calcium-oxalate interaction occurs during a liberal, but not restricted oxalate intake. Our hypothesis is that the decline in urinary oxalate will oppose the rise in urinary calcium associated with calcium supplementation, minimizing the change in urinary saturation of calcium oxalate. In this 2-phase randomized crossover trial comprised of placebo and calcium carbonate phases, 10 normal subjects maintained on a metabolic diet will collect two 24-hour urine specimens on the last 2 days of each phase. In Aim 2, our objective is to demonstrate that calcium-oxalate interaction is exaggerated in states of absorptive hypercalciuria (AH) compared with normal intestinal calcium absorption. In a 2-phase randomized crossover trial, we will test the effect of calcium carbonate supplementation versus placebo during oxalate restriction in 16 AH patients on a metabolic diet. We expect a modest but significant increase in urinary saturation of calcium oxalate, to a lesser degree than seen in normal subjects. In Aim 3, our objective is to show that calcium delivered as food promotes less calcium-oxalate interaction than calcium delivered as a supplement due to the interaction of potentially protective nutrients in food. From a 2-phase randomized crossover study conducted in 10 normal subjects maintained on a low or a high calcium diet with a liberal oxalate intake, we expect an attenuated rise in urinary saturation of calcium oxalate during a high calcium diet due to a decline in urinary oxalate. In Aim 4, we test the hypothesis that saturation of calcium oxalate is dependent on urinary calcium concentration when oxalate isrestricted. Using data from a registry of patients who completed an ambulatory evaluation, the urinary RSR of calcium oxalate derived from 24-hour urines collected on random and restricted diets will be calculated and correlated with corresponding urinary calcium and oxalate concentrations in AH-I, AH-II and normocalciuric patient groups.

该成分的目的是阐明“钙-草酸盐相互作用”，即膳食钙通过在肠道中结合草酸盐、减少吸收的草酸盐量以及通过络合减少尿离子草酸盐来影响尿草酸盐的过程。总体假设是，钙-草酸相互作用取决于膳食草酸盐、肠道钙吸收状态以及钙作为食物或补充剂的输送。 在目标 1 中，我们的目标是证明对于正常受试者，草酸钙相互作用发生在自由但不限制草酸盐摄入期间。我们的假设是，尿草酸的下降将与补钙相关的尿钙的上升相反，从而最大限度地减少尿草酸钙饱和度的变化。在这项由安慰剂阶段和碳酸钙阶段组成的两阶段随机交叉试验中，10 名维持代谢饮食的正常受试者将在每个阶段的最后 2 天收集两份 24 小时尿液样本。在目标 2 中，我们的目标是证明与正常肠道钙吸收相比，吸收性高钙尿症 (AH) 状态下钙与草酸的相互作用更加严重。在一项两阶段随机交叉试验中，我们将测试 16 名采用代谢饮食的 AH 患者在限制草酸期间补充碳酸钙与安慰剂的效果。我们预计尿草酸钙饱和度会适度但显着增加，其程度低于正常受试者中所见的程度。在目标 3 中，我们的目标是证明，由于食物中潜在保护性营养素的相互作用，以食物形式提供的钙比以补充剂形式提供的钙促进更少的钙-草酸相互作用。根据对 10 名保持低钙或高钙饮食且摄入大量草酸盐的正常受试者进行的两阶段随机交叉研究，我们预计，在高钙饮食期间，由于尿草酸盐下降，尿草酸钙饱和度的上升会减弱。在目标 4 中，我们检验了以下假设：当草酸盐受到限制时，草酸钙的饱和度取决于尿钙浓度。使用完成门诊评估的患者登记数据，将计算随机和限制饮食收集的 24 小时尿液中草酸钙的尿 RSR，并将其与 AH-I、AH-II 和正常尿钙患者组中相应的尿钙和草酸盐浓度相关联。