Citric acid or citrates in urine: which should we focus on in the prevention of calcium oxalate crystals and stones?
Citric acid or citrates in urine: which should we focus on in the prevention of calcium oxalate crystals and stones?
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尿液中的柠檬酸或柠檬酸盐：预防草酸钙结晶和结石应重点关注哪一个？
作者：
N. Laube;B. Jansen;A. Hesse
抽象。为了区分正常柠檬酸尿和低柠檬酸尿，根据2.5 mmol/天的既定限值评价柠檬酸的24 h尿液排泄值。我们建议将这种广泛使用的排泄值改为柠檬酸对总尿液离子强度的“最小贡献”，因为柠檬酸对结晶的抑制作用取决于柠檬酸盐阴离子可用于络合钙离子或与晶体表面缔合。对74例健康人和58例钙结石患者的714份24 h尿液样本进行了pH、柠檬酸浓度（[CA]）和相关的草酸钙过饱和度（RS）的研究。根据Henderson-Hasselbalch方程，根据尿液pH值和[CA]计算每种尿液中不同电荷柠檬酸盐阴离子物质的个体浓度。根据测定的阴离子浓度，计算尿液柠檬酸对总尿液离子强度ISCA的贡献。参考2.5 mmol/天的限值，并假设平均尿量为1.5 l/天，可获得1.67 mmol/l的假设浓度限值。将样本分为“结石形成者”和“非结石形成者”以及三个不同的RS范围，结果显示：（1）各组的[CA]-值中位数低于1.67 mmol/l，（2）[CA]与结石形成风险不呈负相关。在pH值为5至7的范围内，例如与[CA]=1.67 mmol/l相关的ISCA值在2.48 mmol/l至6.64 mmol/l之间变化很大，变化系数接近3。使用固定的柠檬酸排泄水平来区分正常柠檬酸尿症和低柠檬酸尿症，没有考虑实际上改变尿液结晶行为的不同柠檬酸盐种类。拟议的ISCA方法考虑到了这一事实。从这个参数，可以得到理想的“柠檬酸的最小影响”。在第一种方法中，潜在的ISCA极限值可以设定为2.48 mmol/l，该极限值目前区分由“正常保护”影响指示的尿液和由关于草酸钙沉淀的“低保护”影响指示的尿液。
Abstract. In order to distinguish between normocitraturia and hypocitraturia, the 24 h urine excretion value of citric acid is evaluated in relation to the established limit value of 2.5 mmol/day. We propose changing this widely-used excretion value to a "minimum contribution" of citric acid to the total urine's ionic strength, since the inhibitory effect of citric acid on crystallization depends on citrate anions being available to complex calcium ions or to associate with the crystal surface. A total of 714 24 h-urine samples, taken from 74 healthy persons and 58 calcium stone formers, were investigated for pH, citric acid concentration ([CA]), and related relative calcium oxalate supersaturation (RS). Based on the Henderson-Hasselbalch-equation, the individual concentrations of the differently charged citrate anion species in each of the urines were calculated from the urinary pH and [CA]. From the anion concentrations determined, the contribution of the urine's citric acid to the total urine's ionic strength, ISCA, was calculated. Referring to the limit value of 2.5 mmol/day and assuming an average urine volume of 1.5 l/day, a hypothetical concentration limit of 1.67 mmol/l can be obtained. Grouping the samples into "stone-formers" and "non-stone-formers" as well as into three different ranges of RS revealed: (1) that the groups' median [CA]-values were below 1.67 mmol/l, and (2) that [CA] was not inversely associated with the risk of stone formation. Within the pH-range of 5 and 7, the ISCA-values which are related to, for example, [CA]=1.67 mmol/l, vary considerably by a factor of nearly three between 2.48 mmol/l and 6.64 mmol/l. The use of a fixed citric acid excretion level for the distinction of normocitraturia from hypocitraturia does not take into account the different citrate species which actually modify the urine's crystallization behaviour. The proposed ISCA approach takes this fact into consideration. From this parameter, a desirable "minimum impact of citric acid" can be derived. In a first approach, a potential ISCA-limit value, which currently distinguishes between urines indicated by a "normo-protective" impact and those indicated by a "hypo-protective" impact with respect to calcium oxalate precipitation, may be set at 2.48 mmol/l.
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影响因子：
6.6
作者：
PREMINGER, GM;SAKHAEE, K;PAK, CYC
通讯作者：
PAK, CYC
影响因子：
19.6
作者：
Curhan, GC;Willett, WC;Stampfer, MJ
通讯作者：
Stampfer, MJ
蛋白激酶 C 介导的肾 Na(+)/二羧酸协同转运蛋白 NaDC-1 的调节。
DOI：
10.1016/s0005-2736(99)00102-9
发表时间：
1999
期刊：
Biochimica et biophysica acta
影响因子：
--
作者：
Pajor,AM;Sun,N
通讯作者：
Sun,N
肾结石尿柠檬酸排泄量低。
影响因子：
2.1
作者：
Nicar,MJ;Skurla,C;Sakhaee,K;Pak,CY
通讯作者：
Pak,CY