Cystinuria, a rare inherited aminoaciduria condition, is characterized by the hyperexcretion of cystine, ornithine, lysine, and arginine. Its main clinical manifestation is cystine stone formation in the urinary tract, being responsible for 1–2% total and 6–8% pediatric lithiasis. Cystinuria patients suffer from recurrent lithiasic episodes that might end in surgical interventions, progressive renal functional deterioration, and kidney loss. Cystinuria is monitored for the presence of urinary cystine stones by crystalluria, imaging techniques or urinary cystine capacity; all with limited predicting capabilities. We analyzed blood and urine levels of the natural antioxidant L-ergothioneine in a Type B cystinuria mouse model, and urine levels of its metabolic product S-methyl-L-ergothioneine, in both male and female mice at two different ages and with different lithiasic phenotype. Urinary levels of S-methyl-L-ergothioneine showed differences related to age, gender and lithiasic phenotype. Once normalized by L-ergothioneine to account for interindividual differences, the S-methyl-L-ergothioneine to L-ergothioneine urinary ratio discriminated between cystine lithiasic phenotypes. Urine S-methyl-L-ergothioneine to L-ergothioneine ratio could be easily determined in urine and, as being capable of discriminating between cystine lithiasis phenotypes, it could be used as a lithiasis biomarker in cystinuria patient management.

中文翻译：

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尿液中 S-甲基-L-麦角硫因与 L-麦角硫因的比率是胱氨酸尿症小鼠模型中胱氨酸结石症的标志物

胱氨酸尿症是一种罕见的遗传性氨基酸尿症，其特征是胱氨酸、鸟氨酸、赖氨酸和精氨酸的过度排泄。其主要临床表现是泌尿道胱氨酸结石形成，占总结石的 1-2% 和 6-8% 的小儿结石。胱氨酸尿症患者患有可能以手术干预、进行性肾功能恶化和肾丢失而告终的复发性结石发作。通过结晶尿、成像技术或尿胱氨酸容量监测胱氨酸尿中是否存在尿胱氨酸结石；所有这些都具有有限的预测能力。我们分析了 B 型胱氨酸尿症小鼠模型中天然抗氧化剂 L-麦角硫因的血液和尿液水平，以及其代谢产物 S-甲基-L-麦角硫因的尿液水平，在两个不同年龄和不同结石表型的雄性和雌性小鼠中。S-甲基-L-麦角硫因的尿液水平显示出与年龄、性别和结石表型相关的差异。一旦被 L-麦角硫因标准化以解释个体差异，S-甲基-L-麦角硫因与 L-麦角硫因的尿比率就可以区分胱氨酸结石表型。尿液中 S-甲基-L-麦角硫因与 L-麦角硫因的比率可以很容易地在尿液中确定，并且由于能够区分胱氨酸结石表型，它可以用作胱氨酸尿症患者管理中的结石生物标志物。一旦被 L-麦角硫因标准化以解释个体差异，S-甲基-L-麦角硫因与 L-麦角硫因的尿比率就可以区分胱氨酸结石表型。尿液中 S-甲基-L-麦角硫因与 L-麦角硫因的比率可以很容易地在尿液中确定，并且由于能够区分胱氨酸结石表型，它可以用作胱氨酸尿症患者管理中的结石生物标志物。一旦被 L-麦角硫因标准化以解释个体差异，S-甲基-L-麦角硫因与 L-麦角硫因的尿比率就可以区分胱氨酸结石表型。尿液中 S-甲基-L-麦角硫因与 L-麦角硫因的比率可以很容易地在尿液中确定，并且由于能够区分胱氨酸结石表型，它可以用作胱氨酸尿症患者管理中的结石生物标志物。