Gao Haoxue, Yu Xiaoyi, Sun Runbin, Yang Na, He Jun, Tao Mingxue, Gu Huilin, Yan Caixia, Aa Jiye, Wang Guangji
Laboratory of Metabolomics, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
Laboratory of Metabolomics, Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China.
J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Mar 1;1077-1078:28-34. doi: 10.1016/j.jchromb.2017.12.021. Epub 2018 Jan 31.
The early diagnosis of diabetic nephropathy (DN) is rather challenging. Our previous study suggested that citric acid is a potential marker for the early diagnosis of diabetic nephropathy in db/db mice. For the first time, in this study, a surrogate analyte of C-citric acid was employed to generate calibration curves for the quantitative measurement of the endogenous citric acid in the sera of db/db mice and diabetic nephropathy patients by GC/MS after the analytes were extracted, methoximated and trimethylsilylated. The constant response factor of C-citric acid versus citric acid over the linear range indicated the identical ionization efficiency of these two compounds. The full validation assessments suggested that the method is sensitive, specific, reliable, reproducible and has acceptable parameters. Statistical analysis revealed cut-off citric acid concentrations of 29.24 μg/mL with a 95% confidence interval between 32.75 and 39.16 μg/mL in the diabetic nephropathy patients and 16.74 and 22.57 μg/mL in the normal controls. The areas under the receiver operating characteristic curves indicated accuracies of over 90% for the diagnoses of early diabetic nephropathy in both humans and db/db mice, which suggests that the serum citric acid level is potentially a biomarker that could assist in the diagnosis of diabetic nephropathy.
糖尿病肾病（DN）的早期诊断颇具挑战性。我们之前的研究表明，柠檬酸是db/db小鼠糖尿病肾病早期诊断的潜在标志物。在本研究中，首次使用C-柠檬酸的替代分析物，在分析物经提取、甲氧胺化和三甲基硅烷化后，通过气相色谱/质谱法（GC/MS）生成校准曲线，用于定量测量db/db小鼠和糖尿病肾病患者血清中的内源性柠檬酸。C-柠檬酸与柠檬酸在线性范围内的恒定响应因子表明这两种化合物具有相同的电离效率。全面的验证评估表明该方法灵敏、特异、可靠、可重复且具有可接受的参数。统计分析显示，糖尿病肾病患者的柠檬酸截止浓度为29.24μg/mL，95%置信区间为32.75至39.16μg/mL，正常对照组为16.74至22.57μg/mL。受试者工作特征曲线下面积表明，该方法对人类和db/db小鼠早期糖尿病肾病诊断的准确率均超过90%，这表明血清柠檬酸水平可能是有助于糖尿病肾病诊断的生物标志物。
