Supplementary Material for: FABP1 and FABP3 Have High Predictive Values for Renal Replacement Therapy in Patients with Acute Kidney Injury

<b><i>Background/Aims:</i></b> Early initiation of renal replacement therapy (RRT) is recommended in order to improve the clinical outcome of patients who develop an acute kidney injury (AKI). However, markers that guide an early RRT initiation do not really exist currently. <b><i>Methods:</i></b> Urine and serum samples were prospectively collected from 120 AKI patients. Depending on the necessity of initiating RRT, patients were divided into 2 different groups: dialysis (n = 52) and non-dialysis (n = 68). <b><i>Results:</i></b> Comparative urinary proteomic analyses identified 4 different proteins (fatty acid binding proteins 1 and 3 (FABP1 and FABP3), β-2-microglobulin (B2M), cystatin-M (CST6)) that discriminate AKI patients with high risk for RRT. Western blot analysis confirmed the proteomics data for FABP1 and FABP3 but not for B2M and CST6. Validation analysis confirmed that the FABP1 and FABP3 fulfilled the requirement of functioning as markers for AKI patients with risk to dialysis (p &lt; 0.001). <b><i>Conclusion:</i></b> The release of high amounts of FABP1 and FABP3 in urine of AKI patients could serve as a diagnostic/prognosis marker for RRT initiation in these patients.

**背景与目的**：目前推荐早期启动肾替代治疗（renal replacement therapy, RRT）以改善急性肾损伤（acute kidney injury, AKI）患者的临床结局，但当前尚无用于指导早期RRT启动的特异性标志物。
**方法**：本研究前瞻性采集了120例AKI患者的尿液与血清样本。根据是否需要启动RRT，将患者分为透析组（n=52）与非透析组（n=68）。
**结果**：对比尿液蛋白质组学分析筛选出4种可区分高RRT启动风险AKI患者的差异蛋白，分别为脂肪酸结合蛋白1、3（fatty acid binding proteins 1 and 3, FABP1、FABP3）、β-2-微球蛋白（β-2-microglobulin, B2M）以及胱抑素M（cystatin-M, CST6）。蛋白质免疫印迹（Western blot）验证结果显示，FABP1与FABP3的表达趋势与蛋白质组学分析结果一致，但B2M与CST6未得到验证。后续验证分析证实，FABP1与FABP3可作为AKI患者透析风险的有效标志物（p<0.001）。
**结论**：AKI患者尿液中高水平表达的FABP1与FABP3，可作为此类患者启动RRT的诊断/预后标志物。