Department of Nephrology and Hypertension, Internal Medicine, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-Ku, Kawasaki, Kanagawa 216-8511, Japan.
Clin Exp Nephrol. 2011 Apr;15(2):220-5. doi: 10.1007/s10157-010-0384-y. Epub 2010 Dec 14.
Acute kidney injury (AKI) is a common complication in critically ill patients. Urinary excretion of liver-type fatty acid-binding protein (L-FABP), which is expressed in the proximal tubules, reflects the presence of tubular injury. Urinary excretion of podocalyxin (PCX), a glycoprotein prominently expressed on podocytes, is associated with podocyte injury. Our aims were to evaluate the utility of urinary L-FABP for the early detection of AKI and to examine whether podocyte injury is present in AKI patients using the biomarker of urinary PCX.
Patients admitted to the intensive care unit (ICU) were divided into the AKI group (n = 14) and non-AKI group (n = 11), according to the occurrence of AKI during hospitalization in the ICU. Changes in various biomarkers were evaluated.
In the AKI group, elevation of urinary L-FABP level [maximum value of L-FABP, 199.0 (92.5-433.6) μg/g creatinine, median (25-75% interquartile range)], which reflects tubular injury (area under the curve 0.95, cut-off value 44.1 μg/g Cr), occurred between -30 and 0 h before the occurrence of AKI (i.e., the time at which serum creatinine peaked), and elevation of urinary PCX level [maximum value of PCX, 389.5 (267.0-501.0) μg/g creatinine; upper limit of reference value, 160 μg/g creatinine] occurred during the time of recovery from AKI when serum creatinine levels were decreasing between 34.0 and 72.0 h after the occurrence of AKI. Furthermore, a parameter with the primary large AUC for predicting the onset of AKI was urinary L-FABP.
Our study suggests that L-FABP is a useful biomarker for early detection of AKI and that podocyte injury was induced during the recovery phase of AKI.
急性肾损伤（AKI）是危重病患者的常见并发症。肝脏型脂肪酸结合蛋白（L-FABP）在近端肾小管中表达，其尿排泄反映了肾小管损伤的存在。足细胞上显著表达的糖蛋白足突蛋白（PCX）的尿排泄与足细胞损伤有关。我们的目的是评估尿 L-FABP 对 AKI 的早期检测的效用，并通过尿 PCX 生物标志物检查 AKI 患者是否存在足细胞损伤。
根据 ICU 住院期间 AKI 的发生情况，将入住 ICU 的患者分为 AKI 组（n=14）和非 AKI 组（n=11）。评估了各种生物标志物的变化。
在 AKI 组中，尿 L-FABP 水平升高[L-FABP 的最高值，199.0（92.5-433.6）μg/g 肌酐，中位数（25-75% 四分位数范围）]，反映了肾小管损伤（曲线下面积 0.95，临界值 44.1μg/g Cr），发生在 AKI 发生前 -30 至 0 小时（即血清肌酐峰值时），尿 PCX 水平升高[PCX 的最高值，389.5（267.0-501.0）μg/g 肌酐；参考值上限 160μg/g 肌酐]发生在 AKI 恢复期间，此时血清肌酐水平在 AKI 发生后 34.0 至 72.0 小时之间下降。此外，用于预测 AKI 发生的具有主要大 AUC 的参数是尿 L-FABP。
我们的研究表明，L-FABP 是 AKI 早期检测的有用生物标志物，并且在 AKI 的恢复阶段诱导了足细胞损伤。
