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蔡雷鸣, 厉倩, 金才峰, 谭龙益, 廖敏蕾, 鲍洁. 血清中性粒细胞明胶酶相关脂质运载蛋白检测在急性肾功能损伤早期诊断中的临床意义. 2012, 27(4): 287-290
CAI Leiming, LI Qian, JIN Caifeng, TAN Longyi, LIAO Minlei, BAO Jie. Clinical significance of serum neutrophil gelatinase-associated lipocalin detection in early diagnosis of acute kidney injury. Labratory Medicine, 2012, 27(4): 287-290  
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Copyright©2012, 《检验医学》编辑部
《检验医学》编辑部
血清中性粒细胞明胶酶相关脂质运载蛋白检测在急性肾功能损伤早期诊断中的临床意义
蔡雷鸣1, 厉倩1, 金才峰1, 谭龙益1, 廖敏蕾2, 鲍洁2
1.上海市第一人民医院宝山分院检验科,上海 200940
2.上海市第一人民医院宝山分院心内科,上海 200940

作者简介：蔡雷鸣,男,1980年生,技师,主要从事临床检验工作。

基金:上海市宝山区科委课题资助项目（08E23）
摘要

目的 探讨血清中性粒细胞明胶酶相关脂质运载蛋白(NGAL)检测在急性肾功能损伤(AKI)早期诊断中的意义。方法 收集无慢性肾病的重症监护病房(ICU)、冠心病监护病房(CCU)患者60例,分别在其术前及术后6、12、48 h采集血样,其中27例发生AKI(AKI组),以其余33例未发生AKI(无AKI组)。应用酶联免疫吸附试验(ELISA)检测血清NGAL浓度,碱性苦味酸法检测血清肌酐(SCr)浓度,胶乳增强免疫浊度法检测血清半胱氨酸蛋白酶抑制剂C(Cys C)浓度。以48 h内SCr高于基础水平50%作为AKI的诊断标准,应用受试者工作特征(ROC)曲线评估NGAL在AKI早期诊断中的效力。结果 与术前比较,AKI组术后6、12、48 h的血清NGAL明显升高,Cys C在术后12、48 h明显升高,而SCr在术后48 h才显著升高。无AKI组术前与术后6、12、48 h的NGAL、SCr、Cys C浓度差异无统计学意义( P>0.05)。术后6、12、48 h血清NGAL的ROC曲线下面积为0.51[95%可信区间( CI): 0.250.78]、0.80(95% CI: 0.580.95)、0.85(95% CI: 0.610.99)。结论 血清NGAL在术后6 h上升,术后12 h即能较好地预测AKI,其预测AKI时间早于Cys C和SCr。血清NGAL可能在AKI早期诊断中有良好的应用价值。

关键词: 中性粒细胞明胶酶相关脂质运载蛋白; 半胱氨酸蛋白酶抑制剂C; 肌酐; 急性肾功能损伤
中图分类号:R446.11 文献标志码:A 文章编号:1673-8640(2012)04-0287-04
Clinical significance of serum neutrophil gelatinase-associated lipocalin detection in early diagnosis of acute kidney injury
CAI Leiming1, LI Qian1, JIN Caifeng2, TAN Longyi1, LIAO Minlei2, BAO Jie2
1.Department of Clinical Laboratory, Baoshan Branch,Shanghai First People's Hospital, Shanghai 200940, China
2.Department of Cardiology, Baoshan Branch,Shanghai First People's Hospital, Shanghai 200940, China
Abstract

Objective To investigate the clinical significance of serum neutrophil gelatinase-associated lipocalin(NGAL) detection in early diagnosis of acute kidney injury(AKI).Methods A total of 60 inpatients in intensive care unit (ICU) and coronary care unit (CCU) without chronic kidney diseases were enrolled. Sera were collected before surgery and 6, 12 and 48 h after surgery respectively. There were 27 AKI patients and other 33 patients without AKI. The concentration of NGAL was determined by enzyme-linked immunosorbent assay (ELISA). Serum creatinine (SCr) was detected by Jaffé reaction method. Serum cystatin C (Cys C) was detected by Latex-enhanced immunoturbidimetry. AKI was defined as an increase in SCr of at least 50% from baseline within 48 h. The efficiency of NGAL in early diagnosis of AKI was evaluated by receiver operating characteristic (ROC) curve.Results Serum NGAL increased significantly 6, 12 and 48 h after surgery, while serum Cys C increased 12 and 48 h after surgery, and SCr increased 48 h after surgery in the AKI group. There was no obvious difference in the concentrations of NGAL, SCr and Cys C in the non-AKI group before and 6, 12 and 48 h after surgery ( P>0.05). By ROC curve analysis, serum NGAL 6 h after surgery had an area under the curve of 0.51 [95% confidence interval ( CI): 0.25-0.78], serum NGAL 12 h after surgery had an area under the curve of 0.80 (95% CI: 0.58-0.95), and serum NGAL 48 h after surgery had an area under the curve of 0.85 (95% CI: 0.61-0.99).Conclusions Serum NGAL increases 6 h after surgery and predicts AKI accurately 12 h after surgery. For predicting AKI, serum NGAL is earlier than Cys C and SCr, and shows that serum NGAL can be as potential marker for the early diagnosis of AKI.

Keyword: Neutrophil gelatinase-associated lipocalin; Cystatin C; Creatinine; Acute kidney injury

急性肾功能损伤(acute kidney injure, AKI)是临床多发且病死率较高的疾病, 主要原因是缺乏早期、敏感、特异的诊断手段。临床现在用来判断AKI主要还是依靠血清肌酐(SCr)的检测[1]。但是肾脏有很强的代偿能力, 通常SCr的升高是出现在病程的中、晚期, 延误治疗时机[2]。最近的研究发现中性粒细胞明胶酶相关脂质运载蛋白(neutrophil gelatinase-associated lipocalin, NGAL)与AKI有极高的相关性[3], 可能对AKI早期诊断、预防、治疗和预后改善等方面有重要意义。我们主要探讨了血清NGAL在AKI早期诊断中的价值。

材料和方法
一、研究对象

收集2009年1月至2010年12月上海市第一人民医院宝山分院无慢性肾病的重症监护病房(ICU)、冠心病监护病房(CCU)患者60例, ICU中的患者主要是外科大手术、多发性挤压伤患者, CCU的患者主要是造影剂介入手术者。AKI根据2007年制定的急性肾功能损伤小组(acute kidney injury network, AKIN)标准确诊, 60例患者有27例发生了AKI(AKI组), AKI发生率为45%, 其余33例列入无AKI组。分别在术前及术后6、12、48 h采集外周静脉血35 mL, 离心制备血清于-80 ℃冰冻备用。

二、检测方法

NGAL检测采用酶联免疫吸附试验(ELISA), 试剂盒由丹麦bioporto公司提供, 仪器为BIO-TEK全自动酶标仪; SCr检测采用碱性苦味酸法, 试剂由美国Beckman-Coulter公司提供; 半胱氨酸蛋白酶抑制剂C (Cys C)检测采用胶乳增强免疫浊度法, 试剂由上海申索佑福生物有限公司提供; 仪器为Beckman Lx-20全自动生化仪。AKI诊断标准为48 h内SCr高于基础水平50%[1]。各项检测严格按照标准操作规程操作。

三、统计学方法

采用SPSS 16.0软件进行分析, 所有计量资料以 x-± s表示, 计量资料比较用t检验, P< 0.05表示差异有统计学意义。用受试者工作特征(ROC)曲线及曲线下面积评价NGAL的诊断效率。

结 果

无AKI组术前与术后6、12、48 h的NGAL、SCr、Cys C浓度无明显变化(P> 0.05)。AKI组术后6、12、48 h的NGAL浓度均明显高于术前(P< 0.05)。AKI组术后12、48 h的Cys C浓度明显高于术前(P< 0.05), 而术后6 h与术前比较差异无统计学意义(P> 0.05)。AKI组术后48 h的SCr浓度明显高于术前(P< 0.05), 而术后6、12 h SCr浓度与术前相比差异无统计学意义(P> 0.05)。见表1。

进一步用ROC曲线分析发现, 术后6、12和48 h血清NGAL的ROC曲线下面积分别为0.51[95%可信区间(CI):0.250.78]、0.80(95%CI:0.580.95)、0.85(95%CI:0.610.99), 见图1。当术后12 h的血清NGAL诊断值设为200 ng/mL时, 其诊断AKI的敏感性和特异性分别为91.7%、77.8%。

表1 各组NGAL、Cys C、SCr不同时间段的平均浓度

图1 术后12 h血清NGAL在AKI诊断中的ROC曲线

讨 论

AKI是病死率的独立预测因子。在现阶段, SCr和尿量是国际公认的AKI诊断和分期标准[1]。但SCr并非一个敏感指标, 而且从SCr代谢与分布的生理学来看, SCr除反映肾小球滤过率(glomerulus filtration rate, GFR)外, 还受到其分布及排泌等综合作用的影响。目前比较一致的观点认为, SCr因易受年龄、体重、性别、种族、营养状态、蛋白摄入量等许多非肾脏因素的影响, 敏感性差。尿量更易受到血容量状态、药物等非肾脏因素影响[2]。因此, 一旦GFR下降、SCr上升, 肾功能损害往往已达到相当严重的程度。AKI诊断亟待更敏感的早期诊断指标。

NGAL是1993年在动物中性粒细胞中发现的与明胶酶结合的分泌型蛋白质, 相对分子质量为25 000, 属于脂质运载蛋白家族中成员[4]。在生理状态下, 中性粒细胞、肾小管上皮细胞、肺泡巨噬细胞、支气管上皮黏液细胞、胃壁细胞、小肠潘氏细胞、肝胆管细胞、胰腺细胞等分泌少量NGAL, 循环NGAL通过肾小球滤过, 在近端肾小管重吸收[5]。研究人员通过缺血性及肾毒性损伤动物模型发现, 在损伤发生后2 h内肾小管上皮细胞NGAL的转录表达有显著升高[6, 7, 8]。大量后续的临床研究也证实了动物实验的结果, 血液和尿液NGAL在不同年龄、不同疾病患者中都具有较好的AKI预测价值[9, 10, 11, 12, 13, 14]。

本项目研究对象为住院患者中AKI相对高发的ICU和CCU患者, 这些患者接受外科手术或放射造影剂的暴露有比较高的AKI发生概率, 并剔除了术前SCr异常的病例。因为慢性肾病患者的NGAL平均水平比较高[15], 本研究AKI的发生率为45%(27/60), 这与文献[14]报道的基本一致。本研究选择了术前及术后6、12、48 h共4个时间节点观察血清NGAL的变化规律, 发现血清NGAL在术后6 h开始升高, 术后12 h的血清NGAL能较准确地预测AKI的发生, 诊断值为200 ng/mL时, 诊断AKI的敏感性和特异性分别为91.7%和77.8%, 比目前公认的AKI标志物SCr和新的标志物Cys C的升高和预测时间更早。

由于受条件限制, 本研究没有检测尿液NGAL的变化规律, 多项研究表明尿液NGAL也能较好地预测AKI的发生。联合检测血和尿液NGAL的变化规律可能更好地预测AKI的发生。有文献报道, 正常人血NGAL浓度为5090 ng/mL[14], 尿NGAL浓度很低(< 5 ng/mL)[9], 本研究中无AKI组的血NGAL浓度为120130 ng/mL, 比文献报道的正常人高, 这可能是住院患者受到药物、疾病等多项干扰因素影响导致。

有研究表明血清NGAL的浓度高低能反映肾功能的受损程度[14, 16, 17], 本研究由于病例数不多, 没有做NGAL浓度与肾功能变化的相关性分析, 如果能进一步延长观察时间和收集更多病例, 对患者整个住院期间的肾功能进行跟踪, 将对进一步阐明NGAL在AKI中的临床意义有重要作用。

总之, 血清NGAL在术后6 h上升, 术后12 h即能较好地预测AKI, 其预测AKI时间早于SCr和血清Cys C, 这表明血清NGAL可能在AKI早期诊断中有良好的应用价值。

The authors have declared that no competing interests exist.

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