中性粒细胞明胶酶相关脂质运载蛋白：早期诊断成人心脏术后急性肾损伤的生物学指标（英文）

心脏术后急性肾损伤的出现会增加患者的死亡率,需要寻找早期诊断急性肾损伤的生物学指标。中性粒细胞明胶酶相关脂质运载蛋白似乎是早期诊断急性肾损伤的生物学指标,它是否能够早期诊断急性肾损伤已经做了广泛的报道。本文综述了已有研究证明它是否能够早期诊断急性     

尿液NGAL作为药物诱导急性肾毒性生物标志物的研究进展

寻找能早期、灵敏、特异地诊断肾毒性的新型生物标志物已成为目前药物临床前研究的热点。大量研究发现尿液中性粒细胞明胶酶相关脂质运载蛋白（NGAL）对肾损伤的诊断效能优于传统生物标志物血清肌酐和尿素氮。2018年尿液NGAL获得了美国食品药品监督管理局的批准，可用于I期临床试验中药物对肾小管损伤作用的监测，但其在临床前试验中的应用和推广仍有待进一步研究。就NGAL特性、作为药物诱导急性肾损伤生物标志物研究进展及其应用面临的挑战进行综述，以期为NGAL在我国新药研发中对急性肾毒性评价的应用奠定基础。     

NGAL is a precocious marker of therapeutic response

NGAL (Neutrophil Gelatinase-Associated Lipocalin) is a small 25-kD peptide belonging to the lipocalin superfamily. Several studies highlight its role as an organ injury and disease activity biomarker. In the present review, instead, we wanted to study NGAL as a precocious marker of therapeutic response in renal and non-renal diseases (glomerulonephritis, vasculitis, LES, Crohn's disease and other chronic inflammatory pathologies). The obtained outcomes support the hypothesis that NGAL could be employed as a biomarker of response to different therapeutic schemes, because its levels sensibly and precociously change compared to other haematologic and biochemical parameters.     

Lipocalin‐2—The myth of its expression and function

Lipocalin‐2 is a functional biomarker for acute and chronic kidney diseases, heart failure and obesity‐related medical complications. It is rapidly induced in epithelial cells under stress conditions, but constitutively produced from pre‐adipocytes and mature adipocytes. Measuring the lipocalin‐2 levels represents an effective approach for risk prediction, patient stratification and disease management. Nevertheless, due to ligand‐binding, post‐translational modification and protein‐protein interaction, lipocalin‐2 exists as multiple variants that elicit different pathophysiological functions. To characterize the specific structure‐functional relationships of lipocalin‐2 variants is critical for the development of biomarker assays with sufficient precision and reliability. Moreover, identifying the pathological forms of lipocalin‐2 will provide new therapeutic targets and treatment approaches for obesity‐related complications.     

检测中性粒细胞明胶酶脂质运载蛋白早期诊断体外循环术后急性肾损伤

目的探讨中性粒细胞明胶酶脂质运载蛋白(neutrophil gelatinase-associated lipocalin,NGAL)在体外循环术后急性肾损伤(acute kidney injury,AKI)早期诊断中应用。方法选择120例进行体外循环手术的先天性心脏病患者,体外循环结束后第一个12 h内采集尿样及血样1次/2 h,此后3 d内采集1次/12 h,采用ELISA方法对尿样中NGAL进行定量分析,同时测定血清肌酐基线水平,并在术后相应时间点检测血清肌酐水平,血清肌酐比基线水平增加50%以上为发生AKI的标准。结果术后3 d内有21例发生不同程度AKI,发生率17.5%,AKI组在体外循环术后各时间点尿NAGL浓度都显著升高,以术后2~6 h最为显著,两组比较有显著性差异,对术后2 h的尿NAGL浓度在界限值为100μg/L时进行ROC分析,尿NAGL在AKI诊断中的敏感性和特异性分别为96%和93%。结论尿NAGL可以作为体外循环术后AKI的预测指标,在诊断AKI时较血清肌酐早,有利于早期对AKI进行预防和干预。     

Influence of renal ischaemia‐reperfusion injury on renal neutrophil gelatinase‐associated lipocalin receptor (24p3R) in rats

The neutrophil gelatinase‐associated lipocalin (NGAL) receptor (24p3R) is expressed in distal nephron and contributes to the endocytosis of NGAL in urine. This study was undertaken to evaluate an influence of renal ischaemia‐reperfusion injury on 24p3R. Unilateral renal pedicle was clamped for 0, 10, 20, 30, or 45 minutes in male Wistar rats. Urine was collected for 24 hours after reperfusion, and ischaemic kidney and blood sample were obtained. Apparent histological injury in the ischaemic kidney was detected in the 30 and 45 minutes‐treated groups. Urinary NGAL excretion elevated in rats with renal ischaemia for more than 20 minutes, while serum creatinine increased in rats for more than 30 minutes of ischaemia. Renal protein expression of NGAL did not significantly change. Renal mRNA expressions of megalin and cubilin, which are expressed at renal proximal tubules and uptake NGAL, decreased in animals with renal ischaemia for more than 20 minutes. Renal protein expression of 24p3R, which is expressed at renal distal tubules and uptake NGAL, decreased in rats with renal ischaemia for 45 min. This study showed for the first time that renal 24p3R decreased in response to renal ischaemia. As relatively longer renal ischaemia (45 minutes) decreased renal 24p3R protein and increased urinary NGAL excretion, the down‐regulation of 24p3R protein might contribute to the elevated urinary excretion of NGAL in rats with unilateral ischaemia‐reperfusion injury.     

Evaluation of the usefulness of novel biomarkers for drug-induced acute kidney injury in beagle dogs

As kidney is a major target organ affected by drug toxicity, early detection of renal injury is critical in preclinical drug development. In past decades, a series of novel biomarkers of drug-induced nephrotoxicity were discovered and verified in rats. However, limited data regarding the performance of novel biomarkers in non-rodent species are publicly available. To increase the applicability of these biomarkers, we evaluated the performance of 4 urinary biomarkers including neutrophil gelatinase-associated lipocalin (NGAL), clusterin, total protein, and N-acetyl-β-D-glucosaminidase (NAG), relative to histopathology and traditional clinical chemistry in beagle dogs with acute kidney injury (AKI) induced by gentamicin. The results showed that urinary NGAL and clusterin levels were significantly elevated in dogs on days 1 and 3 after administration of gentamicin, respectively. Gene expression analysis further provided mechanistic evidence to support that NGAL and clusterin are potential biomarkers for the early assessment of drug-induced renal damage. Furthermore, the high area (both AUCs = 1.000) under receiver operator characteristics (ROC) curve also indicated that NGAL and clusterin were the most sensitive biomarkers for detection of gentamicin-induced renal proximal tubular toxicity. Our results also suggested that NAG may be used in routine toxicity testing due to its sensitivity and robustness for detection of tissue injury. The present data will provide insights into the preclinical use of these biomarkers for detection of drug-induced AKI in non-rodent species.     

Neutrophil Gelatinase–Associated Lipocalin Acts as a Robust Early Diagnostic Marker for Renal Replacement Therapy in Patients with Russell’s Viper Bite–Induced Acute Kidney Injuries

Snakebite-induced acute kidney injury (AKI) is frequently observed in patients following bites from vipers such as Russell’s viper (Daboia russelii) in India. Currently, the levels of serum creatinine are mainly used as a marker to determine the necessity for renal replacement therapy (RRT) (haemodialysis) in severe cases of AKI. However, it takes up to 48 h to ascertain a distinct change in creatinine levels compared to its baseline level upon admission. The time lost between admission and the 48 h timepoint significantly affects the clinical management of snakebite victims. Moreover, early diagnosis of AKI and decision on the necessity for RRT in snakebite victims is critical in saving lives, reducing long-term complications, and minimising treatment costs arising from expensive haemodialysis. Neutrophil gelatinase–associated lipocalin (NGAL) has been recently studied as a robust early marker for AKI in non-snakebite patients. However, its suitability for clinical use in snakebite victims has not been rigorously established. Here, we demonstrate the clinical significance of plasma NGAL as a robust marker for RRT following AKI using a large cohort (309) of Russell’s viper victims without any pre-existing health conditions. NGAL levels upon admission are positively correlated with creatinine levels at 48 h in different stages of AKI. Overall, NGAL acts as a robust early marker to ascertain the need for RRT following Russell’s viper bites. The quantification of NGAL can be recommended as a routine test in hospitals that treat snakebites to decide on RRT at early time points instead of waiting for 48 h to confirm the increase in creatinine levels. The diagnostic use of NGAL in Russell’s viper victims with pre-existing comorbidities and for other vipers should be evaluated in future studies.     

Gene expression of biomarkers of nephrotoxicity in F344 rats co-exposed to melamine and cyanuric acid for seven days

A number of studies have demonstrated that co-exposure to low levels of melamine and cyanuric acid elicits renal toxicity due to the formation of melamine cyanurate crystals in the kidney nephrons. In this work, we investigated if co-exposure of rats to these compounds leads to alterations in the expression of the genes encoding kidney injury molecule 1 (KIM-1), metallopeptidase inhibitor 1 (TIMP1), clusterin, osteopontin, and neutrophil gelatinase-associated lipocalin/lipocalin 2 (NGAL), which have been proposed as urinary biomarkers for nephrotoxicity. Six-week-old male and female F344 rats were fed ad libitum a diet fortified with 0 (control), 7, 23, 69, 229, or 694 ppm melamine and cyanuric acid (co-exposure groups), 1388 ppm melamine, or 1388 ppm cyanuric acid for seven days. Histopathology and clinical chemistry examination indicated marked toxicity only in the animals exposed to the two highest combined doses of melamine and cyanuric acid. Consistent with these observations, quantitative real-time polymerase chain reaction analysis of kidney tissue indicated increased expression of all genes analyzed relative to the control in both male and female rats fed daily with 229 or 694 ppm melamine and cyanuric acid. Exposure to lower levels of both compounds or to the individual compounds did not induce gene expression changes. These data indicate that quantifying the expression levels of the selected biomarker genes constitutes a useful endpoint to assess the combined toxicity of melamine and cyanuric acid in both male and female rats.     

Utility of urinary organic anion transporter 5 as an early biomarker of obstructive nephropathy

Ureteral obstruction is a relevant cause of kidney damage. The traditional parameters used in clinical practice for the detection of renal injury are insensitive and non-specific for the diagnosis of obstructive renal disease. The organic anion transporter 5 (Oat5) is a carrier expressed exclusively in the kidney. In this study, the Oat5 urinary excretion (Oat5_u) was evaluated as a potential biomarker of obstructive nephropathy, comparing it with traditional markers of renal function and with neutrophil gelatinase-associated lipocalin in urine (NGAL_u), a more recent biomarker of renal pathology. Bilateral ureteral obstruction (BUO) was induced in male Wistar rats, by complete ligation of ureters for 1 hour (BUO1), 2 hours (BUO2), 5 hours (BUO5), or 24 hours (BUO24). After 24 hours of ureteral releasing, urea and creatinine plasma concentrations, creatinine clearance, urinary total proteins, urinary glucose, and alkaline phosphatase activities in urine were evaluated. Oat5 and NGAL levels were assessed in urine samples by immunoblotting. All parameters of renal function were altered in the BUO24 and some also in BUO5, while the Oat5_u increased in all of the experimental groups analyzed. After a long time of ureteral obstruction (BUO24), the urinary excretion of Oat5 markedly increased, in parallel with the alteration in the other parameters evaluated. Nevertheless, in BUO1 and BUO2, Oat5_u appeared as the only parameter modified. Therefore, Oat5_u could be proposed as a novel early biomarker of ureteral obstruction, with the additional potential to inform about the severity of the obstructive injury suffered by the kidney.     

Identification of a sensitive urinary biomarker,selenium-binding protein 1, for early detection of acute kidney injury

Acute kidney injury (AKI) is associated with increased mortality rate in patients but clinically available biomarkers for disease detection are currently not available. Recently, a new biomarker, selenium-binding protein 1 (SBP1), was identified for detection of nephrotoxicity using proteomic analysis. The aim of this study was to assess the sensitivity of urinary SBP1 levels as an early detection of AKI using animal models such as cisplatin or ischemia/reperfusion (I/R). Sprague–Dawley rats were injected with cisplatin (6 mg/kg, once i.p.) and sacrificed at 1, 3, or 5 days after treatment. Ischemia was achieved by bilaterally occluding both kidneys with a microvascular clamp for 45 min and verified visually by a change in tissue color. After post-reperfusion, urine samples were collected at 9, 24, and 48 hr intervals. Urinary excretion of protein-based biomarkers was measured by Western blot analysis. In cisplatin-treated rats, mild histopathologic alterations were noted at day 1 which became severe at day 3. Blood urea nitrogen (BUN) and serum creatinine (SCr) levels were significantly increased at day 3. Levels of urinary excretion of SBP1, neutrophil gelatinase-associated lipocalin (NGAL), and a tissue inhibitor of metalloproteinase-1 (TIMP-1) were markedly elevated at day 3 and 5 following drug treatment. In the vehicle-treated I/R group, serum levels of BUN and SCr and AST activity were significantly increased compared to sham. Urinary excretion of SBP1 and NGAL rose markedly following I/R. The urinary levels of SBP1, NGAL, TIMP-1, and KIM-1 proteins excreted by AKI patients and normal subjects were compared. Among these proteins, a marked rise in SBP1 was observed in urine of patients with AKI compared to normal subjects. Based upon receiver-operator curves (ROC), SBP1 displayed a higher area under the curve (AUC) scores than levels of SCr, BUN, total protein, and glucose. In particular, SBP1 protein was readily detected in small amounts of urine without purification. Data thus indicate that urinary excretion of SBP1 may be useful as a reliable biomarker for early diagnosis of AKI in patients.     

Changes in the concentrations of creatinine, cystatin C and NGAL in patients with acute paraquat self-poisoning

An increase in creatinine >3 μmol/L/h has been suggested to predict death in patients with paraquat self-poisoning and the value of other plasma biomarkers of acute kidney injury has not been assessed. The aim of this study was to validate the predictive value of serial creatinine concentrations and to study the utility of cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) as predictors of outcome in patients with acute paraquat poisoning. The rate of change of creatinine (dCr/dt) and cystatin C (dCyC/dt) concentrations were compared between survivors and deaths. Receiver-operating characteristic (ROC) curves were constructed to determine the best threshold for predicting death. Paraquat was detected in 20 patients and 7 of these died between 18 h and 20 days post-ingestion. The dCr/dt ROC curve had an area of 0.93 and the cut-off was >4.3 μmol/L/h (sensitivity 100%, specificity 85%, likelihood ratio 7). The dCyC/dt ROC curve had an area of 0.97 and the cutoff was >0.009 mg/L/h (sensitivity 100%, specificity 91%, likelihood ratio 11). NGAL did not separate survivors from deaths. Death due to acute paraquat poisoning is associated with changes in creatinine and cystatin concentrations. Further validation of these measurements is needed before they can be adopted in guiding intensive treatments.     

中性粒细胞明胶酶相关脂质运载蛋白对冠状动脉旁路移植术后急性肾损伤的早期诊断价值

目的评价血浆中性粒细胞明胶酶相关脂质运载蛋白（NGAL）对非体外循环冠状动脉旁路移植（CABG）术后急性肾损伤（AKI）的早期诊断价值。方法连续入选自2010年1月至2011年1月因确诊冠状动脉粥样硬化性心脏病入院,拟行择期非体外循环CABG治疗的患者231例。AKI定义为CABG术后48h内最高血清肌酐绝对值升高≥0．3mg／,d1（26．4μmol／L）,或较基线水平升高≥50％。用酶联免疫吸附试验方法检测术前及术后2h血浆NGAL水平,采用受试者工作特征曲线来评价其对AKI的诊断价值,诊断Cut-off值采用约登指数最大值对应的点。结果231例患者中有37例（16．0％）发生AKI。发生AKI患者术前及术后2h血浆NGAL浓度分别为（69±25）和（112±29）μg/L,差异有统计学意义（P〈0．01）;未发生AKI的患者术前和术后2h血浆NGAL浓度分别为（66±24）和（71±21）μg／L,差异有统计学意义（P=0．004）;所有患者术前血浆NGAL浓度差异无统计学意义（P=0．501）,而发生AKI的患者术后2h血浆NGAL浓度明显高于未发生AKI的患者,差异有统计学意义（P〈0．01）。术后2h血浆NGAL水平的药时曲线下面积最大为0．899（95％置信区间：0．843～0．954,P〈0．01）。采用约登指数最大标准选择Cut—off值为85．6μg／L,敏感性和特异性分别为0．865和0．851。结论血浆NGAL可以作为非体外循环CABG术后发生AKI的早期诊断标志物。     

中性粒细胞明胶酶相关脂质运载蛋白与胱抑素C和免疫球蛋白水平对过敏性紫癜儿童肾功能评价的临床意义

目的探讨中性粒细胞明胶酶相关脂质运载蛋白（NGAL）、胱抑素C和免疫球蛋白水平检测在儿童过敏性紫癜（HSP）早期。肾损害诊断中的应用价值及相关性。方法将60例患儿分为HSP普通型组30例、HSP肾型组30例,完全随机选择同期门诊体检正常儿童30例为对照组,检测受试者血浆NGAL、尿胱抑素和免疫球蛋白（IgA、IgM、IgG）的水平,进行比较分析。结果HSP普通型组NGAL、胱抑素C和IgA水平分别为（1．6±0．4）mg／L,（1．4±0．6）mg／L,（1．8±0．5）g/L,HSP肾型组分别为（2．4±1．1）mg／L,（3．6±1．0）mg/L,（2．3±0．5）g/L,对照组分别为（0．3±0．1）mg／L,（0．5±0．1）mg／L,（1．1±0．6）g／L,3组患儿NGAL、胱抑素C和IgA水平比较,差异有统计学意义（P〈0．05）;HSP普通型组IgM、IgG水平分别为（1．2±0．1）g/L,（9．9±2．1）g/L,HSP肾型组（1．3±0．2）g/L,（9．4±3．5）g／L,对照组（1．3±0,4）g／L,（9．4±4．0）g/L,3组IgM、IgG之间比较,差异无统计学意义（P〉0．05）。HSP肾型组较NGAL、胱抑素c和IgA含量高于对照组与HSP普通型组,差异均有统计学意义（均P〈0．05）;NGAL与胱抑素C呈正相关（r=12．36,P〈0．05）;NGAL与IgA呈正相关（r=17．01,P〈0．05）;胱抑素C与IgA呈正相关（r=22．25,P〈0．05）。结论NGAL、胱抑素C和免疫球蛋白水平对于HSP的诊断有一定价值,尤其对患儿肾功能早期损害的诊断,早期联合检测三者的水平,适时给予预防性治疗,对保护HSP患儿的脏器功能、改善预后具有重要临床意义。     

万古霉素用药后血清NGAL水平与肾功能变化的相关性研究

目的： 探讨万古霉素暴露的脓毒症患者血清中性粒细胞明胶酶相关脂质运载蛋白（NGAL）水平与肾功能变化的相关性,评价其在预测万古霉素暴露患者早期肾损害中的作用。方法： 以重症监护病房收治患者中接受万古霉素治疗并进行NGAL检测的脓毒症患者为研究对象。根据患者用药前NGAL水平,将纳入患者分为试验组和对照组2组,其中试验组为NGAL（+）组（≥ 50 ng·L^-1）,对照组为NGAL（-）组。分别记录2组患者用药前NGAL指标以及患者万古霉素用药前后血清肌酐（SCr）变化情况,白细胞计数（WBC）、C-反应蛋白（CRP）及降钙素原（PCT）等数据。以SCr绝对值增加>26.5 μmol·L^-1或增加达到基线值的1.5倍作为急性肾损伤（AKI）的诊断标准,评估NGAL水平与血肌酐变化、WBC、CRP及PCT之间的关系,比较NGAL（+）组和NGAL（-）组用药前后肌酐的变化情况及AKI发生率的统计学差异,并分析肾功能变化的影响因素。结果： 本研究共纳入患者69例,其中试验组28例,对照组41例。万古霉素用药前、后对照组患者血肌酐水平分别为（79.6±22.4）μmol·L^-1和（92.8±60.9）μmol·L^-1,试验组患者用药前后的血肌酐水平分别为（89.9±22.8）μmol·L^-1和（102.3±47.1）μmol·L^-1。2组间及用药前后血肌酐值差异均无统计学意义（P>0.05）。血清NGAL与患者用药前后血肌酐变化水平无相关关系（P=0.168,R=0.176）。试验组与对照组AKI的发生率分别为32.14%和24.39%,试验组略高于对照组,但其差异无统计学意义（P>0.05）。试验组中NGAL水平与WBC、CRP及PCT水平之间均无明显的相关关系。结论： 在患者入住ICU接受万古霉素治疗期间,血清NGAL尚不能证实单独作为万古霉素肾毒性的标记物。     

Comparison of the Mesoscale Discovery and Luminex multiplex platforms for measurement of urinary biomarkers in a cisplatin rat kidney injury model

IntroductionIn the past years several new urinary nephrotoxicity biomarkers have been qualified for use in preclinical studies by the FDA and EMA. Subsequently, kits have been developed to measure these urinary biomarkers on multiplex platforms such as the electro-chemiluminescent based immunoassay from MesoScale Discovery (MSD) and the bead-based immunoassay using Luminex xMAP technology (LMX). The aim of the present study was to compare the two multiplex platforms with respect to the capability of their qualified urinary biomarker panels to measure an increase of these biomarkers relative to histopathological changes in an animal model of nephrotoxicity.MethodsFor comparison of the two platforms we used urine samples from a study with the well-characterized nephrotoxin cisplatin (Cp) in male Wistar rats. The following five biomarkers were measured on both platforms: glutathione S-transferase α (αGST), clusterin (CLU), kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL, a.k.a. lipocalin-2) and osteopontin (OPN). The measurements were compared with respect to both the fold increase observed for each biomarker and the absolute concentrations measured in relation to traditional endpoints for nephrotoxicity in clinical pathology and histopathology.ResultsThe platform comparison revealed the expected increases of urinary biomarkers after Cp treatment with similar results at the fold change level enabling consistent detection of kidney injury. The comparison of the absolute concentrations of biomarkers measured in the two platforms showed differences, the extent of which was analyte-dependent.DiscussionBy comparison of two widely used multiplex platforms, MSD and LMX, for the detection of renal toxicity biomarkers in urine, we observed the expected increases of these biomarkers in response to Cp administration. Depending on the marker, significant differences could be found when comparing the absolute concentrations thus suggesting that baseline levels for each platform will have to be set separately.     

尿中性粒细胞明胶酶相关脂质运载蛋白对儿童急性肾盂肾炎诊断价值的探讨

目的 探讨尿中性粒细胞明胶酶相关脂质运载蛋白（NGAL）对儿童急性肾盂肾炎（APN）的诊断价值。方法 研究对象为 2016 年 12 月—2017 年 5 月收治的尿路感染（UTI）患儿 104 例,包括急性肾盂肾炎 61 例（APN 组）及下尿路感染 43 例（非 APN 组）,均检测血清 β2 微球蛋白（β2-MG）、胱抑素 C（CysC）、C 反应蛋白（CRP）、降钙素原（PCT）和尿 NGAL 的水平,对比 2 组各指标的水平,并进行统计学分析;采用受试者工作特征（ROC）曲线分析各指标对 APN 的诊断价值。结果 APN 组血 CRP、PCT、β2-MG 及尿 NGAL 的水平均高于非 APN 组,差异有统计学意义（P＜0.05）;血 CysC 水平差异无统计学意义。血 CRP、PCT 及尿 NGAL 诊断儿童 APN 的 ROC 曲线下面积（AUC）分别为 0.838、0.898、0.963;血 CRP 最佳临界值为 22.6 mg/L 时,敏感度为 75.4%,特异度为 83.7%;PCT 最佳临界值为 0.285 μg/L 时,敏感度为 77.0%,特异度为 93.0%;当尿 NGAL 最佳临界值为 473 μg/L 时,敏感度为 82.0%,特异度为97.7%。结论 尿 NGAL 对儿童 APN 具有诊断价值,有助于临床对儿童 APN 的早期识别。     

Early urinary biomarkers of renal tubular damage by a high‐salt intake independent of blood pressure in normotensive rats

Dietary sodium intake has been associated with progression to chronic kidney disease (CKD) as well as hypertension. A high‐salt intake causes renal damage independent of hypertension. Because traditional renal biomarkers are insensitive, it is difficult to detect renal injury induced by a high‐salt intake, especially in normotensive patients. Here, we investigated whether newly developed renal biomarkers could be detected earlier than traditional biomarkers under a high‐salt intake, in normotensive rats. Male Wistar Kyoto rats (WKY) received a regular (0.8% NaCl) or salt‐loaded (2, 4, and 8% NaCl) diet from 9 to 17 weeks of age. A urine sample was obtained once a week and urinary vanin‐1, neutrophil gelatinase‐associated lipocalin (NGAL), and kidney injury molecule‐1 (Kim‐1) were measured. At 17 weeks of age, 8% salt‐loaded WKY showed histopathological renal tubular damage and elevated Rac1 activity in renal tissues. Although there was no significant increase in serum creatinine, urinary albumin, N‐acetyl‐β‐D‐glucosaminidase (NAG), or Kim‐1 during the study period among the groups, urinary vanin‐1 and NGAL significantly increased in 8% salt‐loaded WKY from 10 to 17 weeks of age. These results suggest that urinary vanin‐1 and NGAL, which might be induced by salt per se, are potentially earlier biomarkers for renal tubular damage in normotensive rats under a high‐salt intake.     

Change in kidney damage biomarkers after 13 weeks of exposing rats to the complex of Paecilomyces sinclairii and its host Bombyx mori larvae

Complex of Paecilomyces sinclairii and host larvae, Bombyx mori, is a well known health food; however, concerns about nephrotoxicity have been raised. Kidney toxicity was investigated after 13 weeks of administering the complex orally to rats with parameters including blood urea nitrogen (BUN), creatinine, and kidney damage biomarkers, beta-2-microglobulin (β2m), glutathione S-transferase alpha (GST-α), kidney injury molecule 1 (KIM-1), tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), vascular endothelial growth factor (VEGF), calbindin, clusterin, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), and osteopontin. Dose-dependent kidney cell karyomegaly and tubular hypertrophy were observed, with higher severity in males. There was a dose-dependent increase in KIM-1 and TIMP-1 levels in kidney and urinary KIM-1, cystatin C, β2m, and osteopontin levels. KIM-1 and TIMP-1 increased in male kidneys had not recovered by 2 weeks after stopping exposure. Cystatin C in kidney was significantly lowered in all treatment groups at 13 weeks of administration. All the changes were more noticeable in males. These data indicate that the complex damage renal tubule cells with histopathological lesions and changes in biomarker levels. Kidney and urinary KIM-1 and cystatin C were the most markedly affected and early increased indicators among biomarkers tested, whereas BUN and creatinine were not affected.