肾小球疾病患者尿沉渣足细胞分子podocin和podocalyxin分析

目的：以ELISA法检测尿沉渣足细胞podocin,podocalyxin排泌并观察其与不同肾小球疾病的关系。方法：共收集我院自2010年5月～8月以来行肾活检证实为肾小球疾病的患者,收集其临床资料,并以ELISA法检测尿沉渣足细胞分子podocin,podocalyxin。结果：共40个患者,男15例,女25例,平均年龄（38.27±16.33）岁,增殖性肾小球疾病患者19例：IgA肾病10例,新月体性肾炎2例,IgM肾病2例,Ⅳ（A/G）型狼疮性肾炎5例;非增殖性肾小球疾病患者19例：微小病变型（MCD）5例,局灶节段硬化性肾小球肾炎（FSGS）8例,膜性肾病（MN）6例,另原发性肾淀粉样变性2例,对照健康自愿者10例。尿podocin分子排泌在正常对照组最低,在增殖性肾小球疾病和非增殖性肾小球疾病间差异无统计学意义（P〉0.05）,增殖性肾小球疾病尿podocin排泌高于肾淀粉样变性患者（P〈0.05）。新月体肾炎的尿podocin排泌显著高于其他肾小球疾病（P〈0.05）,后依次FSGS,IgA肾病,狼疮性肾炎,MN,IgM肾病,MCD;尿沉渣podocalyxin排泌在正常对照组最低,而增殖性肾小球肾炎和非增殖性肾小球肾炎间差异无统计学意义（P〉0.05）。新月体肾炎尿podocalyxin排泄量最高,其后依次为FSGS,IgA肾病,MN,狼疮性肾炎,MCD,IgM肾病,以肾淀粉样变性最低。尿podocalyxin与podocin呈正相关,尿podocin与血C3呈负相关。结论：ELISA法检测尿沉渣足细胞分子检测可对肾小球疾病患者的肾病理类型提供参考,以正常人尿podocin,podocalyxin排泌最少,增殖性肾小球疾病和非增殖性肾小球疾病间差异无统计学意义,新月体性肾炎尿沉渣podocin及Podocalyxin高于其他疾病患者,FSGS患者的尿沉渣podocin及Podocalyxin排泌量也较多,肾淀粉样变性患者的尿沉渣podocin及Podocalyxin最低,血清C3与尿podocin的排泌呈负相关。     

Nephrin和WT1在原发性肾病综合征患者肾小球的表达及意义

目的探讨原发肾病综合征（NS）患者肾小球足细胞中裂孔隔膜蛋白nephrin、Wilm肿瘤蛋白1（WTl）的表达及分布特征。方法选择肾病综合患者80例（NS组）,根据其病理诊断水平分为微小病变（MCN）组、IgA肾病组、膜性肾病（MN）组、局灶节段性肾小球硬化（FSGS）组,每组20例;另设正常对照组10名。采用免疫组织化学方法检测各组肾小球nephrin、WT1的表达指数（EI）,并进行组间比较。结果①正常对照组nephrin在肾小球毛细血管壁,呈均匀、线状分布;肾病综合征组患者nephrin在肾小球中分布不均,部分区域染色明显减弱,部分区域线性消失,呈颗粒状或者团块状。MN组和IgA肾病组与正常对照组比较显著降低（P〈0．05）。nephrin的表达水平与24h尿蛋白定量呈负相关（r=-0．216,P〈0．05）,与白蛋白呈正相关（r=0．300,P〈O．01）。②WT1在肾小球足细胞胞核内表达。MCN组、IgA肾病组及FSGS组与正常对照组比较表达下降（P〈0．05）。WT1的表达与24h尿蛋白定量呈负相关（r=-0．304,P〈0．05）,与血浆白蛋白呈正相关（r=0．338,P〈0．01）。结论NS早期即可出现肾小球足细胞中nephrin、WT1的表达和分布减少,而且随着病变的加重,这种变化愈发明显。足细胞病不仅导致大量蛋白尿发生,而且还可能与肾小球硬化的发生有关。     

肾小球肾炎足细胞脱落与肾组织钠氢交换调节因子2表达的研究

目的探讨肾小球足细胞脱落情况及其与病理改变的关系;探讨6类肾炎中肾组织钠氢交换调节因子2（NHERF2）基因表达量的变化及其与足细胞损伤的关系。方法将患者分为肾炎组（原发性肾炎和狼疮性肾炎）、非肾炎组、健康对照组;用间接免疫荧光法检测尿足细胞数量,用荧光定量PCR检测肾组织NHERF2蛋白,比较不同类型肾炎足细胞脱落情况及NHERF2基因表达量。结果原发性肾炎和狼疮性肾炎（LN）组患者尿足细胞脱落较健康对照组显著增多（P〈0．05）;活动期LN患者尿足细胞脱落较缓解期LN显著增多（P〈0．05）;原发性肾炎组中局灶节段硬化性肾小球肾炎（FSGS）患者尿足细胞脱落最多,其次为膜性肾病（MS）患者,二者与健康对照组相比,差异均有统计学意义（P〈0．05）。MS患者尿足细胞脱落比微小病变性肾病（MCD）患者显著增多（P〈0．05）。原发性肾炎组和LN组患者肾组织NHERF2基因表达量均较非肾炎组显著降低（P〈0．05）。肾炎患者尿足细胞脱落数量和肾组织NHERF2基因表达之间具有相关性（r=0．318,P〈0．05）。结论根据尿足细胞脱落数量可初步推断FSGS和LN的病理改变类型、预测LN的疾病进展和预后,可能为临床MS与MCD的鉴别提供依据;证明肾小球足细胞脱落可能与肾组织NHERF2基因表达减低有关,提示足细胞NHERF2基因表达缺陷可能参与足细胞损伤脱落的机制。     

高糖对小鼠肾小球足细胞podocalyxin mRNA表达的影响

目的探讨高糖对小鼠肾小球足细胞podocalyxin mRNA表达的影响。方法以体外培养的小鼠足细胞为研究对象,将细胞分组,即正常对照组（NG组）：D-葡萄糖5．56mmol／L;高糖培养组（HG组）;D-葡萄糖25．0mmol／L。应用逆转录-PCR技术,检测高糖培养不同时间点对足细胞表达podocalyxin mRNA的影响;Western blot印迹分析检测细胞转录因子WT-1蛋白变化。结果①逆转录-PCR技术显示随着高糖培养时间增加,HG组肾小球足细胞与WG组比较、以及HG组（第6、12、24h）组间比较,podocalyxin mRNA表达均减少（P〈0．05）。②培养的足细胞表达基础水平的WT-1蛋白,但在经高糖培养2h后其表达即开始下降（P〈0．05）。结论高糖培养使小鼠肾小球足细胞podocalyxin mRNA和转录因子WT-1蛋白表达下降。     

足细胞异常与糖尿病肾病

糖尿病肾病是糖尿病常见的并发症之一。肾小球足细胞损伤是糖尿病肾病发生发展中的一个重要环节,与蛋白尿产生和肾小球硬化进展明显相关。糖尿病肾病时足细胞的异常改变包括：细胞肥大、细胞数量减少、足突消失、裂孔隔膜相关蛋白（nephrin、podocin、ZO-1、P—cadherin、α-actinin-4、synaptopodin等）和顶膜区蛋白podocalyxin表达异常、足细胞分泌异常及与此相关的肾小球基底膜改变。本篇综述详细探讨糖尿病时足细胞的上述结构和功能异常以及它们在糖尿病肾病发生和发展中的作用。     

复方积雪草防治局灶节段性肾小球硬化模型大鼠足细胞损伤的实验研究

目的:探讨复方积雪草对局灶节段性肾小球硬化(focal segmental glomerulo sclerosis,FSGS)模型大鼠足细胞裂孔膜蛋白nephrin、podocin表达的影响,阐述其延缓肾小球硬化的部分分子生物学机制。方法:采用左肾摘除+阿霉素重复静脉注射方法建立FSGS模型。复方组分别予高中低剂量复方积雪草膏剂灌胃;对照组予苯那普利混悬液;于第8周末留取24h尿蛋白定量,检测血肌酐(Scr)、尿素氮(BUN)、胆固醇(TC)、三酰甘油(TG)和血浆蛋白(Alb);留取右肾标本,光镜标本行HE染色;用免疫组化法观察裂孔膜蛋白nephrin和podocin表达;RT-PCR法检测肾组织nephrin和podocinmRNA表达。结果:各复方组24h尿蛋白定量及血Scr、BUN、TC、TG较模型组有显著改善,且与西药组疗效相似。RT-PCR及免疫组化结果显示模型组足细胞裂孔膜蛋白表达较正常组明显降低(P<0.05)。而各治疗组表达较模型组均有明显增加(P<0.05),且与正常组比较差异无统计学意义(P>0.05)。结论:复方积雪草能通过上调模型大鼠肾小球内nephrin和podocin分子表达,减轻足细胞损伤,延缓肾小球硬化。     

IgA肾病患者尿足细胞排泄与临床病理相关性分析

目的观察原发性IgA肾病患者尿足细胞排泄、肾小球足细胞病变,分析其与临床病理之间的关系。方法50例经肾活检明确诊断的IgA肾病患者和10名健康志愿者,利用podocalyxin（PCX）作为标记蛋白,标记尿液和肾组织足细胞,收集患者肾活检时临床资料,各项病理指标和肾组织足细胞PCX荧光表达采用不同的半定量积分法进行评分,电镜检测肾小球外周袢的足突宽度。结果①IgA肾病患者中尿足细胞染色阳性为32例（64％）,较健康对照者有统计学差异。②IgA肾病伴尿足细胞阳性患者尿蛋白水平、血肌酐（SCr）、平均动脉压（MAP）较尿足细胞阴性患者增高,血浆白蛋白（Alb）、肾小球滤过率（GFR）降低（P〈0．05）。③光镜示IgA肾病伴尿足细胞阳性患者肾小球硬化程度、新月体发生率较尿足细胞阴性患者明显增高（P〈0．05）,但小管间质病变与肾组织足细胞PCX表达阳性指数,2组比较无统计学差异。④电镜结果提示IgA肾病患者尿足细胞阳性足突宽度明显增宽（P〈0．05）。结论足细胞尿是反映肾脏疾病轻重的一个指标,足细胞尿与肾脏病理类型有一定关系,IgA肾病患者尿足细胞排泄指标是否能够独立预测患者的预后还有待证实。     

局灶节段性肾小球硬化症大鼠尿足细胞动态检测及其意义

目的建立局灶节段性肾小球硬化症(FSGS)大鼠模型,观察尿中脱落的肾小球足细胞的变化,并探讨其意义。方法FSGS组(n=7):采用左颈静脉插管一次性缓慢注射嘌呤霉素核苷酸(PAN,9mg/100g体重的方法建立)FSGS大鼠模型。正常对照组(n=5):注射等量生理盐水,实验周期20周。动态检测24h尿蛋白定量;间接免疫荧光方法动态检测尿沉渣足细胞特异性标志蛋白podocalyxin(PCX)、Wilm'stumor鄄1(WT鄄1);20周末肾组织光镜下观察肾小球病变;电镜观察肾小球足细胞的改变;免疫荧光染色观察肾小球内PCX和成熟足细胞特异性标志蛋白synaptopodin(PP44)的表达。结果FSGS组大鼠24h尿蛋白定量在第天较注射前明显升高,第312天达到高峰[(672.74±98.72)比(19.31±3.15)mg/24h,P<0.01),此后开始下降,于第6周接近注射前水平,持续至11周[(35.46±14.88)比(19.31±3.15)mg/24h,P=0.0238];从12周开始再度缓慢升高,持续高水平至20周,为注射前近7倍[(140.61±68.90)比(19.31±3.15)mg/24h,P<0.01]。FSGS组大鼠从12周开始,尿足细胞出现阳性(>1～5个/HP),持续至20周。光镜显示,30%～50%肾小球出现不同程度的局灶节段性硬化;电镜证实足突部分融合并可见足突与基底膜剥离。足细胞特异标记蛋白PCX、PP44在肾小球节段性硬化部位呈现节段性缺失。对照     

益肾活血方抑制足细胞转分化减缓FSGS模型大鼠疾病进展的实验研究

目的:通过观察益肾活血方对局灶节段性肾小球硬化模型大鼠尿蛋白,肾组织结构,足细胞特异性蛋白WT1、nephrin,转分化相关指标α-SMA的影响。探讨益肾活血方对局灶节段性肾小球硬化的调控机制。方法:7～8周龄雄性Sprague Dawley大鼠,尾静脉注射多柔比星(4 mg·kg~(-1)·次~(-1)) 2次,制备FSGS模型。成模后,按24 h尿蛋白定量随机分为模型组、贝那普利组(5 mg/kg)、益肾活血方高剂量组(2 g/kg)、益肾活血方低剂量组(1 g/kg),每组9只;选择另外10只同周龄大鼠为正常组。连续给药8周。在实验结束时,检测体重、24 h尿蛋白定量(24 h U-Pr)、血肌酐、尿素氮;行肾脏组织HE、PAS染色; Western blot法检测WT1、nephrin、α-SMA蛋白表达。结果:与模型组相比,高剂量组24 h U-Pr显著降低(P 0. 05),体重显著升高(P 0. 05),肾小球硬化程度显著改善(P 0. 05); WT1蛋白在高低剂量组肾组织中的表达显著升高(P 0. 05); nephrin在治疗后有增加趋势;α-SMA模型组中表达增加(P 0. 01),益肾活血方治疗后表达下调(P 0. 05)。结论:益肾活血方能够减少尿蛋白排泄,减轻肾组织病理损害,降低肾小球硬化程度;其作用机制可能与抑制足细胞转分化,保护足细胞结构和数量(nephrin、WT1),减少足细胞损伤有关。     

缬沙坦联合苯那普利对糖尿病大鼠足细胞损伤的影响及肾脏保护机制的研究

目的：研究缬沙坦联合苯那普利对糖尿病大鼠足细胞损伤的影响及肾脏保护机制的作用。方法：将SD大鼠随机分为正常对照组（A组），糖尿病对照组（B组），糖尿病苯那普利治疗组（C组），糖尿病缬沙坦治疗组（D组），缬沙坦联合苯那普利（E组）。分别于实验第4、6周末各组随机取8只测定大鼠平均动脉压、血糖、血肌酐、尿肌酐、肾重／体重、尿白蛋白排泄率，对肾脏标本进行光镜、电镜观察，用图像分析仪测量各组大鼠的平均肾小球横截面积、平均肾小球体积，并于6周末用逆转录-PCR（RT-PCR）方法检测各组肾皮质TGF-β1 mRNA表达。采用免疫组织化学染色检查足细胞特异标记物nephrin、desmin，对足细胞进行准确的定位及其密度定量观察，同时结合临床和肾组织病理有关指标进行分析。结果：苯那普利、缬沙坦、缬沙坦联合苯那普利治疗均使Ccr、肾重／体重、尿白蛋白排泄率、TGF-β1mRNA表达降低，而缬沙坦联合苯那普利组对TGF-β1mRNA抑制程度最大，同时肾脏病理变化亦最轻。B组、E组均伴肾小球足细胞数目及密度的减少，其中以B组最为显著，C组、D组次之，E最轻。足细胞数目及其密度与尿蛋白量呈显著负相关（P〈0．01）。nephrin、desmin在A组沿肾小球基底膜呈连续、线形分布。C组、D组、E组nephrin、desmin的表达量降低，与正常组织比较，无统计学意义，B组nephrin、desmin的表达呈点状、短线条状，与正常组织比较，有统计学意义（P〈0．05）。糖尿病大鼠足细胞数目的减少还与肾小球病理改变相关，足细胞融合、微绒毛化改变较多，肾小球硬化数明显增多。结论：糖尿病大鼠表现出肾小球足细胞数目及其密度的减少，肾小球足细胞中nephrin、desmin的表达和分布的减少，足细胞病变不仅导致大量白蛋白尿的发生，而且还与肾小球硬化和肾功?     

Urinary podocytes in primary focal segmental glomerulosclerosis

BACKGROUND/AIM: Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome. Although the pathogenesis is not known, recent studies suggest that FSGS may be a podocyte disease. The aim of this study was to look for podocyte injury in this disease, using measurements of urinary podocytes. METHODS: We examined the first morning urine of the day collected from 71 patients (45 men and 26 women, median age and range 11.2 and 3-29 years) diagnosed as having nephrotic syndrome. Freshly voided urine samples were examined by immunofluorescence labeling using monoclonal antibodies against human podocalyxin. Renal histological examinations were performed in 58 of the 71 patients: 28 had minimal-change disease, 20 had FSGS, and 10 had membranous nephropathy. RESULTS: Median and range of urinary podocytes measured were 0.2 and 0-40.8 cells/ml for 71 patients with nephrotic syndrome and 0 and 0-0.8 cells/ml for normal healthy control subjects (n = 200). Patients with FSGS had significantly higher levels of urinary podocytes (median and range 1.3 and 0-40.8 cells/ml) than those with minimal-change disease (median and range 0 and 0-6.9 cells/m; p = 0.003) or membranous nephropathy (median and range 0 and 0-1.4 cells/ml; p = 0.02). CONCLUSIONS: The urinary excretion of podocytes is significantly higher in patients with FSGS as compared with those having membranous nephropathy or minimal-change disease. These findings suggest that podocyte injury and loss in the urine may have an important role in the pathogenesis of FSGS.     

Ultrastructural Features and Expression of Cytoskeleton Proteins of Podocyte from Patients with Minimal Change Disease and Focal Segmental Glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) have been suggested for the category of podocytopathies. An ultrastructural observation and immunogold labeling for cytoskeleton proteins of podocytes on 11 cases each of FSGS and MCD were performed. Compared to MCD, more severe ultrastructural alterations of podocyte were identified in FSGS, which were characterized by higher frequency of mat-like condensation of microfilaments in the foot process and the detachment of the foot process from glomerular basement membrane. The labeling of α-actinin of podocytes in FSGS was significantly higher than MCD, which suggested an abnormal expression of cytoskeleton protein of podocyte in FSGS. The present study demonstrated a much more severe podocyte injury at the ultrastructural level in FSGS than in MCD.     

一种成人肾病综合征患者尿沉渣足细胞分子nephrin及Podocalyxin检测方法

目的:探讨采用ELISA方法以尿AQP(Aquaporin)-2校正检测肾病综合征尿nephrin podocalyxin排泌,以帮助评估成人肾病综合征的诊断和病情。方法:入组71例经肾穿刺明确病理诊断的成人肾病综合征(NS)患者,包括20例增殖性肾小球疾病的患者,49例非增殖的患者和2例淀粉样变性患者。22例FSGS患者(其中13例确定FSGS亚型诊断)。选取10例健康志愿者作为研究对照组。用ELISA法测定尿nephrin,podocalyxin和AQP-2。以尿AQP2作为内参照校正尿nephrin(neph/AQP)和podocalyxin(PCX/AQP)。结果:尿neph/AQP和PCX/AQP正相关(R=0.616,P<0.001),正常人尿neph/AQP和PCX/AQP显著低于NS患者(P<0.05),增殖和非增殖性肾病综合征患者的尿neph/AQP和PCX/AQP差异无统计学意义(P>0.05),FSGS患者尿neph/AQP和PCX/AQP中显著高于其他NS患者(P<0.05),在IgMN患者尿neph/AQP和PCX/AQP增加,肾淀粉样变性患者的尿neph/AQP和PCX/AQP较少。对13例明确FSGS病理亚型诊断的患者尿neph/AQP和PCX/AQP进行评估,发现各组间差异无统计学意义(P>0.05),但以细胞型FSGS尿neph/AQP排泌最高,NOS型其次,顶端型再次,以脐部型最低。尿PCX/AQP则以细胞型FSGS排泌最高,NOS型其次,脐部型再次,顶端型最低。对于肾病综合征患者FSGS的诊断,ROC曲线分析表明,当尿neph/AQP取临界值为0.165时其灵敏度为0.864,而特异性为0.603,尿PCX/AQP取临界值3.056时其灵敏度为0.773,特异性为0.672。结论:采用ELISA方法的以AQP-2作为内参检测成人肾病综合征尿足nephrin,podocalyxin较为简便。IgMN患者尿neph/AQP和PCX/AQP增高,肾淀粉样变性患者的尿neph/AQP和PCX/AQP较低。FSGS患者尿neph/AQP和PCX/AQP高于其他肾病综合征患者,在FSGS亚型中以细胞型及NOS型稍高于其他亚型FSGS患者,该方法还有助于在临床肾病综合征患者中帮助诊断FSGS。     

Thiazolidinedione attenuate proteinuria and glomerulosclerosis in Adriamycin-induced nephropathy rats via slit diaphragm protection

Aim:   The slit diaphragm (SD) of podocyte impairment contributes to massive proteinuria and progressive glomerulosclerosis in many human glomerular diseases. The aim of the study was to determine if thiazolidinedione (TZD) reduce proteinuria and glomerulosclerosis in focal segmental glomerulosclerosis (FSGS) by preserving the structure and function of SD.
Methods:   Adriamycin-induced FSGS rat models were employed. Urinary protein content was measured dynamically during the experiment. Additional biochemical parameters in serum samples were measured after the animals were killed. Glomerular sclerosis index (SI) and podocyte foot processes fusion rate (PFR) were evaluated. The protein and mRNA expressing levels of nephrin, podocin and CD2-associated protein (CD2AP) in glomeruli were assessed by immunohistochemistry and real-time quantitative polymerase chain reaction, respectively. The density of podocytes was also evaluated after anti-Wilms' tumour-1 immunohistochemical staining.
Results:   Rosiglitazone treatment partially reduced proteinuria, but did not significantly affect the serum levels of triglyceride, cholesterol, albumin, glucose, urea nitrogen and creatinine in Adriamycin-induced FSGS rats. Glomerular SI and podocyte foot PFR were significantly attenuated by rosiglitazone treatment. Rosiglitazone prevented the reduction of nephrin, podocin and CD2AP protein expression induced by Adriamycin, however, the mRNA expression levels of these SD-related markers did not change significantly. Rosiglitazone therapy did not reverse Adriamycin-mediated reduction of the density of podocytes.
Conclusions:   The study data suggest that TZD are promising therapeutic agents on FSGS, and the mechanism may be mediated in part by directly protecting the structure and function of SD.     

Podocyte proteins in Galloway-Mowat syndrome

Galloway-Mowat syndrome is an autosomal recessive disorder characterized by early onset nephrotic syndrome and central nervous system anomalies. Mutations in podocyte proteins, such as nephrin, α-actinin 4, and podocin, are associated with proteinuria and nephrotic syndrome. The genetic defect in Galloway-Mowat syndrome is as yet unknown. We postulated that in Galloway-Mowat syndrome the mutation would be in a protein that is expressed both in podocytes and neurons, such as synaptopodin, GLEPP1, or nephrin. We therefore analyzed kidney tissue from normal children (n=3), children with congenital nephrotic syndrome of the Finnish type (CNF, n=3), minimal change disease (MCD, n=3), focal segmental glomerulosclerosis (FSGS, n=3), and Galloway-Mowat syndrome (n=4) by immunohistochemistry for expression of synaptopodin, GLEPP1, intracellular domain of nephrin (nephrin-I), and extracellular domain of nephrin (nephrin-E). Synaptopodin, GLEPP1, and nephrin were strongly expressed in normal kidney tissue. Nephrin was absent, and synaptopodin and GLEPP1 expression were decreased in CNF. The expression of all three proteins was reduced in MCD and FSGS; the decrease in expression being more marked in FSGS. Synaptopodin, GLEPP1, and nephrin expression was present, although reduced in Galloway-Mowat syndrome. We conclude that the reduced expression of synaptopodin, GLEPP1, and nephrin in Galloway- Mowat syndrome is a secondary phenomenon related to the proteinuria, and hence synaptopodin, GLEPP1, and nephrin are probably not the proteins mutated in Galloway-Mowat syndrome. Received: 27 April 2001 / Revised: 15 June 2001 / Accepted: 18 June 2001     

Sphingomyelinase-Like Phosphodiesterase 3b Expression Levels Determine Podocyte Injury Phenotypes in Glomerular Disease

Diabetic kidney disease (DKD) is the most common cause of ESRD in the United States. Podocyte injury is an important feature of DKD that is likely to be caused by circulating factors other than glucose. Soluble urokinase plasminogen activator receptor (suPAR) is a circulating factor found to be elevated in the serum of patients with FSGS and causes podocyte αVβ₃ integrin-dependent migration in vitro. Furthermore, αVβ₃ integrin activation occurs in association with decreased podocyte-specific expression of acid sphingomyelinase-like phosphodiesterase 3b (SMPDL3b) in kidney biopsy specimens from patients with FSGS. However, whether suPAR-dependent αVβ₃ integrin activation occurs in diseases other than FSGS and whether there is a direct link between circulating suPAR levels and SMPDL3b expression in podocytes remain to be established. Our data indicate that serum suPAR levels are also elevated in patients with DKD. However, unlike in FSGS, SMPDL3b expression was increased in glomeruli from patients with DKD and DKD sera-treated human podocytes, where it prevented αVβ₃ integrin activation by its interaction with suPAR and led to increased RhoA activity, rendering podocytes more susceptible to apoptosis. In vivo, inhibition of acid sphingomyelinase reduced proteinuria in experimental DKD but not FSGS, indicating that SMPDL3b expression levels determined the podocyte injury phenotype. These observations suggest that SMPDL3b may be an important modulator of podocyte function by shifting suPAR-mediated podocyte injury from a migratory phenotype to an apoptotic phenotype and that it represents a novel therapeutic glomerular disease target.     

Urine Podocyte mRNAs,Proteinuria, and Progression in Human Glomerular Diseases

Model systems demonstrate that progression to ESRD is driven by progressive podocyte depletion (the podocyte depletion hypothesis) and can be noninvasively monitored through measurement of urine pellet podocyte mRNAs. To test these concepts in humans, we analyzed urine pellet mRNAs from 358 adult and pediatric kidney clinic patients and 291 controls (n=1143 samples). Compared with controls, urine podocyte mRNAs increased 79-fold (P<0.001) in patients with biopsy-proven glomerular disease and a 50% decrease in kidney function or progression to ESRD. An independent cohort of patients with Alport syndrome had a 23-fold increase in urinary podocyte mRNAs (P<0.001 compared with controls). Urinary podocyte mRNAs increased during active disease but returned to baseline on disease remission. Furthermore, urine podocyte mRNAs increased in all categories of glomerular disease evaluated, but levels ranged from high to normal, consistent with individual patient variability in the risk for progression. In contrast, urine podocyte mRNAs did not increase in polycystic kidney disease. The association between proteinuria and podocyturia varied markedly by glomerular disease type: a high correlation in minimal-change disease and a low correlation in membranous nephropathy. These data support the podocyte depletion hypothesis as the mechanism driving progression in all human glomerular diseases, suggest that urine pellet podocyte mRNAs could be useful for monitoring risk for progression and response to treatment, and provide novel insights into glomerular disease pathophysiology.Human glomerular diseases are heterogeneous but can collectively be viewed as a spectrum of podocytopathies.¹ Podocyte depletion per se causes glomerulosclerosis in model systems^2–5 and is associated with progressive glomerulosclerosis in humans.^6–12 Podocyte damage causes damage to other podocytes¹³ and activation of the renin-angiotensin system (RAS), which, in turn, drives angiotensin II–dependent further podocyte detachment from destabilized glomeruli.¹⁴ In model systems glomerulosclerosis is initiated when >30% of podocytes have been lost from glomeruli.¹⁴ Quantitative podocyte depletion from glomeruli results in mesangial expansion (10%–20% depletion), adhesions to the Bowman capsule (30% depletion), FSGS (30%–50% depletion), and then global sclerosis (70%–90% depletion) associated with interstitial fibrosis.^4,14 Model systems demonstrate that throughout the progression process podocytes continue to detach and appear in the urine, where they can be monitored noninvasively through quantitation of urine pellet mRNAs.^14–17 Collectively, these findings describe key elements of the podocyte depletion hypothesis for progression of glomerular diseases, whereby progressive depletion of podocytes leads through a series of stages to glomerulosclerosis and ultimately to ESRD.Although increased urine podocyte excretion has also been documented in some inflammatory and noninflammatory glomerular diseases in humans,^12,18–35 the role of podocyte depletion in progression remains unproven. We therefore used urine pellet mRNAs to test the hypothesis that progression to ESRD in human glomerular diseases would also be associated with increased urine podocyte mRNAs, regardless of the underlying cause of glomerular injury. Because proteinuria is a well established marker of kidney disease progression^36,37 but varies in extent and relationship to progression in different diseases, we also examined the relationship between proteinuria and rate of podocyte detachment. Establishing that human glomerular diseases follow the rules defined in model systems of progression would provide a foundation for understanding the progression mechanism in human glomerular diseases and the potential for urine podocyte mRNAs to be clinically useful.     

A Form of Apolipoprotein A‐I Is Found Specifically in Relapses of Focal Segmental Glomerulosclerosis Following Transplantation

Recurrence of idiopathic focal segmental glomerulosclerosis (FSGS) following kidney transplantation occurs in a large percentage of patients. Accurate prediction of recurrence and elucidation of its pathogenesis are major therapeutic goals. To detect differential proteins related to FSGS recurrence, proteomic analysis was performed on plasma and urine samples from 35 transplanted idiopathic FSGS patients, divided into relapsing and nonrelapsing. Several proteins were detected increased in urine of relapsing FSGS patients, including a high molecular weight form of apolipoprotein A‐I, named ApoA‐Ib, found exclusively in relapsing patients. This finding was verified by Western blot individually in the 35 patients and validated in an independent group of 40 patients with relapsing or nonrelapsing FSGS, plus two additional groups: FSGS‐unrelated patients showing different proteinuria levels (n = 30), and familial FSGS transplanted patients (n = 14). In the total of 119 patients studied, the ApoA‐Ib form was detected in 13 of the 14 relapsing FSGS patients, and in one of the 61 nonrelapsing patients. Only one of the 30 patients with FSGS‐unrelated proteinuria tested positive for ApoA‐Ib, and was not detected in familial patients. Urinary ApoA‐Ib is associated with relapses in idiopathic FSGS and warrants additional investigation to determine its usefulness as biomarker of relapse following transplantation.     

尿液足细胞检测及其临床意义的探讨

目的：介绍一种尿液足细胞的检测方法并探讨其临床意义.方法：留取患者100 ml晨尿,将其置细胞涂片离心机制成尿液涂片,将涂片采用小鼠单克隆抗人足细胞标记蛋白-podocalyxin （PCX）抗体进行间接免疫荧光染色.结果：（1）小鼠单克隆抗人足细胞（PCX）抗体与足细胞特异性结合,与红细胞、白细胞和上皮细胞无特异性结合,可用于检测尿足细胞;（2）在多种病理类型的肾小球疾病中尿足细胞呈阳性,正常成人对照组足细胞均为阴性.（3）经统计尿足细胞阳性率前3组的分别为：紫癜性肾炎,局灶节段肾小球硬化,IgA肾病.结论：运用小鼠单克隆抗人足细胞（PCX）抗体检测尿足细胞是一种特异性的方法,在肾病患者中有检测意义.