Synaptopodin Is Dispensable for Normal Podocyte Homeostasis but Is Protective in the Context of Acute Podocyte Injury

Open in a separate window     

Podocyte COX-2 exacerbates diabetic nephropathy by increasing podocyte (pro)renin receptor expression

Diabetic nephropathy (DN) increases podocyte cyclooxygenase-2 (COX-2) expression, and COX-2 inhibition reduces proteinuria and glomerular injury in animal models of diabetes. To investigate the role of podocyte COX-2 in development of diabetic nephropathy, we employed a streptozotocin model of diabetic mellitus in wild-type and transgenic mice expressing COX-2 selectively in podocytes. Progressive albuminuria developed only in diabetic COX-2 transgenic mice despite hyperglycemia, BP, and GFR being similar to those in wild-type mice. Transgenic mice also manifested significant foot-process effacement, moderate mesangial expansion, and segmental thickening of the glomerular basement membrane. In cultured podocytes overexpressing COX-2, high glucose induced cell injury and increased both expression of the pro(renin) receptor and activation of the renin-angiotensin system. Downregulation of the (pro)renin receptor attenuated the injury induced by high glucose. In vivo, podocyte pro(renin) receptor expression increased in diabetic COX-2-transgenic mice, and treatment with a COX-2 inhibitor abrogated the upregulation of (pro)renin receptor and reduced albuminuria, foot-process effacement, and mesangial matrix expansion. In summary, these results demonstrate that increased expression of podocyte COX-2 predisposes to diabetic glomerular injury and that the (pro)renin receptor may be one mediator for this increased susceptibility to injury.     

Unraveling the Role of Podocyte Turnover in Glomerular Aging and Injury

Podocyte loss is a major determinant of progressive CKD. Although recent studies showed that a subset of parietal epithelial cells can serve as podocyte progenitors, the role of podocyte turnover and regeneration in repair, aging, and nephron loss remains unclear. Here, we combined genetic fate mapping with highly efficient podocyte isolation protocols to precisely quantify podocyte turnover and regeneration. We demonstrate that parietal epithelial cells can give rise to fully differentiated visceral epithelial cells indistinguishable from resident podocytes and that limited podocyte renewal occurs in a diphtheria toxin model of acute podocyte ablation. In contrast, the compensatory programs initiated in response to nephron loss evoke glomerular hypertrophy, but not de novo podocyte generation. In addition, no turnover of podocytes could be detected in aging mice under physiologic conditions. In the absence of podocyte replacement, characteristic features of aging mouse kidneys included progressive accumulation of oxidized proteins, deposits of protein aggregates, loss of podocytes, and glomerulosclerosis. In summary, quantitative investigation of podocyte regeneration in vivo provides novel insights into the mechanism and capacity of podocyte turnover and regeneration in mice. Our data reveal that podocyte generation is mainly confined to glomerular development and may occur after acute glomerular injury, but it fails to regenerate podocytes in aging kidneys or in response to nephron loss.Chronic loss of kidney function is of significant public health importance not only because of high prevalence but also because it is a major independent risk factor for cardiovascular morbidity and mortality.¹ Aged kidneys display an increased susceptibility for progressive diseases, suggesting that overlapping molecular programs contribute to organ aging and disease progression.² Recent data indicate that a decrease in the number of glomerular podocytes is an important predictor for kidney aging, and podocytes are considered the weak link in the progression of CKD.³ Animal models have shown that podocyte depletion of up to 20% can be tolerated before a scarring response takes place,⁴ but residual podocytes are unable to undergo cell division.^5–7 Although it is widely believed that glomeruli have only a limited capacity to resolve lesions, cases of potential podocyte regeneration and disease reversal have been described.^8–10 These recent observations have instigated hope of finding ways to stimulate kidney regeneration. So far, two potential podocyte progenitor niches, bone marrow cells and parietal epithelial cells, have been characterized.^11–14 Bone marrow transplantation has an ameliorating effect in several animal models of glomerular disease,^15–18 but the underlying mechanisms remain poorly understood. In humans, Y-chromosome–positive podocytes have been detected in kidneys transplanted from females to males.¹² Located directly adjacent to podocytes, parietal epithelial cells express the stem cell markers CD24 and CD133 in human tissue and are capable of self-renewal, as well as differentiation into several cell types, including podocytes.^11,14,19In this study, a novel flow cytometry–based quantitative method was devised to assess the regenerative capacity of podocytes during diphtheria toxin (DT)–mediated acute podocyte loss, models of chronic nephron loss, and kidney aging.     

ERK1/2对高糖环境下足细胞凋亡的作用及来氟米特对其的影响

目的：观察ERK1/2对高糖环境下足细胞凋亡的作用及来氟米特对其的影响。方法：培养的人足细胞分为正常糖组、高渗对照组、高糖组,高糖组按不同刺激时间又分为0.5h、1h、6h、12h、24h5组,应用Western印迹分析法检测各组足细胞ERK1/2信号途径中ERK1/2蛋白活化的变化。足细胞凋亡检测：将足细胞分为高糖对照组、抑制剂组、抑制剂＋来氟米特（A771726）组、A771726组,将以上各组足细胞培养24h后,分别进行ERK1/2信号途径的检测同前及流式细胞仪检测足细胞的凋亡率。结果：高糖组30min可以活化ERK1/2蛋白,6h开始达高峰,持续活化到24h开始降至基础水平。正常糖及高渗对照组未能活化ERK1/2。与高糖组相比,ERK1/2蛋白抑制剂（PD98059）抑制了ERK1/2的磷酸化,使磷酸化的ERK1/2（P-ERK1/2）蛋白表达明显减少（P〈0.01）,从而影响了下游多种核转录因子的活化,影响目的基因的表达而增加了足细胞的凋亡（P〈0.01）。A771726可以增加P-ERK1/2的表达量（P〈0.01）,从而减少足细胞的凋亡（P〈0.05）。而PD98059可以影响A771726的作用,使其对足细胞的保护作用减弱,其凋亡率比高糖组明显增加（P〈0.01）。结论：ERK1/2信号途径参与了来氟米特对足细胞的保护作用。     

Simvastatin Reverses Podocyte Injury but not Mesangial Expansion in Early Stage Type 2 Diabetes Mellitus

Statins may confer renal protection in a variety of glomerular diseases, including diabetic nephropathy (DN). However, various glomerular lesions have different etiologies and may have different responses to statins. This study was performed to determine the differential effects of simvastatin (SMV) on glomerular pathology including mesangial expansion and podocyte injury in a mouse model of early stage type 2 diabetes mellitus (DM). Type 2 DM was induced in male C57BL/6 mice by feeding a high fat diet (HF; 45 kcal% fat). After 22 weeks, one group of HF mice was treated with SMV (HF-SMV; 7 μg/day/g BW) and another group was treated with vehicle (HF-vehicle) for 4 weeks via osmotic mini-pump. A third group served as age-matched normal diet vehicle controls (ND-vehicle; 10 kcal% fat). At the end of treatment, glomerular morphology was evaluated in a blind manner to determine the progression of DN. Body weight, blood glucose, insulin, HDL-cholesterol and triglycerides, but not LDL-cholesterol, were increased in HF mice. Over the course of treatment, the 24-hour urinary albumin excretion (UAE) was unchanged in ND-vehicle. HF mice exhibited elevated UAE, which decreased with SMV, but was unchanged with vehicle. The absolute mesangial volume and the relative mesangial volume per glomerular volume increased in HF-vehicle and remained elevated with SMV treatment. The immuno-staining of nephrin, a protein marker of the integrity of podocyte slit diaphragms, was decreased in HF-vehicle; however, the nephrin quantity of the HF-SMV group was not different from ND-vehicle. It is concluded that SMV reverses podocyte damage, but does not affect mesangial expansion in the kidneys of early stage proteinuria of type 2 DM.     

尿毒清颗粒对糖尿病大鼠足细胞损伤的保护作用研究

目的：探讨尿毒清颗粒对糖尿病大鼠足细胞损伤的保护作用。方法：将SD大鼠制备成STZ糖尿病模型,实验分3组：正常对照组、糖尿病未干预组、尿毒清颗粒治疗组（2.6g·kg-1·d-1灌胃）,于实验第4周、8周末检测血糖、血肌酐、尿肌酐及尿白蛋白排泄率,光镜、电镜下观察肾组织病理改变并计数足突宽度,免疫组化观察足细胞相关蛋白分子nepherin、podocin的表达,Real time-PCR检测肾皮质nepherin、podocin mRNA表达。结果：尿毒清颗粒可以改善糖尿病大鼠肌酐清除率,降低尿白蛋白排泄,改善肾脏病理,减轻足突融合,维持足细胞相关蛋白分子的分布与表达。结论：初步证实尿毒清颗粒能通过上调足细胞相关蛋白分子水平减轻足细胞损伤,对糖尿病大鼠足细胞损伤具有保护作用。     

脊髓背角COX-1和COX-2在p38MAPK诱发大鼠切口痛中的作用

目的 评价脊髓背角环氧化酶-1(COX-1)和COX-2在p38丝裂原活化蛋白激酶(p38MAPK)诱发大鼠切口痛中的作用.方法 雄性SD大鼠,体重250～300 g,选择鞘内置管成功的大鼠112只,随机分为4组(n=28):假手术组(S组)、切口痛组(IP组)、二甲基亚砜组(DMSO组)和p38MAPK特异性抑制剂SB203580组(SB203580组).S组鞘内注射0.9%生理盐水20 μl后,吸入异氟烷(呼气末浓度1.4%)min,不做手术;IP组术前10 min鞘内注射0.9%生理盐水20 μl;DMSO组和SB203580组术前10 min分别鞘内注射2%DMSO(SB203580的溶媒)10 μl和SB203580 30 μg(10 μl),然后用0.9%生理盐水10 μl冲洗导管.于鞘内置管后5 d,制备大鼠左后足切口痛模型.各组于术前1 h、术后2、3、6 h和1、2、3、5 d时,测定机械缩足反射阈值(MWT)和热刺激缩足反射潜伏期(TWL).各组于术后2、3、6 h和1、2、3、5 d痛阈测定结束后各处死4只大鼠,采用Western blotting法测定脊髓背角COX-1和COX-2的表达水平.结果 与S组比较,IP组和DMSO组术后2 h～2 d时MWT降低,术后2 h～3 d时TWL缩短,IP组、DMSO组和SB203580组术后3 h～3 d脊髓背角COX-1表达上调(P<0.05);与IP组和DMSO组比较,SB203580组术后2 h～1 d时MWT升高,术后2 h～2 d时TWL延长,术后6 h～2 d脊髓背角COX-1表达下调(P<0.05);4组术后各时点脊髓背角COX-2表达差异无统计学意义(P>0.05).结论 p38MAPK诱发大鼠切口痛与脊髓背角COX-1有关,与COX-2无关.     

Basal bone phenotype and increased anabolic responses to intermittent parathyroid hormone in healthy male COX-2 knockout mice

Cyclooxygenase-2 (COX-2) knockout (KO) mice in inbred strains can have renal dysfunction with secondary hyperparathyroidism (HPTH), making direct effects of COX-2 KO on bone difficult to assess. COX-2 KO mice in an outbred CD-1 background did not have renal dysfunction but still had two-fold elevated PTH compared to wild type (WT) mice. Compared to WT mice, KO mice had increased serum markers of bone turnover, decreased femoral bone mineral density (BMD) and cortical bone thickness, but no differences in trabecular bone volume by μCT or dynamic histomorphometry. Because PTH is a potent inducer of COX-2 and prostaglandin (PG) production, we examined the effects of COX-2 KO on bone responses after 3 weeks of intermittent PTH. Intermittent PTH increased femoral BMD and cortical bone area more in KO mice than in WT mice and increased trabecular bone volume in the distal femur in both WT and KO mice. Although not statistically significant, PTH-stimulated increases in trabecular bone tended to be greater in KO mice than in WT mice. PTH increased serum markers of bone formation and resorption more in KO than in WT mice but increased the ratio of osteoblastic surface-to-osteoclastic surface only in KO mice. PTH also increased femoral mineral apposition rates and bone formation rates in KO mice more than in WT mice. Acute mRNA responses to PTH of genes that might mediate some anabolic and catabolic effects of PTH tended to be greater in KO than WT mice. We conclude that (1) the basal bone phenotype in male COX-2 KO mice might reflect HPTH, COX-2 deficiency or both, and (2) increased responses to intermittent PTH in COX-2 KO mice, despite the presence of chronic HPTH, suggest that absence of COX-2 increased sensitivity to PTH. It is possible that manipulation of endogenous PGs could have important clinical implications for anabolic therapy with PTH.     

防己黄芪汤对阿霉素肾病大鼠蛋白尿及足细胞病变的影响

目的：探讨防己黄芪汤对蛋白尿及其发生原因——足细胞病变的影响。方法：采用阿霉素肾病大鼠造成肾病综合征模型。以防己黄芪汤、2倍剂量防已黄芪汤、防已黄芪去甘草汤灌胃。于14d、28d、42d测24h尿蛋白定量;实验42d取血、取肾,检测血生化,观察肾组织病理改变,免疫组织化学法、Western-blotting、RT-PCR检测肾组织nephrin、podoein蛋白及基因水平。结果：模型组大鼠蛋白尿明显增加,伴血Alb下降;与模型组比较,防己黄芪汤组大鼠尿蛋白定量在实验14d、28d、42d明显减少。2倍剂量防己黄芪汤组、防己黄芪去甘草汤组大鼠尿蛋白定量在42d明显减少。模型组大鼠nephrin蛋白表达上调,药物干预后表达明显下降;模型组podoein蛋白和基因表达下调,药物干预后表达明显增加。结论：防己黄芪汤明显改善阿霉素肾病大鼠蛋白尿,这可能与其对足细胞关键结构nephrin、podoein表达的调节有关。     

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.     

Mechanisms of Podocyte Injury in Diabetes: Role of Cytochrome P450 and NADPH Oxidases

OBJECTIVE

We investigated the role of cytochrome P450 of the 4A family (CYP4A), its metabolites, and NADPH oxidases both in reactive oxygen species (ROS) production and apoptosis of podocytes exposed to high glucose and in OVE26 mice, a model of type 1 diabetes.

RESEARCH DESIGN AND METHODS

Apoptosis, albuminuria, ROS generation, NADPH superoxide generation, CYP4A and Nox protein expression, and mRNA levels were measured in vitro and in vivo.

RESULTS

Exposure of mouse podocytes to high glucose resulted in apoptosis, with approximately one-third of the cells being apoptotic by 72 h. High-glucose treatment increased ROS generation and was associated with sequential upregulation of CYP4A and an increase in 20-hydroxyeicosatetraenoic acid (20-HETE) and Nox oxidases. This is consistent with the observation of delayed induction of NADPH oxidase activity by high glucose. The effects of high glucose on NADPH oxidase activity, Nox proteins and mRNA expression, and apoptosis were blocked by N-hydroxy-N′-(4-butyl-2-methylphenol) formamidine (HET0016), an inhibitor of CYP4A, and were mimicked by 20-HETE. CYP4A and Nox oxidase expression was upregulated in glomeruli of type 1 diabetic OVE26 mice. Treatment of OVE26 mice with HET0016 decreased NADPH oxidase activity and Nox1 and Nox4 protein expression and ameliorated apoptosis and albuminuria.

CONCLUSIONS

Generation of ROS by CYP4A monooxygenases, 20-HETE, and Nox oxidases is involved in podocyte apoptosis in vitro and in vivo. Inhibition of selected cytochrome P450 isoforms prevented podocyte apoptosis and reduced proteinuria in diabetes.Diabetic nephropathy in humans is characterized by increased urinary albumin excretion (microalbuminuria), which often progresses to proteinuria, one of the most important prognostic risk factors for kidney disease progression (1). Glomerular visceral epithelial cells, or podocytes, play a critical role in maintaining the structure and function of the glomerular filtration barrier. Careful morphometric analyses of renal biopsy in subjects with type 1 and type 2 diabetes (2–4) demonstrate that the density of podocytes is reduced not only in individuals with diabetic nephropathy, but also in patients with short duration of diabetes before the onset of microalbuminuria (4,5). Studies in experimental models of type 1 and type 2 diabetes have also documented that podocyte depletion represents one of the earliest cellular lesions affecting the diabetic kidney (6,7). Among various morphologic characteristics, the decreased number of podocytes in glomeruli is the strongest predictor of progression of diabetic nephropathy, where fewer cells predict more rapid progression (3,4). Although these observations identify podocyte depletion as one of the earliest cellular features of diabetic kidney disease, the mechanisms that underlie the loss of podocytes in diabetic nephropathy remain poorly understood.High glucose induces apoptosis (8), and there is evidence that podocyte apoptosis contributes to reduced podocyte number (9). High glucose, transforming growth factor-β (TGF-β), and angiotensin II (ANGII) induce apoptosis of cultured podocytes (9–12). ANGII appears to induce apoptosis in cultured rat glomerular epithelial cells at least partially via TGF-β because its apoptotic effect is attenuated by an anti–TGF-β antibody (12). There is also evidence that reactive oxygen species (ROS) contribute to podocyte apoptosis and depletion in cells exposed to high glucose and in experimental diabetic nephropathy (7). However, the sources of ROS and the kinetics of their generation have not been well characterized. We and others (13–15) have recently identified NADPH oxidases as major sources of ROS in kidney cortex and glomeruli of rats with type 1 diabetes. Six homologs of the cytochrome subunit of the phagocyte NADPH oxidase (Nox2/gp91^phox) have been cloned (16). At least three different Nox isoforms are expressed in the kidney cortex: Nox1, Nox2, and Nox4 (16). Cytochromes P450 (CYP450s) are significant sources of ROS in many tissues (17,18). CYP450 metabolizes arachidonic acid into hydroxyeicosatetraenoic acids (20-HETEs) and EETs (epoxyeicosatrienoic acids). 20-HETE, the ω-hydroxylation product of arachidonic acid, is one of the major CYP eicosanoids produced in the kidney cortex (19–21). The predominant CYP450 in the kidney cortex that synthesizes 20-HETE is cytochrome P450 of the 4A family (CYP4A) (19–21). 20-HETE has multiple and opposing functions depending on the site of production and target cells/tissues (19,22–24).In this study, we demonstrate that high glucose induces ROS production and apoptosis in cultured mouse podocytes through the upregulation of CYP4A with increased production of 20-HETE and upregulation of NADPH oxidases. Inhibition of 20-HETE production prevented podocyte apoptosis in vitro and decreased oxidative stress, podocyte apoptosis, and proteinuria in an in vivo model of type 1 diabetes.     

COX-1 and COX-2 expression in osteoid osteomas.

Osteoid osteoma is a benign bone forming neoplasm that is characterized by its small size (less than 2 cm), self-limited growth, and the tendency to cause extensive reactive changes in the adjacent tissue. The lesion classically presents with severe pain at night that is dramatically relieved by NSAIDs. The tumor has been shown to express very high levels of prostaglandins, particularly PGE2 and PGI2. The high local levels of these prostaglandins are presumed to be the cause of the intense pain seen in patients with this lesion. One generally accepted form of treatment is the prolonged use of NSAIDs. Since the cyclooxygenases are thought to be the source of these prostaglandins, and the central target of NSAIDs, we evaluated the expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in osteoid osteoma tissues from patients following surgery. In the 12 specimens examined we found that the tumor osteoblasts had strong immunohistochemical staining for COX-2, while the staining in the surrounding host osteoblasts in the reactive bone was scant. Significant COX-1 staining was also detected in both tumor and host osteoblasts. For comparison we examined the COX expression in human fracture callus, fibrous dysplasia, osteoblastoma, osteofibrous dysplasia, and myositis ossificans. With the exception of fracture callus, very limited amounts of COX-2 could be detected in these tissues. Taken together, we conclude that the increased production of prostaglandins by osteoid osteomas implicates that COX-2 is one of the mediators of this condition. These findings suggest that the newly selective COX-2 inhibitors could be used to more safely treat osteoid osteomas.     

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。     

尿足细胞及其相关分子在肾小球疾病中的表达

目的：探讨尿液检测局灶节段性肾小球硬化足细胞损伤与其他足细胞病之间的特点和差异。方法：入选原发性局灶节段性肾小球硬化（KSGS）患者54例,膜性肾病（MN）23例及微小病变（MCD）12例,正常对照20例。免疫荧光法计数尿足细胞,荧光实时定量PCR法定量尿沉渣足细胞相关分子nephrin、podocin、synaptopodin mRNA的表达水平,Western印迹法检测尿液WilmsTumor1（WT1）蛋白水平,免疫荧光法检测肾脏组织podocalyxin的表达及分布。结果：（1）FSGS组、MN组、MCD组和对照组尿足细胞阳性率分别是63％、34．8％、33．3％和0,FSGS组与其余各组相比差异均有统计学意义（P〈0．05）。FSGS组足细胞脱落数目显著高于MCD组、MN组和对照组（P〈0．05）,伴足细胞尿FSGS患者与不伴足细胞尿FS—GS患者相比,24h尿蛋白和血清白蛋白（Alb）差异均有统计学意义（P〈0．05）。（2）FSGS组尿沉渣足细胞nephrin mRNA表达水平显著高于MCD和MN组（P〈0．05）;FSGS组尿沉渣足细胞podocinmRNA表达显著高于MCD组（P〈0．05）,与MN组相比有升高趋势但差异无统计学意义;尿沉渣足细胞synaptopodin mRNA表达各组间差异无统计学意义。尿沉渣足细胞nephrin、podocin．synaptopodin mRNA的表达与24h蛋白尿无相关性。（3）FSGS组尿WT1蛋白量显著高于MCD和MN组。部分足细胞阴性患者尿液检测到WT1分子。（4）FSC-S患者肾组织podocalyxin较对照组、MCD和MN有明显的节段缺失。结论：局灶节段性肾小球硬化病患者足细胞损伤严重,尿足细胞与FSGS疾病活动相关。尿沉渣足细胞nephrin mRNA表达可以把FSGS与MCD和MN区分开来,尿WT1蛋白可能是足细胞早期损伤指标。