糖尿病肾病患者足细胞病变的临床病理特征

目的：研究2型糖尿病肾病患者肾小球足细胞病变，分析其与血糖控制、蛋白尿、肾功能及肾组织病理形态学改变之间的关系。方法：27例经肾穿刺活检明确诊断的2型糖尿病肾病。肾组织病理定量计数肾小球足细胞数。借助足细胞特定标志物WTl与肾小球基膜Ⅳ型胶原α3链(C—Ⅳα3)双套色荧光染色，用激光共聚焦荧光显微镜对肾小球足细胞进行准确的密度定量分析。结果：糖尿病肾病患者无论临床表现为微量白蛋白尿、蛋白尿(尿蛋白＜3．5g/24h)，还是大量蛋白尿(尿蛋白＞3．5g/24h)，均伴肾小球足细胞数目及密度的减少，其中以大量蛋白尿组最为显著，蛋白尿组次之，微量白蛋白尿组最轻。足细胞数目及其密度与尿蛋白量呈显著负相关(P＜0．01)。足细胞数目的减少还与肾小球病理改变相关，表现为肾小球K—W结节病变者其足细胞数明显少于肾小球弥漫系膜增生性病变者(P＜0．01)。此外，足细胞数减少严重者肾小球硬化以及血清肌酐水平升高的发生率均明显增高。结论：糖尿病肾病患者早期就表现出肾小球足细胞数目及其密度的减少，随着病变加重，这种变化愈发明显。足细胞病变不仅导致大量蛋白尿的发生，而且还与肾小球硬化和肾功能损伤的发生有关。     

Nephrin,podocin及α-actinin在小鼠肾小球足细胞系的表达与分布

目的 :探讨nephrin ,podocin及α actinin在小鼠肾小球足细胞系 (MPC5)的表达与分布 ,为进一步研究上述分子间的相互作用建立稳定的实验平台。　 方法 :培养小鼠MPC5,以γ 干扰素诱导在 33℃传代增生 ,继而在37℃培养两周使细胞分化成熟以用于实验研究。相差显微镜观察足细胞形态 ;免疫荧光染色观察nephrin ,podocin ,α actinin及WT1在足细胞的分布 ;RT PCR检测足细胞nephrin ,podocin及α actinin 4的mRNA ;免疫蛋白印迹检测nephrin ,podocin ,α actinin及WT1蛋白。　 结果 :成熟足细胞呈星形且有突起形成。免疫荧光及免疫蛋白印迹显示足细胞特异性的表达WT1分子。免疫荧光染色可见nephrin和podocin在足细胞内均呈线状分布于胞膜表面 ,α actinin呈细丝状分布于胞质内及伸出的突起中。在mRNA水平及蛋白水平均检测到nephrin ,podocin和α actinin 4表达 ,其蛋白大小分别为 180KDa,4 5KDa和 10 0KDa。　 结论 :首次在mRNA水平及蛋白水平证实了小鼠MPC5能够表达nephrin ,podocin及α actinin ,为进一步研究这些分子间的相互作用奠定了基础。     

阿米洛利抑制尿激酶受体表达及减少蛋白尿的机制

目的：观察阿米洛利在经典的5/6肾切除大鼠模型中对蛋白尿的影响,探讨其影响蛋白尿的机制。方法构建经典的5/6肾切除大鼠模型,实验分为3组：假手术对照组（Sham）、5/6肾切除组（NTX）、5/6肾切除+阿米洛利干预组（NTX+阿米洛利）。采用考马斯亮蓝法检测各组24 h尿蛋白,利用免疫荧光共聚焦、实时荧光定量PCR等技术,检测足细胞尿激酶受体（uPAR）蛋白和uPAR mRNA的表达情况。结果第2周时,与假手术对照组（Sham）相比较,5/6肾切除组（NTX）24 h尿蛋白明显升高（47.50±28.05 mg vs 14.28±3.8 mg,P=0.023）,有统计学意义;与NTX组相比,NTX+阿米洛利24 h尿蛋白无统计学意义（51.56±21.03 mg vs 47.50±28.05 mg,P=0.748）。第12周时,与NTX组（188.31±29.82）mg相比,NTX+阿米洛利组（121.37±31.14）mg、Sham组（21.32±8.59）mg 24 h尿蛋白增加量均进一步减少,具有统计学意义[P值分别为0.001,0.000]。激光共聚焦显微镜观察,与Sham组相比较,NTX组PLAUR mRNA表达明显增高（9.74±1.44 vs 1.01±0.13,P<0.01）,有统计学意义;与NTX组相比较, NTX+阿米洛利mRNA表达明显降低（9.74±1.44 vs 5.01±1.36,P<0.01）,有统计学意义。结论阿米洛利可能通过抑制受损足细胞uPAR的表达,从而起到降蛋白尿、延缓肾小球硬化的作用。     

活性维生素D3通过抑制TRPC6表达发挥糖尿病肾病的保护作用

目的:探讨活性维生素D3对链脲佐菌素(STZ)诱导糖尿病肾病(DN)大鼠的肾保护作用是否与抑制瞬时受体电位阳离子通道蛋白6(TRPC6)有关.方法:30只雄性SD大鼠随机分为正常对照组(NC组)、DN组及DN加活性维生素D3干预组(DN+ VD组)3组各10只.造模成功后6、12、18周检测大鼠体重、24 h尿蛋白量;造模成功后18周末处死大鼠,检测血样及肾组织指标变化.结果:DN+ VD组与DN组相比蛋白尿显著减少,肾脏病理损伤改善.DN组与NC组比较,Podocin、Nephrin蛋白表达量均明显降低(均P＜0.05),Desmin和TRPC6蛋白表达量均显著升高(均P＜0.05),活性维生素D3干预后上述改变明显改善,差异有统计学意义.相关性分析显示:TRPC6与Podocin(r=-0.808,P＜0.05)、Nephrin(r=-0.791,P＜0.05)呈负相关,而与24 h尿蛋白(r=0.886,P＜0.05)、Desmin(r=0.929,P＜0.05)呈正相关.结论:活性维生素D3显著抑制STZ诱导的糖尿病大鼠肾脏损伤,其作用机制与调节足细胞TRPC6的表达有关.     

The Renin-Angiotensin-aldosterone system in podocytes

The renin-angiotensin-aldosterone system (RAAS) plays a critical role in kidney function and its inhibition reduces proteinuria and preserves kidney function in patients with chronic kidney disease. Recent studies have shown that podocytes generate many components of the RAAS and they express receptors of RAAS, including angiotensin II, mineralocorticoid, and prorenin receptors. Crucial functions of podocytes, such as contraction, apoptosis, autophagocytosis, and cytoskeletal organization, have been shown to be regulated by the angiotensin II type 1 receptors. An activation of the glomerular RAAS and protection from podocyte injury by RAAS inhibitors have been shown in many glomerular diseases. Exploring the interaction between the local RAAS and the signaling involved in RAAS activation in podocytes will lead to new therapeutic strategies of podocyte protection.     

Fabry病的临床表现及肾脏病理学特征

目的 :探讨Fabry病患者临床表现及肾组织形态学特点。　 方法 :总结 9例Fabry病患者临床表现和肾组织形态学特点。同时对肾小球足细胞数定量分析 ,并借助足细胞特殊标记物WT1对足细胞的密度及其缺失分布特点进行观察。　 结果 :①患者以年轻男性为主 ,多有肾脏病家族史。②多伴有Fabry病肾外表现 ,表现为皮肤血管角质瘤、少汗、低热、肢端感觉异常等症状。心脏受累发生率较高 ,多表现为房室传导阻滞、PR间期缩短、ST段和T波的异常、左心室高电压等。③均无明显角膜混浊、视网膜动脉曲张等Fabry病常见眼部病变。④肾脏病变表现为轻至中度蛋白尿。部分患者伴轻微镜下血尿。肾小管间质损伤较突出。⑤肾组织形态学改变表现为光镜下肾小球足细胞弥漫空泡变性 ;甲苯胺蓝染色显示足细胞浆内含大量嗜甲苯胺蓝的蓝色颗粒状物 ;电镜下嗜锇性、同心圆样髓样小体在胞浆中堆积。多数患者小管间质中重度病变。肾间质血管病变现象较为突出。⑥肾小球足细胞计数及足细胞密度均明显低于正常 (P <0 0 1) ,WT1表达缺失呈节段分布 ,缺失部位多位于周边袢和有节段硬化病变处。　 结论 :①Fabry病以男性青年多见 ,多有肾脏损害的家族史。②多数患者存在肾外表现 ,心脏病变发生率较高。③无明显Fabry病特征性眼部病变 ,无明显     

Adrenomedullin protects against oxidative stress-induced podocyte injury as an endogenous antioxidant.

BACKGROUND: We previously reported that puromycin aminonucleoside (PAN) increased adrenomedullin (AM) secretion and AM mRNA expression in podocytes, through overproduction of oxidative stress. To clarify the cytoprotective role of AM as antioxidative and antiapoptotic substance in podocytes, we investigated the effect of exogenous AM and AM antagonist on PAN-induced apoptosis in conditionally immortalized murine podocytes. METHODS: The expression of AM, RAMP 2 and RAMP 3 was investigated using real-time PCR, western blotting analysis and immunofluorescence microscopy. Reactive oxygen species (ROS) production was measured by CM-H(2)DCFDA fluorescence intensity method. The percentage of apoptotic cells was measured by Hoechst 33342 staining. RESULTS: PAN (100 microg/ml) significantly (P < 0.01) increased ROS production, associated with an increase in apoptosis; the percentage of apoptotic cells is 5.3% + 0.05% (P < 0.01) with 36 h treatment of PAN compared to 0.24 + 0.16% with no treatment. Several antioxidants could markedly reduce PAN-induced apoptosis in cultured podocytes, suggesting that PAN-induced apoptosis might be attributable to the overproduction of ROS. Accordingly, the administration of exogenous AM (10(-6) M) could significantly reduce not only ROS production via a PKA-dependent pathway, but also the resultant apoptosis induced by PAN. AM antagonists, CGRP8-37, augmented PAN-induced apoptosis, associated with increased ROS production, 2.2- and 2.3-Fold, respectively. RAMP 2 and RAMP 3 could be detected in podocytes and glomeruli. CONCLUSIONS: This suggests that ROS-induced up-regulation of AM with PAN could counteract ROS-induced apoptosis, by the suppression of ROS production. Therefore, AM might have the endogenous antioxidant potential to protect against ROS-induced podocyte injury.     

Increase of Integrin-Linked Kinase Activity in Cultured Podocytes upon Stimulation with Plasma from Patients with Recurrent FSGS

Recurrent focal segmental glomerulosclerosis (FSGS) is a major challenge in the field of transplantation. Integrin-linked kinase (ILK) has emerged as a key mediator of podocyte–glomerular basement membrane (GBM) interactions. To clarify the involvement of plasma factors in FSGS recurrence, we examined the effects of plasma from FSGS patients with or without posttransplant recurrence on cultured podocytes, focusing particularly on ILK activity. Podocytes from a conditionally immortalized mouse podocyte cell line were treated with plasma from 11 FSGS patients, and ILK activity was determined using an immune complex kinase assay. Treatment with plasma from three patients with recurrence induced an increase in ILK activity. In contrast, no increase in ILK activity was observed in cultured podocytes treated with plasma from the remaining three patients with recurrence and five patients without recurrence. Cultured podocytes treated with plasma that induced ILK activity showed alterations of focal contact and detachment from the laminin matrix. In conclusion, this preliminary study provides experimental evidence suggesting the possible presence of circulating toxic factors in the plasma of some patients with recurrent FSGS, which induce an increase in podocyte ILK activity that may lead to the detachment of podocytes from the GBM.     

WT1 mutation and podocyte molecular expression in a Chinese Frasier syndrome patient

We report on a Chinese girl with Frasier syndrome (FS). She presented with steroid-resistant focal segmental glomerulosclerosis (FSGS) and male pseudohermaphroditism. The WT1 IVS 9  +  5 G>A mutation was detected in one allele in the proband. The ratio of +KTS/−KTS was 0.67 in the proband’s cDNA. The expression of podocyte molecules (WT1, nephrin, podocin, α-actinin 4 and CD2AP) were also investigated in a renal specimen of this FS patient. WT1 expression showed diffuse nuclear staining, with less obvious speckles in the patient’s glomeruli than in those of controls. The distribution and intensity of podocyte molecules were altered both in normal- and abnormal-appearing glomeruli. In conclusion, the study presented a case of FS by clinical manifestation, renal pathology, karyotype analysis and genetic testing. A lower ratio of +KTS/−KTS and an abnormal distribution of WT1, as well as abnormal expressions of other podocyte molecules, were also revealed. The mechanisms of WT1 mutation causing FS still need to be investigated. Jianguo Li and Dan Zhao contributed equally to this work.     

晚期糖基化终产物对足细胞内肾素-血管紧张素系统的影响

目的 观察晚期糖基化终产物(advanced glycation end products,AGEs)对足细胞内肾素-血管紧张素系统(renin-angiotensin system,RAS)的影响及作用机制.方法 不同浓度的AGEs干预小鼠足细胞24h,分别检测肾素(renin)、血管紧张素原(renin-angiotensin system,AGT)、血管紧张素Ⅱ1型、2型受体(AT1R、AT2R)的表达,血管紧张素转换酶(angiotensin-converting enzyme,ACE)的活性和血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)的浓度,观察蛋白激酶B(Akt)的磷酸化,然后分别加入磷酸肌醇3激酶抑制剂LY294002、Iosartan、captopril和chymastatin,观察足细胞粘附性的变化.结果 与对照组相比,AGEs(80 μg/mL)明显上调AGT和AT1R的表达[(183.0±19.0)％ vs 100％,(179.0±17.0)％ vs100％,P＜0.05],裂解液中ACE活性明显增加[(142.8 ±10.3)U/μgvs (85.0 ±9.2)U/μg,P＜0.05],细胞上清中AngⅡ的浓度明显增加[(11.2±0.8) pg/mL vs(7.0±0.7)pg/mL,P＜0.05];Akt的磷酸化上调100％ (P ＜0.05),而LY294002可减轻AGEs介导的足细胞内RAS的激活;与AGEs组相比,LY294002可改善AGEs介导的足细胞粘附性的下降[(82±13)％ vs (40±12)％;(78±14)％vs(42±13)％,P＜0.05].结论 AGEs可能通过磷酸肌醇3激酶途径激活足细胞内的RAS,降低足细胞粘附性.