CD28/B7-1与儿童肾病综合征

CD28/B7-1是一对参与机体特异性免疫应答极其重要作用的分子.CD28主要存在于T淋巴细胞表面,而B7-1为CD28的配体之一,可表达于肾脏足突细胞.初步研究显示,B7-1分子参与了足突细胞病变的发生发展,而肾脏足突细胞参与了肾病综合征病理免疫反应过程,尤其在微小病变型肾病综合征中起主导作用.国内外学者已经着手相关动物实验及少量临床试验的研究,并取得一定成果.通过阻断CD28/B7-1信号而抑制肾病综合征的发生发展过程,将为儿童肾病综合征的临床治疗提供新的思路.     

狼疮肾炎患者自噬水平及其对足细胞相关蛋白表达水平的影响

目的探讨狼疮肾炎(lupus nephritis,LN)患者自噬水平及其对足细胞相关蛋白表达水平的影响。方法选择2017年5月至2019年5月于榆林市第一医院收治的69例LN患者为LN组,50例系统性红斑狼疮(systemic lupus erythematosus,SLE)患者为SLE组,50例肾切除手术患者为对照组,观察3组肾脏足细胞内自噬体数量,比较3组肾脏组织中自噬相关蛋白、微管相关蛋白轻链3(LC3)、B淋巴细胞瘤蛋白质-2-相互作用蛋白(Beclin1)的表达,以及足细胞相关蛋白,肾病蛋白(Nephrin)、足突蛋白(Podocin)的表达。分离狼疮肾炎患者肾脏足细胞,将足细胞分为自噬抑制组和自噬诱导组,自噬抑制组加入100 nmol/L 3-甲基腺嘌呤(3-MA),自噬诱导组加入100 nmol/L雷帕霉素(RAPA),比较3组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin等蛋白的表达。结果LN组、SLE组肾脏足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于对照组(P<0.05);SLE组肾脏足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于LN组(P<0.05);自噬诱导组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于正常对照组、自噬抑制组(P<0.05);正常对照组足细胞内自噬体数量及LC3、Beclin-1、Podocin、Nephrin蛋白表达量显著高于自噬抑制组(P<0.05)。结论LN患者自噬水平呈升高状态,自噬水平升高可能通过上调足细胞相关蛋白Podocin、Nephrin水平而减轻足细胞损伤,抑制LN病情进展。     

猪后肾帽状间充质细胞发育为肾小球足细胞的过程

目的:探讨中国实验用小型猪肾小球足细胞的发育过程。方法:应用过碘酸-希夫氏染色观察中国实验用小型猪胚胎不同时间点(胚胎28d至出生后21d,以周为单位,共17个时间点)肾小球发育过程中的形态学变化。应用免疫荧光技术检测猪胚肾不同阶段(帽状间充质、肾小囊体、逗号形体、"S"形体、毛细血管袢期肾小球、成熟肾小球)足细胞的发育过程。结果:猪在胚胎第28天(E28d)后肾已开始发育,可见典型的帽状间充质、肾小囊体、逗号形体和"S"形体;E35d可见肾小球形成,包括近皮质的不成熟肾小球以及近髓质的成熟肾小球。胚肾组织免疫荧光染色显示:胚肾早期足细胞标志物WT1表达于Six2阳性的后肾帽状间充质细胞,相继表达于肾小囊体、整个逗号形体、逗号形体尾部以及"S"形体下端,最终局限于肾小球足细胞。结论:中国实验用小型猪的足细胞来源于Six2阳性的后肾帽状间充质细胞,经过肾小囊体、逗号形体、"S"形体、毛细血管袢期肾小球阶段,发育成为成熟肾小球的足细胞。     

黄芪甲苷的抗氧化应激作用对体外高糖刺激足细胞的保护作用

目的:观察黄芪甲苷的抗氧化应激作用对体外高糖刺激下的足细胞的保护作用。方法:将条件性永生的小鼠足细胞随机分为正常对照组(NG)、高糖组(HG)、甘露醇高渗对照组(MA)、DMSO组及HG+不同剂量(5、15、30μg/ml)AS-IV干预组。采用CCK-8法检测各组足细胞活性,氧化应激试剂盒检测细胞中丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)水平;同时应用western印迹法检测细胞整合素连接激酶ILK蛋白表达量。结果:(1)足细胞活性:与NG组相比,MA组差异无统计学意义,HG组足细胞活性显著降低(P<0.05);与HG组相比,HG+30μg/mlAS-IV组足细胞活性显著升高(P<0.05),DMSO组、HG+15μg/mlAS-IV组和HG+5μg/mlAS-IV组差异无统计学意义(P<0.05)。(2)氧化应激及整合素连接激酶蛋白表达量:与NG组相比,HG组足细胞MDA含量升高,SOD、CAT和GSH-Px活性下降,ILK蛋白表达量下降(P<0.05)。与HG组相比,HG+30μg/mlAS-IV组MDA含量下降,SOD、CAT和GSH-Px活性升高,ILK蛋白表达量水平升高(P<0.05);HG+15μg/mlAS-IV组及HG+5μg/mlAS-IV组差异无统计学意义(P<0.05)。结论:黄芪甲苷(30μg/ml)的抗氧化应激作用对高糖诱导的足细胞损伤具有一定保护作用,可能与下调整合素连接激酶ILK系统有关。     

霉酚酸酯对微小病变肾病治疗作用研究

目的以阿霉素肾病大鼠建立微小病变肾病模型,以霉酚酸酯(MMF)进行干预,检测nephrin的表达,研究霉酚酸酯对微小病变肾病的治疗作用及其机制。方法SD大鼠18只,分为肾病模型组、MMF治疗组、对照组。模型组、治疗组大鼠尾静脉一次性注入阿霉素7.5mg/kg,治疗组大鼠于注药次日开始使用MMF20mg/(kg·d)灌胃。对照组大鼠尾静脉一次性注入等量生理盐水。每组于第28天各取大鼠6只,检测尿蛋白、血生化指标;并用免疫组化、Westernblot方法,检测肾组织内nephrin蛋白水平。结果肾病组尿蛋白第28天达高峰;血清清蛋白明显降低(P<0.01);治疗组第28天尿蛋白、血清甘油三酯、胆固醇较肾病组减少(P<0.01),血清清蛋白较肾病组增加(P<0.01)。免疫组化、Westernblot结果提示肾病组较对照组第28天nephrin蛋白表达升高(P<0.01);治疗组第28天nephrin蛋白表达较肾病组下调(P<0.01)。结论阿霉素诱发的微小病变肾病发生与nephrin表达异常有关,霉酚酸酯可以减少蛋白尿,延缓微小病变型大鼠肾损伤,其作用与影响nephrin的表达有关。     

Glucose transporters in diabetic nephropathy

Changes in glucose transporter expression in glomerular cells occur early in diabetes. These changes, especially the GLUT1 increase in mesangial cells, appear to play a pathogenic role in the development of ECM expansion and perhaps other features of diabetic nephropathy. In addition, it appears that at least some diabetic patients may be predisposed to nephropathy because of polymorphisms in their GLUT1 genes. GLUT1 overexpression leads to increased glucose metabolic flux which in turn triggers the polyol pathway and activation of PKC and 1. Activation of these PKC isoforms can lead directly to AP-1 induced increases in fibronectin expression and ECM accumulation. Other, more novel effects of GLUT1 on cellular hypertrophy and injury could also promote changes of diabetic nephropathy. Strategies to prevent GLUT1 overexpression could ameliorate or prevent the progression of diabetic nephropathy.     

Insulin-like growth factor binding protein-2 modulates podocyte mitogenesis

To study the role of insulin-like growth factors (IGF) in podocyte maturation, we isolated and characterized fetal visceral glomerular epithelial cells from human kidneys obtained at 8–18 weeks gestation. Cells were identified as podocyte lineage by their cobblestone morphology and immunoreactivity with synaptopodin, Wilms tumor-1 suppressor gene product (WT-1), complement receptor CR1, and cytoskeletal proteins smooth muscle actin and vimentin. Stimulation of the podocyte cell monolayers with IGF-II resulted in a slight increase in mitogenesis, an effect that was concentration and time dependent and abrogated by co-incubation with exogenous IGF binding protein 2 (IGFBP-2). Western blot analysis of conditioned media revealed that cultured podocytes expressed endogenous IGFBP-2 exclusively. IGF-II stimulation enhanced IGFBP-2 production in a dose- and time-dependent fashion and was associated with an increase in IGFBP-2 mRNA production. These data demonstrate that IGF-II-stimulated IGFBP-2 production appears to inhibit the mitogenic effect of IGF-II, and may have an autocrine effect on the maturation, differentiation, and survival of fetal podocytes.     

Expression of nephrin,podocin, α-actinin,and WT1 in children with nephrotic syndrome

Recently, nephrin, podocin, -actinin, and WT1, which are located at the slit diaphragm and expressed by the podocyte, were found to be causative in congenital/familial nephrotic syndrome (NS), but their role in acquired NS remains unclear. We studied their expression in NS with the aim of disclosing their possible role in the development of proteinuria. Immunofluorescence, confocal microscopy, and image analysis were used to study the expression and the distribution in 19 children with primary NS, 9 with isolated hematuria, and 9 controls. All the children with NS presented with heavy proteinuria and foot process effacement was identified by electron microscopy. No proteinuria and foot process effacement was seen in the group with hematuria. A dramatic decrease of podocin expression was found in NS (86.66±22.74) compared with control groups (P=0.014). Furthermore, we also found the pattern of distribution of nephrin, podocin, and -actinin changed in children with NS. In conclusion, a dramatic decrease of podocin expression and abnormal distribution of nephrin, podocin, and -actinin were found in children with NS. No differences were found in children with isolated hematuria, suggesting involvement of these molecules in the development of proteinuria in primary NS.     

Podocyte foot process broadening in experimental diabetic nephropathy: amelioration with renin-angiotensin blockade

Aims/hypothesis. Changes in podocyte number and morphology have been implicated in the pathogenesis of proteinuria and the progression of human and experimental kidney disease. This study sought to examine podocyte foot process and slit pore architecture in experimental diabetic nephropathy and to determine whether such changes were modified with renoprotective intervention by blockade of the renin-angiotensin system. Methods. The number of filtration slits per 100 μm of glomerular basement membrane was assessed by transmission electron microscopy and quantitated histomorphometrically in control animals and in rats with 24 weeks of streptozotocin-induced diabetes. Diabetic rats were either untreated or received the angiotensin converting enzyme inhibitor ramipril, or the angiotensin II type 1 receptor antagonist, valsartan. Results. When compared with control animals, diabetes was associated with a decrease in the number of slit pores per unit length of glomerular basement membrane, indicative of podocyte foot process broadening. Both ramipril and valsartan attenuated these ultrastructural changes to a similar degree. These differences remained after correcting for glomerular volume as a possible confounding variable. Conclusion/interpretation. Preservation of podocyte architecture could contribute to the renoprotective effects of renin-angiotensin system blockade in diabetic nephropathy. [Diabetologia (2001) 44: 878–882] Received: 19 January 2001 and in revised form: 28 March 2001