Vascular endothelial growth factor is an essential molecule for mouse kidney development: glomerulogenesis and nephrogenesis.

Homeostasis of body fluid is maintained by the kidneys, which contain two million glomeruli for blood filtration. A glomerulus is formed by growth of Bowman's capsule harmonized with a capillary during kidney development. The vascular endothelial growth factor (VEGF) is an essential angiogenic cytokine, and VEGF deficiency is known to be fatal in mice in early embryonic stages. As secretions of VEGF from cultured kidneys vary according to developmental stages, the role of VEGF in kidney development was studied in vivo by blocking the endogenous VEGF activity with antibody in newborn mice, in which most organs are already developed but kidneys are still developing. The antibody-treated animals showed normal growth but systemic edema. Vessel formation in the superficial renal cortex was disturbed, nephrogenic areas were diminished, and the number of developing nephrons decreased significantly. Many abnormal glomeruli, lacking capillary tufts, were observed in the antibody-treated mice, and VEGF expression in their Bowman's capsule showed a compensatory increase. These results suggest that VEGF mediates communication between the Bowman's capsule and capillary endothelial cells for developing a glomerulus as well as promoting nephrogenesis. In conclusion, VEGF is likely to be an essential molecule for kidney development, and especially for glomerulogenesis.     

Quantitative analysis of gene expressions of vascular endothelial growth factor-related factors and their receptors in renal cell carcinoma

Vascular endothelial growth factor (VEGF)-related factors are believed to regulate angiogenesis, an essential event in the growth of solid tumors. In this study, we investigated the expression of VEGF-related factor genes (VEGF, VEGF-B, and VEGF-C) and their receptor genes (VEGFR-1 and VEGFR-2) in renal cell carcinoma (RCC). There were significant differences in the expression level of VEGF, VEGFR-1 and VEGFR-2 between RCC and the corresponding normal renal tissue. The expression level of VEGF in the tumor tissue significantly correlated with those of VEGFR-1 and VEGFR-2. Expression levels VEGF-B and VEGF-C genes were not significantly different between RCC and normal renal tissue. A moderate to high protein expression for VEGF, VEGFR-1, and VEGFR-2 was observed in both the tumor cells and the endothelial cells, whereas the protein expression was low for VEGF-B and VEGF-C. The present results suggested that VEGF and its receptors VEGFR-1 and VEGFR-2 cooperates to play a crucial role in the angiogenesis of RCC, while VEGF-B and VEGFR-C may not. Furthermore, since VEGFR-1 and VEGFR-2 proteins were expressed in the tumor cells as well as in the endothelial cells, these receptors may also be responsible for the progression of RCC.     

Insuffisance rénale aiguë et prééclampsie

During pregnancy, acute renal failure is mostly represented by preeclampsia (PE) and HELLP (Hemolysis, elevated liver enzymes, low platelets) syndrome. During PE, several angiogenic factors including the vascular endothelial growth factor (VEGF) present failing functions. Recent studies highlighted the role of the soluble fms-like tyrosine kinase-1, a circulating factor that inhibits VEGF binding to its endothelial receptor, leading to placenta ischemia and acute kidney injury.Astrict control of diastolic blood pressure along with early fluid administration must be quickly started to avoid development of renal failure. To date, medical delivery is indicated in complicated PE and represents the only treatment allowing the reversal of the glomerular endothelopathy. Long-term follow-up of PE women highlights that PE is a cardiovascular risk factor as well as a risk of subsequent nephropathy. In that setting, proteinuria during pregnancy or in the peripartum period indicates additional kidney investigations.     

Glomerular endothelial cells are maintained by vascular endothelial growth factor in the adult kidney.

Vascular endothelial growth factor (VEGF) is known to maintain endothelial cells of immature vessels and is constitutively expressed in the kidney from the embryo to adult. We tested the hypothesis that VEGF activity is needed to maintain glomerular endothelial cells in the adult. Neutralizing antibody to VEGF165 was intraperitoneally administered to mice for 3 days to strongly suppress its intrinsic activity. On the fourth day, mice were sacrificed and tissues were examined by light and electron microscopies. Vascular casts of renal vessels were observed by a scanning electron microscopy. Distribution of the administered antibody and expressions of VEGF and Flk-1 were examined immunohistochemically. The suppression of endogenous VEGF activity caused swelling and vacuolation of endothelial cells and obstruction of capillaries in the glomerulus. Other tissues were not impaired significantly. The administered antibody was specifically localized to the glomerulus, and was found more predominantly in the juxta-medullary than in the cortical glomerulus. This pattern of antibody deposition was similar to that of Flk-1. VEGF expression in the glomerulus was compensatively elevated by the antibody treatment. These results show that demand for VEGF signaling in the glomerulus is much higher than in other tissues, probably to protect its endothelial cells against high tension for blood filtration. This demand may be fulfilled by enriched signaling through the Flk-1 in the glomerulus.     

Patterns of expression of vascular endothelial growth factor (VEGF) and VEGF receptors in mice suggest a role in hormonally regulated angiogenesis.

Vascular endothelial growth factor (VEGF) is a secreted endothelial cell-specific mitogen. To evaluate whether VEGF may play a role in angiogenesis, we have determined the spatial and temporal patterns of expression of VEGF and VEGF receptors during natural angiogenic processes taking place within the female reproductive system. Four angiogenic processes were analyzed: neovascularization of ovarian follicles, neovascularization of the corpus luteum, repair of endometrial vessels, and angiogenesis in embryonic implantation sites. During all processes, VEGF mRNA was found to be expressed in cells surrounding the expanding vasculature. VEGF was predominantly produced in tissues that acquire new capillary networks (theca layers, lutein cells, endometrial stroma, and the maternal decidua, respectively). VEGF-binding activity, on the other hand, was found on endothelial cells of both quiescent and proliferating blood vessels. These findings are consistent with a role for VEGF in the targeting of angiogenic responses to specific areas. Using in situ hybridization, we show that VEGF is expressed in 10 different steroidogenic and/or steroid-responsive cell types (theca, cumulus, granulosa, lutein, oviductal epithelium, endometrial stroma, decidua, giant trophoblast cells, adrenal cortex, and Leydig cells). Furthermore, in some cells upregulation of VEGF expression is concurrent with the acquisition of steroidogenic activity, and expression in other cell types is restricted to a particular stage of the ovarian cycle. These findings suggest that expression of VEGF is hormonally regulated. We propose that excessive expression of VEGF during gonadotropin-induced ovulation may contribute to the development of ovarian hyperstimulation syndromes by virtue of the vascular permeabilization activity of this factor.     

The related FLT4, FLT1, and KDR receptor tyrosine kinases show distinct expression patterns in human fetal endothelial cells

The growth factor receptors expressed on endothelial cells are of special interest because of their potential to program endothelial cell growth and differentiation during development and neovascularization in various pathological states, such as wound healing and angiogenesis associated with tumorigenesis. Vascular endothelial growth factor ([VEGF] also known as vascular permeability factor) is a potent mitogen and permeability factor, which has been suggested to play a role in embryonic and tumor angiogenesis. The newly cloned FLT4 receptor tyrosine kinase gene encodes a protein related to the VEGF receptors FLT1 and KDR/FLK-1. We have here studied the expression of FLT4 and the other two members of this receptor family in human fetal tissues by Northern and in situ hybridization. These results were also compared with the sites of expression of VEGF and the related placenta growth factor (PlGF). Our results reveal FLT4 mRNA expression in vascular endothelial cells in developing vessels of several organs. A comparison of FLT4, FLT1 and KDR/FLK-1 receptor mRNA signals shows overlapping, but distinct expression patterns in the tissues studied. Certain endothelia lack one or two of the three receptor mRNAs. These data suggest that the receptor tyrosine kinases encoded by the FLT gene family may have distinct functions in the regulation of the growth/differentiation of blood vessels.     

Expression of vascular endothelial growth factor in renal cell carcinoma is correlated with cancer advancement

Vascular endothelial growth factor (VEGF) functions as a regulator of neovascularization in malignant cells. VEGF as a mitogen is thought to alter renal cell carcinoma formation and tumor progression. We investigated the expression of the VEGF gene in order to evaluate its clinical significance in renal cell carcinoma. Tissue samples from 198 patients with renal cell carcinoma were examined with an immunohistochemical stain for the expression of the VEGF gene. The expression rate was compared to 34 normal renal cortical samples obtained from renal surgery from noncancer patients. There were significant differences between normal renal cortex (0%) and cancer tissue (54.5%) in positive staining of VEGF protein (P<0.001). With the progression of tumor grade, the positive rate of VEGF gene expression significantly increased. The expression rate of the VEGF gene in the advanced group, such as with lymph node involvement or vein invasion, was greater than that in the locally confined group (P<0.001). The results revealed that expression of the VEGF gene is proportional to the formation and progression of renal cell carcinoma, which may allow VEGF to be used as a prognostic marker for renal cell carcinoma.     

小肾癌4D THRIVE动态增强扫描参数与肿瘤血管生成的相关性研究

目的：探讨小肾癌4D THRIVE动态增强扫描参数与肿瘤血管生成的关系。方法：对30例临床疑似小肾癌患者进行4D THRIVE动态增强扫描,分别计算肿瘤感兴趣区（ROI）及瘤周正常肾组织的动态增强参数：最大增强斜率（Smax）、增强峰值（PH）及峰值时间（Tpeak）。病理标本进行免疫组织化学染色,测定微血管密度（MVD）计数和血管内皮生长因子（VEGF）表达,评价小肾癌各动态增强参数与MVD、VEGF的相关性。结果：小肾癌动态增强参数Smax（r=0.707,P＜0.01）、PH（r=0.687,P＜0.01）与MVD表达呈正相关,Tpeak（r=-0.413,P＜0.05）与MVD表达呈负相关。小肾癌MVD计数（63.07±14.73）个/视野,高于瘤周正常肾组织（P=0.002）;67％（20/30）的小肾癌VEGF表达阳性,高于瘤周正常肾组织（P=0.001）。结论：小肾癌4D THRIVE动态增强扫描部分参数与MVD、VEGF相关,在评价小肾癌血管生成方面有重要价值。     

西罗莫司对慢性移植肾肾病肾组织转化生长因子β1和血管内皮生长因子表达的影响(英文)

背景:西罗莫司对肾移植术后急性排斥反应的防治产生重要作用,同时,有研究发现它可抑制血管平滑肌细胞的增殖和迁徙,对慢性排斥反应以及慢性移植肾肾病产生防治作用,但具体的机制尚不清楚.目的:探讨西罗莫司对慢性移植肾肾病肾组织转化生长因子和血管内皮生长因子表达的影响.方法:选择原发性肾病首次尸肾移植者60例,随机分为两组:西罗莫司组和硫唑嘌呤组各30例,分别采用西罗莫司+环孢素A+激素,硫唑嘌呤+环孢素A+激素治疗,西罗莫司首次负荷剂量为6mg,2周内2mg/d,2周后改为1.0～2.0 mg/d,环孢素A为5.0～7.0 mg/d,硫唑嘌呤为50～100 mg/d,激素为15～0 mg/d.术后2年时,对移植肾进行活检.观察移植肾组织转化生长因子β1和血管内皮生长因子表达情况,并观察肝功能、血肌酐浓度、急性排斥反应发生率、人/肾存活率.结果与结论:随访2年,西罗莫司组于术后1,3,12个月的环孢素剂量明显低于硫唑嘌呤组,但是两组之间的血环孢素A的谷值浓度没有明显差异.硫唑嘌呤组中,转化生长因子β1表达主要分布于近曲小管,部分可见肾小球以及间质血管;大部分移植肾组织近曲小管呈阳性表达,线型分布于刷状缘,部分呈阳性表达.部分患者肾小球脏层上皮细胞呈节段性阳性表达.内皮细胞及系膜偶见阳性表达.西罗莫司组中,转化生长因子β1在近曲小管的表达则明显减弱,肾小球和间质血管无明显改变.硫唑嘌呤组中血管内皮生长因子表达主要见于肾小球脏层上皮细胞,部分病例也可见于内皮细胞及系膜细胞,间质血管呈阳性表达,主要分布于内皮层.西罗莫司组,肾小球、间质血管染色均明显减少.与硫唑嘌呤组比较,西罗莫司组人/肾存活率高、移植肾组织转化生长因子β1和血管内皮生长因子表达明显降低.结果表明,西罗莫司可降低移植肾组织转化生长因子β1和血管内皮生长因子表达,减缓慢性移植肾肾病的进展,延长移植肾存活时间.     

肾衰泻浊汤对肾衰竭大鼠内皮细胞损伤的保护

背景:肾衰泻浊汤临床治疗以泻浊解毒、补益脾肾为主。目的:观察肾衰泻浊汤对慢性肾衰竭模型大鼠肾脏局部血管内皮细胞损伤的保护和对血管内皮生长因子受体表达的调控作用。方法:将60只Wistar大鼠随机分为正常对照组、模型组、中药低剂量组、中药中剂量组、中药高剂量组、氯沙坦钾组,后5组以腺嘌呤诱导建立慢性肾衰竭动物模型,中药低、中、高剂量组分别灌胃给予6,12,24g/(kg·d)肾衰泻浊汤,氯沙坦钾组给予氯沙坦钾。结果与结论:与模型组比较,各治疗组大鼠血肌酐、尿素氮及血β2-微球蛋白、尿微量白蛋白、血清可溶性细胞间黏附因子1、血管内皮生长因子、因子Ⅷ相关抗原、肾脏指数显著减少(P<0.05),且血β2-微球蛋白、尿微量白蛋白与血肌酐、尿素氮呈显著正相关性。各治疗组大鼠肾组织损伤明显减轻,以中药中剂量组、氯沙坦钾组损伤最轻。表明肾衰泻浊汤能降低慢性肾衰竭大鼠血肌酐、尿素氮及血β2-微球蛋白、尿微量白蛋白水平,延缓慢性肾衰进展,其作用机制可能与调节可溶性细胞间黏附因子1、血管内皮生长因子、因子Ⅷ相关抗原有关。     

趋化因子受体4和血管内皮生长因子在肾癌中的表达及其临床意义

目的 探讨趋化因子受体4(CXCR4)和血管内皮生长因子(VEGF)在肾癌的发生、发展中的作用及临床意义.方法 采用免疫组织化学技术SP法检测CXCR4和VEGF在56例肾癌标本(包括20例伴有淋巴结转移的肾癌组织及肾周转移的淋巴结)、10例癌旁正常组织中的表达.结果 56例肾细胞癌组织中CXCR4、VEGF的表达阳性率分别为66.1%(37/56),73.2%(41/56),明显高于正常肾组织的表达阳性率20.0%(2/10)、30.0%(3/10),两者间差异有统计学意义(P＜0.05＝.肾癌组织中CXCR4和VEGF的表达呈正相关(r=0.315,P＜0.05＝,CXCR4和VEGF的表达与肾细胞癌的分期(χ2=9.520,P=0.023;χ2=9.072,P=0.027),肿瘤的侵袭转移(χ2=4.972,P=0.026;χ2=3.910,P=0.034)及微血管密度(P＜0.05＝有关,与患者的性别(χ2=0.020,P=0.887;χ2=0.001,P=0.716)、肿瘤的大小(χ2=0.003,P=0.995;χ2=0.108,P=0.990)、病理类型(χ2=1.960,P=0.900;χ2=0.112,P=0.994)无关.结论 CXCR4和VEGF在肾癌中呈高表达并且表达呈正相关,与肾癌的发展转移及预后密切相关.可以作为判断肾癌的侵袭转移及预后的重要指标,并给肾癌的治疗提供前景.

Abstract：

Objective To study the role and clinical significance of chemokine receptor-4 (CXCR4) and vascular endothelial growth factor (VEGF) in the occurrence and development of renal cell carcinoma. Methods Expression of CXCR4 and VEGF were detected by SP immunohistochemical technique in 56 cases of kidney carcinoma tissues (including 20 cases of lymph node metastasis), 10 normal tissues nearby kidney cancer. Results The positive rates of CXCR4 and VEGF were 66. 1% (37/56) and 73. 2% (41/56),which were significantly higher than those in normal tissues( 20. 0% (2/10) and 30. 0% (3/10), respectively) (P ＜ 0. 05 ＝. The expression of CXCR4 protein was significantly positively correlated with that of VEGF protein (r = 0. 315 ,P ＜ 0.05 ＝ in renal cell carcinoma. The expression of CXCR4 and VEGF was closely related to stages of tumor ( χ2 = 9. 520, P = 0. 023; χ2 = 9. 072, P = 0. 027 ), lymphatic metastasis, degree of invasion ( χ2 =4. 972, P = 0. 026; χ2 = 3.910, P = 0. 034 ), and microvessel density ( MVD) ( P ＜ 0. 05 ＝. However, they were not related to sex ( χ2 = 0. 020, P= 0. 887; χ2 = 0. 001, P = 0. 716 ), tumor size ( χ2 = 0. 003, P = 0. 995; χ2 =0. 108, P = 0. 990) and pathologic types ( χ2 = 1. 960, P = 0. 900; χ2 = 0. 112, P = 0. 994). Conclusion There is a significant positive correlation between high expressions of CXCR4 and VEGF proteins in renal cell carcinoma,the high expressions of CXCR4 and VEGF proteins may be related to the metastasis and prognosis of renal cell carcinoma,thus they could be used as important indicators in judging the metastasis prognosis of renal cell carcinoma,and offer prospects for the treatment of renal cell carcinona.     

The critical role of vascular endothelial growth factor in pulmonary vascular remodeling after lung injury

The pulmonary vascular endothelial cell plays a crucial role in the regulation of the pulmonary vascular tone and in the maintenance of the barrier function and integrity of the alveolar-capillary membrane. It also plays a major role in coagulation, fibrinolysis, and angiogenesis and participates in inflammatory reactions. Vascular endothelial growth factor (VEGF) is a central growth and survival factor for the endothelial cell. Particularly high levels of VEGF are expressed in the lungs, reflecting the critical role of VEGF for lung development and structural integrity of the adult lung. Vascular endothelial growth factor exerts a variety of physiological and pathophysiological actions in the lung. Recent evidence suggests its involvement in the pathogenesis of lung diseases such as bronchopulmonary dysplasia, acute lung injury, emphysema, and pulmonary hypertension. To summarize the critical effects of VEGF on the pulmonary endothelial cell in the pathogenesis of these diseases, the purposes of this review are to (1) discuss the biological activities and intracellular signaling pathways of VEGF in the lung; (2) summarize the regulatory mechanisms involved in VEGF expression; (3)address the effects of VEGF on endothelial cells in hyperoxia-induced and other forms of lung injury; (4) highlight the endothelial effects of VEGF in the pathogenesis of emphysema; and (5) explore the role of VEGF in the pathogenesis of pulmonary arterial hypertension.     

Increased macrophage infiltration and fractalkine expression in cisplatin-induced acute renal failure in mice

Inflammatory mechanisms contribute to cisplatin-induced acute renal failure (CisARF). Our first aim was to determine renal macrophage infiltration in CisARF. A more than 2-fold increase in CD11b-positive macrophages in the kidney on day 2 preceded the increase in blood urea nitrogen (BUN) and serum creatinine (SCr). Our next aim was to determine the chemoattractant for macrophage infiltration in CisARF. Fractalkine (CX(3)CL1) is expressed on activated endothelial cells and is a potent chemoattractant for macrophages that express its receptor (CX(3)CR1). Immunoblotting showed that whole-kidney CX(3)CL1 expression on days 1, 2, and 3 after cisplatin administration was increased. On immunofluorescence, the intensity of renal endothelial staining of CX(3)CL1 in blood vessels was significantly increased on day 2. Circulating von Willebrand factor (vWF), a measure of systemic endothelial injury, was increased on day 2. Next we determined whether macrophages played an injurious role in CisARF. Macrophages were depleted with injections of liposome-encapsulated clodronate (LEC). LEC resulted in a decrease in renal CD11b-positive macrophages on day 3. However, LEC-treated mice were not protected from CisARF on day 3. To determine the role of CX(3)CR1, both a specific anti-CX(3) CR1 antibody and CX(3) CR1(-/-) mice were used. Administration of the CX(3)CR1 antibody and CX(3) CR1(-/-) mice was not protected against CisARF. In summary, in CisARF, macrophage infiltration in the kidney, CX(3)CL1 expression in whole kidney and blood vessels, and the increase in circulating vWF precede BUN and SCr increase. However, inhibition of macrophage infiltration in the kidney or CX(3)CR1 blockade is not sufficient to prevent CisARF.     

血管内皮生长因子与单侧输尿管梗阻大鼠肾间质纤维化程度的相关性研究

目的观察单侧输尿管梗阻大鼠肾组织中血管内皮细胞生长因子(VEGF)的表达水平,并探讨VEGF与肾间质纤维化的相关性。方法将42只雄性SD大鼠按照随机原则分为假手术组和单侧输尿管梗阻模型组(UUO组),每组21只大鼠。术后第5、15、25天2组各处死7只大鼠,采集血清和24 h尿液,检测血肌酐、尿素氮、24 h尿蛋白定量,留取梗阻侧肾脏进行病理学检查,使用免疫组织化学方法检测VEGF在肾组织的表达水平,观察VEGF表达水平与肾间质纤维化程度及肾功能的相关性。结果术后第5、15、25天,UUO组血肌酐水平与同期假手术组相比明显升高,差异均有统计学意义(P<0.05);术后第5、15天,UUO组尿素氮水平高于同期假手术组,差异有统计学意义(P<0.05)。术后第5天UUO组24 h尿蛋白定量与假手术组比较,差异无统计学意义(P>0.05),但术后第15、25天24 h尿蛋白定量均高于假手术组,差异有统计学意义(P<0.05)。病理学检查结果显示,假手术组大鼠在术后第5、15、25天,肾小管上皮细胞可见较多VEGF蛋白表达;UUO组大鼠术后第5天肾小管间质开始出现少量炎性细胞浸润,少数肾小管出现扩张,部分肾小管可见VEGF蛋白表达,第15、25天肾小管间质见较多炎性细胞浸润,VEFG蛋白表达量呈逐渐降低趋势,术后第25天大量炎性细胞浸润,仅见少许肾小管VEGF呈弱表达,肾间质纤维化区域无VEGF表达。在UUO组中,术后第5天VEGF表达与24 h尿蛋白定量呈正相关(P<0.05);在术后第5、15、25天,VEGF的表达与血肌酐及尿素氮水平均无明显相关性(P>0.05)。结论在单侧输尿管梗阻大鼠肾间质纤维化模型中,VEGF表达量随肾间质纤维化程度加重逐渐减低,肾间质弥散性纤维化时,肾组织的VEGF几乎无表达,提示VEGF在肾间质纤维化发生发展中可能起重要作用。     

Clinical implication of urine test for markers of endothelial dysfunction and angiogenesis factors in assessment of tubulointerstitial fibrosis in chronic glomerulonephritis

AIM: To evaluate contribution of endothelial dysfunction and impairment of endothelial proliferation/ regeneration to mechanisms of development of tubulointerstitial fibrosis (TIF) in chronic glomerulonephritis (CGN) basing on urinary levels of markers of endothelial activation/impairment and angiogenesis factors. MATERIAL AND METHODS: A total of 67 CGN patients entered the study: 19 patients with moderate urinary syndrome (group 1), 37 patients with nephrotic syndrome (group 2), 11 patients with nephrotic syndrome and persistent renal failure (RF). A control group consisted of 12 healthy subjects. The examination covered excretion with urine of Willebrand factor (WF), plasminogen activator inhibitor I (PAL-I), fibrin degradation products (FDP), vascular endothelial growth factor (VEGF). These values were compared with severity of fibrous changes in renal interstitium estimated by biopsy morphometry. RESULTS: CGN patients had signs of affection of parietal effects of vascular endothelium. In particular, increased excretion of functionally active WF, PAI-I and FDP correlating with activity/severity of CGN. The changes were especially noticeable in patients with progressive forms of CGN (with NS and RF). Patients with morphologically verified TIF (interstitial area more than 20%) excretion of endothelial dysfunction markers was higher than in CGN patients free of TIF In a progressive course of nephritis endothelial dysfunction deteriorates by endothelial proliferation/regeneration impairment as shown by reduced urinary excretion of angiogenic factor VEGF and parallel elevation of functionally active WF in urine of patients with severe forms of CGN. Combined contribution of endothelial dysfunction and angiogenesis impairment to mechanisms of TIF development is seen from these values relations with severity of creatinemia and fibrous alterations in tubulointerstitial tissues of the kidney. CONCLUSION: The results point to participation of endothelium in mechanisms promoting development of TIF and RF in CGN both in terms of endothelial dysfunction and impairment of endothelial repair capacity. Clinicomorphological comparisons confirm the significance of WF, PAI-I and VEGF in assessment of local-renal endothelial changes and severity of fibrosis in renal tissue in CGN. Due to availability of the study material, perspectives of fibrogenesis monitoring in the kidneys with the tests appear which is essential for making prognosis and treatment policy in CGN patients.