人脑胶质瘤VEGF的表达和微血管检测及意义

目的探讨人脑胶质瘤中血管内皮细胞生长因子(VEGF)的表达与微血管数量(MVQ)和肿瘤良恶性程度的关系. 方法用免疫组织化学染色方法检测手术切除石蜡包埋的47例人脑胶质瘤(Ⅰ～Ⅱ级22例,Ⅲ级15例,Ⅳ级10 例)组织中的VEGF蛋白表达情况和MVQ数量,借助显微镜观察其阳性细胞数和阳性血管数; 另外,分别取脑外伤后开颅内减压术中切除的正常脑组织10例作为对照组. 结果①正常脑组织未检测到VEGF蛋白的表达,而MVQ数量少 ,表达强度弱;②各级别胶质瘤组织中均有VEGF和MVQ表达,主要表达于肿瘤细胞的胞浆和血管内皮细胞胞膜中;③3组胶质细胞瘤中VEGF的表达阳性率分别为22.2%、86.7%、90%、Ⅰ～Ⅱ级组与其它两组间差异有显著性意义(p<0.05;p<0.01),VEGF表达阳性组的MVQ平均值(46.8±12.4)明显高于阴性组MVQ值 (22.4±11.5)(p<0.01);④VEGF的表达与MVQ相关(r=0.75, p <0.001). 结论①VEGF在脑胶质瘤血管生成中起重要作用 ,能促进胶质瘤血管的形成;②VEGF和MVQ与胶质瘤良恶性程度明显相关,可作为脑胶质瘤病理诊断的补充指标;③VEGF可作为治疗脑胶质瘤的靶向,为胶质瘤的基因治疗提供指导方向.     

人脑胶质瘤血管内皮细胞生长因子受体表达的研究

目的研究人脑胶质瘤血管内皮细胞生长因子受体(Vascular endot helial growth factor receptors, VEGFR)的表达及意义.方法应用免疫组织化学技术,检测52例手术切除的脑胶质细胞瘤组织中两种VEGFR(flt-1和fl k-1)的表达.结果①胶质细胞瘤组织中有flt-1和flk-1的表达 , 主要表达于肿瘤血管内皮细胞, 同时巨噬细胞的胞浆中也有表达;② 3组胶质细胞瘤中,VEGFR的表达率分别为16.0%、58.8%、90.0%,3组间有差异(p<0.05 );③脑胶质细胞瘤中, flt-1的表达与flk-1 的表达相关(R=0.993,p<0.01).结论正常脑组织中无VEGFR表达,脑胶质细胞瘤中有VEGFR表达,主要表达于血管内皮细胞中,VEGF通过旁分泌途径刺激脑胶质细胞瘤的血管发生; VEGF的促血管发生作用既可通过血管内皮细胞的VEGFR直接产生,又可通过促进巨噬细胞的局灶浸润间接产生;VEGFR表达与脑胶质瘤恶性程度呈正相关.     

血管内皮细胞生长因子及其受体的分子生物学研究进展

血管内皮细胞生长因子(vascular endothelial cell growth factor,VEGF)是最直接的血管内皮细胞促分裂素,它通过其受体(VEGFR)介导其活性,不同VEGF剪接体与不同类型的VEGFR结合,通过胞内信号传导,发挥不同的生物学效应。本文总结了VEGF及其受体的结构、特点、分类、分子生物学特征、二者的连结及由VEGF诱导的胞内信号传导作用,并简单讨论了它们可能的应用前景。     

人脑胶质瘤VEGF的表达和微血管检测及意义

目的探讨人脑胶质瘤中血管内皮细胞生长因子(VEGF)的表达与微血管数量(MVQ)和肿瘤良恶性程度的关系. 方法用免疫组织化学染色方法检测手术切除石蜡包埋的47例人脑胶质瘤(Ⅰ～Ⅱ级22例,Ⅲ级15例,Ⅳ级10 例)组织中的VEGF蛋白表达情况和MVQ数量,借助显微镜观察其阳性细胞数和阳性血管数; 另外,分别取脑外伤后开颅内减压术中切除的正常脑组织10例作为对照组. 结果①正常脑组织未检测到VEGF蛋白的表达,而MVQ数量少 ,表达强度弱;②各级别胶质瘤组织中均有VEGF和MVQ表达,主要表达于肿瘤细胞的胞浆和血管内皮细胞胞膜中;③3组胶质细胞瘤中VEGF的表达阳性率分别为22.2%、86.7%、90%、Ⅰ～Ⅱ级组与其它两组间差异有显著性意义(p<0.05;p<0.01),VEGF表达阳性组的MVQ平均值(46.8±12.4)明显高于阴性组MVQ值 (22.4±11.5)(p<0.01);④VEGF的表达与MVQ相关(r=0.75, p <0.001). 结论①VEGF在脑胶质瘤血管生成中起重要作用 ,能促进胶质瘤血管的形成;②VEGF和MVQ与胶质瘤良恶性程度明显相关,可作为脑胶质瘤病理诊断的补充指标;③VEGF可作为治疗脑胶质瘤的靶向,为胶质瘤的基因治疗提供指导方向.     

脑胶质瘤表皮生长因子受体表达及其意义

脑胶质瘤表皮生长因子受体表达及其意义袁志忠叶挺军陈泳莲近十年来，国外的研究已证实，胶质瘤常有表皮生长因子受体（ｅｐｉｄｅｒｍａｌｇｒｏｗｔｈｆａｃｔｏｒｒｅｃｅｐｔｏｒ，ＥＧＦＲ）基因扩增、重排及蛋白产物的过度表达和结构异常，且与肿瘤的发生和发展有关...     

血管内皮生长因子受体在膀胱癌中的表达及临床意义

目的：探讨血管内皮生长因子受体在膀胱癌中的表达及与临床病理因素的相关性。方法：免疫组化法采用链霉菌抗生物素一过氧化物酶连接法(SP法)对50例膀胱癌标本，20例正常膀胱组织标本中血管内皮生长因子受体的表达进行检测。结果：血管内皮生长因子受体在大多数膀胱癌组织中表达(74％)，而且其表达水平与病理分期及组织分级呈正相关。在正常膀胱组织中无1例表达(0％)。结论：膀胱癌组织中血管内皮生长因子受体阳性表达，提示其在膀胱癌的血管生成中起着重要作用。     

血管内皮细胞生长因子受体KDR胞外配基结合区单抗对内皮细胞增殖及血管形成的抑制

目的　研制能封闭血管内皮生长因子 (VEGF)受体KDR的单克隆抗体 (McAb) ,探讨其抑制VEGF诱导的体内外活性。方法　以原核表达的KDRⅠ～Ⅳ区融合蛋白免疫BALB/c小鼠 ,用杂交瘤技术制备抗KDRⅠ～Ⅳ的McAb ,并用免疫双扩、ELISA和Western免疫印迹鉴定其亚类和抗原结合特异性 ,用VEGF刺激内皮细胞增殖及鸡胚血管形成实验检测该抗体的中和活性。结果　通过筛选和鉴定获得了 2株KDRⅠ～Ⅳ区McAbs(3G9、1E4) ,其分泌抗体亚类分别为IgG1和IgM。 2株McAb均能明显抑制VEGF诱导的内皮细胞 (EC)增殖 ,经纯化的McAb 3G9能明显抑制经VEGF刺激的鸡胚血管形成。结论　KDRⅠ～Ⅳ区McAb可能通过封闭内源性KDR而抑制VEGF活性 ,McAb 3G9具有潜在治疗肿瘤的应用前景。     

血管内皮细胞生长因子A与自身免疫性疾病

血管内皮细胞生长因子-A(vascular endothe-lial growth factor-A,VEGF-A)是70年代末期发现的一种肿瘤细胞分泌的具有多种功能的细胞因子,它是VEGF家族中最早的成员,是正常血管发生和血管形成所必需的.除了增加微血管的通透性外,VEGF-A还可刺激内皮细胞迁移分化,保护它们避免凋亡和衰老.     

可溶性血管内皮生长因子受体1真核克隆表达及其对血管内皮细胞增殖的影响

本研究旨在构建可溶性血管内皮生长因子(vascular endothelial growth factor,VEGF)受体1(soluble fmslike tyosine kinase-1,sFlt-1)的真核表达质粒pcDNA3.1-sFlt-1,并观察sFlt-1对血管内皮细胞增殖的影响。提取人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs)总RNA,扩增Flt-1基因胞外1-3结构域,构建真核表达质粒pcDNA3.1-sFlt-1,测序鉴定基因序列。将重组质粒转染Lewis肺癌细胞,采用RT-PCR和SDS-PAGE检测sFlt-1在基因及蛋白水平的表达情况。MTT法检测sFlt-1对VEGF诱导的HUVECs生长的影响。结果显示:①插入片段序列正确;②sFlt-1在基因水平成功表达且转染后的Lewis肺癌细胞能分泌表达sFlt-1;③含sFlt-1的细胞上清液可明显抑制VEGF诱导的HUVECs增殖。本研究成功构建了真核表达质粒pcDNA3.1-sFlt-1,sFlt-1,在基因和蛋白水平均获得有效表达,且表达的蛋白可明显抑制由VEGF诱导...     

血管内皮细胞生长因子受体结构与功能分析

血管内皮细胞生长因子受体(VEGFR)是VEGF特异性的受体,属于酪氨酸激酶亚家庭中的一个新成员,具有特征性的胞外区和酪氨酸激酶区,因其在刺激血管内皮细胞增殖、促进新生血管生成,特别是在促进肿瘤生长及转移中的作用,已越来越成为人们研究的热点。本文概括了3种VEGF受体在体内的不同分布,分析了不同VEGF受体在碱基序列及蛋白质功能结构域的异同,并介绍了可溶性VEGF受体功能差异,以及在肿瘤及与血管生成有关等疾病上的应用。     

Immunohistochemical Expression of Vascular Endothelial Growth Factor and Vascular Endothelial Growth Factor Receptor in Canine Cutaneous Fibrosarcomas

The expression of five markers associated with tumour angiogenesis, proliferation and apoptosis was studied in 24 canine cutaneous fibrosarcomas. Tumours were assigned histological grades and were immunohistochemically evaluated for the expression of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR-2). Additionally, intra-tumour microvessel density (iMVD) was assessed by immunohistochemical labelling for expression of von Willebrand factor (vWf) and tumour proliferation index (PI) was measured following labelling of Ki-67 antigen. Finally, tumour apoptotic index (AI) was determined by application of the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP end-labelling method (TUNEL). VEGF and VEGFR-2 expression were detected in 22/24 (92%) and 24/24 (100%) of fibrosarcomas, respectively. There was correlation between VEGF and VEGFR-2 expression (r = 0.51) and between histological grade and PI (r = 0.82). A significant difference in PI between tumours of different histological grade was found (P < 0.05). The median PI in grade 2 and 3 tumours (30.6 and 54.7, respectively) was significantly higher than in grade 1 tumours (6.4). Therefore, only PI correlates significantly with the histological grade of canine cutaneous fibrosarcomas. The potential for autocrine activity for VEGF exists in canine cutaneous fibrosarcomas, as VEGF and VEGFR-2 expression was found in most tumours.     

In Vitro Expression of Vascular Endothelial Growth Factor and Its Receptors by Placental Macrophages

The expression of VEGF and membrane-bound and soluble forms of the VEGF-R1 receptor in cultured placental macrophages (trimesters I and III of pregnancy) was studied by flow cytometry, cytometric bead array, and ELISA. Nearly all population of placental macrophages (98%) was capable of producing VEGF during the early and late gestational periods. However, the expression of cellular VEGF-R1 varied from 3.4 to 92%. VEGF secretion was relatively low in the first and third trimesters (0.5 and 1.1 pg/105 cells, respectively). Cultured placental macrophages produced soluble receptor sVEGF-R1 in the first and third trimesters (86.4 and 36.4 pg/105 cells, respectively). Stimulation with LPS was followed by a 4-fold increase in sVEGF-R1 secretion. Our results indicate that placental macrophages are involved in the autocrine and paracrine regulation in chorionic villi. The data suggest that these cells have a physiological and pathogenetic role in gestation.     

Resveratrol Inhibits Hypoxia-Induced Vascular Endothelial Growth Factor Expression and Pathological Neovascularization

Purpose

To investigate the effects of resveratrol on the expression of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in human adult retinal pigment epithelial (ARPE-19) cells, and on experimental choroidal neovascularization (CNV) in mice.

Materials and Methods

ARPE-19 cells were treated with different concentrations of resveratrol and then incubated under hypoxic conditions with subsequent evaluation of cell viability, expression of HIF-1α, and expression of VEGF. The effects of resveratrol on the synthesis and degradation of hypoxia-induced HIF-1α were evaluated using inhibitors of the PI3K/Akt/mTOR and the ubiquitin proteasome pathways. In animal studies, CNV lesions were induced in C57BL/6 mice by laser photocoagulation. After 7 days of oral administration of resveratrol or vehicle, which began one day after CNV induction, image analysis was used to measure CNV areas on choroidal flat mounts stained with isolectin IB4.

Results

In ARPE-19 cells, resveratrol significantly inhibited HIF-1α and VEGF in a dose-dependent manner, by blocking the PI3K/Akt/mTOR signaling pathway and by promoting proteasomal HIF-1α degradation. In mice experiments, orally administered resveratrol significantly inhibited CNV growth in a dose-dependent manner.

Conclusion

Resveratrol may have therapeutic value in the management of diseases involving pathological neovascularization.     

Vascular Endothelial Growth Factor (VEGF) Expression in Human Pituitary Adenomas and Carcinomas

Vascular endothelial growth factor (VEGF) is a key mediator of endothelial cell proliferation, angiogenesis, and vascular permeability. Little is known about its expression in human pituitary adenomas. We examined 148 human pituitary adenomas for VEGF protein expression by immunohistochemistry. The strongest immunoreactivity was present in GH adenomas, corticotroph, silent corticotroph, silent subtype 3, and nononcocytic null cell adenomas. GH adenomas treated with octreotide strained less intensely than did untreated tumors. Relatively weak staining was present in PRL, gonadotroph, thyrotroph, and oncocytic null cell adenomas in the same sections showed evidence of down-regulation of VEGF protein expression in adenomas. Pituitary carcinomas usually had stronger staining than adenomas. In situ hybridization studies with oligonucleotide probes showed positive staining in all groups with stronger staining in GH, ACTH, TSH, and gonadotroph adenomas and in pituitary carcinomas. These results indicate that VEGF expression is more prominent in certain adenoma subtypes, that decreased expression occurs in adenomas as compared to nontumorous pituitary and that carcinomas show increased VEGF expression relative to adenomas suggesting up-regulation of VEGF during pituitary tumor progression.     

Polarized Vascular Endothelial Growth Factor Secretion by Human Retinal Pigment Epithelium and Localization of Vascular Endothelial Growth Factor Receptors on the Inner Choriocapillaris : Evidence for a Trophic Paracrine Relation

The retinal pigment epithelium (RPE) maintains the choriocapillaris (CC) in the normal eye and is involved in the pathogenesis of choroidal neovascularization in age-related macular degeneration. Vascular endothelial growth factor-A (VEGF) is produced by differentiated human RPE cells in vitro and in vivo and may be involved in paracrine signaling between the RPE and the CC. We investigated whether there is a polarized secretion of VEGF by RPE cells in vitro. Also, the localization of VEGF receptors in the human retina was investigated. We observed that highly differentiated human RPE cells, cultured on transwell filters in normoxic conditions, produced two- to sevenfold more VEGF toward their basolateral side as compared to the apical side. In hypoxic conditions, VEGF-A secretion increased to the basal side only, resulting in a three- to 10-fold higher basolateral secretion. By immunohistochemistry in 30 human eyes and in two cynomolgus monkey eyes, KDR (VEGFR-2) and flt-4 (VEGFR-3) were preferentially localized at the side of the CC endothelium facing the RPE cell layer, whereas flt-1 (VEGFR-1) was found on the inner CC and on other choroidal vessels. Our results indicate that RPE secretes VEGF toward its basal side where its receptor KDR is located on the adjacent CC endothelium, suggesting a role of VEGF in a paracrine relation, possibly in cooperation with flt-4 and its ligand. This can explain the known trophic function of the RPE in the maintenance of the CC and its fenestrated permeable phenotype and points to a role for VEGF in normal eye functioning. Up-regulated basolateral VEGF secretion by RPE in hypoxia or loss of polarity of VEGF production may play a role in the pathogenesis of choroidal neovascularization.     

循证血管发生因子PD-ECGF、VEGF及抑制因子TSP-1在子宫内膜异位症发病因素中的作用

目的 :循证血小板衍化内皮细胞生长因子PD ECGF、血管内皮细胞生长因子VEGF、血小板反应素TSP 1在子宫内膜异位症 (EM )发病因素中的作用。方法 :3 0例需行手术治疗的EM患者 ,取其在位和异位内膜作免疫组化SP法检测PD ECGF、VEGF ,原位杂交法检测TSP 1的表达 ,以 3 0例非EM患者的子宫内膜作为对照 ,进行比较分析。结果 :异位内膜PD ECGF表达升高 ,EM患者子宫内膜TSP 1表达较对照组降低。结论 :PD ECGF参与了EM血管发生 ,EM患者子宫内膜抑制血管发生能力降低 ,使异位的内膜易于种植生长可能是EM发病的因素之一