小鼠视网膜血管内皮细胞生长因子与视网膜新生血管的相关性研究

目的研究氧诱导视网膜新生血管小鼠模型中视网膜血管内皮细胞生长因子(VEGF)与视网膜新生血管的相关性。方法通过建立氧诱导视网膜新生血管小鼠模型,分别于12、14、17、21 d龄随机抽取2组幼鼠各6只,一侧眼球测定视网膜VEGF水平,另一侧眼球进行视网膜铺片、ADP酶染色,考察其相关性。结果模型组小鼠左眼球ADP酶染色结果显示,模型组12 d龄小鼠血管迂曲、扩张、变形,随时间延长血管变形加重,17 d时最严重,且视乳头周围出现大片无灌注区,视网膜周边可见大量新生血管生成,到21 d时模型开始恢复。视网膜VEGF测定结果显示,12 d龄模型小鼠VEGF开始升高,17 d达峰值,以后下降。结论视网膜VEGF变化和视网膜血管形态具有很好的正相关性,17 d时新生血管形成最多。     

Antiangiogenic agents targeting vascular endothelial growth factor and its receptors in clinical development

There is ample therapeutic opportunity for the use of antiangiogenic inhibitors in the clinic, as there are several human diseases that are dependent upon angiogenesis [1]. However, no disease has attracted as much attention as a target for antiangiogenic therapy as malignant disorders. There is a vast amount of literature acting as proof-of-principle for the use of angiogenic inhibitors as effective agents for blocking tumour-induced angiogenesis and subverting tumour growth and disease dissemination. One of the unique attractions of targeting tumour angiogenesis is that vascular endothelial cells are a genetically stable population in which acquisition of therapeutic resistance might be less efficient than in genetically unstable tumour cells [2,3]. This review covers inhibitors that target the tumour angiogenic agent vascular endothelial growth factor and its receptors as one such antiangiogenic approach. Many agents in this class are in clinical trials with limited reports of toxicity and some early evidence of clinical benefit.     

Antiangiogenic agents targeting vascular endothelial growth factor and its receptors in clinical development

There is ample therapeutic opportunity for the use of antiangiogenic inhibitors in the clinic, as there are several human diseases that are dependent upon angiogenesis [1]. However, no disease has attracted as much attention as a target for antiangiogenic therapy as malignant disorders. There is a vast amount of literature acting as proof-of-principle for the use of angiogenic inhibitors as effective agents for blocking tumour-induced angiogenesis and subverting tumour growth and disease dissemination. One of the unique attractions of targeting tumour angiogenesis is that vascular endothelial cells are a genetically stable population in which acquisition of therapeutic resistance might be less efficient than in genetically unstable tumour cells [2,3]. This review covers inhibitors that target the tumour angiogenic agent vascular endothelial growth factor and its receptors as one such antiangiogenic approach. Many agents in this class are in clinical trials with limited reports of toxicity and some early evidence of clinical benefit.     

血管内皮生长因子165诱导人血管内皮细胞多药耐药表型

目的：研究血管内皮生长因子165（VEGF165）对血管内皮细胞药物敏感性的影响。方法：人真皮微血管内皮细胞（HDMEC）与抗癌药物和VEGF165混合培养,MTT法分析药敏变化,琼脂糖电泳检测细胞凋亡,RT-PCR、免疫印迹法分析HDMEC产生多药耐药表型的机制。结果：VEGF165体外诱导HDMEC对多种抗癌药物耐药,如表柔比星、顺铂、足叶乙甙、丝裂霉素C、长春新碱、CPT-11、泰素等,其机制与VEGF165诱导HDMEC上调表达多药耐药相关蛋白和肺耐药相关蛋以及下调表达Bax蛋白有关。结论：VEGF165诱导血管内皮细胞的多药耐药表型,提示化疗时抗癌药物的抗血管生成活性可能取决于肿瘤微环境。     

黄樟素氧化物对去除成纤维细胞生长因子所诱导的血管内皮细胞凋亡及生长的影响

目的:研究黄樟素氧化物对去除成纤维细胞生长因子(FGF)诱导的血管内皮细胞凋亡及生长的影响.方法:光学显微镜观察细胞形态学变化;MTT法测定细胞生长;DNA电泳和荧光显微技术检测DNA断裂;流式细胞术测定细胞周期分布.结果:黄樟素氧化物5-25mg/L处理去除FGF的血管内皮细胞24h,细胞铺展和生长被促进,细胞脱壁和DNA片段化被抑制,黄樟素氧化物10mg/L对细胞周期分布无明显影响.黄樟素氧化物50-100 mg/L促进血管内皮细胞的脱壁和DNA片段化,黄樟素氧化物100mg/L将细胞周期阻断于G_2-M期.结论:黄樟素氧化物在10mg/L时抑制血管内皮细胞凋亡,而在100mg/L时促进其凋亡,该药物对血管内皮细胞生长和凋亡有重要影响.     

Weight loss induced by tyrosine kinase inhibitors of the vascular endothelial growth factor pathway

Weight loss, cachexia and sarcopenia are profound problems in the frail oncologic patients. With the development and increasing use of angiogenesis inhibitors in metastatic cancer patients, the question arises as to their influence on body weight and composition. Angiogenesis is not only important for the growth, development and metastatic potential of tumors but also for physiological processes in adipogenesis. A less known approach of angiogenesis inhibitors is their experimental use in obese models. This review focuses on the effects on the body weight and composition of angiogenesis inhibitors, especially of those targeting the vascular endothelial growth factor pathway.     

氟伐他汀对高糖诱导人足细胞血管内皮生长因子表达的影响及机制

目的探讨氟伐他汀对高糖诱导的人足细胞血管内皮生长因子(VEGF)表达的影响及机制。方法体外培养人足细胞,随机分为A组(正常糖组)、B组(高糖组)、C组(高糖+氟伐他汀10-7mol/L组)、D组(高糖+氟伐他汀10-6mol/L组)、E组(高糖+氟伐他汀10-5mol/L组)和F组[高糖+胞外信号调节激酶(ERK)抑制剂PD98059组]。用Western blot检测VEGF和磷酸化ERK1/2(pERK1/2)蛋白表达。结果 B组VEGF、pERK1/2表达较A组明显升高,并呈时间依赖性(P<0.05)。F组VEGF、pERK1/2表达较B组显著降低(P<0.01)。与B组比较,C、D、E组VEGF及pERK1/2表达亦明显减少,并呈浓度依赖性(P<0.05)。结论高糖刺激体外培养人足细胞VEGF表达增加,氟伐他汀可减少高糖诱导的VEGF表达,其机制可能与氟伐他汀抑制ERK信号通路有关。     

Vascular targeting of ocular neovascularization with a vascular endothelial growth factor121/gelonin chimeric protein

Tumors provide an extremely abnormal microenvironment that stimulates neovascularization from surrounding vessels and causes altered gene expression within vascular cells. Up-regulation of vascular endothelial growth factor (VEGF) receptors has allowed selective destruction of tumor vessels by administration of a chimeric protein consisting of VEGF121 coupled to the toxin gelonin (VEGF/rGel). We sought to determine whether there is sufficient up-regulation of VEGF receptors in endothelial cells participating in ocular neovascularization to permit a similar strategy. After intravenous injection of 45 mg/kg VEGF/rGel, but not uncoupled recombinant gelonin (rGel), there was immunofluorescent staining for rGel within choroidal neovascularization in mice and regression of the neovascularization occurred, demonstrating successful vascular targeting via the systemic circulation. Intraocular injection of 5 ng of VEGF/rGel also caused significant regression of choroidal neovascularization and regression of retinal neovascularization in two models, transgenic mice with expression of VEGF in photoreceptors and mice with ischemic retinopathy, whereas injection of 5 ng of rGel had no effect. These data suggest that the strategy of vascular targeting can be applied to nonmalignant neovascular diseases and could serve as the basis of a new treatment to reduce established ocular neovascularization.     

Captopril attenuates hypertension and renal injury induced by the vascular endothelial growth factor inhibitor sorafenib

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诺帝对血管内皮生长因子诱导的人脐血源性内皮祖细胞功能的影响

探讨手性化合物诺帝(Nordy)对血管内皮生长因子(VEGF)诱导的人脐血源性内皮祖细胞(EPCs)功能的影响及其意义。应用密度梯度离心法分离新鲜人脐血的单个核细胞，接种于EGM-2培养液中培养7～10 d获得内皮祖细胞(EPCs)。分别采用MTT法、Millicell-PCF培养小室系统和Matrigel内小管形成试验检测诺帝对VEGF刺激下EPCs增殖活性、迁移能力和体外形成小管样结构能力的影响。结果表明，100 μmol·L^-1诺帝作用24 h明显抑制EPCs增殖活性(P<0.05)，诺帝(25～50 μmol·L^-1)作用48～72 h也明显抑制EPCs增殖活性(P<0.05)。诺帝(25～100 μmol·L^-1)显著抑制VEGF诱导的EPCs迁移活性和体外形成小管样结构的能力(P<0.05)。诺帝能抑制体外VEGF诱导的人脐血源性EPCs增殖、迁移和体外小管形成能力，提示其具有抗EPCs效应。     

Effect of an oversulfated exopolysaccharide on angiogenesis induced by fibroblast growth factor-2 or vascular endothelial growth factor in vitro

The aim of this study was to determine the angiogenic properties of an oversulfated exopolysaccharide (OS-EPS) derived from a polysaccharide secreted by the mesophilic bacterium Alteromonas infernus. We compared the effect of this OS-EPS with that of a non-oversulfated exopolysaccharide (EPS) on human umbilical vein endothelial cell (HUVEC) proliferation, migration and differentiation induced by basic fibroblast growth factor (FGF-2) or vascular endothelial growth factor (VEGF). OS-EPS enhanced HUVEC proliferation by 58% when used alone, and by respectively 30% and 70% in the presence of FGF-2 and VEGF. OS-EPS also increased the density of tubular structures on Matrigel in the presence of FGF-2 or VEGF. Vascular tube formation was related to alpha(6) integrin subunit expression, which was enhanced by 50% in the presence of the growth factors. Indeed, a monoclonal anti-alpha(6) blocking antibody abolished this vascular tube formation. EPS had no effect in any of the experimental conditions, underlying the importance of sulfation in the angiogenic effects of exopolysaccharide. By potentiating the angiogenic activity of FGF-2 and/or VEGF, OS-EPS, which possesses low anticoagulant activity and thus a low hemorrhagic risk, could potentially be used to accelerate vascular wound healing or to promote the growth of collateral blood vessels in ischemic tissues.     

血管内皮生长因子对顺铂所致豚鼠耳蜗损伤的拮抗作用

目的应用微渗透压泵将血管内皮生长因子(VEGF)导入豚鼠耳蜗,观察VEGF对顺铂所致耳蜗毒性的拮抗作用。方法豚鼠ip顺铂造成耳蜗损伤。将VEGF以微渗透压泵导入实验组豚鼠右耳蜗,对照组导入等量磷酸缓冲液。用扫描电镜观察两组豚鼠右耳蜗毛细胞的损伤,同时检测并比较两组豚鼠右耳在实验前、后听觉脑干诱发电位(ABR)听阈的改变。结果对照组豚鼠右耳毛细胞的损伤明显重于实验组,且其ABR听阈显著高于实验组。结论微渗透压泵耳蜗灌注VEGF对顺铂所致的活体耳蜗损伤有明显的拮抗作用。     

Effect of vascular endothelial growth factor and epidermal growth factor on iatrogenic apoptosis in human endothelial cells

To study the effect of growth factors on iatrogenic apoptosis, we examined the influence of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) on staurosporine-induced apoptosis in primary cultures of human umbilical vein endothelial cells (HUVEC). Apoptosis was evaluated by a cell viability test, the TUNEL-POD assay and the activation of the pro-apoptotic caspase-3. Staurosporine (10-100nM) caused the activation of caspase-3. This effect was manifest after 2hr of incubation and reached its maximum after 5hr. Severe loss of viability followed within 18hr. VEGF or EGF (10-100ng/mL) added together with staurosporine decreased the activation of caspase-3. The loss of viability was 24hr delayed. The action of growth factors was observed at 1% serum concentration but also at concentration optimal for HUVEC survival (10%, v/v). Furthermore, the inhibition of PI-3 kinase (PI-3K) by wortmannin or LY294002 as well as the inhibition of MEK by PD098059 or U0126 prevented the protective effect of VEGF and EGF. Western blotting analysis showed that after 3hr of incubation with staurosporine the level of the anti-apoptotic protein Mcl-1 decreased and this effect was reverted by VEGF. It is concluded that VEGF and EGF antagonize the pro-apoptotic action of staurosporine by the combined signalling of PI-3K and ERKs pathways.     

Vasorelaxation induced by vascular endothelial growth factor in the human internal mammary artery and radial artery

OBJECTIVES: Due to potential therapeutic value of vascular endothelial growth factor (VEGF) in coronary artery disease, the effect and mechanism of VEGF in human arteries used as coronary bypass grafts become important but not fully understood. VEGF-mediated endothelial regulation in vasorelaxation was studied in internal mammary artery (IMA) and radial artery (RA), compared with that of the classical agent-acetylcholine (ACh). The role of nitric oxide (NO), prostacyclin (PGI2), and endothelium-derived hyperpolarizing factor (EDHF) was investigated. METHODS: VEGF- and ACh-induced responses were measured in RA and IMA with or without endothelium and in the absence or presence of inhibitors of nitric oxide synthase or prostacyclin. In addition, the VEGF-induced PGI2 was measured by enzyme immunoassay. RESULTS: VEGF induced similar relaxation in RA (59.2+/-9.3%) and IMA (56.1+/-6.4%) that was significantly inhibited by N(omega)-nitro-L-arginine (L-NNA) plus oxyhemoglobin (HbO) (IMA: 24.9+/-4.3%, P=0.03 vs. RA: 25.0+/-8.6%, P=0.01) or by indomethacin (INDO) (IMA: 21.8+/-2.5%, P=0.000 vs. RA: 30.0+/-6.6%, P=0.04) with more inhibition in IMA than RA (P<0.05). In addition, the VEGF-induced PGI2 was significantly higher in IMA than RA (11.5+/-2.1 vs. 4.9+/-1.1 pg/ml/mg, P=0.002). INDO+L-NNA+HbO reduced the VEGF-induced relaxation to 20.8+/-4.6% in RA vs. 4.8+/-1.6% in IMA (P=0.01). In contrast, the maximal relaxation induced by ACh in RA (55.9+/-6.0%) and IMA (48.5+/-5.3%) was largely inhibited by L-NNA in IMA and RA (14.7+/-3.0%, P=0.000 vs. 15.2+/-3.2%, P=0.004) but little affected by INDO. CONCLUSIONS: VEGF induces similar relaxation in IMA and RA with significantly more PGI2-mediated relaxation and higher stimulated PGI2 level in IMA but more EDHF-mediated relaxation in RA. In comparison, ACh-induced relaxation mainly depends on NO. Thus, our study reveals a significant difference in the mechanism of the endothelium-dependent relaxation induced by VEGF and ACh.     

Therapies directed at vascular endothelial growth factor

The inhibition of angiogenesis through vascular endothelial growth factor (VEGF) receptor targeting is a strategy that is relatively tumour selective. The high selectivity achieved with neutralising antibodies, soluble receptors and ribozymes reduces the risk of adverse reactions not related to VEGF inhibition itself. Small-molecule, orally-active protein kinase inhibitors provide an attractive alternative for chronic therapy, although specifically targeting a small subset of protein kinases from the ~ 550 expressed in mammalian cells is a challenge. Current efforts have resulted in promising clinical data for several synthetic VEGF receptor kinase inhibitors, of which PTK787/ZK222584 and ZD6474 are proceeding into large size clinical trials. It seems likely that blockers of the VEGF signalling pathway will be unsuitable for monotherapy, and that their role will be as an adjunct to additional antiangiogenic agents together with directly-acting antitumour agents or radiation therapy. Caution is needed with combinations of antiVEGF therapies and cytotoxic agents, as coadministration of cytotoxic agents with either the kinase inhibitor SU5416 or the VEGF antibody avastin appears to be associated with bleeding and thrombotic adverse events.     

Therapies directed at vascular endothelial growth factor

The inhibition of angiogenesis through vascular endothelial growth factor (VEGF) receptor targeting is a strategy that is relatively tumour selective. The high selectivity achieved with neutralising antibodies, soluble receptors and ribozymes reduces the risk of adverse reactions not related to VEGF inhibition itself. Small-molecule, orally-active protein kinase inhibitors provide an attractive alternative for chronic therapy, although specifically targeting a small subset of protein kinases from the approximately 550 expressed in mammalian cells is a challenge. Current efforts have resulted in promising clinical data for several synthetic VEGF receptor kinase inhibitors, of which PTK787/ZK222584 and ZD6474 are proceeding into large size clinical trials. It seems likely that blockers of the VEGF signalling pathway will be unsuitable for monotherapy, and that their role will be as an adjunct to additional antiangiogenic agents together with directly-acting antitumour agents or radiation therapy. Caution is needed with combinations of anti-VEGF therapies and cytotoxic agents, as coadministration of cytotoxic agents with either the kinase inhibitor SU5416 or the VEGF antibody avastin appears to be associated with bleeding and thrombotic adverse events.