Roundabout 4在肿瘤血管新生及细胞迁移中作用的研究进展

视网膜新生血管性疾病是世界范围内最严重的致盲性眼病之一,包括糖尿病视网膜病变、年龄相关性黄斑变性等.近年来普遍认为血管生长因子是调控视网膜内皮细胞增生和新生血管形成的最主要因素.Roundabout 4( Robo4)是近年发现的一种跨膜蛋白,特异性表达于血管生成活跃的内皮细胞表面.目前的研究认为,Robo4能够调控内...     

血小板源性生长因子及血管周细胞与新生血管性眼病

血小板源性生长因子及其受体通过对血管周细胞增殖和迁移的调控参与了血管的新生和成熟过程.该通路调控的周细胞改变与糖尿病视网膜病变、早产儿视网膜病变和脉络膜新生血管性疾病密切相关.本文回顾了血小板源性生长因子及其受体的结构和功能、其对周细胞的调控作用、以及在相关眼病发生和发展中的作用机制等,并探讨了通过该通路发挥作用的药物在抗新生血管眼病治疗中的应用前景.     

血小板源性生长因子及血管周细胞与新生血管性眼病

血小板源性生长因子及其受体通过对血管周细胞增殖和迁移的调控参与了血管的新生和成熟过程.该通路调控的周细胞改变与糖尿病视网膜病变、早产儿视网膜病变和脉络膜新生血管性疾病密切相关.本文回顾了血小板源性生长因子及其受体的结构和功能、其对周细胞的调控作用、以及在相关眼病发生和发展中的作用机制等,并探讨了通过该通路发挥作用的药物在抗新生血管眼病治疗中的应用前景.     

血管内皮生长因子与视网膜新生血管性疾病

血管内皮生长因子（ＶＥＧＦ）是新近确定的一种特异性刺激血管内皮细胞增殖及新生血管形成的生长因子。视网膜血管内皮细胞存在ＶＥＧＦ高亲和受体，而且受体数目较其它组织内皮细胞多。ＶＥＧＦ的特点是它的表达受局部氧浓度的调节。视网膜血管内皮细胞、色素上皮细胞、周皮细胞、Ｍüｌｅｒ细胞均能合成并分泌ＶＥＧＦ，缺氧可上调其基因表达。ＶＥＧＦ既可刺激视网膜血管内皮细胞增殖及移行，也可诱导视网膜新生血管形成。视网膜新生血管性疾病患者玻璃体ＶＥＧＦ含量增高。组织学定位表明ＶＥＧＦ的表达主要在内核层、神经节细胞层、ＲＰＥ细胞及Ｍüｌｅｒ细胞。阻断ＶＥＧＦ的产生及生物活性，有助于治疗视网膜新生血管性疾病     

血管内皮生长因子与视网膜缺血性病变

视网膜中央静脉阻塞和增殖性糖尿病视网膜缺血性病变等常伴有眼内新生血管的形成。近年的研究表明，血管内皮生长因子（ＶＥＧＦ）是一种特异性内皮细胞有丝分裂原，可刺激内皮细胞增殖。视网膜缺氧产生的ＶＥＧＦｍＲＮＡ表达升高，在新生血管的形成过程中发挥重要作用。本文主要对ＶＥＧＦ的作用，以及ＶＥＧＦ与眼内新生血管形成之间的关系加以综述     

血管内皮生长因子与眼内新生血管

眼内新生血管是多种致盲眼病的病理生理基础,新生血管形成受多种因子调控,其中血管内皮生长因子(VEGF)是最重要的细胞因子。它与特异性受体结合后通过复杂机制促进血管内皮细胞增殖、迁移和通透性增加。缺氧可诱导VEGF表达,VEGF通过NO的介导作用发挥促血管新生的作用。还有多种抑制和促进血管因子共同作用于血管内皮细胞。目前,人们通过基因手段抑制VEGF及其受体达到抑制血管新生的作用,为眼内新生血管性疾病开辟前景。     

基质细胞衍生因子-1与视网膜新生血管

视网膜新生血管是主要的致盲因素之一,目前发生机制尚不明确。基质细胞衍生因子-1（SDF-1）是新近发现的趋化因子,与趋化因子受体4（CXCR4）共同构成SDF-1/CXCR4轴。SDF-1/CXCR4参与了炎症反应、造血干细胞归巢及肿瘤侵袭。研究表明,SDF-1还能通过促进血管内皮细胞的迁移增生,招募内皮祖细胞,调节促血管生成因子等途径诱导新生血管生成,在视网膜新生血管的发生发展中发挥重要作用。就SDF-1/CXCR4的生物学功能、对促视网膜新生血管形成的机制及其在视网膜新生血管性疾病防治中的应用前景进行综述。     

血管内皮生长因子与视网膜缺血性病变

视网膜中央静脉阻塞和增殖性糖尿病视网膜缺血性病变等常伴有眼内新生血管的形成。近年的研究表明，血管内皮生长因子（ＶＥＧＦ）是一种特异性内皮细胞有丝分裂原，可刺激内皮细胞增殖。视网膜缺氧产生的ＶＥＧＦ ｍＲＮＡ表达升高，在新生血管的形成过程中发挥重要作用。本文主要对ＶＥＧＦ的作用，以及ＶＥＧＦ与眼内新生血管形成之间的关系加以综述。     

富含半胱氨酸蛋白61的研究进展及其在眼科的应用

CCN家族属于基质细胞蛋白,富含半胱氨酸蛋白61(CYR61)是其中第一个被克隆的基因.CYR61蛋白参与调节细胞的增生、黏附、迁移、分化、凋亡以及细胞外基质的生成.CYR61与某些细胞因子和生长因子相互作用并调节其生物活性,包括转化生长因子-β(TGF-β)、肿瘤坏死因子-α(TN F-α)、血管内皮生长因子(VEGF)、骨形成蛋白(BMPs)以及Wnt家族成员等.CYR61是血管生成及骨和软骨生成的重要调控因子,在胚胎发育、创伤修复、肿瘤的发生和发展以及其他多种疾病的发病中起着重要的作用.研究发现,CYR61在体外可促进视网膜毛细血管内皮细胞的增生、迁移及生成管状结构,糖尿病大鼠视网膜及增生型糖尿病视网膜病变(PDR)患者玻璃体内CYR61均明显增高,且与VEGF有一定的关系,CYR61很可能参与视网膜新生血管性疾病,特别是糖尿病视网膜病变(DR)的发生和发展,对CYR61在DR中的作用及通路的研究为该病的发病机制及治疗提供了新的思路.就近年来CYR61的研究进展进行综述.     

血管生成素及其受体Tie-2与新生血管性眼病

血管生成素是近年来发现的特异性作用于血管内皮细胞的细胞因子,参与新生血管的形成和调控,其受体Tie-2属于酪氨酸激酶家族。本文就血管生成素及其受体Tie-2在眼部新生血管性疾病如糖尿病视网膜病变、年龄相关性黄斑变性及早产儿视网膜病变等的研究进展进行阐述。     

Potential anti-angiogenic role of Slit2 in corneal neovascularization

Slits are large secreted proteins critical for axon guidance and neuronal precursor cell migration in nervous system. Evidence suggests that classical neuronal guidance cues also regulate vascular development. Our objective was to investigate whether neuronal guidance cue Slit2 and Roundabout (Robo) receptors are involved in corneal neovascularization (NV). Corneal NV model in rats was induced by implantation of agarose-coated gelfoam pellets containing basic fibroblast growth factor (bFGF) into corneal stroma. Differential expression of Slit2 and Robo1-4 between normal and neovascularized cornea was detected by real-time RT-PCR and visualized by immunohistochemistry and in situ hybridization. Primary human umbilical vein endothelial cells (HUVECs) were harvested and their expression of Robo1–4 was detected by RT-PCR. Recombinant human Slit2 protein was prepared and the effect of it on the migration of vascular endothelial cells was examined using cell migration assay. Agarose-coated gelfoam pellets were able to induce well-localized and reproducible corneal NV model. A significant down-regulation of Slit2 and a strong up-regulation of Robo1 and Robo4 were seen in neovascularized cornea when compared with normal cornea (P < 0.05). Slit2, Robo1 and Robo4 were throughout the epithelium in normal cornea and markedly weak or absent in epithelium in neovascularized cornea, with Robo1 and Robo4 being prominent in vascular endothelial cells invading the stroma. Primary HUVECs were confirmed to express both Robo1 and Robo4 receptors and their migration was inhibited by Slit2 (P < 0.05). This is the first study to assess the association between Slit2 and corneal NV. Our findings suggest that the interaction of Slit2 with Robo1 and Robo4 receptors plays an essential role in inhibiting pathological neovascular processes of the cornea and may represent a new therapeutic target for corneal NV.     

Efficacy of intravitreal captopril on oxygen-induced retinopathy in mice

AIM: To study the inhibitory effect of intravitreal captopril on oxygen-induced retinopathy (OIR) in mice. METHODS: Eighty postnatal day (P)7 C57BL/6J mice were randomly divided into treated group and control group with forty mice in each group. The mice were exposed to 75% ± 2% oxygen for 5 days (P7-P11) and then returned to room air for 5 days (P12-P17) to induce retinal neovascularization (RNV). Beginning on P12, the mice in treated group received daily intravitreal injections of captopril (3.0mL/kg), while those in control group received daily intravitreal injections of phosphate-buffered saline (PBS) (3.0mL/kg) through P17. After anesthetized at P17, one eye was chosen randomly as experimental eye and were enucleated. RNV was examined by Adenosine diphosphate-ase (ADPase) stained retina flat-mounts and was quantitated histologically by counting the neovascular endothelial cell nuclei anterior to inner limiting membrane (ILM). The expressions of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) were measured by immunohistochemical method. RESULTS: Comparing with control group, more regular distributions, better branch and reduced density of RNV were observed in eyes of treated group. The number of neovascular cell nuclei was less in treated group than that in control group (t=6.135, P<0.01). Stain of MMP-2 and VEGF was weaker in treated group than that in control group. CONCLUSION: The results indicate that captopril can significantly inhibit RNV in OIR mice.     

Herbimycin A inhibits angiogenic activity in endothelial cells and reduces neovascularization in a rat model of retinopathy of prematurity

The pathogenesis of retinopathy of prematurity involves dysregulated angiogenesis resulting in pre-retinal growth of new vessels. Inhibition of tyrosine kinase-dependent pro-angiogenic signals may provide a rational therapeutic approach to the reduction of pre-retinal neovascularization. Vascular endothelial growth factor stimulates endothelial cell mitogenesis, differentiation and migration, by binding and activating the receptor tyrosine kinases vascular endothelial growth factor receptor-1 and vascular endothelial growth factor receptor-2. One of the vascular endothelial growth factor receptor substrates implicated in vascular endothelial growth factor signal transduction is c-Src. The ability of herbimycin A, a c-Src-selective tyrosine kinase inhibitor, to inhibit vascular endothelial growth factor-induced bovine retinal microvascular endothelial cell proliferation and tube formation was investigated. The ability of the compound to inhibit pathologic angiogenesis was tested in a rat model of retinopathy of prematurity. Exposure of neonatal rats to oxygen concentrations cycling between 10 and 50% induced severe pre-retinal neovascularization in all rats. Some of the eyes of these variable oxygen-exposed rats were herbimycin A-injected or vehicle-injected 1 or 3 days post-oxygen exposure while some eyes were non-injected. All rats were sacrificed for assessment 6 days post-exposure. Herbimycin A inhibited both vascular endothelial growth factor-induced bovine retinal microvascular endothelial cell proliferation and capillary tube formation in a dose-dependent manner. Injection of herbimycin A into oxygen-treated rats 1 day post-oxygen exposure produced a 63% decrease in pre-retinal neovascularization relative to vehicle (P = 0.0029). There was a 41% decrease in pre-retinal neovascularization in herbimycin-injected eyes relative to vehicle-injected eyes 3 days post-oxygen (P = 0.031). Pre-retinal neovascularization was reduced in vehicle-injected eyes relative to non-injected eyes at both injection times. There were no significant differences in retinal vascular area between any of the experimental groups. Based on the results of this study, herbimycin A inhibits endothelial cell proliferation and tube formation at non-toxic concentrations and reduces pre-retinal neovascularization in a rat model of retinopathy of prematurity. Reduction of angiogenesis by the inhibition of tyrosine kinase activity may be a viable route to the development of effective chemotherapies applicable to eye disease.     

Robo1/Robo4: Different expression patterns in retinal development

Two members of the roundabout (Robo) family, Robo1 and Robo4, serve as neuronal guidance receptors. During neurogenesis, Robo1 and Robo4 participate in axonal guidance by mediating a repulsive signal. It has been reported that Robo4 is mainly expressed in the vasculature and that Robo1 is expressed both in neural and non-neural tissues. However, the roles of these Robo proteins in the mammalian vasculature are still unclear. In this current study, the expression patterns of Robo1 and Robo4 in the retinal vasculature were determined using C57BL/6J mice at postnatal days (P) 1, P3, P5, P7, P9, P12, P14, P17, P21 and adult mice (1 month). We found that Robo4 was expressed not only in the retinal vessels but also in the retinal ganglion cell and photoreceptor layers during retinal development. Robo4 expression peaked at P3 and P9, which suggest that Robo4 may function in stabilizing the retinal vasculature. Robo1 expression was observed in the retina neuronal cells and vessels. Both Robo1 mRNA and protein expression showed a typical expression pattern, which related to Robo1’s roles in the different stages of retinal vascular development in the murine retina. Robo1 displayed high expression levels at P1 (correlated with superficial vascular plexus formation) and P7 (correlated with deep vascular plexus formation). The high levels of Robo1 during these two well-defined phases of retinal capillary plexus formation indicate that Robo1 is likely to play a part in retinal neovascularization.     

Pigment epithelium-derived factor suppresses ischemia-induced retinal neovascularization and VEGF-induced migration and growth

PURPOSE: To determine the effect of pigment epithelium-derived factor (PEDF) in a mouse model of ischemia-induced retinal neovascularization and on vascular endothelial growth factor (VEGF)--induced migration and growth of cultured microvascular endothelial cells. METHODS: Human recombinant PEDF was expressed in the human embryonic kidney 293 cell line and purified by ammonium sulfate precipitation and cation exchange chromatography. C57BL/6 mice were exposed to 75% oxygen from postnatal day (P)7 to P12 and then returned to room air. Mice received intravitreal injections of 2 microg PEDF in one eye and vehicle in the contralateral eye on P12 and P14. At P17, mice were killed and eyes enucleated for quantitation of retinal neovascularization. The mitogenic and motogeneic effects of VEGF on cultured bovine retinal and adrenal capillary endothelial cells were examined in the presence or absence of PEDF, using cell counts and migration assays. RESULTS: Two species of human recombinant PEDF, denoted A and B, were purified to apparent homogeneity. PEDF B appeared to comigrate on SDS-PAGE with PEDF from human vitreous samples. Changes in electrophoretic mobility after peptide-N-glycosidase F (PNGase F) digestion suggest that both PEDF forms contain N-linked carbohydrate. Analyses of the intact proteins by liquid chromatography-electrospray mass spectrometry (LC-ESMS) revealed the major molecular weight species for PEDF A (47,705 +/- 4) and B (46,757 +/- 5). LC-ESMS analysis of tryptic peptides indicated that PEDF A and B exhibit differences in glycopeptides containing N-acetylneuraminic acid (NeuAc) and N-acetylhexosamine (HexNAc). Intravitreal administration of either species of PEDF significantly inhibited retinal neovascularization (83% for PEDF A and 55% for PEDF B; P = 0.024 and 0.0026, respectively). PEDF A and B (20 nM) suppressed VEGF-induced retinal microvascular endothelial cell proliferation by 48.8% and 41.4%, respectively, after 5 days (P < 0.001) and VEGF-induced migration by 86.5% +/- 16.7% and 78.1% +/- 22.3%, respectively, after 4 hours (P = 0.004 and P = 0.008, respectively). CONCLUSIONS: These data indicate that elevated concentrations of PEDF inhibit VEGF-induced retinal endothelial cell growth and migration and retinal neovascularization. These findings suggest that localized administration of PEDF may be an effective approach for the treatment of ischemia-induced retinal neovascular disorders.     

Characterization and validation of a chronic retinal neovascularization rabbit model by evaluating the efficacy of anti-angiogenic and anti-inflammatory drugs

AIM:To establish a rabbit model with chronic condition of retinal neovascularization(RNV)induced by intravitreal(IVT)injection of DL-2-aminoadipic acid(DL-AAA),a retinal glial(Mül er)cell toxin,extensive characterization of DL-AAA induced angiographic features and the suitability of the model to evaluate anti-angiogenic and anti-inflammatory therapies for ocular vascular diseases.METHODS:DL-AAA(80 mmol/L)was administered IVT into both eyes of Dutch Belted rabbit.Post DL-AAA delivery,clinical ophthalmic examinations were performed weekly following modified Mc Donald-Shadduck Scoring System.Color fundus photography,fluorescein angiography(FA),and optical coherence tomography(OCT)procedures were performed every 2 or 4 wk until stable retinal vascular leakage was observed.Once stable retinal leakage(12 wk post DL-AAA administration)was established,anti-vascular endothelial growth factor(VEGF)(bevacizumab,ranibizumab and aflibercept)and anti-inflammatory(triamcinolone,TAA)drugs were tested for their efficacy after IVT administration.Fluorescein angiograms were scored before and after treatment following a novel grading system,developed for the DL-AAA rabbit model.RESULTS:Post DL-AAA administration,eyes were presented with moderate to severe retinal/choroidal inflammation which was accompanied by intense vitreous flare and presence of inflammatory cells in the vitreous humor.Retinal hemorrhage was restricted to the tips of neo-retinal vessels.FA revealed maximum retinal vascular leakage at 2 wk after DL-AAA injection and then persisted as evidenced by stable mean FA scores in weeks 8 and 12.Retinal vascular angiographic and tomographic features were stable and consistent up to 36 mo among two different staggers induced for RNV at two different occasions.Day 7,mean FA scores showed that 1μg/eye of bevacizumab,ranibizumab,aflibercept and 2μg/eye of TAA suppress 65%,90%,100%and 50%retinal vascular leakage,respectively.Day 30,bevacizumab and TAA continued to show 66%and 44%suppression while ranibizumab effect was becoming less effective(68%).In contrast,aflibercept was still able to fully(100%)suppress vascular leakage on day 30.On day 60,bevacizumab,ranibizumab and TAA showed suppression of 7%,12%,and 9%retinal vascular leakage,respectively,however,aflibercept continued to be more effective showing 50%suppression of vascular leakage.CONCLUSION:The DL-AAA rabbit model mimics RNV angiographic features like RNV and chronic retinal leakage.Based on these features the DL-AAA rabbit model provides an invaluable tool that could be used to test the therapeutic efficacy and duration of action of novel anti-angiogenic formulations,alone or in combination with anti-inflammatory compounds.     

Captopril抑制鼠视网膜新生血管的形成(英文)

目的:探讨Captopril对鼠视网膜新生血管形成的抑制作用。方法:将60只7d龄小鼠随机分为对照组(30只)和治疗组(30只),置于体积分数750±50mL/L高氧环境下饲养5d后回到正常空气环境中饲养,出氧箱后治疗组每天1次玻璃体腔内注射2.7mL/kg Captopril,对照组注射9g/L的氯化钠注射液2.7mL/kg,连续5d。两组小鼠均于17d处死并摘除眼球,采用ADP酶视网膜铺片、HE染色及免疫组织化学法分别观察视网膜血管的改变、计数视网膜新生血管内皮细胞核数及检测MMP-2、PEDF蛋白的表达。结果:治疗组与对照组相比视网膜血管分布规则、分支良好、新生血管密度减少,且突破视网膜内界膜的血管内皮细胞核数目明显减少(P<0.05);治疗组MMP-2染色较对照组减弱,PEDF染色较对照组增强。结论:玻璃体腔内注射2.7mL/kg Captopril能够有效抑制高氧诱导下的小鼠视网膜新生血管形成, Captopril有望成为防治血管增生性视网膜病变的一种有效的方法。     

Inhibitory effect of captopril on retinal neovascularization in mice

AIM: To study the inhibitory effect of captopril on retinal neovascularization (RNV). METHODS: Sixty seven-day-old mice were randomly divided into treated group and control group with thirty mice in each group. These mice were exposed to 750 ± 50mL/L oxygen for 5 days and then to room air. The treated group had been injected captopril (2.7mL/kg), while control group had been injected 9g/L sodium chloride (2.7mL/kg) by intravitreal for 5 days. The mice were sacrificed at the 17th day after birth and the eyes were enucleated. Adenosine diphosphate-ase (ADPase) stained retina flat-mounts was performed to assess the retinal vascular profiles, Hematoxylin Eosin (HE) staining method was applied to count the number of new vascular cell nuclei and the expression of matrix metalloproteinase-2 (MMP-2) and pigment epithelium derived factor (PEDF) was detected by immunohistochemical method. · RESULTS: Comparing with control group, regular distributions, good branch and reduced density of RNV were observed in the treated group. The number of nucleus of new vessels vascular endothelial cells breaking through the internal limiting membrane was less in the treated group than in the control group ( <0.05). Stain of retinal MMP-2 was weaker in the treated group than in the control group and stain of retinal PEDF was stronger in the treated group than in the control group. CONCLUSION: Intravitreal injection of captopril (2.7mL/kg) may block the RNV in the oxygen-induced mouse model and the method may provide an effective method for preventing RNV.     

Angiogenesis and retinal diseases

Angiogenesis is the process involving the growth of new blood vessels from preexisting vessels which occurs in both physiologic and pathological settings. It is a complex process controlled by a large number of modulating factors, the pro-and antiangiogenic factors. The underlying cause of vision loss in proliferative retinal diseases, such as age-related macular degeneration and proliferative diabetic retinopathy, are increased vascular permeability and choroidal neovascularization, and vascular endothelial growth factor (VEGF) plays a central role in this process. VEGF is produced in the eye by retinal pigment epithelium (RPE) cells and is upregulated by hypoxia. There are four major biologically active human isoforms, of which VEGF165 is the predominant in the human eye and appears to be the responsible for pathological ocular neovascularization. Besides being a potent and specific mitogen for endothelial cells, VEGF increases vascular permeability, inhibits endothelial cells apoptosis, and is a chemoattractant for endothelial cell precursors. VEGF is not the only growth factor involved in ocular neovascularization. Basic fibroblast growth factor (bFGF), angiopoietins, pigment epithelium-derived factor (PEDF), and adhesion molecules also play a role in the pro- and antiangiogenic balance. Advances in the understanding of the bases of pathological ocular angiogenesis and identification of angiogenesis regulators have enabled the development of novel therapeutic agents. Anti-VEGF antibodies have been developed for intravitreal use, and other approaches are currently under investigation. These new drugs may be powerful tools for the treatment of the leading causes of irreversible blindness in people over age 65.     

碱性成纤维细胞生长因子与视网膜新生血管

碱性成纤维细胞生长因子（bFGF）是一种兼有促有丝分裂原．血管生长因子、分化因子及神经营养因子等多种功能的生物活性物质。bFGF在视网膜的多种细胞内均有表达，参与视网膜细胞的分化、增生及损伤修复以及视网膜新生血管（RNV）的形成。bFGF与糖尿病性视网膜病变、视网膜静脉阻塞、早产儿视网膜病变等多种RNV相关性疾病有关，但在RNV形成中的作用尚存在争议，与其他因子协同促RNV形成可能是bFGF主要的作用机制。就bFGF的生物学特性以及与RNV的关系作一综述。