鼠角膜碱烧伤后新生淋巴管上血管内皮生长因子受体-3的表达和意义

目的探讨鼠角膜碱烧伤后血管内皮生长因子受体-3(VEGFR-3)在新生淋巴管上的表达和意义,进一步证实角膜新生淋巴管的存在。方法在大鼠角膜上制作碱烧伤模型,应用免疫组化法检测第3、5、7天角膜中VEGFR-3蛋白的表达。电镜观测伤后第5、7、10、14天角膜新生淋巴管的情况。结果碱烧伤后,大鼠角膜组织中VEGFR-3表达从第3天开始明显上升,并于第5天达到最高峰,伤后第14天出现新生淋巴管。结论角膜碱烧伤后有新生淋巴管长入,VEGFR-3可能成为抑制角膜新生淋巴管的一个新靶点。     

血管内皮生长因子及其受体在眼科的应用研究进展

眼部新生血管的形成是一个及其复杂的病理生理过程,受多种因子的调节,目前血管内皮生长因子（vascular endothelial growth factor,VEGF）被认为是新生血管形成过程中关键性因子之一.已发现的血管内皮生长因子包括：VEGF-A、VEGF-B、VEGF-C、VEGF-D、VEGF-E、VEGF-F以及胎盘生长因子（placenta growth factor,PIGF）;VEGF受体（VEGF receptor,VEGFR）包括：VEGFR-1、VEG-FR-2、VEGFR-3.各受体可被不同或相同的VEGF激活、调控着不同的生理功能,其中对VEGF-A及其受体的研究最为深入.基于VEGF-A及其受体对新生血管不同作用位点和方式的研究,各种药物应运而生,使临床针对眼部新生血管性疾病的用药和治疗方案也发生了革命性的改变.但随着对VEGF家族及其受体的深入研究,逐渐发现VEGF家族中的其他成员,如：VEGF-B等与VEGF-A的作用靶器官及作用机制有很大差别.本文就VEGF家族中各成员及其受体的作用机制和功能以及目前抗VEGF的相关药物的种类、临床应用和研究进展进行综述.     

上皮缺损诱导角膜新生血管小鼠模型中VEGF与sFlt-1变化趋势的实验研究

目的观察小鼠角膜上皮缺损与角膜新生血管发生发展的关系，初步探讨新生血管发生发展过程中血管内皮生长因子（vascular endothelial growth factor，VEGF）与血管内皮生长因子可溶性受体（soluble VEGF receptor-1，sFlt-1）含量的变化趋势。方法正常成年雄性昆明小鼠294只，平均分为2组，分别接受角膜缘损伤加角膜上皮刮除（A组）和单纯角膜上皮刮除（B组）2种处理，干预后1、3、5、7、10、14d取角膜，分别行苏木素-伊红（hematoxylin eosin，HE）及过碘酸-希夫染色，铺片，免疫荧光标记血管内皮细胞，非变性蛋白印迹分析各时间点结合态和游离态VEGF蛋白含量，实时定量聚合酶链反应分析对应时间。sFlt-1信使核糖核酸（message ribonuclei cacid，mRNA）的表达强度。结果两组均成功诱导角膜新生血管。除第14天外，A组各时间点新生血管面积均高于B组，但前者上皮修复延迟，早期炎性细胞浸润程度亦较高，晚期角膜部分结膜化。A组各时间点VEGF总蛋白及游离蛋白含量均明显高于B组；sFlt-1 mRNA表达于早中期下降而后期上升。结论持续一定时间的角膜上皮缺损可相对减少sFlt-1的表达，增加游离VEGF，诱导血管生成；角膜缘损伤通过加重上皮缺损程度，增加血管形成。（中国眼耳鼻喉科杂志，2009，9：80—82）     

血管内皮细胞生长因子在病变角膜中的表达

角膜新生血管形成严重危害视力，也是角膜移植排斥反应的高危因素之一。血管内皮细胞生长因子（vascular endothelial growth factor ,VEGF）是一种重要的促血管生成因素。本文探讨VEGF与角膜新生血管化的关系。     

角膜碱烧伤后VEGF的表达与新生血管的关系

目的研究碱烧伤后角膜血管内皮生长因子（vascular endothelial growthfactor，VEGF）的表达与角膜新生血管化的关系。方法30只Sprague-Dawleg（SD）大鼠碱烧伤，诱导角膜新生血管模型。碱烧伤后不同时间形态学分析来评价角膜新生血管的情况，免疫组化及Westem blot评价角膜VEGF的表达。结果角膜碱烧伤后24hVEGF的表达开始增高，伤后4d达高峰，伤后7d VEGF的表达下降，14d后显著下降。碱烧伤后，角膜新生血管与VEGF的表达呈明显的平行关系。结论碱烧伤后大鼠角膜VEGF的表达水平与新生血管的形成有相关性，并在其中发挥重要作用。     

大鼠角膜碱烧伤后角膜淋巴管生成及VEGF-C和VEG-FR-3的表达

目的:研究大鼠角膜碱烧伤后角膜淋巴管生成及VEGF-C和VEGFR-3的表达。方法:制作角膜碱烧伤模型,应用免疫组化方法检测正常角膜及烧伤后1,3,5,7,14,21,28d角膜组织中VEGF-C和VEGFR-3的表达,免疫组化LYVE-1(淋巴管内皮特异标记物)染色观察角膜中淋巴管生成情况,电镜观察烧伤后14d角膜新生淋巴管状况。结果:角膜碱烧伤后,VEGF-C和VEGFR-3的表达明显升高,烧伤后3d,角膜中出现淋巴管。结论:角膜碱烧伤后新生淋巴管生成伴VEGF-C和VEGFR-3高表达。     

大鼠角膜化学伤后PEDF和VEGF的不平衡表达

目的比较硝酸银化学伤后大鼠角膜和正常角膜色素上皮衍生因子（PEDF）和血管内皮生长因子（VEGF）表达水平，揭示两者与角膜新生血管的相关性。方法10只大鼠左眼角膜硝酸银化学伤后为实验组，右眼为正常对照组，伤后15d行免疫组织化学法定位及Western blot定量检测样本角膜PEDF、VEGF等的表达。结果免疫组织化学检查：实验组角膜VEGF、碱性成纤维细胞生长因子（bFGF）强表达，PEDF未见表达或弱表达。正常组角膜PEDF高表达，VEGF弱表达，bFGF几乎不表达。Western Blot分析：实验组角膜PEDF表达明显下降（t=8．0049，P〈0．01），VEGF表达显著升高（t=48．3637，P〈0．01）。结论角膜严重化学伤后新生血管抑制因子PEDF破坏，刺激因子VEGF产生增加，PEDF／VEGF比值降低，角膜血管新生。     

青蒿琥酯对大鼠角膜新生血管的影响

目的研究青蒿琥酯（artesunate）对大鼠角膜新生血管形成的作用。方法采用碱烧伤诱导大鼠角膜新生血管模型，将65只SD大鼠随机分成正常对照组5只（5眼）、角膜新生血管对照组30只（30眼）、青蒿琥酯球结膜下注射组30只（30眼），比较第14d角膜新生血管生长的长度和面积，并分别在烧伤后第1、3、5、7、10、14d用免疫组织化学染色的方法检测血管内皮生长因子（VEGF）、核因子κB（NF—κB）的表达。结果青蒿琥酯球结膜下注射显著抑制了角膜新生血管的生长，免疫组织化学染色VEGF、NF-κB在正常角膜上皮基底部有弱表达，在新生血管对照组有明显增强，青蒿琥酯球结膜下注射组表达明显减弱。结论青蒿琥酯球结膜下注射可以有效抑制角膜新生血管的生长，其治疗机制可能是抑制VEGF、NF—κB的表达。     

血管内皮生长因子及其受体在病变角膜的表达和临床意义的探讨

目的：探讨血管内皮生长因子（vacular endothelial growth factor,VEGF)及其受体flt-l在各种病变角膜的表达和可能的作用。方法：收集正常周边角膜和角膜缘组织11例和各种病变的角膜标本32例。冰冻切片,用免疫组织化学方法检查标本内VEGF及其flt-1,分析其VEGF的表达与临床表现的关系。结果：VEGF在血管化和非血管化角膜标本均为阳性,在角膜上皮和病变基质表达较强;flt-l在大多数标本呈现阳性反应。在基质和内皮病变角膜VEGF表达高于正常角膜的表达（P＜0．05）,在浸润炎症细胞和增殖组织中的表达与角膜混浊程度、新生血管面积呈正相关（P＜0．05）。结论：各种病变角膜均表达了VEGF及其受体,VEGF在角膜损伤的修复和新生血管化可能起着重要作用。     

Corneal lymphangiogenesis: evidence,mechanisms, and implications for corneal transplant immunology

PURPOSE: The normal cornea is devoid of blood and lymphatic vessels but can become vascularized secondary to a variety of corneal diseases and surgical manipulations. Whereas corneal (hem)angiogenesis, i.e., the outgrowth of new blood vessels from preexisting limbal vessels, is obvious both clinically and histologically, proof of associated corneal lymphangiogenesis has long been hampered by invisibility and lack of specific markers. This has changed with the recent discovery of the lymphatic endothelial markers vascular endothelial growth factor receptor 3, LYVE-1 (a lymphatic endothelium-specific hyaluronan receptor), Prox 1, and Podoplanin. METHODS: We herein summarize the current evidence for lymphangiogenesis in the cornea and describe its molecular markers and mediators. Furthermore, the pathophysiologic implications of corneal lymphangiogenesis for corneal transplant immunology are discussed. RESULTS: Whereas corneal angiogenesis in vascularized high-risk beds provides a route of entry for immune effector cells to the graft, lymphangiogenesis enables the exit of antigen-presenting cells and antigenic material from the graft to regional lymph nodes, thus inducing alloimmunization and subsequent graft rejection. CONCLUSIONS: Antilymphangiogenic strategies may improve transplant survival both in the high- and low-risk setting of corneal transplantation.     

Lymphatic vessels in vascularized human corneas: immunohistochemical investigation using LYVE-1 and podoplanin

PURPOSE: To determine whether lymphatic vessels exist in vascularized human corneas, by using immunohistochemistry with novel markers for lymphatic endothelium. METHODS: Human corneas exhibiting neovascularization secondary to keratitis, transplant rejection, trauma, and limbal insufficiency (n = 21) were assessed for lymphatic vessel content by conventional transmission electron microscopy and by immunostaining and immunoelectron microscopy with antibodies specific for the lymphatic endothelial markers, lymphatic vessel endothelial hyaluronan receptor (LYVE-1) and the 38-kDa integral membrane glycoprotein podoplanin. In addition, corneas were stained for the lymphangiogenic growth factor VEGF-C, and its receptor VEGFR3 by immunohistochemistry and in situ RNA hybridization, respectively. RESULTS: Thin-walled, erythrocyte-free vessels staining with lymphatic markers (LYVE-1 and podoplanin) were found to constitute 8% of all vessels, to be more common in the early course of neovascularization, to be always associated with blood vessels and stromal inflammatory cells, and to correlate significantly with the degree of corneal hemangiogenesis (r = 0.6; P = 0.005). VEGF-C, VEGFR3, podoplanin, and LYVE-1 colocalized on the endothelial lining of lymphatic vessels. With immunogold labeling, LYVE-1 and podoplanin antigen were found on endothelial cells lining vessels with ultrastructural features of lymph vessels. CONCLUSIONS: Immunohistochemistry with novel lymph-endothelium markers and ultrastructural analyses indicate the existence of lymphatic vessels in vascularized human corneas. Human corneal lymphangiogenesis appears to be correlated with the degree of corneal hemangiogenesis and may at least partially be mediated by VEGF-C and its receptor VEGFR3.     

高危角膜移植大鼠排斥反应及VEGF-C/D表达的研究

目的：探讨鼠角膜碱烧伤后VEGF-C/D的表达和意义,以及新生淋巴管在高危角膜移植后排斥反应中的作用。
　　方法：制作角膜碱烧伤模型,取不同时间段角膜进行电镜观察,观察角膜血管化情况;采用免疫组织化学方法检测l、3、5、7、14、28 d角膜组织VEGF-C/D及VEGFR-3的表达;并在角膜中仅有血管(A组),同时存在新生血管及新生淋巴管(B组),新生淋巴管消退期(C组),角膜新生血管消退期(D组)以及正常组(N 组)进行穿透性角膜移植,比较不同角膜植片的排斥反应指数( rejection index, RI)值及存活时间。
　　结果：电镜观察发现,在碱烧伤后第7d时鼠角膜出现新生血管,未出现新生淋巴管,在碱烧伤2 wk时出现新生血管的同时出现淋巴管,5wk时无明显的新生淋巴管,8wk时新生血管逐渐消退;大鼠角膜组织中 VEGF-C/D 及VEGFR-3的表达从第3 d开始明显上升,并于第5 d达到最高峰。角膜移植后N、A、B、C、D组的植片平均存活时间分别为14.25±0.62、9.35±1.02、5.06±1.13、8.71±0.83、9.44±1.05d。组间比较发现,B组植片平均存活时间显著性缩短(P<0.05),A、C、D的存活时间均显著性延长(P<0.05)。
　　结论：角膜碱烧伤后存在VEGF-C/D及VEGFR-3的高表达,而且新生淋巴管能加速高危角膜移植后的免疫排斥反应。     

Vascular Endothelial Growth Factor Receptor-3 Mediates Induction of Corneal Alloimmunity

There are no studies so far linking molecular regulation of lymphangiogenesis and induction of adaptive immunity. Here, we show that blockade of vascular endothelial growth factor receptor-3 (VEGFR-3) signaling significantly suppresses corneal antigen-presenting (dendritic) cell trafficking to draining lymph nodes, induction of delayed-type hypersensitivity and rejection of corneal transplants. Regulating the function of VEGFR-3 may therefore be a mechanism for modulating adaptive immunity in the periphery.     

Effect of itraconazole on the cornea in a murine suture model and penetrating keratoplasty model

AIM: To investigate the anti-(lymph)angiogenic and/or anti-inflammatory effect of itraconazole in a corneal suture model and penetrating keratoplasty (PK) model. METHODS: Graft survival, corneal neovascularization, and corneal lymphangiogenesis were compared among itraconazole, amphotericin B, dexamethasone, phosphate buffered saline (PBS) and surgery-only groups following subconjunctival injection in mice that underwent PK and corneal suture. Immunohistochemical staining and analysis were performed in each group. Real-time polymerase chain reaction (RT-PCR) was performed to quantify the expression of inflammatory cytokines (TNF-alpha, IL-6) and vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGFR-2, and VEGFR-3. RESULTS: In the suture model, the itraconazole group showed less angiogenesis, less lymphangiogenesis, and less inflammatory infiltration than the PBS group (all P<0.05). The itraconazole group showed reduced expression of VEGF-A, VEGFR-2, TNF-alpha, IL-6 than the PBS group (all P<0.05). In PK model, the two-month graft survival rate was 28.57% in itraconazole group, 62.50% in dexamethasone group, 12.50% in PBS group, 0 in amphotericin B group and 0 in surgery-only group. Graft survival in the itraconazole group was higher than that in the amphotericin, PBS and surgery-only group (P=0.057, 0.096, 0.012, respectively). The itraconazole group showed less total angiogenesis and lymphangiogenesis than PBS group (all P<0.05). CONCLUSION: Itraconazole decrease neovascularization, lymphangiogenesis, and inflammation in both a corneal suture model and PK model. Itraconazole has anti-(lymph)-angiogenic and anti-inflammatory effects in addition to its intrinsic antifungal effect and is therefore an alternative treatment option in cases where steroids cannot be used.     

Combined blockade of VEGFR-3 and VLA-1 markedly promotes high-risk corneal transplant survival

PURPOSE. High-risk corneal transplantation refers to grafting performed on inflamed and highly vascularized host beds. It represents a clinical dilemma because the rejection rate can be as high as 90%, irrespective of current treatment modalities. This study was conducted to investigate whether combined blockade of VEGFR-3 (vascular endothelial growth factor receptor-3) and VLA-1 (very late antigen-1) promotes high-risk transplant survival and how it correlates with corneal lymphangiogenesis and hemangiogenesis before and after transplantation. METHODS. High-risk corneal transplantation was performed between normal C57BL/6 (donor) and inflamed BALB/c (recipient) mice. The recipients were randomized to receive intraperitoneal injections of VEGFR-3 and VLA-1-neutralizing antibodies or their controls twice a week for up to 8 weeks after transplantation. Corneal grafts were evaluated by ophthalmic slit-lamp biomicroscopy and analyzed by Kaplan-Meier survival curve. Additionally, whole-mount corneas before and after transplantation were examined by immunofluorescent microscopic assays, and the correlation between lymphatic or blood vessel distribution and transplant outcome was analyzed. RESULTS. The combined blockade markedly promotes 90% survival of high-risk transplants. This strategy specifically modified host beds by selective inhibition of lymphangiogenesis but not hemangiogenesis. A strong correlation was also identified between high-risk transplant rejection and severe lymphatic invasion reaching the donor-graft border. CONCLUSIONS. These novel findings not only provide a new and potentially powerful strategy to promote high-risk transplant survival, they also confirm a critical role of high-degree lymphangiogenesis in mediating high-risk transplant rejection. Results from this study may also shed new light on our understanding and management of other lymphatic- and immune-related diseases in general.     

Lack of lymphangiogenesis despite coexpression of VEGF-C and its receptor Flt-4 in uveal melanoma

PURPOSE: Because lymphatic vessels are absent from the normal eye and because uveal melanomas are presumed to spread by a hematogenous route in the absence of tumor exposure to conjunctival lymphatics, this study was undertaken to investigate the presence of lymphatic vessels in primary uveal melanomas. METHODS: The presence of lymphatics in 2 control eyes and in 33 primary uveal, 10 primary cutaneous, and 3 metastatic cutaneous melanomas was evaluated by using a double-immunostaining protocol that differentially highlights blood and lymphatic vasculature. In addition, 14 uveal melanomas were immunostained for the lymphatic growth factor vascular endothelial growth factor (VEGF)-C (with anti-VEGF-C polyclonal antibodies [pAbs]), its receptors Flt-4 (with monoclonal antibody [mAb] 9D9) and KDR (with anti-KDR mAb [Clone KDR-2]), and the hemangiogenic factor VEGF-A (with anti-VEGF pAbs). RESULTS: Lymphatics were not detected in normal eyes or in uveal melanoma. As a consequence, signs of lymphangiogenesis were not present. There was coexpression of VEGF-C with Flt-4 and KDR in 6 (43%) of the 14 melanomas. Staining for VEGF-A was completely negative in 25 uveal melanomas analyzed. CONCLUSIONS: The strictly hematogenous metastasis of primary uveal melanomas is explained by the absence of lymphatics in and around the tumor. The current data suggest that, in the presence of endothelial Flt-4, VEGF-C expression is not sufficient to induce lymphangiogenesis from preexisting blood vessels in human cancer.