抗VEGF药物玻璃体内注射治疗对早产儿视网膜病变神经系统发育的影响

早产儿视网膜病变(ROP)是以视网膜血管异常增生为主要病理特征的儿童致盲眼病。血管内皮生长因子(VEGF)是一种特异性刺激血管内皮细胞增生及新生血管形成的生长因子。早产儿视网膜局部缺血、缺氧环境促使眼内VEGF表达代偿性升高,进而诱导视网膜血管病理性生长。玻璃体内注射抗VEGF药物可抑制眼内VEGF的生物活性,从而延缓...     

胰岛素样生长因子-1与早产儿视网膜病变

早产儿视网膜病变(ROP)是儿童主要的致盲眼病之一。氧调节和非氧调节生长因子均参与ROP的发生。血管内皮生长因子(VEGF)是一种重要的氧调节因子,其在新生血管形成中的重要作用已逐渐被认识,而非氧调节生长因子(胰岛素样生长因子-1,IGF-1)可能与早产儿脱离子宫内环境有关。本文主要讨论IGF-1和VEGF在ROPⅠ、Ⅱ期病变中的作用,以期能在早期评价个体的ROP发生倾向,及早进行干预,降低ROP发生率。     

玻璃体内注射贝伐单抗治疗早产儿视网膜病变的临床进展

血管内皮细胞生长因子(VEGF)在早产儿视网膜病变(ROP)的发生过程中发挥重要作用.在ROP的新生血管增生阶段,应用抗VEGF类药物抑制VEGF可以阻断视网膜血管的异常增生.本文就抗VEGF类药物贝伐单抗(Avastin)单纯玻璃体内注射、玻璃体内注射联合视网膜光凝或玻璃体切除手术等不同方式治疗ROP的临床研究进行回顾,并就贝伐单抗治疗ROP的安全性评价进行汇总.     

肾素-血管紧张素系统阻滞剂预防早产儿视网膜病变研究

血管紧张素Ⅱ(AngⅡ)是肾素-血管紧张素系统(RAS)的主要效应产物和多种器官有效的生长因子.在早产儿视网膜病变(ROP)等缺血性视网膜病变中,RAS上调,视网膜RAS被激活,刺激具有促微血管渗漏、周细胞迁移、新生血管生成和纤维化功能的血管内皮生长因子(VEGF)等上调.对RAS的阻滞主要通过血管紧张素转换酶抑制剂和血管紧张素Ⅱ受体拮抗剂来实现.RAS阻滞剂在ROP的发生发展过程中可能具有防止和减弱病理性血管生成的作用.对RAS的阻断有望成为ROP的治疗途径.     

肾素-血管紧张素系统阻滞剂预防早产儿视网膜病变研究

血管紧张素Ⅱ(AngⅡ)是肾素-血管紧张素系统(RAS)的主要效应产物和多种器官有效的生长因子.在早产儿视网膜病变(ROP)等缺血性视网膜病变中,RAS上调,视网膜RAS被激活,刺激具有促微血管渗漏、周细胞迁移、新生血管生成和纤维化功能的血管内皮生长因子(VEGF)等上调.对RAS的阻滞主要通过血管紧张素转换酶抑制剂和血管紧张素Ⅱ受体拮抗剂来实现.RAS阻滞剂在ROP的发生发展过程中可能具有防止和减弱病理性血管生成的作用.对RAS的阻断有望成为ROP的治疗途径.     

肾素-血管紧张素系统阻滞剂预防早产儿视网膜病变研究

血管紧张素Ⅱ(AngⅡ)是肾素-血管紧张素系统(RAS)的主要效应产物和多种器官有效的生长因子.在早产儿视网膜病变(ROP)等缺血性视网膜病变中,RAS上调,视网膜RAS被激活,刺激具有促微血管渗漏、周细胞迁移、新生血管生成和纤维化功能的血管内皮生长因子(VEGF)等上调.对RAS的阻滞主要通过血管紧张素转换酶抑制剂和血管紧张素Ⅱ受体拮抗剂来实现.RAS阻滞剂在ROP的发生发展过程中可能具有防止和减弱病理性血管生成的作用.对RAS的阻断有望成为ROP的治疗途径.     

玻璃体腔注射抗VEGF药物治疗早产儿视网膜病变的研究进展

早产儿视网膜病变(ROP)是发生于早产儿的一种未成熟视网膜血管增殖性眼病，是一种严重的儿童致盲性眼病。视网膜激光光凝术是治疗ROP的经典方法，然而激光治疗是破坏性的，尤其是在ROP Ⅰ区病变的情况下，视网膜激光光凝治疗会引起严重的并发症。研究表明，血管内皮细胞生长因子(VEGF)在ROP发生及发展过程中具有关键作用，而玻璃体腔注射抗VEGF药物不仅能有效控制ROP，并且为视网膜继续发育争取了机会。本文就玻璃体腔内注射抗VEGF药物治疗ROP的治疗指征、药物筛选、注射部位、给药剂量、疗效观察以及并发症对其进行综述。     

早产儿视网膜病变发病机制及药物治疗的研究进展

早产儿视网膜病变(ROP)是发生于早产儿和低体重儿中的视网膜血管增生性病变,是儿童致盲的主要原因之一。研究ROP发生的危险因素、发病机制及药物干预治疗,对降低ROP的发生率和致盲率有着极其重要意义。近年来随着新生血管研究的深入,新生血管抑制剂用于预防及治疗ROP的研究也越来越多,本文拟对近年来有关ROP上述研究进展作一综述。     

早产儿视网膜病变抗VEGF治疗进展

早产儿视网膜病变(retinopathy of prematurity, ROP)是发生于早产儿的一种未成熟视网膜血管增生性眼病,是发展中及发达国家儿童致盲的主要因素。ROP的传统治疗方法是视网膜激光光凝或冷冻治疗,但凝固治疗可导致视网膜永久性破坏,存在发生视野缺损、高度近视等并发症风险。玻璃体腔注射抗血管内皮细胞生长因子(VEGF)药物治疗ROP后视网膜功能的发育比凝固治疗更趋向正常,再加上操作简便、耗时短等优点,玻璃体腔注射抗VEGF药物逐渐成为ROP的重要治疗方式; 在Ⅰ区ROP、Ⅱ区后部ROP和急进型ROP治疗中为首选治疗方式。但是抗VEGF药物治疗ROP所致的严重系统并发症、最低有效剂量及后期复发情况等问题尚待进一步研究。本文将对ROP抗VEGF治疗现状进行综述。     

抗眼底新生血管药物的研究进展

视网膜和脉络膜新生血管可引发玻璃体出血、视网膜下出血、牵引性视网膜脱离等,从而危害患眼视力。这类病变常见于老年性黄斑变性(age related macular degeneration,AMD)、糖尿病视网膜病变(diabetic retinopathy,DR)、视网膜静脉阻塞(retinal vein occlusions,RVO)、早产儿视网膜病变(retinopathy of prematurity,ROP)等眼底病。当前,药物治疗新生血管(neovscularization,NV)主要是针对NV生成的不同阶段抑制其生长。本文综述了目前已用于临床及正在进行临床试验的治疗眼底新生血管的药物。     

氧诱导视网膜病变鼠模型血管内皮 生长因子mRNA的表达

目的分析氧诱导视网膜病变动物模型血管内皮生长因子（VEGF）基因的调节规律，阐明早产儿视网膜病变（ROP）新生血管形成的可能机制。方法将36只7 d 龄C₅₇BL/6J幼鼠暴露在（75±2）% 浓度的高氧状态下5 d，随后在正常氧环境下5 d，作为氧诱导模型组；另24只同日龄幼鼠作为正常对照组。采用荧光素血管灌注及视网膜铺片法观察视网膜血管形态；半定量逆转录-聚合酶链反应(RP-PCR)观察各组VEGF mRNA的变化。结果氧诱导模型的视网膜血管形态特征为高氧状态下表层和深层血管的中心区出现无灌注，相对低氧状态下2 d后开始出现新生血管，其部位在中周部。RF-PCR结果显示，VEGF的表达与眼内新生血管的发生存在明确的时空对应关系，即高氧状态下，VEGF mRNA转录下降，相对低氧状态下，VEGF mRNA过度转录。结论缺氧是视网膜新生血管发生的主要原因；高氧之后的相对低氧使VEGF表达增加，可能会降低ROP新生血管的发生。(中华眼底病杂志,2005,21:292-295)     

Pathogenese der Retinopathia praematurorum

Retinopathy of prematurity (ROP) is a vascular disease of the eye unique to preterm infants. The distinctive feature of ROP is that is an illness of the still-maturing organism. Thus, an understanding of the normal fetal development of the retina is fundamental to understanding the pathogenesis of ROP. Animal models of ROP differ in important attributes, a fact that is important for interpretation of results. However, all models have in common the finding that ROP is a biphasic disease. In the first phase, relative hyperoxia results in vaso-obliteration and vessel loss. The second phase is characterized by hypoxia-induced neovascularization resulting in retinal detachment and blindness. Oxygen-dependent vascular endothelial growth factor (VEGF) and oxygen-independent insulin-like growth factor (IGF-1) have been identified as important factors in the pathogenesis of ROP. These findings suggest new therapeutic approaches. Substitution of IGF-1 during the first phase of the disease may help prevent vessel loss, and administration of anti-angiogenic substances during the second phase may prevent pathological neovascularization.     

Contrasting effect of estrogen on VEGF induction under different oxygen status and its role in murine ROP

PURPOSE: It has been reported that 17beta-estradiol (E2) may enhance the proliferation of bovine retinal vascular endothelial cells (BRECs) by increasing the expression of VEGFR-2 and VEGF. The hypothesis in the current study was that estrogen may contribute to fetal vascular development and the cessation of exposure to estrogen of premature infants on birth may have an inhibitory effect on retinopathy of prematurity (ROP). Because ROP is thought to develop under relative hypoxia after exposure to high-dose oxygen, this study was conducted to investigate how estrogen modulates hypoxia-induced VEGF in BRECs and mouse ROP. METHODS: Gene expression of VEGF and hypoxia-inducible factor (HIF)-1alpha were studied in BRECs, with or without E2, under normoxia and hypoxia (1% O2). A binding assay was performed to determine whether estrogen interferes with HIF-1-mediated induction of VEGF. In a mouse ROP model, effects of E2 were evaluated by avascular area, subsequent extraretinal neovascularization, and retinal expression of the VEGF gene, by administering E2 during hyperoxia (75% O2) and/or after exposure to room air. RESULTS: Hypoxia-induced VEGF mRNA in BRECs was reduced dose dependently by 1 to 100 nM E2. E2 reduced hypoxia-induced binding of HIF-1 to the VEGF promoter site and reduced the HIF-1alpha mRNA level. In mouse ROP, injection of E2 during hyperoxia increased retinal VEGF mRNA and reduced the retinal avascular area at the end of hyperoxia. E2 treatment during the normoxia that followed reduced VEGF mRNA and extraretinal neovascularization. Treatment with E2 throughout both periods significantly improved retinopathy. CONCLUSIONS: Estrogen may function as a significant modulator of the level of VEGF mRNA under different oxygen conditions and could serve as a prophylactic agent for ROP.     

Proteins with an endostatin-like domain in a mouse model of oxygen-induced retinopathy

Neovascularization in the retinopathy of prematurity (ROP) mouse eye is a self-limiting phenomenon. Free endostatin is known to be anti-angiogenic. In this study, we identified the localization of endostatin-like protein (ELP) sequences and investigated their possible role in this process. ROP was induced in C57Bl/6 mice and the eyes observed 1-11 days after termination of high oxygen supply (P13-P21). Sagittal sections and retinal flatmounts were double-stained with antibodies against a protein-sequence of endostatin, vascular endothelial growth factor (VEGF), lectin, and smooth-muscle alpha actin. The fluorescence was visualized by traditional and confocal microscopy. Intense staining for VEGF in the inner retina was limited to the early stages of neovascularization and diminished at P19-P21. In contrast, staining for ELPs appeared at P15 around the newly formed vessels and remained even after degeneration of their endothelial cells. Staining of the inner retinal vasculature for ELPs was restricted to P17-P19, the known maximum of the neovascular response. Outer retinal vessels did not show presence of ELPs at any time. Our study demonstrates that ELPs, absent at the beginning of neovascular sprouting, increases with the amount of neovascularization and thus, varies reciprocally to VEGF in the time period investigated. ELPs remain during the regression of the vessels and might therefore play an important role in the self-limiting process of ROP neovascularization.     

Colocalization of Tie2, angiopoietin 2 and vascular endothelial growth factor in fibrovascular membrane from patients with retinopathy of prematurity

PURPOSE: The tyrosine kinase receptor Tie2 and its ligands, the angiopoietins (Angs), play important roles in vascular integrity and neovascularization, modulating vascular endothelial growth factor (VEGF) activity. To elucidate the potential role of Angs and the Tie2 system in retinopathy of prematurity (ROP), we have investigated the expression of Angs, Tie2 and VEGF within fibroproliferative membranes in ROP. METHODS: Fibroproliferative membranes were obtained from 38 cases with stage 5 ROP at the time of vitrectomy. Membranes were fixed in formalin and embedded in paraffin. Each specimen was serially sectioned for immunohistochemistry. Polyclonal antibodies specific for Ang1, Ang2, Tie2 and VEGF were used for immunostaining. Immunoreactivity for von Willebrand factor (factor VIII) was also assessed to confirm the identity of vascular endothelial cells. RESULTS: Positive staining for Tie2 was observed in 23 of 38 specimens (60.5%). Tie2 was localized in vascularized regions of fibrovascular membranes and was co- expressed with VEGF and factor VIII. Ang2 stained positively in 18 of 38 (47.3%) serial sections where Tie2 was present, and was also co-expressed with VEGF and factor VIII. Ang1 was not generally observed in these specimens (3/38). CONCLUSIONS: VEGF and Ang2-Tie2 interactions may play an important role in the pathogenesis of ROP.     

The effects of oxygen stresses on the development of features of severe retinopathy of prematurity: knowledge from the 50/10 OIR model

The objective of this study is to determine growth factor expression and activation of signaling pathways associated with intravitreous neovascularization and peripheral avascular retina using a model of retinopathy of prematurity (ROP) relevant to today with oxygen monitoring in neonatal units. Studies using 50/10 oxygen-induced retinopathy (OIR) and 50/10 OIR+SO models were reviewed. Repeated fluctuations in oxygen increased retinal vascular endothelial growth factor (VEGF) even while peripheral avascular retina persisted and prior to the development of intravitreous neovascularization. Repeated fluctuations in oxygen increased VEGF₁₆₄ expression but not VEGF₁₂₀. Neutralizing VEGF bioactivity significantly reduced intravitreous neovascularization and arteriolar tortuosity without interfering with ongoing retinal vascularization. Repeated oxygen fluctuations led to retinal hypoxia and increased reactive oxygen species (ROS). Inhibiting ROS with NADPH oxidase inhibitor, apocynin, reduced avascular retina by interfering with apoptosis. Supplemental oxygen reduced retinal VEGF concentration and exacerbated NADPH oxidase activation to contribute to intravitreous neovascularization through activation of the JAK/STAT pathway. Oxygen stresses relevant to those experienced by preterm infants today trigger signaling of different pathways to cause avascular retina and intravitreous neovascularization. Increased signaling of VEGF appears important to the development of both avascular retina and intravitreous neovascularization.     

Colocalization of neuropilin-1 and Flk-1 in retinal neovascularization in a mouse model of retinopathy

PURPOSE. To investigate the mechanisms of the development of retinal neovascularization, the localizations of vascular endothelial (VEGF) receptors Flk-1 and neuropilin (NP)-1 mRNAs were examined. METHODS. The model of retinopathy of prematurity (ROP) was produced by ischemia-induced ocular neovascularization, by exposing postnatal day-7 mice to 75% oxygen for 5 days and then returning them to room air for 5 days. Retinal neovascularization was visualized by injection of fluorescein-dextran. Expression of Flk-1 and NP-1 mRNAs were examined by in situ hybridization with flatmount and serial sections of the retina. The localization of NP-1 was also confirmed by immunohistochemistry. Blood vessel patterns were characterized by immunohistochemical localization of von Willebrand factor (vWF). RESULTS. Flatmount in situ hybridization showed intense expression of NP-1 and Flk-1 mRNAs colocalized in the area of neovascularization. In situ hybridization of serial sections of the retina revealed that expression of Flk-1 and NP-1 was restricted to neovascularized vessels of the retina from ROP mice. CONCLUSIONS. The restricted expression of Flk-1 and NP-1 on neovascularized vessels suggests that these molecules may play important roles in retinal neovascularization. This is the first report of the colocalization of NP-1 and Flk-1 on neovascularized vessels of the retina from ROP mice.     

直接肾素阻滞剂Aliskiren预防早产儿视网膜病变

肾素作为肾素-血管紧张素系统（ｒｅｎｉｎ-ａｎｇｉｏｔｅｎｓｉｎｓｙｓｔｅｍ,ＲＡＳ）中上游生长因子,对ＲＡＳ链起着特异性限速的作用。在早产儿视网膜病变等缺血性视网膜病变中,ＲＡＳ上调,视网膜ＲＡＳ被激活,刺激血管内皮生长因子等上调,导致血管渗漏、血管内皮细胞增生和新生血管形成等血管病理性改变。直接肾素抑制剂Ａｌｉｓｋｉｒｅｎ作为阻断ＲＡＳ的新途径,在防止和减弱病理性血管生成的过程中发挥了明显作用。Ａｌｉｓｋｉｒｅｎ的应用有望成为早产儿视网膜病变的预防及治疗途径。     

Inhibition of oxygen-induced retinopathy in RTP801-deficient mice

PURPOSE: Ischemic proliferative retinopathy, which occurs as a complication of diabetes mellitus, prematurity, or retinal vein occlusion, is a major cause of blindness worldwide. In addition to retinal neovascularization, it involves retinal degeneration, of which apoptosis is the main cause. A prior report has described the cloning of a novel HIF-1-responsive gene, RTP801, which displays strong hypoxia-dependent upregulation in ischemic cells of neuronal origin, both in vitro and in vivo. Moreover, inducible overexpression of RTP801 promotes the apoptotic death of differentiated neuron-like PC12 cells and increases their sensitivity to ischemic injury and oxidative stress. The purpose of the study was to examine the potential role of RTP801 in the pathogenesis of retinopathy, using RTP801-deficient mice. METHODS: Wild-type and RTP801-knockout mice were used in a model of retinopathy of prematurity (ROP). Their retinas were collected at postnatal day (P)14 and P17. They were examined by fluorescein angiography and by analysis of VEGF expression, neovascularization, and apoptosis. RESULTS: The expression of RTP801 was induced in the wild-type retina after hypoxia treatment. The retinal expression of VEGF after transfer to normoxic conditions was similarly upregulated in both wild-type and knockout mice. Nevertheless, the retinas of the RTP801-knockout mice in an ROP model showed a significant reduction in retinal neovascularization (P < 0.0001) and in the number of apoptotic cells in the inner nuclear layer (P < 0.0001). CONCLUSIONS: In the absence of RTP801 expression, development of retinopathy in the mouse model of ROP was significantly attenuated, thus implying an important role of RTP801 in the pathogenesis of ROP.     

Specific involvement of SRC family kinase activation in the pathogenesis of retinal neovascularization

PURPOSE: Src family kinases (SFKs) are membrane-attached nonreceptor protein tyrosine kinases that link a variety of extracellular cues to intracellular signal pathways. The purpose of this study was to characterize the roles of SFKs in vascular endothelial growth factor (VEGF)-mediated retinal angiogenesis. METHODS: Primary rat retinal glial Müller cells and bovine and human retinal microvascular endothelial cells (RMECs) were used in the in vitro studies. A rat model of retinopathy of prematurity (ROP) was used in the in vivo studies. RESULTS: In vitro, SFKs were essential for hypoxia-induced VEGF expression in Müller cells and for VEGF signaling in RMECs. However, neither process required significant further phosphorylation of the SFK activation loop Tyr416. In vivo, in a rat model of ROP, a pronounced increase of retinal SFK Tyr416 phosphorylation was observed that was specifically associated with pathologic angiogenesis. These retinas also expressed significantly higher levels of VEGF than did those in healthy controls. Immunohistochemical analysis indicated that Müller cells were the major source of the elevated level of phospho-SFK Tyr416. Intravitreous injection of a selective SFK inhibitor, PP2, significantly reduced retinal VEGF and retinopathy in the ROP model, indicating that SFKs acted as important regulators in abnormal retinal angiogenesis. CONCLUSIONS: Together, these data suggest that SFK activation through a Tyr416-dependent mechanism may be an important factor in the pathogenesis of retinal neovascularization.