11-cis-retinal and Retinal-Neovascularization

Bombina variegata 8 (Bv8), also known as prokineticin-2 (PK-2), is a potent pro-angiogenic factor. However, its role in retinal neovascularization (RNV) remains unknown. In this study, we explored the role of Bv8 in the pathogenesis of RNV. We found that the expression of Bv8 was significantly increased in two different models of retinal neovascularization: the oxygen-induced retinopathy (OIR) mouse model and the rhodopsin promoter (rho)/VEGF transgenic mouse model. Neutralization of Bv8 by intravitreal injections of its antibody, not only inhibited retinal and subretinal neovascularization but also decreased the mRNA and protein levels of several pro-angiogenic factors. Our in vitro assay showed that recombinant human Bv8 (RhBv8) protein promoted human retinal microvascular endothelial cells (HRECs) tube-formation, cell proliferation and vascular endothelial growth factor receptor 1 (VEGFR1) and receptor 2 (VEGFR2) expression. Our findings suggest that Bv8 could be used as a novel target for the treatment of RNV-related ocular diseases.

Topics: Amphibian Proteins; Animals; Animals, Newborn; Cell Proliferation; Disease Models, Animal; Gene Expression Regulation; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neuropeptides; Oxygen; Promoter Regions, Genetic; Retinal Neovascularization; Retinal Vessels; Rhodopsin; RNA; Vascular Endothelial Growth Factor A

TM601 is a synthetic polypeptide with sequence derived from the venom of the scorpion Leiurus quinquestriatus that has anti-neoplastic activity. It has recently been demonstrated to bind annexin A2 on cultured tumor and vascular endothelial cells and to suppress blood vessel growth on chick chorioallantoic membrane. In this study, we investigated the effects of TM601 in models of ocular neovascularization (NV). When administered by intraocular injection, intravenous injections, or periocular injections, TM601 significantly suppressed the development of choroidal NV at rupture sites in Bruch's membrane. Treatment of established choroidal NV with TM601 caused apoptosis of endothelial cells and regression of the NV. TM601 suppressed ischemia-induced and vascular endothelial growth factor-induced retinal NV and reduced excess vascular permeability induced by vascular endothelial growth factor. Immunostaining with an antibody directed against TM601 showed that after intraocular or periocular injection, TM601 selectively bound to choroidal or retinal NV and co-localized with annexin A2, which is undetectable in normal retinal and choroidal vessels, but is upregulated in endothelial cells participating in choroidal or retinal NV. Intraocular injection of plasminogen or tissue plasminogen activator, which like TM601 bind to annexin A2, also suppressed retinal NV. This study supports the hypothesis that annexin A2 is an important target for treatment of neovascular diseases and suggests that TM601, through its interaction with annexin A2, causes suppression and regression of ocular NV and reduces vascular leakage and thus may provide a new treatment for blinding diseases such as neovascular age-related macular degeneration and diabetic retinopathy.

Topics: Angiogenesis Inhibitors; Animals; Animals, Newborn; Annexin A2; Apoptosis; Bruch Membrane; Capillary Permeability; Choroidal Neovascularization; Disease Models, Animal; Endothelial Cells; Female; Fibrinolysin; Humans; Infant, Newborn; Injections, Intravenous; Mice; Mice, Inbred C57BL; Mice, Transgenic; Promoter Regions, Genetic; Retinal Neovascularization; Retinal Vessels; Retinopathy of Prematurity; Rhodopsin; Scorpion Venoms; Tissue Plasminogen Activator; Vascular Endothelial Growth Factor A

In several disease states, abnormal growth of blood vessels is associated with local neuronal degeneration. This is particularly true in ocular diseases such as retinal angiomatous proliferation (RAP) and macular telangiectasia (MacTel), in which, despite the absence of large-scale leakage or hemorrhage, abnormal neovascularization (NV) is associated with local neuronal dysfunction. We describe here a retinal phenotype in mice with dysfunctional receptors for VLDL (Vldlr-/- mice) that closely resembles human retinal diseases in which abnormal intra- and subretinal NV is associated with photoreceptor cell death. Such cell death was evidenced by decreased cone and, to a lesser extent, rod opsin expression and abnormal electroretinograms. Cell death in the region of intraretinal vascular abnormalities was associated with an increased presence of markers associated with oxidative stress. Oral antioxidant supplementation protected against photoreceptor degeneration and preserved retinal function, despite the continued presence of abnormal intra- and subretinal vessels. What we believe to be novel, Müller cell-based, virally mediated delivery of neurotrophic compounds specifically to sites of NV was also neuroprotective. These observations demonstrate that neuronal loss secondary to NV can be prevented by the use of simple antioxidant dietary measures or cell-based delivery of neurotrophic factors, even when the underlying vascular phenotype is not altered.

Topics: Angiogenesis Inhibitors; Animals; Antioxidants; Aptamers, Nucleotide; Disease Models, Animal; Electroretinography; Gene Expression; Gene Expression Profiling; Gene Transfer Techniques; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Mice, Knockout; Nerve Growth Factors; Opsins; Oxidative Stress; Receptors, LDL; Retina; Retinal Cone Photoreceptor Cells; Retinal Neovascularization; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells; Retinitis Pigmentosa; Rhodopsin; Vascular Endothelial Growth Factor A

This study was designed to determine if low power laser therapy can achieve amelioration of vasoproliferation yet preserve useful vision in the treated area in a transgenic mouse model of retinal neovascularisation. The mice were anaesthetised and the pupils dilated for ERG and fundus fluorescein angiography on postnatal day 32. The left eyes were treated with approximately 85 laser spots (532 nm, 50 ms, 300 microm diameter) at a power level of 20 mW at the cornea. The eyes were examined using ERG and fluorescein angiography, one, four and six weeks later. Flat mounts of FITC-dextran infused retinas, retinal histology and PEDF immunohistochemistry was studied one or six weeks after laser treatment. In untreated eyes the expected course of retinal neovascularisation in this model was observed. However, retinal neovascularisation in the laser treated eye was significantly reduced. The laser parameters chosen produced only mild lesions which took 10-20 s to become visible. ERG responses were comparable between the treated and untreated eyes, and histology showed only partial loss of photoreceptors in the treated eyes. PEDF intensity corresponded inversely with the extent of neovascularisation. Low power panretinal photocoagulation can inhibit retinal neovascularisation and yet preserve partial visual function in this transgenic mouse model of retinal neovascularisation.

Topics: Animals; Disease Models, Animal; Electroretinography; Eye Proteins; Fluorescein Angiography; Immunohistochemistry; Laser Coagulation; Low-Level Light Therapy; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Growth Factors; Photoreceptor Cells, Vertebrate; Promoter Regions, Genetic; Retinal Neovascularization; Retinal Vessels; Rhodopsin; Serpins; Time Factors; Vascular Endothelial Growth Factor A; Vision Disorders; Vision, Ocular

This study compared the effects of intraocular injections of ranibizumab (RBZ) and bevacizumab (BVZ) in transgenic mouse models in which human vascular endothelial growth factor (VEGF) causes subretinal neovascularization (NV) or exudative retinal detachment.. Randomized trials in animal models.. Transgenic mice in which the rhodopsin promoter drives expression of human VEGF in photoreceptors (rho/VEGF mice) and double transgenic mice with doxycycline-inducible expression of human VEGF in photoreceptors (Tet/opsin/VEGF mice).. Rho/VEGF mice received intraocular injections of RBZ, BVZ, or vehicle, and after various time periods the area of subretinal NV was measured. Tet/opsin/VEGF mice were given an intraocular injection of RBZ, BVZ, or vehicle, and after 5 days of doxycycline treatment the presence or absence of retinal detachment was determined.. Area of subretinal NV per retina in rho/VEGF mice and the occurrence of retinal detachment in Tet/opsin/VEGF mice.. In rho/VEGF mice, intraocular injections of RBZ or BVZ strongly suppressed subretinal NV, but the duration of effect was greater for BVZ. Three injections of 10 microg of BVZ over the course of 2 weeks not only suppressed subretinal NV in the injected eye but also caused significant suppression in the fellow eye, indicating a systemic effect. In doxycycline-treated Tet/opsin/VEGF mice, intraocular injection of 10 microg of BVZ significantly reduced the incidence of exudative retinal detachment compared with injection of 10 microg of RBZ. Injection of 25 microg of BVZ reduced the incidence of retinal detachment in both eyes.. Intraocular injections of RBZ and BVZ had similar efficacy in rho/VEGF mice, but the duration of effect was greater for BVZ. In Tet/opsin/VEGF mice, in which expression levels of human VEGF are very high and the phenotype is severe, BVZ showed greater efficacy than RBZ. In both models, higher doses or repeated injections of BVZ, but not RBZ, resulted in a systemic effect. These data suggest that BVZ is not inferior to RBZ for treatment of subretinal NV in mice and is superior in a severe model. The systemic effects of BVZ after intraocular injection deserve further study and consideration of their potential consequences.. Proprietary or commercial disclosure may be found after the references.

Topics: Angiogenesis Inhibitors; Animals; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Bevacizumab; Doxycycline; Gene Expression Regulation; Injections; Mice; Mice, Transgenic; Microscopy, Fluorescence; Ranibizumab; Retinal Detachment; Retinal Neovascularization; Rhodopsin; Vascular Endothelial Growth Factor A; Vitreous Body

To investigate early retinal changes in a vascular endothelial growth factor (VEGF) transgenic mouse (tr029VEGF; rhodopsin promoter) with long-term damage that mimics nonproliferative diabetic retinopathy (NPDR) and mild proliferative diabetic retinopathy (PDR).. Rhodopsin and VEGF expression was assessed up to postnatal day (P)28. Vascular and retinal changes were charted at P7 and P28 using sections and wholemounts stained with hematoxylin and eosin or isolectin IB4 Griffonia simplicifolia Samples were examined using light, fluorescence, and confocal microscopy.. Rhodopsin was detected at P5 and reached mature levels by P15; VEGF protein expression was transient, peaking at P10 to P15. In wild-type (wt) mice at P7, vessels had formed in the nerve fiber/retinal ganglion cell layer and showed a centroperipheral maturational gradient; some capillaries had formed a second bed on the vitread side of the inner nuclear layer (INL). By P28, the retinal vasculature had three mature capillary beds, the third abutting the sclerad aspect of the INL. In tr029VEGF mice, capillary bed formation was accelerated compared with that in wt, with abnormal vessels extending to the sclerad side of the INL by P7 and abnormally penetrating the photoreceptors by P28. Compared with P7, vascular lesions were more numerous at P28 when capillary dropout was also evident. At both stages, retinal layers were thinned most where abnormal vessel growth was greatest.. Concomitant damage to the vasculature and neural retina at early stages in tr029VEGF suggest that both tissues are affected, providing opportunities to examine early cellular events that lead to long-term disease.

Topics: Animals; Capillary Permeability; Diabetic Retinopathy; Disease Models, Animal; Fluorescein Angiography; Immunoenzyme Techniques; Mice; Mice, Transgenic; Microscopy, Confocal; Nerve Fibers; Retina; Retinal Ganglion Cells; Retinal Neovascularization; Retinal Vessels; Reverse Transcriptase Polymerase Chain Reaction; Rhodopsin; RNA, Messenger; Up-Regulation; Vascular Endothelial Growth Factor A

Topics: Animals; Disease Models, Animal; Humans; Mice; Mice, Transgenic; Microscopy, Confocal; Retina; Retinal Neovascularization; Rhodopsin; Time Factors; Vascular Endothelial Growth Factor A

Transgenic mice with vascular endothelial growth factor (VEGF) driven by the rhodopsin promoter (rho/VEGF mice) develop neovascularization that originates from the deep capillary bed of the retina and grows into the subretinal space. In rho/VEGF mice, VEGF expression in photoreceptors begins between postnatal days 5 and 7, the period when the deep capillary bed is developing. An important question is whether or not the developmental stage of the deep capillary bed is critical for occurrence of neovascularization. Also, although rho/VEGF mice are extremely useful for the study of ocular neovascularization, there are some applications for which the early onset of VEGF expression is a disadvantage. In this study, we used the reverse tetracycline transactivator (rtTA) inducible promoter system coupled to either the rhodopsin or interphotoreceptor retinoid-binding protein (IRBP) promoter to control the time of onset of VEGF transgene expression in photoreceptors. In the absence of doxycycline, adult double-transgenic rho/rtTA-TRE/VEGF or IRBP/rtTA-TRE/VEGF mice showed little VEGF transgene expression and no phenotype. The addition of doxycycline to the drinking water resulted in prominent transgene expression and evidence of neovascularization within 3 to 4 days. Like rho/VEGF mice, the neovascularization originated from the deep capillary bed of the retina, but it was more extensive and caused outer retinal folds followed by total retinal detachment. Real-time polymerase chain reaction and enzyme-linked immunosorbent assay demonstrated that the mice with inducible expression of VEGF that developed retinal detachment had much higher ocular levels of VEGF mRNA and protein compared to rho/VEGF mice that manifest a much milder phenotype. These data demonstrate that regardless of developmental stage of the vascular bed, increased expression of VEGF in the retina is sufficient to cause neovascularization, and high levels of expression cause severe neovascularization and traction retinal detachment. Mice with inducible expression of VEGF in the retina provide a valuable new model of ocular neovascularization.

Topics: Animals; Anti-Bacterial Agents; Doxycycline; Endothelial Growth Factors; Gene Expression Regulation; Humans; Lymphokines; Mice; Mice, Transgenic; Phenotype; Promoter Regions, Genetic; Recombinant Fusion Proteins; Retina; Retinal Detachment; Retinal Neovascularization; Rhodopsin; Statistics as Topic; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

To determine the earliest changes that occur in the retina after the onset of ectopic expression of vascular endothelial growth factor (VEGF) by photoreceptors in transgenic mice, to characterize the development of neovascularization (NV), and to determine the feasibility of using these mice to test the efficacy of antiangiogenic agents.. The time course of expression of VEGF transgene mRNA was determined by reverse transcription-polymerase chain reaction (RT-PCR). Histopathologic changes in the retina were investigated by light and electron microscopy and immunocytochemistry. Standard and confocal fluorescence microscopy and image analysis were used to evaluate NV in retinal whole mounts.. VEGF transgene mRNA was first detected in the retina by RT-PCR on postnatal day 6 (P6) and increased over the next several days to reach a constant steady-state level between P14 and P21. Abnormal cells were seen in the outer nuclear layer on P10 and among photoreceptors on P14; by P18 there were cell aggregates in the subretinal space with evidence of lumen formation. The invading cells were demonstrated to be endothelial cells by staining with an endothelial cell-specific lectin. Whole mounts of retinas perfused with fluorescein-labeled dextran showed a similar sequence of events, with sprouts from retinal vessels in the deep capillary bed seen on P14 and vessels reaching the subretinal space by P18. Confocal and standard fluorescence microscopy and changes in the number and area of neovascular lesions in the subretinal space over time measured by image analysis suggest gradual enlargement and coalescence of vascular complexes. The subretinal NV was progressively engulfed by the retinal pigmented epithelium. Invasion of blood vessels from the choroid was not identified in any specimen.. These data support the feasibility of using rhodopsin-VEGF transgenic mice to study tissue-specific aspects of NV in the retina and to test antiangiogenic agents for inhibition of intraretinal and subretinal NV.

Topics: Animals; DNA Primers; Endothelial Growth Factors; Endothelium, Vascular; Fluorescent Antibody Technique, Indirect; Immunohistochemistry; Lymphokines; Mice; Mice, Transgenic; Microscopy, Confocal; Photoreceptor Cells; Polymerase Chain Reaction; Retinal Neovascularization; Retinal Vessels; Rhodopsin; RNA, Messenger; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Basic fibroblast growth factor (FGF2) is constitutively expressed in the retina and its expression is increased by a number of insults, but its role in the retina is still uncertain. This study was designed to test the hypothesis that altered expression of FGF2 in the retina affects the development of retinal neovascularization. Mice with targeted disruption of the Fgf2 gene had no detectable expression of FGF2 in the retina by Western blot, but retinal vessels were not different in appearance or total area from wild-type mice. When FGF2-deficient mice were compared with wild-type mice in a murine model of oxygen-induced ischemic retinopathy, they developed the same amount of retinal neovascularization. Transgenic mice with a rhodopsin promoter/Fgf2 gene fusion expressed high levels of FGF2 in retinal photoreceptors but developed no retinal neovascularization or other abnormalities of retinal vessels; in the ischemic retinopathy model, they showed no significant difference in the amount of retinal neovascularization compared with wild-type mice. These data indicate that FGF2 expression is not necessary nor sufficient for the development of retinal neovascularization. This suggests that agents that specifically antagonize FGF2 are not likely to be useful adjuncts in the treatment of retinal neovascularization and therapies designed to increase FGF2 expression are not likely to be complicated by retinal neovascularization.

Topics: Animals; Disease Models, Animal; DNA Primers; Fibroblast Growth Factor 2; Humans; Immunoenzyme Techniques; Infant, Newborn; Mice; Mice, Knockout; Mice, Transgenic; Polymerase Chain Reaction; Recombinant Fusion Proteins; Retina; Retinal Neovascularization; Retinal Vessels; Retinopathy of Prematurity; Rhodopsin

Neovascularization (NV) of the retinal pigment epitheium (RPE) by retinal capillaries following degeneration and loss of photoreceptor cells is a widely recognized phenomenon in rodents. NV of the RPE usually occurs several weeks to months after the loss of photoreceptor cells. We have observed that NV of the RPE occurs much earlier in a line of P23H mutant rhodopsin transgenic mice than in most other mice and rats that have been previously examined. To compare the temporal course of RPE NV in P23H mice with that of two other retinal degeneration mutants with the same time course of photoreceptor cell loss, we have quantified the number of retinal capillaries in the RPE of P23H and Q344ter mutant rhodopsin transgenic mice and retinal degeneration (rd/rd) mice at ages ranging from postnatal day (P) 20-400. Retinal capillary profiles located within the RPE were already present as early as P20 in the P23H retinas, and although these usually were located where most photoreceptor nuclei were missing, they occasionally were found where 1-2 rows of photoreceptor nuclei were still present. The maximal incidence was found in P23H retinas at P100. By contrast, NV of the RPE in rd/rd and Q344ter mice occurred much later. In rd/rd, a significant number of capillary profiles was not seen in the RPE until about P130, and not until about P180 in Q344ter. Both showed maximal incidence at about P240. In all three mutants, an apparent regression of the capillaries occurred following the peak, with that in the P23H mice preceeding the other two mutants. The findings suggest that the P23H mutant rhodopsin transgenic mouse may be a useful model for studying the regulation of NV in the outer retina.

Topics: Aging; Animals; Capillaries; Mice; Mice, Transgenic; Mutation; Photoreceptor Cells, Vertebrate; Pigment Epithelium of Eye; Retinal Neovascularization; Rhodopsin