Choroidal Flat Mounts Research Articles

Baicalin Attenuates Laser-Induced Choroidal Neovascularization

Purpose: To determine whether intravitreally-injected baicalin inhibits the growth of choroidal neovascularization (CNV) experimentally induced via laser photocoagulation through analysis of angiogenic factors.Materials and methods: Six CNVs were induced in the left eyes of 8-week-old male Brown Norway rats. Immediately after the induction of CNV, 4 μl of baicalin solution (0.1, 1 or 5 nmol) and 4 μl of a solution containing 100 μg of bevacizumab were slowly injected into the vitreous cavity under direct observation with an operating microscope. At 14 days after CNV induction, fluorescein angiography (FA) was performed, and choroidal flat mounts were produced for quantitative assessment of CNV. The levels of the anti-angiogenic proteins vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and matrix metalloproteinase-2 (MMP-2) were determined via Western blot analysis.Results: FA of bevacizumab- and baicalin-treated rats showed significantly reduced CNV and leakage from the CNV lesions compared to control rats at day 14. Choroidal flat mounts revealed that baicalin inhibited the growth of CNV lesions in a dose-dependent manner. Western blot analysis demonstrated that baicalin significantly attenuated the up-regulation of VEGF, PDGF and MMP-2.Conclusion: Baicalin suppressed laser-induced CNV formation in rats. These results suggest that baicalin should be considered as a candidate drug for treating exudative age-related macular degeneration.

Bone Marrow Transplantation Transfers Age-Related Susceptibility to Neovascular Remodeling in Murine Laser-Induced Choroidal Neovascularization

Neovascular remodeling (NVR), the progression of small capillaries into large-caliber arterioles with perivascular fibrosis, represents a major therapeutic challenge in neovascular age-related macular degeneration (AMD). Neovascular remodeling occurs after laser-induced choroidal neovascularization (CNV) in aged but not young mice. Additionally, bone marrow-derived cells, including macrophages, endothelial precursor cells, and mesenchymal precursor cells, contribute to CNV severity. In this study, we investigated the impact of aged bone marrow transplantation (BMT) on the degree of fibrosis, size, and vascular morphology of CNV lesions in a mouse model of laser-induced CNV. Young (2 months) and old (16 months) mice were transplanted with green fluorescent protein (GFP)-labeled bone marrow isolated from either young or old donors. Laser CNV was induced 1 month following transplant, and eyes were analyzed via choroidal flat mounts and immunohistochemistry 1 month postlaser. The identity of cells infiltrating CNV lesions was determined using specific markers for the labeled transplanted cells (GFP+), macrophages (F4/80+), perivascular mesenchymal-derived cells (smooth muscle actin, SMA+), and endothelial cells (CD31+). Bone marrow transplantation from aged mice transferred susceptibility to NVR into young recipients. Inversely, transplantation of young marrow into old mice prevented NVR, preserving small size and minimal fibrosis. Mice with NVR demonstrated a greater relative contribution of marrow-derived SMA+ perivascular mesenchymal cells as compared to other cells. Our findings indicate that the status of bone marrow is an important determining factor of neovascular severity. Furthermore, we find that perivascular mesenchymal cells, rather than endothelial cells, derived from aged bone marrow may contribute to increased CNV severity in this murine model of experimental neovascularization.

Aurintricarboxylic Acid Inhibits Complement Activation, Membrane Attack Complex, and Choroidal Neovascularization in a Model of Macular Degeneration

Immunocytochemical and genetic data implicate a significant role for the activation of complement in the pathology of AMD. Individuals homozygous for a Y402H polymorphism in Factor H have elevated levels of membrane attack complex (MAC) in their choroidal blood vessels and RPE relative to individuals homozygous for the wild-type allele. An R95X polymorphism in C9, a protein necessary for the final assembly of MAC, is partially protective against the formation of choroidal neovascularization (CNV) in AMD patients. Aurintricarboxylic Acid (ATA) is a small molecule inhibitor of MAC. Our hypothesis was that attenuation of the formation of MAC on ocular tissues by ATA may protect mice against laser-induced CNV. The ability of ATA to inhibit human complement-mediated cell lysis, inhibit formation of human MAC, and inhibit formation of tubes by endothelial cells was examined in vitro. Subsequently, the Bruch's membrane of adult mice was damaged using an argon laser, followed by intravitreal injection of ATA. One week later, choroidal flat mounts from these mice were stained for the presence of MAC, endothelial cells, and macrophages. ATA protects cells from human complement-mediated lysis, attenuates assembly of the MAC, and inhibits tube formation by endothelial cells in vitro. ATA also attenuates CNV, MAC deposition, and macrophage infiltration in a murine model of exudative AMD. ATA warrants further study as a potential drug for the treatment of exudative and nonexudative AMD.

Antiangiogenic effects of tivozanib, an oral VEGF receptor tyrosine kinase inhibitor, on experimental choroidal neovascularization in mice

We investigated the effects of tivozanib, an oral vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor, on experimental choroidal neovascularization (CNV) in mice. C57BL/6 mice were treated with tivozanib (1 mg/kg/day) or vehicle at the onset (day 0) of the study and experimental CNV was induced by laser photocoagulation the following day. In the other groups, tivozanib or vehicle was started 7 days after the laser photocoagulation to determine the effects of the drug on established CNV. To evaluate changes in the CNV lesions, choroidal flat mounts, fluorescein angiography, immunofluorescence staining with isolectin B4, and histological examinations were performed 14 days after CNV induction. Expression of phosphorylated ERK1/2 in choroidal tissues was measured by western blot analysis to demonstrate the inhibitory effect of tivozanib on intracellular signaling pathways involved in CNV development. Compared to vehicle-treatment, tivozanib suppressed the development of CNV lesions and led to a significant regression of established CNV, reducing the affected areas by 80.7% and 67.7%, respectively. On fluorescein angiography, tivozanib-treated mice had significantly less fluorescence leakage than vehicle-treated mice (P < 0.001). On immunofluorescence staining, the isolectin B4-labeled area was smaller in tivozanib-treated mice (P < 0.001). Phosphorylated ERK 1/2 levels increased after CNV induction by laser application and were suppressed by tivozanib treatment. Tivozanib effectively inhibited the progression of CNV in an experimental CNV model. These results suggest that tivozanib may be a therapeutic alternative for the treatment of neovascular age-related macular degeneration.

Effect of a Chinese Herbal Preparation-Mingjing Granule on the recruitment and adhesion of bone-marrow derived cells to choroidal neovascularization in mice induced by laser photocoagulation

Objective To observe the effect of Chinese Herbal Preparation-Mingjing Granule on the recruitment and adhesion of bone-marrow derived cells (BMCs) to choroidal neovascu1arization (CNV) in mice induced by laser photocoagulation.Methods A total of 75 C57BL/6 mice were divided into treatment group (30 mice),control group (30 mice) and normal control group (15 mice).CNV was induced by krypton laser in the mice of treatment group and control group.BMCs from GFP-transgenic mice were injected through tail vein to those mice 0.5-1.0 hours after laser surgery.On day one after laser surgery,the mice of treatment group were gavaged with 0.3 ml Mingjing Granule solution every day[30 g/(kg · d)],while the control group mice were gavaged with distilled water.The mice of normal group fed with normal cereals.7,14,28 days after treatment,choroidal flatmount were prepared to measure the CNV severity and BMCs recruitment.The choroidal histopathological change was observed by optical microscope.CXCR4 level in peripheral blood was measured by enzyme-linked immuno sorbent assay (ELISA).Stromal cell derived factor-1α (SDF-1α),vascular cell adhesion molecule-1 (VCAM-1),intercellular adhesion molecule 1 (ICAM-1) were detected by immunofluorescent staining.Results Choroidal flatmount showed that CNV developed in treatment group and control group,but not in normal group.On day seven and 14,CNV lesions in the treatment group showed less incorporation of BMCs and smaller CNV in size compared with the control group (t=10,9; P=0.007,0.024),histologic sections also showed less severe lesions in the treatment group.CXCR4 level in peripheral blood in the treatment group was less than that in the control group and normal control group on day seven and day 14(t=8.107,2.747; P＜0.05).The expression of SDF-1α,ICAM-1 and VCAM-1 in the treatment group was lower compared with the control group.Conclusions Mingjing Granule could inhibit the recruitment and adhesion of BMCs in peripheral blood to CNV at the early stage.The mechanism may be related with the action of Mingjing Granule in lowing chemokines levels in peripheral blood and expression of adhesion molecules around CNV. Key words: Herba ecliptae/drug effects; Astragalus membranaceus/drug effects; Choroidal neovascularization; Animal experimentation

Pathogenic Role of the Wnt Signaling Pathway Activation In Laser-Induced Choroidal Neovascularization

Choroidal neovascularization (CNV) is a severe complication of AMD. The Wnt signaling pathway has been shown to mediate angiogenesis. The purpose of this study was to investigate the pathogenic role of the Wnt pathway in CNV and explore the therapeutic potential of a novel Wnt signaling inhibitor in CNV. Adult rats and mice were photocoagulated using diode laser to induce CNV. On the same day, the animals were intravitreally injected with a monoclonal antibody (Mab2F1) blocking LRP6 or nonspecific mouse IgG. The Wnt signaling activation and target gene expression in the eyecup were determined by Western blot analysis. Fundus angiography was used to examine leakage from the laser lesion. CNV areas were measured on choroidal flatmount using FITC-dextran. Levels of Wnt pathway components and Wnt target gene expression were elevated in both laser-induced CNV rat and mouse eyecups, suggesting activation of the Wnt pathway. Significant suppression of Wnt signaling was observed in the Mab2F1 treatment group. Mab2F1 decreased vascular leakage from CNV lesions and reduced the neovascular area in laser-induced CNV rats. Mab2F1 inhibited the hypoxia-induced activation of Wnt signaling in cultured RPE cells. Mab2F1 also ameliorated retinal inflammation and vascular leakage in the eyecups of very low-density lipoprotein receptor knockout mice, a model of subretinal neovascularization. The Wnt pathway is activated in the laser-induced CNV models and plays a pathogenic role in CNV. Blockade of Wnt signaling using an anti-LRP6 antibody has therapeutic potential in CNV.

Suppression of Experimental Choroidal Neovascularization by Curcumin in Mice

PurposeTo investigate the effects of curcumin on the development of experimental choroidal neovascularization (CNV) with underlying cellular and molecular mechanisms.MethodsC57BL/6N mice were pretreated with intraperitoneal injections of curcumin daily for 3 days prior to laser-induced CNV, and the drug treatments were continued until the end of the study. The CNV area was analyzed by fluorescein-labeled dextran angiography of retinal pigment epithelium (RPE)-choroid flat mounts on day 7 and 14, and CNV leakage was evaluated by fluorescein angiography (FA) on day 14 after laser photocoagulation. The infiltration of F4/80 positive macrophages and GR-1 positive granulocytes were evaluated by immunohistochemistry on RPE-choroid flat mounts on day 3. Their expression in RPE-choroid complex was quantified by real-time PCR (F4/80) and Western blotting (GR-1) on day 3. RPE-choroid levels of vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1, and intercellular adhesion molecule (ICAM)-1 were examined by ELISA on day 3. Double immunostaining of F4/80 and VEGF was performed on cryo-sections of CNV lesions on day 3. The expression of nuclear factor (NF)-κB and hypoxia-inducible factor (HIF)−1α in the RPE-choroid was determined by Western blotting.ResultsCurcumin-treated mice had significantly less CNV area (P<0.05) and CNV leakage (P<0.001) than vehicle-treated mice. Curcumin treatment led to significant inhibition of F4/80 positive macrophages (P<0.05) and GR-1 positive granulocytes infiltration (P<0.05). VEGF mainly expressed in F4/80 positive macrophages in laser injury sites, which was suppressed by curcumin treatment (P<0.01). Curcumin inhibited the RPE-choroid levels of TNF-α (P<0.05), MCP-1 (P<0.05) and ICAM-1 (P<0.05), and suppressed the activation of NF-κB in nuclear extracts (P<0.05) and the activation of HIF−1α (P<0.05).ConclusionCurcumin treatment led to the suppression of CNV development together with inflammatory and angiogenic processes including NF-κB and HIF−1α activation, the up-regulation of inflammatory and angiogenic cytokines, and infiltrating macrophages and granulocytes. This provides molecular and cellular evidence of the validity of curcumin supplementation as a therapeutic strategy for the suppression of age-related macular degeneration (AMD)-associated CNV.

In-vivo investigation of laser-induced choroidal neovascularization in rat using spectral-domain optical coherence tomography (SD-OCT)

This study investigated the in-vivo formation process of laser-induced choroidal neovascularization (CNV) in rat using high-resolution spectral-domain optical coherence tomography (SD-OCT), and compared the results to histological methods. Brown Norway rats (n=60, 6-8 weeks of age) received 532-nm diode laser photocoagulation. SD-OCT and fluorescein angiography (FA) were performed in vivo 2, 5, 7, 14, and 21days post-laser application. Haematoxylin and eosin (H&E) staining and immunohistochemistry for CD31, phosphorylated vascular endothelial factor receptor 2 (pVEGFR2) were conducted at each time point to observe the CNV in vitro. Choroidal flatmount preparations were observed using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM). SD-OCT monitored the longitudinal morphological changes of laser-induced CNV. CNV reached its maximal size on day 7, and began a gradual reduction on day 14. FA revealed similar dynamic changes in leakage. CNV thickness, as assessed by SD-OCT, was consistent with H&E-stained sections at each time point. CLSM and SEM revealed the details of the fibrovascular membrane. CD31 and pVEGFR2 expression supported the results of SD-OCT and histology. SD-OCT was a convenient and reliable tool for the imaging of the CNV formation process and quantification of the lesion size in vivo.

Lentivirus Vector-Mediated Knockdown of Erythropoietin-Producing Hepatocellular Carcinoma Receptors B4 Inhibits Laser-Induced Choroidal Neovascularization

To evaluate the efficacy of erythropoietin-producing hepatocellular carcinoma receptors B4 (EphB4) knockdown on the development of laser-induced choroidal neovascularization (CNV) in vivo. We constructed recombinant lentiviral vectors (Lv) Lv-shRNA-EphB4 to specifically knock down the expression of EphB4. The mRNA and protein expression of EphB4 was investigated by real-time reverse transcription-polymerase chain reaction (RT-PCR) and western blot. CNV was induced by laser photocoagulation in C57BL/6 mice. The mice were then randomly assigned to be intravitreally injected with phosphate-buffered saline (PBS), Lv-shRNA-EphB4 recombinant lentivirus, or an unrelated shRNA recombinant lentivirus (pFU LV-shRNA-NC). An uninjected group was used as the control. Fundus fluorescein angiography (FFA), histologic analysis, and choroidal flat mounts analysis were applied to evaluate the inhibition of CNV after an intravitreal injection. Transfection of Lv-shRNA-EphB4 led to the knockdown of EphB4, and EphB4 mRNA was down-regulated by about 80%. FFA and histologic analysis revealed that the leakage areas and the mean thickness of CNV were much smaller in the Lv-shRNA-EphB4 group than in the PBS-treated, pFU Lv-shRNA-NC group and the non-injection group. Choroidal flat mounts showed significantly less leakage and smaller leakage areas in the Lv-shRNA-EphB4 group than those in other groups. Knocking down the expression of EphB4 exerts an inhibitory effect on CNV in vivo. It may provide a potential strategy for the treatment of CNV.

Antiangiogenic Effects of Axitinib, an Inhibitor of Vascular Endothelial Growth Factor Receptor Tyrosine Kinase, on Laser-Induced Choroidal Neovascularization in Mice

Purpose: To investigate the effects of axitinib, an inhibitor of vascular endothelial growth factor receptors, on choroidal neovascularization (CNV) in an animal model of neovascular age-related macular degeneration (AMD).Methods: Experimental CNV lesions were induced in C57BL/6 mice by laser photocoagulation. Beginning 1 day after CNV induction, mice were treated with axitinib (5 mg/kg/day) or vehicle for 2 weeks. In other groups of mice, axitinib or vehicle treatment was started 7 days after the laser application to determine the effect of the drug on established CNV. Untreated mice were used as a baseline group. Two weeks after laser injury, the extent of CNV was assessed from choroidal flat mounts perfused with fluorescein-labeled dextran. Immunofluorescence staining with isolectin IB4 was also used to quantify the CNV lesions.Results: Orally administered axitinib inhibited CNV growth in the laser-induced CNV model. Axitinib caused a 70.1% inhibition of CNV lesions compared to vehicle-treatment (p < 0.001). Axitinib also caused a significant regression of established CNV, reducing the area by 71.1% compared to vehicle treatment (p < 0.001). Moreover, immunofluorescence staining showed that the area of isolectin IB4 labeled vessels was smaller in the axitinib-treated group compared to the vehicle-treated group (p < 0.001).Conclusions: Axitinib effectively inhibits the progression of CNV in an experimental animal model. These results suggest that axitinib could constitute a therapeutic alternative for the treatment of neovascular AMD.

Effect of Resvega in a model of choroidal neovascularization in mice

AbstractPurpose We aim to assess the effect of Resvega as a source of resveratrol and combined with an anti‐VEGF in a diode laser‐induced choroidal neovascularization (Li‐CNV) model in mice.Methods Sixty C57BL6/J mice underwent a diode Li‐CNV model, and were divided into 4 groups (n=15): Control group: vehicle by oral gavage. NA group: daily oral Resvega (NA). C‐VEGF group: vehicle and intravitreal anti‐VEGF. NA‐VEGF group: NA and intravitreal anti‐VEGF. Oral treatments (100 µL) were administered 10 days before laser until 28 days post‐laser. Intravitreal injections (7 µl) were performed 48 hours after laser. CNV evolution was assessed weekly through fluorescein angiography (FA) for 4 weeks. CD‐31 immunofluorescence was assessed in choroidal flat mounts after sacrifice. Gene and protein expression of VEGF was analyzed with RT‐PCR and western‐blot, respectively. Results were analyzed with SPSS 15.0.Results FA showed a significant decrease in fluorescein leakage from second week in NA and NA‐VEGF groups compared with their respective controls (p&lt;0.05). The lowest CNV area measured by CD31 was observed in NA group compared with control group with statistically significant differences (p&lt;0.05). RT‐PCR and western‐blot analysis showed a significant decrease in VEGF expression in NA and NA‐VEGF groups (p&lt;0.05).Conclusion Our data show that oral Resvega administration reduces CNV area and expression of proangiogenic VEGF expression. These results suggest that Resvega could be considered as potential preventive therapy against CNV. Supported in part by Thea Laboratoires and Grant RETICS RD 07/0062, Ministerio de Ciencia e Innovación.

Effect of cediranib, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, in a mouse model of choroidal neovascularization

This study was conducted to evaluate the effect of cediranib, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, in a mouse model of laser-induced choroidal neovascularization. Choroidal neovascularization was induced in C57BL/6 mice by rupturing Bruch's membrane using laser photocoagulation. Following laser injury, the mice were divided into three groups and administered either vehicle, 1 mg/kg or 5 mg/kg of cediranib daily by oral gavage for 2 weeks. Two weeks after laser injury, the area of choroidal neovascularization lesions was measured by choroidal flat mounts using fluorescein-labelled dextran. Immunofluorescence staining with isolectin IB4 was also used to quantify the choroidal neovascularization lesions. Choroidal flat mount analysis revealed that orally administered cediranib reduced the extent of choroidal neovascularization. The groups treated with 1 and 5 mg/kg/day showed 57.2 and 66.0% reduction of choroidal neovascularization lesions, respectively, compared with the control group treated with vehicle alone (P = 0.012). The size of the fluorescently labelled choroidal neovascularization complex in cediranib-treated groups was much smaller than that from vehicle-treated group (P = 0.035). Cediranib inhibited laser-induced choroidal neovascularization in mice and may have therapeutic potential for patients with neovascular age-related macular degeneration.

Lack of Thrombospondin 1 and Exacerbation of Choroidal Neovascularization

To assess the impact of thrombospondin 1(TSP1) deficiency on choroidal neovascularization (CNV)and to determine whether administration of a TSP1 antiangiogenic mimetic peptide attenuates CNV. The impact of TSP1 deficiency on laser induced CNV was assessed using wild-type (TSP1 +/+) and TSP1-deficient (TSP1 −/−) mice. Three laser burns were placed in each eye of TSP1 +/+ and TSP1 −/− mice to induce CNV. Intravitreal injection of the TSP1 mimetic peptide was performed on days 1 and 7 postlaser in the mice.For quantitative measurements of neovascularization, intercellular adhesion molecule 2 staining was performed at 14 days postlaser of the choroidal-sclera flat mounts. The recruitment of macrophages to the sites of damage was investigated by immunohistochemistry. The CNV area was measured by intercellular adhesion molecule 2 staining and use of ImageJ software. The TSP1 −/− mice exhibited significantly larger areas of neovascularization on choroidal flat mounts compared with TSP1 +/ mice. This was consistent with enhanced recruitment of macrophages in TSP1 −/− mice compared with TSP1 +/+ mice 3 days postlaser. The development of CNV was significantly attenuated in mice receiving the TSP1 antiangiogenic mimetic peptide compared with those receiving vehicle alone. Deficiency of TSP1 contributes to enhanced choroidal neovascularization. This is consistent with the anti-inflammatory and antiangiogenic activity of TSP1. The TSP1 antiangiogenic peptide was effective in attenuation of CNV. Intravitreal injection of TSP1 antiangiogenic mimetic peptides may provide alternative treatment for CNV.

Macrophage activation associated with chronic murine cytomegalovirus infection results in more severe experimental choroidal neovascularization.

The neovascular (wet) form of age-related macular degeneration (AMD) leads to vision loss due to choroidal neovascularization (CNV). Since macrophages are important in CNV development, and cytomegalovirus (CMV)-specific IgG serum titers in patients with wet AMD are elevated, we hypothesized that chronic CMV infection contributes to wet AMD, possibly by pro-angiogenic macrophage activation. This hypothesis was tested using an established mouse model of experimental CNV. At 6 days, 6 weeks, or 12 weeks after infection with murine CMV (MCMV), laser-induced CNV was performed, and CNV severity was determined 4 weeks later by analysis of choroidal flatmounts. Although all MCMV-infected mice exhibited more severe CNV when compared with control mice, the most severe CNV developed in mice with chronic infection, a time when MCMV-specific gene sequences could not be detected within choroidal tissues. Splenic macrophages collected from mice with chronic MCMV infection, however, expressed significantly greater levels of TNF-α, COX-2, MMP-9, and, most significantly, VEGF transcripts by quantitative RT-PCR assay when compared to splenic macrophages from control mice. Direct MCMV infection of monolayers of IC-21 mouse macrophages confirmed significant stimulation of VEGF mRNA and VEGF protein as determined by quantitative RT-PCR assay, ELISA, and immunostaining. Stimulation of VEGF production in vivo and in vitro was sensitive to the antiviral ganciclovir. These studies suggest that chronic CMV infection may serve as a heretofore unrecognized risk factor in the pathogenesis of wet AMD. One mechanism by which chronic CMV infection might promote increased CNV severity is via stimulation of macrophages to make pro-angiogenic factors (VEGF), an outcome that requires active virus replication.

Suppression and regression of choroidal neovascularization in mice by a novel CCR2 antagonist, INCB3344.

PurposeTo investigate the effect of an intravitreally administered CCR2 antagonist, INCB3344, on a mouse model of choroidal neovascularization (CNV).MethodsCNV was induced by laser photocoagulation on Day 0 in wild type mice. INCB3344 or vehicle was administered intravitreally immediately after laser application. On Day 14, CNV areas were measured on retinal pigment epithelium (RPE)-choroid flat mounts and histopathologic examination was performed on 7 µm-thick sections. Macrophage infiltration was evaluated by immunohistochemistry on RPE-choroid flat mounts and quantified by flow cytometry on Day 3. Expression of vascular endothelial growth factor (VEGF) protein in RPE-choroid tissue was examined by immunohistochemistry and ELISA, VEGF mRNA in sorted macrophages in RPE-choroid tissue was examine by real-time PCR and expression of phosphorylated extracellular signal-regulated kinase (p-ERK 1/2) in RPE-choroid tissue was measured by Western blot analysis on Day 3. We also evaluated the efficacy of intravitreal INCB3344 to spontaneous CNV detected in Cu, Zn-superoxide dismutase (SOD1) deficient mice. Changes in CNV size were assessed between pre- and 1week post-INCB3344 or vehicle administration in fundus photography and fluorescence angiography (FA).ResultsThe mean CNV area in INCB3344-treated mice decreased by 42.4% compared with the vehicle-treated control mice (p<0.001). INCB3344 treatment significantly inhibited macrophage infiltration into the laser-irradiated area (p<0.001), and suppressed the expression of VEGF protein (p = 0.012), VEGF mRNA in infiltrating macrophages (p<0.001) and the phosphorylation of ERK1/2 (p<0.001). The area of spontaneous CNV in Sod1 −/− mice regressed by 70.35% in INCB3344-treated animals while no change was detected in vehicle-treated control mice (p<0.001).ConclusionsINCB3344 both inhibits newly forming CNV and regresses established CNV. Controlling inflammation by suppressing macrophage infiltration and angiogenic ability via the CCR-2/MCP-1 signal may be a useful therapeutic strategy for treating CNV associated with age-related macular degeneration.

Gene transfer using micellar nanovectors inhibits choroidal neovascularization in vivo.

PurposeAge-related macular degeneration caused by choroidal neovascularization (CNV) remains difficult to be treated despite the recent advent of several treatment options. In this study, we investigated the in vivo angiogenic control by intravenous injection of polyion complex (PIC) micelle encapsulating plasmid DNA (pDNA) using a mice CNV model.MethodsThe transfection efficiency of the PIC micelle was investigated using the laser-induced CNV in eight-week-old male C57 BJ/6 mice. Firstly, each mouse received intravenous injection of micelle encapsulating pDNA of Yellow Fluorescent Protein (pYFP) on days 1,3 and 5. The expression of YFP was analyzed using fluorescein microscopy and western blotting analysis. In the next experiments, each mouse received intravenous injection of micelle encapsulating pDNA of soluble Fms-like tyrosine kinase-1 (psFlt-1) 1,3 and 5 days after the induction of CNV and the CNV lesion was analyzed by choroidal flatmounts on day 7.ResultsFluorescein microscopy and western blotting analysis revealed that the expression of YFP was confirmed in the CNV area after injection of the PIC micelle, but the expression was not detected neither in mice that received naked pDNA nor those without CNV. Furthermore, the CNV area in the mice that received intravenous injection of the psFlt-1-encapsulated PIC micelle was significantly reduced by 65% compared to that in control mice (p<0.01).ConclusionsTransfection of sFlt-1 with the PIC micelle by intravenous injection to mice CNV models showed significant inhibition of CNV. The current results revealed the significant potential of nonviral gene therapy for regulation of CNV using the PIC micelle encapsulating pDNA.

The Antiangiogenic Effects of Integrin α5β1 Inhibitor (ATN-161) In Vitro and In Vivo

Integrin α5β1 is involved in the development of choroidal neovascularization (CNV). Thus, the inhibition of integrin α5β1 may provide an alternative to the current standard of CNV therapy, which involves inhibition of vascular endothelial growth factor (VEGF) and is not effective in all patients. This study evaluated the antiangiogenic effects of ATN-161, a small peptide inhibitor of integrin α5β1, in human choroidal endothelial cells (hCECs) and in laser-induced CNV in rats. Furthermore, the utility of spectral-domain optical coherence tomography (SD-OCT) for dynamic observation of the development of CNV in animal models was assessed. The antiangiogenic potential of ATN-161 was evaluated in VEFG-stimulated hCECs by MTS proliferation assays, migration assays, and synthetic matrix capillary tube formation assays. To evaluate the antiangiogenic effects of ATN-161 in vivo, CNV was induced in rats by laser photocoagulation. ATN-161, scrambled peptide, or AF564 anti-VEGF antibody, were injected intravitreally immediately after photocoagulation. Eyes were examined by SD-OCT and fluorescein angiography on days 1, 7, and 14 after injection, and the areas of CNV were measured by analysis of choroidal flatmounts at day 14. ATN-161 inhibited VEGF-induced migration and capillary tube formation in hCECs, but did not inhibit proliferation. In vivo, injection of ATN-161 after laser photocoagulation inhibited CNV leakage and neovascularization to an extent similar to AF564. Furthermore, SD-OCT and histologic examinations indicated that ATN-161 significantly decreased the size of laser-induced lesions. Integrin α5β1 inhibition by ATN-161 may be a promising alternative therapy for CNV-related angiogenesis. In addition, SD-OCT technology allows excellent visualization of experimentally induced CNV in vivo.

Recruitment of Blood-Derived Inflammatory Cells Mediated via Tumor Necrosis Factor-α Receptor 1b Exacerbates Choroidal Neovascularization

Purpose. Tumor necrosis factor (TNF)-α contributes to inflammation-associated angiogenesis, and TNF-α receptor 1b is selectively expressed on immuno-competent and endothelial cells. This study investigated the role of TNF-α receptor 1b in the recruitment of circulating inflammatory cells and the development of choroidal neovascularization (CNV). Methods. Lethally irradiated Tnfrsf1b(-/-) mice and their wild-type (WT) controls were transplanted with whole adult bone marrow (BM) cells, competent for both TNF-α receptors 1a and 1b (gfp(+) labeled), as well as with BM cells deficient for TNF-α receptor 1b. One month after transplantation CNV was induced by laser damage of Bruch's membrane. Pathologic angiogenesis was estimated qualitatively and quantitatively by histology on choroidal flatmounts and paraffin cross sections. Macrophage invasion was investigated by immunochemistry. Results. One month after transplantation the reconstitution rate measured by FACS analysis was >80% in gfp(+)-chimeric mice. Two weeks after laser injury reduced gfp(+)-cell invasion to the laser scars and decreased pathologic angiogenesis were observed in Tnfrsf1b(-/-) versus WT recipients. Approximately 70% of the invaded gfp(+) cells were labeled with macrophage marker F4/80. Transplantation of TNF-α receptor 1b-deficient BM cells in WT recipients reduced the CNV lesion compared with WT and Tnfrsf1b(-/-) recipients that received TNF-α receptor-competent BM cells. Transplantation of receptor 1b-deficient cells to Tnfrsf1b(-/-) recipients further reduced the degree of CNV formation. Conclusions. Signals through TNF-α receptor 1b expressed on BM -derived inflammatory cells mediate an increased inflammatory cell invasion and enhanced angiogenic response after laser-induced rupture of Bruch's membrane.

Establishment of a New Animal Model of Focal Subretinal Fibrosis That Resembles Disciform Lesion in Advanced Age-Related Macular Degeneration

Subretinal fibrosis causes damage to visual acuity, especially if the lesion is in the macula, as is frequently observed in advanced age-related macular degeneration. Exudate leukocytes form abnormal vessels that initiate regional inflammation accompanied with local glial proliferation and matrix production. The purpose of this study was to establish an animal model of focal subretinal fibrosis. Macrophage-rich peritoneal exudate cells (PECs) were injected into the subretinal space of C57BL/6 or MCP-1 knockout (KO) mice. Seven days later, the size of the subretinal fibrotic tissue was evaluated by the adherent area of glial fibrillary acidic protein (GFAP)-positive retinal glial cells on choroidal flat mounts. Myofibroblastic changes and collagen synthesis were detected by α-smooth muscle actin (α-SMA) and Masson trichrome staining of the histologic section, respectively. α-SMA expression was also examined on retinal pigment epithelium (RPE) cells during co-culture with activated macrophages. Subretinal fibrous tissue was observed by funduscopy in PEC-injected mice after 7 days. The tissue consisted of a monotonous, low-cell-density area that expressed α-SMA with collagen synthesis. Both steroid and antioxidant treatment can reduce residual glia. Because PEC-injected MCP-1 KO mice showed less residual glia, not only exogenous macrophages, but also intrinsic macrophages were activated. The macrophages directly induced myofibrotic changes in RPE cells in vitro. Activated macrophages form subretinal fibrosis when they are placed in the subretinal space and induce myofibrotic changes in RPE cells.

Monocyte/macrophages promote vasculogenesis in choroidal neovascularization in mice by stimulating SDF-1 expression in RPE cells

Monocyte-macrophages play important roles in choroidal neovascularization (CNV); however, the mechanism is unclear. This study investigated the effects of monocyte depletion on laser-induced CNV in mice, especially the involvement of bone marrow-derived cells (BMCs) and underlying molecular mechanisms. Clodronate-liposomes (lip) were used to deplete monocytes and their effect on retinal pigmental epithelium (RPE) cells, endothelial cells, and BMCs was analyzed. Green fluorescent protein (GFP)-chimeric mice were developed by transplanting bone marrow cells from GFP transgenic mice to C57BL/6J mice. CNV was induced by laser photocoagulation. Chimeric mice were intravenously treated with clodronate-lip, PBS-lip or PBS, 1day before and after lasering. Histopathological and choroidal flatmount analysis were performed to measure CNV severity and BMCs recruitment. BMCs expression of endothelial cell marker CD31 and vascular smooth muscle cell marker α-SMA in CNV were detected by immunofluorescence. Expression of stromal cell-derived factor-1 (SDF-1) protein in vivo was detected by immunofluorescence as well as ELISA assay. SDF-1 was also examined by RT-PCR and ELISA in a human monocytes-RPE cells co-culturing system. No valid evidence for the toxicity of clodronate-lip was found. Depletion led to significant inhibition of CNV and BMCs recruitment into laser spots on days 3 and 14, reduced BMC expression of CD31 and α-SMA on day 14, and decreased expression of SDF-1 in vivo on day 3. SDF-1 was mostly within and around the RPE cells in the laser lesion. SDF-1 was dramatically up-regulated in RPE cells after co-culturing with monocytes. Monocytes may promote experimental CNV, especially BMC contribution in mice, by promoting SDF-1 production in RPE cells.