Axon guidance molecules, slit glycoprotein (Slit) and Roundabout receptors (Robo) were firstly identified in the central neural system of Drosophila melanogaster. The Slit-Robo signal plays a crucial role in axon guidance, inflammation, tumor metastasis and angiogenesis, of which the role of Slit2-Robo pathway in angiogenesis has drawn a greater attention and still remains conflicting. Herein, we provide a review on the role of Slit2-Robo pathway in ocular angiogenesis and vascularization of other organs and systems. We hope this review will be the basis of further study on the mechanism of Slit2-Robo signaling on angiogenesis and provide new target for the therapy on ocular vascular disease
ObjectiveTo study the inhibitory effects of pigment epithelium derived factor (PEDF) on oxygen-induced retinal neovascularization in mice, and to investigate the possible involvement of interleukin-1β (IL-1β) in the neovascular-inhibitory function of PEDF. Methods A total of 140 postnatal day (P)7 C57BL/6 mice were randomly divided into normal control group, oxygen-induced retinopathy (OIR) model group, PEDF treatment group and PBS treatment control group. All mice except normal control group with their mothers were exposed to (75±2)% oxygen environment for 5 days and then kept in room air for another 5 days to establish the OIR model. Mice in normal control group were kept in room air only. At P12 and P14, respectively, mice in PEDF treatment group received intravitreous injections of 1 μl PEDF (2 μg/μl), while PBS treatment control group received the same volume of PBS (10 mmol/L, pH7.4).All mice were euthanized at P17 and eyes were isolated. The changes of retinal vessels were observed on retinal flat mounts and cryosections by fluorescence microscopy. Retinal specimens were prepared for IL-1β protein and mRNA analysis by Western blot and real time fluorescence quantitative reverse transcription-polymerase chain reaction (Real-time RT-PCR). ResultsChanges of retinal vessels had been viewed by fluorescence microscopy on flat-mounted retina, the relative retinal neovascularization areas were significantly increased in OIR model group compared with normal control group (t=15.02, P < 0.01), and the relative retinal neovascularization areas were obviously smaller in PEDF treatment group than those in PBS treatment control group (t=5.96, P < 0.01). Fluorescence staining revealed that retinal vascular tufts were extending from outer plexiform layer (OPL) to ganglion cell layer (GCL) of the retina along with multiple interconnections; Neovascular tufts in OIR model group and PBS treatment control group were presenting distinctly more than those of normal control group and PEDF treatment group. The specific expression levels of IL-1β protein in retinas of OIR mice by Western-blot analysis were higher than those of normal control group(t=3.35, P < 0.05), While these of PEDF treatment group showed a considerable decline in comparison with PBS treatment control group (P < 0.01), and there were no difference in normal control group and PEDF-treated group (F=11.764, P > 0.05). Similarly, expression levels of IL-1β mRNA tested by Real-time RT-PCR were obviously increased in the OIR model group when compared to normal control group(t=4.43, P < 0.01). After treated with PEDF, expression levels of IL-1β mRNA showed a considerable decrease when compared to PBS treatment control group (P < 0.01), and there were no difference in normal control group and PEDF-treated group (F=11.15, P > 0.05). ConclusionsPEDF can inhibit oxygen-induced retinal neovascularization. The mechanism may be related to that PEDF can downregulate the expression of IL-1β in retina.
Objective To compare the features of OCT angiography (OCTA) between neovascular age-related macular degeneration (nAMD) and myopic choroidal neovascularization (mCNV) patients before and after intravitreal anti-VEGF treatment. Methods A prospective cohort study. Twenty-nine patients (37 eyes) with nAMD (19 males and 10 females, aged 68.20±8.76) and 31 patients (34 eyes) with mCNV (9 males and 22 females, aged 43.10±11.80, with the mean diopter of −9.71±1.20 D) from Department of Ophthalmology, West China Hospital of Sichuan University during May and December 2017 were included in this study. Ranibizumab or Conbercept (0.5 mg/0.05 ml) was intravitreally injected in all eyes. The patients were follow-up for 3−6 months. The OCTA was conducted before treatment and 1 day, 1 week, 1 month and 3−6 months after treatment. In order to ensure that the scanning position was the same, the tracking mode was adopted for each scanning. According to the OCTA images, the lesion area, parafoveal superficial vessel density and perfusion area were measured and analyzed contrastively between nAMD and mCNV patients. Results The mean lesion area before and 1 month after treatment in nAMD patients were 0.38±1.87 mm2 and 0.06±0.12 mm2, while in mCNV patients, those were 0.26±1.06 mm2 and 0.03±0.05 mm2, respectively. There were statistically significant differences (Z=4.181, 4.475; P＜0.001) in CNV lesion area before and 1 month after treatment between nAMD and mCNV patients. Compared with those before treatment, the absolute change (Z=1.853, P=0.064) and the percentage changes (t=2.685, P=0.010) of CNV lesion area 1 month after treatment in nAMD and mCNV patients show a statistical meaning. There were significantly decreases in both parafoveal superficial vessel density (F=8.997, P=0.003) and perfusion area (F=7.887, P=0.015) 3 months after treatment in nAMD patients, while decreases in parafoveal superficial vessel density (F=11.142, P=0.004) and perfusion area (F=7.662, P=0.013) could be detected 1 day after treatment in mCNV patients, before rising 1 month after treatment. Conclusions There are significantly differences in lesion area before and after the treatment of intravitreal anti-VEGF between nAMD and mCNV patients by OCTA examination. Moreover, the changes of both parafoveal superficial vessel density and perfusion area after anti-VEGF treatment are statistically different in two groups.
Interleukin-18 is an inactive precursor which lacks a signal peptide, it has a role in regulating retinal pathological angiogenesis. It also inhibits experimental choroidal neovascularization (CNV) via interferon-γand thrombospondin-1. Currently little is known about its mechanisms of inhibition for CNV, may be speculated to be due to effects of anti-angiogenesis, down-regulates vascular permeability and lower vascular endothelial growth factor (VEGF) levels via directly acting on the vascular endothelial cell and epithelial cells. Exogenous administration of mature recombinant interleukin-18 has no adverse effect on retinal pigment epithelial cell viability. In addition, the anti-VEGF role of interleukin-18 is tested to be safe and effective for humans. Interleukin-18 alone or in combination with anti-VEGF shows to be a good prospect for improving the prognosis of experimental CNV. However, more large clinical studies are required to confirm the exact efficacy of interleukin-18 for CNV.
Objective To observe the preventive and therapeutic effect of different times, spot reactions and spot density of argon laser photocoagulation on retinal neovas cularization of ischemic retinal vein occlusion (IRVO).Meth9al of 244 patients (268 eyes) with IRVO diagnosed by fundus fluorescein angiography (FFA) were treated by HGM argon laser photocoagulator with green-blue light with 200~500 μm lightspot, 0.1~0.5 s, 0.3~1.0 w, and II~III class spot reaction . All capillary nonperfusion areas (CNA) were photocoagulated, and so were the retinal neovascularization in some patients. The follow up periods were from 6 to 60 months. After 3 and 24 weeks after photocoagulation FFA was performed again. Photocoagulation was performed supplementarilly for the new CNA or incompletely photocoagulated areas. Ophthalmoscopic examination and FFA were performed in all the patients after half a year.Results Only 17 eyes (10.6%) with neovascularization were found after preventive photocoagulation in 160 eyes in non-neovacularization group. Sixty-nine eyes(63.9%) with neovascular atrophy and 39 eyes (36 .1%) with unsuccessful photocoagulation were found after therapeutic photocoagulation in 108 eyes in neovascularization group. There was statistical significance between the two groups (P＜0.01). Photocoagulation energy with reaction of III class and density of 1 lightspot diameter was more effective than which with reaction of II~III class and density of 1.5 lightspot diameter or reaction of ≤II class and density of 2 lightspot diameter (P＜0.01). Conclusion Efficacy of preventive photocoagulation is better than which of therapeutic photocoagulation. Photocoagulation energy with reaction of III class and density of 1 lightspot diameter is an effective method for IRVO.(Chin J Ocul Fundus Dis，2003，19：201-268)
Objective To observe the inhibitory effect of kallikrein-binding protein (KBP) on choroidal neovascularization. Methods Forty Brown Norway rats were randomly divided into the KBP groups and the control group, 20 rats in each group, the right eye as the experimental eye. The rats were photocoagulated by 532 nm laser to induce CNV model. One week after laser photocoagulation, the rats were received FFA examination. At the second day after FFA examination, the rats of KBP group were received an intravitreal injection of KBP 5 mu;l (4 mg/ml KBP). The same volume of deionized water was injected into the rats in the control group. The rats of two groups received FFA examination at one, two and three weeks after injection. The expressions of vascular endothelial growth factor and pigment epithelium derived factor were observed using hematoxylin and eosin stain and immunohistochemistry stain. CNV leakage area and the cumulative absorbance of laser spot area were analyzed by Image-Pro plus 6.0 software. Results FFA examination showed that there were CNV and fluorescence leakage at one week after laser photocoagulation; one, two and three weeks after injection, the leakage decreased gradually in KBP group, but increased with time in control group. Compared with control group, the spot area and CNV in KBP group reduced gradually, but CNV was always there in control group. The differences of VEGF (F=1.29) and PEDF (F=6.29) expressions at one week after laser photocoagulation were not statistically significant (P＞0.05). The differences of VEGF and PEDF expressions at one, two and three weeks after injection were statistically significant（VEGF:F=14.16,66.89,24.34; PEDF：F=4.22,62.04,233.05;P＜0.001）.Conclusion Intravitreal injection with KBP can inhibit CNV.
Purpose To determine the effect of exogenous interleukin-1alpha; (IL-1alpha;) on the retina and its vasculature and VEGF expression in SD rats． Methods IL-1alpha;2．0 ng (20 mu;l) were injected into the vitreous of 8 left eyes of 8 SD rats while steriled PBS were injected into 8 right contralateral eyes of the same rats as control． All eyes were assessed by direct ophthalmoscopy every day and enucleated on the 7 thpostoperative day． Histological examination (hemato xylineosin staining) and immunohistochemical staining with antibody against VEGF antigen were performed， and sections were observed and photographed under light microscopy． Results ①All 8 IL-1alpha; inject ed eyes developed epiretinal membranes and extraretinal neovascularization on the 3 rd postoperative days while none of the 8 control eyes exhibited any a bnormal retinal vascular changes and they were confirmed by HE staining;②Immuno staining identified VEGF express mainly in the inner layer of vessel walls， the epiretinal membranes， the neuroganglional layer and the photoreceptor layer of retina， while the control eyes showed only weak positive staining in the photo receptor layer． Conclusions IL-1alpha; is capable of inducing vitreo retinal neovascularization，and increasing the expression of VEGF in the retina and epiretinal membranes． (Chin J Ocul Fundus Dis, 2001,17:135-137)
ObjectiveTo investigate the risk factors for neovascular glaucoma (NVG) after vitrectomy in proliferative diabetic retinopathy (PDR) patients. MethodsThree hundred and one patients (301 eyes) with PDR who underwent vitrectomy between January 2008 and December 2013 in our hospital were retrospectively evaluated. Risk factors for NVG after vitrectomy were identified by multivariate Logistic regression analysis. ResultsTwelve of 301 patients (4.0%) developed postoperative NVG in 2 to 18 months after vitrectomy. The incidence of postoperative NVG peaked in 2 to 6 months after vitrectomy (7 eyes, 58.3%). Logistic regression analysis showed that postoperative retinal detachment was a significant risk factor for postoperative NVG in eyes with PDR (P < 0.001). Eyes with postoperative retinal detachment were more likely to develop NVG after vitrectomy than those without postoperative retinal detachment (OR=17.826). Gender, age, duration of diabetes, preoperative serum creatinine levels, glycated hemoglobin levels, preoperative intraocular pressure, preoperative lens status, combined phacoemulsification surgery and tamponade were not associated with postoperative NVG (P > 0.05). ConclusionPostoperative retinal detachment is a major risk factor for NVG after vitrectomy in PDR.