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PubMedDate not supplied

Experimental retinopathy of prematurity: angiostatic inhibition by nimodipine, ginkgo-biloba, and dipyridamole, and response to different growth factors.

PURPOSE: To investigate whether commonly used vasodilating drugs ameliorate angiogenesis in experimental retinopathy of prematurity (ROP), and to study the response of these drugs to different growth factors. METHODS: We used a rat and mouse model of oxygen-induced ischemic retinopathy. Animals were treated with nimodipine, gingko-biloba and dipyridamole intraperitoneally starting the day before exposure to room air (day 1). Controls were injected with vehicle solution only. Eyes were processed histopathologically with serial sections and neovascularization was measured by counting the nuclei within the retinal internal limiting membrane, by a masked observer. Retinal and vitreous tissues were assayed by ELISA for VEGF, PDGF and TGFbeta2. RESULTS: Nimodipine significantly inhibited the growth of new vessels in rats. The number of nuclei was 310 +/- 69 in the control group (n:14) and 121 +/- 53 in the treated ones (n:14), (p<0.0005). Similar results were found with ginkgo-biloba extracts: 344 +/- 53 (n:15) in controls, and 136 +/- 29 (n:11) in treated ones (p<0.0005), and with dipyridamole: 303 +/- 69 (n:13) in controls, and 131 +/- 48.5 in treated rats (p<0.0005). Results were similar in mice. 186 +/- 45 (n:7) nuclei counted in controls against 90 +/- 25 (n:6) for dipyridamole treated (p<0.0005); and 81 +/- 21 for ginkgo-biloba treated animals (p<0.0005). A gradual, very significant increase in VEGF values in response to relative hypoxia (room air) contrasted with the significant inhibition noted both with ginkgo-biloba extracts and dipyridamole. TGFbeta2 and PDGF both showed a gradual increase in relative hypoxia at days 2 and 4 of room air (p<0.0005). Treated animals showed marked inhibition of the three growth factors. CONCLUSIONS: All three drugs markedly inhibited angiogenesis in experimental ROP. Growth factors were elevated in hypoxic conditions. Treated animals showed significant decreases of PDGF, VEGF, and TGFbeta2 in retinal and vitreous tissues.

Animals↗
PubMedDate not supplied

Combined surgical ablation and intravitreal triamcinolone acetonide for retinal angiomatous proliferation.

PURPOSE: Neovascular age-related macular degeneration (ARMD) with retinal angiomatous proliferation (RAP) has a poor natural history and the efficacy of any treatment has not yet been established. The authors describe a combined surgical treatment. METHODS: A 76-year-old woman presented with a best-corrected visual acuity (BCVA) of 20/600 in the right eye and macula with stage 3 RAP as identified by fluorescein angiography (FA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT). After a standard three-port pars plana core vitrectomy (PPV), endodiathermy of the arteriolar and venous feeder vessels of each lesion was performed, intraretinal RAP feeder vessels were cut with manual vertical intraocular scissors, and 0.1 mL of triamcinolone acetonide (TAAC) was injected intravitreally. At 1 and 4 weeks and at the sixth month, the patient underwent a complete eye examination, FA, ICGA, and OCT to assess outcomes and complications. RESULTS: Six months later, BCVA was stable at 20/300, intraocular pressure was 15 mmHg, anterior segment and vitreous cavity were clear without evidence of TAAC granules, and retina was attached. FA and ICGA showed a complete occlusion of the RAP and absence of leakage or ischemia and OCT demonstrated decreased macular thickness with resolution of both intraretinal edema and pigment epithelium detachment, and the restoration of the normal macular profile. At the end of follow-up, the authors did not observe any ocular or systemic complication. CONCLUSIONS: Surgical approach to RAP stage 3 with intravitreal injection of 4 mg of TAAC was safe and anatomically effective.

Aged↗
PubMed1991

Neovascular response in ischaemic central retinal vein occlusion after panretinal photocoagulation.

Twenty seven eyes treated for ischaemic central retinal vein occlusion with panretinal photocoagulation were reviewed. Prior to laser therapy anterior segment neovascularisation predominated (17 eyes) over posterior segment involvement (6 eyes). After photocoagulation anterior segment new vessels regressed or did not develop in the majority of cases. However, in five eyes previously absent posterior segment neovascularisation occurred. These results suggest that photocoagulation alters but does not eliminate retinal ischemia, thus modulating the neovascular response.

Aged↗
PubMed1993

Neovascular complications after central retinal vein occlusion.

An 8-year retrospective study of patients suffering a central retinal vein occlusion (CRVO) was undertaken to study secondary new vessel formation and whether pathologies known to predispose to CRVO influenced the occurrence of these neovascular complications and their responsiveness to treatment. Seventy-three patients were studied. Ocular neovascularisation had occurred in 60%. More specifically 39% developed neovascular glaucoma. Panretinal photocoagulation produced regression in only 37% of those with established neovascularisation and was unsuccessful in preventing neovascularisation in five patients treated prophylactically. Patients with pre-existing primary open angle glaucoma (POAG) were statistically more likely to develop ocular neovascularisation (p = 0.02), which was also less responsive to laser therapy (p = 0.02). Adequate prior glaucoma therapy did not protect against this enhanced complication rate. It was concluded that POAG is a significant risk factor for developing ocular neovascularisation after CRVO which will be refractory to laser therapy.

Adult↗
PubMed1997

Vascular endothelial growth factor is present in glial cells of the retina and optic nerve of human subjects with nonproliferative diabetic retinopathy.

PURPOSE: To determine whether vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), which have been implicated in the development of retinal and choroidal neovascularization, are present in the retinas and optic nerves of patients with diabetes before proliferative retinopathy appears. METHODS: Light microscopic immunocytochemistry using antibodies to VEGF, bFGF, vimentin, glial fibrillary acidic protein (GFAP), and factor VIII on frozen sections from eyes of patients with diabetes without proliferative retinopathy, eyes of patients without diabetes and without known ocular disease, and eyes with disciform age-related macular degeneration (ARMD). Retinal vascular digest preparations to evaluate microvascular abnormalities. RESULTS: Based on morphology and on GFAP and vimentin immunopositivity, retinas from all subjects with diabetes immunostained strongly to VEGF in elongated processes that appeared to be Müller cells. Glial cells within septa surrounding axons in the anterior optic nerve also immunostained for VEGF, as did endothelial cells of some posterior retinal blood vessels and some retinal pigment epithelial cells. Retinas from eyes with disciform ARMD immunostained for VEGF, though less extensively than did those of subjects with diabetes. Retinas and optic nerves from subjects without ocular disease were VEGF negative. Basic fibroblast growth factor was expressed minimally in the inner retinal layers of subjects with and without diabetes, but it was substantial in the photoreceptor layer of all eyes. Vascular endothelial growth factor immunopositivity was present in eyes with no, or little, retinal vascular anatomic abnormality in digest preparations. CONCLUSIONS: Vascular endothelial growth factor expression precedes retinal neovascularization in the retinas and the optic nerves of humans with diabetes. Its localization to glial cells of the inner retina and the anterior optic nerve suggests a relationship to neovascularization in these sites. That VEGF immunopositivity may occur when there is no anatomic evidence of retinal nonperfusion and little likelihood of retinal neovascularization suggests the possibility that ischemia may not be the sole stimulus for VEGF expression.

Aged↗
PubMed1998

Do intraocular angiotensin II levels, plasma prothrombotic factors and endothelial dysfunction contribute to proliferative diabetic retinopathy?

PURPOSE: To investigate whether diabetic retinopathy (DR) is associated with abnormalities in: (i) aqueous humour Angiotensin I (Ang I) and Angiotensin II (Ang II) levels; and (ii) plasma Ang I, soluble P-selectin, lipoprotein (a) (Lp(a)), endothelial markers and haemorheological abnormalities. METHODS: Cross-sectional study of diabetic patients and healthy controls undergoing cataract surgery. RESULTS: 21 diabetic patients (12 males; mean age 67.0 years) were studied. Plasma levels of Ang II were lower in diabetics compared with controls (p<0.05). There were no differences in mean aqueous Ang I and Ang II levels in diabetics with or without proliferative DR compared with controls. Mean systolic blood pressure was higher in Group 1 patients (p=0.02). Patients with DR also demonstrated high Lp (a) and abnormal haemorheological factors (fibrinogen, white cell count). CONCLUSION: Ang I and Ang II do not significantly contribute to the pathogenesis of DR. Patients with DR also had abnormal Lp (a) and haemorheological factors. The role of hypertension in the pathogenesis of DR needs further evaluation.

Aged↗
PubMed1995

Retinal choroidal anastomosis in classic choroidal neovascularization demonstrated by indocyanine green angiography.

Pathologic retinal choroidal anastomoses are relatively rare. Until now, they have been described in age-related macular degeneration only in occult pigment epithelial detachments or following fibrous scarring. We report the occurrence of a retinal choroidal anastomosis with blood flow from an actively proliferating classic choroidal neovascular membrane into a retinal vein in a 72-year-old male with age-related macular degeneration. Indocyanine green videoangiography performed by scanning laser ophthalmoscope demonstrated the anastomosis, whereas it could not be identified clinically or with fluorescein videoangiography.

Aged↗
PubMed1991

Neovascularization of the iris in rhegmatogenous retinal detachment.

To identify conditions associated with neovascularization of the iris in rhegmatogenous retinal detachment, we examined 36 eyes with this disorder seen at our hospital between 1979 and 1990. Clinical courses of disease were divided into the following three groups: (1) neovascularization of the iris without a history of a vitreoretinal operation (four eyes), (2) neovascularization of the iris after an unsuccessful vitreoretinal operation (26 eyes), and (3) neovascularization of the iris after surgical complications (six eyes). In all eyes of Groups 1 and 2, retinal detachment persisted at the onset of iris neovascularization; however, in six eyes, iris neovascularization subsided after retinal reattachment. Characteristic features of Groups 2 and 3 were patient age of 50 years or more, severe myopia, a history of increased intraocular pressure, a history of choroidal detachment, and a large scleral buckle.

Age Factors↗
PubMed1981

Neovascular glaucoma following central retinal vein obstruction.

The results of a prospective clinical and fluorescein angiographic study of 155 patients with central retinal vein obstruction (CRVO) were analyzed to identify risk factors contributing to the subsequent development of iris neovascularization (NVI) and neovascular glaucoma (NVG). Of 144 untreated eyes, 20% developed NVG. The eyes were classified as having either an ischemic or a hyperpermeable type of CRVO according to the extent of retinal capillary nonperfusion demonstrated by the initial fluorescein angiogram. The risk of developing NVG was found to be approximately 60% in those eyes with extensive retinal ischemia. None of the 22 eyes with an ischemic CRVO treated with panretinal photocoagulation (PRP) prior to the onset of NVI developed NVG.

Adult↗
PubMed2003

Presumed combined hamartoma of the retina and retinal pigment epithelium with preretinal neovascularization.

PURPOSE: To describe a case of presumed combined hamartoma of the retina and retinal pigment epithelium associated with preretinal neovascularization. DESIGN: Observational case report. METHODS: We report clinical and angiographic findings of a 26-year-old woman. RESULTS: The patient presented with mild vitreous hemorrhage and slowly decreasing vision in the right eye. A combined hamartoma of the midperipheral retina and retinal pigment epithelium with an epiretinal membrane causing traction to the macula was found. Fluorescein angiography showed areas of capillary nonperfusion and a large preretinal neovascularization peripheral to the hamartoma. CONCLUSIONS: A combined hamartoma may be associated with retinal capillary nonperfusion and preretinal neovascularization, suggesting that significant retinal ischemia can occur with a combined hamartoma.

Adult↗
PubMed1991

Treatment of experimental preretinal neovascularization using photodynamic thrombosis.

Retinal or preretinal neovascularization (NV) is the result of many ischemic conditions of the retina and is an important factor leading to severe visual loss in diabetic retinopathy. Panretinal photocoagulation does not always control its growth or bleeding sequelae. A potential new treatment modality, photodynamic therapy (PDT), was evaluated for limiting the progression of experimental NV in the rabbit eye. The NV was produced by injecting cultured dermal fibroblasts into the preretinal vitreous space after combined enzymatic and mechanical vitreolysis. This method results in traction retinal detachment with a rapid and consistent growth of NV. After administration of the photosensitizing dye rose bengal (20 mg/kg intravenously), PDT was done using a slit-lamp light source focused through a fundus contact lens (45 J/cm2). The NV was treated on two separate occasions during the active phase of growth (on days 13 and 21 after fibroblast injection). Control animals were exposed to light before injection of rose bengal. Eight randomly assigned animals in each group were followed between treatments and for 28 days after the second treatment. The appearance of NV was documented by frequent photography and fluorescein angiography. The PDT resulted in thrombosis of NV for at least 3 days. Reperfusion, however, was consistently noted at 7 days. Thrombosis was associated with a delay in the growth and maturation of NV fronds, which resumed after reperfusion. Twenty-eight days after the second treatment, NV in both experimental and control eyes had undergone atrophy. At that time (the conclusion of follow-up), however, the size of treated NV fronds (estimated from computerized image analysis of fluorescein angiograms) was significantly less than that of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Intraretinal neovascularization in diabetic retinopathy.

Nonperfused retinal areas were evaluated in 60 eyes (42 cases) with diabetic retinopathy through repeated fluorescein angiography. Revascularization occurred in the nonperfused area in 40 eyes, due to recanalization in 3 and to intraretinal neovascularization (IRNV) in 39 eyes. Recanalization and IRNV developed in the same fundus in 2 eyes. IRNVs occurred during the nonproliferative state in 11 eyes, concomitant with retinal neovascularization in 14 and after manifestation of proliferative changes in 14. Typically, IRNVs originated from and drained into a retinal venule, showed hairpin-loop at their tips and manifested minimum tendency of dye leakage. No retinal hemorrhage occurred from the IRNVs. Their unexpectedly high incidence and their timely association with retinal neovascularizations point to the importance of IRNVs in the diagnosis of preproliferative diabetic retinopathy.

Adult↗