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At least 1,531 records · Page 85Linked to original sources
PubMed2005

A potential role for beta- and gamma-crystallins in the vascular remodeling of the eye.

We demonstrate that expression of beta- and gamma-crystallins is associated with intraocular vessels during normal vascular development of the eye and also in the Nuc1 rat, a mutant in which the hyaloid vascular system fails to regress normally. Real-Time RT PCR, Western blot and metabolic labeling studies indicate an increased expression of beta- and gamma-crystallins in Nuc1 retina. The increased expression of crystallins was localized to the astrocytes surrounding the intraocular vessels. A similar pattern of crystallin expression was also observed in the retinal vessels during normal development. Cultured human astrocytes exposed to 3-nitropropionic acid, an established model of neuronal hypoxia, increased VEGF expression, as expected, but also increased expression of crystallins. Our data suggest that crystallins may function together with VEGF during vascular remodeling. Interestingly, in human PFV (persistent fetal vasculature) disease, where the hyaloid vasculature abnormally persists after birth, we show that astrocytes express both VEGF and crystallins.

Animals↗
PubMed1998

Optic disc morphology in pigmentary glaucoma.

AIM: To evaluate the morphology of the optic nerve head in eyes with pigmentary glaucoma. METHODS: Colour stereo optic disc photographs of 62 patients with pigmentary glaucoma and 566 patients with primary open angle glaucoma were morphometrically evaluated. By prestudy selection, mean visual field defect and neuroretinal rim area were not significantly different between the two groups (p = 0.89 and p = 0.45). RESULTS: The pigmentary glaucoma group did not vary significantly (p > 0.10) from the primary open angle glaucoma group in size and shape of the optic disc, configuration of neuroretinal rim, depth of optic cup, area of alpha zone of parapapillary atrophy, diameter of retinal vessels at the disc border, and frequency of disc haemorrhages and localised retinal nerve fibre layer defects. The beta zone of parapapillary atrophy was slightly, but not statistically significantly (p = 0.06), smaller in the pigmentary glaucoma group. The mean maximal intraocular pressure and mean intraocular pressure amplitude were significantly (p < 0.001) higher in the pigmentary glaucoma group. CONCLUSIONS: In contrast with the characteristic morphology of the anterior segment and despite significantly higher intraocular pressure peaks and a larger pressure amplitude, eyes with pigmentary glaucoma compared with eyes with primary open angle glaucoma do not show a pathognomonic morphology of the optic disc and retinal nerve fibre layer. The slightly smaller beta zone of parapapillary atrophy may correspond to higher intraocular pressure in pigmentary glaucoma.

Adult↗
PubMed1978

Retinal angiography in the study of cerebral ischemia.

On the basis of the assumption of an affinity between cerebral and retinal vessels, it was sought to demonstrate that the variations induced in the retinal circulation are akin to those occurring at the cerebral level. The technique of retinal fluorescein angiography was used to evaluate the amplitude of the vasal lumen and the speed of circulation. In 5 patients, the drug used was (-)eburnamonine. While the calibre of the retinal arterioles did not undergo variations, a shortening of the mean transit time was observed in 3 of the 5 cases treated, evidencing an improvement in blood flow.

Brain Ischemia↗
PubMed1976

Components of vitreous-soluble proteins: effect of hyperoxia and age.

In young puppies, the retina, which is incompletely vascularized at birth becomes fully vascularized at approximately four weeks of age. During this period of vessel growth the total content of vitreous-soluble protein was found closely associated with the rate of retinal vessel growth. As vascularization progressed toward completion, the protein originally present at birth decreased to a negligible or undetected amount. Intravitreal neovascularization was produced in young puppies by exposure to 85 per cent oxygen for four days, then removal to room air. This form of neovascularization resembles closely that observed in human proliferative diabetic retinopathy. The oxygen treatment, which initially produced retinal capillary closure, then neovascularization, was associated with a retention of vitreous-soluble protein at a high level for several days. The results raise the possibility that the vitreous protein(s) may be fundamentally involved in the process of normal vascularization of the retina and in retinal neovascularization.

Age Factors↗
PubMed1976

Retinal detachment and pathology following experimental embolization of choroidal and retinal circulation.

By means of a micro-surgical technique, the central retinal artery of the owl monkey (Aotus trivirgatus) was embolized with spheric plastic beads (7-25 mu in diameter). Beads (4-15 mu) were also injected into choroidal capillaries through a supero-temporal vortex vein. Choroidal ischemia induced proliferation or degerneration of the pigment epithelium, frequently accompanied by photoreceptor degeneration and circumscribed retinal detachment. Occlusion of retinal vessels resulted in posterior vitreous detachment and micro-cystoid degeneration in inner retinal layers, followed by retinal schisis. In combined retinal and choroidal ischemia long-lasting retinal detachments regularly developed.

Animals↗
PubMed1997

[Topography of fundus autofluorescence with a new confocal scanning laser ophthalmoscope].

BACKGROUND: We investigated fundus autofluorescence in vivo using a novel scanning laser ophthalmoscope. MATERIALS AND METHODS: A total of 550 patients with various retinal diseases were examined and compared with normal eyes. Autofluorescence was detected after excitation with an argon blue laser (488 nm), and emission was recorded with a short wavelength cut off above 500 nm. RESULTS: Reduced autofluorescence was observed in the foveal and parafoveal region due to retinal xanthophyll, along the retinal vessels, at the optic nerve head and in areas with atrophy of the retinal pigment epithelium (RPE). Autofluorescence intensity was increased either focally or diffusely in certain degenerative (AMD) or genetically determined retinal diseases (e.g., Stargardt's disease, Best's disease). CONCLUSIONS: These findings are in accordance with the view that in vivo fundus autofluorescence originates at the level of the RPE and suggest that it is derived from lipofuscin.

Adolescent↗
PubMed1991

Acute multifocal inner retinitis.

Two patients developed acute changes in vision two to four weeks after a febrile illness. On ophthalmic examination, each patient had bilateral vitreitis without anterior segment inflammation and multiple, bilateral, round, yellow-white inner retinal lesions that were located in the posterior pole and midperiphery. Laboratory tests did not contribute to a diagnosis. Symptomatic visual loss was caused by neuroretinitis and serous retinal detachment in one patient and by an occluded branch retinal artery in the other. The multifocal retinal lesions resolved gradually without treatment over several months with minimal or no residual retinal changes. Acute multifocal inner retinal lesions may be associated with a preceding nonspecific viral illness and may cause a sudden change in vision if associated with neuroretinitis, serous retinal detachment, or retinal vessel occlusion. We have termed this constellation of ophthalmic findings acute multifocal inner retinitis.

Acute Disease↗
PubMed2000

[Monitoring of morphometric changes of optic discs with morphologic progression of glaucomatous optic atrophy by means of laser scanner tomography].

AIM: Aim of this study was to measure morphometric changes in optic discs with laser-scanning tomography (HRT, Heidelberg-Retina-Tomograph, Heidelberg) in eyes with early glaucomatous morphologic progression. PATIENTS AND METHODS: 61 eyes of 36 patients with marked neuroretinal rim loss or its early morphologic signs (1. optic disc hemorrhages, 2. reduced visibility of the retinal nerve fiber layer (RNF), 3. appearance of narrowing of retinal vessels, 4. enlargement of the choroidal, parapapillary atrophy) were compared to 74 normal eyes of 39 probands. 15 degrees stereographs of the optic discs were evaluated for morphologic changes. The morphometric variables of the neuroretinal rim and excavation measured by the HRT were examined in the course of the disease. RESULTS: In the group of normals no significant changes of the neuroretinal rim in the course of 2.0 +/- 1.2 years were found. In the group of glaucomatous eyes (3.0 +/- 1.5 years follow-up) 34 eyes showed marked neuroretinal rim loss, 17 disc hemorrhages, 4 vessel narrowing, 3 an increased chorioidal atrophy, 3 a decreased visibility of the retinal nerve fiber layer. In these eyes a significant loss of rim area (p = 0.01) and an increase of excavation area (p = 0.0001) and volume (p = 0.003) was measured by the HRT. Only three eyes showed a perimetric loss of sensitivity (0.8-3.4 db) in Octopus static perimetry. CONCLUSIONS: Laser-scanning tomography of the optic disc seems to be able to measure morphometric changes in eyes with morphologic progression of glaucomatous optic atrophy, even before perimetric changes occur.

Adult↗
PubMed2003

Reduced retinal angiogenesis in MMP-2-deficient mice.

PURPOSE: To study the putative role of endogenous matrix metalloproteinases (MMPs) in retinal neovascularization, an established mouse model was used to compare the retinal neovascularization observed in wild-type mice with that in mice without the MMP-2 or -9 genes. METHODS: C57Bl/6 (MMP-2(+/+) and -9(+/+)), MMP-2-deficient (MMP-2(-/-)), and MMP-9-deficient (MMP-9(-/-)) mice were used. After oxygen-induced retinopathy was induced in the mice, their eyes were rapidly removed and frozen in optimal cutting temperature embedding compound. Sections were histochemically stained with specific markers for vascular cells and angiogenesis-related factors. The area of new retinal vessels was measured using image-analysis software and compared between groups. RESULTS: Retinal neovascularization was not significantly different between wild-type and MMP-9(-/-) mice. The MMP-2(-/-) mice had significantly less extraretinal neovascularization than did wild-type mice. The mean number of extraretinal neovascular buds per cross section was significantly lower in MMP-2(-/-) mice than in wild-type mice (P < 0.05). The expression of other angiogenesis-related factors, vascular endothelial growth factor and pigment epithelium-derived factor, was not different between wild-type and MMP-2(-/-) mice. CONCLUSIONS: MMP-2 may be essential in the regulation of retinal neovascularization. Pharmacologic intervention using MMP inhibitors may be a future therapeutic approach for angiogenic retinal diseases.

Animals↗
PubMed2001

Effect of the absence of heat shock protein 70.1 (hsp70.1) on retinal photoreceptors in normal and rd mice.

The purposes of this study are to elucidate the retinal changes of heat shock protein 70.1 (hsp70.1) knockout mice and to compare them between in normal and in retinal degeneration (rd) mice. Eyes of hsp70.1 wild type (+/+) and knockout (-/-) mice in the C57BL/6 or FVB genetic backgrounds respectively, which were reared in the normal environment, were examined by fundus photography, electroretinography, light microscopy, terminal dUTP nick-end labeling (TUNEL) stain, and immunohistochemistry. In C57BL/6 mice, fundus photography showed no changes between hsp70.1+/+ and -/- mice at 1 and 6 months of age. Electroretinographic examination showed a tendency of decreased amplitude of a- and b-wave with aging in both genotype, but there were not different statistically. The ratios of the thickness of inner nuclear and outer nuclear layer to the retinal thickness were respectively decreased with aging in both genotype, but there were not different statstically. TUNEL assay showed a few positively labeled cells in the ganglion cell, inner nuclear and outer nuclear layers and the immunohistochemistry showed no immunopositivity of hsp70 in the inner segments of photoreceptor cell layer in both genotype. In rd mice, fundus photography showed a narrowing of the retinal vessels at the age of 4 weeks, however, there were no differences of retinal changes including pigment epithelial layer in both genotype. Electroretinographic examination at the postnatal 2, 3 and 4 weeks showed no differences between them. Loss of photoreceptor cell and outer nuclear layers showed no differences in both genotype. In conclusion, there were no differences of the retinal changes at least under the normal environmental condition in hsp70.1+/+ and -/- mice. These results show that hsp70.1-/- mice can be used to study the role of hsp70.1 to the external stress to the retina.

Animals↗
PubMedDate not supplied

[Connection between severe perivenous retinitis with retinovitreal hemorrhage and disseminated sclerosis].

In a 49-year-old man with temporal pallor of the left optic nerve papilla and increasing spastic paraparesis and with slight lymphocytosis in the cerebrospinal fluid perivenous retinitis was diagnosed. The peripheral retinal veins were covered with characteristic white sheaths, focal formation of new blood vessels, retinal microscopic haemorrhages and residues after vitreal haemorrhage were found. The authors discuss the possibility of a connection between disseminated sclerosis and perivenous retinitis and their possible common aetiology.

Humans↗
PubMed1990

Vascular permeability and coagulation during Rickettsia rickettsii infection in dogs.

The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were studied in dogs following intradermal inoculation with 5 x 10(5) TCID50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery. Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma TXB2 and 6-keto-PGF1 alpha concentrations were not increased.

6-Ketoprostaglandin F1 alpha↗
PubMed1979

[Massive subretinal fat and lipoid deposits (author's transl)].

Both in exsudative retinitis (Coats disease 4 cases [presumed angioma of the chorioid in 1 case]), and in the exsudative form of senile macular degeneration (1 case), massive subretinal fat and lipoid deposits were observed. These form a yellowish central disc approximately between the upper and lower lateral retinal vessels. The centre of the subretinal depositis, and therefore the highest point of retinal detachment (3 dioptres), appears white.

Child↗
PubMed2004

Persistence of fetal vasculature in a patient with Knobloch syndrome: potential role for endostatin in fetal vascular remodeling of the eye.

OBJECTIVE: To report a child with Knobloch syndrome (KS) with features of persistent fetal vasculature (PFV) and to discuss the possible role of endostatin in vascular remodeling of the fetal eye. DESIGN: Case report with enzyme-linked immunosorbent assay (ELISA) analysis of serum endostatin. MAIN OUTCOME MEASURES: Ocular examination, fluorescein angiography, echography, ELISA analysis of serum endostatin, and typing for pathogenic mutations in COL18A1. RESULTS: Slit-lamp examination in the left eye disclosed numerous findings of PFV, including an extensive persistent pupillary membrane, scarcity of iris crypts, and pigmented epicapsular stellate remnants on the anterior lens surface. Dilated fundus examination revealed a total posterior vitreous detachment, despite the young age of the patient, with numerous white intragel opacities that were compatible with remnants of the vasa hyaloidea propria. The fundus had a tesselated appearance with angiographically visible large choroidal vessels. There was a retinochoroidal staphyloma inferotemporal to the optic disc. There were no retinal vessels visible temporally, and there was no macular differentiation or foveal pit. Competitive ELISA analysis disclosed no detectable serum endostatin. None of the 8 reported pathogenic mutations in the COL18A1 gene was found in the patient. CONCLUSIONS: Persistent fetal vasculature may be a clinical and important manifestation in some patients with KS and can be explained by a deficiency in endostatin. Endostatin deficiency may result in reduced or delayed regression of fetal blood vessels in the eye (including the intravitreal compartment), thereby resulting in incomplete development of the normal vasculature in the retina. Our typing results for the reported COL18A1 mutations confirm the genetic heterogeneity of KS.

Cerebellum↗
PubMed2004

Retinal arteriolar narrowing is associated with 5-year incident severe hypertension: the Blue Mountains Eye Study.

We assessed whether retinal arteriolar narrowing and structural abnormalities independently predicted 5-year incident severe (grade 2 or 3) hypertension in an older population-based cohort. The Blue Mountains Eye Study baseline (1992 to 1994) examined 3654 residents aged 49 and older in 2 postal code areas, west of Sydney. Of the 2335 participants (75.1% of survivors) who returned at the 5-year examinations, 1319 were normotensive or had mild (grade 1) hypertension at baseline. Baseline retinal photographs were graded for focal retinal vessel wall signs and vessel diameters were measured. Participants were classified as having normal, high-normal blood pressure [BP] (systolic BP 121 to 139 mm Hg and/or diastolic BP 81 to 89 mm Hg), mild hypertension (systolic BP 140 to 159 mm Hg and/or diastolic BP 90 to 99 mm Hg), or severe hypertension if they had a previous diagnosis of hypertension and were receiving antihypertensive medications or had systolic BP > or =160 mm Hg and/or diastolic BP > or =100 mm Hg at examination. Incident severe hypertension was defined in persons who were free of severe hypertension at baseline but classified as having severe hypertension at the 5-year examinations. Of the 1319 baseline subjects at risk, 390 (29.6%) developed severe hypertension. After adjusting for age, sex, body mass index, smoking, glucose, and total cholesterol, generalized retinal arteriolar narrowing at baseline was associated with increased risk of incident severe hypertension (odds ratio 2.6; 95% confidence interval, 1.7 to 3.9) when comparing the narrowest versus widest quintile. This association remained significant after further adjustment for baseline mean arterial BP or BP status. Our findings support the hypothesis that small vessel structural changes may precede the development of severe hypertension.

Aged↗
PubMed2004

Development and pathology of the hyaloid, choroidal and retinal vasculature.

During embryogenesis, the development and differentiation of the eye requires the concomitant formation of the neural/glial elements along with a dense vascular network. The adult neural retina is supported by two distinct vascular systems, the proper retinal vessels and the choroidal vessels. The two beds differ not only in their pattern of embryonic differentiation, but also in their function in the adult organism. The retinal vasculature has barrier properties similar to those observed in the brain, whereas the choroidal vessels display a highly fenestrated phenotype. The hyaloid vasculature is a transient embryonic vascular bed which is complete at birth in mammals and regresses contemporaneously with the formation of the retinal vasculature. The dependence of the retina on its blood supply makes it highly vulnerable to any vascular changes and indeed ocular diseases, such as proliferative retinopathy, age-related macular degeneration and the hyperplastic primary vitreous, which are associated with abnormalities of the different vascular beds of the eye. A number of factors have been implicated in developmental and pathological changes in vessel formation and regression, including fibroblast growth factors, platelet-derived endothelial growth factor and vascular endothelial growth factor, among others. The purpose of this review is to describe and discuss new insights into the mechanisms and molecular cues involved in the development of the normal and pathological vascular systems of the eye. The characterization of the molecules and cell-cell interactions involved in the formation, stabilization and regression of new vessels has led to the identification of potential control points for therapeutic intervention.

Animals↗
PubMed1986

Retinopathy of prematurity: the influence of gestational age and retinal maturity on the statistical behavior of risk factors.

The clinical and laboratory data on 140 premature infants, 74 cases with retinopathy of prematurity (ROP) and 66 control cases without ROP, were correlated with ROP grades of increasing severity. By using multiple linear regression (MLR), it is shown that for predicting ROP grades the importance of certain variables varies considerably depending on the gestational age. Below 32 weeks of gestation, acidosis, hyperoxemia, gestational age, pathologic paCO2 levels, and multiple birth are strong regressors. Above 31 weeks, the most important regressors are multiple birth and acidosis, while gestational age and duration of FiO2 greater than 0.4 are much less influential. Blood transfusions and artificial ventilation do not seem important in the MLR of either group. When ROP is regressed on the number of paO2 values above 100 torr and gestational age or on the number of paCO2 values above 50 torr and gestational age, the regression coefficients of these variables drop to near zero at a gestational age of about 32 weeks. This loss of weight of the two variables paO2 and paCO2 with increasing gestational age coincides with a comparable drop of the relative incidence of ROP and the relative incidence of immature retinal vessels. It is hypothesized that it is the proportion of infants with an immature retinal vasculature in populations of given gestational ages rather than the gestational age itself which is responsible for the widely varying importance of certain factors during the development of ROP.

Gestational Age↗