Protection of the Retinal Ganglion Cells: Intravitreal Injection of Resveratrol in Mouse Model of Ocular Hypertension.

Purpose: To investigate the efficacy of intravitreal administration of resveratrol (RSV) in a microbead-induced high intraocular pressure (IOP) murine model for glaucoma. Methods: Experiments were performed using adult C57BL/6JJcl mice. Polystyrene microbeads were injected into the anterior chamber to induce IOP elevation. Retinal flat-mounts and sections were assessed by immunohistochemistry to detect the expression of reactive oxygen species and acetyl-p53 in retinal ganglion cells (RGCs), brain-derived neurotrophic factor (BDNF) in Müller glial cells (MGCs), and the receptor tropomyosin receptor kinase B (TrkB) in RGCs. Light cycler real-time PCR was also used for confirming gene expression of BDNF in primary cultured MGCs exposed to RSV. Results: Microbeads induced high IOP followed by RGC death and axon loss. Administration of RSV rescued RGCs via decreased reactive oxygen species generation and acetyl-p53 expression in RGCs and upregulated BDNF in MGCs and TrkB expression in RGCs, which exhibited a strong cytoprotective action against cell death through multiple pathways under high IOP. Conclusions: Our data suggest that administration of RSV may delay the progress of visual dysfunction during glaucoma and may therefore have therapeutic potential.

Visual arrestin modulates gene expression in the retinal pigment epithelium: Implications for homeostasis in the retina.

The retinal pigment epithelium (RPE) is essential for maintaining retinal homeostasis by removing and recycling photoreceptor outer segment (POS) in membranes. It also produces and secretes growth factors involved in retinal homeostasis. Arrestin 1 (ARR1) is specifically expressed in photoreceptors (PRs) and a vital molecule for keeping visual cycle between PRs and RPE. In the present study, we showed the expression of ARR1 was decreased by form-deprivation (FD) in retina of rat. The ARR1 was detected in the RPE of the controls but not in the RPE of FD, which indicates RPE phagocytes POS containing ARR1. Furthermore, we overexpressed ARR1 in cultured human RPE and revealed the ARR1 upregulates bFGF expression and downregulates TGF-ß1, -ß2 and bone morphogenetic protein-2 (BMP-2). The upregulation of bFGF by ARR1 directly works for PR survival and the downregulation of TGF-ßs by ARR1 inhibits epithelial mesenchymal transition (EMT) of RPE, which is the underlying mechanism of keeping retinal homeostasis. Our results also indicate the regulation of ARR1 expression in RPE might become a novel therapeutic option for various ocular diseases.

Potential role of sirtuin 1 in Müller glial cells in mice choroidal neovascularization.

This study investigated the potential role of sirtuin 1 in Müller glial cells in choroidal neovascularization. In the in vitro study, primary Müller glial cells were cultured and treated with resveratrol, a sirtuin 1 activator. Glial fibrillary acidic protein expression and angiogenesis-related gene expression were examined using quantitative polymerase chain reaction and phagocytosis, as a marker of Müller glial cell function; in addition, a latex bead assay was used to analyze cell function. For the in vivo study, choroidal neovascularization was induced in C57BL/6 mice via laser photocoagulation, and resveratrol was administered intravitreally. Eyecup whole mounts were created to measure choroidal neovascularization volumes on day 7. Immunohistochemical analysis with anti-glial fibrillary acidic protein antibody was used to detect Müller glial cell activation in eyes with choroidal neovascularization on day 1, 3, 5, and 7 after laser surgery. Resveratrol significantly promoted glial fibrillary acidic protein, anti-angiogenic factor, pigment epithelium-derived factor, and thrombospondin-1 expression in the cells as well as the phagocytic activities. Treatment of the choroidal neovascularization model with resveratrol resulted in early activation of Müller glial cells near choroidal neovascularization sites. Resveratrol-activated cells but not the controls migrated to the top of choroidal neovascularization sites and into the lesions from day 3. Resveratrol reduced the choroidal neovascularization size relative to controls. In conclusion, sirtuin 1 activation in Müller glial cells suppressed the development of choroidal neovascularization, and therefore, might be a therapeutic option.

Macular Bruch's membrane defect and dome-shaped macula in high myopia.

PURPOSE: To examine an association between macular Bruch's membrane defects (MBMD) and a dome-shaped appearance of the macula (DSM). DESIGN: Retrospective, observational case series study. METHODS: The study included highly myopic individuals who were consecutively examined between May 2014 and December 2015. The patients underwent swept-source optical coherence tomography (OCT) for visualization of DSM and MBMDs defined as Bruch´s membrane defects located at a distance of maximal 1500 µm from the foveola. RESULTS: Out of 1983 highly myopic eyes (1057 patients), 166 eyes (8.4%; 95% confidence interval (CI):7.2%,9.6%)) showed a DSM and 534 eyes showed a MBMD. In multivariate binary regression analysis, higher prevalence of DSM was associated with a higher prevalence of a MBMD (P<0.001; OR: 1.96; 95%CI: 1.40, 2.75) after adjusting for longer axial length (P<0.001; odds ratio (OR): 1.27; 95%CI: 1.16, 1.38). In eyes with a DSM partially surrounded by a MBMD, the retina, retinal pigment epithelium (RPE) and choroid appeared relatively unchanged in the central region with Bruch´s membrane (BM) preserved. In the ring-like BM-free region surrounding the central prominent island of the DSM, the RPE, the outer and middle retinal layers, the choriocapillaris and the middle-sized choroidal vessel layer were absent. In association with a DSM, three MBMD types were differentiated: MBMDs in patchy chorioretinal atrophy, MBMDs in choroidal neovascularization-related macular atrophy, and MBMDs as temporally extending large parapapillary gamma zone. CONCLUSIONS: Presence of a DSM was significantly associated with the presence of MBMDs. The morphology of the DSM in association with MBMDs may be associated with a focal relaxation of the posterior sclera, no longer pushed outward by an expanding BM but allowed to partially bulge inward, leading to the formation of a DSM.

Detection of posterior vortex veins in eyes with pathologic myopia by ultra-widefield indocyanine green angiography.

AIMS: To analyse the characteristics of posterior vortex veins detected in highly myopic eyes by wide-field indocyanine green angiography (ICGA). METHODS: One hundred and fifty-eight consecutive patients (302 eyes) with high myopia (myopic refractive error >8.0 dioptres (D) or axial length ≥26.5 mm) were studied. Wide-field ICGA was performed with the Spectralis HRA module. RESULTS: Posterior vortex veins were found in 80 eyes (26%). The prevalence of posterior staphyloma was significantly higher in eyes in which posterior vortex vein was detected than in eyes without posterior vortex vein. The posterior vortex veins were classified into five types according to the site of exit from the eye; around the optic nerve in 28%, in the macular area in 17%, along the border of staphyloma in 6%, along the margin of macular atrophy or large peripapillary conus in 21%, and elsewhere in 28%. In one eye, two posterior vortex veins collected the choroidal venous blood from the entire fundus. CONCLUSIONS: Wide-field ICGA can analyse the characteristic features of choroidal blood outflow system through posterior vortex veins in highly myopic eyes. They may play an important role as routes of choroidal outflow in highly myopic eyes.

FEATURES OF POSTERIOR STAPHYLOMAS ANALYZED IN WIDE-FIELD FUNDUS IMAGES IN PATIENTS WITH UNILATERAL AND BILATERAL PATHOLOGIC MYOPIA.

PURPOSE: Pigmentary alterations along the presumed edge of staphyloma in wide-field fundus images have been reported to be highly correlated with the eye shape in three-dimensional magnetic resonance images. The purpose of this study was to analyze Optos images in a large series of highly myopic patients to determine the prevalence, types, and features of staphylomas. METHODS: One thousand and sixty eyes of 541 patients with high myopia (axial length ≥ 26.5 mm) in at least one eye were retrospectively analyzed in Japan and Spain. To determine the presence and types of staphyloma, the authors focused on pigmentary abnormalities along the presumed edge of staphylomas with at least one positive finding in fundus images, autofluorescent images, and infrared images by Optos. RESULTS: Posterior staphyloma was detected in 552 of 1,060 eyes (55%) in Optos images. Wide macular type was the most common (79%), followed by narrow macular (15%), then peripapillary (3%), inferior, and finally nasal. In the 60 non-highly myopic eyes of patients with unilateral high myopia, staphyloma was detected in 40%, suggesting that unilateral high myopia might be a bilateral disorder with marked differences in the degree of staphyloma between the two eyes. Combined staphylomas such as the peripapillary type within the wide macular type were also found. CONCLUSION: Posterior staphyloma was found in 55% of 1,060 eyes with bilateral or unilateral pathologic myopia. Wide macular was the most common type, although there were much more variations in the shape of staphylomas than that had been previously believed.