Altération de la morphologie astrocytaire et du développement vasculaire chez les souris Ko-Dp71 : implications dans la barrière hémato rétinienne interne

Dp71, a dystrophin produced from DMD gene, is involved in retinal homeostasis and maintenance of blood retinal barrier. We have previously shown that Dp71, part of a complex called Dystrophin associated protein, is involved in the localization of aqueous and potassic channels in Muller glial cell (MGC), particularly around blood vessels, allowing maintenance of retinal homeostasis. Based on the knowledge that growing retinal vessels migrate on an astrocyte template during development, we highlighted the expression of Dp71 in retinal astrocytes. In absence of Dp71, in vivo, we observed a lower density and a different morphology of retinal astrocytes compared to control retina in mice, responsible for a delayed vascular development. Due to the role of barrier of the retinal vascular network, insured also by astrocytes, we studied a model of post surgical BRB breakdown and found a decreased of Dp71 protein expression associated with Kir4.1 delocalization and AQP4 decrease in MGC. Intravitreal Dexamethasone prevents these protein expression changes. We suggest here that the membrane associated cytoskeletal protein, Dp71, expressed in astrocytes is involved in the maintenance of astrocytes density and morphology necessary as a template for retinal vascular development. This protein insure also a key role in retinal homeostasis by localizing and maintaining aqueous and potassic channels in MGC. Moreover when this protein is altered, Dexamethasone seems to be capable to promote Dp71 expression which could have wide clinical implications in retinal diseases treatment and the target for retinal neuroprotection under pathological conditions seems to be the macroglial cells.La dystrophine Dp71, issue du gène DMD impliqué dans la dystrophie musculaire de Duchenne intervient dans le maintien de l'homéostasie rétinienne et de la barrière hémato-rétinienne. Nous avons mis en évidence une localisation rétinienne jusque-là méconnue de la Dp71 au sein des astrocytes rétiniens. Nous avons également étudié l'effet in vivo de l'absence de Dp71, sur le développement vasculaire et observé une plus faible densité et une morphologie astrocytaire différente comparativement aux souris contrôles, à l'origine d'un développement vasculaire retardé. Compte tenu de la spécificité du réseau vasculaire rétinien dont l'étanchéité des parois est maintenue en partie par les pieds des CGM et des astrocytes, nous avons émis l'hypothèse, étant donné l'implication de la Dp71 dans la stabilisation de ces cellules, d'une altération de cette protéine dans les phénomènes de rupture de la BHR. Ainsi dans un modèle transitoire de rupture de la BHR in vivo relativement " pur ", sans ischémie ni injection de VEGF, nous avons observé une diminution de l'expression de la dystrophine Dp71 ainsi que du canal aqueux AQP4 et une délocalisation du canal potassique Kir4.1 dans les CGM. L'injection intra-vitréenne de Dexaméthasone dans ce modèle a permis de prévenir les modifications d'expression et de localisation de ces protéines

Real-world management of macular edema secondary to retinal vein occlusion with intravitreal aflibercept: 24-month results from the AURIGA observational study

Introduction: AURIGA is the largest real-world study to date to evaluate intravitreal aflibercept (IVT-AFL) treatment of diabetic macular edema or macular edema secondary to retinal vein occlusion (RVO) in routine clinical practice. Here, we report the 24-month outcomes in the RVO cohort from France, Germany, Italy, and Taiwan.MethodsAURIGA (NCT03161912) was a prospective observational study. Eligible patients with RVO were enrolled for whom the decision to treat with IVT-AFL had already been made by the attending physician. Patients were treated with IVT-AFL for up to 24 months at physician discretion according to local practice. The primary endpoint was mean change in visual acuity (VA; Early Treatment Diabetic Retinopathy Study [ETDRS] letters) from baseline to month (M) 12. All statistical analyses were descriptive.ResultsIn 554 treatment-naive and 65 previously treated patients with RVO, the respective mean (95% confidence interval) change in VA from baseline was + 12.5 (10.8, 14.3) and + 7.9 (3.3, 12.6) letters by M12 and + 11.4 (9.4, 13.3) and + 4.4 (- 0.6, 9.5) letters by M24 (baseline mean +/- standard deviation: 51.0 +/- 21.9 and 51.9 +/- 20.4 letters); 44.0% of treatment-naive and 27.9% of previously treated patients reported >= 15-letter gains by M24. By M24, the mean change in central retinal thickness from baseline was - 247 (- 267, - 227) mu m in treatment-naive patients and - 147 (- 192, - 102) mu m in previously treated patients. From baseline to M6, M12, and M24, treatment-naive patients received a total of 4.0 +/- 1.3, 5.5 +/- 2.5, and 6.9 +/- 4.2 injections, respectively, and previously treated patients received 3.8 +/- 1.5, 5.0 +/- 2.2, and 6.3 +/- 3.7 injections, respectively. The safety profile of IVT-AFL was consistent with that of previous studies.ConclusionsIn AURIGA, patients with RVO experienced clinically relevant functional and anatomic improvements following IVT-AFL treatment in routine clinical practice. These improvements were largely maintained in treatment-naive patients over the 24-month study despite the decreasing treatment frequency, suggesting long-term durability of IVT-AFL treatment outcomes. Infographic available for this article.Trial RegistrationClinicalTrials.gov Identifier: NCT03161912 (May 19, 2017)

Intravitreal Aflibercept for the treatment of diabetic macular edema in routine clinical practice: results from the 24-Month AURIGA observational study

Introduction AURIGA is the largest real-world study to date to evaluate intravitreal aflibercept (IVT-AFL) in the treatment of diabetic macular edema (DME) or macular edema secondary to retinal vein occlusion in routine clinical practice. The 24-month outcomes in the DME cohort from across 11 participating countries are reported here.MethodsAURIGA (NCT03161912) was a prospective observational study. The study enrolled eligible patients with DME for whom the decision to treat with IVT-AFL had previously been made by the attending physician. Patients were treated with IVT-AFL for up to 24 months at physician discretion according to local practice. The primary endpoint was mean change in visual acuity (VA; Early Treatment Diabetic Retinopathy Study [ETDRS] letters) from baseline to month 12 (M12). All statistical analyses were descriptive.ResultsIn 1478 treatment-naive and 384 previously treated patients with DME, the mean (95% confidence interval) change in VA from baseline was +6.7 (5.7, 7.6) and +7.4 (5.5, 9.4) letters by M12 and +5.9 (4.9, 6.9) and +8.1 (6.1, 10.1) letters by M24 (baseline [mean +/- standard deviation]: 56.0 +/- 19.8 and 50.8 +/- 19.5 letters), respectively; 25.9% of treatment-naive and 32.8% of previously treated patients achieved >= 15-letter gains by M24. The mean change in central retinal thickness from baseline to M24 was -110 (-119, -102) mu m in treatment-naive patients and -169 (-188, -151) mu m in previously treated patients. By M6, M12, and M24, treatment-naive patients had received 3.8 +/- 1.7, 4.9 +/- 2.8, and 5.7 +/- 3.9 injections, respectively, and previously treated patients had received 3.9 +/- 1.5, 4.9 +/- 2.4, and 6.2 +/- 3.6 injections, respectively. The safety profile of IVT-AFL was consistent with previous studies.ConclusionIn AURIGA, treatment-naive and previously treated patients with DME achieved clinically relevant functional and anatomic improvements following IVT-AFL treatment for up to 24 months in routine clinical practice. Even with the decreasing injection frequency observed, these gains were largely maintained throughout the study, suggesting long-term durability of the positive effects of IVT-AFL treatment. Infographic available for this article.Trial RegistrationClinicalTrials.gov Identifier: NCT03161912 (May 19, 2017)

Protection of Glial Müller Cells by Dexamethasone in a Mouse Model of Surgically Induced Blood-Retinal Barrier Breakdown.

Purpose: Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may cause retinal edema often responsible for vision loss. Dexamethasone is used in clinical practice to restore iBRB. The aim of this study was to characterize the impact of a surgically induced iBRB breakdown on retinal homeostatic changes due to dystrophin Dp71, aquaporin-4 (AQP4), and Kir4.1 alterations in Müller glial cells (MGC) in a mouse model. The protective effect of dexamethasone was assessed in this model. Moreover, retinal explants were used to control MGC exposure to a hypoosmotic solution containing barium. Methods: Partial lens surgery was performed in C57BL6/J mice. Dystrophin Dp71, AQP4, and Kir4.1 expression was analyzed by quantitative RT-PCR, Western blot, and immunohistochemistry. Twenty-four hours after surgery, mice received a single intravitreal injection of dexamethasone or of vehicle. Results: After partial lens surgery, iBRB permeability increased while Dp71 and AQP4 were downregulated and Kir4.1 was delocalized. These effects were partially prevented by dexamethasone injection. In the retinal explant model, MGC were swollen and Dp71, AQP4, and Kir4.1 were downregulated after exposure to a hypoosmotic solution containing barium, but not in the presence of dexamethasone. Heat shock factor protein 1 (HSF1) was overexpressed in dexamethasone-treated retinas. Conclusions: Partial lens surgery induces iBRB breakdown and molecular changes in MGC, including a downregulation of Dp71 and AQP4 and the delocalization of Kir4.1. Dexamethasone seems to protect retina from these molecular changes by upregulating HSF1

Astrocytes morphology and retinal vascular development alterations in Ko-Dp71 mice : impact on blood retinal barrier

La dystrophine Dp71, issue du gène DMD impliqué dans la dystrophie musculaire de Duchenne intervient dans le maintien de l'homéostasie rétinienne et de la barrière hémato-rétinienne. Nous avons mis en évidence une localisation rétinienne jusque-là méconnue de la Dp71 au sein des astrocytes rétiniens. Nous avons également étudié l'effet in vivo de l'absence de Dp71, sur le développement vasculaire et observé une plus faible densité et une morphologie astrocytaire différente comparativement aux souris contrôles, à l'origine d'un développement vasculaire retardé. Compte tenu de la spécificité du réseau vasculaire rétinien dont l'étanchéité des parois est maintenue en partie par les pieds des CGM et des astrocytes, nous avons émis l'hypothèse, étant donné l'implication de la Dp71 dans la stabilisation de ces cellules, d'une altération de cette protéine dans les phénomènes de rupture de la BHR. Ainsi dans un modèle transitoire de rupture de la BHR in vivo relativement " pur ", sans ischémie ni injection de VEGF, nous avons observé une diminution de l'expression de la dystrophine Dp71 ainsi que du canal aqueux AQP4 et une délocalisation du canal potassique Kir4.1 dans les CGM. L'injection intra-vitréenne de Dexaméthasone dans ce modèle a permis de prévenir les modifications d'expression et de localisation de ces protéines.Dp71, a dystrophin produced from DMD gene, is involved in retinal homeostasis and maintenance of blood retinal barrier. We have previously shown that Dp71, part of a complex called Dystrophin associated protein, is involved in the localization of aqueous and potassic channels in Muller glial cell (MGC), particularly around blood vessels, allowing maintenance of retinal homeostasis. Based on the knowledge that growing retinal vessels migrate on an astrocyte template during development, we highlighted the expression of Dp71 in retinal astrocytes. In absence of Dp71, in vivo, we observed a lower density and a different morphology of retinal astrocytes compared to control retina in mice, responsible for a delayed vascular development. Due to the role of barrier of the retinal vascular network, insured also by astrocytes, we studied a model of post surgical BRB breakdown and found a decreased of Dp71 protein expression associated with Kir4.1 delocalization and AQP4 decrease in MGC. Intravitreal Dexamethasone prevents these protein expression changes. We suggest here that the membrane associated cytoskeletal protein, Dp71, expressed in astrocytes is involved in the maintenance of astrocytes density and morphology necessary as a template for retinal vascular development. This protein insure also a key role in retinal homeostasis by localizing and maintaining aqueous and potassic channels in MGC. Moreover when this protein is altered, Dexamethasone seems to be capable to promote Dp71 expression which could have wide clinical implications in retinal diseases treatment and the target for retinal neuroprotection under pathological conditions seems to be the macroglial cells

Proliferative Sickle Cell Retinopathy in the Retinal Periphery Detected by Ultra-Widefield Imaging: A Case Report

Sickle cell proliferative retinopathy usually presents first in the peripheral retina and the ability to extend and enhance our visualization of the peripheral retina would allow for superior clinical decision-making. In our practice, we had a 28-year-old patient diagnosed with major sickle cell disease of the homozygous type SS (HbSS) that presented with sickle cell proliferative retinopathy detected by ultra-widefield imaging in the nasal side of the left fundus. At follow-up, neovascularization was detected in the extreme nasal periphery of the left eye by ultra-widefield imaging fluorescein angiography with right gaze. The case was graded as Goldberg stage 3, and the patient was administered photocoagulation treatment. With further advancements in the quality and modality of peripheral retinal imaging, novel proliferative lesions can be detected and appropriately managed much earlier than was previously possible. Ultra-widefield imaging allows for the visualization of the central 200 degrees of the retina but, with gaze view, peripheral retina beyond 200 degrees can be reached

Reduced Vessel Density in the Mid-Periphery and Peripapillary Area of the Superficial Capillary Plexus in Non-Proliferative Diabetic Retinopathy

Our aim in this study was to assess the vessel density (VD) and vessel skeleton density (VSD) in the nasal area of the superficial capillary plexus (SCP) of diabetic subjects without diabetic retinopathy (DR), or in those with a non-proliferative diabetic retinopathy (NPDR), and to evaluate the relationship between the VD and VSD and the severity of DR. In this prospective study, the VD and VSD in the SCP were measured and analyzed on 6 × 6-mm macular and nasal optical coherence tomography angiography scans. The three concentric circles of the Early Treatment of Diabetic Retinopathy Study (ETDRS) grid were used and divided into zones numbered from 1 to 9 in the macular area and from 1 to 8 in the nasal area. The VD was significantly lower in the nasal peripapillary area (p = 0.0028), and both the VD and VSD were significantly lower in the macular area (p = 0.0131 and p = 0.0132, respectively) in patients with more severe DR. The SD was significantly lower in zones 5 (p = 0.0315) and 6 (p = 0.0324) in the nasal grid in patients with more severe DR. We showed a lower superficial capillary flow in the nasal periphery and peripapillary area in patients with more severe DR

Comparison of the Effect of Ranibizumab and Aflibercept on Changes in Macular Choroidal Thickness in Patients Treated for Diabetic Macular Edema

Purpose. The aim of this study was to assess the effect of intravitreal injections (IVI) of ranibizumab and aflibercept on the choroidal thickness (CT) in patients with treatment-naive diabetic macular edema (DME) before and after monthly IVI. Patients and Methods. Prospective monocenter study. Inclusion criteria were treatment-naive DME eyes without concomitant panretinal photocoagulation, associated with a decrease in best-corrected visual acuity ≤75 letters on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. DME was defined by a central retinal thickness ≥300 μm on swept-source OCT (Triton DRI OCT, Topcon Corporation, Itabashi, Japan). Patients received 5 IVI of ranibizumab or aflibercept. The primary endpoint was the change in the central subfield CT (CSCT) between inclusion (M0) and 1 month after the fifth IVI (M5). The secondary endpoint was the CT changes between M0 and M5 in other locations of the macular ETDRS grid. Results. Twenty-four eyes of 24 patients with a mean age of 61.1 years were included. Eleven and 13 patients were, respectively, treated with ranibizumab and aflibercept, and 86.4% had type 2 diabetes. The overall CSCT decreased significantly by −12 μm between M0 and M5 (231.7 μm at M0 and 219.7 μm at M5) (p=0.03). It decreased by −15.2 μm (p=0.02) in the aflibercept group (206.9 μm at M0 and 191.7 μm at M5) and by −7.3 μm (p=0.4) in the ranibizumab group (267.5 μm at M0 and 260.2 μm at M5). The CSCT decreased by −4.9 μm in noninjected contralateral eyes (242.3 μm at M0 and 237.4 μm at M5). CT changes between M0 and M5 in the superior, temporal, inferior, and nasal macular inner ring were significant in the aflibercept group but not in the ranibizumab and control groups. Conclusion. In DME patients, the CSCT decreases after 5 IVI of anti-VEGF, especially after aflibercept treatment