Hypoxia Inhibits Subretinal Inflammation Resolution Thrombospondin-1 Dependently

International audienceHypoxia is potentially one of the essential triggers in the pathogenesis of wet age-related macular degeneration (wetAMD), characterized by choroidal neovascularization (CNV) which is driven by the accumulation of subretinal mononuclear phagocytes (MP) that include monocyte-derived cells. Here we show that systemic hypoxia (10% O2) increased subretinal MP infiltration and inhibited inflammation resolution after laser-induced subretinal injury in vivo. Accordingly, hypoxic (2% O2) human monocytes (Mo) resisted elimination by RPE cells in co-culture. In Mos from hypoxic mice, Thrombospondin 1 mRNA (Thbs1) was most downregulated compared to normoxic animals and hypoxia repressed Thbs-1 expression in human monocytes in vitro. Hypoxic ambient air inhibited MP clearance during the resolution phase of laser-injury in wildtype animals, but had no effect on the exaggerated subretinal MP infiltration observed in normoxic Thbs1−/−-mice. Recombinant Thrombospondin 1 protein (TSP-1) completely reversed the pathogenic effect of hypoxia in Thbs1−/−-mice, and accelerated inflammation resolution and inhibited CNV in wildtype mice. Together, our results demonstrate that systemic hypoxia disturbs TSP-1-dependent subretinal immune suppression and promotes pathogenic subretinal inflammation and can be therapeutically countered by local recombinant TSP-

Profil d’expression des médiateurs d’inflammation dans le vitré des patients présentant un décollement de rétine rhegmatogène

International audiencePurpose: To compare the expression profiles of various cytokines and chemokines in vitreous samples from patients with retinal detachment (RD) to those from controls and to analyze their association with various clinical features.Methods: In this prospective study, undiluted vitreous fluid was obtained from 41 patients with primary RD and 33 controls with macular hole or vitreomacular traction. A multiplex bead immunoassay was performed to determine the expression of 27 inflammatory mediators.Results: Eleven mediators were significantly upregulated in the vitreous of RD patients compared with controls, including the following: cytokines IL-1ra, IL-6, IL-7, IL-8, IFN-γ; chemokines CCL2, CCL3, CCL4, CXCL10 and CCL11 and growth factor G-CSF. Correlation analyses showed that levels of IL-1ra, CXCL10, CCL11 and G-CSF were positively correlated to the extent of detachment, while those of IL-1ra and CXCL10 were associated with the duration of detachment. There was also a positive association between the concentrations of CXCL10 and CCL11 and preoperative flare values. Additional analysis revealed that flare values and both CXCL10 and CCL11 levels were significantly higher in eyes with grade B or C proliferative vitreoretinopathy (PVR).Conclusion: Our results confirm that RD induces a marked inflammatory response with a complex cytokine network. We identified proteins specifically linked to several clinical features that might contribute to photoreceptor degeneration and PVR-related redetachment. These proteins may represent potential therapeutic targets for improving the anatomical and functional outcomes of RD surgery.But: Évaluer le profil des médiateurs d’inflammation dans le vitré des patients présentant un décollement de rétine (DR) rhegmatogène et corréler leur expression avec différents paramètres cliniques.Matériel et méthode: Etude prospective portant sur 74 patients ayant bénéficié d’un prélèvement vitréen lors d’une vitrectomie pour un DR primaire (n = 41) ou un trou maculaire idiopathique (n = 33, témoins). Les échantillons de vitré ont été analysés selon une technique Luminex® visant à quantifier l’expression de 27 médiateurs inflammatoires.Résultats: Onze médiateurs était significativement surexprimés dans le vitré des patients opérés de DR : les cytokines IL-1ra, IL-6, IL-7, IL-8, IFN-γ; les chimiokines CCL2, CCL3, CCL4, CXCL10 et CCL11 et le facteur de croissance G-CSF. Les analyses de corrélation ont montré que les taux d’IL-1ra, CXCL10, CCL11 et G-CSF étaient corrélés à l’étendue du DR tandis que ceux d’ IL-1ra et CXCL10 étaient associés à la durée du DR. Il existait également une forte association entre les concentrations de CXCL10 et CCL11 et le flare de l’humeur aqueuse en préopératoire. Les valeurs de flare et les taux de CXCL10 et CCL11 étaient par ailleurs significativement plus élevés dans les yeux avec prolifération vitréo-rétinienne (PVR) de stade B ou C.Conclusion:Nos résultats confirment que le DR induit une réponse inflammatoire sévère impliquant un réseau complexe de cytokines. Nous avons identifié plusieurs protéines spécifiquement associées à différents paramètres cliniques, susceptibles de contribuer à la dégénérescence des photorécepteurs et au développement de la PVR. Elles pourraient représenter des cibles thérapeutiques potentielles pour améliorer les résultats anatomiques et fonctionnels de la chirurgie du D

STAR: a randomized controlled trial for submacular hemorrhage secondary to age-related macular degeneration

Meeting presentations: Oral presentation at the American Academy of Ophthalmology Annual Meeting, 2022International audienceOBJECTIVE: To compare the efficacy and the safety of submacular hemorrhage (SMH) management with either surgical pars plana vitrectomy (PPV) or pneumatic displacement (PD), with tissue plasminogen activator (TPA) and vascular endothelial growth factor (VEGF) inhibitor added to each arm. DESIGN: Randomized, open-label, multicenter superiority study. PARTICIPANTS: Ninety patients with neovascular age-related macular degeneration (nAMD) aged ≥50 years, with recent SMH (≤14 days) greater than 2 optic disk areas and predominantly overlying the retinal pigment epithelium. INTERVENTIONS: Patients were randomly assigned to surgery (PPV, subretinal TPA [max 0.5 ml/50 μg], and 20% sulfahexafluoride [SF6] tamponade) or PD (0.05 ml intravitreal TPA [50 μg] and 0.3 ml intravitreal pure SF6). Both groups were asked to maintain a head upright position with the face forward at 45° for 3 days after intervention and received 0.5 mg intravitreal ranibizumab at the end of the intervention, at Month 1 and 2, as the loading phase, and then on a pro re nata regimen during a 6-month follow-up. METHODS AND OUTCOME MEASURES: The primary efficacy endpoint was mean best-corrected visual acuity (VA) change at Month 3. The secondary endpoints were mean VA change at Month 6, National Eye Institute 25-item Visual Function Questionnaire (VFQ-25) composite score value at Month 3 and 6, number of anti-VEGF injections, and complications during the 6-month follow-up. RESULTS: Of the 90 patients randomized, 78 (86.7%) completed the 3-month efficacy endpoint visit. The mean±SD age was 83.3±8.2 years, and 66.3% were female. The mean duration of symptoms before treatment was 7.5±4.4 days. The mean VA change from baseline to Month 3 in the surgery group (+16.8 letters, [95% CI, 8.7; 24.9]) was not significantly superior to the PD group (+16.4 letters, [95% CI, 7.1;25.7]; adjusted difference β, -1.9 [95% CI, -14.9;11.0], P = 0.767). Both groups achieved similar secondary outcomes at Month 6. No unexpected ocular safety concerns were observed in either group. CONCLUSIONS: Surgery did not yield superior visual gain nor additional benefit for SMH secondary to nAMD compared to PD at 3 months, with intravitreal anti-VEGF added to each arm. Both treatment strategies lead to a clinical improvement of visual acuity without safety concerns for SMH over 6 months. Both design and results of the trial cannot be used to establish equivalence between treatments

A transgenic mice model of retinopathy of cblG-type inherited disorder of one-carbon metabolism highlights epigenome-wide alterations related to cone photoreceptor cells development and retinal metabolism

Abstract Background MTR gene encodes the cytoplasmic enzyme methionine synthase, which plays a pivotal role in the methionine cycle of one-carbon metabolism. This cycle holds a significant importance in generating S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), the respective universal methyl donor and end-product of epigenetic transmethylation reactions. cblG type of inherited disorders of vitamin B12 metabolism due to mutations in MTR gene exhibits a wide spectrum of symptoms, including a retinopathy unresponsive to conventional therapies. Methods To unveil the underlying epigenetic pathological mechanisms, we conducted a comprehensive study of epigenomic-wide alterations of DNA methylation by NGS of bisulfited retinal DNA in an original murine model with conditional Mtr deletion in retinal tissue. Our focus was on postnatal day 21, a critical developmental juncture for ocular structure refinement and functional maturation. Results We observed delayed eye opening and impaired visual acuity and alterations in the one-carbon metabolomic profile, with a notable dramatic decline in SAM/SAH ratio predicted to impair DNA methylation. This metabolic disruption led to epigenome-wide changes in genes involved in eye development, synaptic plasticity, and retinoid metabolism, including promoter hypermethylation of Rarα, a regulator of Lrat expression. Consistently, we observed a decline in cone photoreceptor cells and reduced expression of Lrat, Rpe65, and Rdh5, three pivotal genes of eye retinoid metabolism. Conclusion We introduced an original in vivo model for studying cblG retinopathy, which highlighted the pivotal role of altered DNA methylation in eye development, cone differentiation, and retinoid metabolism. This model can be used for preclinical studies of novel therapeutic targets

Insulin inhibits inflammation-induced cone death in retinal detachment

International audienceRhegmatogenous retinal detachment (RD) involving the macula is a major cause of visual impairment despite high surgical success rate, mainly because of cone death. RD causes the infiltration of activated immune cells, but it is not clear whether and how infiltrating inflammatory cells contribute to cone cell loss.MethodsVitreous samples from patients with RD and from control patients with macular hole were analyzed to characterize the inflammatory response to RD. A mouse model of RD and retinal explants culture were then used to explore the mechanisms leading to cone death.ResultsAnalysis of vitreous samples confirms that RD induces a marked inflammatory response with increased cytokine and chemokine expression in humans, which is closely mimicked by experimental murine RD. In this model, we corroborate that myeloid cells and T-lymphocytes contribute to cone loss, as the inhibition of their accumulation by Thrombospondin 1 (TSP1) increased cone survival. Using monocyte/retinal co-cultures and TSP1 treatment in RD, we demonstrate that immune cell infiltration downregulates rod-derived cone viability factor (RdCVF), which physiologically regulates glucose uptake in cones. Insulin and the insulin sensitizers rosiglitazone and metformin prevent in part the RD-induced cone loss in vivo, despite the persistence of inflammationConclusionOur results describe a new mechanism by which inflammation induces cone death in RD, likely through cone starvation due to the downregulation of RdCVF that could be reversed by insulin. Therapeutic inhibition of inflammation and stimulation of glucose availability in cones by insulin signaling might prevent RD-associated cone death until the RD can be surgically repaired and improve visual outcome after RD

Characterization and Transplantation of CD73-Positive Photoreceptors Isolated from Human iPSC-Derived Retinal Organoids

International audienc

Lebecetin, a C-type lectin, inhibits choroidal and retinal neovascularization

International audienceAngiogenesis is a cause of visual impairment and blindness in the wet form of age-related macular degeneration and in ischemic retinopathies. Current therapies include use of anti-VEGF agents to reduce choroidal neovascularization (CNV) and edema. These treatments are effective in most cases, but spontaneous or acquired resistance to anti-VEGF and possible adverse effects of long-term VEGF inhibition in the retina and choroid highlight a need for additional alternative therapies. Integrins alpha v beta 3 and alpha v beta 5, which regulate endothelial cell proliferation and stabilization, have been implicated in ocular angiogenesis. Lebecetin (LCT) is a 30-kDa heterodimeric C-type lectin that is isolated from Macrovipera lebetina venom and interacts with alpha 5 beta 1-and alpha v-containing integrins. We previously showed that LCT inhibits human brain microvascular endothelial cell adhesion, migration, proliferation, and tubulogenesis. To evaluate the inhibitory effect of LCT on ocular angiogenesis, we cultured aortic and choroidal explants in the presence of LCT and analyzed the effect of LCT on CNV in the mouse CNV model and on retinal neovascularization in the oxygen-induced retinopathy model. Our data demonstrate that a single injection of LCT efficiently reduced CNV and retinal neovascularization in these models