Scleromyxedema associated with macular edema and retinal hemorrhage.

PURPOSE: We discuss a case of macular edema and retinal hemorrhage associated with scleromyxedema. METHODS: A case report is presented. RESULTS: A 64-year-old male with history of deep vein thrombosis and pulmonary embolism presented with new onset rash in the setting of switching anticoagulation treatments. He developed blurred vision was found to have macular edema and dot blot retinal hemorrhages which improved with systemic and topical corticosteroids. CONCLUSIONS: Systemic autoimmune conditions including scleromyxedema should be considered in the workup of occult cystoid macular edema.

Erythropoiesis-Stimulating Agents and the Risk of Vision-Threatening Diabetic Retinopathy.

PURPOSE: Animal studies have suggested that Erythropoiesis-Stimulating Agents (ESAs) may increase vascular endothelial growth factor (VEGF)-related retinopathies, but this effect is unclear in humans. This study evaluates the risk of vision-threatening diabetic retinopathy (VTDR), defined as either diabetic macular edema (DME) or proliferative diabetic retinopathy (PDR), in patients exposed to an ESA. METHODS: Two analyses were performed. First, a retrospective matched-cohort study was designed using a de-identified commercial and Medicare Advantage medical claims database. The ESA cohort of non-proliferative diabetic retinopathy patients who were new users of an ESA from 2000 to 2022 was matched to controls up to a 3:1 ratio. Exclusion criteria included less than 2 years in the plan, history of VTDR or history of other retinopathy. Multivariable Cox proportional hazards regression with inverse proportional treatment weighting (IPTW) was used to assess the hazard of developing VTDR, DME, and PDR. The second analysis was a self-controlled case series (SCCS) evaluating the incidence rate ratios (IRR) of VTDR during 30-day periods before and after initiating an ESA. RESULTS: After inclusion of 1502 ESA-exposed patients compared with 2656 controls, IPTW-adjusted hazard ratios found the ESA cohort had an increased hazard of progressing to VTDR (HR = 3.0 95%CI:2.3-3.8;p < .001) and DME (HR = 3.4,95%CI:2.6-4.4,p < .001), but not PDR (HR = 1.0,95%CI:0.5-2.3,p = .95). Similar results were found within the SCCS which demonstrated higher IRRs for VTDR (IRRs = 1.09-1.18;p < .001) and DME (IRRs = 1.16-1.18;p < .001), but not increased IRRs in PDR (IRR = 0.92-0.97,p = .02-0.39). CONCLUSION: ESAs are associated with higher risks for VTDR and DME, but not PDR. Those studying ESAs as adjunctive therapy for DR should be cautious of possible unintended effects.

Restoration of Vision and Retinal Responses After Adeno-Associated Virus-Mediated Optogenetic Therapy in Blind Dogs.

Purpose: Optogenetic gene therapy to render remaining retinal cells light-sensitive in end-stage retinal degeneration is a promising strategy for treatment of individuals blind because of a variety of different inherited retinal degenerations. The clinical trials currently in progress focus on delivery of optogenetic genes to ganglion cells. Delivery of optogenetic molecules to cells in the outer neural retina is predicted to be even more advantageous because it harnesses more of the retinal circuitry. However, this approach has not yet been tested in large animal models. For this reason, we evaluated the safety and efficacy of optogenetic therapy targeting remaining diseased cone photoreceptors in the Rcd1 dog model of retinitis pigmentosa. Methods: Imaging and measures of retinal function and functional vision were carried out, as well as terminal studies evaluating multi-electrode array recordings and histology. Results: Animals remained healthy and active throughout the study and showed improved retinal and visual function as assessed by electroretinography and visual-evoked potentials, improved navigational vision, and improved function of cone photoreceptors and the downstream retinal circuitry. Conclusions: The findings demonstrate that an optogenetic approach targeting the outer retina in a blind large animal model can partially restore vision. Translational Relevance: This work has translational relevance because the approach could potentially be extrapolated to treat humans who are totally blind because of retinal degenerative disease.

Cryptococcus gattii endogenous chorioretinitis.

PURPOSE: To present a case of subretinal abscess associated with pneumonia and meningitis caused by Cryptococcus gattii in an immunocompetent host. OBSERVATIONS: A 37-year-old man presented with sub-acute painless unilateral vision loss and a white submacular elevation. Systemic evaluation revealed a lung lesion and cerebrospinal fluid evidence of Cryptococcus gattii infection. CONCLUSIONS AND IMPORTANCE: While Crypococcus neoformans has been well described as a cause of chorioretinitis in immunocompetent and immunocompromised hosts, this report demonstrates that Cryptocuccus gattii is a related uncommon pathogen to be considered in similar presentations. Submacular surgical debridement may be challenging and OCT imaging may be helpful to detect full-thickness retinal necrosis.

Neuroprotection mediated by ST266 requires full complement of proteins secreted by amnion-derived multipotent progenitor cells.

ST266 is the biological secretome of cultured Amnion-derived Multipotent Progenitor cells containing multiple growth factors and cytokines. While intranasally-administered ST266 improves the phenotype in experimental optic neuritis, specific ST266 components mediating these effects are not known. We compared the effects of ST266 with and without removal of large molecular weight proteins both in vitro and in the multiple sclerosis model experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice. Mice were treated daily with intranasal vehicle, ST266 or lower molecular weight fraction of ST266. Retinal ganglion cells were counted in isolated retinas, and optic nerves were assessed for inflammation and demyelination. ST266 treatment significantly improved retinal ganglion cell survival and reduced optic nerve demyelination in EAE mice. The lower molecular weight ST266 fraction significantly improved optic nerve demyelination, but only showed a trend towards improved retinal ganglion cell survival. ST266 fractions below 50kDa increased Schwann cell proliferation in vitro, but were less effective than non-fractionated ST266. Demyelination attenuation was partially associated with the lower molecular weight ST266 fraction, but removal of higher molecular weight biomolecules from ST266 diminishes its neuroprotective effects, suggesting at least some high molecular weight proteins play a role in ST266-mediated neuroprotection.

Amnion-Derived Multipotent Progenitor Cells Suppress Experimental Optic Neuritis and Myelitis.

The human amnion has been used for decades in wound healing, particularly burns. Amnion epithelial cells (AECs) have been the focus of extensive research based on their possible pluripotent differentiation ability. A novel, cultured cell population derived from AECs, termed human amnion-derived multipotent progenitor (AMP) cells, secrete numerous cytokines and growth factors that enhance tissue regeneration and reduce inflammation. This AMP cell secretome, termed ST266, is a unique biological solution that accumulates in eyes and optic nerves following intranasal delivery, resulting in selective suppression of optic neuritis in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, but not myelitis at the administered dose. We tested the hypothesis that systemic AMP cell administration could suppress both optic neuritis and myelitis in EAE. Intravenous and intraperitoneal administration of AMP cells significantly reduced ascending paralysis and attenuated visual dysfunction in EAE mice. AMP cell treatment increased retinal ganglion cell (RGC) survival and decreased optic nerve inflammation, with variable improvement in optic nerve demyelination and spinal cord inflammation and demyelination. Results show systemic AMP cell administration inhibits RGC loss and visual dysfunction similar to previously demonstrated effects of intranasally delivered ST266. Importantly, AMP cells also promote neuroprotective effects in EAE spinal cords, marked by reduced paralysis. Protective effects of systemically administered AMP cells suggest they may serve as a potential novel treatment for multiple sclerosis.

Quality of CT Imaging of Periocular Metallic Foreign Bodies Using Artifact Reduction Software.

PURPOSE: CT is the standard of care for assessment of ocular and orbital trauma; however, artifacts from metallic foreign bodies can limit the utility of CT. The authors hypothesize that implementation of metal artifact reduction techniques can improve image quality and diagnostic confidence for a diverse group of interpreters. METHODS: A case series of ten subjects with retained periocular metallic foreign bodies imaged with CT were identified retrospectively from a large urban trauma center. Postacquisition images were processed with an iterative-based metal streak artifact reduction software. The severity of the metal streak artifact was assessed by clinicians including radiologists (4), ophthalmologists (4), and oculoplastic specialists (3) using a numeric scale to grade images on seven clinically relevant criteria. Each image was also analyzed to measure the size of the artifact and degree of streaking. RESULTS: Overall confidence in diagnosis and severity of metallic streak was improved with metallic artifact reduction (p < 0.001, Wilcoxon signed-rank test). Similarly, confidence in assessing specific features-including extra-ocular muscle, optic nerve, globe rupture, orbital fracture and identification of foreign bodies-was improved after metallic artifact reduction (p < 0.001, Wilcoxon signed-rank test). The standard deviation of pixel intensity for a path surrounding the foreign body as well as the area of the streak artifact decreased in the metallic artifact reduction-processed images (p < 0.001, paired t test). CONCLUSIONS: Metal artifact reduction in CT has potential benefits in improving image quality and reader confidence for periocular trauma cases in real-world settings.

Evaluation of Dose and Safety of AAV7m8 and AAV8BP2 in the Non-Human Primate Retina.

Within the next decade, we will see many gene therapy clinical trials for eye diseases, which may lead to treatments for thousands of visually impaired people around the world. To target retinal diseases that affect specific cell types, several recombinant adeno-associated virus (AAV) serotypes have been generated and used successfully in preclinical mouse studies. Because there are numerous anatomic and physiologic differences between the eyes of mice and "men" and because surgical delivery approaches and immunologic responses also differ between these species, this study evaluated the transduction characteristics of two promising new serotypes, AAV7m8 and AAV8BP2, in the retinas of animals that are most similar to those of humans: non-human primates (NHPs). We report that while AAV7m8 efficiently targets a variety of cell types by subretinal injection in NHPs, transduction after intravitreal delivery was mostly restricted to the inner retina at lower doses that did not induce an immune response. AAV8BP2 targets the cone photoreceptors efficiently but bipolar cells inefficiently by subretinal injection. Additionally, transduction by both serotypes in the anterior chamber of the eye and the optic pathway of the brain was observed post-intravitreal delivery. Finally, we assessed immunogenicity, keeping in mind that these AAV capsids may be used in future clinical trials. We found that AAV8BP2 had a better safety profile compared with AAV7m8, even at the highest doses administered. These studies underscore the differences in AAV transduction between mice and primates, highlighting the importance of careful evaluation of therapeutic vectors in NHPs prior to moving to clinical trials.

Immunology of AAV-Mediated Gene Transfer in the Eye.

The eye has been at the forefront of translational gene therapy largely owing to suitable disease targets, anatomic accessibility, and well-studied immunologic privilege. These advantages have fostered research culminating in several clinical trials and adeno-associated virus (AAV) has emerged as the vector of choice for many ocular therapies. Pre-clinical and clinical investigations have assessed the humoral and cellular immune responses to a variety of naturally occurring and engineered AAV serotypes as well as their delivered transgenes and these data have been correlated to potential clinical sequelae. Encouragingly, AAV appears safe and effective with clinical follow-up surpassing 5 years in some studies. As disease targets continue to expand for AAV in the eye, thorough and deliberate assessment of immunologic safety is critical. With careful study, the development of these technologies should concurrently inform the biology of the ocular immune response.

Retinal expression of Wnt-pathway mediated genes in low-density lipoprotein receptor-related protein 5 (Lrp5) knockout mice.

Mutations in low-density lipoprotein receptor-related protein 5 (Lrp5) impair retinal angiogenesis in patients with familial exudative vitreoretinopathy (FEVR), a rare type of blinding vascular eye disease. The defective retinal vasculature phenotype in human FEVR patients is recapitulated in Lrp5 knockout (Lrp5(-/-)) mouse with delayed and incomplete development of retinal vessels. In this study we examined gene expression changes in the developing Lrp5(-/-) mouse retina to gain insight into the molecular mechanisms that underlie the pathology of FEVR in humans. Gene expression levels were assessed with an Illumina microarray on total RNA from Lrp5(-/-) and WT retinas isolated on postnatal day (P) 8. Regulated genes were confirmed using RT-qPCR analysis. Consistent with a role in vascular development, we identified expression changes in genes involved in cell-cell adhesion, blood vessel morphogenesis and membrane transport in Lrp5(-/-) retina compared to WT retina. In particular, tight junction protein claudin5 and amino acid transporter slc38a5 are both highly down-regulated in Lrp5(-/-) retina. Similarly, several Wnt ligands including Wnt7b show decreased expression levels. Plasmalemma vesicle associated protein (plvap), an endothelial permeability marker, in contrast, is up-regulated consistent with increased permeability in Lrp5(-/-) retinas. Together these data suggest that Lrp5 regulates multiple groups of genes that influence retinal angiogenesis and may contribute to the pathogenesis of FEVR.

Wnt signaling mediates pathological vascular growth in proliferative retinopathy.

BACKGROUND: Ischemic proliferative retinopathy, characterized by pathological retinal neovascularization, is a major cause of blindness in working-age adults and children. Defining the molecular pathways distinguishing pathological neovascularization from normal vessels is critical to controlling these blinding diseases with targeted therapy. Because mutations in Wnt signaling cause defective retinal vasculature in humans with some characteristics of the pathological vessels in retinopathy, we investigated the potential role of Wnt signaling in pathological retinal vascular growth in proliferative retinopathy. METHODS AND RESULTS: In this study, we show that Wnt receptors (Frizzled4 and low-density lipoprotein receptor-related protein5 [Lrp5]) and activity are significantly increased in pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Loss of Wnt coreceptor Lrp5 and downstream signaling molecule dishevelled2 significantly decreases the formation of pathological retinal neovascularization in retinopathy. Loss of Lrp5 also affects retinal angiogenesis during development and formation of the blood-retinal barrier, which is linked to significant downregulation of tight junction protein claudin5 in Lrp5(-/-) vessels. Blocking claudin5 significantly suppresses Wnt pathway-driven endothelial cell sprouting in vitro and developmental and pathological vascular growth in retinopathy in vivo. CONCLUSIONS: These results demonstrate an important role of Wnt signaling in pathological vascular development in retinopathy and show a novel function of Cln5 in promoting angiogenesis.

5-Lipoxygenase metabolite 4-HDHA is a mediator of the antiangiogenic effect of ω-3 polyunsaturated fatty acids.

Lipid signaling is dysregulated in many diseases with vascular pathology, including cancer, diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration. We have previously demonstrated that diets enriched in ω-3 polyunsaturated fatty acids (PUFAs) effectively reduce pathological retinal neovascularization in a mouse model of oxygen-induced retinopathy, in part through metabolic products that suppress microglial-derived tumor necrosis factor-α. To better understand the protective effects of ω-3 PUFAs, we examined the relative importance of major lipid metabolic pathways and their products in contributing to this effect. ω-3 PUFA diets were fed to four lines of mice deficient in each key lipid-processing enzyme (cyclooxygenase 1 or 2, or lipoxygenase 5 or 12/15), retinopathy was induced by oxygen exposure; only loss of 5-lipoxygenase (5-LOX) abrogated the protection against retinopathy of dietary ω-3 PUFAs. This protective effect was due to 5-LOX oxidation of the ω-3 PUFA lipid docosahexaenoic acid to 4-hydroxy-docosahexaenoic acid (4-HDHA). 4-HDHA directly inhibited endothelial cell proliferation and sprouting angiogenesis via peroxisome proliferator-activated receptor γ (PPARγ), independent of 4-HDHA's anti-inflammatory effects. Our study suggests that ω-3 PUFAs may be profitably used as an alternative or supplement to current anti-vascular endothelial growth factor (VEGF) treatment for proliferative retinopathy and points to the therapeutic potential of ω-3 PUFAs and metabolites in other diseases of vasoproliferation. It also suggests that cyclooxygenase inhibitors such as aspirin and ibuprofen (but not lipoxygenase inhibitors such as zileuton) might be used without losing the beneficial effect of dietary ω-3 PUFA.

Proliferative retinopathy is associated with impaired increase in BDNF and RANTES expression levels after preterm birth.

BACKGROUND: Extremely preterm delivery is, amongst other complications, associated with retinopathy of prematurity (ROP). Untreated, ROP can progress to visual impairment and blindness due to an overgrowth of new vessels in the retina and vitreous cavity. OBJECTIVE: The aim of this study was to identify cytokine markers within the first weeks of life that could be used to predict the risk for development of ROP later in life. METHODS: Serum levels of 27 different cytokines in infants born at gestational weeks 23-30 were analyzed using a multiplex immunoassay method and compared between infants who did not develop ROP and infants who later developed proliferative ROP. In addition, mRNA levels of brain-derived neurotrophic factor (BDNF) in retinas from mice exposed to hyperoxia were analyzed using quantitative real-time PCR. RESULTS: At birth, serum levels of IL-5 were higher in infants with no ROP compared to infants with proliferative ROP. 10-14 days after birth, serum levels of BDNF and RANTES were lower in infants who later developed proliferative ROP compared to infants who did not develop ROP. Furthermore, mRNA expression levels of BDNF in retinas from mice exposed to hyperoxia were significantly lower at postnatal day 15 compared to retinas from mice in room air. CONCLUSIONS: These results indicate that BDNF and RANTES may be important factors in the selective vulnerability of ROP development in preterm infants.

Short communication: PPAR gamma mediates a direct antiangiogenic effect of omega 3-PUFAs in proliferative retinopathy.

RATIONALE: Omega3 long-chain polyunsaturated fatty acids (omega3-PUFAs) are powerful modulators of angiogenesis. However, little is known about the mechanisms governing omega3-PUFA-dependent attenuation of angiogenesis. OBJECTIVE: This study aims to identify a major mechanism by which omega3-PUFAs attenuate retinal neovascularization. METHODS AND RESULTS: Administering omega3-PUFAs exclusively during the neovascular stage of the mouse model of oxygen-induced retinopathy induces a direct neovascularization reduction of more than 40% without altering vasoobliteration or the regrowth of normal vessels. Cotreatment with an inhibitor of peroxisome proliferator-activated receptor (PPAR)gamma almost completely abrogates this effect. Inhibition of PPARgamma also reverses the omega3-PUFA-induced reduction of retinal tumor necrosis factor-alpha, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial selectin, and angiopoietin 2 but not vascular endothelial growth factor. CONCLUSIONS: These results identify a direct, PPARgamma-mediated effect of omega3-PUFAs on retinal neovascularization formation and retinal angiogenic activation that is independent of vascular endothelial growth factor.

The mouse retina as an angiogenesis model.

The mouse retina has been used extensively over the past decades to study both physiologic and pathologic angiogenesis. Over time, various mouse retina models have evolved into well-characterized and robust tools for in vivo angiogenesis research. This article is a review of the angiogenic development of the mouse retina and a discussion of some of the most widely used vascular disease models. From the multitude of studies performed in the mouse retina, a selection of representative works is discussed in more detail regarding their role in advancing the understanding of both the ocular and general mechanisms of angiogenesis.

Quantification of oxygen-induced retinopathy in the mouse: a model of vessel loss, vessel regrowth and pathological angiogenesis.

The mouse model of oxygen-induced retinopathy (OIR) has been widely used in studies related to retinopathy of prematurity, proliferative diabetic retinopathy and in studies evaluating the efficacy of antiangiogenic compounds. In this model, 7-d-old (P7) mouse pups with nursing mothers are subjected to hyperoxia (75% oxygen) for 5 d, which inhibits retinal vessel growth and causes significant vessel loss. On P12, mice are returned to room air and the hypoxic avascular retina triggers both normal vessel regrowth and retinal neovascularization (NV), which is maximal at P17. Neovascularization spontaneously regresses between P17 and P25. Although the OIR model has been the cornerstone of studies investigating proliferative retinopathies, there is currently no harmonized protocol to assess aspects of angiogenesis and treatment outcome. In this protocol we describe standards for mouse size, sample size, retinal preparation, quantification of vascular loss, vascular regrowth, NV and neovascular regression.

Suppression of retinal neovascularization by erythropoietin siRNA in a mouse model of proliferative retinopathy.

PURPOSE: Erythropoietin (EPO), an oxygen-regulated hormone stimulating erythrocyte production, was recently found to be critical for retinal angiogenesis. EPO mRNA expression levels in retina are highly elevated during the hypoxia-induced proliferation phase of retinopathy. The authors investigated the inhibition of retinal EPO mRNA expression with RNA interference as a potential strategy to suppress retinal neovascularization and to prevent proliferative retinopathy. METHODS: The authors used a mouse model of oxygen-induced retinopathy. Retinal EPO and Epo receptor (EpoR) expression during retinopathy development were quantified with real-time RT-PCR in whole retina and on laser-captured retinal vessels and neuronal layers. Retinal hypoxia was assessed with an oxygen-sensitive hypoxyprobe. A small interference RNA (siRNA) targeting EPO or control negative siRNA was injected intravitreally at postnatal (P) day 12, P14, and P15 during the hypoxic phase, and the effect on neovascularization was evaluated in retinal flatmounts at P17. RESULTS: Retinal EPO mRNA expression in total retina was suppressed during the initial phase of vessel loss in retinopathy and was significantly elevated during the hypoxia-induced proliferative phase in all three neuronal layers in the retina, corresponding to an increased level of retinal hypoxia. EpoR mRNA expression levels also increased during the second neovascular phase, specifically in hypoxia-induced neovascular vessels. Intravitreous injection of EPO siRNA effectively inhibited approximately 60% of retinal EPO mRNA expression and significantly suppressed retinal neovascularization by approximately 40%. CONCLUSIONS: Inhibiting EPO mRNA expression with siRNA is effective in suppressing retinal neovascularization, suggesting EPO siRNA is a potentially useful pharmaceutical intervention for treating proliferative retinopathy.

Quantification and localization of the IGF/insulin system expression in retinal blood vessels and neurons during oxygen-induced retinopathy in mice.

PURPOSE: Retinopathy is a result of pathologic angiogenesis influenced by insulinlike growth factor (IGF)-1. The authors examined the local expression of the IGF/insulin family. METHODS: In retinas with and without oxygen-induced retinopathy, the authors assessed with real-time RT-PCR mRNA expression of the IGF-1 receptor (IGF-1R), insulin receptor (IR), IGF-1, IGF-2, insulin (Ins2), and IGF-binding protein 1 (IGFBP1) to IGFBP6 in total retina from postnatal day (P) 7 to P33 to examine changes over time with the induction of retinopathy and at P17 on laser-captured retinal components to quantitatively localize mRNA expression in the ganglion cell layer, the outer nuclear layer, the inner nuclear layer, normal blood vessels, and neovascular tufts. RESULTS: IGF-1R and IR are expressed predominantly in photoreceptors and in vessels, with scant expression in the rest of the neural retina. IGF-1R expression is more than 100-fold greater than IR. The major local growth factor (expressed in photoreceptors and in blood vessels) is IGF-2 (approximately 1000-fold greater than IGF-1). IGF-1 (approximately 600 copies/10(6) cyclophilin) is expressed throughout the retina. IGFBP2, IGFBP4, and IGFBP5 expression is unchanged with increasing retinal development and with the induction of retinopathy. In contrast, IGFBP3 expression increased more than 5-fold with hypoxia, found in neovascular tufts. CONCLUSIONS: IGF-1R, IR, and the ligand IGF-2 are expressed almost exclusively in photoreceptors and blood vessels. IGFBP3 and IGFBP5 expression increases in neovascular tufts compared with normal vessels. IGF-1 is expressed throughout the retina at much lower levels. These results suggest cross-talk between vessels and photoreceptors in the development of retinopathy and retinal vasculature.