A food-grade arabinoxylan/caseinate hydrogel for sustained delivery of cyanidin-3-glucoside: Temporal optimization of cytoprotection against blue light-induced retinal epithelium injury.

Extrinsic polarity cues control lamination versus cluster-based organization in vertebrate retinal development.

Age-related macular degeneration (AMD) is the leading cause of visual impairment among older adults in developed countries. It results from the accumulation of drusen deposits and changes in the retinal pigmentary epithelium (RPE), leading to progressive, painless central vision loss. The severity of AMD can vary, and those affected often do not experience noticeable symptoms until the disease is well advanced. Early symptoms may include visual distortion or flickering lights, and, in more advanced stages, central vision loss. In primary care, assessment should involve a thorough history and examination including assessment of visual acuity and ophthalmoscopy. Individuals suspected of having neovascular AMD should be promptly assessed and referred to secondary care for consideration of specialist interventions.

ObjectiveThis study was conducted to determine and compare the antioxidant, cytotoxic, and antimicrobial effects of spindle leaves of Elaeagnus angustifolia L. (E. angustifolia) (oleaster) leaves.MethodsTotal phenolic content was measured using the Folin-Ciocalteu method, phenolic compound analysis by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and antimicrobial effect by the minimum inhibition concentration (MIC) method. The free radical scavenging activity was determined by the (2,2-Diphenyl-1-picrylhydrazyl) DPPH method, the free radical scavenging activity was determined by the ABTS method, and cytotoxicity assays were performed by the MTT method in human retinal epithelium cells (RPE-1), human osteosarcoma cells (U2OS), and prostate cancer cells (DU-145) cell lines.ResultsHigh amounts of gallic acid, protocatechuic acid, and o-coumaric acid were identified as phenolic compounds. E. angustifolia was found to have a good antioxidant capacity and high free radical scavenging capacity. In this study, for the first time, E. angustifolia leaf extract was used to investigate cytotoxic effects on human retinal epithelium (RPE-1), human osteosarcoma cells (U2OS), and prostate cancer (DU-145) cells and antimicrobial effects on Listeria monocytogenes American Type Culture Collection (ATTC) 7644, Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, Klebsiella pneumonia ATCC 11774, and Candida albicans ATCC 10231 microorganisms. The highest cytotoxic effect was observed in the DU-145 cell line, and the highest antimicrobial effect was observed in Listeria monocytogenes ATTC 7644 and Candida albicans ATCC 10231. The leaf extract of the plant contains some important phenolic compounds and has high free radical scavenging capacity, a good anticancer effect, and effective antimicrobial activity on yeast species such as C. albicans.ConclusionOur study will contribute greatly to the search for anticancer and antimicrobial agents, especially from a pharmacological perspective, by examining biological activity using three different methods.

Ischemic and/or hypoxic ocular diseases lack adequate, effective mitigative approaches and an understanding of the fundamental causes of ischemia-induced tissue damage. In this work, we introduce a plant-derived exosome-coated niosome oxygen nanobubble (E-NON), consisting of a gaseous oxygen core encapsulated within dual shells. The niosome inner shell is composed of Pluronic F-127, polysorbate 80, and medium chain triglyceride (MCT) oil, all of which are FDA approved for ophthalmic indications. The outer shell consists of exosomes derived from (ashwagandha) fruits, which are known for their antioxidant and anti-inflammatory properties. The hydrodynamic diameter of conceived E-NONs is 85.6 ± 14.4 nm with a zeta (ζ)-potential of -19.3 ± 0.8 mV, and oxygen loading capacity of 56.4 ± 0.9 mg/L. The E-NON formulation was stable in sealed glass vials for up to 3 months at 4 °C and yields a controlled release profile extending up to 16 h under hypoxic conditions. The therapeutic efficacy of E-NONs for hypoxia mitigation was evaluated in retinal epithelium (ARPE19) and uveal melanoma (MP46) cell lines, both demonstrating excellent hypoxia recovery. Moreover, RT-qPCR results verified downregulation of genes related to hypoxia (HIF-1α, VEGF-A, EPO, PAI-1) and oxidative stress (Nrf2, NQO1, HO-1) after treatment with 10 (v/v%) E-NONs. Additionally, an in vivo safety evaluation in a rabbit model indicated that the formulation was safe for intravitreal administration. We propose that our novel oxygen delivery platform is an effective tool for hypoxia mitigation and can be utilized to treat ischemic conditions in the eye.

During development, tissues undergo morphogenesis to achieve their final form. This process relies on coordinated cell shape changes, which have predominantly been studied in one plane, at the apical (top) surface of developing tissues. However, tissues are three dimensional, often exhibiting deformations along multiple axes. To understand how morphogenesis is coordinated across tissue axes, we used the genetically amenable Drosophila retina, a curved, dome-shaped epithelium, as a model system. Using intravital imaging, we found that retinal curvature is induced early in development. Modeling early retinal development with a vertex model suggests that this curvature arises from differential planar growth between the apical and basal tissue surfaces. In addition, mechanical perturbation experiments revealed that inside-out fluid pressure plays a crucial role in promoting this curvature. Further combining computational modeling, genetic perturbations, and force-inference experiments, we demonstrate that uniform thickening of the curved retinal epithelium requires coordination of two key processes: growth, promoting cell elongation along the apical-basal axis of the tissue, and basal surface contraction. Remarkably, inhibiting basal surface contraction-both in silico and through genetic manipulations targeting the basal surface receptor integrin and non-muscle myosin-II-prevented cell elongation. We conclude that thickening of a curved epithelium, like the Drosophila retina, requires both integrin and non-muscle myosin-II to coordinate basal surface contraction and cell growth along the apical-basal axis of the tissue.

Retinal detachment (RD) separates the retina from the retinal epithelium, causing photoreceptor apoptosis and irreversible vision loss. Even with successful surgical reattachment, complete visual recovery is not guaranteed. The TP53 Arg72Pro polymorphism, implicated in apoptosis, has emerged as a potential predictor of RD outcomes. We investigated the impact of the Arg72Pro polymorphism on retinal neurodegeneration and functional recovery in patients. The underlying mechanisms were analyzed in a humanized TP53 Arg72Pro RD mouse model. In a cohort of 180 patients, carriers of the Pro allele exhibited decreased apoptotic gene expression and improved visual recovery. Complementary findings in mice revealed that the Pro variant preserved photoreceptor integrity and reduced apoptosis rates following RD. Our findings highlight the potential of this TP53 polymorphism as a biomarker for RD outcomes and a tool for tailoring therapies. This study underscores the importance of integrating genetic profiling into personalized medicine approaches to improve recovery of RD patients’ visual outcomes.

To uncover the negative impacts of heavy metals on carbohydrate metabolism, their mechanisms and contributory factors, as well as their role on the etiopathogenesis, pathophysiology, and progression of eye diseases. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), various databases were searched (e.g., Scopus, PubMed, etc.) to collect evidence on the link and role of heavy metals in carbohydrate metabolism and pathogenesis of eye diseases. Included studies were appraised for quality using the Critical Appraisal Skills Programme checklists and extracted data were analyzed using the narrative synthesis method. Of the 128 papers retrieved, 24 papers met the inclusion criteria. Heavy metals are associated with the onset and progression of diabetes and eye diseases secondary to diabetes (age-related macular degeneration, cataract, and diabetic retinopathy) majorly via toxic interference (induction, inhibition and/or deactivation) of glucose metabolizing enzymes and oxidative stress. The etiology of DR is intricate and includes the simultaneous disruption of several metabolic and signaling mechanisms within the retinal neurovascular unit. The retina is more susceptible to metal-induced toxicities due to the high affinity of heavy metals to melanin content of the retinal epithelium. This study emphasizes the harmful effects of chronic and intermittent exposure to heavy metals, suggesting no safe exposure levels. To prevent eye diseases secondary to heavy metals-induced altered carbohydrate metabolism, metal chelators, low glycemic diets, and lifestyle modifications should be exploited among vulnerable populations.

Description of longitudinal follow-up of 13 patients diagnosed with Idiopathic Multifocal Pigment Epithelial Detachments (IMPED), a rare condition first described by Gass et al., in 2005. This retrospective case series included 13 patients in the first to sixth decades of life who presented with multiple bilateral PEDs, confirmed by Optical Coherence Tomography. Ancillary imaging included fundus autofluorescence and angiography to exclude alternative diagnoses such as Central Serous Chorioretinopathy and Polypoidal Choroidovasculopathy. Electrophysiology testing, including full-field electroretinography (FFERG) and electrooculography (EOG), assessed both retinal and pigment epithelium function. Visual acuity (VA) was documented over a mean follow-up of 6.5 years (range: 0.1-26.4 years). All patients demonstrated stable VA during follow-up. Electrophysiology was normal in tested patients (FFERG: 9/13, EOG: 7/13). Genetic testing (10/13) was non-diagnostic. Two patients (including a patient previously receiving anti-VEGF without exudation) exhibited outer retinal atrophy. One patient developed a choroidal neovascularization (CNV) during follow-up, which resolved with intravitreal aflibercept. IMPED should remain a diagnosis of exclusion, confirmed after sufficient follow-up demonstrating no progression. While our study implies a generally favorable prognosis, continuous monitoring is necessary to assess long-term risks, including potential complications such as the development of CNV and/or atrophy.

Retinitis pigmentosa (RP) is a leading cause of blindness and genetically induces impairment of the retinal epithelium and photoreceptors. In this study, we investigated the decline in the visual response and visual ability during disease progression. This understanding is crucial for disease staging in patients, establishing therapeutic plans in advance, and evaluating the effects of interventional treatments. We used a rat model of inherited RP (Royal College of Surgeons [RCS] rats) and evaluated form visual acuity and light perception using behavioral tests and electrophysiological recordings in the dorsal lateral geniculate nucleus, superior colliculus, and primary visual cortex. The perceptual form vision (detection of grating stimulus) was attenuated by 9 weeks old. The neural responses in the three early visual areas to flashing grating stimuli with various contrasts and spatial frequencies showed similar degeneration progress as the behavioral evaluations. Light perception (detection of a bright uniform light source) was maintained until at least 11 weeks old. The neural responses to the uniform flashlight stimulus in the three early visual areas were maintained during the same period. Our findings suggest that form vision is primarily affected by the progression of RP, whereas non-form vision is potentially robust to retinal degeneration. This maintenance of light perception is likely due to the preserved function of intrinsically photosensitive retinal ganglion cells. These results provide useful and fundamental knowledge for evaluating the protective or restorative effects of experimental treatments for RP.

ABSTRACTAge‐related macular degeneration (AMD) is a common degenerative disease of the eye that ultimately leads to irreversible vision loss. Asparagine synthase (ASNS) is an aminotransferase, and its low expression is associated with retinal damage. The present study centered on the protective effect of ASNS on retinal epithelial cells. We found that in the AMD cell model, overexpression of ASNS reduced SA‐β‐gal staining and ROS production, and increased cell viability in H2O2‐treated ARPE‐19 cells. In addition, overexpression of ASNS increased glucose consumption, lactate production, extracellular acidification rate (ECAR), and oxygen consumption rate (OCR) and enhanced the expression of glycolytic markers. Molecular mechanistic studies revealed that ASNS was highly bound to USP13 protein and increased USP13 expression. Furthermore, ASNS protected the retinal epithelium from oxidative stress damage in an animal model of AMD. Taken together, these findings suggest that the ASNS/USP13 axis plays an important regulatory role in AMD development. Our findings not only emphasized the understanding of the role of glucose metabolism in AMD, but also identified a promising target for future AMD therapy.

Amyloidogenic transthyretin (ATTR) amyloidosis is a systemic disease characterized by the deposition of amyloid fibrils made of transthyretin. Transthyretin is primarily produced in tetrameric form by the liver, but also by retinal epithelium and choroid plexus. The deposition of these fibrils in the myocardium and peripheral nerves causes cardiomyopathies and neuropathies, respectively. Using cryoelectron microscopy (cryo-EM), we investigated fibrils extracted from cardiac and nerve tissues of an ATTRv-V30M patient. We found consistent fibril structures from both tissues, similar to cardiac fibrils previously described, but different from vitreous humor fibrils of the same genotype. Our findings, along with previous ATTR fibrils structural studies, suggest a uniform fibrillar architecture across different tissues when transthyretin originates from the liver. This study advances our understanding of how deposition and production sites influence fibril structure in ATTRv-V30M amyloidosis.

Coming in a variety of forms, melanin is one of the most abundant, stable, diverse, and evolutionarily ancient pigments found in living things in nature. These pigments often serve protective functions, typically well-adapted to their specific roles. One such protective function is metal chelation and cation exchange, which help regulate and buffer metal concentrations within cells. By binding to certain metals, melanin can acquire magnetic properties. Because of this, it may play a role in magnetic effects and possibly in the response of organisms to external magnetic fields and magnetic sensing. While there is melanin in plants, microbes, fungi, and invertebrates, certain types of melanin are specifically associated with the retina in vertebrates, including migrating bird and fish species. In this review, we examine studies focusing on the properties of melanin in these parts of the body and their possible association with magnetic sensing, and generally, magnetic sensing in the retina.

Perturbed cell cycle phase-dependent positioning and nuclear migration of retinal progenitors along the apico-basal axis underlie global retinal disorganization in the LCA8-like mouse model

Oligoarginine cell-penetrating peptides (CPPs) are short peptides that can enhance drug delivery into cells and are of particular interest in ocular topical formulations for age-related macular degeneration (AMD) treatments. The length and structural characteristics of these peptides are considered crucial for drug delivery. This study investigates how oligoarginine length (Rn) affects their penetration mechanism, drug delivery capabilities, and antimicrobial properties, providing insights into their potential roles in AMD treatment delivery. In this study, oligoarginine peptides showed limited pore-forming abilities in a carboxyfluorescein-containing liposomal model, with R9 being the only oligoarginine length recording a significant pore-formation level. Their antibacterial efficacy depended on both the CPP length and bacterial class, with longer peptides exhibiting stronger antibacterial effects. Importantly, oligoarginine was found nontoxic to relevant mammalian cells for ocular delivery. The membrane translocation abilities of oligoarginine were consistent regardless of cargo presence. Additionally, cargo delivery by oligoarginine across in vitro cellular models for ocular delivery was dependent on peptide length and cell type, with longer chains being more effective at cargo uptake in a corneal epithelium cell line, and with shorter chains proving more effective for cargo delivery in a retinal epithelium cell line. This proposes that the chain length of oligoarginine could be used as a strategic tool in the formulation process to selectively target distinct regions of the eye. Overall, this study expands our understanding of how oligoarginine CPPs can be applied as penetration enhancers to improve the delivery of therapeutics in an ocular topical formulation within the clinical context of AMD.

The gyrate atrophy of the choroid and retina (GACR) is a rare genetic disease for which no definitive cure is available. GACR is due to the deficit of ornithine aminotransferase (hOAT), a pyridoxal 5'-phosphate-dependent enzyme responsible for ornithine catabolism. The hallmark of the disease is plasmatic ornithine accumulation, which damages retinal epithelium leading to progressive vision loss and blindness within the fifth decade. Here, we characterized the biochemical properties of tetrameric and dimeric hOAT and evaluated hOAT loaded in red blood cells (RBCs) as a possible enzyme replacement therapy (ERT) for GACR. Our results show that (i) hOAT has a relatively wide specificity for amino acceptors, with pyruvate being the most suitable candidate for ornithine catabolism within RBCs; (ii) both the tetrameric and dimeric enzyme can be loaded in RBC retaining their activity; and (iii) hOAT displays reduced stability in plasma, but is partly protected from inactivation upon incubation in a mixture mimicking the intracellular erythrocyte environment. Preliminary ex vivo experiments indicate that hOAT-loaded RBCs are able to metabolize extracellular ornithine at a concentration mimicking that found in patients, both in buffer and, although with lower efficiency, in plasma. Overall, our data provide a proof of concept that an RBC-mediated ERT is feasible and can be exploited as a new therapeutic approach in GACR.

The primary cilium is a characteristic feature of most non-immune cells and functions as an environmental signal transduction sensor. The defects in primary cilium have profound effects on the developmental program, including the maturation of retinal epithelium. The ciliary length is tightly regulated during ciliogenesis, but the impact of inflammation on ciliary length remains elusive. The current study investigates the outcome of inflammatory stimuli for the primary cilium length in retinal epithelium cells and mouse embryonic fibroblasts. Here, we report that exposure to the pro-inflammatory cytokine TNF-alpha elongates cilia in a mixed-lineage kinase (MLK)-dependent manner. Pro-inflammatory stimuli such as bacterial LPS and interferon-gamma have similar effects on ciliary length. In contrast, febrile condition-mimicking heat stress dramatically reduced the number of ciliated cells regardless of TNF-alpha exposure but did not shorten TNF-induced elongation, suggesting distinct but rapid effects of inflammatory stresses on ciliogenesis.

ATTR amyloidosis is a systemic disease characterized by the deposition of amyloid fibrils made of transthyretin, a protein integral to transporting retinol and thyroid hormones. Transthyretin is primarily produced by the liver and circulates in blood as a tetramer. The retinal epithelium also secretes transthyretin, which is secreted to the vitreous humor of the eye. Because of mutations or aging, transthyretin can dissociate into amyloidogenic monomers triggering amyloid fibril formation. The deposition of transthyretin amyloid fibrils in the myocardium and peripheral nerves causes cardiomyopathies and neuropathies, respectively. Using cryo-electron microscopy, here we determined the structures of amyloid fibrils extracted from cardiac and nerve tissues of an ATTRv-V30M patient. We found that fibrils from both tissues share a consistent structural conformation, similar to the previously described structure of cardiac fibrils from an individual with the same genotype, but different from the fibril structure obtained from the vitreous humor. Our study hints to a uniform fibrillar architecture across different tissues within the same individual, only when the source of transthyretin is the liver. Moreover, this study provides the first description of ATTR fibrils from the nerves of a patient and enhances our understanding of the role of deposition site and protein production site in shaping the fibril structure in ATTRv-V30M amyloidosis.

Abstract Purpose: To highlight the high positive predictive value of the retinal pigmentary epithelium (RPE) irregularity and the shallow irregular retinal pigmented epithelium elevation (SIRE) sign in identifying nonexudative neovascular membranes and underscore the usefulness of these signs in clinical practice. Methods: Retrospective case series analysis conducted in the medical retina clinic in one center. Results: Seven cases of patients with nonexudative neovascular membranes confirmed with optical coherence tomography angiography (OCTA) imaging where RPE irregularity and/or SIRE sign had been described on standard structural optical coherence tomography (OCT). Conclusion: In this case series, we present a variety of phenotypes, some with apparently benign alterations, in which NE-MNV has been identified. Our findings suggest that OCTA screening for neovascular membranes is a useful tool for any patient presenting with irregular RPE and SIRE signal in their structural OCT image.

Tissue fusion is a critical process that is repeated in multiple contexts during embryonic development and shares common attributes to processes such as wound healing and metastasis. Ocular coloboma is a developmental eye disorder that presents as a physical gap in the ventral eye, and is a major cause of childhood blindness. Coloboma results from fusion failure between opposing ventral retinal epithelia, but there are major knowledge gaps in our understanding of this process at the molecular and cell behavioural levels. Here we catalogue the expression of cell adhesion proteins: N-cadherin, E-cadherin, R-cadherin, ZO-1, and the EMT transcriptional activator and cadherin regulator SNAI2, in the developing chicken embryonic eye. We find that fusion pioneer cells at the edges of the fusing optic fissure have unique and dynamic expression profiles for N-cad, E-cad and ZO-1, and that these are temporally preceded by expression of SNAI2. This highlights the unique properties of these cells and indicates that regulation of cell adhesion factors may be a critical process in optic fissure closure.