Mitochondrial quality control in non-exudative age-related macular degeneration: From molecular mechanisms to structural and functional recovery

Non-exudative age-related macular degeneration (NE-AMD) is the leading blindness cause in the elderly. Clinical and experimental evidence supports that early alterations in macular retinal pigment epithelium (RPE) mitochondria play a key role in NE-AMD-induced damage. Mitochondrial dynamics (biogenesis, fusion, fission, and mitophagy), which is under the central control of AMP-activated kinase (AMPK), in turn, determines mitochondrial quality. We have developed a NE-AMD model in C57BL/6J mice induced by unilateral superior cervical ganglionectomy (SCGx), which progressively reproduces the disease hallmarks circumscribed to the temporal region of the RPE/outer retina that exhibits several characteristics of the human macula. In this work we have studied RPE mitochondrial structure, dynamics, function, and AMPK role on these parameters' regulation at the nasal and temporal RPE from control eyes and at an early stage of experimental NE-AMD (i.e., 4 weeks post-SCGx). Although RPE mitochondrial mass was preserved, their function, which was higher at the temporal than at the nasal RPE in control eyes, was significantly decreased at 4 weeks post-SCGx at the same region. Mitochondria were bigger, more elongated, and with denser cristae at the temporal RPE from control eyes. Exclusively at the temporal RPE, SCGx severely affected mitochondrial morphology and dynamics, together with the levels of phosphorylated AMPK (p-AMPK). AMPK activation with metformin restored RPE p-AMPK levels, and mitochondrial dynamics, structure, and function at 4 weeks post-SCGx, as well as visual function and RPE/outer retina structure at 10 weeks post-SCGx. These results demonstrate a key role of the temporal RPE mitochondrial homeostasis as an early target for NE-AMD-induced damage, and that pharmacological AMPK activation could preserve mitochondrial morphology, dynamics, and function, and, consequently, avoid the functional and structural damage induced by NE-AMD.

Novel CCR3-targeted cyclic peptides as potential therapeutic agents for age-related macular degeneration via inhibiting angiogenesis and reducing retinal photoreceptor damage

The prolonged intravitreal administration of anti-vascular endothelial growth factor (VEGF) drugs is prone to inducing aberrant retinal vascular development and causing damage to retinal neurons. Hence, we have taken an alternative approach by designing and synthesizing a series of cyclic peptides targeting CC motif chemokine receptor 3 (CCR3). Based on the binding mode of the N-terminal region in CCR3 protein to CCL11, we used computer-aided identification of key amino acid sequence, conformational restriction through different cyclization methods, designed and synthesized a series of target cyclic peptides, and screened the preferred compound IB-2 through affinity. IB-2 exhibits excellent anti-angiogenic activity in HRECs. The apoptosis level of 661W cells demonstrated a significant decrease with the escalating concentration of IB-2. This suggests that IB-2 may have a protective effect on photoreceptor cells. In vivo experiments have shown that IB-2 significantly reduces retinal vascular leakage and choroidal neovascularization (CNV) area in a laser-induced mouse model of CNV. These findings indicate the potential of IB-2 as a safe and effective therapeutic agent for AMD, warranting further development.

Mast cells in human choroid and their role in age-related macular degeneration (AMD)

The role of mast cells in physiologic and pathological processes extends far beyond the allergy processes: they are involved in wound healing, chronic inflammation, and tumor growth. This short article emphasizes the role played by mast cells in age-related macular degeneration (AMD). Mast cells can induce angiogenesis and are present around Bruch's membrane during the early and late stages of choroidal neovascularization in AMD. Proteolytic enzymes released by mast cells lead to thinning of the choroid in AMD as well as degradation of vascular basement membranes and Bruch's membrane, which in turn could result in retinal pigment epithelial death and choriocapillaris degeneration in geographical atrophy and exudative AMD.

Crosstalk Between Microglia and Müller Glia in the Age-Related Macular Degeneration: Role and Therapeutic Value of Neuroinflammation

Age-related macular degeneration (AMD) is a progressive neurodegeneration disease that causes photoreceptor demise and vision impairments. In AMD pathogenesis, the primary death of retinal neurons always leads to the activation of resident microglia. The migration of activated microglia to the ongoing retinal lesion and their morphological transformation from branching to ameboid-like are recognized as hallmarks of AMD pathogenesis. Activated microglia send signals to Müller cells and promote them to react correspondingly to damaging stimulus. Müller cells are a type of neuroglia cells that maintain the normal function of retinal neurons, modulating innate inflammatory responses, and stabilize retinal structure. Activated Müller cells can accelerate the progression of AMD by damaging neurons and blood vessels. Therefore, the crosstalk between microglia and Müller cells plays a homeostatic role in maintaining the retinal environment, and this interaction is complicatedly modulated. In particular, the mechanism of mutual regulation between the two glia populations is complex under pathological conditions. This paper reviews recent findings on the crosstalk between microglia and Müller glia during AMD pathology process, with special emphasis on its therapeutic potentials.

An adeno-associated virus variant enabling efficient ocular-directed gene delivery across species

Recombinant adeno-associated viruses (rAAVs) have emerged as promising gene therapy vectors due to their proven efficacy and safety in clinical applications. In non-human primates (NHPs), rAAVs are administered via suprachoroidal injection at a higher dose. However, high doses of rAAVs tend to increase additional safety risks. Here, we present a novel AAV capsid (AAVv128), which exhibits significantly enhanced transduction efficiency for photoreceptors and retinal pigment epithelial (RPE) cells, along with a broader distribution across the layers of retinal tissues in different animal models (mice, rabbits, and NHPs) following intraocular injection. Notably, the suprachoroidal delivery of AAVv128-anti-VEGF vector completely suppresses the Grade IV lesions in a laser-induced choroidal neovascularization (CNV) NHP model for neovascular age-related macular degeneration (nAMD). Furthermore, cryo-EM analysis at 2.1 Å resolution reveals that the critical residues of AAVv128 exhibit a more robust advantage in AAV binding, the nuclear uptake and endosome escaping. Collectively, our findings highlight the potential of AAVv128 as a next generation ocular gene therapy vector, particularly using the suprachoroidal delivery route.

Graft cell expansion from hiPSC-RPE strip after transplantation in primate eyes with or without RPE damage

Clinical studies using suspensions or sheets of human pluripotent cell-derived retinal pigment epithelial cells (hiPSC-RPE) have been conducted globally for diseases such as age-related macular degeneration. Despite being minimally invasive, cell suspension transplantation faces challenges in targeted cell delivery and frequent cell leakage. Conversely, although the RPE sheet ensures targeted delivery with correct cell polarity, it requires invasive surgery, and graft preparation is time-consuming. We previously reported hiPSC-RPE strips as a form of quick cell aggregate that allows for reliable cell delivery to the target area with minimal invasiveness. In this study, we used a microsecond pulse laser to create a local RPE ablation model in cynomolgus monkey eyes. The hiPSC-RPE strips were transplanted into the RPE-ablated and intact sites. The hiPSC-RPE strip stably survived in all transplanted monkey eyes. The expansion area of the RPE from the engrafted strip was larger at the RPE injury site than at the intact site with no tumorigenic growth. Histological observation showed a monolayer expansion of the transplanted RPE cells with the expression of MERTK apically and collagen type 4 basally. The hiPSC-RPE strip is considered a beneficial transplantation option for RPE cell therapy.

Rescue of cone and rod photoreceptor function in a CDHR1-model of age-related retinal degeneration

Age-related macular degeneration (AMD) is the most common cause of untreatable blindness in the developed world. Recently, CDHR1 has been identified as the cause of a subset of AMD that has the appearance of the "dry" form, or geographic atrophy. Biallelic variants in CDHR1-a specialized protocadherin highly expressed in cone and rod photoreceptors-result in blindness from shortened photoreceptor outer segments and progressive photoreceptor cell death. Here we demonstrate long-term morphological, ultrastructural, functional, and behavioral rescue following CDHR1 gene therapy in a relevant murine model, sustained to 23-months after injection. This represents the first demonstration of rescue of a monogenic cadherinopathy in vivo. Moreover, the durability of CDHR1 gene therapy seems to be near complete-with morphological findings of the rescued retina not obviously different from wildtype throughout the lifespan of the mouse model. A follow-on clinical trial in patients with CDHR1-associated retinal degeneration is warranted. Hypomorphic CDHR1 variants may mimic advanced dry AMD. Accurate clinical classification is now critical, as their pathogenesis and treatment are distinct.

Screening and evaluation of antioxidants for retinal pigment epithelial cell protection: L-ergothioneine as a novel therapeutic candidate through NRF2 activation

The continual exposure of retinal tissues to oxidative stress leads to discernible anatomical and physiological alterations. Specifically, the onslaught of oxidative damage escalates the irreversible death of retinal pigmented epithelium (RPE) cells, pinpointed as the fundamental pathological event in dry age-related macular degeneration (AMD). There is a conspicuous lack of effective therapeutic strategies to counteract this degenerative process. This study screened a library of antioxidants for their ability to protect RPE cells against oxidative stress and identified L-ergothioneine (EGT) as a potent cytoprotective agent. L-ergothioneine provided efficient protection against oxidative stress-damaged RPE and maintained cell redox homeostasis and normal physiological functions. It maintained the normal structure of the retina in mice under oxidative stress conditions. Transcriptomic analysis revealed that EGT counteracted major gene expression changes induced by oxidative stress. It upregulated antioxidant gene expression and inhibited NRF2 translocation. The inhibition of NRF2 abolished EGT's protective effects, suggesting that NRF2 activation contributes to its mechanism of action. In conclusion, we identified EGT as a safe and effective small-molecule compound that is expected to be a novel antioxidative agent for treating AMD.

Establishing chronic models of age-related macular degeneration via long-term iron ion overload

Age-related macular degeneration (AMD) is characterized by the degenerative senescence in the retinal pigment epithelium (RPE) and photoreceptors, which is accompanied by the accumulation of iron ions in the aging retina. However, current models of acute oxidative stress are still insufficient to simulate the gradual progression of AMD. To address this, we established chronic injury models by exposing the aRPE-19 cells, 661W cells, and mouse retina to iron ion overload over time. Investigations at the levels of cell biology and molecular biology were performed. It was demonstrated that long-term treatment of excessive iron ions induced senescence-like morphological changes, decreased cell proliferation, and impaired mitochondrial function, contributing to apoptosis. Activation of the mitogen-activated protein kinase (MAPK) pathway and the downstream molecules were confirmed both in the aRPE-19 and 661W cells. Furthermore, iron ion overload resulted in dry AMD-like lesions and decreased visual function in the mouse retina. These findings suggest that chronic exposure to overloading iron ions plays a significant role in the pathogenesis of retinopathy and provide a potential model for future studies on AMD.NEW & NOTEWORTHY To explore the possibility of constructing reliable research carriers on age-related macular degeneration (AMD), iron ion overload was applied to establish models in vitro and in vivo. Subsequent investigations into cellular physiology and molecular biology confirmed the presence of senescence in these models. Through this study, we hope to provide a better option of feasible methods for future researches into AMD.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN GIANT CELL ARTERITIS

PURPOSE

To describe a representative case and review the literature on paracentral acute middle maculopathy (PAMM) and giant cell arteritis (GCA).

METHODS

A review of the English-language ophthalmic literature was performed using the search terms of PAMM, giant cell arteritis, and temporal arteritis.

RESULTS

A 72-year-old woman with PAMM as the presenting ophthalmic manifestation of GCA was described with a review of the prior cases from the literature. It was found that there were 26 cases of PAMM in GCA. In 19 of 26 cases, PAMM was associated with no other fundus abnormalities and was only seen on multimodal imaging including optical coherence tomography.

CONCLUSION

PAMM can cause acute paracentral visual loss, and GCA should be suspected in all cases of PAMM of the elderly patients, even when isolated and not associated with constitutional symptoms of GCA.

Complement regulation in the eye: implications for age-related macular degeneration

Careful regulation of the complement system is critical for enabling complement proteins to titrate immune defense while also preventing collateral tissue damage from poorly controlled inflammation. In the eye, this balance between complement activity and inhibition is crucial, as a low level of basal complement activity is necessary to support ocular immune privilege, a prerequisite for maintaining vision. Dysregulated complement activation contributes to parainflammation, a low level of inflammation triggered by cellular damage that functions to reestablish homeostasis, or outright inflammation that disrupts the visual axis. Complement dysregulation has been implicated in many ocular diseases, including glaucoma, diabetic retinopathy, and age-related macular degeneration (AMD). In the last two decades, complement activity has been the focus of intense investigation in AMD pathogenesis, leading to the development of novel therapeutics for the treatment of atrophic AMD. This Review outlines recent advances and challenges, highlighting therapeutic approaches that have advanced to clinical trials, as well as providing a general overview of the complement system in the posterior segment of the eye and selected ocular diseases.

Fructosyl Amino Oxidase as a Therapeutic Enzyme in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is an age-related disorder that is a global public health problem. The non-enzymatic Maillard reaction results in the formation of advanced glycation end products (AGEs). Accumulation of AGEs in drusen plays a key role in AMD. AGE-reducing drugs may contribute to the prevention and treatment of AGE-related disease. Fructosamine oxidase (FAOD) acts on fructosyl lysine and fructosyl valine. Based upon the published results of fructosamine 3-kinase (FN3K) and FAOD obtained in cataract and presbyopia, we studied ex vivo FAOD treatment as a non-invasive AMD therapy. On glycolaldehyde-treated porcine retinas, FAOD significantly reduced AGE autofluorescence (p = 0.001). FAOD treatment results in a breakdown of AGEs, as evidenced using UV fluorescence, near-infrared microspectroscopy on stained tissue sections of human retina, and gel permeation chromatography. Drusen are accumulations of AGEs that build up between Bruch's membrane and the retinal pigment epithelium. On microscopy slides of human retina affected by AMD, a significant reduction in drusen surface to 45 ± 21% was observed following FAOD treatment. Enzymatic digestion followed by mass spectrometry of fructose- and glucose-based AGEs (produced in vitro) revealed a broader spectrum of substrates for FAOD, as compared to FN3K, including the following: fructosyllysine, carboxymethyllysine, carboxyethyllysine, and imidazolone. In contrast to FN3K digestion, agmatine (4-aminobutyl-guanidine) was formed following FAOD treatment in vitro. The present study highlights the therapeutic potential of FAOD in AMD by repairing glycation-induced damage.

Retinal and choroidal efficacy of switching treatment to faricimab in recalcitrant neovascular age related macular degeneration

Aim of this study was to evaluate the efficacy of switching treatment to faricimab in neovascular age-related macular degeneration (nAMD) from other anti-VEGF agents. Fifty-eight eyes of fifty-one patients with nAMD and a full upload series of four faricimab injections were included. Demographic data, multimodal imaging and treatment parameters were recorded. The primary outcome measures were changes in central subfield thickness (CST) and subfoveal choroidal thickness (SFCT). A subgroup analysis was performed for eyes with prior ranibizumab (R) or aflibercept (A) treatment. Mean injection intervals before and after switching were comparable (33.8 ± 11.2 vs. 29.3 ± 2.6 days; p = 0.08). Mean CST of 361.4 ± 108.1 µm prior to switching decreased significantly to 318.3 ± 97.7 µm (p < 0.01) after the third faricimab injection, regardless of prior anti-VEGF treatment (p < 0.01). Although SFCT slightly improved for the whole cohort from 165.8 ± 76.8 µm to 161.0 ± 82,8 µm (p = 0.029), subgroup analysis did not confirm this positive effect (subgroup R: p = 0.604; subgroup A: p = 0.306). In patients with a suboptimal response to aflibercept or ranibizumab in nAMD, farcimab can improve CST and slightly improve or maintain SFCT. Further prospective randomized trials are warranted.

An overview of retinal light damage models for preclinical studies on age-related macular degeneration: identifying molecular hallmarks and therapeutic targets

Age-related macular degeneration (AMD) is a complex, multifactorial disease leading to progressive and irreversible retinal degeneration, whose pathogenesis has not been fully elucidated yet. Due to the complexity and to the multiple features of the disease, many efforts have been made to develop animal models which faithfully reproduce the overall AMD hallmarks or that are able to mimic the different AMD stages. In this context, light damage (LD) rodent models of AMD represent a suitable and reliable approach to mimic the different AMD forms (dry, wet and geographic atrophy) while maintaining the time-dependent progression of the disease. In this review, we comprehensively reported how the LD paradigms reproduce the main features of human AMD. We discuss the capability of these models to broaden the knowledge in AMD research, with a focus on the mechanisms and the molecular hallmarks underlying the pathogenesis of the disease. We also critically revise the remaining challenges and future directions for the use of LD models.

Microglial repopulation restricts ocular inflammation and choroidal neovascularization in mice

Introduction

Age-related macular degeneration (AMD) is a prevalent, chronic and progressive retinal degenerative disease characterized by an inflammatory response mediated by activated microglia accumulating in the retina. In this study, we demonstrate the therapeutically effects and the underlying mechanisms of microglial repopulation in the laser-induced choroidal neovascularization (CNV) model of exudative AMD.

Methods

The CSF1R inhibitor PLX3397 was used to establish a treatment paradigm for microglial repopulation in the retina. Neovascular leakage and neovascular area were examined by fundus fluorescein angiography (FFA) and immunostaining of whole-mount RPE-choroid-sclera complexes in CNV mice receiving PLX3397. Altered cellular senescence was measured by beta-galactosidase (SA-β-gal) activity and p16INK4a expression. The effect and mechanisms of repopulated microglia on leukocyte infiltration and the inflammatory response in CNV lesions were analyzed.

Results

We showed that ten days of the CSF1R inhibitor PLX3397 treatment followed by 11 days of drug withdrawal was sufficient to stimulate rapid repopulation of the retina with new microglia. Microglial repopulation attenuated pathological choroid neovascularization and dampened cellular senescence in CNV lesions. Repopulating microglia exhibited lower levels of activation markers, enhanced phagocytic function and produced fewer cytokines involved in the immune response, thereby ameliorating leukocyte infiltration and attenuating the inflammatory response in CNV lesions.

Discussion

The microglial repopulation described herein are therefore a promising strategy for restricting inflammation and choroidal neovascularization, which are important players in the pathophysiology of AMD.

Giant retinal pigment epithelium tears with membranous nephropathy: a case report and literature review

BACKGROUND

Kidney and eye diseases may be closely linked. Tears of the retinal pigment epithelium (RPE) have been reported to be related to kidney diseases, such as IgA nephropathy and light-chain deposition disease. However, pigment epithelium tears associated with membranous nephropathy have not been reported or systematically analysed.

CASE PRESENTATION

A 68-year-old man presented with decreased right eye visual acuity. Optical coherence tomography (OCT) revealed cystic macular edema, localized serous detachment of the retina and loss of the outer retinal structure in the right eye and retinal pigment epithelium detachment (PED) combined with serous detachment of the retina in the left eye. Fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) revealed giant RPE tears in the right eye and exudative age-related macular degeneration in the left eye. The patient also suffered from severe membranous nephropathy-autoimmune glomerulonephritis. Renal biopsy immunofluorescence revealed a roughly granular pattern, with immunoglobulin G (IgA), immunoglobulin G (IgG), IgM, complement C3(Components 3), λ light chain and κ light chain subepithelial staining.

CONCLUSIONS

It is hypothesized that severe membranous nephropathy caused immune complex deposition on the surface of Bruch membrane, resulting in weakened adhesion between the RPE and Bruch membrane and impaired RPE pump function, combined with age-related macular degeneration, leading to giant RPE tears in the right eye. Close attention should be given to the ocular condition of patients with membranous nephropathy to facilitate timely treatment and avoid serious consequences.

FNeXter: A Multi-Scale Feature Fusion Network Based on ConvNeXt and Transformer for Retinal OCT Fluid Segmentation

The accurate segmentation and quantification of retinal fluid in Optical Coherence Tomography (OCT) images are crucial for the diagnosis and treatment of ophthalmic diseases such as age-related macular degeneration. However, the accurate segmentation of retinal fluid is challenging due to significant variations in the size, position, and shape of fluid, as well as their complex, curved boundaries. To address these challenges, we propose a novel multi-scale feature fusion attention network (FNeXter), based on ConvNeXt and Transformer, for OCT fluid segmentation. In FNeXter, we introduce a novel global multi-scale hybrid encoder module that integrates ConvNeXt, Transformer, and region-aware spatial attention. This module can capture long-range dependencies and non-local similarities while also focusing on local features. Moreover, this module possesses the spatial region-aware capabilities, enabling it to adaptively focus on the lesions regions. Additionally, we propose a novel self-adaptive multi-scale feature fusion attention module to enhance the skip connections between the encoder and the decoder. The inclusion of this module elevates the model's capacity to learn global features and multi-scale contextual information effectively. Finally, we conduct comprehensive experiments to evaluate the performance of the proposed FNeXter. Experimental results demonstrate that our proposed approach outperforms other state-of-the-art methods in the task of fluid segmentation.

The Role of Glutathione in Age-Related Macular Degeneration (AMD)

Age-related macular degeneration (AMD) is a chronic disease that usually develops in older people. Pathogenetic changes in this disease include anatomical and functional complexes. Harmful factors damage the retina and macula. These changes may lead to partial or total loss of vision. The disease can occur in two clinical forms: dry (the progression is slow and gentle) and exudative (wet-progression is acute and severe), which usually starts in the dry form; however, the coexistence of both forms is possible. The etiology of AMD is not fully understood, and the precise mechanisms of the development of this illness are still unknown. Extensive genetic studies have shown that AMD is a multi-factorial disease and that genetic determinants, along with external and internal environmental and metabolic-functional factors, are important risk factors. This article reviews the role of glutathione (GSH) enzymes engaged in maintaining the reduced form and polymorphism in glutathione S-transferase theta-1 (GSTT1) and glutathione S-transferase mu-1 (GSTM1) in the development of AMD. We only chose papers that confirmed the influence of the parameters on the development of AMD. Because GSH is the most important antioxidant in the eye, it is important to know the influence of the enzymes and genetic background to ensure an optimal level of glutathione concentration. Numerous studies have been conducted on how the glutathione system works till today. This paper presents the current state of knowledge about the changes in GSH, GST, GR, and GPx in AMD. GST studies clearly show increased activity in ill people, but for GPx, the results relating to activity are not so clear. Depending on the research, the results also suggest higher and lower GPx activity in patients with AMD. The analysis of polymorphisms in GST genes confirmed that mutations lead to weaker antioxidant barriers and may contribute to the development of AMD; unfortunately, a meta-analysis and some research did not confirm that connection. Unspecific results of many of the parameters that make up the glutathione system show many unknowns. It is so important to conduct further research to understand the exact mechanism of defense functions of glutathione against oxidative stress in the human eye.

Assessing fall risk and equilibrium function in patients with age-related macular degeneration and glaucoma: An observational study

BACKGROUND

Falls in older adults are a significant public health concern, and age-related macular degeneration (AMD) and glaucoma have been identified as potential visual risk factors. This study was designed to assess equilibrium function, fall risk, and fall-related self-efficacy (an individual's belief in their capacity to act in ways necessary to reach specific goals) in patients with AMD and glaucoma.

METHODS

This observational study was performed at the Otorhinolaryngology Department of Shinseikai Toyama Hospital. The cohort comprised 60 participants (AMD; n = 30; median age, 76.0 years; and glaucoma; n = 30; median age, 64.5 years). Visual acuity and visual fields were assessed using the decimal best-corrected visual acuity and Humphrey visual field tests, respectively. The evaluation metrics included pathological eye movement analysis, bedside head impulse test, single-leg upright test, eye-tracking test, optokinetic nystagmus, and posturography. Furthermore, we administered questionnaires for fall risk determinants including the Dizziness Handicap Inventory, Activities-Specific Balance Confidence Scale, Falls Efficacy Scale-International, and Hospital Anxiety and Depression Scale. The collected data were analyzed using descriptive statistics, and Spearman's correlation analysis was employed to examine the interrelations among the equilibrium function, fall risk, and other pertinent variables.

RESULTS

Most participants exhibited standard outcomes in equilibrium function evaluations. Visual acuity and field deficits had a minimal impact on subjective dizziness manifestations, degree of disability, and fall-related self-efficacy. Both groups predominantly showed high self-efficacy. No significant correlation was observed between visual acuity or field deficits and body equilibrium function or fall risk. However, greater peripheral visual field impairment was associated with a tendency for sensory reweighting from visual to somatosensory.

CONCLUSION

Self-efficacy was higher and fall risk was relatively lower among patients with mild-to-moderate visual impairment, with a tendency for sensory reweighting from visual to somatosensory in those with greater peripheral visual field impairment. Further studies are required to validate these findings.

Estrogen related receptor alpha: Potential modulator of age-related macular degeneration

To develop effective therapies for complex blinding diseases such as age-related macular degeneration (AMD), identification of mechanisms involved in its initiation and progression is needed. The estrogen-related receptor alpha (ESRRA) is an orphan nuclear receptor that regulates several AMD-associated pathogenic pathways. However, it has not been investigated in detail in the ocular posterior pole during aging or in AMD. This review delves into the literature highlighting the significance of ESRRA as a molecular target that may be important in the pathobiology of AMD, and discusses data available supporting the targeting of this receptor signaling pathway as a therapeutic option for AMD.

Polarization-Sensitive OCT Imaging of Scleral Abnormalities in Eyes With High Myopia and Dome-Shaped Macula

Importance

The relevance of visualizing scleral fiber orientation may offer insights into the pathogenesis of pathologic myopia, including dome-shaped maculopathy (DSM).

Objective

To investigate the orientation and density of scleral collagen fibers in highly myopic eyes with and without DSM by polarization-sensitive optical coherence tomography (PS-OCT).

Design, Setting, and Participants

This case series included patients with highly myopic eyes (defined as a refractive error ≥6 diopters or an axial length ≥26.5 mm) with and without a DSM examined at a single site in May and June 2019. Analysis was performed from September 2019 to October 2023.

Exposures

The PS-OCT was used to study the birefringence and optic axis of the scleral collagen fibers.

Main Outcomes and Measures

The orientation and optic axis of scleral fibers in inner and outer layers of highly myopic eyes were assessed, and the results were compared between eyes with and without a DSM.

Results

A total of 72 patients (51 [70.8%] female; mean [SD] age, 61.5 [12.8] years) were included, and 89 highly myopic eyes were examined (mean [SD] axial length, 30.4 [1.7] mm); 52 (58.4%) did not have a DSM and 37 (41.6%) had a DSM (10 bidirectional [27.0%] and 27 horizontal [73.0%]). Among the 52 eyes without DSM, the 13 eyes with simple high myopia had primarily inner sclera visible, displaying radially oriented fibers in optic axis images. In contrast, the entire thickness of the sclera was visible in 39 eyes with pathologic myopia. In these eyes, the optic axis images showed vertically oriented fibers within the outer sclera. Eyes presenting with both horizontal and bidirectional DSMs had clusters of fibers with low birefringence at the site of the DSM. In the optic axis images, horizontally or obliquely oriented scleral fibers were aggregated in the inner layer at the DSM. The vertical fibers located posterior to the inner fiber aggregation were not thickened and appeared thin compared with the surrounding areas.

Conclusions and Relevance

This study using PS-OCT revealed inner scleral fiber aggregation without outer scleral thickening at the site of the DSM in highly myopic eyes. Given the common occurrence of scleral pathologies, such as DSM, and staphylomas in eyes with pathologic myopia, recognizing these fiber patterns could be important. These insights may be relevant to developing targeted therapies to address scleral abnormalities early and, thus, mitigate potential damage to the overlying neural tissue.

Identification of key lncRNAs in age-related macular degeneration through integrated bioinformatics and experimental validation

This study aimed to identify key long noncoding RNAs (lncRNAs) in age-related macular degeneration (AMD) patients and to identify relevant pathological mechanisms of AMD development. We identified 407 differentially expressed mRNAs and 429 differentially expressed lncRNAs in retinal pigment epithelium (RPE) and retina in the macular region of AMD patients versus controls (P < 0.05 and |log2FC| > 0.585) from GSE135092. A total of 14 key differentially expressed mRNAs were obtained through external data validation from GSE115828. A miRNA-mRNA and miRNA-lncRNA network containing 52 lncRNA nodes, 49 miRNA nodes, 14 mRNA nodes and 351 edges was constructed via integrated analysis of these components. Finally, the LINC00276-miR-619-5p-IFIT3 axis was identified via protein-protein network analysis. In the t-BH-induced ARPE-19 senescent cell model, LINC00276 and IFIT3 were downregulated. Overexpression of LINC00276 could accelerate cell migration in combination with IFIT3 upregulation. This compelling finding suggests that LINC00276 plays an influential role in the progression of AMD, potentially through modulating senescence processes, thereby setting a foundation for future investigative efforts to verify this relationship.

Review: Mechanisms of TIMP-3 accumulation and pathogenesis in Sorsby fundus dystrophy

Sorsby fundus dystrophy (SFD) is a rare, inherited form of macular degeneration caused by mutations in the gene encoding tissue inhibitor of metalloproteinases 3 (TIMP-3). There are 21 mutations currently associated with SFD, with some variants (e.g., Ser179Cys, Tyr191Cys, and Ser204Cys) having been studied much more than others. We review what is currently known about the identified SFD variants in terms of their dimerization, metalloproteinase inhibition, and impact on angiogenesis, with a focus on disparities between reports and areas requiring further study. We also explore the potential molecular mechanisms leading to the accumulation of extracellular TIMP-3 in SFD and consider how accumulated TIMP-3 causes macular damage. Recent reports have identified extraocular pathologies in a small number of SFD patients. We discuss these intriguing findings and consider the apparent discrepancy between the widespread expression of TIMP-3 and the primarily retinal manifestations of SFD. The potential benefits of novel experimental approaches (e.g., metabolomics and stem cell models) in terms of investigating SFD pathology are presented. The review thus highlights gaps in our current molecular understanding of SFD and suggests ways to support the development of novel therapies.

Macular lesions associated with age-related macular degeneration in pachydrusen eyes

BACKGROUND

To investigate the prevalence of macular lesions associated with age-related macular degeneration (AMD) in eyes with pachydrusen.

METHODS

Clinical records and multimodal imaging data of patients over 50 years old with drusen or drusenoid deposits were retrospectively assessed, and eyes with pachydrusen were included in this study. The presence of AMD features, including drusen or drusenoid deposits, macular pigmentary abnormalities, geographic atrophy (GA), and macular neovascularization (MNV), were evaluated.

RESULTS

Out of 967 eyes of 494 patients with drusen or drusenoid deposits, 330 eyes of 183 patients had pachydrusen (34.1%). The mean age was 66.1 ± 9.3 years, and the subfoveal choroidal thickness (SFCT) was 292.7 ± 100.1 μm. The mean number of pachydrusen per eye was 2.22 ± 1.73. The majority of eyes with pachydrusen had no other drusen or drusenoid deposits (95.2%). Only 16 eyes (4.8%) had other deposits, including soft drusen (10 eyes, 3.0%), cuticular drusen (3 eyes, 0.9%), and reticular pseudodrusen (RPD; 3 eyes, 0.9%). Macular pigmentary abnormalities accompanied pachydrusen in 68 eyes (27.4%). None of the eyes had GA, and 82 eyes (24.8%) had MNV. The majority of MNV was polypoidal choroidal vasculopathy (PCV; 65 eyes, 19.7%), followed by type 1 (10 eyes, 3.0%), type 2 (5 eyes, 1.5%), and type 3 MNV (2 eyes, 0.6%).

CONCLUSIONS

Eyes with pachydrusen in Korean population have several characteristic AMD lesions in low frequencies. These findings indicate that pachydrusen might have diagnostic and prognostic values that are different from those of other drusen or drusenoid deposits.

PARACENTRAL ACUTE MIDDLE MACULOPATHY WITH SICKLE CELL TRAIT

PURPOSE

To report a case of paracentral acute middle maculopathy in a pediatric patient with sickle cell trait.

METHODS

The patient was evaluated with a comprehensive ophthalmic examination, optical coherence tomography, optical coherence tomography angiography, and fluorescein angiography.

RESULTS

Acute loss of vision occurred immediately after an uneventful scleral buckling procedure for retinal detachment in a 16-year-old female patient. Retinal imaging studies confirmed the occurrence of paracentral acute middle maculopathy, an ischemic condition characterized by infarction of the inner nuclear layer of the retina caused by hypoperfusion of the intermediate and deep capillary plexuses. Laboratory evaluation was only remarkable for sickle cell trait. Over a course of 3 months after the loss of vision, visual acuity improved from 20/1,000 to 20/20, and optical coherence tomography lesion resolved to a parafoveal area of inner and middle retinal layer thinning. Paracentral scotoma corresponding to the atrophic area persisted.

CONCLUSION

Dehydration because of the presurgical nil-per-os status and transient increase in intraocular pressure during the buckling surgery may have predisposed this patient with sickle cell trait to a sickling event that caused localized ischemia in the middle retina's end-capillaries. Avoiding long nil-per-os status, being mindful of transient intraocular pressure elevation during scleral buckling procedures, and presurgical hemoglobin electrophoresis in at-risk populations are recommended to prevent sickling attacks during retinal surgeries in individuals with sickle cell trait.

Incidence and multimodal imaging characteristics of macular neovascularisation subtypes in Chinese neovascular age-related macular degeneration patients

AIMS

To investigate the incidence of macular neovascularisation (MNV) subtypes of neovascular age-related macular degeneration (nAMD) and summarise these subtypes' clinical features in the Chinese population using multimodal imaging.

METHODS

We retrospectively analysed 506 consecutive treatment-naïve nAMD patients (582 eyes). Incidence of MNV subtypes and clinical features were recorded based on their multimodal images. The classification of MNV subtypes in nAMD patients were referred to Consensus on Neovascular Age-related Macular Degeneration Nonmenclature (CONAN) study group classifications.

RESULTS

460 eyes of 389 nAMD patients were included in our study. 68.5% (315/460) of nAMD eyes were from male. According to CONAN, we identified type 1 macular neovascularisation (MNV) in 61.1% of eyes (281/460), type 2 MNV in 16.3% of eyes (75/460), type 3 MNV in 2.0% of eyes (9/460), mixed type 1 and type 2 MNV in 20.6% of eyes (95/460). 58% of eyes (267/460) were diagnosed as polypoidal choroidal vasculopathy lesions (PCV). 45.2% of eyes (208/460) with PCV lesions were type 1 MNV and 12.8% of eyes (59/460) with PCV lesions were co-occurred with type 2 MNV.

CONCLUSION

Based on the consensus anatomical classification system developed by the CONAN Study Group, we updated the incidence of MNV subtypes and found that PCV was the most common subtype and type 3 MNV was the least common subtype among Chinese nAMD patients. In addition, the co-occurrence of PCV and type 2 MNV was typically observed, and its frequency was reported in our study.

Optimizing the sodium iodate model: Effects of dose, gender, and age

Sodium iodate (NaIO3) is a commonly used model for age-related macular degeneration (AMD), but its rapid and severe induction of retinal pigment epithelial (RPE) and photoreceptor degeneration can lead to the premature dismissal of potentially effective therapeutics. Additionally, little is known about how sex and age affect the retinal response to NaIO3. This study aims to establish a less severe yet reproducible regimen by testing low doses of NaIO3 while considering age- and sex-related effects, enabling a broader range of therapeutic evaluations. In this study, young (3-5 months) and old (18-24 months) male and female C57Bl/6J mice were given an intraperitoneal (IP) injection of 15, 20, or 25 mg/kg NaIO3. Damage assessment one week post-injection included in vivo imaging, histological examination, and qRT-PCR analysis. The results revealed that young mice showed no damage at 15 mg/kg IP NaIO3, with varying degrees of damage observed at 20 mg/kg. At 25 mg/kg, most young mice displayed widespread retinal damage, with females exhibiting less retinal thinning than males. In contrast, older mice at 20 and 25 mg/kg displayed a more patchy degeneration pattern, outer retinal undulations, and greater variability in degeneration than the young mice. The most effective model for minimizing damage while maintaining consistency utilizes young female mice injected with 25 mg/kg NaIO3. The observed sex- and age-related differences underscore the importance of considering these variables in research, aligning with the National Institutes of Health's guidance. While the model does not fully replicate the complexity of AMD, these findings enhance its utility as a valuable tool for testing RPE/photoreceptor protective or replacement therapies.

Role of immune inflammation regulated by macrophage in the pathogenesis of age-related macular degeneration

Age-related macular degeneration (AMD) can lead to irreversible impairment of visual function, and the number of patients with AMD has been increasing globally. The immunoinflammatory theory is an important pathogenic mechanism of AMD, with macrophages serving as the primary inflammatory infiltrating cells in AMD lesions. Its powerful immunoinflammatory regulatory function has attracted considerable attention. Herein, we provide an overview of the involvement of macrophage-regulated immunoinflammation in different stages of AMD. Additionally, we summarize novel therapeutic approaches for AMD, focusing on targeting macrophages, such as macrophage/microglia modulators, reduction of macrophage aggregation in the subretinal space, modulation of macrophage effector function, macrophage phenotypic alterations, and novel biomimetic nanocomposites development based on macrophage-associated functional properties. We aimed to provide a basis and reference for the further exploration of AMD pathogenesis, developmental influences, and new therapeutic approaches.

CRISPR Manipulation of Age-Related Macular Degeneration Haplotypes in the Complement System: Potential Future Therapeutic Applications/Avenues

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss among the elderly in the developed world. Whilst AMD is a multifactorial disease, the involvement of the complement system in its pathology is well documented, with single-nucleotide polymorphisms (SNPs) in different complement genes representing an increased risk factor. With several complement inhibitors explored in clinical trials showing limited success, patients with AMD are still without a reliable treatment option. This indicates that there is still a gap of knowledge in the functional implications and manipulation of the complement system in AMD, hindering the progress towards translational treatments. Since the discovery of the CRISPR/Cas system and its development into a powerful genome engineering tool, the field of molecular biology has been revolutionised. Genetic variants in the complement system have long been associated with an increased risk of AMD, and a variety of haplotypes have been identified to be predisposing/protective, with variation in complement genes believed to be the trigger for dysregulation of the cascade leading to inflammation. AMD-haplotypes (SNPs) alter specific aspects of the activation and regulation of the complement cascade, providing valuable insights into the pathogenic mechanisms of AMD with important diagnostic and therapeutic implications. The effect of targeting these AMD-related SNPs on the regulation of the complement cascade has been poorly explored, and the CRISPR/Cas system provides an ideal tool with which to explore this avenue. Current research concentrates on the association events of specific AMD-related SNPs in complement genes without looking into the effect of targeting these SNPs and therefore influencing the complement system in AMD pathogenesis. This review will explore the current understanding of manipulating the complement system in AMD pathogenesis utilising the genomic manipulation powers of the CRISPR/Cas systems. A number of AMD-related SNPs in different complement factor genes will be explored, with a particular emphasis on factor H (CFH), factor B (CFB), and complement C3 (C3).

Long-term follow-up of torpedo maculopathy: a case series and mini-review

BACKGROUND

Torpedo maculopathy (TM) is a rare, congenital condition characterized by an oval-shaped, chorioretinal lesion in the temporal macula of unknown etiology. To our knowledge, the longest reported follow-up of TM is 5 years. Herein we report 10 years of follow-up on two patients with TM to further characterize the long-term natural history of the condition.

CASE REPORTS

Two patients with torpedo maculopathy were examined at baseline and then again at 5 years and 10 years from baseline. Eyes were evaluated using color fundus photography, automated perimetry, fundus autofluorescence and spectral domain optical coherence tomography. Visual function of both patients remained stable throughout the observation period. In case 1, there was no evidence of change in lesion morphology over the 10 year observation period. Case 2 showed progression of cystic degeneration of the neurosensory retina within the torpedo lesion. Case 1 reported a history of supernumerary teeth and underwent gene sequence with deletion/duplication analyses of the APC gene but no clinically significant variants were detected.

CONCLUSIONS

Our findings support the position that TM is a nonprogressive condition with long-term stability of visual function. Genetic analysis of case 1 failed to detect any association with Gardner syndrome.

Chemokine Receptor Profile of T Cells and Progression Rate of Geographic Atrophy Secondary to Age-related Macular Degeneration

Purpose

Geographic atrophy (GA) secondary to age-related macular degeneration is a progressive retinal degenerative disease. Systemic chemokine receptors and known risk-associated single-nucleotide polymorphisms have been associated with GA pathogenesis. Because halting progression is pivotal for patients, we investigated the association of candidate chemokine receptors and progression rate (PR) of atrophic lesions in patients with GA.

Methods

This prospective observational study conducted at a single center included 85 patients with GA and 45 healthy controls. Patients were followed up after 13 months on average. Serial fundus autofluorescence images were used to determine the PR of atrophic lesions. The proportion of chemokine receptors on peripheral lymphocytes were determined by flow cytometric analysis.

Results

Patients with GA had a lower proportion of CCR6 on CD8+T cells compared to healthy controls. Importantly, the proportion of CCR6 on CD4+T cells was lower in patients with fast GA progression compared to patients with slow progression of disease, suggesting that dysregulation of CCR6 could be involved in progression of GA. We also found that GA patients had a markedly higher percentage of CCR5 on CD4+ and CD8+T cells compared to healthy controls. After stratification according to ARMS2 polymorphism, we found a significantly lower level of CCR5 on CD8+T cells among patients with high-risk genotypes compared with patients with the low-risk genotype.

Conclusions

Our study finds that chemokine receptors are dysregulated in patients with GA and that CCR6 might be involved in GA progression, making it a potential target for intervention.

Clinical and multimodal imaging findings in a case of serous maculopathy with absence of retinal pigment epithelium (SMARPE)

INTRODUCTION

The differential diagnosis for serous SRF can involve diseases with widely different pathogenic mechanisms that can range from vascular ocular diseases to ocular tumours and paraneoplastic syndromes. Recently, van Dijk et al. have described in three patients a new entity which they have called serous maculopathy with an absence of retinal pigment epithelium (SMARPE). We hereby describe a case of this infrequent macular disease and report its characteristic findings on multimodal imaging.

CASE DESCRIPTION

We present the case of a 65-year-old hyperopic woman with a three-year history of visual acuity (VA) loss in her left eye. Prior optical coherence tomography (OCT) had revealed the presence of serous subretinal fluid that had shown no response to treatment with intravitreal injections. On swept source OCT angiography scan, no macular alterations in the retinal vascular plexus structure were noted and there was no evidence of choroidal neovascularization. Ultra-widefield fluorescence angiography of the left eye revealed an early hyperfluorescent macular spot corresponding to the area of absent RPE and late fluorescein pooling. On ultra-widefield indocyanine green angiography there were no central or peripheral abnormalities of choroidal vascularization.

CONCLUSION

This recently described entity should be considered as a differential diagnosis in persistent serous subretinal fluid. Multimodal imaging helps differentiate SMARPE from its main differential diagnoses, and care should be taken to identify and differentiate it from similar conditions to avoid unnecessary treatment with its possible side effects and complications.

PREVALENCE AND PERSISTENCE OF HYPERTRANSMISSION DEFECTS OF VARIOUS SIZES IN EYES WITH INTERMEDIATE AGE-RELATED MACULAR DEGENERATION

PURPOSE

To determine the prevalence and rate of persistence over 2 years of various-sized hypertransmission defects (hyperTDs) in eyes with intermediate age-related macular degeneration.

METHODS

Retrospective analysis of optical coherence tomography data from consecutive intermediate age-related macular degeneration patients. Choroidal en face optical coherence tomography images were evaluated for the presence and number of hyperTDs of three different sizes based on greatest linear dimension (small, 63-124 µ m; medium, 125-249 µ m; large, ≥250 µ m) at baseline and at the 2-year follow-up. Interreader agreement was determined by Gwet's agreement coefficient. Disagreements between graders were resolved by the senior investigator to yield a single consensus for all cases.

RESULTS

From 273 intermediate age-related macular degeneration eyes (247 patients), 72 and 76 hyperTD lesions were independently identified by two graders at baseline and overall agreement coefficient was 0.89 (95% CI, 0.86-0.93). After adjudication by the senior grader, the final consensus yielded 78 hyperTD lesions from 46 eyes (16.8%) of 42 patients (17.0%) in this study cohort. Among eyes with follow-up optical coherence tomography, 32 of 45 hyperTD lesions (71.1%) persisted. The rates of persistence were 100.0%, 72.7%, and 53.3% in large, medium, and small hyperTD sizes, respectively.

CONCLUSION

HyperTDs were present in a significant proportion of intermediate age-related macular degeneration eyes. Acceptable interreader agreement was demonstrated in identifying hyperTD. Larger hyperTD lesions were more likely to persist over 2 years.

MULTIMODAL RETINAL IMAGING REVEALS NEW PATHOGENIC INSIGHTS IN CENTRAL AREOLAR CHOROIDAL DYSTROPHY: A CASE SERIES

PURPOSE

To describe novel imaging findings in a family affected by central areolar choroidal dystrophy.

METHODS

Case series with multimodal retinal imaging assessment.

RESULTS

A 19-year-old asymptomatic woman was referred for bilateral macular defects of the retinal pigment epithelium. Blue-light autofluorescence of her right eye revealed a speckled pattern in the macular area with a ring of decreased autofluorescence using near-infrared autofluorescence. Multimodal assessment of her left eye disclosed a single parafoveal spot of decreased pigmentation that was clearly visible as hyperautofluorescent using blue-light autofluorescence and as hypoautofluorescent using near-infrared autofluorescence. Optical coherence tomography angiography revealed several tiny areas of flow voids in correspondence of the retinal pigment epithelium alterations of both eyes. Three family members were recently diagnosed with presumed age-related macular degeneration and demonstrated well-demarcated areas of retinal pigment epithelium atrophy surrounded by yellowish deposits and a hypopigmented halo. Next-generation genetic analysis for inherited macular dystrophies was performed on the index case and the affected family members and revealed a p.Arg172Gln missense mutation in PRPH2 gene, leading to the diagnosis of central areolar choroidal dystrophy.

CONCLUSION

Multimodal imaging can reveal new pathogenic insights in central areolar choroidal dystrophy. Of notice, near-infrared autofluorescence and optical coherence tomography angiography are able to detect retinal pigment epithelium hypopigmentation and choriocapillaris rarefaction, respectively, since the earliest stages of the disease.

Optical Coherence Tomography Features of Macular Hyperpigmented Lesions without Intraretinal Hyperreflective Foci in Age-Related Macular Degeneration

PURPOSE

To evaluate the optical coherence tomography (OCT) features of hyperpigmented lesions in the absence of intraretinal hyperreflective foci (IHRF) on OCT in eyes with age-related macular degeneration (AMD).

METHODS

We retrospectively analyzed OCT images of eyes with intermediate AMD (iAMD) and macular hyperpigmentation (HP) on color fundus photograph (CFP) but without IHRF on OCT in the corresponding location. The most prominent or definite HP was selected for analysis. The infrared reflectance (IR) image registered with the CFP, and the location corresponding to the HP lesion were defined on the IR image. The location of the HP on the corresponding OCT B-scan was assessed for retinal pigment epithelium (RPE) elevation, acquired vitelliform lesion (AVL), abnormal retinal pigment epithelium + basal lamina (RPE + BL) band reflectivity, RPE + BL band thickening, as well as interdigitation zone (IZ), ellipsoid zone (EZ) and external limiting membrane (ELM) disruption.

RESULTS

49 eyes (39 patients) were included in this study. Forty-six (94%) of the hyperpigmented lesions showed a thickened RPE + BL band. RPE + BL band reflectivity was increased in 37 (76%) of the lesions. RPE + BL band thickening, however, was not correlated with RPE + BL band reflectivity (p-value = 0.31). Either thickening or hyperreflectivity of the RPE + BL band was present in all cases. Twenty (41%) lesions had evidence of ELM disruption, 42 (86%) demonstrated EZ disruption and 48 (98%) had IZ disruption. Five (10%) HPs demonstrated AVL. Among cases with RPE elevation (15 cases, 31%), 10 were classified as drusen, 2 as drusenoid PEDs, and 3 as fibrovascular PEDs.

CONCLUSIONS

Thickening and/or hyperreflectivity of the RPE + BL band commonly correspond to regions of macular hyperpigmentation without IHRF in eyes with iAMD.

Association of torpedo maculopathy and keratoconus in a young patient: A multimodal imaging study

PURPOSE

To report and document a case of torpedo maculopathy found in a patient affected by keratoconus.Case report: An healthy 16-year-old male patient, affected by keratoconus in both eyes, was referred to the cornea service of our hospital for a follow-up visit.During the dilated fundus examination of the left eye, an oval, well-demarcated, hypopigmented lesion was observed in the juxtafoveal temporal region, pointing towards the center of the macula. Multimodal imaging of the lesion was performed, and the diagnosis of Torpedo Maculopathy was established based on the clinical picture.

CONCLUSION

This is the first case of torpedo maculopathy described in a patient affected by keratoconus. This association may be merely fortuitous or the result of developmental abnormalities affecting both corneal and retinal structures.

PARACENTRAL ACUTE MIDDLE MACULOPATHY ASSOCIATED WITH SEVERE PLASMODIUM FALCIPARUM MALARIA

PURPOSE

To report a case of bilateral paracentral acute middle maculopathy lesions on spectral domain-optical coherence tomography(OCT) secondary to severe Plasmodium falciparum malaria.

METHODS

Retrospective case report. Spectral domain-OCT, ultra-widefield fluorescein angiography, and OCT angiography were performed and analyzed.

RESULTS

A 54-year-old healthy man presented with acute vision loss in both eyes few days after being diagnosed with severe Plasmodium falciparum malaria. Ophthalmoscopic examination was unremarkable, but near-infrared reflectance imaging showed patchy hyporeflective areas located at the terminal tips of the venous branches. Corresponding spectral-domain OCT demonstrated alternating bands of hyperreflectivity involving the inner nuclear layer, consistent with skip paracentral acute middle maculopathy lesions. Optical coherance tomography angiography illustrated corresponding flow signal loss at the level of the deep capillary plexus. Ultra-widefield fluorescein angiography showed peripheral retinal vein staining and capillary nonperfusion.

CONCLUSION

Paracentral acute middle maculopathy may be an OCT manifestation of malarial retinopathy associated with severe Plasmodium falciparum infection.

Drusen and Other Retinal Findings in People With IgA Glomerulonephritis

PURPOSE

Retinal drusen have been described in people with IgA nephropathy. We examined the frequency of drusen in IgA nephropathy and compared their location and composition with those for drusen in age-related macular degeneration.

DESIGN

Immunohistological case series of eyes of patients with IgA nephropathy, and a comparison eye with age-related macular degeneration.

METHODS

Donor eyes from 4 individuals (3 male, 1 female, aged 40-80 years) with biopsy-proven IgA nephropathy and kidney failure were examined for the presence of drusen, and location and composition using antibodies for vitronectin, IgA, IgM, IgG, C3, and C1q. Results were compared with those for drusen in macular degeneration without IgA nephropathy.

RESULTS

All 4 donors had sparse, subretinal pigment epithelium drusen of 55-65 mm diameter that stained for vitronectin but not for IgA or complement. All donors had retinal capillaries and choriocapillaris staining for IgA. The youngest donor (female, 40) had rare deposits in the outer nuclear layer that stained for IgA, but not for vitronectin. The oldest donor (male, 82) had large cystlike spaces in the inner nuclear and plexiform layers, and smaller cysts in the outer nuclear layer, with no staining for IgA or complement.

CONCLUSIONS

Retinal drusen are uncommon in IgA nephropathy, even with kidney failure. Drusen in IgA nephropathy resemble drusen found in age-related macular degeneration. IgA-staining deposits in the outer nuclear layer were likely due to systemic deposition of IgA and complement activation. The nature of cystic spaces is unknown. Further analysis of the retinas of people with glomerulonephritis is recommended.

Effects of Humanin G (HNG) on angiogenesis and neurodegeneration markers in Age-related Macular Degeneration (AMD)

Advanced stages of Age-related Macular Degeneration (AMD) are characterized by retinal neurodegeneration and aberrant angiogenesis, and mitochondrial dysfunction contributes to the pathogenesis of AMD. In this study, we tested the hypothesis that Humanin G (HNG), a cytoprotective mitochondrial-derived peptide, positively regulates cell proliferation, cell death, and the protein levels of angiogenesis and neurodegeneration markers, in normal (control) and AMD RPE transmitochondrial cybrid cell lines. These normal and AMD RPE transmitochondrial cybrid cell lines had identical nuclei derived from mitochondria-deficient ARPE-19 cell line, but differed in mitochondrial DNA (mtDNA) content that was derived from clinically characterized AMD patients and normal (control) subjects. Cell lysates were extracted from untreated and HNG-treated AMD and normal (control) cybrid cell lines, and the Luminex XMAP multiplex assay was used to examine the protein levels of angiogenesis and neurodegeneration markers. Humanin G reduced Caspase-3/7-mediated apoptosis, improved cell proliferation, and normalized the protein levels of angiogenesis and neurodegeneration markers in AMD RPE cybrid cell lines, thereby suggesting Humanin G's positive regulatory role in AMD.

A rare case of hyperpigmented torpedo maculopathy

PURPOSE

To describe a rare presentation of torpedo maculopathy (TM).

CASE DESCRIPTION

A 25-year-old male was examined in the retina clinic for a macular scar in the left eye. His visual acuity was 20/20, N6 in both eyes and no past history of ocular trauma or any medical or ocular history. The anterior segment was quiet and intraocular pressure was normal.

RESULTS

The patient's left eye on 78D slit lamp biomicroscopy revealed a flat, diffusely hyperpigmented fusiform torpedo-like lesion with sharp margins and surrounding hypopigmentation located predominantly temporal to the fovea, with its tip pointing towards it and just crossing the vertical foveal midline. Dilated fundus examination with binocular indirect ophthalmoscopy revealed no peripheral chorioretinal lesions or vitritis in both eyes. OCT scan through the lesion revealed gross damage to the outer retinal layers, as well as thickening of the retinal pigment epithelium and underlying shadowing, as well as a hyporeflective subretinal cleft involving the lesion. OCT also revealed outer retinal layer damage with an intact retinal pigment epithelium through the lesion's hypopigmented margins. Fundus autofluorescence image revealed a globally hypoautofluorescent lesion in the left eye, with surrounding patchy hyperautofluoroscent areas. Based on the patient history, clinical and imaging findings, other differential diagnoses such as atypical congenital hypertrophy of retinal pigment epithelium (RPE), choroidal nevus, RPE hamartoma, trauma and inflammatory conditions were ruled out. The diagnosis of TM was confirmed based on the typical lesion shape and location.

CONCLUSION

A torpedo lesion with diffuse hyperpigmentation is an unusually rare presentation.

Effects of donor-specific microvascular anatomy on hemodynamic perfusion in human choriocapillaris

Evidence from histopathology and clinical imaging suggest that choroidal anatomy and hemodynamic perfusion are among the earliest changes in retinal diseases such as age-related macular degeneration (AMD). However, how inner choroidal anatomy affects hemodynamic perfusion is not well understood. Therefore, we sought to understand the influences of choroidal microvascular architecture on the spatial distribution of hemodynamic parameters in choriocapillaris from human donor eyes using image-based computational hemodynamic (ICH) simulations. We subjected image-based inner choroid reconstructions from eight human donor eyes to ICH simulation using a kinetic-based volumetric lattice Boltzmann method to compute hemodynamic distributions of velocity, pressure, and endothelial shear stress. Here, we demonstrate that anatomic parameters, including arteriolar and venular arrangements and intercapillary pillar density and distribution exert profound influences on inner choroidal hemodynamic characteristics. Reductions in capillary, arteriolar, and venular density not only reduce the overall blood velocity within choriocapillaris, but also substantially increase its spatial heterogeneity. These first-ever findings improve understanding of how choroidal anatomy affects hemodynamics and may contribute to pathogenesis of retinal diseases such as AMD.

Interleukin-17-mediated protective cytokine signaling against degeneration of the retinal pigment epithelium

Injuries to the retinal pigment epithelium (RPE) and outer retina often result in the accumulation of retinal microglia within the subretinal space. These subretinal microglia play crucial roles in inflammation and resolution, but the mechanisms governing their functions are still largely unknown. Our previous research highlighted the protective functions of choroidal γδ T cells in response to RPE injury. In the current study, we employed single-cell RNA sequencing approach to characterize the profiles of immune cells in mouse choroid. We found that γδ T cells were the primary producer of interleukin-17 (IL-17) in the choroid. IL-17 signaled through its receptor on the RPE, subsequently triggering the production of interleukin-6. This cascade of cytokines initiated a metabolic reprogramming of subretinal microglia, enhancing their capacity for lipid metabolism. RPE-specific knockout of IL-17 receptor A led to the dysfunction of subretinal microglia and RPE pathology. Collectively, our findings suggest that responding to RPE injury, the choroidal γδ T cells can initiate a protective signaling cascade that ensures the proper functioning of subretinal microglia.

Conditional loss of Ube3d in the retinal pigment epithelium accelerates age-associated alterations in the retina of mice

Several studies have suggested a correlation between the ubiquitin-proteasome system (UPS) and age-related macular degeneration (AMD), with its phenotypic severity ranging from mild visual impairment to blindness, but the mechanism for UPS dysfunction contributing to disease progression is unclear. In this study, we investigated the role of ubiquitin protein ligase E3D (UBE3D) in aging and degeneration in mouse retina. Conditional knockout of Ube3d in the retinal pigment epithelium (RPE) of mice led to progressive and irregular fundus lesions, attenuation of the retinal vascular system, and age-associated deterioration of rod and cone responses. Simultaneously, RPE-specific Ube3d knockout mice also presented morphological changes similar to the histopathological characteristics of human AMD, in which a defective UPS led to RPE abnormalities such as phagocytosis or degradation of metabolites, the interaction with photoreceptor outer segment, and the transport of nutrients or waste products with choroidal capillaries via Bruch's membrane. Moreover, conditional loss of Ube3d resulted in aberrant molecular characterizations associated with the autophagy-lysosomal pathway, oxidative stress damage, and cell-cycle regulation, which are implicated in AMD pathology. Thus, our findings strengthen and expand the impact of UPS dysfunction on retinal pathophysiology during aging, indicating that genetic Ube3d deficiency in the RPE could lead to the abnormal formation of pigment deposits and secondary fundus alterations. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Generation of an iPSC line (RMCGENi020-A) from a patient with Stargardt disease harboring the recurrent intronic ABCA4 variant c.4253+43G>A

Pathogenic variants in ABCA4 are associated with Stargardt disease (STGD1), an autosomal recessive macular dystrophy characterized by bilateral central vision loss due to a progressive degeneration of retinal cells. An induced pluripotent stem cell (iPSC) line was generated from late-onset STGD1 patient-derived fibroblasts harboring bi-allelic ABCA4 variants by lentivirus-induced reprogramming. The obtained iPSC line (RMCGENi020-A) showed pluripotent features after the reprogramming process. The generation of this iPSC line facilitates its use to differentiate it into relevant retinal-like cell models, with the aim to adequately evaluate the effects of the ABCA4 variants.

Interreader Agreement and Longitudinal Progression of Incomplete/Complete Retinal Pigment Epithelium and Outer Retinal Atrophy in Age-Related Macular Degeneration

OBJECTIVE

To analyze the ability to evaluate changes over time of individual lesions of incomplete or complete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA and cRORA, respectively) in patients with intermediate age-related macular degeneration (iAMD).

DESIGN

OCT images from patients enrolled in Proxima B clinical trial (NCT02399072) were utilized.

PARTICIPANTS

Patients enrolled in the Proxima B clinical trial, from the cohort with geographic atrophy (GA) in 1 eye and iAMD in the other eye at baseline, were included.

METHODS

Junior and senior readers analyzed OCT images for the qualitative presence of 9 distinct early atrophic features (presence of zone of choroidal hypertransmission, attenuation and/or disruption of RPE, disruption of ellipsoid zone [EZ] and external limiting membrane [ELM], outer nuclear layer [ONL] thinning, outer plexiform layer [OPL]/inner nuclear layer [INL] subsidence, and hyporeflective wedge-shaped band). If deemed "present," 7 features were quantified with a predefined tolerance level of 50 μm (diameter for the zone of choroidal hypertransmission, zone of attenuation and/or disruption of the RPE, outer retinal thickness left/right vertical diameter, outer retinal thickness thinnest vertical diameter, annotation of EZ, and ELM disruption).

MAIN OUTCOME MEASURES

Interreader agreements for qualitative assessments (κ-type statistics) and quantitative measurements (Bland-Altman statistics) were assessed. Progression of the lesion features over time was described.

RESULTS

Moderate agreement was found for presence of choroidal hypertransmission (κ = 0.54), followed by ELM disruption (κ = 0.58), OPL/INL subsidence (κ = 0.46), and a hyporeflective wedge-shaped band (κ = 0.47). Quantification measurements showed that choroidal hypertransmission had the highest agreement, whereas RPE attenuation/disruption had the lowest agreement. Longitudinal adjudicated changes for quantitative measurements of lesion progression showed that choroidal hypertransmission and ELM disruption showed significant progression, whereas EZ disruption and RPE attenuation/disruption did not.

CONCLUSIONS

The ability to evaluate changes over time for specific features of iRORA and cRORA was explored. The most robust biomarker was found to be choroidal hypertransmission, followed by ELM disruption and the qualitative markers of OPL/INL subsidence, as well as a wedge-shaped band. Disease progression over time could be assessed by some, but not all, spectral-domain OCT features that were explored.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Co-cultivation of primary porcine RPE cells and neuroretina induces inflammation: a potential inflammatory AMD-model

One common aspect in the pathology of many retinal diseases like age-related macular degeneration (AMD) is the death of retinal pigment epithelium (RPE) cells. RPE cells are essential for photoreceptor survival as they recycle and remove compounds of the visual cycle and secrete protective cytokines. Studying RPE cells is crucial to improve our understanding of retinal pathologies, yet only a few retinal ex vivo models include them or do so only indirectly. Besides the positive effects in indirect co-cultivation models, also a slight inflammation was observed. In this study we developed an ex vivo model consisting of a primary porcine RPE monolayer directly co-cultured with porcine retinal organ cultures, to investigate and simulate inflammatory retinal diseases, such as (dry) AMD. The direct co-cultivation resulted in immune reactivity (enhanced expression of pro-inflammatory cytokines e.g., IL-1β, IL-6, IL-8) and cell death. These effects were evaluated for the retinal explant as well as for the RPE-monolayer to further understand the complex interactions between these two compartments. Taken together, this ex vivo model can be used to study inflammatory retinal diseases like AMD as well as the rejection observed after RPE-transplantation.

Preclinical evaluation of KH631, a novel rAAV8 gene therapy product for neovascular age-related macular degeneration

The upregulation of vascular endothelial growth factor (VEGF) is strongly associated with the development of choroidal neovascularization (CNV) in patients with neovascular age-related macular degeneration (nAMD). Currently, the standard treatment for nAMD involves frequent intravitreal injections of anti-VEGF agents, which inhibit the growth of new blood vessels and prevent leakage. However, this treatment regimen places a significant burden on patients, their families, and healthcare providers due to the need for repeated visits to the clinic for injections. Gene therapy, which enables the sustained expression of anti-VEGF proteins after a single injection, can dramatically reduce the treatment burden. KH631 is a recombinant adeno-associated virus 8 vector that encodes a human VEGF receptor fusion protein, and it is being developed as a long-term treatment for nAMD. In preclinical studies using non-human primates, subretinal administration of KH631 at a low dose of 3 × 108 vg/eye resulted in remarkable retention of the transgene product in the retina and prevented the formation and progression of grade IV CNV lesions. Furthermore, sustained transgene expression was observed for more than 96 weeks. These findings suggest that a single subretinal injection of KH631 has the potential to offer a one-time, low-dose treatment for nAMD patients.

Red Light-Triggered Anti-Angiogenic and Photodynamic Combination Therapy of Age-Related Macular Degeneration

Choroidal neovascularization (CNV) is the key pathological event of wet age-related macular degeneration (wAMD) leading to irreversible vision loss. Currently, anti-angiogenic therapy with anti-vascular endothelial growth factor (VEGF) agents has become the standard treatment for wAMD, while it is still subject to several limitations, including the safety concerns of monthly intravitreal administration and insufficient efficacy for neovascular occlusion. Combined therapy with photodynamic therapy (PDT) and anti-angiogenic agents has emerged as a novel treatment paradigm. Herein, a novel and less-invasive approach is reported to achieve anti-angiogenic and photodynamic combination therapy of wAMD by intravenous administration of a photoactivatable nanosystem (Di-DAS-VER NPs). The nanosystem is self-assembled by reactive oxygen species (ROS)-sensitive dasatinib (DAS) prodrug and photosensitizer verteporfin (VER). After red-light irradiation to the diseased eyes, intraocular release of anti-angiogenic DAS is observed, together with selective neo-vessels occlusion by VER-generated ROS. Notably, Di-DAS-VER NPs demonstrates promising therapeutic efficacy against CNV with minimized systemic toxicity. The study enables an efficient intravenous wAMD therapy by integrating a photoactivation process with combinational therapeutics into one simple nanosystem.

Transcriptomic and Chromatin Accessibility Analysis of the Human Macular and Peripheral Retinal Pigment Epithelium at the Single-Cell Level

Some human retinal diseases are characterized by pathology that is restricted to specific cell types and to specific regions of the eye. Several disease entities either selectively affect or spare the macula, the retina region at the center of the posterior pole. Photoreceptor cells in the macula are involved in high-acuity vision and require metabolic support from non-neuronal cell types. Some macular diseases involve the retinal pigment epithelium (RPE), an epithelial cell layer with several metabolic-support functions essential for the overlying photoreceptors. In the current study, the ways in which RPE confers region-specific disease susceptibility were determined by examining heterogeneity within RPE tissue from human donors. RPE nuclei from the macular and peripheral retina were profiled using joint single-nucleus RNA and ATAC sequencing. The expression of several genes differed between macular and peripheral RPE. Region-specific ATAC peaks were found, suggesting regulatory elements used exclusively by macular or peripheral RPE. Across anatomic regions, subpopulations of RPE were identified that appeared to have differential levels of expression of visual cycle genes. Finally, loci associated with age-related macular degeneration were examined for a better understanding of RPE-specific disease phenotypes. These findings showed variations in the regulation of gene expression in the human RPE by region and subpopulation, and provide a source for a better understanding of the molecular basis of macular disease.