Pigment Epithelium Research Articles

Atorvastatin Alleviates Age-Related Macular Degeneration via AIM2-Regulated Pyroptosis.

The underlying causes of age-related macular degeneration (AMD) remain elusive and treatment options of it are limited, while atorvastatin (AT) is expected to improve AMD. Our study sought to uncover the specific mechanisms that initiate pyroptosis in AMD and elucidate whether AT ameliorates Aβ1-40-induced retinal damage by inhibiting pyroptosis. An animal model of AMD was triggered by Aβ1-40, and the therapeutic efficacy of AT was evaluated by hematoxylin and eosin staining (H&E), Optical Coherence Tomography (OCT), Electroretinogram (ERG) and other methods. Utilizing network pharmacology in conjunction with transcriptomics, we identified potential therapeutic pathways. we employed Western blotting (WB) and quantitative real-time PCR (qPCR) methodologies to evaluate the levels of pyroptosis. In vitro system of retinal pigment epithelium (RPE) cells injury was caused by Aβ1-40 and subsequently treated with AT or JC2-11. The extent of pyroptosis was quantified using enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining and WB. Cell morphological changes were examined using light microscopy and scanning electron microscopy. Network pharmacology and transcriptomics identified AIM2/Caspase-1/GSDMD as the key pathway. AT improved the retinal morphological and functional damage caused by Aβ1-40, and decreased the production of AIM2, Asc, Caspase-1, GSDMD-N, Cleaved Caspase-1 and cytokines to exert an anti-inflammatory effect. In addition, AT improved the ruptured membrane of RPE cells caused by Aβ1-40. The use of JC2-11 further demonstrated that AT inhibits pyroptosis of RPE via AIM2/Caspase-1/GSDMD pathway activated by Aβ1-40. These discoveries illuminate the retinal conservation role of AT by effectively hindering the progression of pyroptosis.

Identifying retinal pigment epithelium cells in adaptive optics–optical coherence tomography images with partial annotations and superhuman accuracy

Identifying retinal pigment epithelium cells in adaptive optics–optical coherence tomography images with partial annotations and superhuman accuracy

Characterization of RNA editing and gene therapy with a compact CRISPR-Cas13 in the retina

CRISPR-Cas13 nucleases are programmable RNA-targeting effectors that can silence gene expression in a transient manner. Recent iterations of Cas13 nucleases are compact for adeno-associated virus (AAV) delivery to achieve strong and persistent expression of various organs in a safe manner. Here, we report significant transcriptomic signatures of Cas13bt3 expression in retinal cells and show all-in-one AAV gene therapy with Cas13bt3 can effectively silence VEGFA mRNA in human retinal organoids and humanized VEGF transgenic mouse (trVEGF029, Kimba) models. Specifically, human embryonic stem cells (hESC)-derived retinal pigment epithelium cells show high expression of Cas13bt3 from virus delivery corresponding to a significant reduction of VEGFA mRNA. We further show that intravitreal delivery of Cas13bt3 by AAV2.7m8 can efficiently transduce mouse retinal cells for specific knockdown of human VEGFA in the Kimba mouse. Our results reveal important considerations for assessing Cas13 activity, and establish the Cas13bt3 RNA editing system as a potential anti-VEGF agent that can achieve significant control of VEGFA for the treatment of retinal neovascularization.

Retinal G-protein-coupled receptor deletion exacerbates AMD-like changes via the PINK1-parkin pathway under oxidative stress.

The intake of high dietary fat has been correlated with the progression of age-related macular degeneration (AMD), affecting the function of the retinal pigment epithelium through oxidative stress. A high-fat diet (HFD) can lead to lipid metabolism disorders, excessive production of circulating free fatty acids, and systemic inflammation by aggravating the degree of oxidative stress. Deletion of the retinal G-protein-coupled receptor (RGR-d) has been identified in drusen. In this study, we investigated how the RGR-d exacerbates AMD-like changes under oxidative stress, both invivo and invitro. Fundus atrophy became evident, at 12 months old, particularly in the RGR-d + HFD group, and fluorescence angiography revealed narrower retinal vessels and a reduced perfusion area in the peripheral retina. Although rod electroretinography revealed decreasing trends in the a- and b-wave amplitudes in the RGR-d + HFD group at 12 months, the changes were not statistically significant. Mice in the RGR-d + HFD group showed a significantly thinner and more fragile retinal morphology than those in the WT + HFD group, with disordered and discontinuous pigment distribution in the RGR-d + HFD mice. Transmission electron microscopy revealed a thickened Bruch's membrane along the choriocapillaris endothelial cell wall in the RGR-d + HFD mice, and the outer nuclear layer structure appeared disorganized, with reduced nuclear density. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated significantly lower levels of 25(OH)-vitamin D3 metabolites in the RGR-d + HFD group. Under oxidative stress, RGR-d localized to the mitochondria and reduced the levels of the PINK1-parkin pathway. RGR-d mice fed an HFD were used as a new animal model of dry AMD. Under high-fat-induced oxidative stress, RGR-d accumulated in the mitochondria, disrupting normal mitophagy and causing cellular damage, thus exacerbating AMD-like changes both invivo and invitro.

SLC16A8 is a causal contributor to age-related macular degeneration risk

Age-related macular degeneration (AMD), a complex neurodegenerative disease, is a leading cause of visual impairment worldwide with a strong genetic component. Genetic studies have identified several loci, but few causal genes with functional characterization. Here we highlight multiple lines of evidence which show a causal role in AMD for SLC16A8, which encodes MCT3, a retinal pigment epithelium (RPE) specific lactate transporter. First, in an unbiased, genome-wide analysis of rare coding variants we show multiple SLC16A8 rare variants are associated with AMD risk, corroborating previous borderline significant reports from AMD rare variant studies. Second, we report a novel SLC16A8 mutation in a three-generation family with early onset macular degeneration. Finally, mis-expression in multiple model organisms shows functional and anatomic retinal consequences. This study highlights the important role for SLC16A8 and lactate regulation towards outer retina/RPE health and highlights a potential new therapeutic opportunity for the treatment of AMD.

Validation of Inter-Reader Agreement/Consistency for Quantification of Ellipsoid Zone Integrity and Sub-RPE Compartmental Features Across Retinal Diseases

Background: An unmet need exists when clinically assessing retinal and layer-based features of retinal diseases. Therefore, quantification of retinal-layer-thicknesses/fluid volumes using deep-learning-augmented platforms to reproduce human-obtained clinical measurements is needed. Methods: In this analysis, 210 spectral-domain optical coherence tomography (SD-OCT) scans (30 without pathology, 60 dry age-related macular degeneration [AMD], 60 wet AMD, and 60 diabetic macular edema [total 23,625 B-scans]) were included. A fully automated segmentation platform segmented four retinal layers for compartmental assessment (internal limiting membrane, ellipsoid zone [EZ], retinal pigment epithelium [RPE], and Bruch’s membrane). Two certified OCT readers independently completed manual segmentation and B-scan level validation of automated segmentation, with segmentation correction when needed (semi-automated). Certified reader metrics were compared to gold standard metrics using intraclass correlation coefficients (ICCs) to assess overall agreement. Across different diseases, several metrics generated from automated segmentations approached or matched human readers performance. Results: Absolute ICCs for retinal mean thickness measurements showed excellent agreement (range 0.980–0.999) across four cohorts. EZ-RPE thickness values and sub-RPE compartment ICCs demonstrated excellent agreement (ranges of 0.953–0.987 and 0.944–0.997, respectively) for full dataset, dry-AMD, and wet-AMD cohorts. Conclusions: Analyses demonstrated high reliability and consistency of segmentation of outer retinal compartmental features using a completely human/manual approach or a semi-automated approach to segmentation. These results support the critical role that measuring features, such as photoreceptor preservation through EZ integrity, in future clinical trials may optimize clinical care.

Micropulse Laser versus Eplerenone for Chronic Central Serous Chorioretinopathy: A 12-Month Comparison.

To compare the long-term efficacy of navigated subthreshold micropulse laser (NSML) and continuous oral eplerenone (EPL) in chronic central serous chorioretinopathy (cCSC). This retrospective observational study included 44 eyes with cCSC (EPL: n = 26; NSML: n = 18). Best-corrected visual acuity (BCVA), central macular thickness (CMT), subretinal fluid (SRF) height, and subfoveal choroidal thickness (SFCT) were evaluated over 12months. Both groups showed significant improvements in BCVA and CMT (p < 0.05). Complete SRF resolution was achieved in both groups by 12months, with NSML showing faster resolution (2.77 ± 1.43 vs. 6.34 ± 2.17months, p < 0.001). The EPL group demonstrated significant SFCT reduction at 6 and 12months (p = 0.001), while the NSML group showed no significant SFCT changes (p > 0.05). Both NSML and EPL improved retinal morphology and visual function in patients with cCSC. NSML achieved faster SRF resolution, while EPL resulted in more significant choroidal thickness reduction. These findings suggest distinct mechanisms of action: NSML primarily affects the retinal pigment epithelium, while EPL modulates choroidal vasculature. Treatment choice may depend on individual patient characteristics and treatment goals.

Dynamics of clinical and immunological parameters in retinal pigment epithelium transplantation in the context of combined immunosuppressive therapy in the rabbit model of retinal degeneration

Progressive damage of the retinal pigment epithelium (RPE) underlies the pathogenesis of degenerative retinal diseases such as: age-related macular degeneration (AMD), Stargardt’s disease, retinitis pigmentosa, Best’s disease and others. This group of diseases led by AMD leads to irreversible loss of visual functions, blindness and disability. The possibilities of therapy of late stages of AMD are extremely limited. The most promising approach to replace the damaged retinal pigment epithelium appears to be transplantation of RPE cells derived from induced pluripotent stem cells (iPSC-RPE) into the subretinal space (SRS). Despite immune privilege in the SRS, transplantation of xenogeneic cellular material causes severe inflammation in the posterior segment of the eye and leads to graft rejection in an in vivo experiment in the absence of immunosuppression. The solution to the problem of tissue incompatibility in this case can be the use of combined immunosuppressive therapy (CIT), aimed, on the one hand, at suppression of local inflammation (in the eye) and, on the other hand, at suppression of the systemic transplantation immune response. The aim of the study: clinical and immunological analysis of the results of transplantation of IPSC-RPE suspension on the background of CIT, including single intravitreal intraoperative administration of kenalog and further systemic application of mycophenolate mofetil (MMF), in the model of RPE atrophy in rabbits. Standard and specialized ophthalmological examination was performed at early and distant terms after the intervention in order to clinically assess the posttransplantation process. To analyze the immune status, vitreous humor (VH) and blood serum (BS) of rabbits of the experimental groups were collected. The concentrations of TGF-β1, TGF-β2, and IL-2 were determined in the biomaterial using solid-phase enzyme immunoassay. According to the results of the study, subretinal transplantation of IPSC-RPE, performed against the background of combination of single intravitreal intraoperative administration of kenalog and systemic application of MMF, is a safe method, which provides preservation of the retina and other adjacent structures of the eye and allows to prevent rejection of xenogenic material during its transplantation both in a healthy eye and with pre-formed RPE atrophy, which opens perspectives for full testing of biological effects realized by IPSC-RPE.

The ameliorating effects of adipose-derived stromal vascular fraction cells on blue light-induced rat retinal injury via modulation of TLR4 signaling, apoptosis, and glial cell activity.

Blue light (BL)-induced retinal injury has become a very common problem due to over exposure to blue light-emitting sources. This study aimed to investigate the possible ameliorating impact of stromal vascular fraction cells (SVFCs) on BL-induced retinal injury. Forty male albino rats were randomly allocated into four groups. The control group rats were kept in 12-h light/12-h dark. Rats of SVFC-control as the control group, but rats were intravenously injected once by SVFCs. Rats of both the BL-group and BL-SVFC group were exposed to BL for 2 weeks; then rats of the BL-SVFC group were intravenously injected once by SVFCs. Following the BL exposure, rats were kept for 8 weeks. Physical and physiological studies were performed; then retinal tissues were collected for biochemical and histological studies. The BL-group showed physical and physiological changes indicating affection of the visual function. Biochemical marker assessment showed a significant increase in MDA, TLR4 and MYD88 tissue levels with a significant decrease in TAC levels. Histological and ultrastructural assessment showed disruption of the normal histological architecture with retinal pigment epithelium, photoreceptors, and ganglion cell deterioration. A significant increase in NF-κB, caspase-3, and GFAP immunoreactivity was also detected. BL-SVFC group showed a significant improvement in physical, physiological, and biochemical parameters. Retinal tissues revealed amelioration of retinal structural and ultrastructural deterioration and a significant decrease in NF-κB and caspase-3 immunoreactivity with a significant increase in GFAP immunoreaction. This study concluded that SVFCs could ameliorate the BL-induced retinal injury through TLR-4/MYD-88/NF-κB signaling inhibition, regenerative, anti-oxidative, and anti-apoptotic effects.

Autosomal dominant macular dystrophy linked to a chromosome 17 tandem duplication.

Hereditary Macular Dystrophies (HMDs) are a genetically diverse group of disorders that cause central vision loss due to photoreceptor and retinal pigment epithelium (RPE) damage. We investigated a family with a presumed novel autosomal dominant HMD characterized by faint, hypopigmented RPE changes involving the central retina. Genome and RNA sequencing identified the disease-causing variant to be a 560 kilobase tandem duplication on chromosome 17 [NC_000017.10 (hg19): g.4012590_4573014dup], which led to the formation of a novel ZZEF1-ALOX15 fusion gene, that upregulates ALOX15. ALOX15 encodes a lipoxygenase involved in polyunsaturated fatty acid metabolism. Functional studies showed retinal disorganization, and photoreceptor and RPE damage following electroporation of the chimera transcript in mouse retina. Photoreceptor damage also occurred following electroporation with a native ALOX15 transcript but not with a near-null ALOX15 transcript. Affected patients' lymphoblasts demonstrated lower levels of ALOX15 substrates and an accumulation of neutral lipids. We implicated the fusion gene as the cause of this family's HMD, due to mis-localization and overexpression of ALOX15, driven by the ZZEF1 promoter. To our knowledge, this is the first reported instance of a fusion gene leading to HMD or inherited retinal dystrophy, highlighting the need to prioritize duplication analysis in unsolved retinal dystrophies.

Intravitreal Metformin Protects Against Choroidal Neovascularization and Light-Induced Retinal Degeneration

Neovascular age-related macular degeneration (nAMD), a leading cause of blindness in older adults, presents a challenging pathophysiology involving choroidal neovascularization (CNV) and retinal degeneration. Current treatments relying on intravitreal (IVT) administration of anti-angiogenic agents are costly and of moderate effectiveness. Metformin, the common anti-diabetic drug, has been associated with decreased odds of developing AMD. Studies have shown that metformin can mitigate cellular aging, neoangiogenesis, and inflammation across multiple diseases. This preclinical study assessed metformin’s impact on vessel growth using choroidal explants before exploring IVT metformin’s effects on laser-induced CNV and light-induced retinal degeneration in C57BL/6J and BALB/cJ mice, respectively. Metformin reduced new vessel growth in choroidal explants in a dose-dependent relationship. Following laser induction, IVT metformin suppressed CNV and decreased peripheral infiltration of IBA1+ macrophages/microglia. Furthermore, IVT metformin protected against retinal thinning in response to light-induced degeneration. IVT metformin downregulated genes in the choroid and retinal pigment epithelium which are associated with angiogenesis and inflammation, two key processes that drive nAMD progression. These findings underscore metformin’s capacity as an anti-angiogenic and neuroprotective agent, demonstrating this drug’s potential as an accessible option to help manage nAMD.

Lycium barbarum L. and Salvia miltiorrhiza Bunge extract ameliorates retinitis pigmentosa in rd10 mice by affecting endoplasmic reticulum stress

Ethnopharmacological relevanceLycium barbarum L. and Salvia miltiorrhiza Bunge (Gouqi and Danshen, LS) have led to their inclusion in the pharmacopoeia and healthcare systems of numerous countries globally. Traditional herbs known as LS are used in China to treat retinitis pigmentosa (RP). However, the mechanism is not clear. Aim of the studyThis study is to investigate the mechanism by which LS improves RP using rd10 mice as a model. Materials and methodsLS extract was used to treat the rd10 mice for four weeks. Fundus photographs, optical coherence tomography, electroretinography, histopathological examination, TUNEL apoptosis assay, digital PCR analysis, western blotting, and immunofluorescence double staining were performed. ResultsThe outer nuclear layer (ONL) thickness of the retina was significantly increased by the LS extract, improving atrophy, and both the ONL and the retinal pigment epithelium (RPE) layer were visible. Following treatment with LS extract, there was a notable increase in the magnitudes of ERG a- and b-waves in the retina, along with a significant reduction in the quantity of TUNEL-positive cells. Additionally, LS extract significantly reduced the levels of ER stress-related factors in rd10 mice. The results of immunofluorescence double staining further confirm that LS extract inhibits the GRP78/PERK/ATF4/CHOP pathway. ConclusionIn this study, the protective effects of LS extract on the retina were uncovered, suggesting that its mechanism could involve decreasing retinal cell apoptosis through the inhibition of the ER stress pathway.

Transplacental Transfer of Oxytocin and Its Impact on Neonatal Cord Blood and In Vitro Retinal Cell Activity.

The development of fetal organs can be impacted by systemic changes in maternal circulation, with the placenta playing a pivotal role in maintaining pregnancy homeostasis and nutrient exchange. In clinical obstetrics, oxytocin (OXT) is commonly used to induce labor. To explore the potential role of OXT in the placental homeostasis of OXT, we compared OXT levels in neonatal cord blood among neonates (23-42 weeks gestation) whose mothers either received prenatal OXT or experienced spontaneous labor. Our previous research revealed that the oxytocin receptor (OXTR), essential in forming the blood-retina barrier, is expressed in the retinal pigment epithelium (RPE). We hypothesized that perinatal OXT administration might influence the development of the neural retina and its vasculature, offering therapeutic potential for retinal diseases such as retinopathy of prematurity (ROP). Plasma OXT levels were measured using a commercial OXT ELISA kit. Human fetal RPE (hfRPE) cells treated with OXT (10 µM) were assessed for gene expression via RNA sequencing, revealing 14 downregulated and 32 upregulated genes. To validate these differentially expressed genes (DEGs), hfRPE cells were exposed to OXT (0.01, 0.1, 1, or 10 µM) for 12 h, followed by RNA analysis via real-time PCR. Functional, enrichment, and network analyses (Gene Ontology term, FunRich, Cytoscape) were performed to predict the affected pathways. This translational study suggests that OXT likely crosses the placenta, altering fetal OXT concentrations. RNA sequencing identified 46 DEGs involved in vital metabolic and signaling pathways and critical cellular components. Our results indicate that the perinatal administration of OXT may affect neural retina and retinal vessel development, making OXT a potential therapeutic option for developmental eye diseases, including ROP.

Punctate inner choroiditis and choroidal neovascular membrane formation following vitreoretinal surgery: A case report.

To report a case of punctate inner choroiditis (PIC) and subsequent choroidal neovascular membrane (CNVM) development in a young, high myope following vitreoretinal surgery for rhegmatogenous retinal detachment. A 44-year-old male with high myopia underwent pars plana vitrectomy for subtotal retinal detachment in the left eye, followed by cataract extraction and silicone oil removal. Three years postoperatively, he presented with blurred vision, and fundus examination revealed PIC lesions at the posterior pole. Spectral-domain optical coherence tomography (SD-OCT) showed characteristic features of PIC, including hyperreflective nodule-like elevations, disrupted ellipsoid and interdigitation zones, retinal pigment epithelium (RPE) elevations and increased choroidal hyper transmission signals. Initially, no treatment was initiated, and the patient was monitored. Three years later, the patient experienced further vision loss, and fundus examination showed progression of PIC lesions and new CNVM formation in the left eye. The patient was treated with systemic corticosteroids and an intravitreal anti-VEGF injection (Razumab® 0.5 mg/0.05 ml). Three weeks after the intervention, SD-OCT showed regression of the CNVM, and the patient's visual symptoms improved. This case underscores the importance of long-term follow-up and timely intervention in managing PIC, especially in high myopes post-retinal surgery. Early identification and treatment with systemic corticosteroids and anti-VEGF therapy are crucial to preserving visual function and preventing severe complications like CNVM.

Influence of vortex vein engorgement for photodynamic therapy in central serous chorioretinopathy

This study evaluates the efficacy of photodynamic therapy (PDT) in treating central serous chorioretinopathy (CSC) based on the number of engorged vortex vein draining macula visualized on ultra-widefield (UWF) indocyanine green angiography (ICGA). Thirty-six eyes of 36 patients with treatment-naïve CSC were included. Macula-draining vortex veins were assessed in each quadrant using UWF ICGA. The resolution of subretinal fluid (SRF), pigment epithelial detachment (PED), ellipsoid zone (EZ) disintegrity, and retinal pigment epithelium (RPE) irregularity were evaluated at 3 months after PDT. Visual and anatomical improvements were monitored for 12 months. Logistic regression analysis was performed to identify factors associated with poor visual outcomes. A higher number of macula-draining vortex vein was associated to persistent SRF (p = 0.004), PED (p = 0.001), EZ disintegrity (p = 0.011), and RPE irregularity (p = 0.001). Macula-draining vortex veins were also correlated with poor EZ restoration and limited best corrected visual acuity (BCVA) improvements. In multivariate analysis, the number of macula-draining vortex vein (B = 0.197, p = 0.047) was a risk factor for worse BCVA at 12 months. Increased macula-draining vortex vein was related with unfavorable anatomical and poor visual outcomes after PDT in CSC patients.

Genetic removal of Nlrp3 protects against sporadic and R345W Efemp1-induced basal laminar deposit formation.

Chronic, unresolved inflammation has long been speculated to serve as an initiating and propagating factor in numerous neurodegenerative diseases, including a leading cause of irreversible blindness in the elderly, age-related macular degeneration (AMD). Intracellular multiprotein complexes called inflammasomes in combination with activated caspases facilitate production of pro-inflammatory cytokines such as interleukin 1 beta. Specifically, the nucleotide-binding oligomerization (NOD)-like receptor protein 3 (NLRP3) has received heightened attention due to the wide range of stimuli to which it can respond and its potential involvement in AMD. In this study, we directly tested the role of Nlrp3 and its downstream effector, caspase 1 (Casp1) in mediating early AMD-like pathology (i.e., basal laminar deposits [BLamDs]) in wild-type (WT) mice and the Malattia Leventinese/Doyne honeycomb retinal dystrophy (ML/DHRD) mouse model (p.R345W mutation in Efemp1). Compared to aged-matched controls, R345W +/+ knockin mice demonstrated increased Muller cell gliosis, subretinal Iba-1 + microglial cells, higher Nlrp3 immunoreactivity in the retina, as well as significant transcriptional upregulation of complement component 3, Nlrp3, pro-Il1b, pro-caspase-1, and tissue inhibitor of matrix metalloproteinase 3 in the retinal pigmented epithelium (RPE)/choroid. These findings were accompanied by an age-related increase in BLamD formation in the R345W +/+ mice. Genetic elimination of either Nlrp3 or Casp1 significantly reduced both the size and coverage of BLamDs in the R345W +/+ background, highlighting an important and underappreciated pathway that could affect ML/DHRD onset and progression. Moreover, Nlrp3 knockout reduced spontaneous, idiopathic BLamDs in WT mice, suggesting translatability of our findings not only to rare inherited retinal dystrophies, but also potentially to AMD itself.

Ghost vessels in the eye: Cell free choriocapillaris domains in atrophic age-related macular degeneration

The choriocapillaris is a dense vascular bed in the inner choroid that supplies the photoreceptor cells and retinal pigment epithelium (RPE). While loss of choriocapillaris density has been described in association with age-related macular degeneration (AMD), whether these changes are primary or secondary to RPE degenerative changes in AMD has been debated. In this study we characterized choriocapillaris loss by quantifying “ghost” vessels in a series of 99 human donor maculae labeled with the UEA-I lectin, and found significant increases in early-intermediate AMD and a greater difference in geographic atrophy in areas with intact RPE. Eyes were genotyped at the CFH Tyr402His locus, and those homozygous for the His allele showed significantly more ghost vessels than those with other genotypes. When only non-AMD eyes were evaluated, His homozygotes had increased ghost vessel density but this trend did not reach statistical significance. These results support the notion that choriocapillaris death often precedes RPE degeneration in AMD and that this loss is an important therapeutic consideration for AMD.

New high-resolution prototype versus standard spectralis optical coherence tomography in patients with central serous chorioretinopathy

PurposeTo assess the accuracy of High-Resolution OCT in detecting biomarkers associated with central serous chorioretinopathy (CSC) compared to standard OCT.MethodsWe conducted a cross-sectional study involving CSC patients who underwent High-Resolution and standard OCT during the same visit. Using the SPECTRALIS High-Res OCT device (Heidelberg Engineering, Heidelberg, Germany), macular B-scans were obtained and compared with those acquired using a SPECTRALIS HRA + OCT device (Heidelberg Engineering, Heidelberg, Germany). Qualitative assessments were performed, and statistical analyses compared the performance of both OCT modalities.ResultsThirty-one patients diagnosed with CSC were included with a mean age of 56.3 years (± 10.2). Among them, 29% (n = 9) were classified as acute CSC (aCSC), while 71% (n = 22) had chronic CSC (cCSC). High-Resolution OCT outperformed standard OCT in detecting microstructural changes in the outer retinal layers, including a higher prevalence of disrupted interdigitation zone (IZ) (29% vs. 6%, p = 0.003) and retinal pigment epithelium (RPE) disruption (12% vs. 2%, p = 0.0024). Intergrader agreement was high (Cohen’s Kappa = 0.85).ConclusionHigh-Resolution OCT demonstrates promise in identifying critical biomarkers associated with CSC, particularly disruptions in the IZ and RPE. Further validation in larger cohorts is required to confirm their clinical relevance in patients with CSC.

Regualtion of LAMTOR1 by Oxidative Stress in Retinal Pigment Epithelium: Implications for Age-Related Macular Degeneration Pathogenesis

Oxidative stress is a critical pathogenic factor for age-related macular degeneration (AMD). Autophagy serves as a mechanism to counteract oxidative stress. LAMTOR1 regulates mTORC1 activity by recruiting or disassembling it on the lysosome under the addition or deprivation of amino acids. This regulation inhibits or enhances autophagy. Our study investigates whether oxidative stress impacts LAMTOR1, thereby adapting to oxidative conditions. We employed oxidative stressors, menadione (VK3) and 4-hydroxynonenal (4-HNE), and observed a reduction of LAMTOR1 in both human and mouse retinal pigment epithelium (RPE) following short-term (1h) and prolonged exposures (24h). Nrf2 overexpression increased both lamtor1 mRNA and LAMTOR1 protein in the RPE. To determine if Nrf2 regulates lamtor1 transcription, we cloned the deletion mutants of the lamtor1 promoter into a luciferase reporter. Although the promoter contained antioxidant response elements, transcriptional activity depended on the interaction between Nrf2 and the constructs containing the transcriptional start site. Moreover, Nrf2-driven transcription was significantly reduced by an inhibitor of histone acetyltransferase, p300. Correspondingly, Nrf2 overexpression increased levels of acetylated histone3 and p300. The reduction in LAMTOR1 by 4-HNE was reversed by pepstatin A and NH4Cl which block lysosomal degradation. 4-HNE increased TFEB nuclear translocation which was reversed by LAMTOR1 overexpression. In vivo, LAMTOR1 levels decreased in the photoreceptor and RPE layers of NaIO3-injected mice, compared to PBS-injected controls. In conclusion, oxidative injury reduces LAMTOR1, predominantly through lysosomal degradation although Nrf2-mediated histone acetylation enhances lamtor1 transcription. This study reveals a previously unrecognized regulatory mechanism of lamtor1 by oxidative stress, suggesting a novel role for LAMTOR1 in the pathogenesis of AMD.

Complete retinal pigment epithelium and outer retinal atrophy: Is it really an end-stage atrophy?

Geographic atrophy (GA), a late manifestation of age-related macular degeneration (AMD), leads to irreversible vision loss. Early identification of precursor lesions, such as incomplete and complete retinal pigment epithelium and outer retinal atrophy (iRORA and cRORA), is crucial for predicting GA formation. The latter stage has been associated with irreversible and progressive changes, and the eventual development of a dense scotoma on the compromised area. We present an 80-year-old woman with AMD in both eyes, demonstrating progressive changes over a 2-year follow-up. While the right eye developed cRORA with vision decline, the left eye exhibited unexpected restoration of the outer retinal layers within the cRORA lesion. This finding challenges the notion of "end-stage atrophy" in GA development and highlights the potential reversibility of early atrophic lesions. Recognizing these dynamics has implications for the development of targeted therapies aimed at preserving vision in AMD's early stages.