VISUALIZING RETINAL PIGMENT EPITHELIUM PHENOTYPES IN THE TRANSITION TO GEOGRAPHIC ATROPHY IN AGE-RELATED MACULAR DEGENERATION

The Total Macular Burden of Hyperreflective Foci and the Onset of Persistent Choroidal Hypertransmission Defects in Intermediate AMD

PURPOSE

The association between the total macular burden of hyperreflective foci (HRF) in eyes with intermediate AMD (iAMD) and the onset of persistent choroidal hypertransmission defects (hyperTDs) was studied using swept-source optical coherence tomography (SS-OCT).

DESIGN

Post hoc subgroup analysis of a prospective study.

METHODS

A retrospective review of iAMD eyes from subjects enrolled in a prospective SS-OCT study was performed. All eyes underwent 6×6 mm SS-OCT angiography (SS-OCTA) imaging at baseline and follow-up visits. En face sub-retinal pigment epithelium (subRPE) slabs with segmentation boundaries positioned 64-400 µm beneath Bruch's membrane (BM) were used to identify persistent choroidal hyperTDs. None of the eyes had persistent hyperTDs at baseline. The same subRPE slab was used to identify choroidal hypotransmission defects (hypoTDs) attributable to HRF located either intraretinally (iHRF) or along the RPE (rpeHRF) based on corresponding B-scans. A semiautomated algorithm was used by two independent graders to validate and refine the HRF outlines. The HRF area and the drusen volume within a 5mm fovea-centered circle were measured at each visit.

RESULTS

The median follow-up time for the 171 eyes from 121 patients included in this study was 59.1 months (95%CI: 52.0-67.8 months). Of these, 149 eyes (87%) had HRF, and 82 (48%) developed at least one persistent hyperTD during the follow-up. Although univariable Cox regression analyses showed that both drusen volume and total HRF area were associated with the onset of the first persistent hyperTD, multivariable analysis showed that the area of total HRF was the sole significant predictor for the onset of hyperTDs (P<0.001). ROC analysis identified an HRF area ≥ 0.07 mm² to predict the onset of persistent hyperTDs within one year with an area under the curve (AUC) of 0.661 (0.570-0.753), corresponding to a sensitivity of 55% and a specificity of 74% (P<0.001).

CONCLUSIONS

The total macular burden of HRF, which includes both the HRF along the RPE and within the retina, is an important predictor of disease progression from iAMD to the onset of persistent hyperTDs and should serve as a key OCT biomarker to select iAMD patients at high-risk for disease progression in future clinical trials.

Pegcetacoplan Treatment and Consensus Features of Geographic Atrophy Over 24 Months

Importance

Despite widespread availability and consensus on its advantages for detailed imaging of geographic atrophy (GA), spectral-domain optical coherence tomography (SD-OCT) might benefit from automated quantitative OCT analyses in GA diagnosis, monitoring, and reporting of its landmark clinical trials.

Objective

To analyze the association between pegcetacoplan and consensus GA SD-OCT end points.

Design, Setting, and Participants

This was a post hoc analysis of 11 614 SD-OCT volumes from 936 of the 1258 participants in 2 parallel phase 3 studies, the Study to Compare the Efficacy and Safety of Intravitreal APL-2 Therapy With Sham Injections in Patients With Geographic Atrophy (GA) Secondary to Age-Related Macular Degeneration (OAKS) and Study to Compare the Efficacy and Safety of Intravitreal APL-2 Therapy With Sham Injections in Patients With Geographic Atrophy (GA) Secondary to Age-Related Macular Degeneration (DERBY). OAKS and DERBY were 24-month, multicenter, randomized, double-masked, sham-controlled studies conducted from August 2018 to July 2020 among adults with GA with total area 2.5 to 17.5 mm2 on fundus autofluorescence imaging (if multifocal, at least 1 lesion ≥1.25 mm2). This analysis was conducted from September to December 2023.

Interventions

Study participants received pegcetacoplan, 15 mg per 0.1-mL intravitreal injection, monthly or every other month, or sham injection monthly or every other month.

Main Outcomes and Measures

The primary end point was the least squares mean change from baseline in area of retinal pigment epithelium and outer retinal atrophy in each of the 3 treatment arms (pegcetacoplan monthly, pegcetacoplan every other month, and pooled sham [sham monthly and sham every other month]) at 24 months. Feature-specific area analysis was conducted by Early Treatment Diabetic Retinopathy Study (ETDRS) regions of interest (ie, foveal, parafoveal, and perifoveal).

Results

Among 936 participants, the mean (SD) age was 78.5 (7.22) years, and 570 participants (60.9%) were female. Pegcetacoplan, but not sham treatment, was associated with reduced growth rates of SD-OCT biomarkers for GA for up to 24 months. Reductions vs sham in least squares mean (SE) change from baseline of retinal pigment epithelium and outer retinal atrophy area were detectable at every time point from 3 through 24 months (least squares mean difference vs pooled sham at month 24, pegcetacoplan monthly: -0.86 mm2; 95% CI, -1.15 to -0.57; P < .001; pegcetacoplan every other month: -0.69 mm2; 95% CI, -0.98 to -0.39; P < .001). This association was more pronounced with more frequent dosing (pegcetacoplan monthly vs pegcetacoplan every other month at month 24: -0.17 mm2; 95% CI, -0.43 to 0.08; P = .17). Stronger associations were observed in the parafoveal and perifoveal regions for both pegcetacoplan monthly and pegcetacoplan every other month.

Conclusions and Relevance

These findings offer additional insight into the potential effects of pegcetacoplan on the development of GA, including potential effects on the retinal pigment epithelium and photoreceptors.

Trial Registration

ClinicalTrials.gov Identifiers: NCT03525600 and NCT03525613.

Fundus autofluorescence of retinal atrophy progression between fundus flavimaculatus and extensive macular atrophy with pseudo-drusen

OBJECTIVE

To analyze the progression of macular atrophy in Fundus Flavimaculatus (FFM) versus Extensive Macular Atrophy with Pseudo-drusen (EMAP), using Spectralis® RegionFinder™ tool.

METHODS

Retrospective review of patients diagnosed with FFM and EMAP. Ophthalmic imaging features were reviewed by retina specialists for each patient in both eyes. The atrophic zones were measured on fundus autofluorescence acquisitions using the RegionFinder™ tool.

RESULTS

FFM group included 16 eyes of 8 patients, whose mean age was 61.42 ± 10.76 years, with a mean 4.54 ± 2.73 years of follow-up. EMAP group contained 16 eyes of 8 patients, whose mean age was 67.81 ± 3.03 years (p = 0.12), with a mean 3.62 ± 2.49 years of follow-up (P = 0.63). The atrophy progression rates were 3.73 ± 6.75 and 0.70 ± 0.98 mm2/year, for EMAP and FFM respectively. The yearly rate of progression of the atrophic areas in EMAP was 5.3 times higher than in FFM (mm2/year) (p = 0.03).

CONCLUSION

The progression of the atrophy in eyes with Extensive Macular Atrophy with Pseudo-drusen (EMAP) is significantly more rapid than in eyes with Fundus Flavimaculatus (FFM).

Isorhamnetin suppresses the epithelial-mesenchymal transition of the retinal pigment epithelium both in vivo and in vitro through Nrf2-dependent AKT/GSK-3β pathway

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly worldwide. Multiple studies have shown that epithelial-mesenchymal transition (EMT) plays a pivotal role in the pathogenesis of AMD. Isorhamnetin (Isor) is a flavonoid compound that inhibits EMT in tumor cells. However, whether it can also attenuate EMT in the retinal pigment epithelium (RPE) is unknown. Therefore, our study was designed to probe the possible impact of Isor on EMT process in both mouse retina and ARPE-19 cells. C57BL/6 mice were utilized to establish a dry AMD model. Isor and LCZ (a mixture of luteine/β-carotene/zinc gluconate) were administered orally for 3 months. The effects of Isor on the retina were evaluated using fundus autofluorescence, optical coherence tomography, and transmission electron microscopy. Transwell and wound healing assay were employed to assess ARPE-19 cell migration. Western blotting and immunofluorescence were used to measure the protein expressions associated with EMT, Nrf2 and AKT/GSK-3β pathway. The findings indicated that Isor alleviated dry AMD-like pathological changes in vehicle mice retina, inhibited the migration of Ox-LDL-treated ARPE-19 cells, and repressed the EMT processes in vivo and in vitro. Furthermore, Isor activated Nrf2 pathway and deactivated AKT/GSK-3β pathway in both vehicle mice and ARPE-19 cells. Interestingly, when Nrf2 siRNA was transfected into ARPE-19 cells, the inhibitory effect of Isor on EMT and AKT/GSK-3β pathway was attenuated. These results suggested that Isor inhibited EMT processes via Nrf2-dependent AKT/GSK-3β pathway and is a promising candidate for dry AMD treatment.

Histologic and Immunohistochemical Characterization of GA-Like Pathology in the Rat Subretinal Sodium Iodate Model

Purpose

Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration with multifactorial etiology and no well-established treatment. A model recapitulating the hallmarks would serve as a key to understanding the underlying pathologic mechanisms better. In this report, we further characterized our previously reported subretinal sodium iodate model of GA.

Methods

Retinal degeneration was induced in rats (6-8 weeks old) by subretinal injections of NaIO3 as described previously. Animals were sacrificed at 3, 8 and 12 weeks after injection and eyes were fixed or cryopreserved. Some choroids were processed as flatmounts while other eyes were cryopreserved, sectioned, and immunolabeled with a panel of antibodies. Finally, some eyes were prepared for transmission electron microscopic (TEM) analysis.

Results

NaIO3 subretinal injection resulted in a well-defined focal area of retinal pigment epithelium (RPE) degeneration surrounded by viable RPE. These atrophic lesions expanded over time. RPE morphologic changes at the border consisted of hypertrophy, multilayering, and the possible development of a migrating phenotype. Immunostaining of retinal sections demonstrated external limiting membrane descent, outer retinal tubulation (ORT), and extension of Müller cells toward RPE forming a glial membrane in the subretinal space of the atrophic area. TEM findings demonstrated RPE autophagy, cellular constituents of ORT, glial membranes, basal laminar deposits, and defects in Bruch's membrane.

Conclusions

In this study, we showed pathologic features of a rodent model resembling human GA in a temporal order through histology, immunofluorescence, and TEM analysis and gained insights into the cellular and subcellular levels of the GA-like phenotypes.

Translational Relevance

Despite its acute nature, the expansion of atrophy and the GA-like border in this rat model makes it ideal for studying disease progression and provides a treatment window to test potential therapeutics for GA.

Choroidal Hyper-Reflective Foci in Geographic Atrophy

Purpose

The purpose of this study was to describe the presence of choroidal hyper-reflective foci (HRF) on optical coherence tomography (OCT) in patients with geographic atrophy (GA). The relationship between the presence and quantity of choroidal HRF and other clinical and imaging factors was also investigated.

Methods

A total of 40 participants (40 eyes) with GA and age-related macular degeneration (AMD) were retrospectively analyzed. OCT images were reviewed for the presence, characteristics, and localization of choroidal HRF. The amount of choroidal HRF was quantified in different choroidal layers by two different (i.e. threshold reflectivity and manual counting) methodologies. The primary outcome was to describe and quantify choroidal HRF and correlate them with GA lesion size.

Results

Structural OCT images showed that all patients had multiple hyper-reflective deposits in different layers of the choroid. These hyper-reflective deposits in the choroid were located near Bruch's membrane or the edges of the blood vessels, particularly in the Sattler's layer, and none were observed inside the vessels. Choroidal HRF exhibited variable size and shape and varying effects on the posterior signal, including shadowing or hypertransmission. Mean ± SD number of choroidal HRF per B-scan was 21.5 ± 15.4 using the threshold reflectivity methodology and 25.1 ± 16.0 using the manual counting methodology. A significant correlation between the untransformed GA size and number of HRF was found, considering both quantitative strategies.

Conclusions

Hyper-reflective dots in the choroid of subjects with GA may be readily identified with structural OCT. These HRF might represent a natural component of the choroid that becomes more visible due to the absence of the retinal pigment epithelium.

Engineering a Biomimetic In Vitro Model of Bruch's Membrane Using Hagfish Slime Intermediate Filament Proteins

Bruch's membrane resides in the subretinal tissue and regulates the flow of nutrients and waste between the retinal pigment epithelial (RPE) and vascular layers of the eye. With age, Bruch's membrane becomes thicker, stiffer, and less permeable, which impedes its function as a boundary layer in the subretina. These changes contribute to pathologies such as age-related macular degeneration (AMD). To better understand how aging in Bruch's membrane affects surrounding tissues and to determine the relationship between aging and disease, an in vitro model of Bruch's membrane is needed. An accurate model of Bruch's membrane must be a proteinaceous, semipermeable, and nonporous biomaterial with similar mechanical properties to in vivo conditions. Additionally, this model must support RPE cell growth. While models of subretinal tissue exist, they typically differ from in vivo Bruch's membrane in one or more of these properties. This study evaluates the capability of membranes created from recombinant hagfish intermediate filament (rHIF) proteins to accurately replicate Bruch's membrane in an in vitro model of the subretinal tissue. The physical characteristics of these rHIF membranes were evaluated using mechanical testing, permeability assays, brightfield microscopy, and scanning electron microscopy. The capacity of the membranes to support RPE cell culture was determined using brightfield and fluorescent microscopy, as well as immunocytochemical staining. This study demonstrates that rHIF protein membranes are an appropriate biomaterial to accurately mimic both healthy and aged Bruch's membrane for in vitro modeling of the subretinal tissue.

Optical coherence tomography imaging biomarkers associated with neovascular age-related macular degeneration: a systematic review

The aim of this systematic literature review is twofold, (1) detail the impact of retinal biomarkers identifiable via optical coherence tomography (OCT) on disease progression and response to treatment in neovascular age-related macular degeneration (nAMD) and (2) establish which biomarkers are currently identifiable by artificial intelligence (AI) models and the utilisation of this technology. Following the PRISMA guidelines, PubMed was searched for peer-reviewed publications dated between January 2016 and January 2022.

POPULATION

Patients diagnosed with nAMD with OCT imaging.

SETTINGS

Comparable settings to NHS hospitals.

STUDY DESIGNS

Randomised controlled trials, prospective/retrospective cohort studies and review articles. From 228 articles, 130 were full-text reviewed, 50 were removed for falling outside the scope of this review with 10 added from the author's inventory, resulting in the inclusion of 90 articles. From 9 biomarkers identified; intraretinal fluid (IRF), subretinal fluid, pigment epithelial detachment, subretinal hyperreflective material (SHRM), retinal pigmental epithelial (RPE) atrophy, drusen, outer retinal tabulation (ORT), hyperreflective foci (HF) and retinal thickness, 5 are considered pertinent to nAMD disease progression; IRF, SHRM, drusen, ORT and HF. A number of these biomarkers can be classified using current AI models. Significant retinal biomarkers pertinent to disease activity and progression in nAMD are identifiable via OCT; IRF being the most important in terms of the significant impact on visual outcome. Incorporating AI into ophthalmology practice is a promising advancement towards automated and reproducible analyses of OCT data with the ability to diagnose disease and predict future disease conversion.

SYSTEMATIC REVIEW REGISTRATION

This review has been registered with PROSPERO (registration ID: CRD42021233200).

Ex Vivo OCT-Based Multimodal Imaging of Human Donor Eyes for Research into Age-Related Macular Degeneration

A progression sequence for age-related macular degeneration (AMD) learned from optical coherence tomography (OCT)-based multimodal (MMI) clinical imaging could add prognostic value to laboratory findings. In this work, ex vivo OCT and MMI were applied to human donor eyes prior to retinal tissue sectioning. The eyes were recovered from non-diabetic white donors aged ≥80 years old, with a death-to-preservation time (DtoP) of ≤6 h. The globes were recovered on-site, scored with an 18 mm trephine to facilitate cornea removal, and immersed in buffered 4% paraformaldehyde. Color fundus images were acquired after anterior segment removal with a dissecting scope and an SLR camera using trans-, epi-, and flash illumination at three magnifications. The globes were placed in a buffer within a custom-designed chamber with a 60 diopter lens. They were imaged with spectral domain OCT (30° macula cube, 30 µm spacing, averaging = 25), near-infrared reflectance, 488 nm autofluorescence, and 787 nm autofluorescence. The AMD eyes showed a change in the retinal pigment epithelium (RPE), with drusen or subretinal drusenoid deposits (SDDs), with or without neovascularization, and without evidence of other causes. Between June 2016 and September 2017, 94 right eyes and 90 left eyes were recovered (DtoP: 3.9 ± 1.0 h). Of the 184 eyes, 40.2% had AMD, including early intermediate (22.8%), atrophic (7.6%), and neovascular (9.8%) AMD, and 39.7% had unremarkable maculas. Drusen, SDDs, hyper-reflective foci, atrophy, and fibrovascular scars were identified using OCT. Artifacts included tissue opacification, detachments (bacillary, retinal, RPE, choroidal), foveal cystic change, an undulating RPE, and mechanical damage. To guide the cryo-sectioning, OCT volumes were used to find the fovea and optic nerve head landmarks and specific pathologies. The ex vivo volumes were registered with the in vivo volumes by selecting the reference function for eye tracking. The ex vivo visibility of the pathology seen in vivo depends on the preservation quality. Within 16 months, 75 rapid DtoP donor eyes at all stages of AMD were recovered and staged using clinical MMI methods.

A Protocol to Evaluate and Quantify Retinal Pigmented Epithelium Pathologies in Mouse Models of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a debilitating retinal disorder in aging populations. It is widely believed that dysfunction of the retinal pigmented epithelium (RPE) is a key pathobiological event in AMD. To understand the mechanisms that lead to RPE dysfunction, mouse models can be utilized by researchers. It has been established by previous studies that mice can develop RPE pathologies, some of which are observed in the eyes of individuals diagnosed with AMD. Here, we describe a phenotyping protocol to assess RPE pathologies in mice. This protocol includes the preparation and evaluation of retinal cross-sections using light microscopy and transmission electron microscopy, as well as that of RPE flat mounts by confocal microscopy. We detail the common types of murine RPE pathologies observed by these techniques and ways to quantify them through unbiased methods for statistical testing. As proof of concept, we use this RPE phenotyping protocol to quantify the RPE pathologies observed in mice overexpressing transmembrane protein 135 (Tmem135) and aged wild-type C57BL/6J mice. The main goal of this protocol is to present standard RPE phenotyping methods with unbiased quantitative assessments for scientists using mouse models of AMD.

Mitophagy initiates retrograde mitochondrial-nuclear signaling to guide retinal pigment cell heterogeneity

Age-related macular degeneration (AMD), the leading cause of blindness among the elderly, is without treatment for early disease. Degenerative retinal pigment epithelial (RPE) cell heterogeneity is a well-recognized but understudied pathogenic factor. Due to the daily phagocytosis of photoreceptor outer segments, unique photo-oxidative stress, and high metabolism for maintaining vision, the RPE has robust macroautophagy/autophagy, and mitochondrial and antioxidant networks. However, the autophagy subtype, mitophagy, in the RPE and AMD is understudied. Here, we found decreased PINK1 (PTEN induced kinase 1) in perifoveal RPE of early AMD eyes. PINK1-deficient RPE have impaired mitophagy and mitochondrial function that triggers death-resistant epithelial-mesenchymal transition (EMT). This reprogramming is mediated by novel retrograde mitochondrial-nuclear signaling (RMNS) through superoxide, NFE2L2 (NFE2 like bZIP transcription factor 2), TXNRD1 (thioredoxin reductase 1), and phosphoinositide 3-kinase (PI3K)-AKT (AKT serine/threonine kinase) that induced canonical transcription factors ZEB1 (zinc finger E-box binding homeobox 1) and SNAI1 (Snail family transcriptional repressor 1) and an EMT transcriptome. NFE2L2 deficiency disrupted RMNS that paradoxically normalized morphology but decreased function and viability. Thus, RPE heterogeneity is defined by the interaction of two cytoprotective pathways that is triggered by mitophagy function. By neutralizing the consequences of impaired mitophagy, an antioxidant dendrimer tropic for the RPE and mitochondria, EMT (a recognized AMD alteration) was abrogated to offer potential therapy for early AMD, a stage without treatment.Abbreviations: ACTB: actin beta; AKT: AKT serine/threonine kinase; AMD: age-related macular degeneration; CCCP: cyanide m-chlorophenyl hydrazone; CDH1: cadherin 1; DAVID: Database for Annotation, Visualization and Integrated Discovery; DHE: dihydroethidium; D-NAC: N-acetyl-l-cysteine conjugated to a poly(amido amine) dendrimer; ECAR: extracellular acidification rate; EMT: epithelial-mesenchymal transition; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GSEA: Gene Set Enrichment Analysis; HSPD1: heat shock protein family D (Hsp60) member 1; IVT: intravitreal; KD: knockdown; LMNA, lamin A/C; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; MMP: mitochondrial membrane potential; NAC: N-acetyl-l-cysteine; NQO1: NAD(P)H quinone dehydrogenase 1; NFE2L2: NFE2 like bZIP transcription factor 2; O2-: superoxide anion; OCR: oxygen consumption rate; PI3K: phosphoinositide 3-kinase; PINK1: PTEN induced kinase 1; RMNS: retrograde mitochondrial-nuclear signaling; ROS: reactive oxygen species; RPE: retinal pigment epithelium; SNAI1: snail family transcriptional repressor 1; TJP1: tight junction protein 1; TPP-D-NAC: triphenyl phosphinium and N-acetyl-l-cysteine conjugated to a poly(amido amine) dendrimer; TIMM23: translocase of inner mitochondrial membrane 23; TOMM20: translocase of outer mitochondrial membrane 20; Trig: trigonelline; TXNRD1: thioredoxin reductase 1; VIM: vimentin; WT: wild-type; ZEB1: zinc finger E-box binding homeobox 1.

Modeling inducible neuropathologies of the retina with differential phenotypes in organoids

Neurodegenerative diseases remain incompletely understood and therapies are needed. Stem cell-derived organoid models facilitate fundamental and translational medicine research. However, to which extent differential neuronal and glial pathologic processes can be reproduced in current systems is still unclear. Here, we tested 16 different chemical, physical, and cell functional manipulations in mouse retina organoids to further explore this. Some of the treatments induce differential phenotypes, indicating that organoids are competent to reproduce distinct pathologic processes. Notably, mouse retina organoids even reproduce a complex pathology phenotype with combined photoreceptor neurodegeneration and glial pathologies upon combined (not single) application of HBEGF and TNF, two factors previously associated with neurodegenerative diseases. Pharmacological inhibitors for MAPK signaling completely prevent photoreceptor and glial pathologies, while inhibitors for Rho/ROCK, NFkB, and CDK4 differentially affect them. In conclusion, mouse retina organoids facilitate reproduction of distinct and complex pathologies, mechanistic access, insights for further organoid optimization, and modeling of differential phenotypes for future applications in fundamental and translational medicine research.

Prolonged Lifetimes of Histologic Autofluorescence in Ectopic Retinal Pigment Epithelium in Age-Related Macular Degeneration

Purpose

The purpose of this study was to investigate histologic autofluorescence lifetimes and spectra of retinal pigment epithelium (RPE) on the transition from normal aging to RPE activation and migration in age-related macular degeneration (AMD).

Methods

Autofluorescence lifetimes and spectra of 9 donor eyes were analyzed in cryosections by means of 2-photon excited fluorescence at 960 nm. Spectra were detected at 483 to 665 nm. Lifetimes were measured using time-correlated single photon counting in 2 spectral channels: 500 to 550 nm (short-wavelength spectral channel [SSC]) and 550 to 700 nm (long-wavelength spectral channel [LSC]). Fluorescence decays over time were approximated by a series of three exponential functions. The amplitude-weighted mean fluorescence lifetime was determined. Markers for retinoid activity (RPE65) and immune function (CD68) were immunolocalized in selected neighboring sections.

Results

We identified 9 RPE morphology phenotypes resulting in 399 regions of interest (ROIs) for spectral and 497 ROIs for lifetime measurements. RPE dysmorphia results in a shorter wavelength peak of spectral emission: normal aging versus RPE migrated into the retina (intraELM) = 601.7 (9.5) nm versus 581.6 (7.3) nm, P < 0.001, whereas autofluorescence lifetimes increase: normal aging versus intraELM: SSC 180 (44) picosecond (ps) versus 320 (86) ps, P < 0.001; and LSC 250 (55) ps versus 441 (76) ps, P < 0.001. Ectopic RPE within the neurosensory retina is strongly CD68 positive and RPE65 negative.

Conclusions

In the process of RPE degeneration, comprising different steps of dysmorphia and migration, lengthening of autofluorescence lifetimes and a hypsochromic shift of emission spectra can be observed. These autofluorescence changes might provide early biomarkers for AMD progression and contribute to our understanding of RPE-driven pathology.

Does the Outer Retinal Thickness Around Geographic Atrophy Represent Another Clinical Biomarker for Predicting Growth?

PURPOSE

To determine whether the outer retinal layer (ORL) thickness around geographic atrophy (GA) could serve as a clinical biomarker to predict the annual enlargement rate (ER) of GA.

DESIGN

Retrospective analysis of a prospective, observational case series.

METHODS

Eyes with GA were imaged with a swept-source OCT 6 × 6 mm scan pattern. GA lesions were measured from customized en face OCT images and the annual ERs were calculated. The ORL was defined and segmented from the inner boundary of outer plexiform layer (OPL) to the inner boundary of retinal pigment epithelium (RPE) layer. The ORL thickness was measured at different subregions around GA.

RESULTS

A total of 38 eyes from 27 participants were included. The same eyes were used for the choriocapillaris (CC) flow deficit (FD) analysis and the RPE to the Bruch membrane (RPE-BM) distance measurements. A negative correlation was observed between the ORL thickness and the GA growth. The ORL thickness in a 300-μm rim around GA showed the strongest correlation with the GA growth (r = -0.457, P = .004). No correlations were found between the ORL thickness and the CC FDs; however, a significant correlation was found between the ORL thickness and the RPE-BM distances around GA (r = -0.398, P = .013).

CONCLUSIONS

ORL thickness showed a significant negative correlation with annual GA growth, but also showed a significant correlation with the RPE-BM distances, suggesting that they were dependently correlated with GA growth. This finding suggests that the loss of photoreceptors was associated with the formation of basal laminar deposits around GA.

FoxP3 expression by retinal pigment epithelial cells: transcription factor with potential relevance for the pathology of age-related macular degeneration

Background

Forkhead-Box-Protein P3 (FoxP3) is a transcription factor and marker of regulatory T cells, converting naive T cells into Tregs that can downregulate the effector function of other T cells. We previously detected the expression of FoxP3 in retinal pigment epithelial (RPE) cells, forming the outer blood–retina barrier of the immune privileged eye.

Methods

We investigated the expression, subcellular localization, and phosphorylation of FoxP3 in RPE cells in vivo and in vitro after treatment with various stressors including age, retinal laser burn, autoimmune inflammation, exposure to cigarette smoke, in addition of IL-1β and mechanical cell monolayer destruction. Eye tissue from humans, mouse models of retinal degeneration and rats, and ARPE-19, a human RPE cell line for in vitro experiments, underwent immunohistochemical, immunofluorescence staining, and PCR or immunoblot analysis to determine the intracellular localization and phosphorylation of FoxP3. Cytokine expression of stressed cultured RPE cells was investigated by multiplex bead analysis. Depletion of the FoxP3 gene was performed with CRISPR/Cas9 editing.

Results

RPE in vivo displayed increased nuclear FoxP3-expression with increases in age and inflammation, long-term exposure of mice to cigarette smoke, or after laser burn injury. The human RPE cell line ARPE-19 constitutively expressed nuclear FoxP3 under non-confluent culture conditions, representing a regulatory phenotype under chronic stress. Confluently grown cells expressed cytosolic FoxP3 that was translocated to the nucleus after treatment with IL-1β to imitate activated macrophages or after mechanical destruction of the monolayer. Moreover, with depletion of FoxP3, but not of a control gene, by CRISPR/Cas9 gene editing decreased stress resistance of RPE cells.

Conclusion

Our data suggest that FoxP3 is upregulated by age and under cellular stress and might be important for RPE function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02620-w.

HBEGF-TNF induce a complex outer retinal pathology with photoreceptor cell extrusion in human organoids

Human organoids could facilitate research of complex and currently incurable neuropathologies, such as age-related macular degeneration (AMD) which causes blindness. Here, we establish a human retinal organoid system reproducing several parameters of the human retina, including some within the macula, to model a complex combination of photoreceptor and glial pathologies. We show that combined application of TNF and HBEGF, factors associated with neuropathologies, is sufficient to induce photoreceptor degeneration, glial pathologies, dyslamination, and scar formation: These develop simultaneously and progressively as one complex phenotype. Histologic, transcriptome, live-imaging, and mechanistic studies reveal a previously unknown pathomechanism: Photoreceptor neurodegeneration via cell extrusion. This could be relevant for aging, AMD, and some inherited diseases. Pharmacological inhibitors of the mechanosensor PIEZO1, MAPK, and actomyosin each avert pathogenesis; a PIEZO1 activator induces photoreceptor extrusion. Our model offers mechanistic insights, hypotheses for neuropathologies, and it could be used to develop therapies to prevent vision loss or to regenerate the retina in patients suffering from AMD and other diseases.

Sub-retinal pigment epithelium tubules in non-neovascular age-related macular degeneration

To describe a novel optical coherence tomography (OCT) signature resembling sub-retinal pigment epithelium (RPE) tubules (SRT) in non-neovascular age-related macular degeneration (AMD). Patients suffering from non-neovascular AMD with complete medical records and multimodal imaging were retrospectively revised in three different tertiary care centers. Multimodal imaging included color fundus photograph, spectral-domain OCT (Spectralis, Heidelberg Engineering, Germany), fundus autofluorescence, OCT angiography (RTVue XR Avanti, Optovue, Inc., Fremont, CA). A total of 7 eyes of 7 patients with drusenoid pigment epithelium detachment (PED) were consecutively analyzed. The sub-RPE tubules appeared as ovoidal structures with a hyperreflective contour and hyporeflective interior appreciable in the sub-RPE-basal lamina (BL) space on OCT B-scan. The anatomical location of the sub-RPE formations was lying above the Bruch’s membrane in 5/7 cases (71.4%) or floating in the sub-RPE-BL space in 2/7 cases (28.6%). En-face OCTA revealed a curvilinear tubulation-like structure corresponding to SRT without flow signal. Sub-RPE tubules represent a newly identified OCT signature observed in eyes with drusenoid PED. The presumed origin may include a variant of calcified structure or alternatively activated RPE cells with some residual BL or basal laminar deposits attracted to BrM for craving oxygen.

Chorioretinal thickness and retinal pigment epithelial degeneration of fellow eyes in patients with unilateral neovascular age-related macular degeneration with subretinal drusenoid deposits

Background

We sought to investigate the chorioretinal thickness and retinal pigment epithelial (RPE) degenerative features of eyes with early age-related macular degeneration (AMD) and subretinal drusenoid deposits (SDDs) according to the presence of macular neovascularization (MNV) in the fellow eyes.

Methods

We classified 70 eyes into two groups of 47 eyes with non-neovascular AMD and 23 eyes with neovascular AMD, respectively, according to the presence of MNV in the fellow eyes. The mean macular retinal, ganglion cell–inner plexiform layer (GCIPL), and choroidal thickness values and RPE features of the 6-mm-diameter zone were compared. RPE degeneration was defined as a lesion with an incomplete RPE and outer retinal atrophy (iRORA) or attenuated RPE reflectivity with diffuse basal laminar deposits, which was defined as when the eye showed an attenuated RPE line with granular features and mixed reflectivity in combination with sub-RPE deposits with a lesion ≥ 1,000 µm in length.

Results

Mean retinal, GCIPL, and choroidal thickness values (286.69 ± 15.02 µm, 64.36 ± 4.21 µm, and 156.11 ± 33.10 µm) of the neovascular AMD group were greater than those (278.61 ± 13.96 µm, 61.44 ± 4.63 µm, and 133.59 ± 34.33 µm) of the non-neovascular AMD group (all P < 0.05). RPE degeneration was more prevalent in the neovascular AMD group (65.2%) than the non-neovascular AMD group (38.3%; P = 0.034). Greater mean GCIPL and choroidal thickness values and the presence of RPE degeneration were associated with type 3 MNV in fellow eyes (all P < 0.05).

Conclusions

Different degenerative features according to MNV in fellow eyes of patients with AMD and SDDs suggest that variable degenerative features might be present during disease progression and have an association with the phenotype.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02518-4.

Long Term Time-Lapse Imaging of Geographic Atrophy: A Pilot Study

Geographic atrophy (GA), the late stage of age-related macular degeneration, is a major cause of visual disability whose pathophysiology remains largely unknown. Modern fundus imaging and histology revealed the complexity of the cellular changes that accompanies atrophy. Documenting the activity of the disease in the margins of atrophy, where the transition from health to disease occurs, would contribute to a better understanding of the progression of GA. Time-lapse imaging facilitates the identification of structural continuities in changing environments. In this retrospective pilot study, we documented the long-term changes in atrophy margins by time-lapse imaging of infrared scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) images in 6 cases of GA covering a mean period of 32.8 months (range, 18–72). The mean interval between imaging sessions was 2.4 months (range, 1.4–3.8). By viewing time-lapse sequences we observed extensive changes in the pattern of marginal hyperreflective spots, which associated fragmentation, increase and/or disappearance. Over the entire span of the follow-up, the most striking changes were those affecting hyperreflective spots closest to margins of atrophy, on the non-atrophic side of the retina; a continuum between the successive positions of some of the hyperreflective spots was detected, both by SLO and OCT. This continuum in their successive positions resulted in a subjective impression of a centrifugal motion of hyperreflective spots ahead of atrophy progression. Such mobilization of hyperreflective spots was detected up to several hundred microns away from atrophic borders. Such process is likely to reflect the inflammatory and degenerative process underlying GA progression and hence deserves further investigations. These results highlight the interest of multimodal time-lapse imaging to document cell-scale dynamics during progression of GA.

Association of Pegcetacoplan With Progression of Incomplete Retinal Pigment Epithelium and Outer Retinal Atrophy in Age-Related Macular Degeneration: A Post Hoc Analysis of the FILLY Randomized Clinical Trial

IMPORTANCE

Change in areas of incomplete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA) within eyes with geographic atrophy (GA) might reflect similar changes among eyes with drusen but no GA.

OBJECTIVE

To evaluate the potential association of pegcetacoplan with progression of iRORA in eyes with GA secondary to AMD.

DESIGN, SETTING, AND PARTICIPANTS

This post hoc analysis of the phase 2 multicenter, randomized, single-masked, sham-controlled FILLY trial of intravitreal pegcetacoplan for 12 months took place from February 2 to July 7, 2020. Participants comprised 167 patients with GA secondary to AMD who received pegcetacoplan monthly (n = 41) or every other month (n = 56) or a sham injection (n = 70) in the FILLY trial, completed the month 12 study visit, and did not develop exudative AMD.

INTERVENTIONS

Intravitreal pegcetacoplan, 15 mg, or sham injection, monthly or every other month for 12 months.

MAIN OUTCOMES AND MEASURES

Masked readers analyzed spectral-domain optical coherence tomography scans in regions beyond a perimeter of 500 μm from the GA border according to the Classification of Atrophy Meetings criteria. Primary outcome measures were progression from iRORA to complete RPE and outer retina atrophy (cRORA) from baseline to 6 and 12 months.

RESULTS

Among the 167 patients in the study, at baseline, iRORA was present in 45.0% of study eyes (18 of 40) in the pegcetacoplan monthly group, 61.8% of study eyes (34 of 55) in the pegcetacoplan every other month group, and 50.7% of study eyes (34 of 67) in the sham group. At 12 months, progression from iRORA to cRORA occurred in 50.0% of study eyes (9 of 18) in the pegcetacoplan monthly group (P = .02 vs sham), 60.6% of study eyes (20 of 33) in the pegcetacoplan every other month group (P = .06 vs sham), and 81.8% of study eyes (27 of 33) in the sham group. Compared with sham treatment, the relative risk of progression at 12 months from iRORA to cRORA was 0.61 (95% CI, 0.37-1.00) for eyes in the pegcetacoplan monthly group and 0.74 (95% CI, 0.54-1.02) for eyes in the pegcetacoplan every other month group.

CONCLUSIONS AND RELEVANCE

Eyes receiving intravitreal pegcetacoplan had lower rates of progression from iRORA to cRORA compared with controls, suggesting a potential role for pegcetacoplan therapy earlier in the progression of AMD prior to the development of GA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02503332.

Dark Adaptation and Its Role in Age-Related Macular Degeneration

Dark adaptation (DA) refers to the slow recovery of visual sensitivity in darkness following exposure to intense or prolonged illumination, which bleaches a significant amount of the rhodopsin. This natural process also offers an opportunity to understand cellular function in the outer retina and evaluate for presence of disease. How our eyes adapt to darkness can be a key indicator of retinal health, which can be altered in the presence of certain diseases, such as age-related macular degeneration (AMD). A specific focus on clinical aspects of DA measurement and its significance to furthering our understanding of AMD has revealed essential findings underlying the pathobiology of the disease. The process of dark adaptation involves phototransduction taking place mainly between the photoreceptor outer segments and the retinal pigment epithelial (RPE) layer. DA occurs over a large range of luminance and is modulated by both cone and rod photoreceptors. In the photopic ranges, rods are saturated and cone cells adapt to the high luminance levels. However, under scotopic ranges, cones are unable to respond to the dim luminance and rods modulate the responses to lower levels of light as they can respond to even a single photon. Since the cone visual cycle is also based on the Muller cells, measuring the impairment in rod-based dark adaptation is thought to be particularly relevant to diseases such as AMD, which involves both photoreceptors and RPE. Dark adaptation parameters are metrics derived from curve-fitting dark adaptation sensitivities over time and can represent specific cellular function. Parameters such as the cone-rod break (CRB) and rod intercept time (RIT) are particularly sensitive to changes in the outer retina. There is some structural and functional continuum between normal aging and the AMD pathology. Many studies have shown an increase of the rod intercept time (RIT), i.e., delays in rod-mediated DA in AMD patients with increasing disease severity determined by increased drusen grade, pigment changes and the presence of subretinal drusenoid deposits (SDD) and association with certain morphological features in the peripheral retina. Specifications of spatial testing location, repeatability of the testing, ease and availability of the testing device in clinical settings, and test duration in elderly population are also important. We provide a detailed overview in light of all these factors.

Lipid Droplet Accumulation Promotes RPE Dysfunction

Non-exudative age-related macular degeneration (AMD) is an irreversibly progressive retinal degenerative disease characterized by dysfunction and loss of retinal pigment epithelium (RPE). It has been suggested that impaired phagocytosis of the RPE is involved in the progression of non-exudative AMD, but the mechanism is not fully clear. In this study, we investigated the effect of lipid droplet accumulation on RPE function. Compared to young mice, the expression of lipid droplet-associated proteins increased in the RPE-choroidal complex, and lipid droplet in the RPE was observed in aged pigmented mice (12-month-old). Repeated treatment of the photoreceptor outer segment against ARPE-19 resulted in lipid droplets in ARPE-19 cells in vitro. Oleic acid treatment for ARPE-19 cells to form intracellular lipid droplet reduced the POS uptake into the ARPE-19 cells without causing a decrease in cell viability. The suppression of the POS uptake by lipid droplet formation improved by inhibiting lipid droplet formation using triacsin C. Moreover, the amount of intracellular reactive oxygen species was suppressed by the triacsin C treatment. These results indicate that lipid droplet is involved in the RPE dysfunction, and inhibiting lipid droplet formation may be a target for preventing and treating non-exudative AMD.

Spatial Dissociation of Subretinal Drusenoid Deposits and Impaired Scotopic and Mesopic Sensitivity in AMD

Purpose

Subretinal drusenoid deposits (SDD) first appear in the rod-rich perifovea and can extend to the cone-rich fovea. To refine the spatial relationship of visual dysfunction with SDD burden, we determined the topography of mesopic and scotopic light sensitivity in participants with non-neovascular AMD with and without SDD.

Methods

Thirty-three subjects were classified into three groups: normal (n = 9), AMD-Drusen (with drusen and without SDD; n = 12), and AMD-SDD (predominantly SDD; n = 12). Mesopic and scotopic microperimetry were performed using 68 targets within the Early Treatment Diabetic Retinopathy Study grid, including points at 1.7° from the foveal center (rod:cone ratio, 0.35). Age-adjusted linear regression was used to compare mesopic and scotopic light sensitivities across groups.

Results

Across the entire Early Treatment Diabetic Retinopathy Study grid and within individual subfields, the three groups differed significantly for mesopic and scotopic light sensitivities (all P < 0.05). The AMD-SDD group exhibited significantly decreased mesopic and scotopic sensitivity versus both the normal and the AMD-Drusen groups (all P < 0.05), while AMD-Drusen and normal eyes did not significantly differ (all P > 0.05). The lowest relative sensitivities were recorded for scotopic light levels, especially in the central subfield, in the AMD-SDD group.

Conclusions

SDD-associated decrements in rod-mediated vision can be detected close to the foveola, and these deficits are proportionately worse than functional loss in the rod-rich perifovea. This finding suggests that factors other than the previously hypothesized direct cytotoxicity to photoreceptors and local transport barrier limitations may negatively impact vision. Larger prospective studies are required to confirm these observations.

Risk Classification for Progression to Subfoveal Geographic Atrophy in Dry Age-Related Macular Degeneration Using Machine Learning-Enabled Outer Retinal Feature Extraction

BACKGROUND AND OBJECTIVE

To evaluate the utility of spectral-domain optical coherence tomography biomarkers to predict the development of subfoveal geographic atrophy (sfGA).

PATIENTS AND METHODS

This was a retrospective cohort analysis including 137 individuals with dry age-related macular degeneration without sfGA with 5 years of follow-up. Multiple spectral-domain optical coherence tomography quantitative metrics were generated, including ellipsoid zone (EZ) integrity and subretinal pigment epithelium (sub-RPE) compartment features.

RESULTS

Reduced mean EZ-RPE central subfield thickness and increased sub-RPE compartment thickness were significantly different between sfGA convertors and nonconvertors at baseline in both 2-year and 5-year sfGA risk assessment. Longitudinal change assessment showed a significantly higher degradation of EZ integrity in sfGA convertors. The predictive performance of a machine learning classification model based on 5-year and 2-year risk conversion to sfGA demonstrated an area under the receiver operating characteristic curve of 0.92 ± 0.06 and 0.96 ± 0.04, respectively.

CONCLUSIONS

Quantitative outer retinal and sub-RPE feature assessment using a machine learning-enabled retinal segmentation platform provides multiple parameters that are associated with progression to sfGA. [Ophthalmic Surg Lasers Imaging. 2022;53:31-39.].

Hyperreflective Foci, Optical Coherence Tomography Progression Indicators in Age-Related Macular Degeneration, Include Transdifferentiated Retinal Pigment Epithelium

Purpose

By optical coherence tomography (OCT) imaging, hyperreflective foci (HRF) indicate progression risk for advanced age-related macular degeneration (AMD) and are in part attributable to ectopic retinal pigment epithelium (RPE). We hypothesized that ectopic RPE are molecularly distinct from in-layer cells and that their cross-retinal course follows Müller glia.

Methods

In clinical OCT (61 eyes, 44 patients with AMD, 79.4 ± 7.7 years; 29 female; follow-up = 4.7 ± 0.9 years), one HRF type, RPE plume (n = 129 in 4 morphologies), was reviewed. Twenty eyes of 20 donors characterized by ex vivo OCT were analyzed by histology (normal, 4; early/intermediate AMD, 7; geographic atrophy, 6; neovascular AMD, 3). Cryosections were stained with antibodies to retinoid (RPE65, CRALPB) and immune (CD68, CD163) markers. In published RPE cellular phenotypes, red immunoreactivity was assessed semiquantitatively by one observer (none, some cells, all cells).

Results

Plume morphology evolved over time and many resolved (40%). Trajectories of RPE plume and cellular debris paralleled Müller glia, including near atrophy borders. RPE corresponding to HRF lost immunoreactivity for retinoid markers and gained immunoreactivity for immune markers. Aberrant immunoreactivity appeared in individual in-layer RPE cells and extended to all abnormal phenotypes. Müller glia remained CRALBP positive. Plume cells approached and contacted retinal capillaries.

Conclusions

HRF are indicators not predictors of overall disease activity. Gain and loss of function starts with individual in-layer RPE cells and extends to all abnormal phenotypes. Evidence for RPE transdifferentiation, possibly due to ischemia, supports a proposed process of epithelial–mesenchyme transition. Data can propel new biomarkers and therapeutic strategies for AMD.

Correlation of in vivo/ex vivo imaging of the posterior eye segment

BACKGROUND

For an understanding of the pathology of retinal diseases, direct comparisons of high-resolution in vivo retinal imaging and ex vivo histological preparations are desirable.

MATERIAL AND METHODS

Multimodal in vivo and ex vivo imaging of a human donor eye with secondary alterations showing atrophic retina due to central retinal arterial occlusion. The subsequent correlation with the histological examination was carried out on identical tissue localizations.

RESULTS

Appropriate custom-built retinal imaging devices facilitate in vivo and ex vivo correlations and the examination of human eye tissue and acquisition of retinal images, e.g. SD-OCT. The precise alignment of the tissue enables a histological analysis on identical sites.

CONCLUSION

The direct correlation of clinical in vivo imaging with ex vivo imaging including histopathology can further enhance our understanding in the pathogenesis of retinal diseases; however, the proposed method is currently limited due to restricted availability of human donor tissue.

INVESTIGATING A GROWTH PREDICTION MODEL IN ADVANCED AGE-RELATED MACULAR DEGENERATION WITH SOLITARY GEOGRAPHIC ATROPHY USING QUANTITATIVE AUTOFLUORESCENCE

PURPOSE

To investigate geographic atrophy (GA) progression using quantitative autofluorescence (qAF) in eyes with solitary GA.

METHODS

Forty-three eyes of 26 patients (age 79.7 ± 7.2 years; 28 women; 16 pseudophakic) underwent spectral-domain optical coherence tomography and qAF imaging at baseline and after 12 months. The junctional zone (AJZ) and a nonaffected 300-µm-wide control area (AC) were delineated on spectral-domain optical coherence tomography scans and transferred to the qAF image. Linear mixed models were calculated to investigate the association between GA progression and qAF, age, and baseline GA area. Mixed model analyses of variance were used to investigate differences in qAF between areas.

RESULTS

Quantitative autofluorescence of the three inferior sections of both the AJZ (P = 0.028; P = 0.014 and P = 0.032) and the AC (P = 0.043; P = 0.02 and P = 0.028) were significantly associated with GA progression after 12 months. However, qAF measurements were not associated with GA progression in the overall model (P > 0.05). Mean qAF was significantly lower in the AJZ and growth area (AG12) than in the AC (both P ≤ 0.001).

CONCLUSION

The authors report a statistically significant association between GA growth area and qAF measurements at specific retinal locations and a significant difference in qAF between the GA border and unaffected areas outside the lesion. Quantitative autofluorescence measurements may be limitedly useful for predicting GA progression.

Characteristics of normal human retinal pigment epithelium cells with extremes of autofluorescence or intracellular granule count

Background:

Cells of the retinal pigment epithelium (RPE) accumulate different kinds of granules (lipofuscin, melanolipofuscin, melanosomes) within their cell bodies, with lipofuscin and melanolipofuscin being autofluorescent after blue light excitation. High amounts of lipofuscin granules within the RPE have been associated with the development of RPE cell death and age-related macular degeneration (AMD); however, this has not been confirmed in histology so far. Here, based on our previous dataset of RPE granule characteristics, we report the characteristics of RPE cells from human donor eyes that show either high or low numbers of intracellular granules or high or low autofluorescence (AF) intensities.

Methods:

RPE flatmounts of fifteen human donors were examined using high-resolution structured illumination microscopy (HR-SIM) and laser scanning microscopy (LSM). Autofluorescent granules were analyzed regarding AF phenotype and absolute number of granules. In addition, total AF intensity per cell and granule density (number of granules per cell area) were determined. For the final analysis, RPE cells with total granule number below 5^th or above the 95^th percentile, or a total AF intensity ± 1.5 standard deviations above or below the mean were included, and compared to the average RPE cell at the same location. Data are presented as mean ± standard deviation.

Results:

Within 420 RPE cells examined, 42 cells were further analyzed due to extremes regarding total granule numbers. In addition, 20 RPE cells had AF 1.5 standard deviations below, 28 RPE cells above the mean local AF intensity. Melanolipofuscin granules predominate in RPE cells with low granule content and low AF intensity. RPE cells with high granule content have nearly twice (1.8 times) as many granules as an average RPE cell.

Conclusions:

In normal eyes, outliers regarding autofluorescent granule load and AF intensity signals are rare among RPE cells, suggesting that granule deposition and subsequent AF follows intrinsic control mechanisms at a cellular level. The AF of a cell is related to the composition of intracellular granule types. Ongoing studies using AMD donor eyes will examine possible disease related changes in granule distribution and further put lipofuscińs role in aging and AMD further into perspective.

Progression of Atrophy and Visual Outcomes in Extensive Macular Atrophy with Pseudodrusen-like Appearance

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Characterization of Drusen and Hyperreflective Foci as Biomarkers for Disease Progression in Age-Related Macular Degeneration Using Artificial Intelligence in Optical Coherence Tomography

Importance

The morphologic changes and their pathognomonic distribution in progressing age-related macular degeneration (AMD) are not well understood.

Objectives

To characterize the pathognomonic distribution and time course of morphologic patterns in AMD and to quantify changes distinctive for progression to macular neovascularization (MNV) and macular atrophy (MA).

Design, Setting, and Participants

This cohort study included optical coherence tomography (OCT) volumes from study participants with early or intermediate AMD in the fellow eye in the HARBOR (A Study of Ranibizumab Administered Monthly or on an As-needed Basis in Patients With Subfoveal Neovascular Age-Related Macular Degeneration) trial. Patients underwent imaging monthly for 2 years (July 1, 2009, to August 31, 2012) following a standardized protocol. Data analysis was performed from June 1, 2018, to January 21, 2020.

Main Outcomes and Measures

To obtain topographic correspondence between patients and over time, all scans were mapped into a joint reference frame. The time of progression to MNV and MA was established, and drusen volumes and hyperreflective foci (HRF) volumes were automatically segmented in 3 dimensions using validated artificial intelligence algorithms. Topographically resolved population means of these markers were constructed by averaging quantified drusen and HRF maps in the patient subgroups.

Results

Of 1097 patients enrolled in HARBOR, 518 (mean [SD] age, 78.1 [8.2] years; 309 [59.7%] female) had early or intermediate AMD in the fellow eye at baseline. During the 24-month follow-up period, 135 (26%) eyes developed MNV, 50 eyes (10%) developed MA, and 333 (64%) eyes did not progress to advanced AMD. Drusen and HRF had distinct topographic patterns. Mean drusen thickness at the fovea was 29.6 μm (95% CI, 20.2-39.0 μm) for eyes progressing to MNV, 17.2 μm (95% CI, 9.8-24.6 μm) for eyes progressing to MA, and 17.1 μm (95% CI, 12.5-21.7 μm) for eyes without disease progression. At 0.5-mm eccentricity, mean drusen thickness was 25.8 μm (95% CI, 19.1-32.5 μm) for eyes progressing to MNV, 21.7 μm (95% CI, 14.6-28.8 μm) for eyes progressing to MA, and 14.4 μm (95% CI, 11.2-17.6 μm) for eyes without disease progression. The mean HRF thickness at the foveal center was 0.072 μm (95% CI, 0-0.152 μm) for eyes progressing to MNV, 0.059 μm (95% CI, 0-0.126 μm) for eyes progressing to MA, and 0.044 μm (95% CI, 0.007-0.081) for eyes without disease progression. At 0.5-mm eccentricity, the largest mean HRF thickness was seen in eyes progressing to MA (0.227 μm; 95% CI, 0.104-0.349 μm) followed by eyes progressing to MNV (0.161 μm; 95% CI, 0.101-0.221 μm) and eyes without disease progression (0.085 μm; 95% CI, 0.058-0.112 μm).

Conclusions and Relevance

In this study, drusen and HRF represented imaging biomarkers of disease progression in AMD, demonstrating distinct topographic patterns over time that differed between eyes progressing to MNV, eyes progressing to MA, or eyes without disease progression. Automated localization and precise quantification of these factors may help to develop reliable methods of predicting future disease progression.

Geographic Atrophy: Confocal Scanning Laser Ophthalmoscopy, Histology, and Inflammation in the Region of Expanding Lesions

Purpose

To describe the pathology of AMD in eyes with geographic atrophy (GA) using confocal scanning laser ophthalmoscopy (SLO) blue light autofluorescence (BAF), and near-infrared (IR) AF and to correlate it with the histology and immunohistochemistry analysis at the margins of the GA lesion.

Methods

Enucleated, fixed eyes from seventeen donors with GA were imaged and analyzed by BAF-SLO, IRAF-SLO, and by fundus macroscopy (FM). Tissue from the margins of the GA lesions was cut and processed for resin embedding and histology or cryosectioning and fluorescence in the green and far-red channels, and immunohistochemistry to assess markers of inflammation. Isolated DNA from donors was genotyped for single nucleotide polymorphisms (SNPs) previously shown to be risk factors for the development and progression of AMD.

Results

Around the leading edge of the GA lesions we observed hypertrophic RPE cells with cytoplasm filled with granules fluorescent both in the far-red and green-red channels; abundant microglia and macrophage; deposition of complement factor H (CFH) in Bruch's membrane (BM) and increased membrane attack complex (MAC) on RPE cells.

Conclusions

Fluorescence imaging of cryosections of RPE cells around the leading edge of the GA lesions suggest that IRAF-SLO visualizes mostly melanin-related compounds. In addition, medium-size GA atrophy displayed the most significant changes in inflammation markers.

Quantitative Fundus Autofluorescence in Rhesus Macaques in Aging and Age-Related Drusen

Purpose

To employ quantitative fundus autofluorescence (qAF) imaging in rhesus macaques to noninvasively assess retinal pigment epithelial (RPE) lipofuscin in nonhuman primates (NHPs) as a model of aging and age-related macular degeneration (AMD).

Methods

The qAF imaging was performed on eyes of 26 rhesus macaques (mean age 18.8 ± 8.2 years, range 4–27 years) with normal-appearing fundus or with age-related soft drusen using a confocal scanning laser ophthalmoscope with 488 nm excitation and an internal fluorescence reference. Eyes with soft drusen also underwent spectral-domain optical coherence tomography imaging to measure drusen volume and height of individual drusen lesions. The qAF levels were measured from the perifoveal annular ring (quantitative autofluorescence 8 [qAF8]) using the Delori grid, as well as focally over individual drusen lesions in this region. The association between qAF levels and age, sex, and drusen presence and volume were determined using multivariable regression analysis.

Results

Mean qAF levels increased with age (P < 0.001) and were higher in females (P = 0.047). Eyes with soft drusen exhibited reduced mean qAF compared with age-matched normal eyes (P = 0.003), with greater drusen volume showing a trend toward decreased qAF levels. However, qAF levels are focally increased over most individual drusen (P < 0.001), with larger drusen appearing more hyperautofluorescent (R² = 0.391, P < 0.001).

Conclusions

In rhesus macaques, qAF levels are increased with age and female sex, but decreased in eyes with soft drusen, similar to human AMD. However, drusen lesions appear hyperautofluorescent unlike those in humans, suggesting similarities and differences in RPE lipofuscin between humans and NHPs that may provide insight into drusen biogenesis and AMD pathogenesis.

Subretinal Drusenoid Deposits and Photoreceptor Loss Detecting Global and Local Progression of Geographic Atrophy by SD-OCT Imaging

Purpose

To investigate the impact of subretinal drusenoid deposits (SDD) and photoreceptor integrity on global and local geographic atrophy (GA) progression.

Methods

Eighty-three eyes of 49 patients, aged 50 years and older with GA secondary to age-related macular degeneration (AMD), were prospectively included in this study. Participants underwent spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) imaging at baseline and after 12 months. The junctional zone and presence of SDD were delineated on SD-OCT and FAF images. Linear mixed models were calculated to investigate the association between GA progression and the junctional zone area, baseline GA area, age, global and local presence of SDD and unifocal versus multifocal lesions.

Results

The area of the junctional zone was significantly associated with the progression of GA, both globally and locally (all P < 0.001). SDD were associated with faster growth in the overall model (P = 0.039), as well as in the superior-temporal (P = 0.005) and temporal (P = 0.002) sections. Faster progression was associated with GA baseline area (P < 0.001). No difference was found between unifocal and multifocal lesions (P > 0.05). Age did not have an effect on GA progression (P > 0.05).

Conclusions

Photoreceptor integrity and SDD are useful for predicting global and local growth in GA. Investigation of the junctional zone is merited because this area is destined to become atrophic. Photoreceptor loss visible on SD-OCT might lead to new structural outcome measurements visible before irreversible loss of retinal pigment epithelium occurs.

[Correlation of in vivo/ex vivo imaging of the posterior eye segment]

BACKGROUND

For an understanding of the pathology of retinal diseases, direct comparisons of high-resolution in vivo retinal imaging and ex vivo histological preparations are desirable.

MATERIAL AND METHODS

Multimodal in vivo and ex vivo imaging of a human donor eye with secondary alterations showing atrophic retina due to central retinal arterial occlusion. The subsequent correlation with the histological examination was carried out on identical tissue localizations.

RESULTS

Appropriate custom-built retinal imaging devices facilitate in vivo and ex vivo correlations and the examination of human eye tissue and acquisition of retinal images, e.g. SD-OCT. The precise alignment of the tissue enables a histological analysis on identical sites.

CONCLUSION

The direct correlation of clinical in vivo imaging with ex vivo imaging including histopathology can further enhance our understanding in the pathogenesis of retinal diseases; however, the proposed method is currently limited due to restricted availability of human donor tissue.

PROGRESSION OF ABCA4-RELATED RETINOPATHY: Prognostic value of demographic, functional, genetic, and imaging parameters

PURPOSE

To investigate the prognostic value of demographic, functional, genetic, and imaging parameters on retinal pigment epithelium atrophy progression secondary to ABCA4-related retinopathy.

METHODS

Patients with retinal pigment epithelium atrophy secondary to ABCA4-related retinopathy were examined longitudinally with fundus autofluorescence imaging. Lesion area, perimeter, circularity, caliper diameters, and focality of areas with definitely decreased autofluorescence were determined. A model was used to predict the lesion enlargement rate based on baseline variables. Sample size calculations were performed to model the power in a simulated interventional study.

RESULTS

Sixty-eight eyes of 37 patients (age range, 14-78 years) with a follow-up time of 10 to 100 months were included. The mean annual progression of retinal pigment epithelium atrophy was 0.89 mm. The number of atrophic areas, the retina-wide functional impairment, and the age-of-onset category constituted significant predictors for future retinal pigment epithelium atrophy growth, explaining 25.7% of the variability. By extension of a simulated study length and/or specific patient preselection based on these baseline characteristics, the required sample size could significantly be reduced.

CONCLUSION

Trial design based on specific shape-descriptive factors and patients' baseline characteristics and the adaption of the trial duration may provide potential benefits in required cohort size and absolute number of visits.

Structural Features Associated With the Development and Progression of RORA Secondary to Maternally Inherited Diabetes and Deafness

PURPOSE

To investigate the development and progression of retinal pigment epithelial and outer retinal atrophy (RORA) secondary to maternally inherited diabetes and deafness (MIDD).

DESIGN

Retrospective observational case series.

METHODS

Thirty-six eyes of 18 patients (age range, 22.4-71.6 years) with genetically proven MIDD and serial optical coherence tomography (OCT) images were included. As proposed reference standard to diagnose and stage atrophy, OCT images were longitudinally evaluated and analyzed for presence and precursors of RORA. RORA was defined as an area of (1) hypertransmission, (2) disruption of the retinal pigment epithelium, (3) photoreceptor degeneration, and (4) absence of other signs of a retinal pigment epithelial tear.

RESULTS

The majority of patients revealed areas of RORA in a circular area around the fovea of between 5° and 15° eccentricity. Over the observation time (range, 0.5-8.5 years), evidence for a consistent sequence of OCT features from earlier disease stages to the end stage of RORA could be found, starting with loss of ellipsoid zone and subretinal deposits, followed by loss of external limiting membrane and loss of retinal pigment epithelium with hypertransmission of OCT signal into the choroid, and leading to loss of the outer nuclear layer bordered by hyporeflective wedges. Outer retinal tabulations seemed to develop in regions of coalescent areas of RORA.

CONCLUSIONS

The development and progression of RORA could be tracked in MIDD patients using OCT images, allowing potential definition of novel surrogate markers. Similarities to OCT features in age-related macular degeneration, where mitochondrial dysfunction has been implicated in the pathogenesis, support wide-ranging benefits from proof-of-concept studies in MIDD.

Modulation of Tmem135 Leads to Retinal Pigmented Epithelium Pathologies in Mice

Purpose

Aging is a critical risk factor for the development of retinal diseases, but how aging perturbs ocular homeostasis and contributes to disease is unknown. We identified transmembrane protein 135 (Tmem135) as a gene important for regulating retinal aging and mitochondrial dynamics in mice. Overexpression of Tmem135 causes mitochondrial fragmentation and pathologies in the hearts of mice. In this study, we examine the eyes of mice overexpressing wild-type Tmem135 (Tmem135 TG) and compare their phenotype to Tmem135 mutant mice.

Methods

Eyes were collected for histology, immunohistochemistry, electron microscopy, quantitative PCR, and Western blot analysis. Before tissue collection, electroretinography (ERG) was performed to assess visual function. Mouse retinal pigmented epithelium (RPE) cultures were established to visualize mitochondria.

Results

Pathologies were observed only in the RPE of Tmem135 TG mice, including degeneration, migratory cells, vacuolization, dysmorphogenesis, cell enlargement, and basal laminar deposit formation despite similar augmented levels of Tmem135 in the eyecup (RPE/choroid/sclera) and neural retina. We observed reduced mitochondria number and size in the Tmem135 TG RPE. ERG amplitudes were decreased in 365-day-old mice overexpressing Tmem135 that correlated with reduced expression of RPE cell markers. In Tmem135 mutant mice, RPE cells are thicker, smaller, and denser than their littermate controls without any signs of degeneration.

Conclusions

Overexpression and mutation of Tmem135 cause contrasting RPE abnormalities in mice that correlate with changes in mitochondrial shape and size (overfragmented in TG vs. overfused in mutant). We conclude proper regulation of mitochondrial homeostasis by TMEM135 is critical for RPE health.

Relationship between morphological and vascular alterations in geographic atrophy using a multimodal imaging approach

PURPOSE

To assess geographic atrophy (GA) using a multimodal imaging approach, focusing on alterations at the level of the retinal pigment epithelium (RPE) and the choriocapillaris (CC) layers, by lesion demarcation, and assessment of morphological alterations within the atrophic area and in the transition zone.

METHODS

Fifty-seven eyes of 34 patients with atrophic age-related macular degeneration (AMD) were included in this prospective, observational, cross-sectional study. Multimodal imaging using wide-field polarization-sensitive optical coherence tomography (PS-OCT), optical coherence tomography angiography (OCT-A) and fundus autofluorescence (FAF) was performed. The images were overlaid and used to analyse and compare alterations in the retina and the CC.

RESULTS

Mean atrophic lesion size was 8.15 mm² (range: 2.23-17.23 mm² ). In 52 of 57 eyes (91%), OCT-A displayed focal hypodense areas at the CC level in the transition zone of GA, as well as increased focal depolarizing material (e.g. melanin-containing structures) showed in PS-OCT en face depolarizing material maps. These regions of increased depolarizing material at the transition zone corresponded to the hypodense areas on OCT-A scans. All 57 eyes presented with abnormal FAF patterns at the transition zone. All 57 eyes showed distinct alterations of CC flow pattern architecture. Six eyes (11%) demonstrated reduced and three eyes (5%) a complete loss of CC flow pattern architecture across the entire area of GA, while 48 of 57 eyes (84%) presented with irregular mixed patterns of different focal alterations of CC flow architecture within the area of GA. Reduced CC patterns exceeding GA lesion margins into the transitional zone were found in all eyes.

CONCLUSIONS

Optical coherence tomography angiography images revealed different degrees of flow impairment within the atrophic lesion area and its transition zone. Alterations in RPE morphology and tissue integrity resulting in accumulation of depolarizing material, such as melanin, could result in misinterpretation of OCT-A imaging in areas in the shadow of depolarizing material. These changes seem to be partially independent from autofluorescence altering processes.

The In Vivo Correlation between Retinal Pigment Epithelium Thickness and Quantitative Fundus Autofluorescence in a White Population

PURPOSE

To investigate the influence of age on the thickness of the retinal pigment epithelium (RPE)/Bruch's membrane (BM) complex and the quantitative autofluorescence (qAF) and to study the possible correlation existing between these 2 parameters in a healthy White population.

DESIGN

Cross-sectional, observational study.

PARTICIPANTS

Healthy White volunteers aged 18 to 65 years.

METHODS

All subjects underwent spectral domain OCT (SD-OCT) and qAF imaging with the Heidelberg HRA-Spectralis (Heidelberg Engineering, Heidelberg, Germany). Spectral domain OCT images were analyzed using the in-built graph-based automatic segmentation algorithm for single retinal layer identification to assess RPE/BM complex thickness in vivo. The thickness values of both inner and outer rings of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid, generated by the software using the "RPE" segmentation, were averaged to obtain a single RPE/BM complex thickness value in each eye. Quantitative autofluorescence images were also evaluated using a dedicated software. The qAF values of 8 subfields forming a ring centered onto the fovea were collected and averaged to obtain a single qAF value (qAF₈) in each eye. The correlation among the RPE/BM complex thickness, the qAF value, and the age of the subjects was investigated.

MAIN OUTCOME MEASURES

The in vivo correlation between RPE/BM complex thickness and qAF.

RESULTS

A total of 105 eyes from 105 subjects (mean age, 42.1 ± 13.9 years; range, 18-65) were included in the analysis. The mean RPE/BM complex thickness significantly increased with age (r = 0.33, P = 0.0006). The values of qAF also positively increased with age (P < 0.0001). A significant correlation was found between qAF and RPE/BM complex thickness (r = 0.27, P = 0.004). After adjusting for age, iris color, and gender, the correlation remained significant only for subjects aged less than 40 years (P = 0.009).

CONCLUSIONS

BM complex thickness was significantly co/BM complex thickness increased with age in a healthy White population. A similar increase was found for qAF values. After adjusting for age and iris color, qAF and RPE/BM complex thickness were still correlated in subjects aged less than 40 years. The RPE/BM complex thickness could reflect the lipofuscin/melanolipofuscin accumulation in normal subjects, adding great interest in RPE cell biology.

Systemic Treatment With Nicotinamide Riboside Is Protective in a Mouse Model of Light-Induced Retinal Degeneration

Purpose

Maintaining levels of nicotinamide adenine dinucleotide (NAD+), a coenzyme critical for cellular energetics and biosynthetic pathways, may be therapeutic in retinal disease because retinal NAD+ levels decline during retinal damage and degeneration. The purpose of this study was to investigate whether systemic treatment with nicotinamide riboside (NR), a NAD+ precursor that is orally deliverable and well-tolerated by humans, is protective in a mouse model of light-induced retinal degeneration.

Methods

Mice were injected intraperitoneally with vehicle or NR the day before and the morning of exposure to degeneration-inducing levels of light. Retinal function was assessed by electroretinography and in vivo retinal morphology and inflammation was assessed by optical coherence tomography. Post mortem retina sections were assessed for morphology, TUNEL, and inflammatory markers Iba1 and GFAP. Retinal NAD+ levels were enzymatically assayed.

Results

Exposure to degeneration-inducing levels of light suppressed retinal NAD+ levels. Mice undergoing light-induced retinal degeneration exhibited significantly suppressed retinal function, severely disrupted photoreceptor cell layers, and increased apoptosis and inflammation in the outer retina. Treatment with NR increased levels of NAD+ in retina and prevented these deleterious outcomes.

Conclusions

This study is the first to report the protective effects of NR treatment in a mouse model of retinal degeneration. The positive outcomes, coupled with human tolerance to NR dosing, suggest that maintaining retinal NAD+ via systemic NR treatment should be further explored for clinical relevance.

Role of Deep Learning-Quantified Hyperreflective Foci for the Prediction of Geographic Atrophy Progression

PURPOSE

To quantitatively measure hyperreflective foci (HRF) during the progression of geographic atrophy (GA) secondary to age-related macular degeneration (AMD) using deep learning (DL) and investigate the association with local and global growth of GA.

METHODS

Eyes with GA were prospectively included. Spectral-domain optical coherence tomography (SDOCT) and fundus autofluorescence images were acquired every 6 months. A 500-μm-wide junctional zone adjacent to the GA border was delineated and HRF were quantified using a validated DL algorithm. HRF concentrations in progressing and nonprogressing areas, as well as correlations between HRF quantifications and global and local GA progression, were assessed.

RESULTS

A total of 491 SDOCT volumes from 87 eyes of 54 patients were assessed with a median follow-up of 28 months. Two-thirds of HRF were localized within a millimeter adjacent to the GA border. HRF concentration was positively correlated with GA progression in unifocal and multifocal GA (all P < .001) and de novo GA development (P = .037). Local progression speed correlated positively with local increase of HRF (P value range <.001-.004). Global progression speed, however, did not correlate with HRF concentrations (P > .05). Changes in HRF over time did not have an impact on the growth in GA (P > .05).

CONCLUSION

Advanced artificial intelligence (AI) methods in high-resolution retinal imaging allows to identify, localize, and quantify biomarkers such as HRF. Increased HRF concentrations in the junctional zone and future macular atrophy may represent progressive migration and loss of retinal pigment epithelium. AI-based biomarker monitoring may pave the way into the era of individualized risk assessment and objective decision-making processes. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Recognizing Atrophy and Mixed-Type Neovascularization in Age-Related Macular Degeneration Via Clinicopathologic Correlation

Purpose

We explored via multimodal imaging and histology an eye with mixed-types 1 and 2 macular neovascularization (MNV) and complete retinal pigment epithelium (RPE) and outer retinal atrophy (cRORA) in age-related macular degeneration.

Methods

An 82-year-old white man was followed 7 years by optical coherence tomography and treated with intravitreal anti-vascular endothelial growth factor for 3 years. At the last clinic visit, visual acuity was stable at 20/50. Two months later the patient died, and eyes were preserved at 8.33 hours after death. Submicrometer epoxy resin sections of osmicated tissue were stained with toluidine blue and evaluated by oil immersion microscopy.

Results

A shallow irregular RPE elevation on optical coherence tomography correlated with type 1 MNV with fibrocellular scar and neocapillaries (close to RPE), at a density similar to underlying native choriocapillaris (0.37 vs. 0.42). Type 2 MNV covered the native RPE and was enveloped at the margins by RPE, without neocapillaries. Native RPE cells transdifferentiated from age-normal to melanotic and entered type 1 MNV and choroid. Some photoreceptors persisted over MNV. The cRORA initiated at a collapsed druse, expanded during follow-up, and exhibited low choriocapillaris density (0.05).

Conclusions

An eye with maintained vision on 3 years of anti-vascular endothelial growth factor therapy had type 1 MNV sustaining RPE. Type 2 MNV enveloped by RPE was visible in optical coherence tomography and histology. Persistence of photoreceptors and RPE over MNV contrasted with drusen-associated cRORA.

Translational Relevance

Vision during long-term anti-vascular endothelial growth factor treatment persists by MNV partially preserving outer retinal cells and by RPE enveloping type 2 MNV.

Nanoceria Particles Are an Eligible Candidate to Prevent Age-Related Macular Degeneration by Inhibiting Retinal Pigment Epithelium Cell Death and Autophagy Alterations

Retinal pigment epithelium (RPE) dysfunction and degeneration underlie the development of age-related macular degeneration (AMD), which is the leading cause of blindness worldwide. In this study, we investigated whether cerium oxide nanoparticles (CeO₂-NPs or nanoceria), which are anti-oxidant agents with auto-regenerative properties, are able to preserve the RPE. On ARPE-19 cells, we found that CeO₂-NPs promoted cell viability against H₂O₂-induced cellular damage. For the in vivo studies, we used a rat model of acute light damage (LD), which mimics many features of AMD. CeO₂-NPs intravitreally injected three days before LD prevented RPE cell death and degeneration and nanoceria labelled with fluorescein were found localized in the cytoplasm of RPE cells. CeO₂-NPs inhibited epithelial-mesenchymal transition of RPE cells and modulated autophagy by the down-regulation of LC3B-II and p62. Moreover, the treatment inhibited nuclear localization of LC3B. Taken together, our study demonstrates that CeO₂-NPs represent an eligible candidate to counteract RPE degeneration and, therefore, a powerful therapy for AMD.

Progression of Retinopathy Secondary to Maternally Inherited Diabetes and Deafness - Evaluation of Predicting Parameters

PURPOSE

To investigate the prognostic value of demographic, functional, and imaging parameters on retinal pigment epithelium (RPE) atrophy progression secondary to maternally inherited diabetes and deafness (MIDD) and to evaluate the application of these factors in clinical trial design.

DESIGN

Retrospective observational case series.

METHODS

Thirty-five eyes of 20 patients (age range, 24.9-75.9 years) with genetically proven MIDD and demarcated RPE atrophy on serial fundus autofluorescence (AF) images were included. Lesion size and shape-descriptive parameters were longitudinally determined by 2 independent readers. A linear mixed-effect model was used to predict the lesion enlargement rate based on baseline variables. Sample size calculations were performed to model the power in a simulated interventional study.

RESULTS

The mean follow-up time was 4.27 years. The mean progression rate of RPE atrophy was 2.33 mm²/year, revealing a dependence on baseline lesion size (+0.04 [0.02-0.07] mm²/year/mm², P < .001), which was absent after square root transformation. The fovea was preserved in the majority of patients during the observation time. In the case of foveal involvement, the loss of visual acuity lagged behind central RPE atrophy in AF images. Sex, age, and number of atrophic foci predicted future progression rates with a cross-validated mean absolute error of 0.13 mm/year and to reduce the required sample size for simulated interventional trials.

CONCLUSIONS

Progressive RPE atrophy could be traced in all eyes using AF imaging. Shape-descriptive factors and patients' baseline characteristics had significant prognostic value, guiding appropriate subject selection and sample size in future interventional trial design.

CLINICOPATHOLOGIC CORRELATION OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION

Supplemental Digital Content is Available in the Text.

Direct clinicopathologic correlation of an eye with geographic atrophy secondary to age-related macular degeneration provides histologic correlates of features commonly seen by optical coherence tomography, such as end-stages of drusen, subretinal drusenoid deposit, plaques near the Bruch membrane, and hyporeflective wedge.

Purpose:

In an eye with geographic atrophy (GA) secondary to age-related macular degeneration, we correlated ex vivo histologic features with findings recorded in vivo using optical coherence tomography (OCT), near-infrared reflectance imaging, and fundus autofluorescence.

Methods:

In the left eye of an 86-year-old white woman, in vivo near-infrared reflectance and eye-tracked OCT B-scans at each of 6 clinic visits and a baseline fundus autofluorescence image were correlated with high-resolution histologic images of the preserved donor eye.

Results:

Clinical imaging showed a small parafoveal multilobular area of GA, subfoveal soft drusen, refractile drusen, hyperreflective lines near the Bruch membrane, subretinal drusenoid deposit (reticular pseudodrusen), and absence of hyperautofluorescent foci at the GA margin. By histology, soft drusen end-stages included avascular fibrosis with highly reflective cholesterol crystals. These accounted for hyperreflective lines near the Bruch membrane in OCT and plaques in near-infrared reflectance imaging. Subretinal drusenoid deposit was thick, continuous, extracellular, extensive outside the fovea, and associated with distinctive retinal pigment epithelium dysmorphia and photoreceptor degeneration. A hyporeflective wedge corresponded to ordered Henle fibers without cellular infiltration. The external limiting membrane descent, which delimits GA, was best visualized in high-quality OCT B-scans. Retinal pigment epithelium and photoreceptor changes at the external limiting membrane descent were consistent with our recent histologic survey of donor eyes.

Conclusion:

This case informs on the extent, topography, and lifecycle of extracellular deposits. High-quality OCT scans are required to reveal all tissue features relevant to age-related macular degeneration progression to GA, especially the external limiting membrane descent. Histologically validated signatures of structural OCT B-scans can serve as references for other imaging modalities.

Selective Ablation of Dehydrodolichyl Diphosphate Synthase in Murine Retinal Pigment Epithelium (RPE) Causes RPE Atrophy and Retinal Degeneration

Patients with certain defects in the dehydrodolichyl diphosphate synthase (DHDDS) gene (RP59; OMIM #613861) exhibit classic symptoms of retinitis pigmentosa, as well as macular changes, suggestive of retinal pigment epithelium (RPE) involvement. The DHDDS enzyme is ubiquitously required for several pathways of protein glycosylation. We wish to understand the basis for selective ocular pathology associated with certain DHDDS mutations and the contribution of specific ocular cell types to the pathology of mutant Dhdds-mediated retinal degeneration. To circumvent embryonic lethality associated with Dhdds knockout, we generated a Cre-dependent knockout allele of murine Dhdds (Dhddsflx/flx). We used targeted Cre expression to study the importance of the enzyme in the RPE. Structural alterations of the RPE and retina including reduction in outer retinal thickness, cell layer disruption, and increased RPE hyper-reflectivity were apparent at one postnatal month. At three months, RPE and photoreceptor disruption was observed non-uniformly across the retina as well as RPE transmigration into the photoreceptor layer, external limiting membrane descent towards the RPE, and patchy loss of photoreceptors. Functional loss measured by electroretinography was consistent with structural loss showing scotopic a- and b-wave reductions of 83% and 77%, respectively, at three months. These results indicate that RPE dysfunction contributes to DHDDS mutation-mediated pathology and suggests a more complicated disease mechanism than simply disruption of glycosylation.

Macular hole and serous pigment epithelial detachment in bilateral acquired vitelliform lesions

Purpose

Acquired vitelliform lesions (AVLs) are associated with age-related macular degeneration and other variable macular disorders. AVLs often lead to outer retinal atrophy, sometimes accompanying a macular hole and choroidal neovascularization. The purpose of this study was to report a rare case with bilateral AVLs, in which one eye had accompanied a macular hole and the second eye a serous pigment epithelial detachment (sPED).

Observations

A 66-year-old woman complained of bilateral metamorphopsia. AVLs were observed in the right eye and a flat sPED in the left eye. The best-corrected visual acuity (BCVA) was 20/17 in both eyes. Fluorescein angiography revealed local leakage in the right eye and pattern dystrophy-like hypofluorescence in both eyes. The sPED progressed with AVLs in the left eye and was treated with a combination therapy of intravitreal aflibercept, a sub-Tenon's injection of triamcinolone acetonide, and photodynamic therapy (IVA/STTA/PDT), which successfully flattened the sPED and sustained good vision for 4 years. The right eye was treated with intravitreal ranibizumab and tissue plasminogen activator, which enhanced absorption of the vitelliform material. However, 14 months later, a macular hole with typical metamorphopsia formed above a subretinal fibrotic scar at the vitelliruptive stage. Although pars plana vitrectomy closed the macular hole, enlargement of the outer retinal atrophy worsened the BCVA to 20/100.

Conclusions and importance

We successfully treated one eye with a sPED with AVLs using the combination therapy of IVA/STTA/PDT, while the second eye with a macular hole secondary to AVLs ultimately developed outer retinal atrophy with visual loss.

Relationship between proximity of choriocapillaris flow deficits and enlargement rate of geographic atrophy

PURPOSE

To correlate choriocapillaris (CC) flow deficits (FD) in eyes with geographic atrophy (GA) at various distances from the border of the GA lesion with yearly enlargement rate (yER) of GA.

METHODS

In this retrospective study, spectral domain optical coherence tomography (SD-OCT) and SD optical coherence tomography angiography (OCTA) images were collected from patients with GA, who were imaged at Doheny Eye Centers between 2016 and 2018, using the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). All enrolled patients had one baseline 6 × 6 mm OCTA scan and two 6 × 6 mm SD-OCT cubes, one at baseline and one at a follow-up visit at least 12 months later. The border of the GA was manually outlined on the en face OCT fundus image and the yER was calculated after square root transformation. A grid composed of 100-μm-wide successive concentric rings was created around the GA lesion on the OCTA CC slab using ImageJ and the FD% was calculated from the binarized image. FD% from each ring was correlated with the yER of GA.

RESULTS

Thirty eyes of 22 patients were included in the study. The mean yER was 0.2 ± 0.15 mm. The FD% in the first five rings (from 0 to 500 μm from the border of GA) was significantly correlated with the yER. However, there was no statistically significant correlation between the yER and CC FD% beyond 500 μm from the GA lesion.

CONCLUSIONS

Only the choriocapillaris FD% in the 500-μm region immediately surrounding GA lesions appears to predict the rate of enlargement of these lesions.