Geographic Atrophy and Choroidal Neovascularization in the Same Eye: A Review

Pre-Clinical Studies of a Novel Bispecific Fusion Protein Targeting C3b and VEGF in Neovascular and Nonexudative AMD Models

INTRODUCTION

KNP-301 is a bi-specific fragment crystallizable region (Fc) fusion protein, which inhibits both C3b and vascular endothelial growth factor (VEGF) simultaneously for patients with late-stage age-related macular degeneration (AMD). The present study evaluated in vitro potency, in vivo efficacy, intravitreal pharmacokinetics (IVT PK), and injectability of KNP-301.

METHODS

C3b and VEGF binding of KNP-301 were assessed by surface plasmon resonance (SPR) and enzyme-linked immunosorbent assay (ELISA), and cellular bioassays. A laser-induced choroidal neovascularization (CNV) model and a sodium iodate-induced nonexudative AMD model were used to test the in vivo efficacy of mouse surrogate of KNP-301. Utilizing fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT) scans, the reduction in disease lesions were analyzed in a CNV mouse model. In the nonexudative AMD mouse model, outer nuclear layer (ONL) was assessed by immunofluorescence staining. Lastly, intravitreal pharmacokinetic study was conducted with New Zealand white rabbits via IVT administration of KNP-301 and injectability of KNP-301 was examined by a viscosity test at high concentrations.

RESULTS

KNP-301 bound C3b selectively, which resulted in a blockade of the alternative pathway, not the classical pathway. KNP-301 also acted as a VEGF trap, impeding VEGF-mediate signaling. Our dual-blockade strategy was effective in both neovascular and nonexudative AMD models. Moreover, KNP-301 had an advantage of potentially less frequent dosing due to the long half-life in the intravitreal chamber. Our viscosity assessment confirmed that KNP-301 meets the criteria of the IVT injection.

CONCLUSIONS

Unlike current therapies, KNP-301 is expected to cover patients with late-stage AMD of both neovascular and nonexudative AMD, and its long-term PK profile at the intravitreal chamber would allow convenience in the dosing interval of patients.

Naevi Characterization Using Hyperspectral Imaging: A Pilot Study

PURPOSE

The prevalence of choroidal naevi is common and has been found to be up to 10%. Little is known regarding the optical properties of choroidal naevi. A novel hyperspectral eye fundus camera was used to investigate choroidal naevi's optical density spectra in the retina.

METHODS

In an ophthalmology clinic setting, patients with choroidal naevi were included in the study. Visual acuity and pressure were tested. Following mydriatics, optical coherence tomography and fundus photography were taken as a reference, after which a hyperspectral image with 12 nm spectral resolution at 450-700 nm was taken. The optical density spectra was measured across the area of the naevus.

RESULTS

Nine patients with 11 naevi were examined. The visual acuity was not affected by any of the naevi. All the naevi were flat as measured either with the optical coherence tomography and/or on inspection, and only one naevi had a risk factor (orange pigmentation). The Wasserstein distance between the background and the naevi was higher at 695 nm compared to 555 nm (p = .002). The naevi could be grouped into three clusters based on the extracted optical density spectra.

CONCLUSION

Choroidal naevi are better visible in longer wavelengths compared to shorter wavelengths. This finding can be used to contour and follow choroidal naevi. Choroidal naevi expose different optical density spectra that can be grouped into three different clusters. One of these clusters has an optical density spectra resembling the absorption spectra of lipofuscin, which may indicate the content of this pigment.

Gene Therapy for Non-Hereditary Retinal Disease: Age-Related Macular Degeneration, Diabetic Retinopathy, and Beyond

Gene therapy holds promise as a transformative approach in the treatment landscape of age-related macular degeneration (AMD), diabetic retinopathy (DR), and diabetic macular edema (DME), aiming to address the challenges of frequent intravitreal anti-vascular endothelial growth factor (VEGF) injections. This manuscript reviews ongoing gene therapy clinical trials for these disorders, including ABBV-RGX-314, ixoberogene soroparvovec (ixo-vec), and 4D-150. ABBV-RGX-314 utilizes an adeno-associated virus (AAV) vector to deliver a transgene encoding a ranibizumab-like anti-VEGF antibody fragment, demonstrating promising results in Phase 1/2a and ongoing Phase 2b/3 trials. Ixo-vec employs an AAV2.7m8 capsid for intravitreal delivery of a transgene expressing aflibercept, showing encouraging outcomes in Phase 1 and ongoing Phase 2 trials. 4D-150 utilizes an evolved vector to express both aflibercept and a VEGF-C inhibitory RNAi, exhibiting positive interim results in Phase 1/2 studies. Other therapies reviewed include EXG102-031, FT-003, KH631, OLX10212, JNJ-1887, 4D-175, and OCU410. These therapies offer potential advantages of reduced treatment frequency and enhanced safety profiles, representing a paradigm shift in management towards durable and efficacious cellular-based biofactories. These advancements in gene therapy hold promise for improving outcomes in AMD and addressing the complex challenges of DME and DR, providing new avenues for the treatment of diabetic eye diseases.

Advanced age-related macular degeneration and risk factors in eyes with pachydrusen

The risk of progression to advanced age-related macular degeneration (AMD) varies depending on the type of drusen. This retrospective longitudinal study included 248 eyes of 156 patients with pachydrusen without advanced AMD at baseline. Macular neovascularization (MNV) and geographic atrophy (GA) were evaluated. Risk factors for progression to advanced AMD were determined using multivariate Cox regression analysis. The mean age at baseline was 65.4 ± 9.1 years, and the mean follow-up duration was 6.40 ± 3.58 years. The mean total number of pachydrusen and macular pachydrusen were 4.10 ± 2.85 and 2.27 ± 1.81 per eye, respectively. Pachydrusen was accompanied by other types of drusen in 4.8% (12 eyes) of eyes at baseline. During follow-up, MNVs occurred in 2.8% (seven eyes), including polypoidal choroidal vasculopathy (PCV six eyes); however, no GA occurred. Regarding risk factors for progression to neovascular AMD, age (p = 0.023) and macular pigmentary changes (p = 0.014) were significantly associated with MNV development. The cumulative incidence of MNV was significantly higher in the group with macular pigmentary changes (17.39% vs. 0.57% at 10 years; p = 0.0005). The number of macular pachydrusen and the presence of MNV in the fellow eye did not show a statistically significant relationship with MNV development. Age and macular pigmentary changes are risk factors for MNV development in the eyes with pachydrusen. Eyes with pachydrusen appear to have a risk profile for advanced AMD that is different from that of AMD eyes with drusen or drusenoid deposits other than pachydrusen.

AAV-Based Strategies for Treatment of Retinal and Choroidal Vascular Diseases: Advances in Age-Related Macular Degeneration and Diabetic Retinopathy Therapies

Age-related macular degeneration (AMD) and diabetic retinopathy (DR) are vascular diseases with high prevalence, ranking among the leading causes of blindness and vision loss worldwide. Despite being effective, current treatments for AMD and DR are burdensome for patients and clinicians, resulting in suboptimal compliance and real risk of vision loss. Thus, there is an unmet need for long-lasting alternatives with improved safety and efficacy. Adeno-associated virus (AAV) is the leading vector for ocular gene delivery, given its ability to enable long-term expression while eliciting relatively mild immune responses. Progress has been made in AAV-based gene therapies for not only inherited retinal diseases but also acquired conditions with preclinical and clinical studies of AMD and DR showing promising results. These studies have explored several pathways involved in the disease pathogenesis, as well as different strategies to optimise gene delivery. These include engineered capsids with enhanced tropism to particular cell types, and expression cassettes incorporating elements for a targeted and controlled expression. Multiple-acting constructs have also been investigated, in addition to gene silencing and editing. Here, we provide an overview of strategies employing AAV-mediated gene delivery to treat AMD and DR. We discuss preclinical efficacy studies and present the latest data from clinical trials for both diseases.

Progression of Geographic Atrophy: Retrospective Analysis of Patients from the IRIS® Registry (Intelligent Research in Sight)

Purpose

To evaluate disease progression and associated vision changes in patients with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) in 1 eye and GA or neovascular AMD (nAMD) in the fellow eye using a large dataset from routine clinical practice.

Design

Retrospective analysis of clinical data over 24 months.

Subjects

A total of 256 635 patients with GA from the American Academy of Ophthalmology (Academy) IRIS® Registry (Intelligent Research in Sight) Registry (January 2016 to December 2017).

Methods

Patients with ≥ 24 months of follow-up were grouped by fellow-eye status: Cohort 1, GA:GA; Cohort 2, GA:nAMD, each with (subfoveal) and without subfoveal (nonsubfoveal) involvement. Eyes with history of retinal disease other than AMD were excluded. Sensitivity analysis included patients who were managed by retina specialists and had a record of imaging within 30 days of diagnosis.

Main Outcome Measures

Change in visual acuity (VA), occurrence of new-onset nAMD, and GA progression from nonsubfoveal to subfoveal.

Results

In total, 69 441 patients were included: 44 120 (64%) GA:GA and 25 321 (36%) GA:nAMD. Otherwise eligible patients (57 788) were excluded due to follow-up < 24 months. In both GA:GA and GA:nAMD cohorts, nonsubfoveal study eyes had better mean (standard deviation) VA at index (67 [19.3] and 66 [20.3] letters) than subfoveal eyes (59 [23.9] and 47 [26.9] letters), and 24-month mean VA changes were similar for nonsubfoveal (-7.6 and -6.2) and subfoveal (-7.9 and -6.5) subgroups. Progression to subfoveal GA occurred in 16.7% of nonsubfoveal study eyes in the GA:GA cohort and 12.5% in the GA:nAMD cohort. More new-onset study-eye nAMD was observed in the GA:nAMD (21.6%) versus GA:GA (8.2%) cohorts. Sensitivity analysis supported the robustness of the observations in the study.

Conclusions

This retrospective analysis describes the natural progression of GA lesions and the decline in VA associated with the disease.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Diagnosis and Management of Patients With Geographic Atrophy Secondary to Age-Related Macular Degeneration: A Delphi Consensus Exercise

Geographic atrophy (GA) is a progressive and irreversible retinal disease with no comprehensive recommendations for diagnosis or monitoring. We used a Delphi approach to determine consensus in key areas around diagnosis and management of GA. A steering committee of eight retina specialists developed two sequential online surveys administered to eye care professionals (ECPs). Consensus was defined as agreement by ≥ 75% of respondents. Up to 177 ECPs from eight countries completed one or both surveys. Consensus was achieved in several topics related to diagnostic imaging, including the use of optical coherence tomography, and the urgent need for treatments and beneficial interventions to reduce the associated burden. Currently, low-vision aids and smoking cessation are considered the most beneficial interventions. We demonstrate consensus for diagnosis and management of patients with GA including best practices in patient identification and monitoring, and unmet needs. [Ophthalmic Surg Lasers Imaging Retina 2023;54:589-598.].

Vessel density changes in choroid, chorio-capillaries, deep and superficial retinal plexues on OCTA in normal ageing and various stages of age-related macular degeneration

PURPOSE

To study vessel density (VD) on optical coherence tomography angiography at choroid, chorio-capillaries (CC) and various retinal levels in normal population and various stages of dry AMD and how these changes progress with increase in severity of the disease.

METHODS

Prospective, observational, cross-sectional study was done on 252 eyes of 132 patients (males: 61, females: 71) presenting to tertiary-care centre in Central India between February 2021 and January 2022. For study purpose, eyes were divided into five groups according to the size and number of the drusen, viz, Group 1: No AMD (< 50 years), Group 2: No AMD (> 50 years), Group 3: Early AMD, Group 4: Intermediate AMD and Group 5: Advanced AMD. In all eyes, VD was measured at choroid, CC, deep capillary plexus (DCP) of retina and superficial capillary plexus (SCP) of retina.

RESULTS

The mean age in case cohort is 61.90 ± 7.97 years. The mean vascular density differed significantly across diagnosis types in all the quadrants (p < 0.05) at choroid, CC and DCP level. At SCP level, the differences were significant across the groups except at the central quadrant. Vessel density was found to be more in early AMD cohort when compared to No AMD (> 50 years) cohort at SCP and DCP level, while it showed continuous reduction later in intermediate and advanced AMD cohort.

CONCLUSION

With increase in the severity of disease, significant reduction in VD is also seen in retinal plexuses, along with the changes in choroid and CC. These VD maps may play a role as non-invasive biomarkers for healthy and diseased ageing.

Geographic atrophy: Mechanism of disease, pathophysiology, and role of the complement system

Geographic atrophy (GA) is an advanced form of age-related macular degeneration (AMD), characterized by atrophic lesions that first start in the outer retina and progressively expand to cover the macula and the fovea, the center of the macula, leading to irreversible loss of vision over time. GA is distinct from wet or neovascular AMD (nAMD), the other form of advanced AMD. Neovascular AMD is characterized by new invading leaky blood vessels in the macula that can lead to acute vision loss. GA and nAMD may coexist in the same eye. The underlying pathophysiology of GA is complex and thought to involve chronic inflammation due to overactivation of the complement system that leads to the loss of photoreceptors, retinal pigment epithelium (RPE), and the underlying choriocapillaris. The disappearance of these structures appears as sharply demarcated atrophic lesions that are typical of GA. Researchers have reported about 1 million reported cases of GA in the United States, and about 160,000 cases occur per year. The most important risk factors for GA are increasing age and family history. Diagnosis of GA is usually made by using multimodal imaging techniques. Lesions associated with GA are highly heterogeneous, and the growth rate may differ from patient to patient. Despite the progressive nature of GA, the fovea may be spared until much later in the disease, thereby retaining central vision in patients. With time, atrophic lesions may progressively grow to involve the fovea, thereby severely impairing central vision. Vision loss can happen rapidly once the lesions reach the fovea. However, even without the involvement of the fovea, ongoing vision impairment impacting daily life may be present. Median time from GA not involving the center of the fovea (without subfoveal involvement) to GA with lesion boundary affecting the foveal center (subfoveal involvement) ranges from 1.4 to 2.5 years. GA can greatly impact patients' functioning and quality of life and limit their independence by interfering with activities of daily living, including difficulties with reading, driving, watching television, recognizing faces, and being unable to do household chores. No treatments have been available until intravitreal pegcetacoplan was recently approved by the US Food and Drug Administration for GA secondary to AMD. DISCLOSURES: Dr Bakri serves as a consultant to Apellis Pharmaceuticals, as well as AbbVie, Adverum, Eyepoint, iLumen, Iveric Bio, Genentech, Novartis, Outlook Therapeutics, Pixium, Regeneron, Roche, and Regenxbio. Drs Sharp, Luo, and Sarda are employees of Apellis Pharmaceuticals. Dr Bektas and Ms Khan are employees of RTI Health Solutions. Apellis developed and led the concept design of this publication, review and interpretation, approval, and decision to publish. This research was developed under a research contract between RTI Health Solutions and Apellis Pharmaceuticals and was funded by Apellis Pharmaceuticals. This supplement is to describe the disease of geographic atrophy and was funded by Apellis. Apellis Pharmaceuticals has developed Syfovre (pegcetacoplan), the first and only treatment for geographic atrophy.

Clinicopathologic Findings in Three Siblings With Geographic Atrophy

Purpose

Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly worldwide. Clinical imaging and histopathologic studies are crucial to understanding disease pathology. This study combined clinical observations of three brothers with geographic atrophy (GA), followed for 20 years, with histopathologic analysis.

Methods

For two of the three brothers, clinical images were taken in 2016, 2 years prior to death. Immunohistochemistry, on both flat-mounts and cross sections, histology, and transmission electron microscopy were used to compare the choroid and retina in GA eyes to those of age-matched controls.

Results

Ulex europaeus agglutinin (UEA) lectin staining of the choroid demonstrated a significant reduction in the percent vascular area and vessel diameter. In one donor, histopathologic analysis demonstrated two separate areas with choroidal neovascularization (CNV). Reevaluation of swept-source optical coherence tomography angiography (SS-OCTA) images revealed CNV in two of the brothers. UEA lectin also revealed a significant reduction in retinal vasculature in the atrophic area. A subretinal glial membrane, composed of processes positive for glial fibrillary acidic protein and/or vimentin, occupied areas identical to those of retinal pigment epithelium (RPE) and choroidal atrophy in all three AMD donors. SS-OCTA also demonstrated presumed calcific drusen in the two donors imaged in 2016. Immunohistochemical analysis and alizarin red S staining verified calcium within drusen, which was ensheathed by glial processes.

Conclusions

This study demonstrates the importance of clinicohistopathologic correlation studies. It emphasizes the need to better understand how the symbiotic relationship between choriocapillaris and RPE, glial response, and calcified drusen impact GA progression.

Long-Term Visual Outcomes in Neovascular Age-Related Macular Degeneration Eyes With Baseline Macular Atrophy on Anti-Vascular Endothelial Growth Factor Treatment

BACKGROUND AND OBJECTIVE

This study explores the connection between macular atrophy (MA) status at baseline and best visual acuity (BVA) after 5 to 7 years of anti-vascular endothelial growth factor (anti-VEGF) injections on eyes with neovascular age-related macular degeneration (nAMD).

PATIENTS AND METHODS

This retrospective study included patients with neovascular age-related macular degeneration receiving anti-VEGF injections at least twice-yearly for 5+ years at Cole Eye Institute. Analyses of variance and linear regressions explored the connection between MA status, baseline MA intensity, and 5-year BVA change.

RESULTS

Of 223 included patients, 5-year BVA change was not statistically significant between MA status groups or from baseline. The population's average 7-year BVA change was -6.3 Early Treatment Diabetic Retinopathy Study letters. Type and frequency of anti-VEGF injections were comparable between MA status groups (P > .05).

CONCLUSION

Regardless of MA status, 5- and 7-year BVA change lacked clinical relevance. If receiving regular treatment for 5+ years, patients with baseline MA achieve comparable visual outcomes to those without MA, with similar treatment and visit burdens. [Ophthalmic Surg Lasers Imaging Retina 2023;54(X):X-X.].

Oxidative stress and epigenetics in ocular vascular aging: an updated review

Vascular aging is an inevitable process with advancing age, which plays a crucial role in the pathogenesis of cardiovascular and microvascular diseases. Diabetic retinopathy (DR) and age-related macular degeneration (AMD), characterized by microvascular dysfunction, are the common causes of irreversible blindness worldwide, however there is still a lack of effective therapeutic strategies for rescuing the visual function. In order to develop novel treatments, it is essential to illuminate the pathological mechanisms underlying the vascular aging during DR and AMD progression. In this review, we have summarized the recent discoveries of the effects of oxidative stress and epigenetics on microvascular degeneration, which could provide potential therapeutic targets for DR and AMD.

Transcriptome Analysis of Retinal and Choroidal Pathologies in Aged BALB/c Mice Following Systemic Neonatal Murine Cytomegalovirus Infection

Our previous studies have shown that systemic neonatal murine cytomegalovirus (MCMV) infection of BALB/c mice spread to the eye with subsequent establishment of latency in choroid/RPE. In this study, RNA sequencing (RNA-Seq) analysis was used to determine the molecular genetic changes and pathways affected by ocular MCMV latency. MCMV (50 pfu per mouse) or medium as control were injected intra-peritoneally (i.p.) into BALB/c mice at <3 days after birth. At 18 months post injection, the mice were euthanized, and the eyes were collected and prepared for RNA-Seq. Compared to three uninfected control eyes, we identified 321 differentially expressed genes (DEGs) in six infected eyes. Using the QIAGEN Ingenuity Pathway Analysis (QIAGEN IPA), we identified 17 affected canonical pathways, 10 of which function in neuroretinal signaling, with the majority of DEGs being downregulated, while 7 pathways function in upregulated immune/inflammatory responses. Retinal and epithelial cell death pathways involving both apoptosis and necroptosis were also activated. MCMV ocular latency is associated with upregulation of immune and inflammatory responses and downregulation of multiple neuroretinal signaling pathways. Cell death signaling pathways are also activated and contribute to the degeneration of photoreceptors, RPE, and choroidal capillaries.

The Fovea-Protective Impact of Double-Layer Sign in Eyes With Foveal-Sparing Geographic Atrophy and Age-Related Macular Degeneration

Purpose

The purpose of this study was to investigate the impact of double-layer sign (DLS) on geographic atrophy (GA) progression in eyes with foveal-sparing GA and age-related macular degeneration (AMD).

Methods

This is a retrospective, consecutive case series of eyes with foveal-sparing GA secondary to AMD with more than 6 months of follow-up. The size of the foveal-sparing area was measured on the fundus autofluorescence images at the first and last visits. Each eye was evaluated for the presence or absence of DLS inside the foveal-sparing area. We graded eyes based on the presence of DLS within the foveal-sparing area and compared the progression of GA between two groups (DLS (+) versus DLS (-)).

Results

We identified 25 eyes with foveal-sparing GA with at least 2 follow-up visits (average interval = 22.7 ± 11.8 months between visits). The mean foveal sparing area was 1.74 ± 0.87 mm2 (range = 0.42-4.14 mm2) at baseline and 1.26 ± 0.75 mm2 (range = 0.25-2.92 mm2) at the last visit. Seventeen eyes (65.3%) were graded as DLS (+) within the foveal-sparing area. Square root progression of GA toward the fovea was significantly faster in the DLS (-) eyes (0.149 ± 0.078 mm/year) compared to the DLS (+) group (0.088 ± 0.052 mm/year; P = 0.04).

Conclusions

The DLS (-) group showed significantly faster centripetal GA progression than the DLS (+) group. Our data suggest that the presence of DLS in the spared foveal area could be a protective factor against foveal progression of GA in eyes with AMD.

The Role of Medical Image Modalities and AI in the Early Detection, Diagnosis and Grading of Retinal Diseases: A Survey

Traditional dilated ophthalmoscopy can reveal diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), diabetic macular edema (DME), retinal tear, epiretinal membrane, macular hole, retinal detachment, retinitis pigmentosa, retinal vein occlusion (RVO), and retinal artery occlusion (RAO). Among these diseases, AMD and DR are the major causes of progressive vision loss, while the latter is recognized as a world-wide epidemic. Advances in retinal imaging have improved the diagnosis and management of DR and AMD. In this review article, we focus on the variable imaging modalities for accurate diagnosis, early detection, and staging of both AMD and DR. In addition, the role of artificial intelligence (AI) in providing automated detection, diagnosis, and staging of these diseases will be surveyed. Furthermore, current works are summarized and discussed. Finally, projected future trends are outlined. The work done on this survey indicates the effective role of AI in the early detection, diagnosis, and staging of DR and/or AMD. In the future, more AI solutions will be presented that hold promise for clinical applications.

Recombinant human klotho protects against hydrogen peroxide-mediated injury in human retinal pigment epithelial cells via the PI3K/Akt-Nrf2/HO-1 signaling pathway

Globally, age-related macular degeneration (AMD) is a common irreversible ophthalmopathy. Oxidative stress of retinal pigment epithelial cells is involved in AMD occurrence and development. Klotho is an anti-aging protein with antioxidant properties. We investigated the protective properties of Klotho on hydrogen peroxide (H₂O₂)-induced injury of retinal pigment epithelial cells (ARPE-19 cells) and its associated pathomechanisms. We found that Klotho pretreatment for 24 h could up-regulate Bcl-2 levels, decrease the cleaved-caspase-3 and Bax levels, inhibit H₂O₂-induced ARPE-19 cell apoptosis, and promote cell proliferation. Klotho pretreatment inhibited the H₂O₂-mediated elevations of reactive oxygen species (ROS) in ARPE-19 cells. It enhanced antioxidant activities of the cells and restored the glutathione peroxidase (GPX), superoxide dismutase (SOD2), catalase (CAT), as well as malondialdehyde (MDA) levels to close to the normal level. N-acetylcysteine (NAC), a reactive oxygen scavenger, could reverse the harmful effects of H₂O₂ on proliferation, apoptosis, and oxidative stress of ARPE-19 cells. Further, Klotho pretreatment enhanced Akt phosphorylation and expression as well as nuclear translocation of Nrf2 in H₂O₂-treated ARPE-19 cells. This indicates that Klotho protects cells from oxidative stress by activating phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)-nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway. Klotho is, therefore, a potential preventive or treatment option for AMD.

Comparison between sodium iodate and lipid peroxide murine models of age-related macular degeneration for drug evaluation-a narrative review

Objective

In this review, non-transgenic models of age-related macular degeneration (AMD) are discussed, with focuses on murine retinal degeneration induced by sodium iodate and lipid peroxide (HpODE) as preclinical study platforms.

Background

AMD is the most common cause of vision loss in a world with an increasingly aging population. The major phenotypes of early and intermediate AMD are increased drusen and autofluorescence, Müller glia activation, infiltrated subretinal microglia and inward moving retinal pigment epithelium cells. Intermediate AMD may progress to advanced AMD, characterized by geography atrophy and/or choroidal neovascularization. Various transgenic and non-transgenic animal models related to retinal degeneration have been generated to investigate AMD pathogenesis and pathobiology, and have been widely used as potential therapeutic evaluation platforms.

Methods

Two retinal degeneration murine models induced by sodium iodate and HpODE are described. Distinct pathological features and procedures of these two models are compared. In addition, practical protocol and material preparation and assessment methods are elaborated.

Conclusion

Retina degeneration induced by sodium iodate and HpODE in mouse eye resembles many clinical aspects of human AMD and complimentary to the existent other animal models. However, standardization of procedure and assessment protocols is needed for preclinical studies. Further studies of HpODE on different routes, doses and species will be valuable for the future extensive use. Despite many merits of murine studies, differences between murine and human should be always considered.

Discovering the Potential of Natural Antioxidants in Age-Related Macular Degeneration: A Review

Age-related macular degeneration (AMD) is a multifactorial disease associated with anatomical changes in the inner retina. Despite tremendous advances in clinical care, there is currently no cure for AMD. This review aims to evaluate the published literature on the therapeutic roles of natural antioxidants in AMD. A literature search of PubMed, Web of Science and Google Scholar for peer-reviewed articles published between 1 January 2011 and 31 October 2021 was undertaken. A total of 82 preclinical and 18 clinical studies were eligible for inclusion in this review. We identified active compounds, carotenoids, extracts and polysaccharides, flavonoids, formulations, vitamins and whole foods with potential therapeutic roles in AMD. We evaluated the integral cellular signaling pathways including the activation of antioxidant pathways and angiogenesis pathways orchestrating their mode of action. In conclusion, we examined the therapeutic roles of natural antioxidants in AMD which warrant further study for application in clinical practice. Our current understanding is that natural antioxidants have the potential to improve or halt the progression of AMD, and tailoring therapeutics to the specific disease stages may be the key to preventing irreversible vision loss.

Progression of macular atrophy in patients undergoing anti-vascular endothelial growth factor therapy for neovascular age-related macular degeneration

PURPOSE

To assess differences in the progression of macular atrophy (MA) between neovascular age-related macular degeneration (AMD) subtypes and to identify the risk factors associated with the foveal involvement among patients with MA undergoing long-term anti-vascular endothelial growth factor (VEGF) treatment.

METHODS

Eighty eyes of 80 patients with neovascular AMD who developed incident MA following anti-VEGF therapy were retrospectively included. Macular atrophy (MA) was quantified using autofluoresence (AF) images within 24 months after the onset of MA, and the enlargement rate was compared between neovascular AMD subtypes. Regression models were constructed to explore relationships between foveal involvement in MA and baseline characteristics.

RESULTS

The growth rate of MA was 0.18 mm² /year for type 1 neovascularization (NV), 0.24 mm² /year for type 2 NV, and 1.21 mm² /year for type 3 NV; differences between groups were significant (p = 0.022). Multivariate logistic regression analysis revealed that thin subfoveal choroidal thickness (p = 0.028), presence of subretinal drusenoid deposit (p = 0.005), type 2 or 3 NV (p = 0.023), and geographic atrophy in the fellow eye (p = 0.035) were significant risk factors for MA with foveal involvement. The number of injections showed no significant association with the progression or the foveal involvement in MA.

CONCLUSIONS

The progression of MA in patients with neovascular AMD undergoing anti-VEGF treatment differed significantly depending on the subtype of neovascularization. The risk of foveal involvement in MA was associated with the baseline factors or phenotype of neovascular AMD rather than with injection frequency of anti-VEGF.

Characterisation of macular neovascularisation in geographic atrophy

AIM

To characterise macular neovascularisation (MNV) developing in eyes affected by geographic atrophy (GA).

METHODS

In this multicentric longitudinal study involving three retina referral centres, patients previously affected by GA who developed an active MNV were included. Patients were investigated using structural optical coherence tomography (OCT), fundus autofluorescence, OCT-angiography and dye angiographies. Patients were treated with ProReNata antivascular endothelial growth factor (VEGF) injections and were revaluated after treatment.

RESULTS

Among 512 patients previously diagnosed with GA, 40 eyes of 40 patients (mean age 80.8±7.9 years, mean GA area 8.73±7.39 mm²) presented with treatment-naïve exudative MNV (accounting for an estimated prevalence of 7.81%; 5.49 to 10.13, 95% CIs) and thus were included in the analysis. 67.5% of MNVs were classified as type 2 MNV, 25% as type 1, 2.5% as type 3 and 5% as mixed phenotype. In 92.5% of cases, active MNV in GA showed subretinal hyperreflective material with or without evidence of subretinal/intraretinal hyporeflective exudation. During a mean follow-up of 28±25 months, patients were treated with 6.6±6.3 anti-VEGF injections, with 2.9±1.4 injections in the first year of treatment. No patient developed GA enlargement in the area of MNV.

CONCLUSIONS

MNVs in GA showed different features and therapeutic response in comparison to previously reported features of MNV in age-related macular degeneration (AMD) without GA. For these reasons, the combined phenotype (ie, GA with neovascular AMD) should be considered as a distinct entity in the research and clinical setting.

Characterizing New-Onset Exudation in the Randomized Phase 2 FILLY Trial of Complement Inhibitor Pegcetacoplan for Geographic Atrophy

OBJECTIVES

To evaluate clinical characteristics of eyes in which investigator-determined new-onset exudative age-related macular degeneration (eAMD) developed during the FILLY trial.

DESIGN

Post hoc analysis of the phase 2 study of intravitreal pegcetacoplan in geographic atrophy (GA).

SUBJECTS

Patients with GA secondary to age-related macular degeneration (AMD), n = 246.

INTERVENTION

Either 15 mg intravitreal pegcetacoplan or sham given monthly or every other month for 12 months followed by a 6-month off-treatment period.

MAIN OUTCOME MEASURES

Time of new eAMD onset in the study eye, history of eAMD in the fellow eye, presence of double-layer sign (DLS) on structural OCT in the study eye, changes in retinal anatomic features by structural OCT and fluorescein angiography (FA), and changes in visual acuity.

RESULTS

Exudation was reported in 26 study eyes across treatment groups over 18 months. Mean time to eAMD diagnosis was 256 days (range, 31-555 days). Overall, a higher proportion of patients with a baseline history of eAMD in the fellow eye (P = 0.016) and a DLS in the study eye (P = 0.0001) demonstrated eAMD. Among study eyes in which eAMD developed, 18 of 26 (69%) had history of fellow-eye eAMD and 19 of 26 (73.1%) had DLS at baseline, compared with 76 of 217 study eyes (35%; P = 0.0007) and 70 of 215 study eyes (32.5%; P < 0.0001), respectively, in which eAMD did not develop. All 21 patients with structural OCT imaging at the time of eAMD diagnosis demonstrated subretinal fluid, intraretinal cysts, or both consistent with exudation. Among 17 patients who underwent FA at eAMD diagnosis, 10 showed detectable macular neovascularization (MNV), all occult lesions. Development of eAMD did not have an appreciable impact on visual acuity, and all patients responded to anti-vascular endothelial growth factor (VEGF) therapy.

CONCLUSIONS

Intravitreal pegcetacoplan slowed the rate of GA growth and was associated with an unexpected dose-dependent increased incidence of eAMD with no temporal clustering of onset. Exudative AMD seemed to be associated with baseline eAMD in the contralateral eye and a DLS, suggestive of nonexudative MNV, in the study eye. The safety profile of pegcetacoplan was acceptable to proceed to phase 3 studies without adjustments to enrollment criteria.

The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration

The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch's membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.

Evolution of oxidative stress, inflammation and neovascularization in the choroid and retina in a subretinal lipid induced age-related macular degeneration model

Oxidative stress, inflammation and neovascularization are the key pathological events that are implicated in human age-related macular degeneration (AMD). There are a limited number of animal models available for evaluating and developing new therapies. Most models represent late exudative or neovascular AMD (nAMD) but there is a relative paucity of models that mimic early events in AMD. The purpose of this study is to characterize the evolution of oxidative stress, inflammation, retinal degeneration and neovascularization in a rat model of AMD, created by subretinal injection of human lipid hydroperoxide (HpODE) that found in the sub-macular region in aged and AMD patients. Subretinal HpODE induced retinal pigment epithelium (RPE) and retinal degeneration resulting in loss of RPE cells, photoreceptors and retinal thinning. RPE degeneration and atrophy were detected by day 5, followed by neural tissue degeneration at day 12 with robust TUNEL positive cells. Western blot analysis confirmed an increase in pro-apoptotic Bak protein at day 12 in retinal tissues. Oxidative damage biomarkers (4-hydroxynonenal, malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and nitrotyrosine) increased in retinal tissue from days 5-12. Müller glial activation was observed in the HpODE injected area at day 5 followed by its remodeling and migration in the outer retina by day 20. RT-qPCR analysis further indicated upregulation of pro-inflammatory genes (TNF-α, IL-1β and IL-6) both in retinal and RPE/choroidal tissue as early as day 2 and persisted until day 12. Upregulation of oxidative stress markers such as NADPH oxidase (NOX and DOUX family) was detected early in retinal tissue by day 2 followed by its upregulation in choroidal tissue at day 5. Neovascularization was demonstrated from day 12 to day 20 post HpODE injection in choroidal tissue. The results from this study indicate that subretinal HpODE induces advanced AMD phenotypes comprising many aspects of both dry/early and late) and neovascular/late AMD as observed in humans. Within 3 weeks via oxidative damage, upregulation of reactive oxygen species and pro-inflammatory genes, pro-apoptotic Bak and pro-angiogenic VEGF upregulation occurs leading to CNV formation. This experimental model of subretinal HpODE is an appropriate model for the study of AMD and provides an important platform for translational and basic research in developing new therapies particularly for early/dry AMD where currently no viable therapies are available.

Clinical Course of Treated Choroidal Neovascularization in Eyes with Pre-existing Geographic Atrophy: Case Series and Reappraisal of the Literature

Purpose: To report the clinical course of choroidal neovascularization (CNV) treated with anti-vascular endothelial growth factor (VEGF) treatment in eyes with pre-existing geographic atrophy (GA).Material and Methods: Multicenter retrospective series. Electronic medical records, clinical notes, and multimodal retinal imaging of patients attending four tertiary referring centers with a diagnosis of unilateral CNV in the context of a pre-existing diagnosis of GA were included. GA was assessed on multimodal retinal imaging including spectral-domain optical coherence tomography (SD-OCT) scan with simultaneous near-infrared (NIR) reflectance imaging (OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany) which was acquired at baseline and every follow-up visit. GA area was measured in treated eyes and fellow eyes using NIR.Results: Fifty-four eyes from 27 patients (23 females, mean age 80.89 ± 7.5) were included. The mean number of injections in the treated eyes was 5.52 ± 1.9 by month 12. From baseline to month 12, stabilization of best-corrected visual acuity (BCVA) and a significant decrease (P = .002) of central macular thickness (CMT) in the treated eyes were observed; there was a slight worsening of BCVA (-2 ETDRS letters) and a non-significant change (P = .4) of CMT in the fellow eyes. GA significantly increased in both treated and untreated eyes (P < .001 and P < .001, respectively) with a similar absolute increase (+2.68 mm² and +2.59 mm², respectively) and growth rate (0.4 and 0.34, respectively).Conclusions: In our study anti-VEGF treatment for CNV in eyes with pre-existing GA was effective in terms of decrease of exudative changes and stabilization of VA by month 12. A similar growth rate of GA between treated and untreated eyes does not support a causal relationship between anti-VEGF treatment and GA progression in this subset of patients. Further studies with a longer follow-up are mandatory to confirm these results.

An in vitro model of chronic wounding and its implication for age-related macular degeneration

Degeneration of the retinal pigment epithelium (RPE) plays a central role in age-related macular degeneration (AMD). Throughout life, RPE cells are challenged by a variety of cytotoxic stressors, some of which are cumulative with age and may ultimately contribute to drusen and lipofuscin accumulation. Stressors such as these continually damage RPE cells resulting in a state of chronic wounding. Current cell-based platforms that model a state of chronic RPE cell wounding are limited, and the RPE cellular response is not entirely understood. Here, we used the electric cell-substrate impedance sensing (ECIS) system to induce a state of acute or chronic wounding on differentiated human fetal RPE cells to analyze changes in the wound repair response. RPE cells surrounding the lesioned area employ both cell migration and proliferation to repair wounds but fail to reestablish their original cell morphology or density after repetitive wounding. Chronically wounded RPE cells develop phenotypic AMD characteristics such as loss of cuboidal morphology, enlarged size, and multinucleation. Transcriptomic analysis suggests a systemic misregulation of RPE cell functions in bystander cells, which are not directly adjacent to the wound. Genes associated with the major RPE cell functions (LRAT, MITF, RDH11) significantly downregulate after wounding, in addition to differential expression of genes associated with the cell cycle (CDK1, CDC6, CDC20), inflammation (IL-18, CCL2), and apoptosis (FAS). Interestingly, repetitive wounding resulted in prolonged misregulation of genes, including FAS, LRAT, and PEDF. The use of ECIS to induce wounding resulted in an over-representation of AMD-associated genes among those dysregulated genes, particularly genes associated with advanced AMD. This simple system provides a new model for further investigation of RPE cell wound response in AMD pathogenesis.

Chronic Dicer1 deficiency promotes atrophic and neovascular outer retinal pathologies in mice

Degeneration of the retinal pigmented epithelium (RPE) and aberrant blood vessel growth in the eye are advanced-stage processes in blinding diseases such as age-related macular degeneration (AMD), which affect hundreds of millions of people worldwide. Loss of the RNase DICER1, an essential factor in micro-RNA biogenesis, is implicated in RPE atrophy. However, the functional implications of DICER1 loss in choroidal and retinal neovascularization are unknown. Here, we report that two independent hypomorphic mouse strains, as well as a separate model of postnatal RPE-specific DICER1 ablation, all presented with spontaneous RPE degeneration and choroidal and retinal neovascularization. DICER1 hypomorphic mice lacking critical inflammasome components or the innate immune adaptor MyD88 developed less severe RPE atrophy and pathological neovascularization. DICER1 abundance was also reduced in retinas of the JR5558 mouse model of spontaneous choroidal neovascularization. Finally, adenoassociated vector-mediated gene delivery of a truncated DICER1 variant (OptiDicer) reduced spontaneous choroidal neovascularization in JR5558 mice. Collectively, these findings significantly expand the repertoire of DICER1 in preserving retinal homeostasis by preventing both RPE degeneration and pathological neovascularization.

The Diverse Roles of TIMP-3: Insights into Degenerative Diseases of the Senescent Retina and Brain

Tissue inhibitor of metalloproteinase-3 (TIMP-3) is a component of the extracellular environment, where it mediates diverse processes including matrix regulation/turnover, inflammation and angiogenesis. Rare TIMP-3 risk alleles and mutations are directly linked with retinopathies such as age-related macular degeneration (AMD) and Sorsby fundus dystrophy, and potentially, through indirect mechanisms, with Alzheimer's disease. Insights into TIMP-3 activities may be gleaned from studying Sorsby-linked mutations. However, recent findings do not fully support the prevailing hypothesis that a gain of function through the dimerisation of mutated TIMP-3 is responsible for retinopathy. Findings from Alzheimer's patients suggest a hitherto poorly studied relationship between TIMP-3 and the Alzheimer's-linked amyloid-beta (A) proteins that warrant further scrutiny. This may also have implications for understanding AMD as aged/diseased retinae contain high levels of A. Findings from TIMP-3 knockout and mutant knock-in mice have not led to new treatments, particularly as the latter does not satisfactorily recapitulate the Sorsby phenotype. However, recent advances in stem cell and in vitro approaches offer novel insights into understanding TIMP-3 pathology in the retina-brain axis, which has so far not been collectively examined. We propose that TIMP-3 activities could extend beyond its hitherto supposed functions to cause age-related changes and disease in these organs.

Inhibition of AMD-Like Pathology With a Neurotrophic Compound in Aged Rats and 3xTg-AD Mice

Age-associated macular degeneration (AMD), which leads to loss of vision at its end stage, is one of the most common neurodegenerative diseases among the elderly. However, to date, no effective drug therapy is available for the prevention of AMD. Here, we report the occurrence of AMD pathology and its prevention by chronic treatment with the neurotrophic peptidergic compound P021, in aged rats and 3xTg-AD mice. We found photoreceptor degeneration, lipofuscin granules, vacuoles, and atrophy in retinal pigment epithelium (RPE) as well as Bruch’s membrane (BM) thickening; in aged rats, we even found rosette-like structure formation. Microgliosis and astrogliosis were observed in different retinal layers. In addition, we also found that total tau, phosphorylated tau, Aβ/APP, and VEGF were widely distributed in the sub-retina of aged rats and 3xTg mice. Importantly, chronic treatment with P021 for 3 months in rats and for 18 months in 3xTg mice ameliorated the pathological changes above. These findings indicate the therapeutic potential of P021 for prevention and treatment of AMD and retinal changes associated with aging and Alzheimer’s disease.

Complement C3 Inhibitor Pegcetacoplan for Geographic Atrophy Secondary to Age-Related Macular Degeneration: A Randomized Phase 2 Trial

PURPOSE

Geographic atrophy (GA), a late stage of age-related macular degeneration (AMD), is a major cause of blindness. Even while central visual acuity remains relatively well preserved, GA often causes considerable compromise of visual function and quality of life. No treatment currently exists. We evaluated the safety and efficacy of pegcetacoplan, a complement C3 inhibitor, for treatment of GA.

DESIGN

Prospective, multicenter, randomized, sham-controlled phase 2 study.

PARTICIPANTS

Two hundred forty-six patients with GA.

METHODS

Patients with GA were assigned randomly in a 2:2:1:1 ratio to receive intravitreal injections of 15 mg pegcetacoplan monthly or every other month (EOM) or sham intravitreal injections monthly or EOM for 12 months with follow-up at months 15 and 18. Area and growth of GA were measured using fundus autofluorescence imaging.

MAIN OUTCOME MEASURES

The primary efficacy end point was mean change in square root GA lesion area from baseline to month 12. Secondary outcome measures included mean change from baseline in GA lesion area without the square root transformation, distance of GA lesion from the fovea, best-corrected visual acuity (BCVA), low-luminance BCVA, and low-luminance visual acuity deficit. The primary safety end point was the number and severity of treatment-emergent adverse events.

RESULTS

In patients receiving pegcetacoplan monthly or EOM, the GA growth rate was reduced by 29% (95% confidence interval [CI], 9-49; P = 0.008) and 20% (95% CI, 0-40; P = 0.067) compared with the sham treatment group. Post hoc analysis showed that the effect was greater in the second 6 months of treatment, with observed reductions of 45% (P = 0.0004) and 33% (P = 0.009) for pegcetacoplan monthly and EOM, respectively. Two cases of culture-positive endophthalmitis and 1 case of culture-negative endophthalmitis occurred in the pegcetacoplan monthly group. New-onset investigator-determined exudative AMD was reported more frequently in pegcetacoplan-treated eyes (18/86 eyes [20.9%] and 7/79 eyes [8.9%] in monthly and EOM groups, respectively) than in sham-treated eyes (1/81 eyes [1.2%]).

CONCLUSIONS

Local C3 inhibition with pegcetacoplan resulted in statistically significant reductions in the growth of GA compared with sham treatment. Phase 3 studies will define the efficacy and safety profile further.

Silencing fibroblast growth factor 7 inhibits krypton laser-induced choroidal neovascularization in a rat model

Choroidal neovascularization (CNV), a characteristic of age-related macular degeneration, is an underlying cause of severe vision loss among elderly patients. Fibroblast growth factor (FGF) is suggested to exert an important role in the pathogenesis of CNV. However, the molecular mechanisms governing this event are not fully elucidated. Herein, we identified the potential role of FGF7 in CNV. To examine the roles of FGF7 in the progression of CNV, rat CNV models were established and treated with small interfering RNA (siRNA) against FGF7 or FGF7 overexpression, followed by identification of expression of FGF7 in the CNV modeled rats. Next, proliferation and migration, and in vitro tube formation of human umbilical vein endothelial cells, as well as expression of vascular endothelial growth factor (VEGF) and transforming growth factor-beta 2 (TGF-β2) were evaluated. CNV led to upregulated FGF7 expression. Cells in the presence of FGF7 siRNA showed suppressed proliferation, migration, and tube formation, along with downregulated VEGF and TGF-β2 expression. Taken together, functional suppression of FGF7 inhibited the onset of CNV, ultimately highlighting a novel therapeutic target for suppressing CNV progression.

Anatomical and functional changes in neovascular AMD in remission: comparison of fibrocellular and fibrovascular phenotypes

PURPOSE

To investigate the anatomical changes and the macular function in neovascular age-related macular degeneration (AMD) eyes, according to the recognition of either fibrocellular or fibrovascular phenotype.

METHODS

We enrolled eyes with previously treated neovascular AMD in remission (no subretinal haemorrhage, sign of fluid in or under the retina and no treatment for at least 6 months). Subjects underwent multimodal imaging assessment and were tested for macular sensitivity using microperimetry. The study cohort was divided according to the presence of fibrosis on multicolour (MC) images, yielding two distinct phenotypic subgroups: (1) fibrocellular group and (2) fibrovascular group.

RESULTS

Nineteen eyes were classified as fibrocellular on MC images, while 22 eyes as fibrovascular. Mean±SD age was 73.9±11.0 years in the fibrocellular group and 75.9±7.1 years in the fibrovascular group (p=0.221). Best-corrected visual acuity was 0.7±0.5 logarithm of the minimum angle of resolution (LogMAR) in the fibrocellular group and 0.3±0.2 LogMAR in the fibrovascular group (p=0.003). On the optical coherence tomography and fundus autofluorescence evaluation, 17/19 eyes with the fibrocellular phenotype and 8/22 eyes with the fibrovascular phenotype displayed the presence of retinal pigment epithelium (RPE) atrophy (p=0.001). The perfusion density within the neovascular lesion was 28.9%±9.9% in the fibrocellular group and 44.2%±5.9 % in the fibrovascular group (p<0.0001).

CONCLUSION

Neovascular AMD eyes in remission and with evidence of fibrocellular scar are characterised by RPE atrophy and reduced perfusion, which are associated with a higher degree of functional impairment. These findings suggest that maturation of vessels in fibrosis might be a better target in neovascular AMD treatments rather than their abolishment.

Fellow Eye Status Is a Biomarker for the Progression Rate of Geographic Atrophy: A Systematic Review and Meta-analysis

TOPIC

Systematic review and meta-analysis of how fellow eye status predicts the progression rate of geographic atrophy (GA).

CLINICAL RELEVANCE

The status of age-related macular degeneration (AMD) in the fellow eye has been used as an indicator of the GA progression rates in primary eyes, but the reported growth rates vary widely in prior clinical studies.

METHODS

We searched MEDLINE, EMBASE, Cochrane Library, Clinicaltrials.gov, and PubMed up to September 12, 2018, for studies that classified treatment-naive GA patients based on different AMD manifestations in the fellow eyes and that monitored GA progression in the primary eyes. Three fellow eye statuses were analyzed: (1) no GA or choroidal neovascularization (CNV) in the fellow eye, (2) GA in the fellow eye, and (3) CNV in the fellow eye. To account for the patients' different entry times, we introduced a horizontal translation factor to shift each dataset within each group. We determined the translation factor by adjusting it 1 month at a time until the r² in weighted least squares regression (r²_WLS) was maximized for the cumulative linear trend line of all datasets. Heterogeneity and study quality were assessed using the I² statistic and Newcastle-Ottawa scale, respectively. Publication bias was evaluated by funnel plots, the Egger test, and the Begg test.

RESULTS

We included 9 studies with 2134 eyes from 1835 patients. After the introduction of translation factors, the datasets in each fellow eye group fit along a straight line with a high r²_WLS. The GA radius growth rate in fellow eyes with GA (0.179±0.003 mm/year) and fellow eyes with CNV (0.159±0.015 mm/year) was significantly higher than that in fellow eyes without GA or CNV (0.110±0.009 mm/year; P < 0.001 and P = 0.02, respectively). We found no significant difference in the GA radius growth rates between fellow eyes with GA and fellow eyes with CNV (P = 0.42).

CONCLUSIONS

We confirmed that the presence of advanced AMD in the fellow eye, defined as GA or CNV, can serve as a biomarker of the GA enlargement rate in the primary eye. This may assist the design of clinical trials and may shed light on the natural history of GA expansion.

Choriocapillaris changes in dry age-related macular degeneration and geographic atrophy: a review

Age-related macular degeneration (AMD) is a leading cause of central vision loss worldwide. The progression of dry AMD from early to intermediate stages is primarily characterized by increasing drusen formation and adverse impact on outer retinal cells. Late stage AMD consists of either geographic atrophy (GA), the non-exudative (dry) AMD subtype, or choroidal neovascularization, the exudative (wet) AMD subtype. GA is characterized by outer retinal and choroidal atrophy, specifically the photoreceptor layer, RPE, and choriocapillaris. Much remains to be discovered regarding the pathogenesis of AMD progression and subsequent development of GA. As the functionality of all three layers is closely linked, the temporal sequence of events that end up in atrophy is important in the understanding of the pathogenic pathway of the disease. The advent of OCTA, and particularly of swept-source technology, has allowed for depth-resolved imaging of retinal vasculature and the choriocapillaris. With the use of OCTA, recent studies demonstrate that choriocapillaris flow alterations are closely associated with the development and progression of AMD. Such changes may even possibly offer predictive value in determining progression of GA. This article reviews studies demonstrating choriocapillaris changes in dry AMD and summarizes the existing literature on the potential role of the choriocapillaris as a key factor in the pathogenesis of AMD.

Topographic Correspondence of Macular Atrophy With Choroidal Neovascularization in Ranibizumab-treated Eyes of the TREX-AMD Trial

PURPOSE

To quantify the extent of topographic correspondence between baseline (BSL) choroidal neovascularization (CNV) and macular atrophy (MA) at follow-up in eyes with neovascular age-related macular degeneration (NVAMD).

DESIGN

Post hoc analysis of randomized controlled clinical trial data.

METHODS

Sixty treatment-naïve NVAMD patients from the TREX-AMD trial were followed for 18 months. Regions of month 18 macular atrophy (MA) were graded on fundus autofluorescence (FAF) with guidance of spectral-domain optical coherence tomography (SDOCT). CNV lesions were graded manually on fluorescein angiography (FA) with lesion components including classic and occult CNV delineated. FAF and FA images were registered to quantitate area and location of overlap between CNV and MA. Outcome measures included overlap of month 18 MA to BSL CNV subtype and progression of MA from BSL to month 18.

RESULTS

Twenty-six eyes had both MA at month 18 and CNV at BSL. A total of 84.6% of eyes showed evidence of MA and CNV overlap. MA appeared by month 18 in regions corresponding to BSL classic CNV in 36.4% of eyes and occult CNV in 40.9%, and in both regions in 22.7%, with more area of MA (AMA) in regions of occult than classic CNV. MA position at BSL corresponded to BSL classic CNV in 76.9% of eyes and occult CNV in 61.5%, and to both regions in 15.4%, with more AMA in regions of occult than classic CNV. Among eyes with MA and CNV at BSL but with no overlap, 50% progressed to involve regions with BS -CNV. Six eyes had no BSL MA but developed MA at month 18 within regions of BSL CNV.

CONCLUSIONS

In ranibizumab-treated eyes with NVAMD, more MA lesions develop within the region of baseline CNV (type 1, CNV-based MA) than outside (type 2, CNV-independent MA). Baseline-MA also tends to be located within regions of CNV in the pretreatment phase.

Evolving multidimensional pharmacological approaches to CNV therapy in AMD

PURPOSE

The leading cause of severe visual loss world-wide is age-related macular degeneration. Although anti-Vascular Endothelial Growth Factor agents have significantly led to the initial pharmacologic reversal of vision loss in many cases of exudative macular degeneration, there still has been recurrence of choroidal neovascularization, and/or the onset of chorioretinal atrophy with fibrosis.

MATERIALS AND METHODS

In this review we discuss the status of anti- Vascular Endothelial Growth Factor in age-related macular degeneration and describe different studies focused on new potential therapeutic targets beyond anti- Vascular Endothelial Growth Factor.

RESULTS

Further investigations have elicited that Vascular Endothelial Growth Factor is only one of many angiogenic, and pro-inflammatory factors that bring about the growth and leakage of active choroidal neovascularization. Various new multifaceted strategies, including inhibitors to down-stream targets of endothelial cell division, such as TNP-470, may lead to a more permanent inactivation of choroidal neovascularization.

CONCLUSIONS

Based on the accumulated results in the treatment of age-related macular degeneration, it is hoped that the appropriate combination of anti-Vascular Endothelial Growth Factor agents with longer-acting and multidimensional pharmaceuticals, such as Methionine Aminopeptidase-2 inhibitors, will more effectively control choroidal neovascularization, prevent atrophy and fibrosis, and reduce the burden of frequent intraocular injections in age-related macular degeneration.

Optical Coherence Tomography Features Preceding the Onset of Advanced Age-Related Macular Degeneration

Purpose

Age-related macular degeneration (AMD) is a progressive disease with multifactorial etiology. There is a need to identify clinical features that are harbingers of advanced disease. We evaluated morphologic features of the retina and choroid on optical coherence tomography (OCT) to determine if they predict progression to advanced disease.

Methods

Progressors transitioned from early or intermediate AMD to advanced disease (n = 40 eyes), and were matched on baseline AMD grade and follow-up interval to nonprogressors who did not develop advanced AMD (n = 40 eyes). Features of the neurosensory retina, photoreceptors, retinal pigment epithelium (RPE), and choroid were evaluated. Logistic regression was used to evaluate univariate associations between features and progression to overall advanced AMD, geographic atrophy (GA), and neovascular disease (NV). Multivariate associations based on stepwise regression models were also assessed.

Results

Ellipsoid zone disruption was associated with progression to overall advanced AMD and NV (odds ratios [ORs]: 17.9 and 30.6; P < 0.001), with a similar trend observed for GA. Drusenoid RPE detachment, RPE thickening, and retinal pigmentary hyperreflective material were significantly associated with higher risk of progression to advanced AMD (ORs: 5.0–8.5) and NV (ORs: 10.8–17.2). Pigmentary hyperreflective material was associated with progression to GA (OR: 7.5, P = 0.009). Total retinal thickness, pigmentary hyperreflective material, nascent GA features, and choroidal vessel abnormalities were independently associated with progression to advanced AMD in a multivariate stepwise model.

Conclusions

Abnormalities in the photoreceptors, retinal thickness, RPE, and choroid were associated with higher risk of developing advanced AMD. These findings provide insights into disease progression, and may be helpful to identify earlier endpoints for clinical studies.

Risk of geographic atrophy in age-related macular degeneration patients treated with intravitreal anti-VEGF agents

Anti-vascular endothelial growth factor (VEGF) intravitreal agents are the only successful treatment for wet age-related macular degeneration (AMD). However, there are emerging signals that anti-VEGF treatment can potentially increase development of geographic atrophy (GA). Histopathologic, animal, and clinical studies support this hypothesis although direct proof of a relationship between GA and use of anti-VEGF agents in neovascular AMD is not yet established. This review presents current evidence supporting an association between anti-VEGF therapy and progression of geographic atrophy. The need of exploring alternative methods of treating AMD is indirectly but clearly emphasized.

A Revised Hemodynamic Theory of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) afflicts one out of every 40 individuals worldwide, causing irreversible central blindness in millions. The transformation of various tissue layers within the macula in the retina has led to competing conceptual models of the molecular pathways, cell types, and tissues responsible for the onset and progression of AMD. A model that has persisted for over 6 decades is the hemodynamic, or vascular theory of AMD progression, which states that vascular dysfunction of the choroid underlies AMD pathogenesis. Here, we re-evaluate this hypothesis in light of recent advances on molecular, anatomic, and hemodynamic changes underlying choroidal dysfunction in AMD. We propose an updated, detailed model of hemodynamic dysfunction as a mechanism of AMD development and progression.