Macular Degeneration Epidemiology: Nature-Nurture, Lifestyle Factors, Genetic Risk, and Gene-Environment Interactions - The Weisenfeld Award Lecture

Treatment for dry age-related macular degeneration: where we stand in 2024

PURPOSE OF REVIEW

This review highlights treatment options, both under investigation and currently available, for the treatment of dry age-related macular degeneration (AMD). An update on current clinical studies for dry AMD has been summarized.

RECENT FINDINGS

Advanced dry AMD, characterized by geographic atrophy (GA), is a leading cause of blindness in the developed world, though prior to 2023 there was no approved treatment. There are now two approved treatments in the United States for GA. Additionally, there are several studies and trials to investigate therapeutic potential and effects of therapies for earlier intervention in dry AMD. Approaches to therapy include inhibiting the complement system, utilizing gene therapy, stem cell therapy, laser therapy, and surgical implants.

SUMMARY

While there has been notable prior advancement in the treatment for neovascular or wet AMD, for the first time there are Food and Drug Administration (FDA) approved treatments for GA. Clinical studies have shown promise for additional methods for managing dry AMD both medically and surgically.

Melatonin and Risk of Age-Related Macular Degeneration

Importance

Melatonin has been shown to oppose several processes that are known to mediate age-related macular degeneration (AMD), but whether melatonin can confer benefits against AMD remains unclear.

Objective

To examine the association between melatonin supplementation and the risk of the development or progression of AMD.

Design, Setting, and Participants

This retrospective cohort study accessed data from TriNetX, a national database of deidentified electronic medical records from both inpatient and outpatient health care organizations across the US, between December 4, 2023, and March 19, 2024. Patients aged 50 years or older, 60 years or older, and 70 years or older with no history of AMD (AMD-naive group) and with a history of nonexudative AMD (nonexudative AMD group) were queried for instances of melatonin medication codes between November 14, 2008, and November 14, 2023. Patients were then classified into either a melatonin group or a control group based on the presence of medication codes for melatonin. Propensity score matching (PSM) was performed to match the cohorts based on demographic variables, comorbidities, and nonmelatonin hypnotic medication use.

Exposure

The presence of at least 4 instances of melatonin records that each occurred at least 3 months apart.

Main Outcomes and Measures

After PSM, the melatonin and the control cohorts were compared to evaluate the risk ratios (RRs) and the 95% CIs of having an outcome. For the AMD-naive group, the outcome was defined as a new diagnosis of any AMD, whereas for the nonexudative AMD group, the outcome was progression to exudative AMD.

Results

Among 121 523 patients in the melatonin-naive group aged 50 years or older (4848 in the melatonin cohort [4580 after PSM; mean (SD) age, 68.24 (11.47) years; 2588 female (56.5%)] and 116 675 in the control cohort [4580 after PSM; mean (SD) age, 68.17 (10.63) years; 2681 female (58.5%)]), melatonin use was associated with a reduced risk of developing AMD (RR, 0.42; 95% CI, 0.28-0.62). Among 66 253 patients aged 50 years or older in the nonexudative AMD group (4350 in the melatonin cohort [4064 after PSM; mean (SD) age, 80.21 (8.78) years; 2482 female (61.1%)] and 61 903 in the control cohort [4064 patients after PSM; mean (SD) age, 80.31 (8.03) years; 2531 female (62.3%)]), melatonin was associated with a reduced risk of AMD progression to exudative AMD (RR, 0.44; 95% CI, 0.34-0.56). The results were consistent among subsets of individuals aged 60 years or older (AMD-naive cohort: RR, 0.36 [95% CI, 0.25-0.54]; nonexudative AMD cohort: RR, 0.38 [95% CI, 0.30-0.49]) and 70 years or older (AMD-naive cohort: RR, 0.35 [95% CI, 0.23-0.53]; nonexudative AMD cohort: RR, 0.40 [95% CI, 0.31-0.51]).

Conclusions and Relevance

Melatonin use was associated with a decreased risk of development and progression of AMD. Although lifestyle factors may have influenced this association, these findings provide a rationale for further research on the efficacy of using melatonin as a preventive therapy against AMD.

RPE melanin and its influence on the progression of AMD

OBJECTIVE

The aim of this review article is to summarize the latest findings and current understanding of the origin of melanin in the retinal pigment epithelium (RPE), its function within the RPE, its role in the pathogenesis of age-related macular degeneration (AMD), its effect on retinal development, and its potential therapeutic benefit in the treatment of AMD.

METHODS

A comprehensive search of peer-reviewed journals was conducted using various combinations of key terms such as "melanin," "retinal pigment epithelium" or "RPE," "age-related macular degeneration" or AMD," "lipofuscin," "oxidative stress," and "albinism." Databases searched include PubMed, Scopus, Science Direct, and Google Scholar. 147 papers published between the years of 1957 and 2023 were considered with an emphasis on recent findings.

SUMMARY OF FINDINGS

AMD is thought to result from chronic oxidative stress within the RPE that results in cellular dysfunction, metabolic dysregulation, inflammation, and lipofuscin accumulation. Melanin functions as a photoscreener, free radical scavenger, and metal cation binding reservoir within the RPE. RPE melanin does not regenerate, and it undergoes degradation over time in response to chronic light exposure and oxidative stress. RPE melanin is important for retinal development and RPE function, and in the aging eye, melanin loss is associated with increased lipid peroxidation, inflammation, and the accumulation of toxic oxidized cellular products. Therefore, melanin-based treatments may serve to preserve RPE and retinal function in AMD.

CONCLUSIONS

The pathogenesis of AMD is not fully understood, but RPE dysfunction and melanin loss in response to chronic oxidative stress and inflammation are thought to be primary drivers of the disease. Due to melanin's antioxidative effects, melanin-based nanotechnology represents a promising avenue for the treatment of AMD.

Predictive Performance of an Updated Polygenic Risk Score for Age-Related Macular Degeneration

PURPOSE

A recent genome-wide association study of age-related macular degeneration (AMD) identified new AMD-associated risk variants. These variants now can be incorporated into an updated polygenic risk score (PRS). This study aimed to assess the performance of an updated PRS, PRS2023, in an independent cohort of older individuals with retinal imaging data and to compare performance with an older PRS, PRS2016.

DESIGN

Cross-sectional study.

PARTICIPANTS

A total of 4175 participants of European ancestry, 70 years of age or older, with genotype and retinal imaging data.

METHODS

We used logistic regression models and area under the receiver operating characteristic curve (AUC) to assess the performance of PRS2023 compared with PRS2016. AMD status and severity were graded using color fundus photography.

MAIN OUTCOME MEASURES

Association of PRS2023 and PRS2016 with AMD risk at baseline.

RESULTS

At enrollment among 4175 participants, 2605 participants (62.4%) had no AMD and 853 participants (20.4%), 671 participants (16.1%), and 46 participants (1.1%) had early, intermediate, and late-stage AMD, respectively. More than 27% of the participants with a high PRS2023 (top quartile) had intermediate or late-stage AMD, compared with < 15% for those in the middle 2 quartiles and less than 13% for those in the lowest quartile. Both PRS2023 and PRS2016 were associated significantly with AMD after adjustment for age, sex, smoking status, and lipid levels, with increasing odds ratios (ORs) for worsening AMD grades. PRS2023 outperformed PRS2016 (P = 0.03 for all AMD and P = 0.03 for late AMD, DeLong test comparing AUC). PRS2023 was associated with late-stage AMD with an adjusted OR of 5.05 (95% confidence interval [CI], 3.41-7.47) per standard deviation. The AUC of a model containing conventional or nongenetic risk factors and PRS2023 was 91% (95% CI, 87%-95%) for predicting late-stage AMD, which improved 12% over the model without the PRS (AUC, 79%; P < 0.001 for difference).

CONCLUSIONS

A new PRS, PRS2023, for AMD outperforms a previous PRS and predicts increasing risk for late-stage AMD (with stronger association for more severe imaging-confirmed AMD grades). Our findings have clinical implications for the improved prediction and risk stratification of AMD.

FINANCIAL DISCLOSURE(S)

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

Risk and protection of different rare protein-coding variants of complement component C4A in age-related macular degeneration

Introduction: Age-related macular degeneration (AMD) is the leading cause of central vision loss in the elderly. One-third of the genetic contribution to this disease remains unexplained. Methods: We analyzed targeted sequencing data from two independent cohorts (4,245 cases, 1,668 controls) which included genomic regions of known AMD loci in 49 genes. Results: At a false discovery rate of <0.01, we identified 11 low-frequency AMD variants (minor allele frequency <0.05). Two of those variants were present in the complement C4A gene, including the replacement of the residues that contribute to the Rodgers-1/Chido-1 blood group antigens: [VDLL1207-1210ADLR (V1207A)] with discovery odds ratio (OR) = 1.7 (p = 3.2 × 10-5) which was replicated in the UK Biobank dataset (3,294 cases, 200,086 controls, OR = 1.52, p = 0.037). A novel variant associated with reduced risk for AMD in our discovery cohort was P1120T, one of the four C4A-isotypic residues. Gene-based tests yielded aggregate effects of nonsynonymous variants in 10 genes including C4A, which were associated with increased risk of AMD. In human eye tissues, immunostaining demonstrated C4A protein accumulation in and around endothelial cells of retinal and choroidal vasculature, and total C4 in soft drusen. Conclusion: Our results indicate that C4A protein in the complement activation pathways may play a role in the pathogenesis of AMD.

Family History of Age-Related Macular Degeneration and Genetics Predict Progression to Advanced Age-Related Macular Degeneration Adjusting for Macular Status, Demographic, and Lifestyle Factors

PURPOSE

To determine if a family history of age-related macular degeneration (AMD) and genetic variants identify eyes at higher risk for progression to advanced AMD (AAMD), after controlling for baseline demographics, behavioral factors, and macular status.

DESIGN

Prospective, longitudinal cohort study.

METHODS

Eyes were classified using the Age-Related Eye Disease Study severity scale. Non-genetic and genetic predictors for progression to AAMD, geographic atrophy, and neovascular disease were evaluated. Cox proportional hazards models using the eye as the unit of analysis were used to calculate hazard ratios (HRs), accounting for correlated data. Discrimination between progressing and non-progressing eyes was assessed using C-statistics and net reclassification improvement (NRI).

RESULTS

Among 4910 eyes, 863 progressed to AAMD over 12 years. Baseline AMD severity scale and status of the fellow eye were important predictors; genes provided additional discrimination. A family history of AMD also independently predicted progression after accounting for genetic and other covariates: 1 family member versus none (HR 1.21 [95% confidence interval {CI} 1.02-1.43]; P = 0.03); ≥2 family members versus none (HR 1.55 [95% CI 1.26-1.90]; P < 0.001). A composite risk score calculated using β estimates of both non-genetic and significant genetic factors predicted progression to AAMD (HR 5.57; 90th vs 10th percentile; area under the receiver operating characteristic curve [AUC] = 0.92), providing superior fit compared with other models, including one with only ocular variables (NRI = 0.34; P < 0.001; AUC = 0.87, ΔAUC 0.05 ± 0.005; P < 0.001).

CONCLUSION

Genetic variants and family history provided additional discrimination for predicting progression to AAMD, after accounting for baseline macular status and other covariates.

5α-Hydroxycostic acid inhibits choroidal neovascularization in rats through a dual signalling pathway mediated by VEGF and angiopoietin 2

BACKGROUND

5α-Hydroxycostic acid is a eudemane sesquiterpene that is isolated from the natural plant, Laggera alata. It exerts anti-inflammatory and anti-angiogenic effects on human breast cancer cells, but its role and underlying mechanism in choroidal neovascularization (CNV) are still unclear. We conducted a study to verify that 5α-Hydroxycostic acid can inhibit the formation and leakage of CNV, and describe the possible dual pathway by which it exerts its inhibitory effects in this process.

METHODS

An in vitro model of choroidal neovascularization was established using VEGF164, while a rat model of choroidal neovascularization was established using a 532 nm laser. In both models, the effects of 5α-Hydroxycostic acid in vivo and in vitro were evaluated to determine its inhibitory effect on abnormal cell proliferation, migration and tubule formation, as well as its effect on pathological changes in choroidal tissues and the area of neovascularization leakage in rats. The levels of components in the VEGF/VEGFR and Ang2/Tie2 signaling pathways were measured in tissues and cells.

RESULTS

In vitro experiments have shown that 5α-Hydroxycostic acid can inhibit abnormal cell proliferation, migration and angiogenesis. Additionally, 5α-Hydroxycostic acid enhances cell adhesion by inhibiting the phosphorylation pathways of VEGFR2 and Tie2. In vivo experiments demonstrated that 5α-Hydroxycostic acid has a positive therapeutic effect on choroidal neovascularization in rats. It can effectively reduce vascular leakage, consistent with the results of the cell experiments.

CONCLUSION

5α-Hydroxycostic acid can inhibit choroidal neovascularization by interfering with the VEGF- and Ang2/Tie2-related pathways, and it may be a good candidate drug for treating CNV.

Revisiting Retinal Degeneration Hallmarks: Insights from Molecular Markers and Therapy Perspectives

Visual impairment and blindness are a growing public health problem as they reduce the life quality of millions of people. The management and treatment of these diseases represent scientific and therapeutic challenges because different cellular and molecular actors involved in the pathophysiology are still being identified. Visual system components, particularly retinal cells, are extremely sensitive to genetic or metabolic alterations, and immune responses activated by local insults contribute to biological events, culminating in vision loss and irreversible blindness. Several ocular diseases are linked to retinal cell loss, and some of them, such as retinitis pigmentosa, age-related macular degeneration, glaucoma, and diabetic retinopathy, are characterized by pathophysiological hallmarks that represent possibilities to study and develop novel treatments for retinal cell degeneration. Here, we present a compilation of revisited information on retinal degeneration, including pathophysiological and molecular features and biochemical hallmarks, and possible research directions for novel treatments to assist as a guide for innovative research. The knowledge expansion upon the mechanistic bases of the pathobiology of eye diseases, including information on complex interactions of genetic predisposition, chronic inflammation, and environmental and aging-related factors, will prompt the identification of new therapeutic strategies.

The Role of Inflammation in Age-Related Macular Degeneration-Therapeutic Landscapes in Geographic Atrophy

Age-related macular degeneration (AMD) is the leading cause of vision loss and visual impairment in people over 50 years of age. In the current therapeutic landscape, intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapies have been central to the management of neovascular AMD (also known as wet AMD), whereas treatments for geographic atrophy have lagged behind. Several therapeutic approaches are being developed for geographic atrophy with the goal of either slowing down disease progression or reversing sight loss. Such strategies target the inflammatory pathways, complement cascade, visual cycle or neuroprotective mechanisms to slow down the degeneration. In addition, retinal implants have been tried for vision restoration and stem cell therapies for potentially a dual purpose of slowing down the degeneration and restoring visual function. In particular, therapies focusing on the complement pathway have shown promising results with the FDA approved pegcetacoplan, a complement C3 inhibitor, and avacincaptad pegol, a complement C5 inhibitor. In this review, we discuss the mechanisms of inflammation in AMD and outline the therapeutic landscapes of atrophy AMD. Improved understanding of the various pathway components and their interplay in this complex neuroinflammatory degeneration will guide the development of current and future therapeutic options, such as optogenetic therapy.

Effect of statins on the age of onset of age-related macular degeneration

BACKGROUND

This study evaluated the relationship between statin use and the age of onset of age-related macular degeneration (AMD).

METHODS

Electronic Health Records from 52,840 patients evaluated at University of California Los Angeles (UCLA) Ophthalmology Clinics and 9,977 patients evaluated at University of California San Francisco (UCSF) Ophthalmology Clinics were screened. Survival analysis was performed using Cox proportional hazards regression models and visualized using Kaplan Meier survival curves, with the following covariates-sex, ethnicity, smoking history, fluoxetine use, obesity, diabetes mellitus, and hypertension.

RESULTS

5,498 of 52,840 patients at UCLA were diagnosed with AMD. Statin use was associated with a later AMD onset (HR = 0.8823, p < 0.0001), while female sex (HR = 1.0852, p= 00,035), obesity (HR = 1.4555, p < 0.0001), and fluoxetine (HR = 1.3797, p= 0.0003) were associated with an earlier AMD onset. Non-hispanic black (HR = 0.5687, p < 0.0001) and hispanic ethnicities (HR = 0.8269, p= 0.0028) were associated with a later AMD onset. When stratifying for ethnicity, statins, fluoxetine, sex, and obesity were significant only within non-hispanic white subjects. Statin use was significant among patients with dry AMD (HR = 0.8410, p= 0.0001) but not wet AMD (0.9188, p= 0.0351). In the replication cohort, 526 of 9,977 patients at UCSF had AMD. Associations between statins (HR = 0.7643, p= 0.0033), non-hispanic black ethnicity (HR = 0.5043, p= 0.0035), and obesity (HR = 1.9602, p < 0.0001) on AMD onset were confirmed.

CONCLUSIONS

In both cohorts, statin use and non-hispanic black ethnicity are associated with a later AMD onset, while obesity with an earlier AMD onset.

The value of pre-symptomatic genetic risk assessment for age-related macular degeneration: the Moran AMD Genetic Testing Assessment (MAGENTA) study-a study protocol for a randomized controlled trial

BACKGROUND

Age-related macular degeneration (AMD) is an irreversible blinding eye condition with complex genetic and environmental etiologies. Genetic testing for AMD for previously identified multiple-risk single nucleotide polymorphisms can help determine an individual's future susceptibility. However, such testing has been discouraged until evidence shows that providing such information to symptomatic or pre-symptomatic individuals will alter their disease course. Therefore, we designed this study to investigate whether knowledge of AMD risk could stimulate the adoption of a healthier lifestyle that could lower the incidence of AMD later in life. We hypothesize that pre-symptomatic individuals informed of a high genetic risk of AMD are more likely to make quantifiable, positive lifestyle changes relative to participants informed of lower genetic risk or randomized to deferred disclosure of genetic testing results.

METHODS

The Moran AMD Genetic Testing Assessment (MAGENTA) study is a phase 2, single-center, prospective, double-masked, randomized controlled trial conducted at the John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Participants are randomized by a 3:1 allocation ratio to immediate and deferred disclosure groups and followed for 12 months. Skin, ocular, and serum carotenoid status, as well as nutritional and social surveys, are assessed at study visits. Skin carotenoid assessment is by resonance Raman spectroscopy and reflectance spectroscopy, ocular carotenoids are measured with Heidelberg Spectralis autofluorescence imaging and fluorescence lifetime imaging ophthalmoscopy (FLIO), and serum carotenoids are quantified using high-performance liquid chromatography. The primary outcome evaluates changes in skin carotenoid status in response to genetic risk disclosure. The secondary outcomes examine changes in ocular and serum carotenoid status in response to genetic risk disclosure. Also, we will correlate AMD genetic risk with baseline ocular and systemic carotenoid status and FLIO.

DISCUSSION

MAGENTA will provide much-needed evidence on whether pre-symptomatic testing for AMD risk can lead to quantifiable long-term changes in behavior and lifestyle associated with a lower incidence of AMD later in life. Findings from the MAGENTA trial will facilitate the design of a future larger, longer-term, multicenter phase 3 trial that could feature subgroup analysis, expanded measures of lifestyle modification, and potential active nutritional interventions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05265624 . Registered on March 3, 2022.

Rare Dysfunctional Complement Factor I Genetic Variants and Progression to Advanced Age-Related Macular Degeneration

Purpose

To evaluate associations between rare dysfunctional complement factor I (CFI) genetic variant status and progression to advanced age-related macular degeneration (AAMD), geographic atrophy (GA), and neovascular disease (NV).

Design

Prospective, longitudinal study.

Participants

Patients aged 55 to 80 years at baseline identifying as White with non-AAMD in 1 or both eyes at baseline were included. Follow-up grades were assigned as early, intermediate, or AAMD (GA or NV). CFI variants were categorized using genotyping and sequencing platforms.

Methods

Analyses were performed using the Seddon Longitudinal Cohort Study (N = 2116 subjects, 3901 eyes, and mean follow-up of 8.3 years) and the Age-Related Eye Disease Study (N = 2837 subjects, 5200 eyes, and mean follow-up of 9.2 years). CFI rare variants associated with low serum factor I (FI) protein levels and decreased FI function (type 1), other AMD genetic variants, and demographic, behavioral, and ocular factors were evaluated. Generalized estimating equations methods were used to assess the association between CFI rare variants and progression, independent of other genetic variants and covariates.

Main Outcome Measures

Progression to AAMD, GA, or NV.

Results

In the prospective cohort of 4953 subjects (9101 eyes with non-AAMD at baseline), 1% were type 1 rare CFI carriers. Over 12 years, progression to AAMD was 44% for carriers and 20% for noncarriers (P < 0.001), 30% of carriers versus 10% of noncarriers progressed to GA (P < 0.001), and 18% of carriers compared with 11% of noncarriers progressed to NV (P = 0.049). CFI carriers were more likely to have a family history of AMD (P for trend = 0.035) and a higher baseline AMD grade (P < 0.001). After adjusting for all covariates, CFI carrier status was associated with progression to GA (odds ratio [OR] = 1.91; 95% confidence interval [CI] = 1.03, 3.52) but not NV (OR = 0.96). Higher body mass index was associated with progression among CFI carriers (body mass index ≥ 25 vs. < 25; OR = 5.8; 95% CI 1.5, 22.3) but not for noncarriers (OR = 1.1; 95% CI = 0.9, 1.3), with P_interaction = 0.011.

Conclusions

Results suggest that carriers of rare dysfunctional type 1 CFI variants are at higher risk for progression to AAMD with GA.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Rethinking the potential and necessity of drug delivery systems in neovascular age-related macular degeneration therapy

Age-related macular degeneration (AMD) is the predominant threat to human vision and ultimately results in blindness. With the increase in the aging population, it has become a more crucial issue to human health. AMD is a multifactorial disease with the unique feature of uncontrollable angiogenesis during initiation and progression. Although increasing evidence indicates that AMD is largely hereditary, the predominant efficient treatment is antiangiogenesis, which mainly involves VEGF and HIF-α as therapeutic targets. The repeated administration of this treatment over the long term, generally through intravitreal injection, has called for the introduction of long-term drug delivery systems, which are expected to be achieved by biomaterials. However, the clinical results of the port delivery system indicate that the optimization of medical devices toward prolonging the activities of therapeutic biologics in AMD therapy seems more promising. These results indicate that we should rethink the possibility and potential of biomaterials as drug delivery systems in achieving long-term, sustained inhibition of angiogenesis in AMD therapy. In this review, the etiology, categorization, risk factors, pathogenesis, and current clinical treatments of AMD are briefly introduced. Next, the development status of long-term drug delivery systems is discussed, and the drawbacks and shortages of these systems are emphasized. By comprehensively considering the pathological aspect and the recent application of drug delivery systems in AMD therapy, we hope to find a better solution for the further development of long-term therapeutic strategies for AMD.

Role of m6A methylation in retinal diseases

Retinal diseases remain among the leading causes of visual impairment in developed countries, despite great efforts in prevention and early intervention. Due to the limited efficacy of current retinal therapies, novel therapeutic methods are urgently required. Over the past two decades, advances in next-generation sequencing technology have facilitated research on RNA modifications, which can elucidate the relevance of epigenetic mechanisms to disease. N6-methyladenosine (m6A), formed by methylation of adenosine at the N6-position, is the most widely studied RNA modification and plays an important role in RNA metabolism. It is dynamically regulated by writers (methyltransferases) and erasers (demethylases), and recognized by readers (m6A binding proteins). Although the discovery of m6A methylation can be traced back to the 1970s, its regulatory roles in retinal diseases are rarely appreciated. Here, we provide an overview of m6A methylation, and discuss its effects and possible mechanisms on retinal diseases, including diabetic retinopathy, age-related macular degeneration, retinoblastoma, retinitis pigmentosa, and proliferative vitreoretinopathy. Furthermore, we highlight potential agents targeting m6A methylation for retinal disease treatment and discuss the limitations and challenges of research in the field of m6A methylation.

Identifying Novel Genes and Variants in Immune and Coagulation Pathways Associated with Macular Degeneration

Purpose

To select individuals and families with a low genetic burden for age-related macular degeneration (AMD), to inform the clinical diagnosis of macular disorders, and to find novel genetic variants associated with maculopathies.

Design

Genetic association study based on targeted and whole-exome sequencing.

Participants

A total of 758 subjects (481 individuals with maculopathy and 277 controls), including 316 individuals in 72 families.

Methods

We focused on 150 genes involved in the complement, coagulation, and inflammatory pathways. Single-variant tests were performed on 7755 variants shared among ≥ 5 subjects using logistic regression. Gene-based tests were used to evaluate aggregate effects from rare and low-frequency variants (at minor allele frequency [MAF] ≤ 5% or ≤ 1%) in a gene using burden tests. For families whose affected members had a low burden of genetic risk based on known common and rare variants related to AMD, we searched for rare variants (MAF < 0.001) whose risk alleles occurred in ≥ 80% of affected individuals but not in controls. Immunohistochemistry was performed to determine the protein expression of a novel gene (coagulation factor II thrombin receptor-like 2 [F2RL2]) in retinal tissues.

Main Outcome Measures

Genotypes and phenotypes of macular degeneration.

Results

We confirmed the association of a synonymous variant in complement factor H (Ala473, rs2274700, proxy to intronic rs1410996, r 2  = 1) with maculopathy (odds ratio, 0.64; P = 4.5 × 10-4). Higher AMD polygenic risk scores (PRSs) were associated with intermediate and advanced AMD. Among families with low PRSs and no known rare variants for maculopathy, we identified 2 novel, highly penetrant missense rare variants in ADAM15, A disintegrin and metalloprotease, metallopeptidase domain 15 (p.Arg288Cys) and F2RL2 (p.Leu289Arg). Immunohistochemistry analyses revealed F2RL2 protein expression in cone photoreceptor outer segments and Müller glia cells of human and pig retinas. Coagulation factor II thrombin receptor-like 2 expression appeared increased in fibrotic areas in advanced AMD samples with neovascularization, suggesting that F2RL2 may play a role in the progression to advanced macular disease.

Conclusions

New missense rare variants in the genes ADAM15 and F2RL2 were associated with maculopathies. Results suggest that novel genes related to the coagulation and immune pathways may be involved in the pathogenesis of macular diseases.

Deep ensemble learning for automated non-advanced AMD classification using optimized retinal layer segmentation and SD-OCT scans

BACKGROUND

Accurate retinal layer segmentation in optical coherence tomography (OCT) images is crucial for quantitatively analyzing age-related macular degeneration (AMD) and monitoring its progression. However, previous retinal segmentation models depend on experienced experts and manually annotating retinal layers is time-consuming. On the other hand, accuracy of AMD diagnosis is directly related to the segmentation model's performance. To address these issues, we aimed to improve AMD detection using optimized retinal layer segmentation and deep ensemble learning.

METHOD

We integrated a graph-cut algorithm with a cubic spline to automatically annotate 11 retinal boundaries. The refined images were fed into a deep ensemble mechanism that combined a Bagged Tree and end-to-end deep learning classifiers. We tested the developed deep ensemble model on internal and external datasets.

RESULTS

The total error rates for our segmentation model using the boundary refinement approach was significantly lower than OCT Explorer segmentations (1.7% vs. 7.8%, p-value = 0.03). We utilized the refinement approach to quantify 169 imaging features using Zeiss SD-OCT volume scans. The presence of drusen and thickness of total retina, neurosensory retina, and ellipsoid zone to inner-outer segment (EZ-ISOS) thickness had higher contributions to AMD classification compared to other features. The developed ensemble learning model obtained a higher diagnostic accuracy in a shorter time compared with two human graders. The area under the curve (AUC) for normal vs. early AMD was 99.4%.

CONCLUSION

Testing results showed that the developed framework is repeatable and effective as a potentially valuable tool in retinal imaging research.

Controversies and Disparities in the Management of Age-Related Macular Degeneration

Age-related macular degeneration is a leading cause of blindness in patients aged 50 years and older. Prior to the 21^st century, there were no effective treatments for this devastating disease. However, the last 20 years have heralded the development of treatments for both the nonexudative and exudative forms. The invention of AREDS vitamin supplements and anti-VEGF therapies forever changed the treatment of dry and wet age-related macular degeneration, respectively. The rapid adoption and expansion of these vision preserving treatments has created controversy regarding their cost, burden of administration, development, and use of new technologies, genetic considerations, and observed societal disparities. Many of these controversies and disparities persist today and will require further research to resolve.

Validity and reliability of food frequency questionnaire used in age-related eye disease studies in Turkish adults

The present study aimed to perform the validity and reliability study of the Food Frequency Questionnaire (FFQ) on the frequency of foods rich in antioxidant nutrients and used in Age-Related Eye Diseases (AREDs). In the first interview of the study, the first application of FFQ was carried out, and blank forms of Dietary Records (DRs) were given. For the validity of the FFQ, a total of 12 d (3 days * 4 weeks) of DR were taken. For the reliability of the FFQ, a test-retest application was made with an interval of 4 weeks. The daily intake means of antioxidant nutrients, omega 3 and total antioxidant capacity data obtained from both the FFQ and DR were calculated, and the concordance between the two methods was evaluated with the Pearson Correlation Coefficient (PCC) and Bland-Altman graphs. The present study was carried out at Ege University İzmir/Turkey, Department of Ophthalmology, Retina Unit. The study was conducted with individuals aged ≥50 years who suffered from Age-Related Macular Degeneration (n 100, 72⋅0 ± 8⋅03 years). The values obtained from the test-retest applications for FFQ reliability were the same. The nutrient intake means obtained from the FFQ were similar or significantly higher than DR (P < 0⋅05). In the Bland-Altman graphical approach, the nutrient data were within the limits of agreement, and the PCCs between the two methods were moderately related. Considered together, this FFQ is a suitable tool for determining the dietary intakes of antioxidant nutrients in the Turkish population.

A hypothetical therapeutic effect of light peripheral panretinal photocoagulation in neovascular age-related macular degeneration

Background

Vascular endothelial growth factor (VEGF) is a significant modulator of ocular angiogenesis, including that of neovascular age-related macular degeneration (nAMD). Intravitreal injection of anti-VEGF is the benchmark treatment for most retinal vascular diseases, including nAMD, diabetic maculopathy, and macular edema secondary to retinal venous occlusion. Anti-VEGF treatment is a high-frequency, time-consuming, non-cost-effective therapy, especially in countries and regions with limited resources. This treatment is easily restricted, and in practice, maintaining long-term periodic care is challenging for patients.

Hypothesis

Light peripheral panretinal photocoagulation (PPRP) is applied in a mild form (barely visible mild light gray mark) anterior to the equator so as not to jeopardize the visual field. PPRP lessens the ischemia that causes neovascularization and decreases the metabolic demand in the peripheral retina. PPRP reduces serum angiopoietin-2 and VEGF levels in patients with type 2 diabetes mellitus with proliferative diabetic retinopathy. We propose using light PPRP to suppress VEGF secretion, aiming to attenuate the VEGF drive and halt choroidal neovascular growth in eyes with nAMD. Our regimen is based on two concepts: first, nAMD is a diffuse or generalized disease that affects the posterior segment; and second, PPRP is very effective in regressing diabetic retinopathy. PPRP has reportedly been successful in cases of macular edema (diabetic or following venous occlusion) resistant to VEGF antagonists. Light PPRP may be used as prophylaxis, adjunctive treatment, or monotherapy in nAMD when intravitreal injections of VEGF antagonists are not feasible.

Conclusions

The established light PPRP therapy could be promising as a one-time, cost-effective therapy or prophylaxis in patients with nAMD or at high risk. This proposed modality could be suitable for patients who have injection phobia or prefer a one-time affordable therapy to the long-term monthly visits to retinologists. Future trials are necessary to verify the safety and efficacy of this proposed treatment modality in selected patients with nAMD.

Association of complement C3 inhibitor pegcetacoplan with reduced photoreceptor degeneration beyond areas of geographic atrophy

Preservation of photoreceptors beyond areas of retinal pigment epithelium atrophy is a critical treatment goal in eyes with geographic atrophy (GA) to prevent vision loss. Thus, we assessed the association of treatment with the complement C3 inhibitor pegcetacoplan with optical coherence tomography (OCT)-based photoreceptor laminae thicknesses in this post hoc analysis of the FILLY trial (NCT02503332). Retinal layers in OCT were segmented using a deep-learning-based pipeline and extracted along evenly spaced contour-lines surrounding areas of GA. The primary outcome measure was change from baseline in (standardized) outer nuclear layer (ONL) thickness at the 5.16°-contour-line at month 12. Participants treated with pegcetacoplan monthly had a thicker ONL along the 5.16° contour-line compared to the pooled sham arm (mean difference [95% CI] + 0.29 z-score units [0.16, 0.42], P < 0.001). The same was evident for eyes treated with pegcetacoplan every other month (+ 0.26 z-score units [0.13, 0.4], P < 0.001). Additionally, eyes treated with pegcetacoplan exhibited a thicker photoreceptor inner segment layer along the 5.16°-contour-line at month 12. These findings suggest that pegcetacoplan could slow GA progression and lead to reduced thinning of photoreceptor layers beyond the GA boundary. Future trials in earlier disease stages, i.e., intermediate AMD, aiming to slow photoreceptor degeneration warrant consideration.

Does outer retinal layer thickness correlate with the central visual field indices in early dry age-related macular degeneration?

PURPOSE

Age-related macular degeneration (ARMD) is the leading cause of irreversible blindness worldwide and Nepal is one among them. We aimed to determine the relationship between outer retinal layer thickness parameters with central visual field indices in early dry ARMD cases among Nepalese population.

MATERIALS AND METHODS

The subjects for this descriptive, cross-sectional study comprised 40 patients with early dry ARMD from the ophthalmology department of a tertiary level hospital of Nepal. The retinal layer thickness was measured with spectral-domain optical coherence tomography (SD-OCT), and the visual field indices were assessed using the 10-2 protocol of Humphrey visual field analyzer (HFA). Thus, the retinal layer structures correlated with visual field indices among our population.

RESULTS

Among our early dry ARMD population, the foveal threshold (FT) was found to be significantly correlated with retinal pigment epithelium (RPE) elevation (P < 0.01, r = -0.541), outer segment (OS) length (P = 0.02, r = 0.465), and inner segment ellipsoid (ISe) band disruption (P = 0.01, r = -0.499), but not with presence of hyperreflective foci (P = 0.464), RPE thickness (P = 0.612), and central macular thickness (P = 0.214). However, no significant correlation between mean deviation and pattern standard deviation of visual field with retinal layer thickness parameters was identified.

CONCLUSION

In early dry ARMD, a reduced FT is significantly correlated with the integrity of the ISe band, thinning of OS length, and drusen-associated RPE elevation. The results highlight the utility of both SD-OCT retinal layer measurement and central visual field testing by HFA in ARMD to monitor the progression of the disease.

A Screening Tool for Self-Evaluation of Risk for Age-Related Macular Degeneration: Validation in a Spanish Population

Purpose

The objectives of this study were the creation and validation of a screening tool for age-related macular degeneration (AMD) for routine assessment by primary care physicians, ophthalmologists, other healthcare professionals, and the general population.

Methods

A simple, self-administered questionnaire (Simplified Théa AMD Risk-Assessment Scale [STARS] version 4.0) which included well-established risk factors for AMD, such as family history, smoking, and dietary factors, was administered to patients during ophthalmology visits. A fundus examination was performed to determine presence of large soft drusen, pigmentary abnormalities, or late AMD. Based on data from the questionnaire and the clinical examination, predictive models were developed to estimate probability of the Age-Related Eye Disease Study (AREDS) score (categorized as low risk/high risk). The models were evaluated by area under the receiving operating characteristic curve analysis.

Results

A total of 3854 subjects completed the questionnaire and underwent a fundus examination. Early/intermediate and late AMD were detected in 15.9% and 23.8% of the patients, respectively. A predictive model was developed with training, validation, and test datasets. The model in the test set had an area under the curve of 0.745 (95% confidence interval [CI] = 0.705-0.784), a positive predictive value of 0.500 (95% CI = 0.449-0.557), and a negative predictive value of 0.810 (95% CI = 0.770-0.844).

Conclusions

The STARS questionnaire version 4.0 and the model identify patients at high risk of developing late AMD.

Translational Relevance

The screening instrument described could be useful to evaluate the risk of late AMD in patients >55 years without having an eye examination, which could lead to more timely referrals and encourage lifestyle changes.

Changes in best-corrected visual acuity in patients with dry age-related macular degeneration after stem cell transplantation: systematic review and meta-analysis

Background

Stem cell transplantation may improve visual acuity in patients with dry age-related macular degeneration. Herein, we aimed to summarise the evidence on the risks and benefits of stem cell transplantation for improving visual acuity, including the risk of adverse events.

Methods

Data were obtained from the PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials databases, and each database was interrogated from the date of inception until 19 March 2022. The rates of visual acuity outcomes and adverse events associated with stem cell transplantation were examined. All statistical analyses were conducted using Review Manager 5.4. The study was registered with PROSPERO (CRD 42022322902).

Results

The analysis examined 10 studies (102 patients), including one and three, randomised and non-randomised clinical trials, and one and five, multicentre prospective and prospective clinical trials, respectively. Meta-analysis showed changes in best-corrected visual acuity in the study eyes after stem cell transplantation (6 months: risk ratio [RR] = 17.00, 95% confidence interval [CI] 6.08–47.56, P < 0.00001; 12 months: RR = 11.00, 95% CI 2.36–51.36, P = 0.002). Subgroup analysis showed that different stem cell types achieved better best-corrected visual acuity at post-operative 6 months, compared to that observed at baseline. Four cases of related ocular adverse events and no related systemic adverse events were reported.

Conclusion

This meta-analysis suggests that stem cell transplantation may improve best-corrected visual acuity in dry age-related macular degeneration, based on small sample sizes and fewer randomised controlled trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02931-y.

A Phase I, Single Ascending Dose Study of GEM103 (Recombinant Human Complement Factor H) in Patients with Geographic Atrophy

Purpose

To establish the safety, tolerability, pharmacokinetics, and pharmacodynamics of an intravitreal injection of recombinant human complement factor H (CFH), GEM103, in individuals with genetically defined age-related macular degeneration (AMD) and geographic atrophy (GA).

Design

Phase I single ascending-dose, open-label clinical trial (ClinicalTrials.gov identifier, NCT04246866).

Participants

Twelve individuals 50 years of age or older with a confirmed diagnosis of foveal GA in the study eye.

Methods

Participants were assigned to the increasing dose cohorts and received 1 50-μl intravitreal injection of GEM103 at doses of 50 μg/eye, 100 μg/eye, 250 μg/eye, or 500 μg/eye; dose escalation was dependent on the occurrence of dose-limiting toxicities.

Main Outcome Measures

Safety assessments included ocular and systemic adverse events (AEs), ocular examinations, clinical laboratory and vital signs, and serum antidrug antibody levels. Biomarkers, measured in the aqueous humor (AH), included CFH and complement activation biomarkers factor Ba and complement component 3a.

Results

No dose-limiting toxicities were reported, enabling escalation to the maximum study dose. No anti-GEM103 antidrug antibodies were detected during the study. Four participants experienced AEs; these were nonserious, mild or moderate in severity, and unrelated to GEM103. The AEs in 2 of these participants were related to the intravitreal injection procedure. No clinically significant ophthalmic changes and no ocular inflammation were observed. Visual acuity was maintained and stable throughout the 8-week follow-up period. No choroidal neovascularization occurred. CFH levels increased in a dose-dependent manner after GEM103 administration with supraphysiological levels observed at week 1; levels were more than baseline for 8 weeks or more in all participants receiving single doses of 100 μg or more. Complement activation biomarkers were reduced 7 days after dose administration.

Conclusions

A single intravitreal administration of GEM103 (up to 500 μg/eye) was well tolerated in individuals with GA. Of the few mild or moderate AEs reported, none were determined to be related to GEM103. No intraocular inflammation or choroidal neovascularization developed. CFH levels in AH were increased and stable for 8 weeks, with pharmacodynamic data suggesting that GEM103 restored complement regulation. These results support further development in a repeat-dose trial in patients with GA with AMD.

Extensive macular atrophy with pseudodrusen-like: Case series and review

PURPOSE

To describe the clinical characteristics of two patients affected by extensive macular atrophy with pseudodrusen-like (EMAP).

METHODS

Two patients affected by EMAP underwent multimodal imaging, including fundus autofluorescence and optical coherence tomography.

RESULTS

The patients showed the typical clinical appearance with macular atrophy with larger vertical axis surrounded by pseudodrusen-like deposits involving the midperiphery, associated with paving stone lesions in the retinal periphery.

CONCLUSION

EMAP is a complex condition sharing clinical characteristics of age-related macular degeneration. Further studies are warranted to identify the early biomarker of the disease.

Functional analysis of rare genetic variants in complement factor I in advanced age-related macular degeneration

Factor I (FI) is a serine protease inhibitor of the complement system. Heterozygous rare genetic variants in complement factor I (CFI) are associated with advanced age-related macular degeneration (AMD). The clinical impact of these variants is unknown since a majority have not been functionally characterized and are classified as 'variants of uncertain significance' (VUS). This study assessed the functional significance of VUS in CFI. Our previous cross-sectional study using a serum-based assay demonstrated that CFI variants in advanced AMD can be categorized into three types. Type 1 variants cause a quantitative deficiency of FI. Type 2 variants demonstrate a qualitative deficiency. However, Type 3 variants consist of VUS that are less dysfunctional than Types 1 and 2 but are not as biologically active as wild type (WT). In this study, we employed site-directed mutagenesis followed by expression of the recombinant variant and a comprehensive set of functional assays to characterize nine Type 3 variants that were identified in 37 individuals. Our studies establish that the expression of the recombinant protein compared with WT is reduced for R202I, Q217H, S221Y and G263V. Further, G362A and N536K, albeit expressed normally, have significantly less cofactor activity. These results led to re-categorization of CFI variants R202I, Q217H, S221Y and G263V as Type 1 variants and to reclassification of N536K and G362A as Type 2. The variants K441R, Q462H and I492L showed no functional defect and remained as Type 3. This study highlights the utility of an in-depth biochemical analysis in defining the pathologic and clinical implications of complement variants underlying AMD.

Exudative versus Nonexudative Age-Related Macular Degeneration: Physiopathology and Treatment Options

Age-related macular degeneration (AMD) is an eye disease typically associated with the aging and can be classified into two types—namely, the exudative and the nonexudative AMD. Currently available treatments for exudative AMD use intravitreal injections, which are associated with high risk of infection that can lead to endophthalmitis, while no successful treatments yet exist for the nonexudative form of AMD. In addition to the pharmacologic therapies administered by intravitreal injection already approved by the Food and Drug Administration (FDA) in exudative AMD, there are some laser treatments approved that can be used in combination with the pharmacological therapies. In this review, we discuss the latest developments of treatment options for AMD. Relevant literature available from 1993 was used, which included original articles and reviews available in PubMed database and also information collected from Clinical Trials Gov website using “age-related macular degeneration” and “antiangiogenic therapies” as keywords. The clinical trials search was limited to ongoing trials from 2015 to date.

Age-Related Macular Degeneration: New Insights in Diagnosis, Treatment, and Prevention

Age-related macular degeneration (AMD) is an aging-related ocular disease that can be responsible for severe loss of visual acuity and loss of autonomy in patients [...]

Exploring Consensus on Preventive Measures and Identification of Patients at Risk of Age-Related Macular Degeneration Using the Delphi Process

Background: Early identification of AMD can lead to prompt and more effective treatment, better outcomes, and better final visual acuity; several risk scores have been devised to determine the individual level of risk for developing AMD. Herein, the Delphi method was used to provide recommendations for daily practice regarding preventive measures and follow-up required for subjects at low, moderate, and high risk of AMD evaluated with the Simplified Test AMD Risk-assessment Scale (STARS^®) questionnaire. Methods: A steering committee of three experts drafted and refined 25 statements on the approach to be recommended in different clinical situations [general recommendations (n = 2), use of evaluation tools (n = 4), general lifestyle advice (n = 3), and AREDS-based nutritional supplementation (n = 5)] with the help of a group of international experts, all co-authors of this paper. Thirty retinal specialists from Europe and the US were chosen based on relevant publications, clinical expertise, and experience in AMD, who then provided their level of agreement with the statements. Statements for which consensus was not reached were modified and voted upon again. Results: In the first round of voting, consensus was reached for 24 statements. After modification, consensus was then reached for the remaining statement. Conclusion: An interprofessional guideline to support preventive measures in patients at risk of AMD based on STARS^® scoring has been developed to aid clinicians in daily practice, which will help to optimize preventive care of patients at risk of AMD.

Efficacy of Anti-Vascular Endothelial Growth Factor Treatment in Neovascular Age-Related Macular Degeneration and Systemic Cardiovascular Risk Factors

This study evaluates whether the presence of cardiovascular risk factors (CRFs) affects functional and morphological responses to anti–vascular endothelial growth factor (VEGF) therapy in patients with neovascular age-related macular degeneration (nAMD). Retrospective analysis included 98 treatment-naïve eyes followed for at least 12 months. Patients received intravitreal injections of ranibizumab or aflibercept with the dosage and regimen set according to each manufacturer’s recommendations for their product. Parameters evaluated at each follow-up visit included best-corrected visual acuity and central retinal thickness. Additionally, the presence of the following CRFs was evaluated: male sex, age of older than 70 years, history of current or past smoking, systemic arterial hypertension, diabetes mellitus, total hypercholesterolemia, low-density lipoprotein hypercholesterolemia, high-density lipoprotein concentration of 45 mg/dL or less, atherogenic dyslipidemia, family history of cardiovascular disease, and chronic kidney disease. A statistically significant better letter gain in visual acuity (p = 0.012) and greater percentage of responders (p = 0.035)—that is patients in whom best corrected visual acuity was stabilized or improved at 12 months—were noted among patients without a diagnosis of arterial hypertension. A statistically significant better mean visual improvement was also achieved in patients with higher total cholesterol plasma levels (p = 0.004), but this finding was not reflected in the significantly higher percentage of responders. The presence of remaining analyzed risk factors did not substantially affect the results of treatment. Systemic arterial hypertension is an independent factor leading to a poor functional outcome following anti-VEGF therapy in patients with nAMD. Effects of anti-VEGF treatment in patients with high total cholesterol levels should be analyzed in further research.

Inhibition of APE1/Ref-1 for Neovascular Eye Diseases: From Biology to Therapy

Proliferative diabetic retinopathy (PDR), neovascular age-related macular degeneration (nvAMD), retinopathy of prematurity (ROP) and other eye diseases are characterized by retinal and/or choroidal neovascularization, ultimately causing vision loss in millions of people worldwide. nvAMD and PDR are associated with aging and the number of those affected is expected to increase as the global median age and life expectancy continue to rise. With this increase in prevalence, the development of novel, orally bioavailable therapies for neovascular eye diseases that target multiple pathways is critical, since current anti-vascular endothelial growth factor (VEGF) treatments, delivered by intravitreal injection, are accompanied with tachyphylaxis, a high treatment burden and risk of complications. One potential target is apurinic/apyrimidinic endonuclease 1/reduction-oxidation factor 1 (APE1/Ref-1). The multifunctional protein APE1/Ref-1 may be targeted via inhibitors of its redox-regulating transcription factor activation activity to modulate angiogenesis, inflammation, oxidative stress response and cell cycle in neovascular eye disease; these inhibitors also have neuroprotective effects in other tissues. An APE1/Ref-1 small molecule inhibitor is already in clinical trials for cancer, PDR and diabetic macular edema. Efforts to develop further inhibitors are underway. APE1/Ref-1 is a novel candidate for therapeutically targeting neovascular eye diseases and alleviating the burden associated with anti-VEGF intravitreal injections.

The rare C9 P167S risk variant for age-related macular degeneration increases polymerization of the terminal component of the complement cascade

Age-related macular degeneration (AMD) is a complex neurodegenerative eye disease with behavioral and genetic etiology and is the leading cause of irreversible vision loss among elderly Caucasians. Functionally significant genetic variants in the alternative pathway of complement have been strongly linked to disease. More recently, a rare variant in the terminal pathway of complement has been associated with increased risk, Complement component 9 (C9) P167S. To assess the functional consequence of this variant, C9 levels were measured in two independent cohorts of AMD patients. In both cohorts, it was demonstrated that the P167S variant was associated with low C9 plasma levels. Further analysis showed that patients with advanced AMD had elevated sC5b-9 compared to those with non-advanced AMD, although this was not associated with the P167S polymorphism. Electron microscopy of membrane attack complexes (MACs) generated using recombinantly produced wild type or P167S C9 demonstrated identical MAC ring structures. In functional assays, the P167S variant displayed a higher propensity to polymerize and a small increase in its ability to induce hemolysis of sheep erythrocytes when added to C9-depleted serum. The demonstration that this C9 P167S AMD risk polymorphism displays increased polymerization and functional activity provides a rationale for the gene therapy trials of sCD59 to inhibit the terminal pathway of complement in AMD that are underway.

Detecting retinal cell stress and apoptosis with DARC: Progression from lab to clinic

DARC (Detection of Apoptosing Retinal Cells) is a retinal imaging technology that has been developed within the last 2 decades from basic laboratory science to Phase 2 clinical trials. It uses ANX776 (fluorescently labelled Annexin A5) to identify stressed and apoptotic cells in the living eye. During its development, DARC has undergone biochemistry optimisation, scale-up and GMP manufacture and extensive preclinical evaluation. Initially tested in preclinical glaucoma and optic neuropathy models, it has also been investigated in Alzheimer, Parkinson's and Diabetic models, and used to assess efficacy of therapies. Progression to clinical trials has not been speedy. Intravenous ANX776 has to date been found to be safe and well-tolerated in 129 patients, including 16 from Phase 1 and 113 from Phase 2. Results on glaucoma and AMD patients have been recently published, and suggest DARC with an AI-aided algorithm can be used to predict disease activity. New analyses of DARC in GA prediction are reported here. Although further studies are needed to validate these findings, it appears there is potential of the technology to be used as a biomarker. Much larger clinical studies will be needed before it can be considered as a diagnostic, although the relatively non-invasive nature of the nasal as opposed to intravenous administration would widen its acceptability in the future as a screening tool. This review describes DARC development and its progression into Phase 2 clinical trials from lab-based research. It discusses hypotheses, potential challenges, and regulatory hurdles in translating technology.

Age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in the industrialized world. AMD is characterized by accumulation of extracellular deposits, namely drusen, along with progressive degeneration of photoreceptors and adjacent tissues. AMD is a multifactorial disease encompassing a complex interplay between ageing, environmental risk factors and genetic susceptibility. Chronic inflammation, lipid deposition, oxidative stress and impaired extracellular matrix maintenance are strongly implicated in AMD pathogenesis. However, the exact interactions of pathophysiological events that culminate in drusen formation and the associated degeneration processes remain to be elucidated. Despite tremendous advances in clinical care and in unravelling pathophysiological mechanisms, the unmet medical need related to AMD remains substantial. Although there have been major breakthroughs in the treatment of exudative AMD, no efficacious treatment is yet available to prevent progressive irreversible photoreceptor degeneration, which leads to central vision loss. Compelling progress in high-resolution retinal imaging has enabled refined phenotyping of AMD in vivo. These insights, in combination with clinicopathological and genetic correlations, have underscored the heterogeneity of AMD. Hence, our current understanding promotes the view that AMD represents a disease spectrum comprising distinct phenotypes with different mechanisms of pathogenesis. Hence, tailoring therapeutics to specific phenotypes and stages may, in the future, be the key to preventing irreversible vision loss.

The Relationship between Age-Related Macular Degeneration and Cardiovascular Disease: A Meta-Analysis

Background:

Age-related macular degeneration (AMD) and cardiovascular disease (CVD) share pathogenic mechanisms, and their lead-lag relationship remains unclear. We performed a meta-analysis of data from longitudinal studies to evaluate the interactive association between age-related macular degeneration (AMD) and cardiovascular disease (CVD).

Methods:

A literature search was performed in PubMed, Embase, and Cochrane Library up to Feb 2019. Estimates were pooled by study quality and type of AMD and CVD. Publication bias was assessed by Begg’s test.

Results:

We identified nine studies for the risk of AMD in CVD and ten studies for the risk of CVD in AMD. Overall, evidence for the risk of CVD in AMD patients was most robust. Both early and late AMD preceded CVD, but more solid significance existed in late AMD. Among the types of CVD, stroke was more tightly associated with AMD than coronary heart disease. Publication bias was not significant in either direction.

Conclusion:

AMD is a risk factor for CVD, which is primarily driven by the increased risk of stroke in patients with late AMD. Moreover, these results suggested that AMD treatment and screening for CVD in AMD patients may have unexplored clinical benefits.

Eye Diseases Direct Interest to Complement Pathway and Macrophages as Regulators of Inflammation in COVID-19

ABSTRACT

Many of the risk factors for developing severe coronavirus disease 2019 (COVID-19) are also risk factors for eye diseases such as age-related macular degeneration (AMD). During the past decades, macrophages and the complement pathway (as a part of the innate immune system) have been identified as important contributors to the development of AMD, and we suggest that these mechanisms are of similar importance for the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Based on the experience with AMD, we discuss how behavioral factors such as diet, smoking and higher body mass index, as well as genetic determinants such as the complement and immune pathway genes may lead to the overactive inflammatory phenotypes seen in some patients with COVID-19, and may in part explain the heterogeneity of disease manifestations and outcomes. Based on this experience, we discuss potential genetic research projects and elaborate on preventive and treatment approaches related to COVID-19.

Rare and Common Genetic Variants, Smoking, and Body Mass Index: Progression and Earlier Age of Developing Advanced Age-Related Macular Degeneration

Purpose

To determine behavioral and genetic factors associated with incidence and age of progression to advanced age-related macular degeneration (AMD), geographic atrophy (GA), and neovascular disease (NV), and to quantify these effects.

Methods

Longitudinal analyses were conducted among 5421 eyes with nonadvanced AMD at baseline in 2976 participants in the Age-Related Eye Disease Study (mean age of 68.8 (±5.0), 56.1% female). Progression was confirmed based on two consecutive visits on the AMD severity scale. Separate analyses for progression and age of progression were performed. All analyses adjusted for correlation between eyes, demographic and behavioral covariates, baseline severity scale, and genetic variants.

Results

A higher genetic risk score (GRS) including eight genetic variants was associated with a higher rate of progression to advanced AMD within each baseline severity scale, especially for the highest risk intermediate level AMD category, and smoking further increased this risk. When assessing age when progression to advanced disease occurred, smoking reduced age of onset by 3.9 years (P < 0.001), and higher body mass index (BMI) led to earlier onset by 1.7 years (P = 0.003), with similar results for GA and NV. Genetic variants associated with earlier age of progression were CFH R1201C (4.3 years), C3 K155Q (2.15 years), and ARMS2/HTRA1 (0.8 years per allele).

Conclusions

Rare variants in the complement pathway and a common risk allele in ARMS2/HTRA1, smoking, and higher BMI can lead to as much as 11.5 additional years of disease and treatment burden. Closer adherence to healthy lifestyles could reduce years of visual impairment.

Functional Analysis of Rare Genetic Variants in Complement Factor I (CFI) using a Serum-Based Assay in Advanced Age-related Macular Degeneration

Purpose

Factor I (FI) is a serine protease regulator of the complement system. Genetic variants in CFI are associated with advanced age-related macular degeneration (AAMD). However, the clinical and functional impact of these variants is unknown. This study assessed the functional significance of rare CFI variants using a serum-based assay.

Methods

Carriers of rare variants with (n = 78) and without AAMD (n = 28), and noncarriers with (n = 49) and without AMD (n = 44) were evaluated. Function of FI was determined by measuring the proteolytic cleavage of C3b to iC3b, using the cofactor protein, Factor H.

Results

CFI variants were categorized into three groups based on antigenic and functional assessments. Type 1 variants (n = 18) in 35 patients with AAMD demonstrated low serum FI levels and a corresponding decrease in FI function. Type 2 variants (n = 6) in 7 individuals demonstrated normal serum FI antigenic levels but reduced degradation of C3b to iC3b. Type 3 variants (n = 15) in 64 individuals demonstrated normal antigenic levels and degradation of C3b to iC3b. However, iC3b generation was low when measured per unit of FI. Thus most rare CFI variants demonstrate either low antigenic levels (type 1) or normal levels but reduced function (types 2 or 3).

Conclusions

Results provide for the first time a comprehensive functional assessment in serum of CFI rare genetic variants and further establish FI's key role in the pathogenesis of AAMD.

Translational Relevance

Stratifying patients in the clinic with a rare CFI variant will facilitate screening and targeting patients most likely to benefit from complement therapies.

CRISPR/Cas9 mediated mutation of the mtnr1a melatonin receptor gene causes rod photoreceptor degeneration in developing Xenopus tropicalis

Nighttime surges in melatonin levels activate melatonin receptors, which synchronize cellular activities with the natural light/dark cycle. Melatonin receptors are expressed in several cell types in the retina, including the photon-sensitive rods and cones. Previous studies suggest that long-term photoreceptor survival and retinal health is in part reliant on melatonin orchestration of circadian homeostatic activities. This scenario would accordingly envisage that disruption of melatonin receptor signaling is detrimental to photoreceptor health. Using in vivo CRISPR/Cas9 genomic editing, we discovered that a small deletion mutation of the Mel1a melatonin receptor (mtnr1a) gene causes a loss of rod photoreceptors in retinas of developing Xenopus tropicalis heterozygous, but not homozygous mutant tadpoles. Cones were relatively spared from degeneration, and the rod loss phenotype was not obvious after metamorphosis. Localization of Mel1a receptor protein appeared to be about the same in wild type and mutant retinas, suggesting that the mutant protein is expressed at some level in mutant retinal cells. The severe impact on early rod photoreceptor viability may signify a previously underestimated critical role in circadian influences on long-term retinal health and preservation of sight. These data offer evidence that disturbance of homeostatic, circadian signaling, conveyed through a mutated melatonin receptor, is incompatible with rod photoreceptor survival.

Genetic Susceptibility, Diet Quality, and Two-Step Progression in Drusen Size

Purpose

To investigate the relationship of growth in drusen size with genetic susceptibility and adherence to the alternate Mediterranean diet.

Methods

Participants in this analysis had complete ocular, genetic, and dietary data with mean follow-up time of 10.2 years in the Age-Related Eye Disease database. Maximal drusen size was graded on an ordinal scale and two-step progression was determined. A genetic risk score using variants associated with advanced AMD and derived from a stepwise regression model yielded 11 variants in 8 genes. Adherence to the alternate Mediterranean diet was assessed using a nine-component score based on intake of vegetables, fruits, legumes, whole cereals, fish, meat, nuts, alcohol, and monounsaturated-to-saturated fatty acids ratio. Multivariate Cox proportional hazards models were used.

Results

Among 3023 eligible eyes, 19% had drusen growth. In the stepwise selection, common and rare risk alleles for CFH Y402H, CFH rs1410996, CFH R1210C, C3 R102G, C3 K155Q, and ARMS2/HTRA1, as well as VEGF-A, TIMP3, NPLOC4, and HSPH1 variants were significantly associated with 2-step progression in drusen size, and the C2 E318D protective allele conferred decreased risk, adjusting for other covariates. A higher genetic risk score conferred a higher risk (hazard ratio per 1-unit increase, 2.68; 95% confidence interval, 2.23-3.23; P < 0.001), and a medium/high adherence to alternate Mediterranean diet score (4-9) tended to lower risk (hazard ratio, 0.83; 95% confidence interval, 0.68-0.99; P = 0.049), adjusting for all covariates.

Conclusions

Genetic susceptibility was independently related to drusen growth. A Mediterranean-style diet with healthful nutrient-rich foods (fruits, vegetables, legumes and fish), may reduce enlargement of drusen, the hallmark of AMD.

Choriocapillaris dropout in early age-related macular degeneration

Loss of choriocapillaris (CC) in advanced age-related macular degeneration (AMD) is well documented but changes in early AMD have not been quantified. Postmortem eyes from donors with clinically documented early AMD were examined in choroidal whole mounts to determine the area, pattern, and severity of CC loss. Choroids from postmortem human eyes without AMD (n = 7; mean age = 86.1) and from eyes with a Grade 2 clinical classification of early AMD (n = 7; mean age = 87) were immunolabeled with Ulex europaeus agglutinin (UEA) lectin-FITC to stain blood vessels. Whole mounts were imaged using confocal microscopy and image analysis was performed to determine the area of vascular changes and density of vasculature (percent vascular area, %VA). All areas evaluated had a complete RPE monolayer upon gross examination. In age-matched control eyes, the CC had broad lumens and a homogenous pattern of freely interconnecting capillaries. The mean %VA ± standard deviation in submacula of control subjects was 78.1 ± 3.25%. In eyes with early AMD, there was a significant decrease in mean %VA to 60.1 ± 10.4% (p < 0.0001). The paramacular %VA was not significantly different in eyes with or without AMD. The area of submacular choroid affected by CC dropout was 0.04 ± 0.09 mm² in control eyes. In eyes with early AMD, the mean area affected by CC dropout was significantly increased (10.4 ± 6.1 mm²; p < 0.001). In some cases, incipient neovascular buds were observed at the border of regions with CC dropout in early AMD choroids. In conclusion, UEA lectin-labeled choroidal whole mounts from donors with clinically documented early AMD has provided a unique opportunity to examine regional changes in vascular pathology associated with choriocapillaris. The study demonstrated attenuation of submacular CC in early AMD subjects but no vascular pathology was observed outside the submacular region. While the affected area in some eyes was quite extensive histologically, these changes may not be detectable clinically using standard in vivo imaging.

The Interplay between Retinal Pathways of Cholesterol Output and Its Effects on Mouse Retina

In mammalian retina, cholesterol excess is mainly metabolized to oxysterols by cytochromes P450 27A1 (CYP27A1) and 46A1 (CYP46A1) or removed on lipoprotein particles containing apolipoprotein E (APOE). In contrast, esterification by sterol-O-acyltransferase 1 (SOAT) plays only a minor role in this process. Accordingly, retinal cholesterol levels are unchanged in Soat1^-/- mice but are increased in Cyp27a1^-/-Cyp46a1^-/- and Apoe^-/- mice. Herein, we characterized Cyp27a1^-/-Cyp46a1^-/-Soat1^-/- and Cyp27a1^-/-Cyp46a1^-/-Apoe^-/- mice. In the former, retinal cholesterol levels, anatomical gross structure, and vasculature were normal, yet the electroretinographic responses were impaired. Conversely, in Cyp27a1^-/-Cyp46a1^-/-Apoe^-/- mice, retinal cholesterol levels were increased while anatomical structure and vasculature were unaffected with only male mice showing a decrease in electroretinographic responses. Sterol profiling, qRT-PCR, proteomics, and transmission electron microscopy mapped potential compensatory mechanisms in the Cyp27a1^-/-Cyp46a1^-/-Soat1^-/- and Cyp27a1^-/-Cyp46a1^-/-Apoe^-/- retina. These included decreased cholesterol biosynthesis along with enhanced formation of intra- and extracellular vesicles, possibly a reserve mechanism for lowering retinal cholesterol. In addition, there was altered abundance of proteins in Cyp27a1^-/-Cyp46a1^-/-Soat1^-/- mice that can affect photoreceptor function, survival, and retinal energy homeostasis (glucose and fatty acid metabolism). Therefore, the levels of retinal cholesterol do not seem to predict retinal abnormalities, and it is rather the network of compensatory mechanisms that appears to determine retinal phenotype.

Association Between Perifoveal Drusen Burden Determined by OCT and Genetic Risk in Early and Intermediate Age-Related Macular Degeneration

Purpose

The purpose of this study was to determine associations between macular drusen parameters derived from an automatic optical coherence tomography (OCT) algorithm, nonadvanced age-related macular degeneration (AMD) stage, and genetic variants.

Methods

Eyes classified as early or intermediate AMD with OCT imaging and genetic data were selected (n = 239 eyes). Drusen area and volume measurements were estimated using the Zeiss Cirrus advanced retinal pigment epithelium analysis algorithm in a perifoveal zone centered on the fovea. Associations between drusen measurements and common genetic variants in the complement and high-density lipoprotein (HDL) lipid pathways and the ARMS2/HTRA1 variant were calculated using generalized estimating equations and linear mixed models adjusting for age, sex, smoking, body mass index, and education.

Results

Drusen area ≥ the median was independently associated with a higher number of risk alleles for CFH risk score and risk variants in C3 and ARMS2/HTRA1 compared with eyes with no measurable drusen. Similar results were obtained for drusen volume. When all genes were analyzed in the same model, only CFH score and ARMS2/HTRA1 were associated with drusen measurements. HDL pathway genes were not significantly related to drusen parameters. Nonadvanced AMD stages were associated with OCT-derived drusen area and volume.

Conclusions

Variants in CFH and ARMS2/HTRA1, commonly associated with advanced AMD, were independently associated with an increase in drusen burden determined by OCT in an allele dose dependent manner, in eyes with early and intermediate AMD. Biomarkers such as a quantitative classification of nonadvanced AMD and other OCT-derived subphenotypes could provide earlier anatomic endpoints for clinical trials and facilitate the development of new therapies for AMD.

Quantitative choriocapillaris evaluation in intermediate age-related macular degeneration by swept-source optical coherence tomography angiography

PURPOSE

To investigate choriocapillaris (CC) perfusion, by evaluating flow voids (FV), in eyes with intermediate age-related macular degeneration (iAMD) using swept-source optical coherence tomography angiography (SS-OCT-A).

METHODS

Patients with bilateral or unilateral iAMD and normal controls underwent SS-OCT and OCT-A examination. Choriocapillaris (CC) FVs were quantitatively assessed on OCT-A images using matlab (version 2017b; MathWorks, Natick, MA, USA), after a preprocessing aimed at compensating for CC attenuation artefacts. Three different thresholds [1 standard deviation (SD), 1.25 SD and 1.5 SD] were applied. Final FV percentage (FV%) was calculated as the ratio between area with absent flow and total scanned area.

RESULTS

Of 41 patients with iAMD and 16 normal subjects enrolled in the study, 39 eyes (39 patients) with iAMD and all 16 normal eyes (16 control subjects) were included in the final analysis. Mean FV% (1 SD) was 13.45 ± 0.66 in controls, 14.19 ± 1.23 in bilateral iAMD and 14.21 ± 0.99 in unilateral iAMD (p = 0.03, for difference between controls and bilateral iAMD). Mean FV% (1.25 SD) was 6.55 ± 0.65 in controls, 7.33 ± 1.4 in bilateral iAMD and 7.06 ± 1.4 in unilateral iAMD (p = 0.048, for difference between controls and bilateral iAMD). Mean FV% (1.5 SD) was 2.71 ± 0.82 in controls, 2.55 ± 1.12 in bilateral iAMD and 3.25 ± 1.17 in unilateral iAMD (p = 0.038, for difference between bilateral and unilateral iAMD).

CONCLUSION

A significantly higher FV% was found in patients with iAMD versus controls. A higher trend in FV% was found in unilateral iAMD (with neovascular AMD in the fellow eye) versus bilateral iAMD, when applying the lowest threshold. Further, larger and longitudinal studies are needed to confirm this data.

Validated Prediction Models for Macular Degeneration Progression and Predictors of Visual Acuity Loss Identify High-Risk Individuals

PURPOSE

To determine predictive factors and risk scores for conversion to overall advanced age-related macular degeneration (AMD), geographic atrophy (GA), neovascular disease (NV), and loss of vision, and to validate the model for AMD in an external cohort.

METHODS

Progression to advanced AMD was evaluated using stepwise survival analysis. Risk scores including genetic, demographic, behavioral, and ocular factors were derived for 3 AMD endpoints and were validated and calibrated in a large independent cohort. Vision loss of 15 or more letters was evaluated as a new endpoint in genetic analyses.

RESULTS

Eight common and rare variants in genes CFH, C3, ARMS2, COL8A1, and HSPH1/B3GALTL conferred a significantly higher risk of transition to advanced AMD. Three loci (C2, CFB, RAD51B) were associated with lower rate of progression. A protective effect was suggested for CTRB1 and PELI3. The age-adjusted area under the curve (AUC) for the composite model including 13 loci model was 0.900 over 12 years (0.896 in the validation cohort). Generally, progressors had a higher risk category and nonprogressors had a lower risk category when genetic factors were considered. Furthermore, there was heterogeneity between models for GA and NV. The model was calibrated in the validation cohort. Determinants of visual loss included age, education, body mass index, smoking, and several common and rare genetic variants.

CONCLUSION

Eyes with the same baseline macular grade had a wide range of estimated probability of subsequent progression and visual loss based on the validated risk score. Identifying high-risk individuals at an earlier stage using predictive modeling could lead to improved preventive and therapeutic strategies in the era of precision medicine.

Common and rare genetic variants of complement components in human disease

Genetic variability in the complement system and its association with disease has been known for more than 50 years, but only during the last decade have we begun to understand how this complement genetic variability contributes to the development of diseases. A number of reports have described important genotype-phenotype correlations that associate particular diseases with genetic variants altering specific aspects of the activation and regulation of the complement system. The detailed functional characterization of some of these genetic variants provided key insights into the pathogenic mechanisms underlying these pathologies, which is facilitating the design of specific anti-complement therapies. Importantly, these analyses have sometimes revealed unknown features of the complement proteins. As a whole, these advances have delineated the functional implications of genetic variability in the complement system, which supports the implementation of a precision medicine approach based on the complement genetic makeup of the patients. Here we provide an overview of rare complement variants and common polymorphisms associated with disease and discuss what we have learned from them.