Regression of Some High-risk Features of Age-related Macular Degeneration (AMD) in Patients Receiving Intensive Statin Treatment

Drusen in AMD from the Perspective of Cholesterol Metabolism and Hypoxic Response

Drusen are one of the most characteristic pathologies of precursor lesion of age-related macular degeneration (AMD). Drusen comprise a yellowish white substance that accumulates typically under the retinal pigment epithelium (RPE), and their constituents are lipids, complement, amyloid, crystallin, and others. In the past, many researchers have focused on drusen and tried to elucidate the pathophysiology of AMD because they believed that disease progression from early AMD to advanced AMD might be based on drusen or drusen might cause AMD. In fact, it is well established that drusen are the hallmark of precursor lesion of AMD and a major risk factor for AMD progression mainly based on their size and number. However, the existence of advanced AMD without drusen has long been recognized. For example, polypoidal choroidal vasculopathy (PCV), which comprises the majority of AMD cases in Asians, often lacks drusen. Thus, there is the possibility that drusen might be no more than a biomarker of AMD and not a cause of AMD. Now is the time to reconsider the relationship between AMD and drusen. In this review, we focus on early AMD pathogenesis based on basic research from the perspective of cholesterol metabolism and hypoxic response in the retina, and we discuss the role of drusen.

Treatment Strategies for Anti-VEGF Resistance in Neovascular Age-Related Macular Degeneration by Targeting Arteriolar Choroidal Neovascularization

Despite extensive use of intravitreal anti-vascular endothelial growth factor (anti-VEGF) biologics for over a decade, neovascular age-related macular degeneration (nAMD) or choroidal neovascularization (CNV) continues to be a major cause of irreversible vision loss in developed countries. Many nAMD patients demonstrate persistent disease activity or experience declining responses over time despite anti-VEGF treatment. The underlying mechanisms of anti-VEGF resistance are poorly understood, and no effective treatment strategies are available to date. Here we review evidence from animal models and clinical studies that supports the roles of neovascular remodeling and arteriolar CNV formation in anti-VEGF resistance. Cholesterol dysregulation, inflammation, and ensuing macrophage activation are critically involved in arteriolar CNV formation and anti-VEGF resistance. Combination therapy by neutralizing VEGF and enhancing cholesterol removal from macrophages is a promising strategy to combat anti-VEGF resistance in CNV.

The Relationship between Complements and Age-Related Macular Degeneration and Its Pathogenesis

Age-related macular degeneration is a retinal disease that causes permanent loss of central vision in people over the age of 65. Its pathogenesis may be related to mitochondrial dysfunction, inflammation, apoptosis, autophagy, complement, intestinal flora, and lipid disorders. In addition, the patient's genes, age, gender, cardiovascular disease, unhealthy diet, and living habits may also be risk factors for this disease. Complement proteins are widely distributed in serum and tissue fluid. In the early 21st century, a connection was found between the complement cascade and age-related macular degeneration. However, little is known about the effect of complement factors on the pathogenesis of age-related macular degeneration. This article reviews the factors associated with age-related macular degeneration, the relationship between each factor and complement, the related functions, and variants and provides new ideas for the treatment of this disease.

Systemic Dyslipidemia in Age-related Macular Degeneration: An Updated Systematic Review and Meta-analysis

Topic

Though lipid and cholesterol dyshomeostasis is thought to contribute to the pathogenesis of age-related macular degeneration (AMD), there is no consensus regarding which elements of systemic lipid homeostasis are perturbed in AMD. In this systematic review and meta-analysis, an update to that performed by Wang et al in 2016, we characterized serum lipoprotein profiles in patients with AMD and its various stages.

Clinical Relevance

These findings may identify novel therapeutic approaches for AMD, a leading cause of blindness among older adults in the industrialized world.

Methods

We used MEDLINE, Embase, and Web of Science to identify articles from database inception to May 2022 that reported blood/serum levels of lipid subspecies (triglycerides [TGs], total cholesterol [TC], low-density lipoprotein [LDL], and high-density lipoprotein [HDL]) in patients with AMD compared with controls. We meta-analyzed the data by generating multilevel random-effects models using restricted maximum likelihood estimation.

Results

Our updated meta-analysis included 56 studies, almost 3 times as many studies as the 2016 meta-analysis with a total of 308 188 participants. There were no significant differences in serum TG, TC, LDL, or HDL between patients with AMD and non-AMD controls. Given significant heterogeneity, we performed subanalyses specifically in patients with early to intermediate nonexudative AMD, advanced nonexudative AMD, and advanced exudative AMD. Compared with non-AMD controls, patients with early to intermediate nonexudative AMD had significantly lower serum TG (standardized mean difference [SMD]: -0.03; 95% confidence interval [95% CI]: -0.06 to -0.01) and higher serum HDL (SMD: 0.07; 95% CI: 0.04-0.11). Patients with advanced exudative AMD had significantly higher serum LDL (SMD: 0.33; 95% CI: 0.04-0.62) compared with non-AMD controls. There were no other significant differences identified.

Conclusion

We found that there is significant heterogeneity in systemic lipoproteins in patients with AMD compared with non-AMD controls. The specific pattern of lipid dyshomeostasis appeared to be distinct based on AMD stage. These findings highlight both the underlying heterogeneity of AMD as well as the presence of distinct pathophysiological mechanisms involved at different stages or subtypes of AMD and may inform the development of novel therapeutic approaches.

Financial Disclosures

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

The Association between Statins Intake and Risk of Post Stroke Pneumonia: A Systematic Review and Meta-Analysis

AIM

This research aimed to examine the relationship between the intake of statins and the risk of post-stroke pneumonia in a systematic review and meta-analysis study.

METHODS

An extensive search of published articles on March 21st, 2023, was done in several databases, like Web of Science (ISI), PubMed, Cochrane Library, Embase, Scopus, and Google Scholar. The Newcastle Ottawa Scale (NOS) checklist was employed to evaluate the quality of observational studies. Statistical tests (Chi-square test and I2) and graphical techniques (Forest plot) were used to determine whether heterogeneity existed in the meta-analysis studies. Funnel plots and Begg and Egger's tests were used to assess the publication bias.

RESULTS

Seven studies (5 cohort and 2 case-control studies) were retrieved to examine the association between statins and post-stroke pneumonia. The sample size of the studies compiled in the meta- analysis was obtained to be 68,966 participants. Meta-analysis demonstrated that the overall odds of post-stroke pneumonia in the statin group was equal to 0.87 (95% CI: 0.67 - 1.13; p-value 0.458). Subgroup analysis indicated that the odds of post-stroke pneumonia in the statin group was equal to 0.93 (95% CI: 0.73-1.18; p-value = 0.558) in the cohort studies, and equal to 0.92 (95% CI: 0.37-2.26; p-value = 0.857) in the case-control studies. The examination of the association between the intake of statins and post-stroke pneumonia showed no evidence of publication bias (Begg's test, p-value = 0.368; Eggers test, p-value = 0.282).

CONCLUSION

In this study, no relationship has been observed between receiving statins and the risk of post-stroke pneumonia.

Genetic and molecular biomarkers for geographic atrophy

Geographic atrophy (GA) is characterized by atrophy of the retina, retinal pigment epithelium and choriocapillaris, causing a gradual loss of vision over time. Treatment options to prevent initiation or progression of GA are limited; two recently FDA-approved inhibitors of the complement system (pegcetacoplan, avacincaptad pegol) showed a modest decrease in GA lesion growth in phase 3 clinical trials. Exploration of genetic and molecular biomarkers in GA plays a critical role in our battle against this blinding disease to improve early disease detection, to find more effective therapies, and to provide personalized care to patients. In this review, we provide a comprehensive overview of the current literature investigating genetic and molecular biomarkers for GA. Genetic studies identified multiple genes and variants that play a role in progression to GA and GA lesion growth, involving pathways such as complement activation, extracellular matrix interaction and lipid metabolism. The number of published studies assessing molecular biomarkers for GA initiation and progression in ocular matrices is limited. Several studies evaluated molecular biomarkers in the systemic circulation, showing higher levels of complement activation and a causal role of lipid subfractions in GA. Larger, well-powered studies are needed to identify novel and validate existing biomarkers, and to investigate the potential of combining genetic and molecular markers with imaging techniques for more accurate diagnosis and monitoring of GA. The development of personalized medicine approaches based on individual genetic and molecular profiles could hold promise for more effective and targeted treatments for this devastating disease.

Association of lipid-lowering drugs and antidiabetic drugs with age-related macular degeneration: a meta-analysis in Europeans

BACKGROUND/AIMS

To investigate the association of commonly used systemic medications with prevalent age-related macular degeneration (AMD) in the general population.

METHODS

We included 38 694 adults from 14 population-based and hospital-based studies from the European Eye Epidemiology consortium. We examined associations between the use of systemic medications and any prevalent AMD as well as any late AMD using multivariable logistic regression modelling per study and pooled results using random effects meta-analysis.

RESULTS

Between studies, mean age ranged from 61.5±7.1 to 82.6±3.8 years and prevalence ranged from 12.1% to 64.5% and from 0.5% to 35.5% for any and late AMD, respectively. In the meta-analysis of fully adjusted multivariable models, lipid-lowering drugs (LLD) and antidiabetic drugs were associated with lower prevalent any AMD (OR 0.85, 95% CI=0.79 to 0.91 and OR 0.78, 95% CI=0.66 to 0.91). We found no association with late AMD or with any other medication.

CONCLUSION

Our study indicates a potential beneficial effect of LLD and antidiabetic drug use on prevalence of AMD across multiple European cohorts. Our findings support the importance of metabolic processes in the multifactorial aetiology of AMD.

Acetyl-CoA carboxylase Inhibition increases RPE cell fatty acid oxidation and limits apolipoprotein efflux

Purpose

In age-related macular degeneration (AMD) and Sorsby's fundus dystrophy (SFD), lipid-rich deposits known as drusen accumulate under the retinal pigment epithelium (RPE). Drusen may contribute to photoreceptor and RPE degeneration in AMD and SFD. We hypothesize that stimulating β-oxidation in RPE will reduce drusen accumulation. Inhibitors of acetyl-CoA carboxylase (ACC) stimulate β-oxidation and diminish lipid accumulation in fatty liver disease. In this report we test the hypothesis that an ACC inhibitor, Firsocostat, limits the accumulation of lipid deposits in cultured RPE cells.

Methods

We probed metabolism and cellular function in mouse RPE-choroid, human fetal- derived RPE cells, and induced pluripotent stem cell-derived RPE cells. We used 13 C6-glucose and 13 C16-palmitate to determine the effects of Firsocostat on glycolytic, Krebs cycle, and fatty acid metabolism. 13 C labeling of metabolites in these pathways were analyzed using gas chromatography-linked mass spectrometry. We quantified ApoE and VEGF release using enzyme-linked immunosorbent assays. Immunostaining of sectioned RPE was used to visualize ApoE deposits. RPE function was assessed by measuring the trans-epithelial electrical resistance (TEER).

Results

ACC inhibition with Firsocostat increases fatty acid oxidation and remodels lipid composition, glycolytic metabolism, lipoprotein release, and enhances TEER. When human serum is used to induce sub-RPE lipoprotein accumulation, fewer lipoproteins accumulate with Firsocostat. In a culture model of Sorsby's fundus dystrophy, Firsocostat also stimulates fatty acid oxidation, improves morphology, and increases TEER.

Conclusions

Firsocostat remodels intracellular metabolism and improves RPE resilience to serum-induced lipid deposition. This effect of ACC inhibition suggests that it could be an effective strategy for diminishing drusen accumulation in the eyes of patients with AMD.

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.

Causal effects of serum lipid biomarkers on early age-related macular degeneration using Mendelian randomization

BACKGROUND

Age-related macular degeneration (AMD) is one of the major causes of vision loss. Early AMD needs to be taken seriously, but the causal effects of lipid biomarkers on early AMD remain unclear.

METHODS

In this study, two-sample Mendelian randomization (MR) analysis was performed to systematically assess the causal relationships between seven serum lipid biomarkers (apolipoprotein A (ApoA), apolipoprotein B (ApoB), total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), direct low-density lipoprotein cholesterol (LDL-C), lipoprotein A [Lp(a)], and triglycerides (TG)) and risk of early AMD. In total, 14,034 cases and 91,214 controls of European ancestry were included in the analysis (number of SNPs = 11,304,110).

RESULTS

MR estimates revealed that a higher HDL-C level is strongly associated with increased risk of early AMD (OR = 1.25, 95% CI: 1.15-1.35, P = 2.61 × 10^-8). In addition, level of ApoA is also positively associated with risk of early AMD (OR = 2.04, 95% CI: 1.50-2.77, P = 6.27 × 10^-6). Conversely, higher levels of TG significantly decrease the risk of early AMD (OR = 0.77, 95% CI: 0.71-0.84, P = 5.02 × 10^-10). Sensitivity analyses further supported these associations. Moreover, multivariable MR analyses, adjusted for the effects of correlated lipid biomarkers, yielded similar results.

CONCLUSION

This study identifies causal relationships between elevated circulating HDL-C/ApoA levels and increased risk of early AMD, in addition to finding that TG specifically reduces the risk of early AMD. These findings contribute to a better understanding of the role of lipid metabolism in drusen formation, particularly in early AMD development.

Near-Complete Drusen Resolution With Brolucizumab: A Mechanism for Proinflammatory Mediated Drusen Clearance?

A 68-year-old woman with macular drusen was diagnosed with neovascular age-related macular degeneration (AMD) and treated with intravitreal brolucizumab. She had a good response to treatment with reduced height of the pigment epithelial detachment, and a good visual outcome. Remarkably, she had a near-complete resolution of macular drusen, yet this was accompanied by the development of anterior uveitis. We propose a proinflammatory-based mechanism for the brolucizumab-induced drusen resorption. Identifying the biochemical pathways responsible could hold the potential to discover novel forms of therapy for the treatment of AMD. [Ophthalmic Surg Lasers Imaging Retina 2023;54:371-374.].

Association between Antihyperlipidemic Agent Use and Age-Related Macular Degeneration in Patients with Hyperlipidemia: A Population-Based Retrospective Cohort Study

Several studies have indicated that lipoproteins might contribute to the pathogenesis of age-related macular degeneration (AMD). In this population-based retrospective cohort study, patients with hyperlipidemia were divided into two groups (study groups I and II) based on whether or not they were receiving antihyperlipidemic agents. The comparison group included patients without hyperlipidemia who were randomly selected and matched with study group II patients. A Cox proportional hazard model was used to evaluate the risk of AMD among the groups. Patients with hyperlipidemia receiving antihyperlipidemic agents (study group I, n = 15,482) had a significantly increased AMD risk (adjusted hazard ratio (HR) = 1.23, 95% confidence interval (CI) = 1.04-1.45) compared to those not receiving antihyperlipidemic agents (study group II, n = 15,482). However, with an increase in cumulative exposure, a reduced risk of AMD was observed in patients using a defined daily dose of more than 721, with an adjusted HR of 0.34 (95% CI = 0.22-0.53, p < 0.001). Additionally, the adjusted HR of AMD for study group II was 1.40 (95% CI = 1.20-1.63, p < 0.001) relative to the comparison group (n = 61,928). In conclusion, the study results indicated that patients with hyperlipidemia have a higher AMD risk than patients without hyperlipidemia. Furthermore, patients with hyperlipidemia who received antihyperlipidemic agents had a significantly increased AMD risk. However, a dose-dependent reduction in the risk of AMD was observed in patients with hyperlipidemia using statins or/and fibrates.

Repurposing medications for treatment of age-related macular degeneration: Insights from novel approaches to data mining

The economic and visual burdens associated with age-related macular degeneration (AMD) are expected to significantly increase in the coming years. As of now, interventions to delay or prevent AMD are limited. Hence, there is an urgent and unmet need to expand our therapeutic tools for AMD in a manner, that is, both efficient and cost-effective. In this review, we consider the idea of drug repurposing, in which existing medications with other indications can be re-imagined for treating AMD. We detail the results of several population-level studies that have shown associations between several candidates and decreased risk of AMD development or progression. Such candidates include the more extensively studied metformin and statins, in addition to recently identified candidates fluoxetine and l-DOPA (levodopa) that show promise. We then briefly explore results from an advanced bioinformatics study, which provides further evidence that existing medications are associated with AMD risk genes. Many of these candidates warrant further study in prospective, clinical trials, where their potential causal relationships with AMD can be thoroughly assessed.

Transcriptomic Changes Predict Metabolic Alterations in LC3 Associated Phagocytosis in Aged Mice

LC3b (Map1lc3b) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b to promote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes, such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells, utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis, and neuroprotection. In a mouse model of retinal lipid steatosis-mice lacking LC3b (LC3b-/-), we observed increased lipid deposition, metabolic dysregulation, and enhanced inflammation. Herein, we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% downregulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism, and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with a potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.

Transcriptomic changes predict metabolic alterations in LC3 associated phagocytosis in aged mice

LC3b ( Map1lc3b ) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b, to pro-mote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis and neuroprotection. In a mouse model of retinal lipid steatosis - mice lacking LC3b ( LC3b ^-/- ), we observed increased lipid deposition, metabolic dysregulation and enhanced inflammation. Herein we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b ^-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% down-regulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.

Age-related macular degeneration

Age-related macular degeneration is an increasingly important public health issue due to ageing populations and increased longevity. Age-related macular degeneration affects individuals older than 55 years and threatens high-acuity central vision required for important tasks such as reading, driving, and recognising faces. Advances in retinal imaging have identified biomarkers of progression to late age-related macular degeneration. New treatments for neovascular age-related macular degeneration offer potentially longer-lasting effects, and progress is being made towards a treatment for atrophic late age-related macular degeneration. An effective intervention to slow progression in the earlier stages of disease, or to prevent late age-related macular degeneration development remains elusive, and our understanding of underlying mechanistic pathways continues to evolve.

The HIT Study—The Hydroxychloroquine Effect in the Treatment of Patients with Age-Related Macular Degeneration: A Randomized Controlled Trial

Background and Objectives: Decreased age-related macular degeneration (AMD) has been reported in individuals with rheumatoid arthritis treated with hydroxychloroquine (HCQ, plaquenil). Materials and Methods: In a randomized controlled trial with a parallel study design, we assessed visual acuity, central macular thickness measured with macular optical coherence tomography (OCT), and the number and size of drusen, following treatment with HCQ or a placebo in individuals with AMD. The patients received a daily dosage of 400 mg hydroxychloroquine (study group) or placebo (control group) during 12 months, and underwent complete ophthalmic examinations at 3, 6, 9, 12 and 24 months after initiation of treatment. Results: Of the 110 patients who were randomized to the treatment groups, 46 (29 females) in the study group and 50 (29 females) in the control group completed the study. The study group showed less visual acuity deterioration at two-year follow-up than did the control group (−0.03 ± 0.07 vs. −0.07 ± 0.07, p = 0.027). At two years after treatment initiation, the mean number of drusen per eye was lower for ARDS2 (8.1 vs. 12.3, p = 0.045) in the study group, compared to the control group. Compared to the control group, the proportion of eyes with increased drusen growth was smaller for both ARDS2 and ARDS3 drusen in the study group, and the proportion of the total drusen with growth was smaller for the study group as well: 32/46 eyes (70%) vs. 40/50 eyes (80%). Drusen volume growth, as calculated by the area and height measured with macular OCT, was also more reduced in the study than the control group (0.20 ± 0.15 vs. 0.23 ± 0.16 mm4, p = 0.05). None of the participants showed HCQ toxicity or adverse effects. Conclusion: Among patients with AMD, visual deterioration, the growth and the amount of drusen formation at two years after treatment initiation was less among those treated with HCQ than with a placebo. In this study, there was a negative association between HCQ treatment and wet AMD development.

P2X7-mediated alteration of membrane fluidity is associated with the late stages of age-related macular degeneration

We have shown deficits in monocyte phagocytosis from patients with age-related macular degeneration (AMD). Cell membrane fluidity is known to affect phagocytic capacity and leucocyte functionality more generally. Therefore, we examined membrane fluidity of peripheral blood leucocytes in human patients with AMD and in the P2X7 null mouse model of AMD using flow cytometry with a fluorescent probe for fluidity, TMA-DPH. The results showed that membrane fluidity was decreased in all leucocyte types of late AMD relative to healthy controls (HC) including monocytes, neutrophils and lymphocytes but this was not apparent in earlier stages of AMD. Further analysis of factors contributing to membrane fluidity indicated that pre-treatment of monocytes and lymphocytes with ATP greatly increased membrane fluidity in humans and mice. Evidence from P2X7 null mice and P2X7 antagonists confirmed that these ATP-driven increases in membrane fluidity were mediated by P2X7 but were not associated with the classic P2X7 functions of pore formation or phagocytosis. Analysis of P2X7 expression indicated that receptor levels were elevated in classic monocytes of late AMD patients, further suggesting the P2X7 may contribute to altered plasma membrane properties. Our findings identified a novel biological function of P2X7 in modulating membrane fluidity of leucocytes and demonstrated reduced membrane fluidity in cellular changes associated with the late stage of AMD.

Using Computational Drug-Gene Analysis to Identify Novel Therapeutic Candidates for Retinal Neuroprotection

Retinal cell death is responsible for irreversible vision loss in many retinal disorders. No commercially approved treatments are currently available to attenuate retinal cell loss and preserve vision. We seek to identify chemicals/drugs with thoroughly-studied biological functions that possess neuroprotective effects in the retina using a computational bioinformatics approach. We queried the National Center for Biotechnology Information (NCBI) to identify genes associated with retinal neuroprotection. Enrichment analysis was performed using ToppGene to identify compounds related to the identified genes. This analysis constructs a Pharmacome from multiple drug-gene interaction databases to predict compounds with statistically significant associations to genes involved in retinal neuroprotection. Compounds with known deleterious effects (e.g., asbestos, ethanol) or with no clinical indications (e.g., paraquat, ozone) were manually filtered. We identified numerous drug/chemical classes associated to multiple genes implicated in retinal neuroprotection using a systematic computational approach. Anti-diabetics, lipid-lowering medicines, and antioxidants are among the treatments anticipated by this analysis, and many of these drugs could be readily repurposed for retinal neuroprotection. Our technique serves as an unbiased tool that can be utilized in the future to lead focused preclinical and clinical investigations for complex processes such as neuroprotection, as well as a wide range of other ocular pathologies.

Using Advanced Bioinformatics Tools to Identify Novel Therapeutic Candidates for Age-Related Macular Degeneration

Purpose

Age-related macular degeneration (AMD) is the most common cause of aging-related blindness in the developing world. Although medications can slow progressive wet AMD, currently, no drugs to treat dry-AMD are available. We use a systems or in silico biology analysis to identify chemicals and drugs approved by the Food and Drug Administration for other indications that can be used to treat and prevent AMD.

Methods

We queried National Center for Biotechnology Information to identify genes associated with AMD, wet AMD, dry AMD, intermediate AMD, and geographic atrophy to date. We combined genes from various AMD subtypes to reflect distinct stages of disease. Enrichment analysis using the ToppGene platform predicted molecules that can influence AMD genes. Compounds without clinical indications or with deleterious effects were manually filtered.

Results

We identified several drug/chemical classes that can affect multiple genes involved in AMD. The drugs predicted from this analysis include antidiabetics, lipid-lowering agents, and antioxidants, which could theoretically be repurposed for AMD. Metformin was identified as the drug with the strongest association with wet AMD genes and is among the top candidates in all dry AMD subtypes. Curcumin, statins, and antioxidants are also among the top drugs correlating with AMD-risk genes.

Conclusions

We use a systematic computational process to discover potential therapeutic targets for AMD. Our systematic and unbiased approach can be used to guide targeted preclinical/clinical studies for AMD and other ocular diseases.

Translational Relevance

Advanced bioinformatics models identify novel chemicals and approved drug candidates that can be efficacious for different subtypes of AMD.

Novel Epigenetic Clock Biomarkers of Age-Related Macular Degeneration

Age-Related Macular Degeneration (AMD) is a bilateral ocular condition resulting in irreversible vision impairment caused by the progressive loss of photoreceptors in the macula, a region at the center of the retina. The progressive loss of photoreceptor is a key feature of dry AMD but not always wet AMD, though both forms of AMD can lead to loss of vision. Regression-based biological age clocks are one of the most promising biomarkers of aging but have not yet been used in AMD. Here we conducted analyses to identify regression-based biological age clocks for the retina and explored their use in AMD using transcriptomic data consisting of a total of 453 retina samples including 105 Minnesota Grading System (MGS) level 1 samples, 175 MGS level 2, 112 MGS level 3 and 61 MGS level 4 samples, as well as 167 fibroblast samples. The clocks yielded good separation among AMD samples with increasing severity score viz., MGS1-4, regardless of whether clocks were trained in retina tissue, dermal fibroblasts, or in combined datasets. Clock application to cultured fibroblasts, embryonic stem cells, and induced Pluripotent Stem Cells (iPSCs) were consistent with age reprograming in iPSCs. Moreover, clock application to in vitro neuronal differentiation suggests broader applications. Interesting, many of the age clock genes identified include known targets mechanistically linked to AMD and aging, such as GDF11, C16ORF72, and FBN2. This study provides new observations for retina age clocks and suggests new applications for monitoring in vitro neuronal differentiation. These clocks could provide useful markers for AMD monitoring and possible intervention, as well as potential targets for in vitro screens.

The Relationship between Statin and Risk of Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis

Introduction and Aim. Age-related macular degeneration (AMD) is one of the leading causes of blindness and visual defect, particularly in elderly people across the world. This meta-analysis aimed at investigating the relationship between statin and the risk of AMD. Methods. Web of Science, PubMed, and Scopus databases were searched for articles that addressed the relationship between statin consumption and risk of AMD. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model. Subgroup analyses and sensitivity analyses were also conducted. Cochran’s Q test and the I2 statistic were used to evaluate the heterogeneity. To assess potential publication bias, Begg’s test was used. Results. In total, 22 studies were reviewed in the meta-analysis that included 2063195 participants and 313702 (15.20%) AMD patients compared to individuals not receiving statins. The OR of AMD in statin-receiving participants was 0.93 (95% CI; 0.83–1.05, $P=0.225$ ). The OR of AMD in those that received statins was 0.92 (95% CI; 0.75–1.13, $P=0.440$ ) in case-control studies, 0.95 (95% CI; 0.82–1.09, $P=0.458$ ) in cohort studies, 0.951 (95% CI; 0.59–1.53, $P=0.831$ ) in cross-sectional studies, 0.94 (95% CI; 0.80–1.10, $P=0.468$ ) in North America, 0.81 (95% CI; 0.54–1.21, $P=0.308$ ) in Europe, 1.05 (95% CI; 0.94–1.18, $P=0.362$ ) in Asia, and 0.52 (95% CI; 0.26–1.04, $P=0.125$ ) in Australia. No publication bias was observed in this study ( $P=0.114$ ). Conclusion. According to the results of this study, taking statins does not increase or decrease the risk of AMD development. Therefore, this drug group cannot be considered a protective or risk factor for the occurrence of AMD.

Serum Cholesterol Efflux Capacity in Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

Purpose

To investigate serum cholesterol efflux capacity (the ability of the serum to accept cholesterol) and factors that regulate it using nuclear magnetic resonance-quantified measures of lipoprotein particle composition and size and apolipoproteins metrics in patients with age-related macular degeneration (AMD).

Design

Case-control study.

Participants

Four hundred two serum samples from 80 patients with early AMD (eAMD), and 212 patients with neovascular AMD (nAMD), including 80 with typical nAMD (tAMD) and 132 with polypoidal choroidal vasculopathy (PCV), and 110 age- and gender matched control participants.

Methods

Serum from participants showed cholesterol efflux capacity measured using in vitro cell assays and lipoprotein subfractions measured using nuclear magnetic resonance (Nightingale, Ltd). Associations between cholesterol efflux capacity (measured in percentage) and lipid subfractions were investigated in the patients and control participants.

Main Outcome Measures

Cholesterol efflux capacity and lipid subfractions in control, eAMD, and nAMD. Associations between HDL subfractions and cholesterol efflux capacity.

Results

Cholesterol efflux capacity was higher in patients with eAMD (68.0 ± 11.3% [mean ± standard deviation]) and nAMD (75.9 ± 27.7%) than in the control participants (56.9 ± 16.7%) after adjusting for age, gender, and use of lipid-lowering drug (P < 0.0001). Nuclear magnetic resonance lipidomics demonstrated that the mean diameter of HDL was larger both in eAMD (9.96 ± 0.27 mm [mean ± standard deviation]) and PCV (9.97 ± 0.23 mm) compared with that of the control participants (9.84 ± 0.24 mm; P = 0.0001 for both). Among the 28 HDL subfractions, most of the small, medium, and large HDLs, but none of the 7 extra large HDLs fractions, were associated moderately with cholesterol efflux capacity in eAMD and PCV (R = 0.149-0.277).

Conclusions

Serum cholesterol efflux capacity was increased in eAMD and PCV, but not tAMD, possibly reflecting differential underlying pathophysiologic features of lipid dysregulation in tAMD and PCV. Further studies should be directed toward investigating the diverse biological activities of HDL in AMD, including macular pigment transport, regulation of inflammation, and local cholesterol transport system.

Complete Resolution of Central Soft Drusen without Geographic Atrophy or Choroidal Neovascularization

The treatment and prevention of dry age-related macular degeneration (AMD) traditionally involve lifestyle modifications and antioxidant supplementation, including the AREDS2 formula. We present a case of a woman with dry AMD in her right eye with several large, confluent central drusen on her exam and optical coherence tomography B-scan. Over the course of a year, the drusen almost completely disappeared, but the retinal layers were preserved without the development of geographic atrophy or choroidal neovascularization. While the exact cause of this phenomenon is unclear, it was thought to be associated with this patient’s strict daily use of numerous dietary supplements. This case highlights the potential in exploring alternative medicine supplements in the treatment of AMD.

Dyslipidemia in age-related macular degeneration

Lipid-rich drusen are the sine qua non of age-related macular degeneration (AMD), the leading cause of blindness in older adults in the developed world. Efforts directed at uncovering effective therapeutic strategies have led to the hypothesis that altered lipid metabolism may play a pathogenic role in AMD. This hypothesis is supported by the fact that: (1) drusen, the hallmark histopathologic feature of AMD, are composed of lipids, (2) polymorphisms of genes involved in lipid homeostasis are associated with increased odds of AMD, (3) metabolomics studies show that patients with AMD have alterations in metabolites from lipid pathways, and (4) alterations in serum lipid profiles as a reflection of systemic dyslipidemia are associated with AMD. There is strong evidence that statins, which are well described for treating dyslipidemia and reducing risk associated with cardiovascular disease, may have a role for treating certain cohorts of AMD patients, but this has yet to be conclusively proven. Of interest, the specific changes in serum lipoprotein profiles associated with decreased cardiovascular risk (i.e., high HDL levels) have been shown in some studies to be associated with increased risk of AMD. In this review, we highlight the evidence that supports a role for altered lipid metabolism in AMD and provide our perspective regarding the remaining questions that need to be addressed before lipid-based therapies can emerge for specific cohorts of AMD patients.

Long-term effects of multimodality laser therapy in patient with drusenoid pigment epithelial detachment

Drusenoid pigment epithelial detachment is a condition characterized by separation of the retinal pigment epithelium from the underlying Bruch’s membrane due to formation of drusenoid deposits. The disorder represents the intermediate stage of the age-related macular degeneration, and is a risk factor for the age-related macular degeneration progression to late stage characterized by geographic atrophy, which results in the irreversible central vision loss. Management of patients with this disorder is in most cases limited to follow-up. The feasibility of using the multimodality low power mode laser therapy for treatment of drusenoid pigment epithelial detachment is reported. The results of laser photocoagulation of the retina demonstrate the morphological and functional recovery: retinal pigment epithelial detachment sealing, improvement of visual function, and restored retinal architecture.

Targeting Lipid Metabolism for the Treatment of Age-Related Macular Degeneration: Insights from Preclinical Mouse Models

Age-related macular degeneration (AMD) is a major leading cause of irreversible visual impairment in the world with limited therapeutic interventions. Histological, biochemical, genetic, and epidemiological studies strongly implicate dysregulated lipid metabolism in the retinal pigmented epithelium (RPE) in AMD pathobiology. However, effective therapies targeting lipid metabolism still need to be identified and developed for this blinding disease. To test lipid metabolism-targeting therapies, preclinical AMD mouse models are needed to establish therapeutic efficacy and the role of lipid metabolism in the development of AMD-like pathology. In this review, we provide a comprehensive overview of current AMD mouse models available to researchers that could be used to provide preclinical evidence supporting therapies targeting lipid metabolism for AMD. Based on previous studies of AMD mouse models, we discuss strategies to modulate lipid metabolism as well as examples of studies evaluating lipid-targeting therapeutics to restore lipid processing in the RPE. The use of AMD mouse models may lead to worthy lipid-targeting candidate therapies for clinical trials to prevent the blindness caused by AMD.

The Development of Macular Atrophy in Patients with Wet Age-Related Macular Degeneration Receiving Anti-VEGF Treatment

Age-related macular degeneration (AMD) is a leading cause of blindness. Late AMD can be classified into exudative (commonly known as wet AMD [wAMD]) or dry AMD, both of which may progress to macular atrophy (MA). MA causes irreversible vision loss and currently has no approved pharmacological treatment. The standard of care for wAMD is treatment with anti-vascular endothelial growth factors (VEGF). However, recent evidence suggests that anti-VEGF treatment may play a role in the development of MA. Therefore, it is important to identify risk factors for the development of MA in patients with wAMD. For example, excessive blockade of VEGF through intense use of anti-VEGF agents may accelerate the development of MA. Patients with type III macular neovascularisation (retinal angiomatous proliferation) have a particularly high risk of MA. These patients are characterised as having a pre-existing thin choroid (age-related choroidopathy), suggesting that the choroidal circulation is unable to respond to increased VEGF expression. Evidence suggests that subretinal fluid (possibly indicative of residual VEGF activity) may play a protective role. Patients receiving anti-VEGF agents must be assessed for overall risk of MA and there is an unmet medical need to prevent the development of MA without undertreating wAMD.

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.

Association between Statins and Retinal Vascular Occlusion: A Population-Based Cohort Study

Retinal vascular occlusion (RVO), including retinal arterial occlusion and retinal vein occlusion, is a common retinal vascular disease that causes visual disturbance. The exact pathogenesis of RVO remains unclear. In all types of RVO patients, hyperlipidemia is more than twofold more common than in controls. Statins have been used to control blood cholesterol levels and have been found to reduce the risk of cardiovascular morbidity and mortality. Moreover, the immunomodulatory functions of statins may play a role in treating inflammatory diseases. This study aimed to evaluate whether patients taking statins have a lower risk of developing RVO compared to patients not taking statins. Adult patients with statins usage on the index date identified from the Taiwan National Health Insurance Research Database (NHIRD) between 2000 and 2013 were included. A threefold matched group was selected using age, sex, and year of index date for comparison. During the mean follow-up period of 12.87 ± 1.88 years, the cumulative incidence of RVO was significantly lower in the statin-user group (29.96 per 105 person-years [PYs]) than in the non-statin-user group (39.35 per 105 PYs). The results showed a lower cumulative incidence rate of RVO in patients prescribed statins than in those not prescribed statins (log-rank test, p = 0.020). The adjusting hazard ratio (HR) was significantly greater for RVO in the statin-user group (adjusted HR, 0.704; 95% CI, 0.591-0.873). Statin users had a decreased risk for all types of RVO development, including central retinal artery occlusion, arterial branch occlusion, central retinal vein occlusion, and branch retinal vein occlusion. In conclusion, patients undergoing statin treatment have a lower risk of developing RVO compared to patients not taking statins.

Age-Related Macular Degeneration

A 78-year-old woman presents with vision changes in the right eye for one week. Specifically, she describes central blurring in her vision and bending or waviness in straight lines. She also reports increasing difficulty reading print and often feels that there are blind spots in her vision. How would you diagnose and treat this patient?

Statins and the progression of age-related macular degeneration in the United States

PURPOSE

To study the effect of statin exposure on the progression from non-exudative to exudative age-related macular degeneration (AMD).

METHODS

Retrospective cohort study of commercially insured patients diagnosed with non-exudative AMD (n = 231,888) from 2007 to 2015. Time-to-event analysis of the association between exposure to lipid-lowering medications and time from non-exudative AMD to exudative AMD diagnosis was conducted. Outcome measures included progression to exudative AMD, indicated by diagnosis codes for exudative AMD or procedural codes for intravitreal injections.

RESULTS

In the year before and after first AMD diagnosis, 11,330 patients were continuously prescribed lipid-lowering medications and 31,627 patients did not take any lipid-lowering medication. Of those taking statins, 21 (1.6%) patients were on very-high-dose lipophilic statins, 644 (47.6%) on high-dose lipophilic statins, and 689 (50.9%) on low-dose lipophilic statins. We found no statistically significant relationship between exposure to low (HR 0.89, 95% CI 0.83 to 1.38) or high-dose lipophilic statins (HR 1.12, 95% CI 0.86 to 1.45) and progression to exudative AMD. No patients taking very-high-dose lipophilic statins converted from non-exudative to exudative AMD, though this difference was not statistically significant due to the subgroup size (p = .23, log-rank test).

CONCLUSIONS

No statistically significant relationship was found between statin exposure and risk of AMD progression. Interestingly, no patients taking very-high-dose lipophilic statins progressed to exudative AMD, a finding that warrants further exploration.

Atorvastatin-loaded solid lipid nanoparticles as eye drops: proposed treatment option for age-related macular degeneration (AMD)

Statins, widely prescribed for cardiovascular diseases, are also being eyed for management of age-related macular degeneration (AMD). Poor bioavailability and blood-aqueous barrier may however limit significant ocular concentration of statins following oral administration. We for the first time propose and investigate local application of atorvastatin (ATS; representative statin) loaded into solid lipid nanoparticles (SLNs), as self-administrable eye drops. Insolubility, instability, and high molecular weight > 500 of ATS, and ensuring that SLNs reach posterior eye were the challenges to be met. ATS-SLNs, developed (2339/DEL/2014) using suitable components, quality-by-design (QBD) approach, and scalable hot high-pressure homogenization, were characterized and evaluated comprehensively for ocular suitability. ATS-SLNs were 8 and 12 times more bioavailable (AUC) in aqueous and vitreous humor, respectively, than free ATS. Three-tier (in vitro, ex vivo, and in vivo) ocular safety, higher corneal flux (2.5-fold), and improved stability (13.62 times) including photostability of ATS on incorporation in ATS-SLNs were established. Autoclavability and aqueous nature are the other highlights of ATS-SLNs. Presence of intact fluorescein-labeled SLNs (F-SLNs) in internal eye tissues post–in vivo application as eye drops provides direct evidence of successful delivery. Perinuclear fluorescence in ARPE-19 cells confirms the effective uptake of F-SLNs. Prolonged residence, up to 7 h, was attributed to the mucus-penetrating nature of ATS-SLNs.

Preliminary Investigation on Simvastatin-Loaded Polymeric Micelles in View of the Treatment of the Back of the Eye

There is increasing consensus in considering statins beneficial for age-related macular degeneration and in general, for immune and inflammatory mediated diseases affecting the posterior segment of the eye. However, all available data relate to oral administration, and safety and effectiveness of statins directly administered to the eye are not yet known, despite their ophthalmic administration could be beneficial. The aim was the development and the characterization of polymeric micelles based on TPGS or TPGS/poloxamer 407 to increase simvastatin solubility and stability and to enhance the delivery of the drug to the posterior segment of the eye via trans-scleral permeation. Simvastatin was chosen as a model statin and its active hydroxy acid metabolite was investigated as well. Results demonstrated that polymeric micelles increased simvastatin solubility at least 30-fold and particularly TPGS/poloxamer 407 mixed micelles, successfully stabilized simvastatin over time, preventing the hydrolysis when stored for 1 month at 4 °C. Furthermore, both TPGS (1.3 mPas) and mixed micelles (33.2 mPas) showed low viscosity, suitable for periocular administration. TPGS micelles resulted the best performing in delivery simvastatin either across conjunctiva or sclera in ex vivo porcine models. The data pave the way for a future viable ocular administration of statins.

The effects of eight serum lipid biomarkers on age-related macular degeneration risk: a Mendelian randomization study

BACKGROUND

Age-related macular degeneration (AMD) is a leading cause of vision loss. Whereas lipids have been studied extensively to understand their effects on cardiovascular diseases, their relationship with AMD remains unclear.

METHODS

Two-sample Mendelian randomization (MR) analyses were performed to systematically evaluate the causal relationships between eight serum lipid biomarkers, consisting of apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB), total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), direct low-density lipoprotein cholesterol (LDL-C), lipoprotein A [Lp(a)], triglycerides (TG) and non-HDL cholesterol (non-HDL-C), and the risk of different AMD stages and subtypes. We derived 64-407 genetic instruments for eight serum lipid biomarkers in 419 649 participants of European descent from the UK Biobank cohort. We conducted genome-wide association studies (GWAS) for 12 711 advanced AMD cases [8544 choroidal neovascularization (CNV) and 2656 geographic atrophy (GA) specific AMD subtypes] and 5336 intermediate AMD cases with 14 590 controls of European descent from the International AMD Genomics Consortium.

RESULTS

Higher genetically predicted HDL-C and ApoA1 levels increased the risk of all AMD subtypes. LDL-C, ApoB, CHOL and non-HDL-C levels were associated with decreased risk of intermediate and GA AMD but not with CNV. Genetically predicted TG levels were associated with decreased risk of different AMD subtypes. Sensitivity analyses revealed no evidence for directional pleiotropy effects. In our multivariable MR analyses, adjusting for the effects of correlated lipid biomarkers yielded similar results.

CONCLUSION

These results suggest the role of lipid metabolism in drusen formation and particularly in AMD development at the early and intermediate stages. Mechanistic studies are warranted to investigate the utility of lipid pathways for therapeutic treatment in preventing AMD.

Lipid accumulation and protein modifications of Bruch's membrane in age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive retinal disease, which is the leading cause of blindness in western countries. There is an urgency to establish new therapeutic strategies that could prevent or delay the progression of AMD more efficiently. Until now, the pathogenesis of AMD has remained unclear, limiting the development of the novel therapy. Bruch's membrane (BM) goes through remarkable changes in AMD, playing a significant role during the disease course. The main aim of this review is to present the crucial processes that occur at the level of BM, with special consideration of the lipid accumulation and protein modifications. Besides, some therapies targeted at these molecules and the construction of BM in tissue engineering of retinal pigment epithelium (RPE) cells transplantation were listed. Hopefully, this review may provide a reference for researchers engaged in pathogenesis or management on AMD.

Histopathology of Age-Related Macular Degeneration and Implications for Pathogenesis and Therapy

Aging is associated with a number of histological changes in the choroid, Bruch's membrane, RPE, and neuroretina. Outside of the normal physiologic aging spectrum of changes, abnormal deposits such as basal laminar deposits, basal linear deposits, and soft drusen are known to be associated with AMD. Progression of AMD to advanced stages involving geographic atrophy, choroidal neovascularization, and/or disciform scars can result in debilitating vision loss. Knowledge of the angiogenic pathway and its components that stimulate neovascularization has led to the development of a new paradigm of intravitreal anti-VEGF pharmacotherapy in the management of neovascular AMD. Currently however, there are no available treatments for the modification of disease progression in non-neovascular AMD, or for the treatment of geographic atrophy. Further understanding of the histopathology of AMD and the molecular mechanisms that contribute to pathogenesis of the disease may reveal additional therapeutic targets.

Targeting of miR-33 ameliorates phenotypes linked to age-related macular degeneration

Abnormal cholesterol/lipid homeostasis is linked to neurodegenerative conditions such as age-related macular degeneration (AMD), which is a leading cause of blindness in the elderly. The most prevalent form, termed "dry" AMD, is characterized by pathological cholesterol accumulation beneath the retinal pigment epithelial (RPE) cell layer and inflammation-linked degeneration in the retina. We show here that the cholesterol-regulating microRNA miR-33 was elevated in the RPE of aging mice. Expression of the miR-33 target ATP-binding cassette transporter (ABCA1), a cholesterol efflux pump genetically linked to AMD, declined reciprocally in the RPE with age. In accord, miR-33 modulated ABCA1 expression and cholesterol efflux in human RPE cells. Subcutaneous delivery of miR-33 antisense oligonucleotides (ASO) to aging mice and non-human primates fed a Western-type high fat/cholesterol diet resulted in increased ABCA1 expression, decreased cholesterol accumulation, and reduced immune cell infiltration in the RPE cell layer, accompanied by decreased pathological changes to RPE morphology. These findings suggest that miR-33 targeting may decrease cholesterol deposition and ameliorate AMD initiation and progression.

Incidence and Risk Factors of Reticular Pseudodrusen Using Multimodal Imaging

Importance

Although retinal multimodal imaging is needed for diagnosing reticular pseudodrusen (RPD), the incidence of RPD in the general population typically has been assessed only using fundus photographs, which may underestimate their incidence.

Objectives

To describe the incidence of RPD using retinal color photographs, spectral-domain optical coherence tomography scans, fundus autofluorescence, and near-infrared reflectance images among individuals 77 years of age or older and to analyze the associated risk factors of RPD.

Design, Setting, and Participants

The ALIENOR (Antioxydants, Lipides Essentiels, Nutrition et Maladies Oculaires) Study is a cohort of French individuals 77 years of age or older. Data for this study were collected between February 22, 2011, and February 15, 2017, with a mean (SD) follow-up of 3.7 (1.0) years (range, 1.2-5.6 years). At baseline, 501 individuals were eligible to participate. Of 1002 eyes, 197 had prevalent RPD, advanced age-related macular degeneration, or ungradable images. Of the remaining 805 eyes, 333 were missing follow-up data; therefore, the statistical analyses included data from 472 eyes. Data management and statistical analyses were performed between March 15, 2017, and April 5, 2019.

Main Outcomes and Measures

Reticular pseudodrusen were considered as present if detected by at least 2 of the following imaging methods: color fundus photographs, fundus autofluorescence, near-infrared reflectance, and spectral-domain optical coherence tomography images.

Results

Of the 472 eyes analyzed, 263 (55.7%) were from female participants, and the mean (SD) age was 81.9 (3.2) years. Forty-three eyes developed RPD, corresponding to an annual incidence rate of 2.9% (95% CI, 1.9%-4.4%) per participant and an estimated 5-year risk of 13.5%. In multivariable analysis, 4 risk factors of incident RPD were identified: subfoveal choroidal thinning (hazard ratio [HR], 0.99; 95% CI, 0.99-1.00 per 10-μm decrease in thickness; P = .02) and the presence of the minor allelic variants rs10490924 for ARMS2 (HR, 3.57; 95% CI, 1.80-7.10; P < .001), rs1061170 for CFH (HR, 2.12; 95% CI, 1.02-4.41; P = .04), and rs10468017 for LIPC (HR, 2.57; 95% CI, 1.37-4.82; P = .003). Lipophilic statin therapy was associated with a lower incidence of RPD (HR, 0.13; 95% CI, 0.02-0.74; P = .02).

Conclusions and Relevance

With the use of multimodal imaging, the RPD incidence rate was higher than previously reported in other population-based studies using fundus color images. Individuals with subfoveal choroidal thinning or carrying minor allelic variants for ARMS2, CFH, or LIPC had an increased risk for RPD, whereas lipophilic statin therapy was associated with a lower incidence.

Biometrics, Impact, and Significance of Basal Linear Deposit and Subretinal Drusenoid Deposit in Age-Related Macular Degeneration

Purpose

Basal linear deposit (BLinD) is a thin layer of soft drusen material. To elucidate the biology of extracellular deposits conferring age-related macular degeneration (AMD) progression risk and inform multimodal clinical imaging based on optical coherence tomography (OCT), we examined lipid content and regional prevalence of BLinD, soft drusen, pre-BLinD, and subretinal drusenoid deposit (SDD) in AMD and non-AMD aged eyes. We estimated BLinD volume and illustrated its relation to type 1 macular neovascularization (MNV).

Methods

Donor eyes were classified as early to intermediate AMD (n = 25) and age-matched controls (n = 54). In high-resolution histology, we assessed BLinD/soft drusen thickness at 836 and 1716 locations in AMD and control eyes, respectively. BLinD volume was estimated using solid geometry in donor eyes, one clinically characterized.

Results

BLinD, drusen, type 1 MNV, and fluid occupy the sub-RPE-basal laminar space. BLinD volume in a 3-mm diameter circle may be as much as 0.0315 mm3. Osmophilic lipid was more concentrated in BLinD/drusen than SDD. In the fovea, BLinD/drusen was prevalent in AMD eyes; pre-BLinD was prevalent in control eyes. SDD was low in the fovea and high in perifovea, especially in AMD eyes.

Conclusions

Although invisible, BLinD may presage type 1 MNV. BLinD volume approaches the criterion OCT drusen volume of 0.03 mm3 for AMD progression risk. BLinD culminates years of subfoveal lipid accumulation. SDD is detected relatively late in life, with currently unknown precursors. Deposit topography suggests one outer retinal lipid recycling system serving specialized cone and rod physiology, and its dysregulation in AMD is due to impaired transfer to the circulation.

Medical Compliance of Fibrate and the Decreased Risk of Age-Related Macular Degeneration in Dyslipidemia-Related Diseases: A Population-Based Cohort Study

The purpose of the current study is to evaluate the incidence of age-related macular degeneration (AMD) in dyslipidemia-related diseases with or without the use of fibrate. Patients were defined as dyslipidemia-related diseases according to the diagnostic code and lab exam arrangement, then the population was divided into those with fibrate application and those without via 1:2 ratios of propensity-score matching. The primary outcome is the development of AMD after dyslipidemia-related diseases by the Cox proportional hazard regression. Besides, the relationship between the medical compliance of fibrate, presented as medical possession ratio (MPR), and the AMD development was also analyzed. A total of 22,917 patients and 45,834 individuals were enrolled in the study and control groups. There were 572 and 1181 events of any AMD development in the study and control groups which showed identical risk of AMD (aHR: 0.94, 95% CI: 0.85–1.04). However, a reduced risk of any AMD was found in those patients reached a baseline MPR more than 20% (aHR: 0.729, 95% CI: 0.599–0.887, p = 0.0016) and overall MPR more than 5% three years after the diagnosis of dyslipidemia-related diseases (aHR: 0.712, 95% CI: 0.557–0.909, p = 0.0065). Besides, a lower risk of dry-AMD was also found in those patients with the above conditions (aHR: 0.736, 95% CI: 0.599–0.906, p = 0.0038 and aHR: 0.721, 95% CI: 0.557–0.934, p = 0.0133, respectively). In conclusion, the use of fibrate with fair initial medical compliance will decrease the incidence of AMD in patients with dyslipidemia-related diseases, especially for the development of dry-AMD.

Alterations of retinal thickness measured by optical coherence tomography correlate with neurophysiological measures in diabetic polyneuropathy

AIMS/INTRODUCTION

Diabetic polyneuropathy (DPN) and diabetic retinopathy (DR) are traditionally regarded as microvascular complications. However, these complications may share similar neurodegenerative pathologies. Here we evaluate the correlations in the severity of DPN and changes in the thickness of neuroretinal layers to elucidate whether these complications exist at similar stages of progression.

MATERIALS AND METHODS

A total of 43 patients with type 2 diabetes underwent a nerve conduction study (NCS), a macular optical coherence tomography, and a carotid artery ultrasound scan. Diabetic polyneuropathy was classified according to Baba's classification using NCS. The retina was automatically segmented into four layers; ganglion cell complex (GCC), inner nuclear layer/outer plexiform layer (INL/OPL), outer nuclear layer/photoreceptor inner and outer segments, and retinal pigment epithelium (RPE). The thickness of each retinal layer was separately analyzed for the fovea and the parafovea.

RESULTS

Fourteen patients were classified as having moderate to severe diabetic polyneuropathy. The thicknesses of the foveal and parafoveal INL/OPL increased in patients with diabetic polyneuropathy compared with patients without. The thickness of the parafoveal retinal pigment epithelium decreased in patients with diabetic polyneuropathy. The thinning of parafoveal ganglion cell complex and foveal and parafoveal retinal pigment epithelium were positively correlated with deterioration of nerve functions in the nerve conduction study, but the thickening of INL/OPL was positively correlated with the nerve function deterioration. The thinning of parafoveal ganglion cell complex and foveal retinal pigment epithelium were positively correlated with the thickening of the carotid intima-media.

CONCLUSIONS

Depending on the progression of diabetic polyneuropathy, the ganglion cell complex and retinal pigment epithelium became thinner and the INL/OPL became thicker. These retinal changes might be noteworthy for pathological investigations and for the assessment of diabetic polyneuropathy and diabetic retinopathy.

Acadesine suppresses TNF-α induced complement component 3 (C3), in retinal pigment epithelial (RPE) cells

Rationale

Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness in the developed world. Aging, inflammation and complement dysregulation affecting the retinal pigment epithelium (RPE), are considered significant contributors in its pathogenesis and several evidences have linked tumor necrosis factor alpha (TNF-α) and complement component 3 (C3) with AMD. Acadesine, an analog of AMP and an AMP-activated protein kinase (AMPK) activator, has been shown to have cytoprotective effects in human clinical trials as well as having anti-inflammatory and anti-vascular exudative effects in animals. The purpose of this study was to evaluate if acadesine is able to suppress TNF-α induced C3 in RPE cells.

Methods

ARPE-19 and human primary RPE cells were cultured and allowed to grow to confluence. TNF-α was used for C3 induction in the presence or absence of acadesine. Small molecule inhibitors and siRNA were used to determine if acadesine exerts its effect via the extracellular or intracellular pathway and to evaluate the importance of AMPK for these effects. The expression level of C3 was determined by immunoblot analysis.

Results

Acadesine suppresses TNF-α induced C3 in a dose dependent manner. When we utilized the adenosine receptor inhibitor dipyridamole (DPY) along with acadesine, acadesine’s effects were abolished, indicating the necessity of acadesine to enter the cell in order to exert it’s action. However, pretreatment with 5-iodotubericidin (5-Iodo), an adenosine kinase (AK) inhibitor, didn’t prevent acadesine from decreasing TNF-α induced C3 expression suggesting that acadesine does not exert its effect through AMP conversion and subsequent activation of AMPK. Consistent with this, knockdown of AMPK α catalytic subunit did not affect the inhibitory effect of acadesine on TNF-α upregulation of C3.

Conclusions

Our results suggest that acadesine suppresses TNF-α induced C3, likely through an AMPK-independent pathway, and could have potential use in complement over activation diseases.

The effect of long-term systemic immunosuppressive drug use on druse formation: a new perspective to age-related macular degeneration

Background/aim

To evaluate the effect of the long-term use of systemic immunosuppressive drugs on druse formation in patients aged over 50 years.

Materials and methods

The current retrospective cohort study includes 420 eyes of 420 patients. 210 eyes of 210 patients who used immunosuppressive drugs (Group 1) at least for the last 5 years and 210 eyes of 210 control patients (Group 2) who did not use any drugs were compared. All patients were older than 50 years and selected among patients who were followed by rheumatology and ophthalmology clinic at a tertiary university hospital. All patients had complete ophthalmic examination, fundus photography and optical coherence tomography (OCT). The primary outcome of this study is the difference in macular and paramacular druse formation rates between two groups.

Results

Small, intermediate, large, soft, and paramacular druse formation rates were significantly lower in Group 1 than those in Group 2 (P = 0.028, P = 0.001, P = 0.001, P = 0.001, and P = 0.001, respectively).

Conclusion

Patients who used long-term systemic immunosuppressive drugs had significantly lower hard and soft druse formation rate than age and sex matched control subjects.

An exploratory study to evaluate visual function endpoints in non-advanced age-related macular degeneration

Background

To prevent irreversible vision loss in age-related macular degeneration (AMD), it is critical to detect retinal dysfunction before permanent structural loss occurs. In the current study we evaluated a series of visual function tests to identify potential endpoints to detect visual dysfunction in non-advanced AMD.

Methods

A series of visual function tests were performed on 23 non-advanced AMD subjects (AREDS grade 1–4 on simplified scale) and 34 age-matched normals (AREDS grade 0). Tests included some commonly used endpoints such as ETDRS visual acuity (VA), low luminance (LL) 2.0ND ETDRS VA, MNREAD as well as newly developed tests such as the Ora-VCF™ test, Ora-tablet reading test, color sensitivity etc. Differences between the two groups were compared for each test. Test-retest repeatability and reproducibility was assessed on a subset of subjects and percent agreement was calculated.

Results

There was no difference in standard ETDRS VA between non-advanced AMD (0.06 ± 0.02 logMAR) and normal groups (0.04 ± 0.02 logMAR) (p = 0.57). LL 2.0 ETDRS VA and MNREAD showed no difference between the groups (p > 0.05). Ora-VCF™ test was significantly worse in the non-advanced AMD group compared to normals (0.67 ± 0.07 in AMD; 0.45 ± 0.04 in normals, p = 0.005). Non-advanced AMD subjects also had significantly worse reading performance using the Ora-tablet with LL 2.0ND (114.55 ± 11.22 wpm in AMD; 145.17 ± 9.55 wpm in normals p = 0.049). No significant difference between the groups was noted using other tests. Repeatability was 82% for Ora-VCF™ test and 92% for Ora-tablet LL 2.0ND reading. Reproducibility was 89% for both Ora-VCF™ test and Ora-tablet LL 2.0ND reading.

Conclusion

While there was no significant difference between non-advanced AMD and normal groups using some current common endpoints such as ETDRS VA, LL 2.0 ETDRS VA or MNREAD, Ora-VCF™ test and Ora-tablet LL 2.0ND reading tests were able to identify significant visual dysfunction in non-advanced AMD subjects. These tests show promise as endpoints for AMD studies.

REvisiting Lipids in REtinal Diseases: A Focused Review on Age-related Macular Degeneration and Diabetic Retinopathy

Dyslipidemia refers to an abnormal amount of lipid in the blood, and the total cholesterol level is defined as the sum of high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol, and very-LDL cholesterol concentrations. In Korea, the westernization of lifestyle habits in recent years has caused an increase in the incidence of dyslipidemia, which is an important risk factor of cardiovascular disease (CVD). Several studies have been conducted on how dyslipidemia affects not only CVD, but also chorioretinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. Recently, a pathological model of AMD was proposed under the assumption that AMD proceeds through a mechanism similar to that of atherosclerotic CVD. However, controversy remains regarding the relationship between chorioretinal diseases and lipid levels in the blood, and the effects of lipid-lowering agents. Herein, we summarize the role of lipids in chorioretinal diseases. In addition, the effects of lipid-lowering agents on the prevention and progression of chorioretinal diseases are presented.

Complement activation, lipid metabolism, and mitochondrial injury: Converging pathways in age-related macular degeneration

The retinal pigment epithelium (RPE) is the primary site of injury in non-neovascular age-related macular degeneration or dry AMD. Polymorphisms in genes that regulate complement activation and cholesterol metabolism are strongly associated with AMD, but the biology underlying disease-associated variants is not well understood. Here, we highlight recent studies that have used molecular, biochemical, and live-cell imaging methods to elucidate mechanisms by which aging-associated insults conspire with AMD genetic risk variants to tip the balance towards disease. We discuss how critical functions including lipid metabolism, autophagy, complement regulation, and mitochondrial dynamics are compromised in the RPE, and how a deeper understanding of these mechanisms has helped identify promising therapeutic targets to preserve RPE homeostasis in AMD.

Patients with myeloproliferative neoplasms and high levels of systemic inflammation develop age-related macular degeneration

BACKGROUND

Epidemiological data show that myeloproliferative neoplasms (MPNs) are associated with increased risk of neovascular age-related macular degeneration (AMD). However, knowledge about the retinal findings in these patients is lacking. This study was conducted to examine retinal ageing and the prevalence of a hallmark of AMD; drusen, in patients with MPNs. Further, we examine the role of chronic systemic inflammation, considered central in both AMD and MPNs.

METHODS

In this single-centre cross-sectional study, we consecutively enrolled 200 patients with MPNs. The study was divided into three substudies. Firstly, we obtained colour fundus photographs from all patients to evaluate and compare the prevalence of drusen with the published estimates from three large population-based studies. Secondly, to evaluate age-related changes in the various retinal layers, optical coherence tomography images were obtained from 150 of the patients and compared to a healthy control group, from a previous study. Thirdly, venous blood was sampled from 63 patients to determine the JAK2V617F allele burden and neutrophil-to-lymphocyte ratio (NLR), a marker of systemic inflammation, in MPN patients with and without drusen.

FINDINGS

Patients with MPNs had an increased risk of having large drusen compared to the three population-based studies OR 5·7 (95%CI, 4·1-8·0), OR 6·0 (95%CI, 4·2-8·4) and OR 7·0 (95%CI, 5·0-9·7). Also, we found that the retinal site of drusen accumulation - the Bruch's-membrane-retinal-pigment-epithelium-complex was thicker compared to healthy controls, 0·43μm (95%CI 0·17-0·71, p = 0·0014), but there was no sign of accelerated retinal ageing in terms of thinning of the neuroretina. Further, we found that MPN patients with drusen had a higher level of systemic inflammation than MPN patients with no drusen (p = 0·0383).

INTERPRETATION

Patients with MPNs suffer from accelerated accumulation of subretinal drusen and therefore AMD from an earlier age than healthy individuals. We find that the retinal changes are located only between the neuroretina and the choroidal bloodstream. Further, we find that the drusen accumulation is associated with a higher JAK2V617F allele burden and a higher NLR, suggesting that low-grade chronic inflammation is a part of the pathogenesis of drusen formation and AMD.

FUNDING

Fight for Sight, Denmark and Region Zealand's research promotion fund.