Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake

The role of nutritional factors in transitioning between early, mid, and late stages of age-related macular degeneration: prospective longitudinal analysis

BACKGROUND

Transitions between different stages of age-related macular degeneration (AMD) are not completely captured by traditional survival models with an end point of advanced AMD.

OBJECTIVES

This study aimed to explore the transitions from early and intermediate AMD to higher nonadvanced and advanced stages and determine the contributions of nutritional factors to these outcomes.

METHODS

Eyes with early or intermediate AMD at baseline, classified according to the Age-Related Eye Disease Study severity score, were included in this prospective longitudinal analysis. Foods and the biologically active nutrients associated with AMD [green leafy vegetables, fish, lutein/zeaxanthin (LZ), and ω-3 (n-3) fatty acids] were determined by a baseline food frequency questionnaire. Progression was defined as eyes transitioning to higher severity groups including nonadvanced and advanced stages over 5 y, confirmed at 2 consecutive visits. Cox proportional hazards models for foods and nutrients were analyzed adjusting for demographics, lifestyle, baseline macular status, a family history of AMD, caloric intake, and genetic risk.

RESULTS

Among 2697 eyes, 616 (23%) progressed to higher severity groups. In the food group model, higher intake of green leafy vegetables reduced incidence of transitions {hazard ratio [HR] (≥2.7 servings/wk compared with none): 0.75; 95% confidence interval [CI]: 0.59, 0.96; P = 0.02}. Higher fish intake was also protective [HR (greater than two 4-ounce servings/wk compared with <2): 0.79; 95% CI: 0.65, 0.95; P = 0.01]. In the nutrient model, LZ intake was protective [HR (≥2 mg/d compared with <2): 0.76; 95% CI: 0.60, 0.96; P = 0.02]. Higher intake of ω-3 fatty acids also tended to be beneficial [HR (≥0.7 g/wk compared with <0.7): 0.85; 95% CI: 0.71, 1.01; P = 0.06].

CONCLUSIONS

Increased consumption of green leafy vegetables, LZ, and fish nutritionally rich in ω-3 fatty acids during the initial stages of AMD may reduce rates of progression to higher severity of this debilitating disease. This trial was registered at clinicaltrials.gov as NCT00594672.

The role of immune modulators in age-related macular degeneration

We provide an overview of the expanding literature on the role of cytokines and immune mediators in pathophysiology of age-related macular degeneration (AMD). Although many immunological mediators have been linked to AMD pathophysiology, the broader mechanistic picture remains unclear with substantial variations in the levels of evidence supporting these mediators. Therefore, we reviewed the literature considering the varying levels of supporting evidence. A Medical Subject Headings (MeSH) term-based literature research was conducted in September, 2023, consisting of the MeSH terms "cytokine" and "Age-related macular degeneration" connected by the operator "AND". After screening the publications by title, abstract, and full text, a total of 146 publications were included. The proinflammatory cytokines IL-1β (especially in basic research studies), IL-6, IL-8, IL-18, TNF-α, and MCP-1 are the most extensively characterised cytokines/chemokines, highlighting the role of local inflammasome activation and altered macrophage function in the AMD pathophysiology. Among the antiinflammatory mediators IL-4, IL-10, and TGF-β were found to be the most extensively characterised, with IL-4 driving and IL-10 and TGF-β suppressing disease progression. Despite the extensive literature on this topic, a profound understanding of AMD pathophysiology has not yet been achieved. Therefore, further studies are needed to identify potential therapeutic targets, followed by clinical studies.

Association between fatty acid intake and age-related macular degeneration: a meta-analysis

Objective

The association of age-related macular degeneration (AMD) with the intake of high and low fatty acids (FAs), respectively, remains controversial. To this end, we performed a comprehensive meta-analysis of all the existing studies on the association of various intake levels of FA subtypes with AMD to determine these associations.

Methods

A systematic search of PubMed, Web of Science, Cochrane Library, and EMBASE databases was conducted from inception to September 2023. To compare the highest and lowest groups, odds ratio (OR) with 95% confidence intervals (CIs) was analyzed with a random-effects model/fixed-effects model.

Results

A high intake of omega-3 LCPUFAs (OR:0.67; 95%CI:[0.51, 0.88]; p = 0.004), DHA (OR:0.80; 95%CI:[0.70, 0.90]; p < 0.001), EPA (OR:0.91; 95%CI:[0.86, 0.97]; p = 0.004), and simultaneous intake of DHA and EPA (OR:0.79; 95%CI:[0.67, 0.93]; p = 0.035) significantly reduced the risk of overall AMD. Conversely, a high intake of trans-FAs (OR: 2.05; 95%CI: [1.29, 3.25]; p = 0.002) was significantly related to an increased risk of advanced AMD compared to the low-intake group. The subgroup analysis results are shown in the articles.

Conclusion

Increasing dietary intake of omega-3 LCPUFAs, specifically DHA, and EPA, or the simultaneous intake of DHA and EPA, is significantly associated with a reduced risk of overall AMD. Various subtypes of omega-3 also have a significant association with a reduced risk of different stages of AMD. The high intake of trans-fatty acids (TFAs) is significantly and positively correlated with the risk of advanced AMD. This could further support the idea that consuming foods rich in omega-3 LCPUFAs and reducing consumption of foods rich in TFAs may prevent AMD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023467227.

Crosstalk Between Microglia and Müller Glia in the Age-Related Macular Degeneration: Role and Therapeutic Value of Neuroinflammation

Age-related macular degeneration (AMD) is a progressive neurodegeneration disease that causes photoreceptor demise and vision impairments. In AMD pathogenesis, the primary death of retinal neurons always leads to the activation of resident microglia. The migration of activated microglia to the ongoing retinal lesion and their morphological transformation from branching to ameboid-like are recognized as hallmarks of AMD pathogenesis. Activated microglia send signals to Müller cells and promote them to react correspondingly to damaging stimulus. Müller cells are a type of neuroglia cells that maintain the normal function of retinal neurons, modulating innate inflammatory responses, and stabilize retinal structure. Activated Müller cells can accelerate the progression of AMD by damaging neurons and blood vessels. Therefore, the crosstalk between microglia and Müller cells plays a homeostatic role in maintaining the retinal environment, and this interaction is complicatedly modulated. In particular, the mechanism of mutual regulation between the two glia populations is complex under pathological conditions. This paper reviews recent findings on the crosstalk between microglia and Müller glia during AMD pathology process, with special emphasis on its therapeutic potentials.

A narrative review on dietary components and patterns and age-related macular degeneration

Age-related macular degeneration (AMD) is one of the most prevalent eye diseases among the ageing population worldwide. It is a leading cause of blindness in individuals over 55, particularly in industrialised Western countries. The prevalence of AMD increases with age, and genetic factors and environmental influences are believed to contribute to its development. Among the environmental factors, diet plays a significant role in AMD. This review explores the association between dietary components, dietary patterns and AMD. Various nutrients, non-nutrient substances and dietary models that have the potential to counteract oxidative stress and inflammation, which are underlying mechanisms of AMD, are discussed. Consuming fruits, vegetables, fish and seafood, whole grains, olive oil, nuts and low-glycaemic-index foods has been highlighted as beneficial for reducing the risk of AMD. Adhering to the Mediterranean diet, which encompasses these elements, can be recommended as a dietary pattern for AMD. Furthermore, the modulation of the gut microbiota through dietary interventions and probiotics has shown promise in managing 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.

[Nutrition and age-related macular degeneration]

Age-related macular degeneration (AMD) is the leading cause of vision loss in France and in other industrialized countries. AMD affects around 20 % of the population over the age of 80 years. This complex and multifactorial disease involves both genetic susceptibility and environmental factors. Smoking and nutrition are well-known modifiable risk factors for AMD. Numerous studies provide convincing arguments in favor of micronutrients to encourage dietary advice and the prescription of nutritional supplements containing antioxidant vitamins, lutein and omega-3 fatty acids. Attention to modifiable risk factors is of utmost importance to reduce progression to advanced AMD and associated medical and societal burdens.

Perspective: Challenges and Future Directions in Clinical Research with Nuts and Berries

Consumption of nuts and berries are considered part of a healthy eating pattern. Nuts and berries contain a complex nutrient profile consisting of essential vitamins and minerals, fiber, polyunsaturated fatty acids, and phenolics in quantities that improve physiological outcomes. The spectrum of health outcomes that may be impacted by the consumptions of nuts and berries includes cardiovascular, gut microbiome, and cognitive, among others. Recently, new insights regarding the bioactive compounds found in both nuts and berries have reinforced their role for use in precision nutrition efforts. However, challenges exist that can affect the generalizability of outcomes from clinical studies, including inconsistency in study designs, homogeneity of test populations, variability in test products and control foods, and assessing realistic portion sizes. Future research centered on precision nutrition and multi-omics technologies will yield new insights. These and other topics such as funding streams and perceived risk-of-bias were explored at an international nutrition conference focused on the role of nuts and berries in clinical nutrition. Successes, challenges, and future directions with these foods are presented here.

Associations between fatty acid intake and diabetic retinopathy in a Japanese population

Residents of Chikusei City, aged 40-74 years, underwent systemic and ophthalmological screening, and participants with diabetes were included in this analysis. Dietary intake was assessed using a food frequency questionnaire and calculated as a percentage of the total energy. The presence of diabetic retinopathy (DR) was defined as Early Treatment Diabetic Retinopathy Study levels ≥ 20 in either eye. The association between dietary fatty acid intake and DR has been examined in a cross-sectional study. Among the 647 diabetic participants, 100 had DR. The mean total fat and saturated fatty acid (SFA) intakes were 22.0% and 7.3% of the total energy intake, respectively. After adjusting for potential confounders, the highest quartiles of total fat and SFA intake were positively associated with the presence of DR compared with the lowest quartiles (odds ratios (95% confidence intervals), 2.61 (1.07-6.39), p for trend = 0.025, and 2.40 (1.12-5.17), p for trend = 0.013, respectively). No significant associations were found between DR prevalence and monounsaturated or unsaturated fatty acid intake. These results suggest that a high intake of fat and SFA may affect the development of DR, even in individuals whose total fat intake is generally much lower than that of Westerners.

Oxidative Stress and Antioxidants in Age-Related Macular Degeneration

Oxidative stress plays a crucial role in aging-related eye diseases, including age-related macular degeneration (AMD), cataracts, and glaucoma. With age, antioxidant reparative capacity decreases, and excess levels of reactive oxygen species produce oxidative damage in many ocular cell types underling age-related pathologies. In AMD, loss of central vision in the elderly is caused primarily by retinal pigment epithelium (RPE) dysfunction and degeneration and/or choroidal neovascularization that trigger malfunction and loss of photo-sensing photoreceptor cells. Along with various genetic and environmental factors that contribute to AMD, aging and age-related oxidative damage have critical involvement in AMD pathogenesis. To this end, dietary intake of antioxidants is a proven way to scavenge free radicals and to prevent or slow AMD progression. This review focuses on AMD and highlights the pathogenic role of oxidative stress in AMD from both clinical and experimental studies. The beneficial roles of antioxidants and dietary micronutrients in AMD are also summarized.

Effect of the Mediterranean Diet on Progression of Dry Form of Age-related Macular Degeneration

BACKGROUND/AIM

The aim of this study was to investigate the possible effect of the Mediterranean diet (Med Diet) on the progression of age-related macular degeneration (AMD) in patients with early or intermediate stages of dry AMD.

PATIENTS AND METHODS

The present study included 164 patients with early or intermediate dry AMD. Data collected included demographics, anthropometric data, ophthalmic and medical history. AMD progression was evaluated using patients' optical coherence tomography (OCT) and visual acuity. Using the MedDietScore, sample's attachment to Med Diet was evaluated, and distinguished into high and low. The association of supplement intake and adherence to Med Diet with AMD progression was investigated using logistic regression.

RESULTS

Sample's mean age was 73±7.4 years. A positive correlation was found between dietary supplementation and slowing of AMD progression, as well as between high adherence to Med Diet and slowing of AMD progression. In contrast, smokers had 51.4% higher risk of AMD progression (p=0.043). The rate of slowing AMD progression was higher in patients who followed Med Diet and received a dietary supplement, compared to patients who followed one or none of the aforementioned recommendations (p<0.001).

CONCLUSION

Adherence to the Med Diet could have a positive effect on delaying AMD progression in advanced stages, both in patients receiving or not antioxidants. Therefore, our study proposes to strengthen recommendations to AMD patients to follow a Med Diet.

Linkage between a plant-based diet and age-related eye diseases: a systematic review and meta-analysis

CONTEXT

An increased risk of age-related eye disease has been observed in individuals lacking a balanced diet. Following a plant-based diet may result in nutritional insufficiencies and negatively affect health if an effort is not made to ensure the consumption of fortified foods or specific supplements.

OBJECTIVE

The purpose of this article is to characterize the relationship between plant-based diets and age-related ocular outcomes among adults.

DATA SOURCES

A comprehensive literature review was performed using the MEDLINE, Embase, Cochrane, and PubMed databases up until December 19, 2021.

STUDY SELECTION

Studies that focused on observed visual changes due to a reduced intake of animal products and that included a minimum of 50 eyes were eligible for inclusion.

DATA EXTRACTION

Two levels of screening, quality assessment, and data extraction were conducted by 2 reviewers independently. The 21 studies identified from 814 unique studies progressed to data extraction and 15 were included in the quantitative analysis using STATA 15.0 fixed-effect and random-effect models computed on the basis of heterogeneity.

RESULTS

The 15 (n = 51 695 participants) assessed the impact of fish consumption, 8 studies (n = 28 753 participants) analyzed the effect of red meat intake, and 3 studies (n = 7723 participants) assessed the impact of omission of skim milk, poultry, and non-meat animal products and the presence of disease incidence as indicated by age-related macular degeneration or cataract development. Meta-analysis indicated regular consumption of fish (odds ratio [OR], 0.70; 95%CI, 0.62-0.79) and skim milk, poultry, and non-meat animal products (OR, 0.70; 95%CI, 0.61-0.79) reduced the risk of age-related eye disease development among adults. Consumption of red meat (OR, 1.41; 95%CI, 1.07-1.86) may increase the risk of age-related eye disease development.

CONCLUSION

A pescatarian diet is associated with the most favorable visual outcomes among adults, whereas consumption of red meat negatively affects ocular health. Results suggest a need for more initiatives promoting a healthy and balanced diet.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021269925.

Association Between Fatty Acid Intakes and Age-Related Macular Degeneration in a Japanese Population: JPHC-NEXT Eye Study

Purpose

To determine the associations between fatty acid intakes and the prevalence of age-related macular degeneration (AMD) under a population-based cross-sectional study.

Methods

Residents of Chikusei City aged ≥40 years underwent systemic and eye screening. AMD was graded according to a modified version of the Age-Related Eye Disease Study classification. Dietary intake was assessed using a food frequency questionnaire and was adjusted for total energy intake.

Results

Altogether, 10,788 eyes of 5394 participants, 2116 men (mean [standard deviation (SD)] age, 62.4 [9.4] years) and 3278 women (60.6 [9.5] years), were included. The mean daily total fat intakes were 52.8 g and 59.0 g in men and women, respectively. After adjustments for potential confounders, saturated fatty acid (SFA) intake was inversely associated with the prevalence of any AMD in men (for each energy-adjusted 1-SD increase: odds ratio [OR], 0.86; 95% confidence interval [CI], 0.74-1.00). Significant trends were found for decreasing odds ratios of AMD with increasing SFA, monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) intake (P for trend = 0.02, 0.04, and 0.04, respectively). In women, only a significant association was observed between the second quartile of linolenic acid intake and the prevalence of any AMD (OR, 0.78; 95% CI, 0.62-0.99).

Conclusions

We found an inverse association of SFA intake and a weak inverse association of MUFA and PUFA intakes with the prevalence of any AMD in a Japanese population.

Translational Relevance

Adequate fatty acid intake may be necessary to prevent or decelerate AMD.

Small hard drusen and associated factors in early seniority

PURPOSE

The purpose of this study was to examine the ocular and systemic risk profile of the fundus phenotype ≥ 20 small hard (macular) drusen (< 63 μm in diameter).

METHODS

This single-center, cross-sectional study of 176 same-sex twin pairs aged 30 to 80 (median 60) years was a component of a framework study of the transition from not having age-related macular degeneration to having early AMD. Drusen categories assessed using fundus photography and optical coherence tomography included small hard drusen (diameter < 63 μm), intermediate soft drusen (63-125 μm), and large soft drusen (> 125 μm), of which the soft drusen are compatible with a diagnosis of AMD.

RESULTS

Having ≥ 20 small hard drusen within or outside the macula was associated with increasing age, lower body mass index, shorter axial length, hyperopia, female sex, increasing high-density lipoprotein (HDL), high alcohol consumption, and with the presence of soft drusen.

CONCLUSIONS

Having ≥ 20 small hard drusen was associated with some AMD-related risk factors, but not with smoking, increasing body mass index, and higher blood pressure. Having ≥ 20 small hard drusen was also associated with soft drusen, in agreement with previous studies. These findings suggest that small hard drusen are not an early manifestation of AMD but the product of a distinct process of tissue alteration that promotes the development of AMD or some subtype thereof.

Heritability of retinal drusen in the Copenhagen Twin Cohort Eye Study

PURPOSE

To study age- and sex-adjusted heritability of small hard drusen and early age-related macular degeneration (AMD) in a population-based twin cohort.

METHODS

This was a single-centre, cross-sectional, classical twin study with ophthalmic examination including refraction, biometry, best-corrected visual acuity assessment, colour and autofluorescence fundus photography, and fundus optical coherence tomography. Grading and categorization of drusen was by diameter and location.

RESULTS

The study enrolled 176 same-sex pairs of twins of mean (SD) age 58.6 (9.9) years. The prevalence of the four phenotypes ≥20 small hard macular drusen (largest diameter < 63 μm), ≥20 small hard extramacular drusen, intermediate drusen (63-125 μm) anywhere, and large drusen (>125 μm) anywhere was 12.4%, 36.4%, 5.8%, and 8.4%, respectively, and the respective heritabilities, adjusted for age and sex, were 78.2% [73.5-82.9], 69.1% [62.3-75.9], 30.1% [4.1-56.1], and 65.6% [26.4-100]. Age trajectory analysis supported a gradual transition to larger numbers of small hard drusen with increasing age. The heritability of ≥20 small hard drusen was markedly lower than the 99% found in the 40% overlapping twin cohort that was seen 20 years earlier.

CONCLUSION

Numerous (≥20) small hard drusen and larger drusen that fit the definition of dry AMD were highly heritable. Small hard drusen counts increased with age. Decreasing heritability with increasing age suggests that the impact of behavioural and environmental factors on the development of small hard drusen increases with age.

An Exploratory Study Provides Insights into MMP9 and Aβ Levels in the Vitreous and Blood across Different Ages and in a Subset of AMD Patients

Matrix metalloproteinase-9 (MMP9) and total amyloid-beta (Aβ) are prospective biomarkers of ocular ageing and retinopathy. These were quantified by ELISA in the vitreous and blood from controls (n = 55) and in a subset of age-related macular degeneration (AMD) patients (n = 12) for insights and possible additional links between the ocular and systemic compartments. Vitreous MMP9 levels in control and AMD groups were 932.5 ± 240.9 pg/mL and 813.7 ± 157.6 pg/mL, whilst serum levels were 2228 ± 193 pg/mL and 2386.8 ± 449.4 pg/mL, respectively. Vitreous Aβ in control and AMD groups were 1173.5 ± 117.1 pg/mL and 1275.6 ± 332.9 pg/mL, whilst plasma Aβ were 574.3 ± 104.8 pg/mL and 542.2 ± 139.9 pg/mL, respectively. MMP9 and Aβ showed variable levels across the lifecourse, indicating no correlation to each other or with age nor AMD status, though the smaller AMD cohort was a limiting factor. Aβ and MMP9 levels in the vitreous and blood were unrelated to mean arterial pressure. Smoking, another modifiable risk, showed no association with vitreous Aβ. However, smoking may be linked with vitreous (p = 0.004) and serum (p = 0.005) MMP9 levels in control and AMD groups, though this did not reach our elevated (p = 0.001) significance. A bioinformatics analysis revealed promising MMP9 and APP/Aβ partners for further scrutiny, many of which are already linked with retinopathy.

Increased efficacy of dietary supplement containing wax ester-rich marine oil and xanthophylls in a mouse model of dry macular degeneration

Age-related macular degeneration (AMD) is nowadays considered among the retinal diseases whose clinical management lacks established treatment approaches, mainly for its atrophic (dry) form. In this respect, the use of dietary patterns enriched in omega-3 and antioxidant xanthophylls has emerged as a promising approach to counteract dry AMD progression although the prophylactic potential of omega-3 of fish origin has been discussed. Whether enriched availability of omega-3 and xanthophylls may increase the effectiveness of diet supplementation in preventing dry AMD remains to be fully established. The present study aims at comparing the efficacy of an existing orally administered formulation based on lutein and fish oil, as a source of omega-3, with a novel formulation providing the combination of lutein and astaxanthin with Calanus oil (COil), which contains omega-3 together with their precursors policosanols. Using a mouse model of dry AMD based on subretinal injection of polyethylene glycol (PEG)-400, we assessed the comparative efficacy of both formulations on PEG-induced major hallmarks including oxidative stress, inflammation, glial reactivity and outer retinal thickness. Dietary supplementation with both mixtures has been found to exert a significant antioxidant and anti-inflammatory activity as reflected by the overall amelioration of the PEG-induced pathological hallmarks. Noteworthy, the formulation based on COil appeared to be more protective than the one based on fish oil, presumably because of the higher bioavailability of omega-3 in COil. These results support the use of dietary supplements combining omega-3 and xanthophylls in the prevention and treatment of AMD and suggest that the source of omega-3 might contribute to treatment efficacy.

Absence of Gut Microbiota Is Associated with RPE/Choroid Transcriptomic Changes Related to Age-Related Macular Degeneration Pathobiology and Decreased Choroidal Neovascularization

Studies have begun to reveal significant connections between the gut microbiome and various retinal diseases, including age-related macular degeneration (AMD). As critical supporting tissues of the retina, the retinal pigment epithelium (RPE) and underlying choroid play a critical role in retinal homeostasis and degeneration. However, the relationship between the microbiome and RPE/choroid remains poorly understood, particularly in animal models of AMD. In order to better elucidate this role, we performed high-throughput RNA sequencing of RPE/choroid tissue in germ-free (GF) and specific pathogen-free (SPF) mice. Furthermore, utilizing a specialized laser-induced choroidal neovascularization (CNV) model that we developed, we compared CNV size and inflammatory response between GF and SPF mice. After correction of raw data, 660 differentially expressed genes (DEGs) were identified, including those involved in angiogenesis regulation, scavenger and cytokine receptor activity, and inflammatory response-all of which have been implicated in AMD pathogenesis. Among lasered mice, the GF group showed significantly decreased CNV lesion size and microglial infiltration around CNV compared to the SPF group. Together, these findings provide evidence for a potential gut-RPE/choroidal axis as well as a correlation with neovascular features of AMD.

High-Fat Diet Alters the Retinal Pigment Epithelium and Choroidal Transcriptome in the Absence of Gut Microbiota

Relationships between retinal disease, diet, and the gut microbiome have started to emerge. In particular, high-fat diets (HFDs) are associated with the prevalence and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). These effects are thought to be partly mediated by the gut microbiome, which modulates interactions between diet and host homeostasis. Nevertheless, the effects of HFDs on the retina and adjacent retinal pigment epithelium (RPE) and choroid at the transcriptional level, independent of gut microbiota, are not well-understood. In this study, we performed the high-throughput RNA-sequencing of germ-free (GF) mice to explore the transcriptional changes induced by HFD in the RPE/choroid. After filtering and cleaning the data, 649 differentially expressed genes (DEGs) were identified, with 616 genes transcriptionally upregulated and 33 genes downregulated by HFD compared to a normal diet (ND). Enrichment analysis for gene ontology (GO) using the DEGs was performed to analyze over-represented biological processes in the RPE/choroid of GF-HFD mice relative to GF-ND mice. GO analysis revealed the upregulation of processes related to angiogenesis, immune response, and the inflammatory response. Additionally, molecular functions that were altered involved extracellular matrix (ECM) binding, ECM structural constituents, and heparin binding. This study demonstrates novel data showing that HFDs can alter RPE/choroid tissue transcription in the absence of the gut microbiome.

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.

Inflammatory adipose activates a nutritional immunity pathway leading to retinal dysfunction

Age-related macular degeneration (AMD), the leading cause of irreversible blindness among Americans over 50, is characterized by dysfunction and death of retinal pigment epithelial (RPE) cells. The RPE accumulates iron in AMD, and iron overload triggers RPE cell death in vitro and in vivo. However, the mechanism of RPE iron accumulation in AMD is unknown. We show that high-fat-diet-induced obesity, a risk factor for AMD, drives systemic and local inflammatory circuits upregulating interleukin-1β (IL-1β). IL-1β upregulates RPE iron importers and downregulates iron exporters, causing iron accumulation, oxidative stress, and dysfunction. We term this maladaptive, chronic activation of a nutritional immunity pathway the cellular iron sequestration response (CISR). RNA sequencing (RNA-seq) analysis of choroid and retina from human donors revealed that hallmarks of this pathway are present in AMD microglia and macrophages. Together, these data suggest that inflamed adipose tissue, through the CISR, can lead to RPE pathology in AMD.

A High Fat "Western-style" Diet Induces AMD-Like Features in Wildtype Mice

Scope

The intake of a “Western‐style” diet rich in fats is linked with developing retinopathies including age‐related macular degeneration (AMD). Wildtype mice are given a high fat diet (HFD) to determine how unhealthy foods can bring about retinal degeneration.

Methods and results

Following weaning, female C57BL/6 mice are maintained on standard chow (7% kcal fat, n = 29) or a HFD (45% kcal fat, n = 27) for 12 months. Animals were sacrificed following electroretinography (ERG) and their eyes analyzed by histology, confocal immunofluorescence, and transmission electron microscopy. HFD mice become obese, but showed normal retinal function compared to chow‐fed controls. However, diminished β3tubulin labeling of retinal cross‐sections indicated fewer/damaged neuronal processes in the inner plexiform layer. AMD‐linked proteins clusterin and TIMP3 accumulated in the retinal pigment epithelium (RPE) and Bruch's membrane (BrM). Neutral lipids also deposited in the outer retinae of HFD mice. Ultrastructural analysis revealed disorganized photoreceptor outer segments, collapsed/misaligned RPE microvilli, vacuoles, convoluted basolateral RPE infolds and BrM changes. Basal laminar‐like deposits were also present alongside abnormal choroidal endothelial cells.

Conclusions

We show that prolonged exposure to an unhealthy “Western‐style” diet alone can recapitulate early‐intermediate AMD‐like features in wildtype mice, highlighting the importance of diet and nutrition in the etiology of sight‐loss.

Dietary Patterns and Their Associations with Intermediate Age-Related Macular Degeneration in a Japanese Population

This population-based cross-sectional study investigated the influence of dietary patterns on age-related macular degeneration (AMD) in a Japanese population. The Tsuruoka Metabolomics Cohort Study enrolled a general population aged 35–74 years from among participants in annual health check-up programs in Tsuruoka City, Japan. Eating habits were assessed using a food frequency questionnaire. Principal component analysis was used to identify dietary patterns among food items. The association between quartiles of scores for each dietary pattern and intermediate AMD was assessed using multivariate logistic regression models. Of 3433 participants, 415 had intermediate AMD. We identified four principal components comprising the Vegetable-rich pattern, Varied staple food pattern, Animal-rich pattern, and Seafood-rich pattern. After adjusting for potential confounders, higher Varied staple food diet scores were associated with a lower prevalence of intermediate AMD (fourth vs. first quartile) (OR, 0.63; 95% confidence interval [CI], 0.46–0.86). A significant trend of decreasing ORs for intermediate AMD associated with increasing Varied staple food diet scores was noted (p for trend = 0.002). There was no significant association between the other dietary patterns and intermediate AMD. In a Japanese population, individuals with a dietary pattern score high in the Varied staple food pattern had a lower prevalence of intermediate AMD.

A mutation in transmembrane protein 135 impairs lipid metabolism in mouse eyecups

Aging is a significant factor in the development of age-related diseases but how aging disrupts cellular homeostasis to cause age-related retinal disease is unknown. Here, we further our studies on transmembrane protein 135 (Tmem135), a gene involved in retinal aging, by examining the transcriptomic profiles of wild-type, heterozygous and homozygous Tmem135 mutant posterior eyecup samples through RNA sequencing (RNA-Seq). We found significant gene expression changes in both heterozygous and homozygous Tmem135 mutant mouse eyecups that correlate with visual function deficits. Further analysis revealed that expression of many genes involved in lipid metabolism are changed due to the Tmem135 mutation. Consistent with these changes, we found increased lipid accumulation in mutant Tmem135 eyecup samples. Since mutant Tmem135 mice have similar ocular pathologies as human age-related macular degeneration (AMD) eyes, we compared our homozygous Tmem135 mutant eyecup RNA-Seq dataset with transcriptomic datasets of human AMD donor eyes. We found similar changes in genes involved in lipid metabolism between the homozygous Tmem135 mutant eyecups and AMD donor eyes. Our study suggests that the Tmem135 mutation affects lipid metabolism as similarly observed in human AMD eyes, thus Tmem135 mutant mice can serve as a good model for the role of dysregulated lipid metabolism in AMD.

Red blood cell fatty acids and age-related macular degeneration in postmenopausal women

PURPOSE

To evaluate the relationship between red blood cell (RBC) polyunsaturated fatty acid (PUFA) levels, and dietary PUFA and fish intake, with prevalent and incident age-related macular degeneration (AMD) in a US cohort of postmenopausal women.

METHODS

This analysis included 1456 postmenopausal women from the Women's Health Initiative (WHI) Clinical Trials. RBC PUFAs were measured from fasting serum samples collected at WHI baseline. Dietary PUFAs and fish intake were assessed via food frequency questionnaires at baseline. There were 240 women who had prevalent AMD and 138 who self-reported AMD development over 9.5 years. Adjusted odds ratios and 95% confidence intervals were estimated for prevalent AMD by RBC PUFA levels, dietary PUFA intake, and frequency of fish consumption. Adjusted hazard ratios and 95% confidence intervals were estimated for incident AMD. A p-for-trend was estimated for continuous measures of dietary PUFA and fish intake.

RESULTS

No significant association was found between prevalent or incident AMD and RBC docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA), EPA, DHA, alpha-linolenic acid (ALA), linoleic acid (LA), or arachidonic acid (AA). A positive association was found between dietary intake of AA and odds of prevalent AMD (p-for-trend for continuous AA intake = 0.02) and between intake of LA/ALA and incident AMD (p-for-trend for continuous ratio of LA/ALA intake = 0.03). No statistically significant associations were found between AMD and dietary intake of PUFAs or fish.

CONCLUSIONS

RBC PUFAs were not associated with AMD in this cohort. Overall, dietary analyses of PUFAs supported this, excepting dietary AA intake and intake of LA in proportion to ALA of which there were trends of increased risk.

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.

Dietary omega-3 polyunsaturated fatty acids and fish intake and risk of age-related macular degeneration

BACKGROUND & AIMS

Epidemiologic studies are inconsistent regarding the association of dietary omega-3 polyunsaturated fatty acids (PUFA) and/or fish intake with risk of age-related macular degeneration (AMD) incidence and progression. The objective was to determine these associations by conducting a meta-analysis of available studies.

METHODS

Three electronic databases were searched for studies that quantified dietary omega-3 PUFA and/or fish intake from inception to December 2020 without language restriction. Three investigators independently assessed for inclusion and extracted data. Study-specific risk estimates were combined using random-effects model. Potential dose-response associations were explored with the use of generalized least-squares trend estimation.

RESULTS

21 studies were included in the meta-analysis. Higher dietary intakes of omega-3 PUFA was significantly associated with 14% (relative risk [RR]: 0.86, 95% confidence interval [CI]: 0.77, 0.96) and 29% (RR: 0.71, 95% CI: 0.55, 0.91) lower risk of early and late AMD, respectively. The dose-response analysis showed a 6% and 22% decrease in the risk of early and late AMD for each additional 1  g/d omega-3 PUFA intake. For individual omega-3 PUFA, the intake of eicosapentaenoic acid and docosahexaenoic acid was inversely associated with lower AMD risk, whereas no association was found for the alpha-linolenic acid. Consistent inverse associations were also found between fish intake and AMD. The pooled RRs comparing extreme categories of fish intake were 0.79 (95% CI: 0.70, 0.90) and 0.71 (95% CI: 0.60, 0.85) for early and late AMD risk, respectively. Every 15 g/d of fish consumption was associated with 13% and 14% lower early and late AMD. In addition, fish intake was associated with a significantly reduced risk of AMD progression (RR: 0.73, 95% CI: 0.53, 1.00).

CONCLUSIONS

A high intake of dietary omega-3 PUFA or fish was associated with a reduced risk of developing of AMD, which further supports that consumption of omega-3 PUFA-rich foods may be a new avenue nutritional approach to preventing AMD.

Association of Dietary Nutrient Intake with Early Age-Related Macular Degeneration in Japanese-Americans

Lifestyle factors may be associated with the development of age-related macular degeneration (AMD), in addition to demographic and genetic factors. The purpose of this cross-sectional study is to elucidate the association between nutrient intake and AMD in the Japanese-American population living in Los Angeles. We conducted a medical survey of Japanese immigrants and their descendants living in Los Angeles, including interviews on dietary habits, fundus photography, and physical examinations. Participants were classified into early AMD and control groups on the basis of fundus photographic findings. Consequently, among the 555 participants, 111 (20.0%) were diagnosed with early AMD. There were no late-stage AMD participants. Multivariate logistic regression analysis showed that the intake of animal fat and saturated fatty acids (SFA) was positively associated with early AMD (p for trend = 0.01 for animal fat, p for trend = 0.02 for SFA), and the intake of vegetable fat, total carbohydrate, simple carbohydrate, sugar, and fructose was inversely associated with early AMD (p for trend = 0.04 for vegetable fat, p for trend = 0.046 for carbohydrate, p for trend = 0.03 for simple carbohydrate, p for trend = 0.046 for sugar, p for trend = 0.02). Our findings suggest that excessive animal fat and SFA intake increases the risk for early AMD in Japanese-Americans whose lifestyles have been westernized.

Nano-scale resolution of native retinal rod disk membranes reveals differences in lipid composition

Photoreceptors rely on distinct membrane compartments to support their specialized function. Unlike protein localization, identification of critical differences in membrane content has not yet been expanded to lipids, due to the difficulty of isolating domain-specific samples. We have overcome this by using SMA to coimmunopurify membrane proteins and their native lipids from two regions of photoreceptor ROS disks. Each sample's copurified lipids were subjected to untargeted lipidomic and fatty acid analysis. Extensive differences between center (rhodopsin) and rim (ABCA4 and PRPH2/ROM1) samples included a lower PC to PE ratio and increased LC- and VLC-PUFAs in the center relative to the rim region, which was enriched in shorter, saturated FAs. The comparatively few differences between the two rim samples likely reflect specific protein-lipid interactions. High-resolution profiling of the ROS disk lipid composition gives new insights into how intricate membrane structure and protein activity are balanced within the ROS, and provides a model for future studies of other complex cellular structures.

Retinoid X receptor activation promotes photoreceptor survival and modulates the inflammatory response in a mouse model of retinitis pigmentosa

Photoreceptor cell (PHR) death is a hallmark of most retinal neurodegenerative diseases, in which inflammation plays a critical role. Activation of retinoid X receptors (RXR) modulates and integrates multiple cell functions, and has beneficial effects in animal models of chronic inflammatory diseases. Nonetheless, the mechanisms involved and their role in retina neuroprotection are poorly understood. In this work we assessed whether RXR activation prevents inflammation and/or PHR death in retinitis pigmentosa, an inherited retina neurodegeneration, using as an ex vivo model, retinas from the rd1 mice, a murine model of this disease. We demonstrated that rd1 retinas had lower levels of RXR alpha isoform than their wt counterparts at early developmental times, whereas its distribution pattern remained similar. In mixed neuro-glial cultures obtained from either rd1 or wt retinas, both PHR and Müller glial cells (MGC) expressed RXRalpha, and RXR activation by its synthetic pan-agonist PA024 selectively increased mRNA levels of RXRgamma isoform. PA024 decreased PHR death in rd1 mixed cultures; it reduced the amount of non-viable neurons, delayed the onset of PHR apoptosis, and decreased Bax mRNA levels. PA024 also reduced MGC reactivity in vitro before and at the onset of degeneration, decreasing GFAP expression, increasing glutamine synthetase mRNA levels, and promoting the transcription of the anti-inflammatory cytokine, Il-10. These results suggest that RXR activation rescues rd1 PHR and decreases MGC reactivity, promoting an anti-inflammatory environment in the rd1 retina, thus supporting the potential of RXR agonists as pharmacological tools for treating retina degenerative diseases.

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.

Low- and moderate-dose non-cancer effects of ionizing radiation in directly exposed individuals, especially circulatory and ocular diseases: a review of the epidemiology

PURPOSE

There are well-known correlations between high and moderate doses (>0.5 Gy) of ionizing radiation exposure and circulatory system damage, also between radiation and posterior subcapsular cataract. At lower dose correlations with circulatory disease are emerging in the Japanese atomic bomb survivors and in some occupationally exposed groups, and are still to some extent controversial. Heterogeneity in excess relative risks per unit dose in epidemiological studies at low (<0.1 Gy) and at low-moderate (>0.1 Gy, <0.5 Gy) doses may result from confounding and other types of bias, and effect modification by established risk factors. There is also accumulating evidence of excess cataract risks at lower dose and low dose rate in various cohorts. Other ocular endpoints, specifically glaucoma and macular degeneration have been little studied. In this paper, we review recent epidemiological findings, and also discuss some of the underlying radiobiology of these conditions. We briefly review some other types of mainly neurological nonmalignant disease in relation to radiation exposure.

CONCLUSIONS

We document statistically significant excess risk of the major types of circulatory disease, specifically ischemic heart disease and stroke, in moderate- or low-dose exposed groups, with some not altogether consistent evidence suggesting dose-response non-linearity, particularly for stroke. However, the patterns of risk reported are not straightforward. We also document evidence of excess risks at lower doses/dose-rates of posterior subcapsular and cortical cataract in the Chernobyl liquidators, US Radiologic Technologists and Russian Mayak nuclear workers, with fundamentally linear dose-response. Nuclear cataracts are less radiogenic. For other ocular endpoints, specifically glaucoma and macular degeneration there is very little evidence of effects at low doses; radiation-associated glaucoma has been documented only for doses >5 Gy, and so has the characteristics of a tissue reaction. There is some evidence of neurological detriment following low-moderate dose (∼0.1-0.2 Gy) radiation exposure in utero or in early childhood.

Dietary fatty acid intake, plasma fatty acid levels, and the risk of age-related macular degeneration (AMD): a dose-response meta-analysis of prospective cohort studies

PURPOSE

Previous population studies on the associations between dietary fatty acids (FAs), plasma FAs levels, and the risk of age-related macular degeneration (AMD) have yielded inconclusive results. Herein, we conducted a dose-response meta-analysis to quantitatively evaluate the associations between specific type of dietary FAs, plasma FAs on early and advanced AMD risk.

METHODS

PubMed, Web of Science, and EMBASE were systematically searched for observational cohort studies published through May 2020. For highest versus lowest comparison and dose-response analyses, the relative risk (RR) estimates with a 95% confidence interval (CI) were analyzed using random effects model.

RESULTS

11 studies with 167,581 participants were included in the meta-analysis. During the follow-up periods (ranging from 3 to 28 years), 6,318 cases of AMD were recorded. Dietary intake of docosahexaenoic acid (DHA) and eicosatetraenoic acid (EPA) combined (per 1 g/day increment) were found to be negatively associated with early AMD (RR: 0.67, 95% CI [0.51, 0.88]). Each 1 g/day increment of DHA (RR: 0.50, 95% CI [0.32, 0.78]) and EPA (RR: 0.40, 95% CI [0.18, 0.87]) was associated with a 50% and 60% reduction of early AMD risk, respectively. Plasma DHA (RR: 0.72, 95% CI [0.55, 0.95]) and EPA (RR: 0.57, 95% CI [0.40, 0.81]) indicated significant negative relationship with advanced AMD.

CONCLUSION

Increasing dietary intake of ω-3 polyunsaturated fatty acids (PUFAs), specifically DHA and EPA, were associated with a reduced risk of early subtype of AMD, while other types of FAs did not present significant results. Further research is warranted to explore the potential association between dietary FA, plasma FA levels, and advanced subtype of AMD.

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.

Protective Effects and Molecular Signaling of n-3 Fatty Acids on Oxidative Stress and Inflammation in Retinal Diseases

Oxidative stress and inflammation play crucial roles in the development and progression of retinal diseases. Retinal damage by various etiologies can result in retinopathy of prematurity (ROP), diabetic retinopathy (DR), and age-related macular degeneration (AMD). n-3 fatty acids are essential fatty acids and are necessary for homeostasis. They are important retinal membrane components and are involved in energy storage. n-3 fatty acids also have antioxidant and anti-inflammatory properties, and their suppressive effects against ROP, DR, and AMD have been previously evaluated. α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and their metabolites have been shown to alleviate retinal oxidative stress and inflammation involving various biological signaling pathways. In this review, we summarize the current understanding of the n-3 fatty acids effects on the mechanisms of these retinal diseases and how they exert their therapeutic effects, focusing on ALA, EPA, DHA, and their metabolites. This knowledge may provide new remedial strategies for n-3 fatty acids in the prevention and treatment of retinal diseases associated with oxidative stress and inflammation.

Oxidative stress as a therapeutic target for the prevention and treatment of early age-related macular degeneration

Age-related macular degeneration, the leading cause of irreversible visual loss among older adults in developed countries, is a chronic, multifactorial, and progressive disease with the development of painless, central vision loss. Retinal pigment epithelial cell dysfunction is a core change in age-related macular degeneration that results from aging and the accumulated effects of genetic and environmental factors that, in part, is both caused by and leads to oxidative stress. In this review, we describe the role of oxidative stress, the cytoprotective oxidative stress pathways, and the impact of oxidative stress on critical cellular processes involved in age-related macular degeneration pathobiology. We also offer targeted therapy that may define how antioxidant therapy can either prevent or improve specific stages of age-related macular degeneration.

Associations of the intestinal microbiome with the complement system in neovascular age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of severe vision loss in the aged population. The etiology of AMD is multifactorial including nutritional factors, genetic variants mainly in the complement pathway, environmental risk factors and alterations in the intestinal microbiome. However, it remains unexplored whether there is an interdependency of these factors leading to the development of AMD. To investigate this issue, a shotgun metagenomics analysis of 57 neovascular AMD and 58 healthy controls as well as of 16 complement C3-deficient mice and 16 wildtypes was performed. Whereas the class Negativicutes was more abundant in patients, the genus Oscillibacter and species Bacteroides had a significantly higher prevalence in persons without AMD. Similar taxonomic features were identified that distinguished wildtype mice from C3-deficient mice. Moreover, several purine signaling pathways were associated with both, neovascular AMD and C3 deficiency. While SNPs within the complement factor B gene were more abundant in controls, SNPs within the high temperature requirement A serine peptidase 1 and complement factor H (CFH) genes were associated with neovascular AMD. Using a classification model, Negativicutes was identified as a potential biomarker for AMD and furthermore, it positively correlated with CFH. This study suggests an association between the intestinal microbiome and the complement system in neovascular AMD.

Age-related Macular Degeneration: Nutrition, Genes and Deep Learning-The LXXVI Edward Jackson Memorial Lecture

PURPOSE

To evaluate the importance of nutritional supplements, dietary pattern, and genetic associations in age-related macular degeneration (AMD); and to discuss the technique of artificial intelligence/deep learning to potentially enhance research in detecting and classifying AMD.

DESIGN

Retrospective literature review.

METHODS

To review the studies of both prospective and retrospective (post hoc) analyses of nutrition, genetic variants, and deep learning in AMD in both the Age-Related Eye Disease Study (AREDS) and AREDS2.

RESULTS

In addition to demonstrating the beneficial effects of the AREDS and AREDS2 supplements of antioxidant vitamins and zinc (plus copper) for reducing the risk of progression to late AMD, these 2 studies also confirmed the importance of high adherence to Mediterranean diet in reducing progression of AMD in persons with varying severity of disease. In persons with the protective genetic alleles of complement factor H (CFH), the Mediterranean diet had further beneficial effect. However, despite the genetic association with AMD progression, prediction models found genetic information added little to the high predictive value of baseline severity of AMD for disease progression. The technique of deep learning, an arm of artificial intelligence, using color fundus photographs from AREDS/AREDS2 was superior in some cases and noninferior in others to clinical human grading (retinal specialists) and to the gold standard of the certified reading center graders.

CONCLUSIONS

Counseling individuals affected with AMD regarding the use of the AREDS2 supplements and the beneficial association of the Mediterranean diet is an important public health message. Although genetic testing is important in research, it is not recommended for prediction of disease or to guide therapies and/or dietary interventions in AMD. Techniques in deep learning hold great promise, but further prospective research is required to validate the use of this technique to provide improvement in accuracy and sensitivity/specificity in clinical research and medical management of patients with AMD.

Hypertension, antihypertensive medications use and risk of age-related macular degeneration in California Teachers Cohort

Sustained and inadequately controlled hypertension can promote the development of age-related macular degeneration (AMD) through multiple biologic pathways. Epidemiologic studies of high blood pressure, antihypertensive therapies, and the risk of AMD thus far have been inconclusive. However, few studies evaluated risks according to the use of different classes of antihypertensive drugs or took combinations of use into account. We performed a prospective cohort study by linking the California Teachers Study (CTS) cohort (N = 88 481) to statewide hospital discharge records up to December 31, 2012. History of high blood pressure, regular use of antihypertensive medications, and comprehensive risk factor information was collected via self-administered questionnaires at baseline in 1995-1996, and information on specific classes of antihypertensive drugs was provided by a subsample of CTS participants who completed a follow-up questionnaire in 2000. We identified 1762 female teachers with AMD during 14.8 years of follow-up on average. Applying Cox proportional hazard regression, we estimated increased risks of AMD among women treated for hypertension at baseline (HR = 1.15, 95% CI: 1.03, 1.30); the magnitude of the association increased with longer duration of antihypertensive treatment. In the subsample with more specific information on type of medication use, we estimated a 45% increased risk of AMD among women receiving diuretics as monotherapy compared to women with medications more potent than diuretics (HR = 1.45, 95% CI 1.10, 1.90). In women treated with a combination of antihypertensive drugs, we observed no increased risk of AMD for any individual class of drugs.

Diet patterns and the incidence of age-related macular degeneration in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss among the elderly.

OBJECTIVE

This study aimed to determine the association between dietary patterns and food groups (used to make them) with the 18-year incidence of AMD.

METHODS

ARIC (Atherosclerosis Risk in Communities) participants who showed change in AMD lesions between retinal photographs taken at visit 3 and visit 5 were graded side by side to determine incident AMD (any=144; early=117; late=27). A 66-line item food frequency questionnaire, administered at visit 1 and visit 3, was used to identify 29 food groups. Principal component analysis was used to derive dietary patterns from average food group servings. Logistic regression was used to estimate ORs and 95% CIs for incident AMD (any, early and late) by tertiles of dietary pattern scores, adjusted for age, race, education, total calories and smoking status. P-trend was estimated using continuous scores.

RESULTS

Western (unhealthy) and Prudent (healthy) dietary patterns were identified. No significant associations were observed between either dietary pattern and incident any or incident early AMD. However, a threefold higher incidence of late AMD was observed among participants with a Western pattern score above, as compared with below, the median (OR=3.44 (95% CI 1.33 to 8.87), p-trend=0.014). The risk of developing late AMD was decreased, but not statistically significant, among participants with a Prudent pattern score above, as compared with below, the median (OR=0.51 (95% CI 0.22 to 1.18), p-trend=0.054).

CONCLUSIONS

Diet patterns were not significantly associated with incident any or incident early AMD. However, consumption of a Western pattern diet may be a risk factor for development of late AMD.

Dietary Saturated Fatty Acid Intake and Early Age-Related Macular Degeneration in a Japanese Population

Purpose

To assess the association of dietary saturated fatty acid (SFA) intake with the presence of early AMD in a Japanese population.

Methods

The population-based Tsuruoka Metabolomics Cohort Study enrolled general population individuals aged 35 to 74 years from among participants in annual health check-up programs that included fundus photographs in Tsuruoka, Japan. A total of 4010 individuals participated in the baseline survey. After excluding nonresponders to a dietary survey and participants with suboptimal fundus image quality, 3988 participants (median age, 62.4 years) were included in this cross-sectional analysis. Dietary intake was assessed by a validated food frequency questionnaire. Fatty acids intake was adjusted for total energy intake by the residuals method. The association between fatty acid intake and presence of early AMD was assessed by logistic regression models.

Results

Median daily SFA intake was 11.3 g (interquartile range, 9.6, 13.0 g). After adjustments for potential confounding factors, participants in the highest quartile of SFA intake were less likely to have early AMD, compared with the lowest quartile (odds ratio, 0.71; 95% confidence interval: 0.52–0.96). A significant trend for decreased risk of early AMD with increasing SFA intake was noted (P = 0.011). There was no significant association between poly-unsaturated fatty acid (PUFA) including n3-PUFA intake and early AMD.

Conclusions

We found that increased SFA intake was associated with reduced risk of early AMD in a Japanese population with low SFA intake. Adequate fatty acid intake may be required to maintain retinal homeostasis and prevent AMD.

Benefits of micronutrient supplementation for reducing the risk of wet age-related macular disease and diabetic retinopathy

Age-related macular disease and diabetic retinopathy are chronic degenerative diseases characterised by progressive visual impairment. In Europe, age-related macular disease accounts for over 15% of blindness in adults over 50 years of age, and although the burden of diabetic retinopathy in terms of vision impairment is lower, vision loss associated with diabetic retinopathy is increasing with the rising prevalence of diabetes mellitus and the ageing of the population. Late-stage age-related macular disease can be subdivided into dry (non-neovascular) or wet (neovascular or exudative) forms. The large Age-Related Eye Disease Study 2 showed that supplementation with antioxidant nutrients reduces choroids neovascularisation and reduces the risk of progression of neovascular age-related macular disease. Antioxidant micronutrient supplements have also shown promising results in preventing the pathogenesis of retinopathy in animal models of diabetes. Age-related macular disease and diabetic retinopathy are understood to share some common pathophysiological characteristics, suggesting that micronutrients have an important role in ocular health in both conditions. This article will review the current evidence for the utility of micronutrients in preventing the development and progression of neovascular age-related macular disease and diabetic retinopathy.

Exploring Factors Underlying Ethnic Difference in Age-related Macular Degeneration Prevalence

AIMS

To assess contributions of dietary and genetic factors to ethnic differences in AMD prevalence.

DESIGN

Population-based analytical study.

METHODS

In the Blue Mountains Eye Study, Australia (European ancestry n = 2826) and Multi-Ethnic Cohort Study, Singapore (Asian ancestry, n = 1900), AMD was assessed from retinal photographs. Patterns of dietary composition and scores of the Alternative Healthy Eating Index were computed using food frequency questionnaire data. Genetic susceptibility to AMD was determined using either single nucleotide polymorphisms (SNPs) of the complement factor H and age-related maculopathy susceptibility 2 genes, or combined odds-weighted genetic risk scores of 24 AMD-associated SNPs. Associations of AMD with ethnicity, diet, and genetics were assessed using logistic regression. Six potential mediators covering genetic, diet and lifestyle factors were assessed for their contributions to AMD risk difference between the two samples using mediation analyses.

RESULTS

Age-standardized prevalence of any (early or late) AMD was higher in the European (16%) compared to Asian samples (9%, p < .01). Mean AMD-related genetic risk scores were also higher in European (33.3 ± 4.4) than Asian (Chinese) samples (31.7 ± 3.7, p < .001). In a model simultaneously adjusting for age, ethnicity, genetic susceptibility and Alternative Healthy Eating Index scores, only age and genetic susceptibility were significantly associated with AMD. Genetic risk scores contributed 19% of AMD risk difference between the two samples while intake of polyunsaturated fatty acids contributed 7.2%.

CONCLUSION

Genetic susceptibility to AMD was higher in European compared to Chinese samples and explained more of the AMD risk difference between the two samples than the dietary factors investigated.

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.

The association study of lipid metabolism gene polymorphisms with AMD identifies a protective role for APOE-E2 allele in the wet form in a Northern Spanish population

PURPOSE

To elucidate the potential role of eleven single nucleotide polymorphisms (SNPs) in the most relevant lipid metabolism genes in Northern Spanish patients with age-related macular degeneration (AMD).

METHODS

A case-control study of 228 unrelated native Northern Spanish patients diagnosed with AMD (73 dry and 155 wet) and 95 healthy controls was performed. DNA was isolated from peripheral blood and genotyped for the SNPs APOE rs429358 and rs7412; CTEP rs3764261; LIPC rs10468017 and rs493258; LPL rs12678919; ABCA1 rs1883025; ABCA4 rs76157638, rs3112831 and rs1800555; and SCARB1 rs5888, using TaqMan probes. An additional association study of ε2, ε3 and ε4 major isoforms of APOE gene with AMD has been carried out.

RESULTS

The allele and genotype frequencies for each of the eleven sequence variants in the lipid metabolism genes did not show significant differences when comparing AMD cases and controls. Statistical analysis revealed that APOE-ε2 carrier genotypes were less frequently observed in patients with wet AMD compared to controls (5.8% versus 13.7%, respectively: p = 3.28 × 10^-2 ; OR = 0.42, 95% CI: 0.19-0.95). The frequency of the allele T of rs10468017 (LIPC gene) was lower in dry AMD cases compared to controls (15.8 versus 27.9%, respectively: p = 8.4 × 10^-3 OR = 0.57, 95% CI: 0.33-0.98).

CONCLUSIONS

Our results suggest a protective role for APOE-ε2 allele to wet AMD in the Northern Spanish population.

Is dietary fat associated with the risk of age-related macular degeneration? Protocol for a systematic review and meta-analysis

Previous studies evaluating the association of dietary fat and risk of age-related macular degeneration (AMD) yield discrepant results. The objective of this systematic review (SR) and meta-analysis is to establish whether an association exists between dietary fat and AMD. This protocol was developed in line with the quality requirements of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) statement. PubMed and EMBASE will be searched for randomized controlled trials (RCTs), non-randomized trials (NRTs), cross-sectional studies, cohort studies, and case-control studies that evaluate the total incidence of AMD. The data extraction content and quantitative analysis will be carried out systematically. Newcastle-Ottawa Scale (NOS), the Cochrane risk of bias tool, and quality assessment tools will be used for quality assessment. This SR will synthesize evidence to determine if there is an association between dietary fat and AMD. The evidence would provide rationale for future research and serve as a basis for the development of future guidelines. Results are expected to be publicly available in mid 2020.PROSPERO registration number: CRD42019137086.

The Light and the Dark of Early and Intermediate AMD: Cone- and Rod-Mediated Changes Are Linked to Fundus Photograph and FAF Abnormalities

Purpose

The purpose of this paper is to describe the extent to which scotopic and photopic measures of visual function predict color fundus photograph (CFP) and fundus autofluorescence (FAF) changes in early and intermediate nonexudative AMD.

Methods

Sixty-nine observers were recruited: 56 AMD patients (mean age, 73 ± 12.98 years) and 13 controls (mean age, 67.77 ± 9.72 years). A nonmydriatic retinal camera was used to obtain stereo fundus photographs and FAF images were recorded with a cSLO Heidelberg Spectralis HRA+OCT. Visual acuity (VA) was measured using an Early Treatment of Diabetic Retinopathy Study chart. Contrast sensitivity (CS) was assessed with a Pelli-Robson chart. Dark adaptation (DA) curves were recorded at 3° eccentricity using a PC-based technique. Analysis of these curves yielded five parameters: cone threshold (CT), cone time constant (CC), cone-rod break (α), slope of the second rod component (S2), and rod-rod break (β).

Results

Both cone and rod sensitivity recovery were grossly abnormal in the patients. The rod recovery slope (S2) most accurately predicted the fundus photograph-based grade and the FAF classification (ρ = 0.61 and ρ = 0.60, respectively; both P < 0.0001). CS showed a strong association with FAF (ρ = 0.50, P < 0.0001) and with fundus photograph-based grade (ρ = 0.38, P < 0.002). There was no correlation between VA and either imaging method.

Conclusions

Dynamic, rod-based measures most accurately reflect the severity of early AMD. Although less specific to AMD than DA changes, static photopic abnormalities such as CS also correspond with morphologic changes. Assessment of function in early AMD should include dynamic rod- and cone-mediated measurements of sensitivity recovery.

Risk factors for progression of age-related macular degeneration

Purpose

Age‐related macular degeneration (AMD) is a degenerative disease of the macula, often leading to progressive vision loss. The rate of disease progression can vary among individuals and has been associated with multiple risk factors. In this review, we provide an overview of the current literature investigating phenotypic, demographic, environmental, genetic, and molecular risk factors, and propose the most consistently identified risk factors for disease progression in AMD based on these studies. Finally, we describe the potential use of these risk factors for personalised healthcare.

Recent findings

While phenotypic risk factors such as drusen and pigment abnormalities become more important to predict disease progression during the course of the disease, demographic, environmental, genetic and molecular risk factors are more valuable at earlier disease stages. Demographic and environmental risk factors such as age and smoking are consistently reported to be related to disease progression, while other factors such as sex, body mass index (BMI) and education are less often associated. Of all known AMD variants, variants that are most consistently reported with disease progression are rs10922109 and rs570618 in CFH, rs116503776 in C2/CFB/SKIV2L, rs3750846 in ARMS2/HTRA1 and rs2230199 in C3. However, it seems likely that other AMD variants also contribute to disease progression but to a lesser extent. Rare variants have probably a large effect on disease progression in highly affected families. Furthermore, current prediction models do not include molecular risk factors, while these factors can be measured accurately in the blood. Possible promising molecular risk factors are High‐Density Lipoprotein Cholesterol (HDL‐C), Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), zeaxanthin and lutein.

Summary

Phenotypic, demographic, environmental, genetic and molecular risk factors can be combined in prediction models to predict disease progression, but the selection of the proper risk factors for personalised risk prediction will differ among individuals and is dependent on their current disease stage. Future prediction models should include a wider set of genetic variants to determine the genetic risk more accurately, and rare variants should be taken into account in highly affected families. In addition, adding molecular factors in prediction models may lead to preventive strategies and personalised advice.

Higher Intake of Polyunsaturated Fatty Acid and Monounsaturated Fatty Acid is Inversely Associated With AMD

Purpose

To evaluate the association between dietary fat intake and the presence of AMD.

Methods

Cross-sectional, observational study with cohorts prospectively recruited from the United States and Portugal. AMD was diagnosed based on color fundus photographs with the AREDS classification. A validated food frequency questionnaire was used to calculate the percent energy intake of trans fat, saturated fat, monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA). Odds ratio (OR) and 95% confidence intervals for quintile of amount of FA were calculated. Multiple logistic regression was used to estimate the OR.

Results

We included 483 participants, 386 patients with AMD and 97 controls. Higher intake of trans fat was associated with a 2.3-fold higher odds of presence of AMD (P for trend = 0.0156), whereas a higher intake of PUFA (OR, 0.25; P for trend = 0.006) and MUFA (OR, 0.24; P for trend < 0.0001) presented an inverse association. Subgroup analysis showed that higher quintile of trans fat was associated with increased odds of having intermediate AMD (OR, 2.26; P for trend = 0.02); and higher quintile of PUFA and MUFA were inversely associated with intermediate AMD (OR, 0.2 [P for trend = 0.0013]; OR, 0.17 [P for trend < 0.0001]) and advanced AMD (OR, 0.13 [P for trend = 0.02]; OR, 0.26 [P for trend = 0.004]). Additionally, a statistically significant effect modification by country was noted with inverse association between MUFA and AMD being significant (OR, 0.04; P for trend < 0.0001) for the Portugal population only.

Conclusions

Our study shows that higher dietary intake of trans fat is associated with the presence of AMD, and a higher intake of PUFA and MUFA is inversely associated with 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.