Genotype- and Phenotype-Based Subgroups in Geographic Atrophy Secondary to Age-Related Macular Degeneration: The EYE-RISK Consortium

Clinical Characteristics and Progression of Geographic Atrophy in a Japanese Population

PURPOSE

To elucidate the clinical characteristics and progression rate of geographic atrophy (GA) associated with age-related macular degeneration (AMD) in a Japanese population.

DESIGN

Retrospective, multicenter, observational study.

PARTICIPANTS

A total of 173 eyes from 173 patients from 6 university hospitals in Japan were included. Of 173 study eyes, 101 eyes from 101 patients were included in the follow-up group. All patients were Japanese, aged ≥ 50 years and had definite GA associated with AMD in at least 1 eye.

METHODS

The GA area was measured semiautomatically using fundus autofluorescence (FAF) images. In the follow-up group followed for > 6 months with FAF images, the GA progression rate was calculated by 2 methods: mm2 per year and mm per year using the square-root transformation (SQRT) strategy. Simple and multiple linear regression analyses were used to identify the baseline factors associated with the GA progression rate.

MAIN OUTCOME MEASURES

Clinical characteristics of GA and the GA progression rate.

RESULTS

The mean age was 76.8 ± 8.8 years, and 109 (63.0%) were males. Sixty-two (35.8%) patients had bilateral GA. The mean GA area was 3.06 ± 4.00 mm2 (1.44 ± 1.00 mm [SQRT]). Thirty-eight eyes (22.0%) were classified as having pachychoroid GA. Drusen and reticular pseudodrusen were detected in 115 (66.5%) and 73 (42.2%) eyes, respectively. The mean subfoveal choroidal thickness was 194.7 ± 105.5 μm. In the follow-up group (follow-up period: 46.2 ± 28.9 months), the mean GA progression rate was 1.01 ± 1.09 mm2 per year (0.23 ± 0.18 mm/year [SQRT]). In the multivariable analysis, the baseline GA area (SQRT; P = 0.002) and the presence of reticular pseudodrusen (P < 0.001) were significantly associated with a greater GA progression rate (SQRT).

CONCLUSIONS

Certain clinical characteristics of GA in Asian populations may differ from those in White populations. Asian patients with GA showed male dominance and relatively thicker choroid than White patients. There was a group with GA without drusen but with features of pachychoroid. The GA progression rate in this Asian population was relatively lower than that in White populations. Large GA and reticular pseudodrusen were associated with a greater GA progression rate.

FINANCIAL DISCLOSURE(S)

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

10q26 - The enigma in age-related macular degeneration

Despite comprehensive research efforts over the last decades, the pathomechanisms of age-related macular degeneration (AMD) remain far from being understood. Large-scale genome wide association studies (GWAS) were able to provide a defined set of genetic aberrations which contribute to disease risk, with the strongest contributors mapping to distinct regions on chromosome 1 and 10. While the chromosome 1 locus comprises factors of the complement system with well-known functions, the role of the 10q26-locus in AMD-pathophysiology remains enigmatic. 10q26 harbors a cluster of three functional genes, namely PLEKHA1, ARMS2 and HTRA1, with most of the AMD-associated genetic variants mapping to the latter two genes. High linkage disequilibrium between ARMS2 and HTRA1 has kept association studies from reliably defining the risk-causing gene for long and only very recently the genetic risk region has been narrowed to ARMS2, suggesting that this is the true AMD gene at this locus. However, genetic associations alone do not suffice to prove causality and one or more of the 14 SNPs on this haplotype may be involved in long-range control of gene expression, leaving HTRA1 and PLEKHA1 still suspects in the pathogenic pathway. Both, ARMS2 and HTRA1 have been linked to extracellular matrix homeostasis, yet their exact molecular function as well as their role in AMD pathogenesis remains to be uncovered. The transcriptional regulation of the 10q26 locus adds an additional level of complexity, given, that gene-regulatory as well as epigenetic alterations may influence expression levels from 10q26 in diseased individuals. Here, we provide a comprehensive overview on the 10q26 locus and its three gene products on various levels of biological complexity and discuss current and future research strategies to shed light on one of the remaining enigmatic spots in the AMD landscape.

Geographic Atrophy in Age-Related Macular Degeneration: A Tale of Two Stages

Purpose

To examine disease progression in age-related macular degeneration (AMD) at 2 distinct stages, progression to geographic atrophy (GA) versus GA expansion, by comparison of the risk and protective factors at each stage.

Design

Perspective.

Subjects

Individuals at risk of GA or with GA.

Main Outcome Measures

Progression to GA and GA expansion rate.

Methods

Critical synthesis of the literature on risk and protective factors, both environmental and genetic, for progression to GA versus GA expansion in AMD.

Results

Comparison of the risk and protective factors demonstrates partially overlapping but partially distinct risk and protective factors for progression to GA versus GA expansion. Some factors are shared (i.e., operating in the same direction at both stages), others are not shared, and others seem to operate in different directions at each stage. Risk variants at ARMS2/HTRA1 increase both risk of progression to GA and GA expansion rate, presumably through the same mechanism. By contrast, risk and protective variants at CFH/CFHR alter risk of GA but not GA expansion rate. A risk variant at C3 increases risk of GA but is associated with slower GA expansion. In environmental factors, cigarette smoking is associated with increased risk of GA and faster GA expansion, whereas increased age is associated with the former but not the latter. The Mediterranean diet is associated with decreased progression at both stages, although the food components with the largest contributions seem to differ between the 2 stages. Some phenotypic features, such as reticular pseudodrusen and hyperreflective foci, are associated with increased progression at both stages.

Conclusions

Analysis of the risk and protective factors for progression to GA and GA expansion demonstrates partially overlapping but partially distinct elements at each stage: some are shared, some are relevant to 1 stage only, and some even seem active in opposite directions at each stage. Aside from ARMS2/HTRA1, the overlap between the genetic risk factors for the 2 stages is minimal. This suggests that the biologic mechanisms differ at least partially between the 2 disease stages. This has implications for therapeutic approaches and suggests that treatment aimed at the underlying disease processes may need to be tailored by stage.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Two potentially distinct pathways to geographic atrophy in age-related macular degeneration characterized by quantitative fundus autofluorescence

BACKGROUND/AIMS

To demonstrate two distinct pathways to geographic atrophy (GA) that originate from soft drusen/ pigment epithelial detachments (PEDs) and subretinal drusenoid deposits (SDDs), respectively, and are characterized by their final quantitative autofluorescence (qAF) levels.

METHODS

23 eyes of 18 patients with GA underwent spectral-domain optical coherence tomography (SD-OCT) and qAF imaging on the qAF-ready Heidelberg Spectralis. 52 GA Regions-of-interest (ROIs), or clusters of adjacent lesions, were selected, and the ROIs were divided into groups by the dominant iAMD precursors on prior serial tracked SD-OCT scans. Mean qAF values and structural SD-OCT findings of groups were compared.

RESULTS

Group 1 lesions (soft drusen/PED precursors, 18/52) were isolated, with lower mean qAF (35.88 ± 12.75 units); group 3 lesions (SDD precursors, 12/52) were multilobular, with significantly higher mean qAF (71.62 ± 12.12 units, p < 0.05). Group 2 lesions, (mixed precursors, 22/52) had intermediate mean qAF (58.13 ± 67.92 units). Significantly greater prevalence of split RPE/ Bruch's membrane complex in SDD-associated GA, suggesting basal laminar deposit (BLamD), than in drusen-associated lesions was the major structural difference.

CONCLUSION

Quantitative autofluorescence (qAF) of GA lesions may reflect two distinct pathogenic pathways and structural outcomes, originating from soft drusen/PED and subretinal drusenoid deposits (SDDs), with the final qAF values lower or higher, respectively. Basal laminar deposit specifically in and adjacent to SDD-associated lesions may account for their greater autofluorescence. The potential importance of this paradigm is that it could direct, simplify and facilitate research on geographic atrophy by dividing the disease into two components that may be studied separately.

Systemic Metabolomics in a Framework of Genetics and Lifestyle in Age-Related Macular Degeneration

Insights into the pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness, point towards a complex interplay of genetic and lifestyle factors triggering various systemic pathways. This study aimed to characterize metabolomic profiles for AMD and to evaluate their position in the trias with genetics and lifestyle. This study included 5923 individuals from five European studies. Blood metabolomics were assessed using a nuclear magnetic resonance platform of 146 metabolites. Associations were studied using regression analyses. A genetic risk score (GRS) was calculated using β-values of 49 AMD variants, a lifestyle risk score (LRS) using smoking and diet data, and a metabolite risk score (MRS) using metabolite values. We identified 61 metabolites associated with early-intermediate AMD, of which 94% were lipid-related, with higher levels of HDL-subparticles and apolipoprotein-A1, and lower levels of VLDL-subparticles, triglycerides, and fatty acids (false discovery rate (FDR) p-value < 1.4 × 10^-2). Late AMD was associated with lower levels of the amino acids histidine, leucine, valine, tyrosine, and phenylalanine, and higher levels of the ketone bodies acetoacetate and 3-hydroxybutyrate (FDR p-value < 1.5 × 10^-3). A favorable lifestyle characterized by a healthy diet was associated with higher levels of amino acids and lower levels of ketone bodies, while an unfavorable lifestyle, including smoking, showed opposite effects (FDR p-value < 2.7 × 10^-2). The MRS mediated 5% of the effect of the GRS and 20% of that of the LRS on late AMD. Our findings show that metabolomic profiles differ between AMD stages and show that blood metabolites mostly reflect lifestyle. The severity-specific profiles spur further interest into the systemic effects related to disease conversion.

Methodological Appraisal of Phase 3 Clinical Trials in Geographic Atrophy

Geographic atrophy (GA) secondary to age-related macular degeneration is a common cause of blindness worldwide. Given the recent approval of the first therapy for GA, pegcetacoplan, we critically appraise methodological aspects of the phase 3 clinical trials published so far in this disease in relation to their design, analysis and interpretation. We reviewed some of the key attributes of all phase 3 clinical trials in GA available in the main public registry of clinical trials as of 20 May 2023. The topics discussed included types of endpoints, eligibility criteria, p-value and effect size, study power and sample size, the intention to treat principle, missing data, consistency of results, efficacy-safety balance and application of results. Five phase 3 clinical trials have reported results, either partially or completely: GATHER1, DERBY/OAKS, CHROMA/SPECTRI, SEATTLE and GATE. Although there are many similarities between these trials in terms of endpoints or broad eligibility criteria, they differ in several aspects (metric of the primary endpoint, sample size, type of adverse events, etc.) that can influence the results, which are discussed. Readers should understand key methodological aspects of clinical trials to improve their interpretation. On the other hand, authors should adhere to clinical trial reporting guidelines to communicate what was done and how it was done.

Reticular Pseudodrusen Status, ARMS2/HTRA1 Genotype, and Geographic Atrophy Enlargement: Age-Related Eye Disease Study 2 Report 32

PURPOSE

To determine whether reticular pseudodrusen (RPD) status, ARMS2/HTRA1 genotype, or both are associated with altered geographic atrophy (GA) enlargement rate and to analyze potential mediation of genetic effects by RPD status.

DESIGN

Post hoc analysis of an Age-Related Eye Disease Study 2 cohort.

PARTICIPANTS

Eyes with GA: n = 771 from 563 participants.

METHODS

Geographic atrophy area was measured from fundus photographs at annual visits. Reticular pseudodrusen presence was graded from fundus autofluorescence images. Mixed-model regression of square root of GA area was performed by RPD status, ARMS2 genotype, or both.

MAIN OUTCOME MEASURES

Change in square root of GA area.

RESULTS

Geographic atrophy enlargement was significantly faster in eyes with RPD (P < 0.0001): 0.379 mm/year (95% confidence interval [CI], 0.329-0.430 mm/year) versus 0.273 mm/year (95% CI, 0.256-0.289 mm/year). Enlargement was also significantly faster in individuals carrying ARMS2 risk alleles (P < 0.0001): 0.224 mm/year (95% CI, 0.198-0.250 mm/year), 0.287 mm/year (95% CI, 0.263-0.310 mm/year), and 0.307 mm/year (95% CI, 0.273-0.341 mm/year) for 0, 1, and 2, respectively. In mediation analysis, the direct effect of ARMS2 genotype was 0.074 mm/year (95% CI, 0.009-0.139 mm/year), whereas the indirect effect of ARMS2 genotype via RPD status was 0.002 mm/year (95% CI, -0.006 to 0.009 mm/year). In eyes with incident GA, RPD presence was not associated with an altered likelihood of central involvement (P = 0.29) or multifocality (P = 0.16) at incidence. In eyes with incident noncentral GA, RPD presence was associated with faster GA progression to the central macula (P = 0.009): 157 μm/year (95% CI, 126-188 μm/year) versus 111 μm/year (95% CI, 97-125 μm/year). Similar findings were observed in the Age-Related Eye Disease Study.

CONCLUSIONS

Geographic atrophy enlargement is faster in eyes with RPD and in individuals carrying ARMS2/HTRA1 risk alleles. However, RPD status does not mediate the association between ARMS2/HTRA1 genotype and faster enlargement. Reticular pseudodrusen presence and ARMS2/HTRA1 genotype are relatively independent risk factors, operating by distinct mechanisms. Reticular pseudodrusen presence does not predict central involvement or multifocality at GA incidence but is associated with faster progression toward the central macula. Reticular pseudodrusen status should be considered for improved predictions of enlargement rate.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

The Phenotypic Course of Age-Related Macular Degeneration for ARMS2/HTRA1: The EYE-RISK Consortium

PURPOSE

Age-related maculopathy susceptibility 2 (ARMS2) is considered the most enigmatic of the genes for age-related macular degeneration (AMD). We investigated the phenotypic course and spectrum of AMD for the risk haplotype at the ARMS2 and high-temperature requirement A serine peptidase 1 (HTRA1) locus in a large European consortium.

DESIGN

Pooled analysis of 4 case-control and 6 cohort studies.

PARTICIPANTS

Individuals (N = 17 204) aged 55 years or older participating in the European Eye Epidemiology consortium.

METHODS

Age-related macular degeneration features and macular thickness were determined on multimodal images; data on genetics and phenotype were harmonized. Risks of AMD features for rs3750486 genotypes at the ARMS2/HTRA1 locus were determined by logistic regression and were compared with a genetic risk score (GRS) of 19 variants at the complement pathway. Lifetime risks were estimated with Kaplan-Meier analyses in population-based cohorts.

MAIN OUTCOME MEASURES

Age-related macular degeneration features and stage.

RESULTS

Of 2068 individuals with late AMD, 64.7% carried the ARMS2/HTRA1 risk allele. For homozygous carriers, the odds ratio (OR) of geographic atrophy was 8.6 (95% confidence interval [CI], 6.5-11.4), of choroidal neovascularization (CNV) was 11.2 (95% CI, 9.4-13.3), and of mixed late AMD was 12.2 (95% CI, 7.3-20.6). Cumulative lifetime risk of late AMD ranged from 4.4% for carriers of the nonrisk genotype to 9.4% and 26.8% for heterozygous and homozygous carriers. The latter received the diagnosis of late AMD 9.6 years (95% CI, 8.0-11.2) earlier than carriers of the nonrisk genotype. The risk haplotype was not associated with hard or soft drusen < 125 μm (OR, 1.2; 95% CI, 0.9-1.7), but risks increased significantly for soft drusen ≥ 125 μm (OR, 2.1; 95% CI, 1.5-3.0), up to an OR of 7.2 (95% CI, 3.8-13.8) for reticular pseudodrusen. Compared with persons with a high GRS for complement, homozygous carriers of ARMS2/HTRA1 showed a higher risk of CNV (OR, 4.1; 95% CI, 3.2-5.4); risks of other characteristics were not different.

CONCLUSIONS

Carriers of the risk haplotype at ARMS2/HTRA1 have a particularly high risk of late AMD at a relatively early age. Data suggest that risk variants at ARMS2/HTRA1 act as a strong catalyst of progression once early signs are present. The phenotypic spectrum resembles that of complement genes, only with higher risks of CNV.

HODD: A Manually Curated Database of Human Ophthalmic Diseases with Symptom Characteristics and Genetic Variants Towards Facilitating Quick and Definite Diagnosis

Ophthalmic diseases are disorders that affect the eyes. Hundreds of causal genes and biological pathways have been reported to be closely correlated with ophthalmic diseases. However, these information are scattered across various resources, which has hindered a thorough and deep understanding of ophthalmic diseases. In the present work, we proposed the Human Ophthalmic Diseases Database (HODD), which currently deposits 730 ophthalmic diseases and 653 related genes and is available at http://bio-bigdata.cn/HODD/ . The disease-related information and genes related to ophthalmic diseases were collected from the several well-known databases. To comprehensively understand the ophthalmic diseases, the basic information was provided for each disease, including disease description, related genes, gene location, ocular and extraocular effect of the disease, protein-protein interaction and disease-associated pathways. All these data were reorganized and made accessible through multiple entrances. We hope that HODD will facilitate studies on ophthalmic diseases. The workflow for the construction of the HODD (Human Ophthalmic Diseases Database, http://bio-bigdata.cn/HODD/ ) database.

Progression of Age-Related Macular Degeneration Among Individuals Homozygous for Risk Alleles on Chromosome 1 (CFH-CFHR5) or Chromosome 10 (ARMS2/HTRA1) or Both

IMPORTANCE

Age-related macular degeneration (AMD) is a common cause of irreversible vision loss among individuals older than 50 years. Although considerable advances have been made in our understanding of AMD genetics, the differential effects of major associated loci on disease manifestation and progression may not be well characterized.

OBJECTIVE

To elucidate the specific associations of the 2 most common genetic risk loci for AMD, the CFH-CFHR5 locus on chromosome 1q32 (Chr1) and the ARMS2/HTRA1 locus on chromosome 10q26 (Chr10)-independent of one another and in combination-with time to conversion to late-stage disease and to visual acuity loss.

DESIGN, SETTING, AND PARTICIPANTS

This case series study included 502 individuals who were homozygous for risk variants at both Chr1 and Chr10 (termed Chr1&10-risk) or at either Chr1 (Chr1-risk) or Chr10 (Chr10-risk) and who had enrolled in Genetic and Molecular Studies of Eye Diseases at the Sharon Eccles Steele Center for Translational Medicine between September 2009 and March 2020. Multimodal imaging data were reviewed for AMD staging, including grading of incomplete and complete retinal pigment epithelium and outer retinal atrophy.

MAIN OUTCOMES AND MEASURES

Hazard ratios and survival times for conversion to any late-stage AMD, atrophic or neovascular, and associated vision loss of 2 or more lines.

RESULTS

In total, 317 participants in the Chr1-risk group (median [IQR] age at first visit, 75.6 [69.5-81.7] years; 193 women [60.9%]), 93 participants in the Chr10-risk group (median [IQR] age at first visit, 77.5 [72.2-84.2] years; 62 women [66.7%]), and 92 participants in the Chr1&10-risk group (median [IQR] age at first visit, 71.7 [68.0-76.3] years; 62 women [67.4%]) were included in the analyses. After adjusting for age and AMD grade at first visit, compared with 257 participants in the Chr1-risk group, 56 participants in the Chr1&10-risk group (factor of 3.3 [95% CI, 1.6-6.8]; P < .001) and 58 participants in the Chr10-risk group (factor of 2.6 [95% CI, 1.3-5.2]; P = .007) were more likely to convert to a late-stage phenotype during follow-up. This difference was mostly associated with conversion to macular neovascularization, which occurred earlier in participants with Chr1&10-risk and Chr10-risk. Eyes in the Chr1&10-risk group (median [IQR] survival, 5.7 [2.1-11.1] years) were 2.1 (95% CI, 1.1-3.9; P = .03) times as likely and eyes in the Chr10-risk group (median [IQR] survival, 6.3 [2.7-11.3] years) were 1.8 (95% CI, 1.0-3.1; P = .05) times as likely to experience a visual acuity loss of 2 or more lines compared with eyes of the Chr1-risk group (median [IQR] survival, 9.4 [4.1-* (asterisk indicates event rate did not reach 75%)] years).

CONCLUSIONS AND RELEVANCE

These findings suggest differential associations of the 2 major AMD-related risk loci with structural and functional disease progression and suggest distinct underlying biological mechanisms associated with these 2 loci. These genotype-phenotype associations may warrant consideration when designing and interpreting AMD research studies and clinical trials.

Dry age-related macular degeneration in the Japanese population

PURPOSE

To elucidate the clinical characteristics of eyes with dry age-related macular degeneration (AMD) in Japan.

STUDY DESIGN

Retrospective.

METHODS

We performed a nationwide survey of dry AMD. A questionnaire on dry AMD was sent to 3,801 major hospitals and eye clinics nationwide. Whenever both eyes met the diagnostic criteria, only the eye with more advanced geographic atrophy was included.

RESULTS

In the current survey, 81 patients (81 eyes) with dry AMD were included. Of the 81 patients, 56 (69.1%) were men, and the mean age of the patients was 76.6 ± 8.4 (range, 54-94) years. Twenty-four patients (29.6%) had a history of smoking. The decimal best corrected-visual acuity (BCVA) was equal to or better than 0.7 in 25 eyes (30.9%), but worse than 0.1 in 17 eyes (21.0%). The mean BCVA was 0.62 ± 0.59 in logarithm of the minimum angle of resolution. Lesion size (the greatest linear dimension of the largest geographic atrophy) was ≥ 2 disc diameter in 33 eyes (40.7%) and < 1 disc diameter in 21 eyes (25.9%). Soft drusen was observed in 27 eyes (33.3%), and reticular pseudodrusen was observed in 31 eyes (38.3%). Of the 81 patients, the other eye was diagnosed as dry AMD in 26 eyes (32.1%), neovascular AMD in 16 eyes (19.8%), and intermediate AMD in 18 eyes (22.2%).

CONCLUSION

Dry AMD in the Japanese population has characteristics of male predominance, older age, high prevalence of reticular pseudodrusen, and high bilaterality.

mTOR Inhibition via Rapamycin Treatment Partially Reverts the Deficit in Energy Metabolism Caused by FH Loss in RPE Cells

Age-related macular degeneration (AMD) is a complex degenerative disease of the retina with multiple risk-modifying factors, including aging, genetics, and lifestyle choices. The combination of these factors leads to oxidative stress, inflammation, and metabolic failure in the retinal pigment epithelium (RPE) with subsequent degeneration of photoreceptors in the retina. The alternative complement pathway is tightly linked to AMD. In particular, the genetic variant in the complement factor H gene (CFH), which leads to the Y402H polymorphism in the factor H protein (FH), confers the second highest risk for the development and progression of AMD. Although the association between the FH Y402H variant and increased complement system activation is known, recent studies have uncovered novel FH functions not tied to this activity and highlighted functional relevance for intracellular FH. In our previous studies, we show that loss of CFH expression in RPE cells causes profound disturbances in cellular metabolism, increases the vulnerability towards oxidative stress, and modulates the activation of pro-inflammatory signaling pathways, most importantly the NF-kB pathway. Here, we silenced CFH in hTERT-RPE1 cells to investigate the mechanism by which intracellular FH regulates RPE cell homeostasis. We found that silencing of CFH results in hyperactivation of mTOR signaling along with decreased mitochondrial respiration and that mTOR inhibition via rapamycin can partially rescue these metabolic defects. To obtain mechanistic insight into the function of intracellular FH in hTERT-RPE1 cells, we analyzed the interactome of FH via immunoprecipitation followed by mass spectrometry-based analysis. We found that FH interacts with essential components of the ubiquitin-proteasomal pathway (UPS) as well as with factors associated with RB1/E2F signalling in a complement-pathway independent manner. Moreover, we found that FH silencing affects mRNA levels of the E3 Ubiquitin-Protein Ligase Parkin and PTEN induced putative kinase (Pink1), both of which are associated with UPS. As inhibition of mTORC1 was previously shown to result in increased overall protein degradation via UPS and as FH mRNA and protein levels were shown to be affected by inhibition of UPS, our data stress a potential regulatory link between endogenous FH activity and the UPS.

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.

Seeing Beyond Anatomy: Quality of Life with Geographic Atrophy

Quality of life (QoL) is a complex idea without a clear consensus definition. Generally speaking, QoL refers to several subjective measures of wellbeing that vary by individual and circumstance. QoL can decline noticeably as a disease progresses. This is particularly true for geographic atrophy (GA), an advanced form of age-related macular degeneration. GA leads to vision loss for which there is no currently approved pharmacological treatment. There is a lack of qualitative, patient-driven research on QoL in GA. There is also limited information available to both patients and physicians about GA, existing support groups and available assistive technologies. To address this, we have collated the experiences of a person with GA and those of her partner and carer with the current literature on QoL in GA. We have also outlined some of the wide range of developing technologies available to help people with GA carry out daily tasks and hobbies. It is clear that support, whether through informal or structured care, is vital to the wellbeing of people with GA. Despite this, the general public are often unaware of care work, which may result in this integral role being undervalued and under acknowledged. Furthermore, it is apparent that the general public have fundamental misunderstandings around what vision loss entails and are unaware that blindness is a vast spectrum. This feeds into the seemingly paradoxical mix of isolation and dependence on others that often results from GA and vision loss. Through this qualitative examination of a patient's experiences, we hope to inform and educate both patients and physicians about GA as well as precipitate discussion around the frameworks that should be in place to support both newly diagnosed and long-term patients with GA and other retinal diseases. Seeing beyond anatomy: quality of life with geographic atrophy (WMV 29479 kb).

Cluster analysis and genotype-phenotype assessment of geographic atrophy in age-related macular degeneration: AREDS2 Report 25

PURPOSE

To explore whether phenotypes in geographic atrophy (GA) secondary to age-related macular degeneration (AMD) can be separable into two or more partially distinct subtypes and if these have different genetic associations. This is important since the discovery of distinct GA subtypes associated with different genetic factors might require customized therapeutic approaches.

DESIGN

Cluster analysis of participants within a controlled clinical trial, followed by assessment of phenotype-genotype associations.

PARTICIPANTS

AREDS2 participants with incident GA during study follow-up: 598 eyes of 598 participants (median age 75.7y).

METHODS

Phenotypic features from reading center grading of fundus photographs were subjected to cluster analysis, by both k-means and hierarchical methods, in cross-sectional analyses (using 15 phenotypic features assessed principally at GA emergence) and longitudinal analyses (using 14 phenotypic features). In pre-specified hypothesis tests, identified clusters were compared by four pathway-based genetic risk scores (complement, extracellular matrix, lipid, and ARMS2). The analyses were repeated in reverse, i.e., clustering by genotype and comparison by phenotype.

MAIN OUTCOME MEASURES

Characteristics and quality of cluster solutions, assessed by Calinski-Harabasz scores, unexplained variance, and consistency; genotype-phenotype associations, assessed by t test.

RESULTS

In cross-sectional phenotypic analyses, k-means identified two clusters (labeled A, B), while hierarchical clustering identified four (C-F); A-E membership differed principally by GA configuration but in relatively few other ways. In longitudinal phenotypic analyses, k-means identified two clusters (G, H), which differed principally by smoking status but in relatively few other ways. These three sets of cluster divisions were not similar to each other (r ≤ 0.20). Despite adequate power, pairwise cluster comparison by the four genetic risk scores demonstrated no significant differences (p>0.05 for all). In clustering by genotype, k-means identified two clusters (I/J). These differed principally at ARMS2, but no significant genotype-phenotype associations were observed (p>0.05 for all).

CONCLUSIONS

Phenotypic clustering resulted in GA subtypes defined principally by GA configuration in cross-sectional analyses, but these were not replicated in longitudinal analyses. These negative findings, together with the absence of significant phenotype-genotype associations, indicate that GA phenotypes may vary continuously across a spectrum, rather than consisting of distinct subtypes that arise from separate genetic etiologies.

Geographic atrophy: where we are now and where we are going

PURPOSE OF REVIEW

Age-related macular degeneration (AMD) affects a significant percentage of the elderly population and end-stage disease classified by either geographic atrophy (GA) or neovascular AMD (nvAMD) is one of the leading causes of vision loss worldwide. Despite the fact that there are currently treatments for nvAMD, there are no treatments in practice to prevent disease onset or progression of GA. This topic is at the forefront of ophthalmic research demonstrated by the recent advances in disease characterization, genetic and environmental risk factor classification, biomarker discovery and mechanism of pathogenesis categorization. There are also numerous clinical treatment trials underway, targeting proposed pathways and biomarkers associated with GA that are promising.

RECENT FINDINGS

With several clinical trials of potential treatments underway and numerous recent publications on disease diagnosis and classification, the understanding of GA pathogenesis has increased substantially. Although the exact mechanism of pathology is still elusive, recent literature has highlighted the utilization of current and new ophthalmic imaging modalities and discovery of objective and functional markers that can lead to earlier diagnosis and treatment.

SUMMARY

Herein, we will provide an overview and discussion of the current status of GA including advances in mechanism of pathogenesis, diagnosis, classification and current treatment modalities.

Mitochondria-dependent phase separation of disease-relevant proteins drives pathological features of age-related macular degeneration

Age-related macular degeneration (AMD) damages the retinal pigment epithelium (RPE), the tissue that safeguards photoreceptor health, leading to irreversible vision loss. Polymorphisms in cholesterol and complement genes are implicated in AMD, yet mechanisms linking risk variants to RPE injury remain unclear. We sought to determine how allelic variants in the apolipoprotein E cholesterol transporter modulate RPE homeostasis and function. Using live-cell imaging, we show that inefficient cholesterol transport by the AMD risk-associated ApoE2 increases RPE ceramide, leading to autophagic defects and complement-mediated mitochondrial damage. Mitochondrial injury drives redox state–sensitive cysteine-mediated phase separation of ApoE2, forming biomolecular condensates that could nucleate drusen. The protective ApoE4 isoform lacks these cysteines and is resistant to phase separation and condensate formation. In Abca^–/– Stargardt macular degeneration mice, mitochondrial dysfunction induces liquid-liquid phase separation of p62/SQSTM1, a multifunctional protein that regulates autophagy. Drugs that decrease RPE cholesterol or ceramide prevent mitochondrial injury and phase separation in vitro and in vivo. In AMD donor RPE, mitochondrial fragmentation correlates with ApoE and p62 condensates. Our studies demonstrate that major AMD genetic and biological risk pathways converge upon RPE mitochondria, and identify mitochondrial stress-mediated protein phase separation as an important pathogenic mechanism and promising therapeutic target in AMD.

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.