Genetic analysis of simultaneous geographic atrophy and choroidal neovascularization

Prevalence of Geographic Atrophy in Advanced Age-Related Macular Degeneration (AMD) in Daily Practice

PURPOSE

To investigate the prevalence of geographic atrophy (GA) in advanced age-related macular degeneration (AMD) and the proportion of eyes that would meet the indication criteria for treatment with the first intravitreal anti-C3 agent (pegcetacoplan).

METHODS

This retrospective cross-sectional study included all AMD patients who visited the Macular-Retina-Centre Oberkassel in 2021. Eyes were classified according to AMD stages. Eyes with GA were divided into two groups regarding foveal involvement. Baseline factors were compared between eyes with foveal GA (FGA) and eyes with non-foveal GA (NFGA) to identify predictive factors for foveal involvement.

RESULTS

A total of 2033 eyes from 1027 patients were included. AMD stage was early in 296 (14.5%) cases, intermediate in 368 (18.1%) cases, and advanced in 1249 (61.4%) cases. A total of 1204 (60%) eyes had GA [932 (77%) FGA and 272 (23%) NFGA], while 125 eyes (27.4% from eyes with advanced dry AMD) met the indication criteria for treatment with intravitreal pegcetacoplan. The proportion of eyes with neovascular AMD was significantly higher in the FGA group compared to the NFGA group [598 (64.2%) vs. 152 (55.8%), p = 0.01].

CONCLUSIONS

At least a quarter of eyes with advanced AMD would be suitable for the upcoming intravitreal pegcetacoplan therapy. Foveal involvement of GA in advanced AMD seems to be more likely in neovascular AMD than in dry AMD.

Elastin turnover in ocular diseases: A special focus on age-related macular degeneration

The extracellular matrix (ECM) and its turnover play a crucial role in the pathogenesis of several inflammatory diseases, including age-related macular degeneration (AMD). Elastin, a critical protein component of the ECM, not only provides structural and mechanical support to tissues, but also mediates several intracellular and extracellular molecular signaling pathways. Abnormal turnover of elastin has pathological implications. In the eye elastin is a major structural component of Bruch's membrane (BrM), a critical ECM structure separating the retinal pigment epithelium (RPE) from the choriocapillaris. Reduced integrity of macular BrM elastin, increased serum levels of elastin-derived peptides (EDPs), and elevated elastin antibodies have been reported in AMD. Existing reports suggest that elastases, the elastin-degrading enzymes secreted by RPE, infiltrating macrophages or neutrophils could be involved in BrM elastin degradation, thus contributing to AMD pathogenesis. EDPs derived from elastin degradation can increase inflammatory and angiogenic responses in tissues, and the elastin antibodies are shown to play roles in immune cell activity and complement activation. This review summarizes our current understanding on the elastases/elastin fragments-mediated mechanisms of AMD pathogenesis.

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

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

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

Geographic atrophy (GA) and choroidal neovascularization (CNV), the two late forms of age-related macular degeneration, are generally considered two distinct entities. However, GA and CNV can occur simultaneously in the same eye, with GA usually occurring first. The prevalence of this combined entity is higher in histological studies than in clinical studies. No distinct systemic or genetic risk characteristics are associated with the combined GA/CNV entity, although on clinical examination and retinal imaging it can feature drusen or subretinal drusenoid deposits. GA and CNV may exist within the spectrum of a single disease, or they may be two very different diseases. Therapy with antivascular endothelial growth factor (anti-VEGF) is often successful for CNV, but some evidence suggests increased rates of GA development in eyes treated with anti-VEGF. In this article, we review the current literature regarding the epidemiology, clinical presentation, and treatment options for patients with the combined GA/CNV entity.

Pharmacogenetics and nutritional supplementation in age-related macular degeneration

The Age-Related Eye Disease Study (AREDS) recommended treatment with antioxidants plus zinc in patients with intermediate or advanced age-related macular degeneration in order to reduce progression risks. Recent pharmacogenetic studies have reported differences in treatment outcomes with respect to variants in genes for CFH and ARMS2, although the treatment recommendations based on these differences are controversial. Different retrospective analyses of subsets of patients from the same AREDS trial have drawn different conclusions. The practicing clinician, who is not an expert on genetics, clinical trial design, or statistical analysis, may be uncertain how to interpret these results. Based on the balance of the available literature, we suggest not changing established practice recommendations until additional evidence from clinical trials becomes available.

Risk characteristics of the combined geographic atrophy and choroidal neovascularisation phenotype in age-related macular degeneration

AIM

To investigate the risk characteristics of the combined geographic atrophy (GA) and choroidal neovascularisation (CNV) phenotype of age-related macular degeneration (AMD) compared to GA or CNV.

METHODS

Patients with advanced AMD were identified and divided into three groups using multimodal imaging: patients with GA in at least one eye, patients with CNV in at least one eye, and patients with simultaneous GA and CNV in at least one eye. Epidemiologic and clinical factors were gathered from patient questionnaires. Genotypes for age-related maculopathy susceptibility 2 (ARMS2) and complement factor H (CFH) were determined.

RESULTS

42 patients with GA or CNV, and 16 patients with combined GA/CNV were identified. Patients with the combined phenotype were older (86.4 vs 81.8 years, p=0.049), and had a higher prevalence of advanced AMD in the fellow eye (81.3% vs 31.0%, p<0.001). CFH and ARMS2 risk alleles were not associated with the combined phenotype.

CONCLUSIONS

The combined GA/CNV phenotype has similar epidemiologic, clinical, and genetic features as GA and CNV, but occurs at an older age and is more associated with advanced AMD in the fellow eye, suggesting that all these phenotypes are part of the same spectrum of disease and that the combined phenotype represents an even more advanced form of AMD than either GA or CNV.

1,25-Dihydroxyvitamin D decreases HTRA1 promoter activity in the rhesus monkey--a plausible explanation for the influence of vitamin D on age-related macular degeneration?

Age-related macular degeneration is the major cause of blindness in the elderly worldwide and the risk is influenced by both environmental and genetic risk factors. One important disease-associated region in humans is located on 10q26 and includes the two candidate genes ARMS2 and HTRA1. However, determination of the causative gene has not yet been possible and examining the situation in the rhesus monkey may help understand the situation in humans. In a recent paper, we characterized the rhesus monkey 10q26-orthologue region on chromosome 9 in detail and identified the drusen-associated HTRA1 promoter SNP rs196357513 as a putative risk factor. In this study, we predicted 9 binding sites for the vitamin D-dependent transcription factor vitamin D receptor in the rhesus HTRA1 promoter, one of which is destroyed by the rs196357513-risk allele. As patients with vitamin D deficit are at increased risk for age-related macular degeneration, a luciferase assay in transiently transfected ARPE19-cells was performed to evaluate the influence of the SNP rs196357513 and of 1,25-dihydroxyvitamin D on the rhesus monkey HTRA1 promoter activity. This revealed that the luciferase activity of the promoter construct containing the rs196357513 wild type allele was significantly reduced after vitamin D stimulation. An in silico analysis and literature search imply that this regulation could also play a role in human HTRA1 expression. Moreover, HTRA1 promoter activity of the construct containing the rs196357513 risk allele appeared diminished in comparison to the construct with the wild type allele, albeit this difference was not significant. The lower promoter activity due to the rhesus monkey rs196357513 risk allele apparently contradicts the common hypothesis for the human HTRA1 promoter risk allele of SNP rs11200638, for which a higher promoter activity has been observed. Our data point to a yet unexpected effect of decreased HTRA1 expression on drusen pathogenesis. Thus not only a higher HTRA1 expression, but an imbalance of HTRA1 might be disease-relevant. Both findings require closer analysis, but if relevance for humans proves true, it would impact current age-related macular degeneration research and treatment.