A Revised Hemodynamic Theory of Age-Related Macular Degeneration

The impact of NF-κB on inflammatory and angiogenic processes in age-related macular degeneration

Age-related macular degeneration (AMD) is a prominent cause of vision loss, characterized by two different types, dry (atrophic) and wet (neovascular). Dry AMD is distinguished by the progressive deterioration of retinal cells, which ultimately causes a decline in vision. In contrast, wet AMD is defined by the abnormal development of blood vessels underneath the retina, leading to a sudden and severe vision impairment. The course of AMD is primarily driven by chronic inflammation and pathological angiogenesis, in which the NF-κB signaling pathway plays a crucial role. The activation of NF-κB results in the generation of pro-inflammatory cytokines, chemokines, and angiogenic factors like VEGF, which contribute to inflammation and the formation of new blood vessels in AMD. This review analyzes the intricate relationship between NF-κB signaling, inflammation, and angiogenesis in AMD and assesses the possibility of using NF-κB as a target for therapy. The evaluation involves a comprehensive examination of preclinical and clinical evidence that substantiates the effectiveness of NF-κB inhibitors in treating AMD by diminishing inflammation and pathological angiogenesis.

Aging of the eye: Lessons from cataracts and age-related macular degeneration

Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease.

Evaluation of choroid vascular layer thickness in wet age-related macular degeneration using artificial intelligence

PURPOSE

To facilitate the assessment of choroid vascular layer thickness in patients with wet age-related macular degeneration (AMD) using artificial intelligence (AI).

METHODS

We included 194 patients with wet AMD and 225 healthy participants. Choroid images were obtained using swept-source optical coherence tomography. The average Sattler layer-choriocapillaris complex thickness (SLCCT), Haller layer thickness (HLT), and choroidal thickness (CT) were auto-measured at 7 regions centered around the foveola using AI and subsequently compared between the 2 groups.

RESULTS

The SLCCT was lower in the AMD group than in the control group (P < 0.05). The HLT was significantly higher in the AMD group than in the control group at the Tparafovea and T-perifovea in the total population (P < 0.05) and in the ≤70-year subgroup (P < 0.05). The CT was higher in the AMD group than in the control group, particularly at the N-perifovea, T-perifovea, and T-parafovea in the ≤70-year subgroup; Interestingly, it was lower in the AMD group than in the control group at the Nparafovea, N-fovea, foveola, and T-fovea in the >70-year subgroup (P < 0.05).

CONCLUSION

This novel AI-based auto-measurement was more accurate, efficient, and detailed than manual measurements. SLCCT thinning was observed in wet AMD; however, CT changes depended on the interaction between HLT compensatory thickening and SLCCT thinning.

Understanding the Impact of the Sirtuin 1 (SIRT1) Gene on Age-related Macular Degeneration: A Comprehensive Study

Age-related macular degeneration (AMD) is a prevalent and incurable condition affecting the central retina and posing a significant risk to vision, particularly in individuals over the age of 60. As the global population ages, the prevalence of AMD is expected to rise, leading to substantial socioeconomic impacts and increased healthcare costs. The disease manifests primarily in two forms, neovascular and non-neovascular, with genetic, environmental and lifestyle factors playing a pivotal role in disease susceptibility and progression. This review article involved conducting an extensive search across various databases, including Google Scholar, PubMed, Web of Science, ScienceDirect, Scopus and EMBASE, to compile relevant case-control studies and literature reviews from online published articles extracted using search terms related to the work. SIRT1, a key member of the sirtuin family, influences cellular processes such as ageing, metabolism, DNA repair and stress response. Its dysregulation is linked to retinal ageing and ocular conditions like AMD. This review discusses the role of SIRT1 in AMD pathology, its association with genetic variants and its potential as a biomarker, paving the way for targeted interventions and personalised treatment strategies. In addition, it highlights the findings of case-control studies investigating the relationship between SIRT1 gene polymorphisms and AMD risk. These studies collectively revealed a significant association between certain SIRT1 gene variants and AMD risk. Further studies with larger sample sizes are required to validate these findings. As the prevalence of AMD grows, understanding the role of SIRT1 and other biomarkers becomes increasingly vital for improving diagnosis, treatment and, ultimately, patient outcomes.

Effects of donor-specific microvascular anatomy on hemodynamic perfusion in human choriocapillaris

Evidence from histopathology and clinical imaging suggest that choroidal anatomy and hemodynamic perfusion are among the earliest changes in retinal diseases such as age-related macular degeneration (AMD). However, how inner choroidal anatomy affects hemodynamic perfusion is not well understood. Therefore, we sought to understand the influences of choroidal microvascular architecture on the spatial distribution of hemodynamic parameters in choriocapillaris from human donor eyes using image-based computational hemodynamic (ICH) simulations. We subjected image-based inner choroid reconstructions from eight human donor eyes to ICH simulation using a kinetic-based volumetric lattice Boltzmann method to compute hemodynamic distributions of velocity, pressure, and endothelial shear stress. Here, we demonstrate that anatomic parameters, including arteriolar and venular arrangements and intercapillary pillar density and distribution exert profound influences on inner choroidal hemodynamic characteristics. Reductions in capillary, arteriolar, and venular density not only reduce the overall blood velocity within choriocapillaris, but also substantially increase its spatial heterogeneity. These first-ever findings improve understanding of how choroidal anatomy affects hemodynamics and may contribute to pathogenesis of retinal diseases such as AMD.

Biomarkers for the Progression of Intermediate Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of severe vision loss worldwide, with a global prevalence that is predicted to substantially increase. Identifying early biomarkers indicative of progression risk will improve our ability to assess which patients are at greatest risk of progressing from intermediate AMD (iAMD) to vision-threatening late-stage AMD. This is key to ensuring individualized management and timely intervention before substantial structural damage. Some structural biomarkers suggestive of AMD progression risk are well established, such as changes seen on color fundus photography and more recently optical coherence tomography (drusen volume, pigmentary abnormalities). Emerging biomarkers identified through multimodal imaging, including reticular pseudodrusen, hyperreflective foci, and drusen sub-phenotypes, are being intensively explored as risk factors for progression towards late-stage disease. Other structural biomarkers merit further research, such as ellipsoid zone reflectivity and choriocapillaris flow features. The measures of visual function that best detect change in iAMD and correlate with risk of progression remain under intense investigation, with tests such as dark adaptometry and cone-specific contrast tests being explored. Evidence on blood and plasma markers is preliminary, but there are indications that changes in levels of C-reactive protein and high-density lipoprotein cholesterol may be used to stratify patients and predict risk. With further research, some of these biomarkers may be used to monitor progression. Emerging artificial intelligence methods may help evaluate and validate these biomarkers; however, until we have large and well-curated longitudinal data sets, using artificial intelligence effectively to inform clinical trial design and detect outcomes will remain challenging. This is an exciting area of intense research, and further work is needed to establish the most promising biomarkers for disease progression and their use in clinical care and future trials. Ultimately, a multimodal approach may yield the most accurate means of monitoring and predicting future progression towards vision-threatening, late-stage AMD.

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.

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.

Suppression of Age-Related Macular Degeneration-like Pathology by c-Jun N-Terminal Kinase Inhibitor IQ-1S

Age-related macular degeneration (AMD) is the leading cause of irreversible visual impairment worldwide. The development of AMD is associated with inflammation, oxidative stress, and progressive proteostasis imbalance, in the regulation of which c-Jun N-terminal kinases (JNK) play a crucial role. JNK inhibition is discussed as an alternative way for prevention and treatment of AMD and other neurodegenerative diseases. Here we assess the retinoprotective potential of the recently synthesized JNK inhibitor 11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S) using senescence-accelerated OXYS rats as a model of AMD. The treatment with IQ-1S (50 mg/kg body weight intragastric) during the period of active disease development (from 4.5 to 6 months of age) improved some (but not all) histological abnormalities associated with retinopathy. IQ-1S improved blood circulation, increased the functional activity of the retinal pigment epithelium, reduced the VEGF expression in the endothelial cells, and increased the expression of PEDF in the neuroretina. The result was a decrease in the degeneration of photoreceptors and neurons of the inner layers. IQ-1S significantly improved the retinal ultrastructure and increased the number of mitochondria, which were significantly reduced in the neuroretina of OXYS rats compared to Wistar rats. It seems probable that using IQ-1S can be a good prophylactic strategy to treat AMD.

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.

Current Views on Chr10q26 Contribution to Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the global aging population. Familial aggregation and genome-wide association (GWA) studies have identified gene variants associated with AMD, implying a strong genetic contribution to AMD development. Two loci, on human Chr 1q31 and 10q26, respectively, represent the most influential of all genetic factors. While the role of CFH at Chr 1q31 is well established, uncertainty remains about the genes ARMS2 and HTRA1, at the Chr 10q26 locus. Since both genes are in strong linkage disequilibrium, assigning individual gene effects is difficult. In this chapter, we review current literature about ARMS2 and HTRA1 and their relevance to AMD risk. Future studies will be necessary to unravel the mechanisms by which they contribute to AMD.

Investigations of Renal Function and Age-Related Macular Degeneration Phenotypes

PURPOSE

To investigate potential associations between renal function and age-related macular degeneration (AMD) features as assessed with multimodal retinal imaging.

METHODS

A subset of participants included in a dark adaptation study with varying AMD severities had estimated glomerular filtration rate (eGFR) values (mL/min/1.73 m2) obtained from renal function laboratory testing of serum creatinine and cystatin C. Multimodal imaging from visit dates associated with serum samples was graded by the Wisconsin Reading Center for AMD features. Associations of eGFR with AMD features and severity grades, age, smoker status and rod-intercept time were investigated. Simple univariate analyses, age-corrected multivariate analyses, and a feature-selecting least absolute shrinkage and selection operator regression were performed for eGFR as a continuous dependent variable.

RESULTS

A total of 110 patients (mean age, 75.1 ± 9.4 years; mean eGFR, 70.7 ± 18.2 mL/min/1.73 m2) were included. In univariate analyses age (estimate, -1.16 units/year; 95% confidence interval [CI], -1.46 to -0.87; P < 0.0001), rod-intercept time (estimate, -0.54 units/minute; 95% CI, -0.81 to -0.27; P < 0.001) and subretinal drusenoid deposits (-11.12 units for subretinal drusenoid deposit presence in either eye; 95% CI, -20.23 to -2.01; P = 0.017) were associated with decreased renal function. However, in age-corrected multivariate models, age was the only significant variable associated with renal function, confirmed by least absolute shrinkage and selection operator regression.

CONCLUSIONS

Accounting for age, renal function parameters did not show an association with AMD features.

TRANSLATIONAL RELEVANCE

Bruch's membrane of the eye and the glomerular basement membrane of the kidney share physiologic similarities such that decreased renal function may demonstrate associations with AMD phenotypes.

Adherence to a Mediterranean Diet and Geographic Atrophy Enlargement Rate: Age-Related Eye Disease Study 2 Report 29

PURPOSE

To determine whether closer adherence to a Mediterranean diet was associated with altered speed of geographic atrophy (GA) enlargement.

DESIGN

Post hoc analysis of a cohort within the Age-Related Eye Disease Study 2.

PARTICIPANTS

The study included 1155 eyes (850 participants; mean age, 74.9 years) with GA at 2 or more visits.

METHODS

Geographic atrophy area was measured from color fundus photographs at annual visits. An alternative Mediterranean Diet index (aMedi) was calculated for each participant by food frequency questionnaire. Mixed-model regression of square root GA area was performed by aMedi.

MAIN OUTCOME MEASURES

Change in square root of GA area over time.

RESULTS

Over a mean follow-up of 3.1 years, the mean GA enlargement rate was 0.282 mm/year (95% confidence interval, 0.270-0.293). Enlargement was significantly slower in those with higher aMedi at 0.256 mm/year (0.236-0.276), 0.290 (0.268-0.311), and 0.298 (0.280-0.317; P = 0.008) for aMedi tertiles 3, 2, and 1, respectively. Of the 9 aMedi components considered separately, significant differences in enlargement rate were observed for 4 (whole fruit [P = 0.0004], red meat [P = 0.0002], alcohol [P = 0.006], and monounsaturated fatty acid to saturated fatty acid ratio ([MUFA:SFA] [P = 0.040]) but not for fish (P = 0.14). Enlargement was slower in those with higher whole fruit, lower red meat, moderate alcohol, and higher MUFA:SFA intake. In the 768 eyes with noncentral GA, aMedi was not associated with slower progression to central involvement: hazard ratios were 1.11 (0.83-1.48) and 0.95 (0.71-1.26) for tertiles 2 and 3, respectively.

CONCLUSIONS

A Mediterranean-type diet was associated with slower GA enlargement. Diet patterns like this may therefore lead to clinically meaningful delays in vision loss. Several components seemed to contribute most to this association in a pattern that differed from those most associated with decreased progression to GA. Hence, the Mediterranean diet is associated with protection against both faster progression to GA and faster enlargement of GA but for partially distinct reasons. These findings may help inform evidence-based dietary recommendations. Understanding the mechanisms responsible may provide insights into the underlying biology and lead to the development of nutritional supplements.

Pathophysiology of Age-Related Macular Degeneration: Implications for Treatment

Age-related macular degeneration (AMD) is a complex, multifactorial, progressive retinal disease that affects millions of people worldwide and has become the leading cause of visual impairment in developed countries. The disease etiopathogenesis is not understood fully, although many triggers and processes that lead to dysfunction and degeneration of the retinal pigment epithelium (RPE) have already been identified. Thus, the lack of cellular control of oxidative stress, altered proteostasis, dysfunction of lipid homeostasis, and mitochondrial dysfunction form an internal feedback loop that causes the RPE to fail and allows accumulation of abnormal misfolded proteins and abnormal lipids that will form drusen. An inadequate antioxidant response, deficits in autophagy mechanisms, and dysregulation of the extracellular matrix (ECM) help to increase the deposition of abnormal drusen material over time. The drusen then act as inflammatory centers that trigger chronic inflammation of the subretinal space in which microglia and recruited macrophages are also involved, and where the complement system is a key component. Choriocapillaris degeneration and nutritional influences are also classic elements recognized in the AMD pathophysiology. The genetic component of the disease is embodied in the recognition of the described risk or protective polymorphisms of some complement and ECM related genes (mainly CFH and ARMS2/HTRA1). Thus, carriers of the risk haplotype at ARMS2/HTRA1 have a higher risk of developing late AMD at a younger age. Finally, gut microbiota and epigenetics may play a role in modulating the progression to advanced AMD with the presence of local inflammatory conditions. Because of multiple implicated processes, different complex combinations of treatments will probably be the best option to obtain the best visual results; they in turn will differ depending on the type and spectrum of disease affecting individual patients or the disease stage in each patient at a specific moment. This will undoubtedly lead to personalized medicine for control and hopefully find a future cure. This necessitates the continued unraveling of all the processes involved in the pathogenesis of AMD that must be understood to devise the combinations of treatments for different concurrent or subsequent problems.

Choroidal Vascular Impairment in Intermediate Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a multifactorial disease, whose complete pathogenesis is still unclear. Local hemodynamics may play a crucial role in its manifestation and progression. To evaluate choroidal and retinal vascular parameters, a total of 134 eyes were analyzed, 100 with intermediate AMD and 34 age matched healthy controls. 131 eyes of 104 patients were eligible for complete image assessment and 3 eyes were excluded for insufficient image quality: Group 1: intermediate AMD (n = 97) and Group 2: healthy controls (n = 34). Spectral domain optic coherence tomography (SD-OCT) with enhanced depth imaging (EDI) and optic coherence tomography angiography (OCT-A) were acquired using Spectralis (Heidelberg Engineering). Choroid and retinal capillary plexus were evaluated and image binarization was used to obtain quantitative data. Mean age was 77.67 years old (YO) and 67.2% were women. Total subfoveal choroidal area and luminal area were significantly reduced in Group 1 compared with Group 2 (0.88 mm2 and 0.40 mm2 vs. 1.24 mm2 and 0.55 mm2, respectively) (p < 0.05). Regarding choriocapillary flow density, AMD eyes recorded reduced values (34.83%) compared with controls (36.25%) (p < 0.05). Chorioretinal vasculature is impaired in intermediate AMD patients and vascular parameters could be attractive new prognostic biomarkers. Future therapeutic approaches may target this vascular dysfunction and delay disease progression.

Unilateral Cilioretinal Artery and Advanced Age-Related Macular Degeneration: A Retrospective Cross-Sectional Study

PURPOSE

To investigate the association between the presence of a cilioretinal artery (CRA) and advanced age-related macular degeneration (AMD), including the prevalence of choroidal neovascularization (CNV) and geographic atrophy (GA).

DESIGN

Retrospective cross-sectional study.

METHODS

This was a single-center study. A total of 738 patients with AMD who underwent optical coherence tomography angiography (OCTA) were included in the study. Fundus photographs were reviewed to determine the presence of the CRA. In patients with a unilateral CRA, paired tests were performed between eyes with and without the CRA to compare AMD severity and prevalence of CNV and GA. The main outcomes of interest were AMD stage and prevalence of CNV and GA. Macular vasculature, including vessel density, perfusion density, and foveal avascular zone, were examined using OCTA.

RESULTS

A total of 174 eyes from 87 patients with a unilateral CRA were examined. A total of 27.8% and 8.1% of patients had a CRA in 1 eye and both eyes, respectively. Eyes with a CRA showed lower AMD stage (4-step AREDS category; P = .037) and a lower prevalence of CNV (23.0% vs 41.4%; P = .024) than those without a CRA. The prevalence of GA and macular vessel density, perfusion density, and foveal avascular zone measured by OCTA were similar in both groups.

CONCLUSIONS

In the eyes with a CRA, AMD stage and prevalence of CNV were lower than those in the eyes without a CRA. However, the effect of the CRA on the macular vascular system remains unclear.

Etiopathogenesis of non-exudative age-related macular degeneration (literature review)

The article presents an overview of modern publications on epidemiology, risk factors, and the main links of the etiology and pathogenesis of age-related macular degeneration (AMD). The nonexudative or “dry” form of age-related macular degeneration is a multifactorial progressive pathological process caused by hereditary predisposition, general and local disorders of lipid metabolism, negative changes in  the blood supply to the eye, age-related destruction of the Bruch’s membrane and retinal pigment epithelium, the appearance of signs of local and systemic inflammation, the development of oxidative stress with the impact of toxic lipoperoxidation products on the structures of the posterior segment of the eye. Recent studies have discovered new ways of retinal pigment epithelial cell death in response to oxidative stress in AMD, in particular necroptosis, which, in addition to classical apoptosis, is considered the main mechanism of this process. It is noted that the development of AMD may be associated with an age-related decrease in the level of estrogen in women. The analysis of the data on the etiopathogenesis of age-related macular degeneration presented in the modern literature indicates the need for further research and generalization of local and general pathological processes developing in the dynamics of retinal visual function disorders by specialists of various scientific disciplines. 

A histological study of atherosclerotic characteristics in age-related macular degeneration

This study investigated the pathogenesis of age-related macular degeneration (AMD) using histological methods that are commonly used for atherosclerotic vascular disease (ASVD). 1 normal, 3 early dry AMD, and 1 late dry AMD eyes were obtained from the Lions Eye Bank of Oregon and systematically dissected. They were stained with hematoxylin and eosin, Oil red O, Masson, Elastica van Gieson, Alizarin red, and Prussian blue. Additionally, the normal and late dry AMD eyes were immunostained for a-smooth muscle actin, CD45, and CD68 with Nile red and DAPI. Correlations were found between severity of AMD and lipid accumulation in the deep sclera (+), numbers of drusen between the Bruch's membrane and retinal pigment epithelium (RPE) (+), amount of collagen in the deep sclera (+), and amount of elastin in the deep sclera (-) (P < 0.1). Geographic atrophy, RPE detachment, and abnormal capillary shape and distribution in the choriocapillaris were observed in the fovea of late AMD. There were no stenosis, plaque, hemorrhage, and calcification. Additionally, late AMD tended to have higher smooth muscle thicknesses of the choroidal vascular walls, lower numbers of T lymphocytes in the choroid, and higher numbers of macrophages near the RPE and in the choroid relative to normal (P < 0.1). Macrophages-derived foam cells were detected near the Bruch's membrane in late AMD. Therefore, the present study showed many histological characteristics of ASVD in AMD, which suggests an association between them; however, there were also some histological characteristics of ASVD that were not found in AMD, which indicates that there exist pathogenic differences between them. The results generally support the vascular model of AMD, but some details still need clarification.

Age-related macular degeneration: Epidemiology, genetics, pathophysiology, diagnosis, and targeted therapy

Age-related macular degeneration (AMD) is a complex eye disorder and is the leading cause of incurable blindness worldwide in the elderly. Clinically, AMD initially affects the central area of retina known as the macula and it is classified as early stage to late stage (advanced AMD). The advanced AMD is classified into the nonexudative or atrophic form (dry AMD) and the exudative or neovascular form (wet AMD). More severe vision loss is typically associated with the wet form. Multiple genetic factors, lipid metabolism, oxidative stress and aging, play a role in the etiology of AMD. Dysregulation in genetic to AMD is established to 46%-71% of disease contribution, with CFH and ARMS2/HTRA1 to be the two most notable risk loci among the 103 identified AMD associated loci so far. Chronic cigarette smoking is the most proven consistently risk living habits for AMD. Deep learning algorithm has been developed based on image recognition to distinguish wet AMD and normal macula with high accuracy. Currently, anti-vascular endothelial growth factor (VEGF) therapy is highly effective at treating wet AMD. Several new generation AMD drugs and iPSC-derived RPE cell therapy are in the clinical trial stage and are promising to improve AMD treatment in the near future.

An Objective Perimetry Study of Central Versus Peripheral Sensitivities and Delays in Age-Related Macular Degeneration

Purpose

The purpose of this study was to compare central versus peripheral retinal sensitivities and delays in neovascular age-related macular degeneration (nAMD) using US Food and Drug Administration (FDA)-cleared multifocal pupillographic objective perimetry (mfPOP).

Methods

We recruited 18 patients with nAMD and commenced Pro re nata intravitreal anti- vascular endothelial growth factor (VEGF) injection. We compared macular (±15 degrees) and wide-field (±30 degrees) mfPOP variants. We examined temporal correlations between treated and untreated fellow eyes. We fitted linear models to selected treatment patterns, and compared the ability of central versus peripheral responses to predict the need for treatment.

Results

Central sensitivity decreased by -2.23 ± 0.051 dB/month (P < 0.0002) in treated eyes, and -0.17 ± 0.07 dB/month (P = 0.033) in untreated eyes. Treated eyes showed quicker central responses by 13.08 ± 3.77 ms than untreated eyes (P = 0.001). Based on peripheral responses, we identified two eye-types. Among positive-eyes peripheral sensitivity increased by 9.88 ± 4.41 dB (P = 0.042) before treatment; delays increased by 3.49 ± 1.75 ms/month (P = 0.049). For negative-eyes peripheral delays were shorter a month before treatment by 9.38 ± 3.59 ms (P = 0.013). Correlations between treatment and peripheral sensitivities or delays peaked at 1 to 2 months post-treatment. Peripheral data significantly determined treatment frequency and final acuity (all P < 0.044).

Conclusions

Peripheral macular function of treated and untreated eyes divided eyes into positive and negative groups. Those peripheral responses determined outcomes; changes preceding active disease by 1 to 3 months. Overall, mfPOP may provide potential biomarkers to assist nAMD management.

Translational Relevance

Objective perimetry may identify the requirement for treatment in nAMD that accords with the decision of a skilled clinician based on optical coherence tomography (OCT) and clinical findings.

Choroidal Changes in Eyes With Polypoidal Choroidal Vasculopathy After Anti-VEGF Therapy Imaged With Swept-Source OCT Angiography

Purpose

Swept-source optical coherence tomography angiography was used to investigate choroidal changes and their association with pigment epithelial detachments (PEDs) in eyes with polypoidal choroidal vasculopathy (PCV) after treatment with vascular endothelial growth factor (VEGF) inhibitors.

Methods

Patients with treatment-naïve PCV were included and underwent anti-VEGF therapy. Mean choroidal thickness (MCT), choroidal vascularity index (CVI), and PED volume measurements were obtained before and after treatment.

Results

Thirty-four treatment-naïve PCV eyes from 33 patients were included. The PED volume decreased after treatment (P < 0.05). The MCT decreased from 223.0 ± 79.6 µm at baseline to 210.9 ± 76.2 µm after treatment (P < 0.001). The CVI at baseline was 0.599 ± 0.024, and the CVI after treatment was 0.602 ± 0.023 (P = 0.16). There was a correlation between the decreased PED volumes and the decreased MCT measurements (r = 0.47; P = 0.006). Also, there was a correlation between the decreased PED volumes and the increased CVI measurements (r = −0.63; P < 0.001).

Conclusions

In treatment-naïve eyes with PCV, the decreases in PED volumes were correlated with the decrease in MCT and the increase in CVI measurements. We propose that, at baseline, the PCV lesions serve as high-volume arteriovenous shunts between choroidal arterial and venous circulation, causing transudation into the choroidal stroma. We propose that, after treatment, the blood flow through the vascular shunt is reduced, the excess stromal transudation is resorbed, and the exudation from the neovascular lesion is reduced, resulting in thinning of the choroid, resolution of the PEDs, and an increase in the CVI due to the resorption of excess choroidal transudation.

Analysis focusing on plasma von Willebrand factor in pachychoroid neovasculopathy and age-related macular degeneration

Pachychoroid neovasculopathy (PNV) is a new concept of macular disorder. Some cases diagnosed as age-related macular degeneration (AMD) have been re-diagnosed as PNV. However, the biological features of PNV are still uncertain. The purpose of this study was to compare PNV and AMD by analyses focusing on von Willebrand factor (VWF) and complement factor H (CFH). Ninety-seven patients who were previously diagnosed with treatment naïve AMD were enrolled in this study. They were re-classified as either PNV or AMD based on the clinical criteria and 33 patients were classified as PNV and 64 patients as AMD. We examined the clinical data, analyzed VWF multimer and two genetic polymorphisms (I62V and Y402H) in the CFH. PNV group was significantly younger than AMD group (P = 0.001). In both I62V and Y402H, there were no significant differences between PNV and AMD while the recessive homozygous (AA) was found only in PNV group in I62V. The presence of unusually large VWF multimers (UL-VWFMs) and subretinal hemorrhages were significantly higher in PNV than in AMD (P = 0.045, P = 0.020, respectively). Thus, the residual UL-VWFMs may result in platelet thrombosis and hemorrhages in the choriocapillaris of PNV. In conclusion, our results suggest the biological differences between PNV and AMD.

The impact of vascular risk factors on the thickness and volume of the choroid in AMD patients

Disturbances in choroidal microcirculation may lead to the onset and progression of age-related macular degeneration (AMD). We aimed to assess changes in the choroidal volume and thickness in the macular region in AMD eyes and to investigate whether coexisting vascular risk factors alter choroidal status. We enrolled 354 AMD patients (175 dry, 179 wet AMD) and 121 healthy controls. All participants underwent a complete ophthalmologic examination and assessment of choroidal thickness and volume. A multivariate analysis adjusted for age, sex, and smoking status revealed that wet AMD was an independent factor associated with higher average thickness of the central ring area (ATC) and average volume of the central ring area (AVC) and lower choroidal vascularity index (CVI) compared to controls (β =  + 0.18, p = 0.0007, β =  + 0.18, p = 0.0008, respectively) and to dry AMD (β =  + 0.17, p = 0.00003 for both ATC and AVC and β =  - 0.30 p < 0.0001 for CVI). ATC, AVC and average volume (AV) were lower in AMD patients with hypertension and ischaemic heart disease (IHD). The duration of hypertension was inversely correlated with ATC, AVC and AV (Rs =  - 0.13, p < 0.05; Rs =  - 0.12; p < 0.05, Rs =  - 0.12; p < 0.05, respectively) while IHD duration negatively correlated with AV (Rs =  - 0.15, p < 0.05). No such associations were observed in the control group. Our findings show that the choroidal vascular system in eyes with AMD is much more susceptible to damage in the presence than in the absence of systemic vascular disease.

Retinal Vessel Functionality Is Linked With ARMS2 A69S and CFH Y402H Polymorphisms and Choroidal Status in AMD Patients

Purpose

We aimed to investigate the reactivity of retinal vessels to a flickering stimulus in patients with age-related macular degeneration (AMD) and healthy participants. We also assessed whether the parameters of retinal vessels are dependent on genetic predisposition.

Methods

A total of 354 patients with AMD and 121 controls were recruited for the study. All participants underwent thorough ophthalmologic examination and static and dynamic retinal vessel analysis. AMD risk polymorphisms were genotyped in the CFH and ARMS2 genes.

Results

We found no differences between the AMD group and controls in central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), arteriovenous ratio (AVR), dynamic analysis of arteries (DAAs), or dynamic analysis of veins (DAVs). Eyes with early AMD presented with significantly higher AVR values than eyes with late AMD. In the AMD group, DAA correlated positively with both choroidal thickness (Rs = 0.14, P = 0.00096) and choroidal volume (Rs = 0.23, P < 0.0001), and no such associations were observed in the controls. We found significantly lower DAA (1.47 ± 1.50) in TT homozygotes for the ARMS2 A69S polymorphism in comparison with GG homozygotes (2.38 ± 1.79) and patients with GG + GT genotypes (2.28 ± 1.84). We also observed less prominent DAV (3.24 ± 1.71) in patients with TC + CC genotypes in the CFH Y402H polymorphism compared with TT homozygotes (3.83 ± 1.68).

Conclusions

Our findings suggest that retinal microcirculation appears to be associated with the genetic background, choroidal parameters, and clinical features of the patients with AMD.

Retinal biomarkers for Alzheimer's disease and vascular cognitive impairment and dementia (VCID): implication for early diagnosis and prognosis

Cognitive impairment and dementia are major medical, social, and economic public health issues worldwide with significant implications for life quality in older adults. The leading causes are Alzheimer's disease (AD) and vascular cognitive impairment/dementia (VCID). In both conditions, pathological alterations of the cerebral microcirculation play a critical pathogenic role. Currently, the main pathological biomarkers of AD-β-amyloid peptide and hyperphosphorylated tau proteins-are detected either through cerebrospinal fluid (CSF) or PET examination. Nevertheless, given that they are invasive and expensive procedures, their availability is limited. Being part of the central nervous system, the retina offers a unique and easy method to study both neurodegenerative disorders and cerebral small vessel diseases in vivo. Over the past few decades, a number of novel approaches in retinal imaging have been developed that may allow physicians and researchers to gain insights into the genesis and progression of cerebromicrovascular pathologies. Optical coherence tomography (OCT), OCT angiography, fundus photography, and dynamic vessel analyzer (DVA) are new imaging methods providing quantitative assessment of retinal structural and vascular indicators-such as thickness of the inner retinal layers, retinal vessel density, foveal avascular zone area, tortuosity and fractal dimension of retinal vessels, and microvascular dysfunction-for cognitive impairment and dementia. Should further studies need to be conducted, these retinal alterations may prove to be useful biomarkers for screening and monitoring dementia progression in clinical routine. In this review, we seek to highlight recent findings and current knowledge regarding the application of retinal biomarkers in dementia assessment.

Retinal and choroidal capillaries contribution to age-related macular degeneration (AMD) phenotypes in murine models of the disease

Mouse models of age-related macular degeneration (AMD) such as Ccl2^-/- and Ccl2^-/-/Cx3cr1^-/- have not yet been fully characterized ultrastructurally. Although we have previously shown extranuclear DNA (enDNA) leakage into the cytoplasm and damaged mitochondria in the retinal pigment epithelium (RPE) of these AMD mouse models, little is known about the state of their vascular capillaries of the retina and choroid. Our ultrastructural survey shows that the aberrations were not restricted to the RPE cells, but also extended to the vasculature of the retina and choroid. Their endothelial aberrations included cytoplasmic degeneration, pyknotic DNA, hypertrophic nuclei, and loss of fenestration in addition to duplication of basement membrane and loss of density in Bruch's membrane. Moreover, the state of the vasculature in the mutant mice models suggests that the capillaries could also be active contributors to the pathological findings seen in AMD. The goal of this study is to gain insights into the early events of AMD that may lead to a better understanding of AMD's pathogenesis, improve our preventative measures, and formulate designed therapeutic regimens that are tailored to target the initial pathological events.Abbreviations: AMD: age-related macular degeneration; BM: Bruch's membrane; DPC: degenerate pericyte; EN: endothelial nucleus; enDNA: extranuclear DNA; GCL: ganglion cell layer; HEN: hypertrophic endothelial nucleus; IPL: inner plexiform layer; NFL: nerve fiber layer; OPL: outer plexiform layer; RBC: red blood cell; RPE: retinal pigment epithelium; SNPs: Single nucleotide polymorphisms.

CHOROIDAL THICKNESS, VASCULAR FACTORS, AND AGE-RELATED MACULAR DEGENERATION: The ALIENOR Study

PURPOSE

To study the associations of subfoveal choroidal thickness with vascular risk factors and age-related macular degeneration.

METHODS

Two hundred sixty-one participants of the Alienor study had gradable enhanced-depth imaging optical coherence tomography scans of the macula and available data on vascular and genetic risk factors (assessed through face-to-face interview and fasting blood samples) and age-related macular degeneration status (assessed from retinal photographs and optical coherence tomography). Subfoveal choroidal thickness was measured manually on one horizontal scan passing through the fovea.

RESULTS

In a multivariate mixed linear model, subfoveal choroidal thickness was independently associated with age greater than 80 years (-21.77 μm, P = 0.02), axial length (-21.77 μm, P < 0.0001), heavy smoking (≥20 pack-years: -24.89 μm, P = 0.05), fasting blood glucose higher than 7 mmol/L (-53.17 μm, P = 0.02), and lipid-lowering treatment (+18.23, P = 0.047). After multivariate adjustment for age, sex, axial length, and vascular and genetic risk factors, subfoveal choroidal thickness was thinner in eyes with central hyperpigmentation (-45.39 μm, P = 0.006), central hypopigmentation (-44.99 μm, P = 0.001), and central pigmentary abnormalities (-44.50 μm, P = 0.001), but not in eyes with late age-related macular degeneration (-18.05 μm, P = 0.33) or soft drusen.

CONCLUSION

These findings indicate a relationship between vascular risk factors and choroidal thinning and suggest an early involvement of the choroid in the pathogenesis of age-related macular degeneration.

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.

Oral Delivery of a Tetrameric Tripeptide Inhibitor of VEGFR1 Suppresses Pathological Choroid Neovascularization

Age-related macular degeneration (AMD) is the primary cause of blindness in advanced countries. Repeated intravitreal delivery of anti-vascular endothelial growth factor (VEGF) agents has represented an important advancement for the therapy of wet AMD with significative results in terms of blindness prevention and partial vision restore. Nonetheless, some patients are not responsive or do not attain significant visual improvement, intravitreal injection may cause serious complications and important side effects have been reported for the prolonged block of VEGF-A. In order to evaluate new anti-angiogenic strategies, we focused our attention on VEGF receptor 1 (VEGFR1) developing a specific VEGFR-1 antagonist, a tetrameric tripeptide named inhibitor of VEGFR 1 (iVR1). We have evaluated its anti-angiogenic activity in the preclinical model of AMD, the laser-induced choroid neovascularization (CNV). iVR1 is able to potently inhibit CNV when delivered by intravitreal injection. Surprisingly, it is able to significantly reduce CNV also when delivered by gavage. Our data show that the specific block of VEGFR1 in vivo represents a valid alternative to the block of VEGF-A and that the inhibition of the pathological neovascularization at ocular level is also possible by systemic delivery of compounds not targeting VEGF-A.

Microvascular contributions to age-related macular degeneration (AMD): from mechanisms of choriocapillaris aging to novel interventions

Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the eye, changes in the choroid and choroidal microcirculation (choriocapillaris) also occur with age, and these changes can play a critical role in the pathogenesis of age-related macular degeneration (AMD). In order to develop novel treatments for amelioration of choriocapillaris aging and prevention of AMD, it is essential to understand the cellular and functional changes that occur in the choroid and choriocapillaris during aging. In this review, recent advances in in vivo analysis of choroidal structure and function in AMD patients and patients at risk for AMD are discussed. The pathophysiological roles of fundamental cellular and molecular mechanisms of aging including oxidative stress, mitochondrial dysfunction, and impaired resistance to molecular stressors in the choriocapillaris are also considered in terms of their contribution to the pathogenesis of AMD. The pathogenic roles of cardiovascular risk factors that exacerbate microvascular aging processes, such as smoking, hypertension, and obesity as they relate to AMD and choroid and choriocapillaris changes in patients with these cardiovascular risk factors, are also discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay AMD by targeting fundamental cellular and molecular aging processes are presented.

Association Between Cilioretinal Arteries and Advanced Age-Related Macular Degeneration: Secondary Analysis of the Comparison of Age-Related Macular Degeneration Treatment Trials (CATT)

Importance

Recent reports suggest that cilioretinal arteries (CRAs) confer protection against developing advanced age-related macular degeneration (AMD).

Objective

To further characterize the association between the presence of a CRA and incidence of geographic atrophy (GA) or choroidal neovascularization (CNV).

Design

This cohort study constituted an ad hoc secondary analysis of data from the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT) and was performed at 44 clinical centers in the United States among participants in CATT with CNV in the study eye and without advanced AMD in the fellow eye at baseline. The presence of a CRA was determined by 2 graders, masked to clinical data, using color fundus photographs, red-free fundus photographs, and fluorescein angiography. The proportion with CRAs at baseline between the study eye with CNV and fellow eye without CNV was first compared. The association of a CRA with incidence of CNV or GA at 5 years among fellow eyes and with incidence of GA among study (treated) eyes was then assessed. In addition, the association of CRAs with the Age-Related Eye Disease Study severity scale among the fellow eyes at baseline was assessed. Data were collected from February 1, 2008, through April 30, 2015, and analyzed from July 1, 2018, through April 30, 2019.

Exposures

Presence of a CRA.

Main Outcomes and Measures

The association between the presence of a CRA and incidence of CNV or GA at 5 years of follow-up.

Results

A total of 350 patients (700 eyes) (230 [65.7% women; mean [SD] age, 77 [7.2] years) were included in the analysis. Cilioretinal arteries were present in 67 of 345 (19.4%) fellow eyes without baseline CNV and 73 of 349 (20.9%) study eyes with baseline CNV (P = .60). Cilioretinal arteries in fellow eyes were not associated with incidence of CNV at 5 years (125 of 278 [45.0%] among eyes without CRAs and 30 of 67 [44.8%] among eyes with CRAs; P = .99) or with incidence of GA at 5 years (110 of 278 [39.6%] among eyes without CRAs and 25 of 67 [37.3%] among eyes with CRAs; P = .89). Cilioretinal arteries in study eyes were not associated with incidence of GA at 5 years (105 of 276 [38.0%] study eyes without CRAs and 26 of 73 [35.6%] study eyes with CRAs; P = .72).

Conclusions and Relevance

The analysis did not find a protective association between CRAs and incidence of CNV or GA among CATT participants who had unilateral exudative AMD. Why these findings were different from those of previous publications is unclear but may be partially explained by the different techniques used to detect CRAs or by the baseline advanced disease in CATT participants.

Trial Registration

ClinicalTrials.gov identifier: NCT00593450.

Vascular Inflammation Risk Factors in Retinal Disease

Inflammation of the blood vessels that serve the central nervous system has been increasingly identified as an early and possibly initiating event among neurodegenerative conditions such as Alzheimer's disease and related dementias. However, the causal relevance of vascular inflammation to major retinal degenerative diseases is unresolved. Here, we describe how genetics, aging-associated changes, and environmental factors contribute to vascular inflammation in age-related macular degeneration, diabetic retinopathy, and glaucoma. We highlight the importance of mouse models in studying the underlying mechanisms and possible treatments for these diseases. We conclude that data support vascular inflammation playing a central if not primary role in retinal degenerative diseases, and this association should be a focus of future research.

The Association of Aspirin Use with Age-Related Macular Degeneration Progression in the Age-Related Eye Disease Studies: Age-Related Eye Disease Study 2 Report No. 20

PURPOSE

To analyze the potential association between aspirin use and progression of age-related macular degeneration (AMD).

DESIGN

Two prospective cohort studies within 2 controlled clinical trials of oral supplementation for age-related eye disease.

PARTICIPANTS

Age-Related Eye Disease Study (AREDS) participants 55 to 80 years of age and AREDS2 participants 50 to 85 years of age.

METHODS

Propensity scores for aspirin use were calculated for AREDS and AREDS2 participants separately by logistic regression. Of the participants without late AMD (geographic atrophy [GA] or neovascular AMD) in either eye at study baseline, aspirin users were matched 1:1 with nonusers by propensity score (separately for AREDS and AREDS2). Proportional hazards regression was performed, adjusting for age, on the matched participants to evaluate associations between aspirin propensity score and progression to late AMD (and its subtypes).

MAIN OUTCOME MEASURES

Progression to late AMD on color fundus photographs, graded centrally.

RESULTS

Of the 3734 eligible AREDS participants, 1049 (28.1%) were taking aspirin, and of the 2403 eligible AREDS2 participants, 1198 (49.9%) were taking aspirin. After matching by propensity score, the characteristics of the users and nonusers were similar in both studies. Of the 1950 matched AREDS participants and 1694 matched AREDS2 participants, over a median follow-up of 10.1 years and 5.0 years, respectively, the numbers who progressed to late AMD, GA, or neovascular AMD were 454 (23.3%), 345 (17.7%), and 278 (14.3%), respectively, in AREDS and 643 (38.0%), 402 (24.6%), and 341 (20.1%) in AREDS2. The hazard ratios of progression in quintile 5 (highest propensity for aspirin use) versus 1 (reference) were 1.17 (P = 0.35), 1.24 (0.25), and 0.95 (0.81), respectively, in AREDS and 1.26 (0.09), 1.46 (0.03), and 1.12 (0.58) in AREDS2. No significant association with progression to late AMD was observed for quintiles 2 through 5 for any of the 3 outcomes in either study.

CONCLUSIONS

Aspirin use was not associated significantly with progression to late AMD or its subtypes in either the AREDS or AREDS2. Patients with AMD need not avoid aspirin for this reason when its use is medically indicated.

The role of complement membrane attack complex in dry and wet AMD - From hypothesis to clinical trials

Data from human dry and wet age-related macular degeneration (AMD) eyes support the hypothesis that constant 'tickover' of the alternative complement pathway results in chronic deposition of the complement membrane attack complex (MAC) on the choriocapillaris and the retinal pigment epithelium (RPE). Sub-lytic levels of MAC lead to cell signaling associated with tissue remodeling and the production of cytokines and inflammatory molecules. Lytic levels of MAC lead to cell death. CD59 is a naturally occurring inhibitor of the assembly of MAC. CD59 may thus be therapeutically efficacious against the pathophysiology of dry and wet AMD. The first gene therapy clinical trial for geographic atrophy - the advanced form of dry AMD has recently completed recruitment. This trial is studying the safety and tolerability of expressing CD59 from an adeno-associated virus (AAV) vector injected once into the vitreous. A second clinical trial assessing the efficacy of CD59 in wet AMD patients is also under way. Herein, the evidence for the role of MAC in the pathophysiology of dry as well as wet AMD and the scientific rationale underlying the use of AAV- delivered CD59 for the treatment of dry and wet AMD is discussed.

Novel function of VEGF-B as an antioxidant and therapeutic implications

Oxidative stress, due to insufficiency of antioxidants or over-production of oxidants, can lead to severe cell and tissue damage. Oxidative stress occurs constantly and has been shown to be involved in innumerable diseases, such as degenerative, cardiovascular, neurological, and metabolic disorders, cancer, and aging, thus highlighting the vital need of antioxidant defense mechanisms. Vascular endothelial growth factor B (VEGF-B) was discovered a long time ago, and is abundantly expressed in most types of cells and tissues. VEGF-B remained functionally mysterious for many years and later on has been shown to be minimally angiogenic. Recently, VEGF-B is reported to be a potent antioxidant by boosting the expression of key antioxidant enzymes. Thus, one major role of VEGF-B lies in safeguarding tissues and cells from oxidative stress-induced damage. VEGF-B may therefore have promising therapeutic utilities in treating oxidative stress-related diseases. In this review, we discuss the current knowledge on the newly discovered antioxidant function of VEGF-B and the related molecular mechanisms, particularly, in relationship to some oxidative stress-related diseases, such as retinitis pigmentosa, age-related macular degeneration, diabetic retinopathy, glaucoma, amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease.

Asian age-related macular degeneration: from basic science research perspective

In Asian populations, polypoidal choroidal vasculopathy (PCV), a distinct phenotype of neovascular age-related macular degeneration (AMD), is more prevalent than Caucasians. Recently, there has been significant focus on how PCV differs from typical AMD. Although typical AMD and PCV share a variety of mechanisms by which abnormal angiogenic process occurs at the retinochoroidal interface, PCV has different clinical characteristics such as aneurysm-like dilation at the terminal of choroidal neovascular membranes, less frequent drusen and inner choroidal degeneration due to the thickened choroid. Recent studies support an important role for inflammation, angiogenesis molecules and lipid metabolism in the pathogenesis of neovascular AMD. Furthermore, although less attention has been paid to the role of the choroid in AMD, accumulating evidence suggests that the choriocapillaris and choroid also play a pivotal role in drusenogenesis, typical AMD and PCV. This review discusses the basic pathogenic mechanisms of AMD and explores the difference between typical AMD and PCV.

Generation of an immortalized human choroid endothelial cell line (iChEC-1) using an endothelial cell specific promoter

Age-related macular degeneration (AMD) is a common cause of blindness worldwide. While recent studies have revealed that the loss of choroidal endothelial cells (ChECs) is critical to the disease pathogenesis of dry AMD, in vitro studies are needed to fully elucidate the disease mechanism. However, these studies remain hindered due to the lack of publically available human ChEC lines. To address this need, ChECs were harvested form donor tissue and enriched for by using magnetic cell separation using anti-CD31 conjugated microbeads. Next, lenti-viral vectors with endothelial-specific promoters driving genes necessary for immortalization, CDH5p-hTERT and CDH5p TAg, were generated. Stable integration of both gene cassettes allowed cells to maintain their proliferative state and yielded an immortalized cell line (iChEC-1). Immunocytochemical analysis of iChEC-1 confirmed the expression of important ChEC markers such as CA4, a marker of choriocapillaris endothelial cells, CDH5, and CD34, pan-endothelial cell markers. qRT-PCR analysis of expanded clones from iChEC-1 further showed that the line maintained expression of other important endothelial markers, vWF, PECAM1, and PLVAP, similar to primary cells. Functional responses were characterized by tube-forming assays and repopulation of decellularized choroid with the immortalized cell line. In conclusion, the iChEC-1 line presents a suitable immortalized human ChEC line for future in vitro studies of AMD.

RF/6A Chorioretinal Cells Do Not Display Key Endothelial Phenotypes

Purpose

The misuse of inauthentic cell lines is widely recognized as a major threat to the integrity of biomedical science. Whereas the majority of efforts to address this have focused on DNA profiling, we sought to anatomically, transcriptionally, and functionally authenticate the RF/6A chorioretinal cell line, which is widely used as an endothelial cell line to model retinal and choroidal angiogenesis.

Methods

Multiple vials of RF/6A cells obtained from different commercial distributors were studied to validate their genetic, transcriptomic, anatomic, and functional fidelity to bona fide endothelial cells.

Results

Transcriptomic profiles of RF/6A cells obtained either de novo or from a public data repository did not correspond to endothelial gene expression signatures. Expression of established endothelial markers were very low or undetectable in RF/6A compared to primary human endothelial cells. Importantly, RF/6A cells also did not display functional characteristics of endothelial cells such as uptake of acetylated LDL, expression of E-selectin in response to TNF-α exposure, alignment in the direction of shear stress, and AKT and ERK1/2 phosphorylation following VEGFA stimulation.

Conclusions

Multiple independent sources of RF/6A do not exhibit key endothelial cell phenotypes. Therefore, these cells appear unsuitable as surrogates for choroidal or retinal endothelial cells. Further, cell line authentication methods should extend beyond genomic profiling to include anatomic, transcriptional, and functional assessments.

Xanthohumol Protects Morphology and Function in a Mouse Model of Retinal Degeneration

Purpose

To investigate whether treatment with xanthohumol (XN), the principal prenylated chalconoid from Humulus lupulus (hops), is protective in a mouse model of light-induced retinal degeneration (LIRD).

Methods

Mice (129S2/SvPasCrl) were intraperitoneally injected with vehicle or XN prior to toxic light exposure and every 3 days thereafter. Retinal function was assessed by electroretinograms at 1, 2, and 4 weeks following toxic light exposure. Visual acuity was tested by optokinetic tracking 1 week and 4 weeks after toxic light exposure. Retina sections were stained with hematoxylin and eosin for morphologic analysis or by TUNEL. Redox potentials were assessed in retinal tissue by measuring levels of cysteine (CYS), cystine (CYSS), glutathione (GSH), and glutathione disulfide (GSSG) using HPLC with fluorescence detection.

Results

Toxic light significantly suppressed retinal function and visual acuity, severely disrupted the photoreceptor cell layer, and significantly decreased the number of nuclei and increased the accumulation of TUNEL-labeled cells in the outer nuclear layer. These effects were prevented by XN treatment. Treatment with XN also maintained GSSG and CYSS redox potentials and the total CYS pool in retinas of mice undergoing toxic light exposure.

Conclusions

XN treatment partially preserved visual acuity and retinal function in the LIRD mouse. Preservation of retinal CYS and of GSSG and CYSS redox potentials may indicate that XN treatment induces an increased antioxidant response, but further experiments are needed to verify this potential mechanism. To our knowledge, this is the first study to report protective effects of XN in a model of retinal degeneration.

Automatic measurement of global retinal circulation in fluorescein angiography

Examination of the retinal circulation in patients with retinal diseases is a clinical routine for ophthalmologists. In the present work, an automatic method is proposed for measuring the global retinal circulation in fluorescein angiography (FA). First, the perfusion region in FA images is segmented using a multiscale line detector. Then, the time evolution of the perfusion area is modeled using damped least-squares regression. Based on the perfusion area profile, some circulation parameters are defined to describe quantitatively the global retinal circulation. The effectiveness of the proposed method is tested using our own and public datasets, with reasonable results and satisfactory accuracy compared with manual measurement. The proposed method has good computing efficiency and thus has potential to be used in clinical practice for evaluation of global retinal circulation.

PDGF-C and PDGF-D in ocular diseases

PDGFs and their receptors are critical regulators of numerous tissues and organs, including the eye. Extensive studies have shown that PDGFs and their receptors play critical roles in many ocular neovascular diseases, such as neovascular age-related macular degeneration, retinopathy of prematurity, and proliferative vitreoretinopathy. In addition, PDGFs and PDGFRs are also important players in ocular diseases involving the degeneration of retinal neuronal and vascular cells, such as glaucoma and retinitis pigmentosa. Due to their critical roles in the pathogenesis of many blinding ocular diseases, the PDGFs and PDGFRs have been considered as important target molecules for the treatment of eye diseases. PDGF-C and PDGF-D are relatively new members of the PDGF family and are potent angiogenic and survival factors. Recent studies have demonstrated their important roles in different types of eye diseases. Thus, modulating PDGF-C and PDGF-D activities may have therapeutic values for the treatment of ocular neovascular and degenerative diseases. This review mainly summarizes the recent advances on PDGF-C and PDGF-D biology in relationship to some major ocular diseases.

Epidemiology of age-related macular degeneration (AMD): associations with cardiovascular disease phenotypes and lipid factors

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in adults over 50 years old. Genetic, epidemiological, and molecular studies are beginning to unravel the intricate mechanisms underlying this complex disease, which implicate the lipid-cholesterol pathway in the pathophysiology of disease development and progression. Many of the genetic and environmental risk factors associated with AMD are also associated with other complex degenerative diseases of advanced age, including cardiovascular disease (CVD). In this review, we present epidemiological findings associating AMD with a variety of lipid pathway genes, cardiovascular phenotypes, and relevant environmental exposures. Despite a number of studies showing significant associations between AMD and these lipid/cardiovascular factors, results have been mixed and as such the relationships among these factors and AMD remain controversial. It is imperative that researchers not only tease out the various contributions of such factors to AMD development but also the connections between AMD and CVD to develop optimal precision medical care for aging adults.