Analysis of Genetic and Environmental Risk Factors and Their Interactions in Korean Patients with Age-Related Macular Degeneration

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.

Canonical correlation analysis for multi-omics: Application to cross-cohort analysis

Integrative approaches that simultaneously model multi-omics data have gained increasing popularity because they provide holistic system biology views of multiple or all components in a biological system of interest. Canonical correlation analysis (CCA) is a correlation-based integrative method designed to extract latent features shared between multiple assays by finding the linear combinations of features-referred to as canonical variables (CVs)-within each assay that achieve maximal across-assay correlation. Although widely acknowledged as a powerful approach for multi-omics data, CCA has not been systematically applied to multi-omics data in large cohort studies, which has only recently become available. Here, we adapted sparse multiple CCA (SMCCA), a widely-used derivative of CCA, to proteomics and methylomics data from the Multi-Ethnic Study of Atherosclerosis (MESA) and Jackson Heart Study (JHS). To tackle challenges encountered when applying SMCCA to MESA and JHS, our adaptations include the incorporation of the Gram-Schmidt (GS) algorithm with SMCCA to improve orthogonality among CVs, and the development of Sparse Supervised Multiple CCA (SSMCCA) to allow supervised integration analysis for more than two assays. Effective application of SMCCA to the two real datasets reveals important findings. Applying our SMCCA-GS to MESA and JHS, we identified strong associations between blood cell counts and protein abundance, suggesting that adjustment of blood cell composition should be considered in protein-based association studies. Importantly, CVs obtained from two independent cohorts also demonstrate transferability across the cohorts. For example, proteomic CVs learned from JHS, when transferred to MESA, explain similar amounts of blood cell count phenotypic variance in MESA, explaining 39.0% ~ 50.0% variation in JHS and 38.9% ~ 49.1% in MESA. Similar transferability was observed for other omics-CV-trait pairs. This suggests that biologically meaningful and cohort-agnostic variation is captured by CVs. We anticipate that applying our SMCCA-GS and SSMCCA on various cohorts would help identify cohort-agnostic biologically meaningful relationships between multi-omics data and phenotypic traits.

Association between CX3CR1 rs3732378 polymorphism and neovascular age-related macular degeneration in a sample of Algerian population

Neovascular age-related macular degeneration (nAMD) is a progressive ocular disease, responsible for central visual loss and blindness in elderly population. Increase data demonstrate that genetic factors play an important role in pathogenesis process of this disease. The aim of this study is to investigate the association between rs3732378 polymorphism in CX3CR1 gene and nAMD in a sample of Algerian patients. This case-control study consisted of 72 patients with nAMD and 124 control subjects. DNA of participants was extracted using salting out method. Genotyping was carried out using the TaqMan real-time polymerase chain reaction method. Statistical analysis was performed by SPSS.21.0. The prevalence of the risk genotype AA was higher in the nAMD group than in control group (OR=5.02, 95% CI=1.44-17.4, P=0.011). In our sample of Algerian patients, the rs3732378 polymorphism is associated with nAMD. This result may support the role of CX3CR1 gene in the pathogenesis of nAMD.

Polypoidal Choroidal Vasculopathy Based on Non-ICGA Criteria in White Patients With Neovascular Age-Related Macular Degeneration

PURPOSE

To determine prevalence of probable polypoidal choroidal vasculopathy (PCV) among White patients with neovascular age-related macular degeneration (nAMD) using non-indocyanine green angiography (ICGA) criteria DESIGN: Multicenter, multinational, retrospective, cross-sectional study.

METHODS

A total of 208 treatment-naive eyes from Hispanic and non-Hispanic White individuals diagnosed with nAMD were included. All underwent color fundus photography (CFP), optical coherence tomography (OCT), and fluorescein angiography (FFA). De-identified images of study eyes were sent to 2 groups of graders. Group 1 reviewed CFP, OCT, and FFA to confirm nAMD diagnosis. Group 2 reviewed CFP and OCT to determine highly suggestive features for PCV. Probable PCV diagnosis defined as the presence of ≥2 of 4 highly suggestive features for PCV: notched or fibrovascular pigment epithelial detachment (PED) on CFP, sharply-peaked PED, notched PED, and hyperreflective ring on OCT.

RESULTS

Eleven eyes were excluded because of poor image quality (6) or non-nAMD diagnosis (5). Of 197 eligible eyes (197 patients), the mean age (SD) was 78.8 years (8.9), 44.2% were men, 26.4% were Hispanic, and 73.6% were non-Hispanic White individuals; 41.1%, 23.4%, 9.1%, and 2.5% had ≥1, ≥2, ≥3, and 4 highly suggestive features. Results showed that 23.4% (95% CI, 17.6%-29.9%) had probable PCV diagnosis. Predominantly occult CNV was more frequently found in probable PCV than nAMD subgroup (84.8% vs 64.9%, P = .01). Hispanic White individuals had a lower prevalence of probable PCV than non-Hispanic White individuals (9.6% vs 28.2%, P = .006) CONCLUSIONS: These findings suggest that probable PCV occurs between 17.6% and 29.9% in White individuals with nAMD, and more commonly in non-Hispanic than in Hispanic White individuals.

Proteomic genotyping of SNP of Complement Factor H (CFH) Y402H and I62V using multiple reaction monitoring (MRM) assays

The single nucleotide polymorphisms (SNPs) of complement factor H (CFH) gene are well-known genetic risk factors for age-related macular degeneration (AMD). To identify whether the measurement of plasma protein concentrations of CFH variants using the multiple reaction monitoring (MRM) assay can determine the genotypes of CFH SNP rs1061170 and rs800292, 120 patients with AMD and 26 controls were included in this study. The number of cases were TT:TC:CC = 121:24:1 in CFH SNP Y402H and GG:AG:AA = 72:57:17 in CFH SNP I62V. Plasma concentrations of tryptic peptides were measured using the MRM assay, and tyrosine/histidine (Y/H) and valine/isoleucine (V/I) CFH variant protein ratios were obtained. To discriminate the genotypes by the plasma protein ratios, cut-off values were set for Y/H ratios (TT: > 4.428; TC: 1.00-4.428; CC: < 1.00) and V/I ratios (GG: > 1.09; AG: 0.0089-1.08; AA: < 0.0089). Correlation analysis revealed that the plasma CFH variant protein ratios and genotypes of CFH were exactly matched (100%) without overlap in the total patients and controls. The measurement of plasma protein CFH variants using the MRM assay can accurately identify the genotypes of CFH SNPs of Y402H and I62V.

Current Trends in Clinical Characteristics, Diagnosis, and Treatment of Polypoidal Choroidal Vasculopathy: A Perspective from Vietnam

Polypoidal choroidal vasculopathy (PCV) is a common choroidal disease in the Asian population including Vietnam and is characterized by subretinal red-orange nodules, pigmented epithelium detachment, and massive subretinal hemorrhage. The recent focus on PCV in Vietnam can be attributed to advancements in PCV diagnosis and treatment. However, there is a scarcity of published literature and clinical data on PCV in the Vietnamese population, highlighting a key knowledge gap in this region. In order to address this gap, we gathered the opinions of experienced clinicians and retinal experts in Vietnam and reviewed available medical literature with the aim of: (i) providing an overview of PCV in the Vietnamese population—in terms of epidemiology, clinical characteristics, and management; (ii) tailoring international/national guidelines for the diagnosis and management of PCV, in line with available resources and medical equipment in Vietnam; and (iii) identifying gaps in clinical data in order to guide future PCV research in Vietnam and other countries with similar clinical conditions. The present review will enable healthcare providers and researchers to gain insight into current clinical practices and the limitations of PCV management in Vietnam and provide optimal and effective solutions.

Molecular Genetic Mechanisms in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is among the leading causes of irreversible blindness worldwide. In addition to environmental risk factors, such as tobacco use and diet, genetic background has long been established as a major risk factor for the development of AMD. However, our ability to predict disease risk and personalize treatment remains limited by our nascent understanding of the molecular mechanisms underlying AMD pathogenesis. Research into the molecular genetics of AMD over the past two decades has uncovered 52 independent gene variants and 34 independent loci that are implicated in the development of AMD, accounting for over half of the genetic risk. This research has helped delineate at least five major pathways that may be disrupted in the pathogenesis of AMD: the complement system, extracellular matrix remodeling, lipid metabolism, angiogenesis, and oxidative stress response. This review surveys our current understanding of each of these disease mechanisms, in turn, along with their associated pathogenic gene variants. Continued research into the molecular genetics of AMD holds great promise for the development of precision-targeted, personalized therapies that bring us closer to a cure for this debilitating disease.

Chemokine Receptor Profiles of T Cells in Patients with Age-Related Macular Degeneration

PURPOSE

To evaluate the expression of multiple chemokine receptors in peripheral blood T cells from patients with age-related macular degeneration (AMD).

MATERIALS AND METHODS

Peripheral blood mononuclear cells and/or aqueous humor were obtained from 24 AMD patients and 24 age- and sex-matched healthy controls. Chemokine receptor expression on T cells from peripheral blood was determined by multicolor flow cytometry. The levels of chemokines and cytokines in the aqueous humor from 12 AMD patients and six healthy controls were assessed.

RESULTS

AMD patients had increased expressions of CCR4 in CD4⁺ T cells (p=0.007) and CRTh2 in CD8⁺ T cells (p=0.002), and decreased expressions of CXCR3 in CD4⁺ T cells (p=0.029) and CXCR3, CCR5, and CX₃CR1 in CD8⁺ T cells (p=0.005, 0.019, and 0.007, respectively). Monocyte chemoattractant protein-1 levels were increased in the aqueous humor from AMD patients (p=0.018), while the levels of interleukin (IL)-4 and IL-22 were significantly decreased compared to controls (p=0.018 and 0.041, respectively).

CONCLUSION

The chemokine receptor profiles of T cells are altered in AMD patients compared to healthy controls without noticeable associations with chemokine levels in the aqueous humor. Further evaluation is needed to clarify the role of these alterations in AMD pathogenesis.

The Role of Inflammation in Retinal Neurodegeneration and Degenerative Diseases

Retinal neurodegeneration is predominantly reported as the apoptosis or impaired function of the photoreceptors. Retinal degeneration is a major causative factor of irreversible vision loss leading to blindness. In recent years, retinal degenerative diseases have been investigated and many genes and genetic defects have been elucidated by many of the causative factors. An enormous amount of research has been performed to determine the pathogenesis of retinal degenerative conditions and to formulate the treatment modalities that are the critical requirements in this current scenario. Encouraging results have been obtained using gene therapy. We provide a narrative review of the various studies performed to date on the role of inflammation in human retinal degenerative diseases such as age-related macular degeneration, inherited retinal dystrophies, retinitis pigmentosa, Stargardt macular dystrophy, and Leber congenital amaurosis. In addition, we have highlighted the pivotal role of various inflammatory mechanisms in the progress of retinal degeneration. This review also offers an assessment of various therapeutic approaches, including gene-therapies and stem-cell-based therapies, for degenerative retinal diseases.

Nerve Growth Factor-Based Therapy in Alzheimer's Disease and Age-Related Macular Degeneration

Alzheimer’s disease (AD) is an age-associated neurodegenerative disease which is the most common cause of dementia among the elderly. Imbalance in nerve growth factor (NGF) signaling, metabolism, and/or defect in NGF transport to the basal forebrain cholinergic neurons occurs in patients affected with AD. According to the cholinergic hypothesis, an early and progressive synaptic and neuronal loss in a vulnerable population of basal forebrain involved in memory and learning processes leads to degeneration of cortical and hippocampal projections followed by cognitive impairment with accumulation of misfolded/aggregated Aβ and tau protein. The neuroprotective and regenerative effects of NGF on cholinergic neurons have been largely demonstrated, both in animal models of AD and in living patients. However, the development of this neurotrophin as a disease-modifying therapy in humans is challenged by both delivery limitations (inability to cross the blood–brain barrier (BBB), poor pharmacokinetic profile) and unwanted side effects (pain and weight loss). Age-related macular degeneration (AMD) is a retinal disease which represents the major cause of blindness in developed countries and shares several clinical and pathological features with AD, including alterations in NGF transduction pathways. Interestingly, nerve fiber layer thinning, degeneration of retinal ganglion cells and changes of vascular parameters, aggregation of Aβ and tau protein, and apoptosis also occur in the retina of both AD and AMD. A protective effect of ocular administration of NGF on both photoreceptor and retinal ganglion cell degeneration has been recently described. Besides, the current knowledge about the detection of essential trace metals associated with AD and AMD and their changes depending on the severity of diseases, either systemic or locally detected, further pave the way for a promising diagnostic approach. This review is aimed at describing the employment of NGF as a common therapeutic approach to AMD and AD and the diagnostic power of detection of essential trace metals associated with both diseases. The multiple approaches employed to allow a sustained release/targeting of NGF to the brain and its neurosensorial ocular extensions will be also discussed, highlighting innovative technologies and future translational prospects.

Real-World Effectiveness, Treatment Pattern, and Safety of Ranibizumab in Korean Patients with Neovascular Age-Related Macular Degeneration: Subgroup Analyses from the LUMINOUS Study

Purpose

To evaluate the real-world effectiveness, treatment patterns, and safety of ranibizumab in Korean patients with neovascular age-related macular degeneration (nAMD).

Methods

LUMINOUS™ is a 5-year, global, prospective, observational, open-label study. Adults aged ≥18 years who were either treatment-naïve or prior-treated were enrolled and treated with ranibizumab 0.5 mg as per the local label. Outcome measures included mean (± standard deviation [SD]) changes from baseline in visual acuity (VA) and central retinal thickness (CRT), and rate of ocular and non-ocular adverse events (AEs).

Results

Overall, 367 Korean patients with nAMD (152 treatment-naïve and 215 prior-treated) were enrolled. The mean (SD) VA changes from baseline at 1-year were +10.1 (±21.77; P=0.0005) and +1.4 (±15.17; P=0.2142) Early Treatment Diabetic Retinopathy Study letters, with mean numbers of injections of 5.2 and 3.4 in the treatment-naïve and prior-treated groups, respectively. VA gains were greater in patients with lower baseline VA, who received a loading dose, and with polypoidal choroidal vasculopathy (PCV). Multivariate logistic regression analyses demonstrated younger age, worse baseline VA, and those who received loading dose being associated with higher odds of any gain in VA at 1 year (P<0.05). Mean (SD) CRT changes from baseline were –126.7 (±174.90) µm (P<0.0001) and +10.8 (±89.62) µm (P=0.5833) in the treatment-naïve and prior-treated groups, respectively, with greater reductions observed in patients with PCV. Ocular and non-ocular AEs were reported in 8.4% (n=31) and 10.1% (n=37) of patients, respectively.

Conclusion

The LUMINOUS study confirms real-world effectiveness and safety of ranibizumab in Korean patients with nAMD; factors including age, baseline VA, and loading-dose were associated with VA gain at one-year post-treatment.

Macular neovascularization in eyes with pachydrusen

The natural history and clinical significance of pachydrusen is unclear. This study aims to compare the longitudinal changes of eyes with pachydrusen and soft drusen and progression to exudative macular neovascularisation (MNV). Patients with a diagnosis of MNV in one eye only and the fellow eye was selected as the study eye. Study eyes were required to have pachydrusen or soft drusen on fundus photographs and follow up of at least 2 years or until exudative MNV occurred. Systematic grading was performed at baseline and change in drusen area and onset of exudative MNV recorded over the period of follow up. A total of 75 eyes from 75 patients (29 with pachydrusen and 46 with soft drusen) were included. There was no difference in the rate of progression to exudative MNV in the soft and pachydrusen groups (13.3% versus 24.1%, p = 0.38). Pachydrusen, as compared to soft drusen, was associated with polypoidal choroidal vasculopathy subtype (85.7% versus 16.7%, p < 0.01) and the location of exudation was co-localised with soft drusen but not with pachydrusen. There was a higher rate of increase in soft drusen area compared to pachydrusen area (27.7 ± 31.9%/year versus 8.7 ± 12.4%/year respectively, p < 0.01). We found no difference in the proportion of eyes that developed exudative MNV in this study however characterisation of drusen evolution patterns revealed a strong association with exudative MNV subtype.

Ten-Year Progression From Intermediate to Exudative Age-Related Macular Degeneration and Risk Factors: Bundang AMD Cohort Study Report 1

PURPOSE

This study investigated the 10-year incidence of progression from intermediate to exudative age-related macular degeneration (AMD) and identified genetic and environmental factors influencing that progression in the Korean population.

DESIGN

Retrospective, observational cohort study.

METHODS

In total, 632 eyes of 418 patients (age: ≥50 years) with intermediate AMD were enrolled. The incidence of exudative AMD was assessed from color fundus photographs and optical coherence tomography images obtained at baseline and during annual visits. Data regarding lifestyle variables and dietary habits were acquired through comprehensive questionnaires. Genotyping data concerning 3 single nucleotide polymorphisms (SNPs), rs800292 and rs1061170 in the CFH gene and rs10490924 in ARMS2 were also analyzed. The cumulative incidence of exudative changes was estimated using Kaplan-Meier analysis. Associated influential factors were evaluated using univariate and multivariate Cox regression models.

RESULTS

The mean follow-up period was 3.99 ± 2.85 years. The cumulative incidence of progression to exudative AMD was 5.6%, 14.8%, and 28.4% at 2, 5, and 10 years, respectively. Multivariate Cox analysis showed that age (hazard ratio [HR]: 1.041; P = .0393), family history of AMD (HR: 3.175; P = .0184), and pre-existing exudative AMD in the fellow eye (HR: 3.186; P = 5.31 × 10^-5) were positively associated with exudative changes. Regular intake of green tea (HR: 0.632; P = .0475) was associated with a decrease in exudative changes. The ARMS2 SNP rs10490924 (HR: 1.482; P = .0185) showed a significant association with AMD progression.

CONCLUSIONS

The annual progression rate from intermediate to exudative AMD in the Korean population is approximately 2.8%, which is comparable with that for whites. Intake of green tea may be a modifiable protective factor against exudative changes.

Association of Metformin Use With Age-Related Macular Degeneration: A Case-Control Study

Importance

Age-related macular degeneration (AMD), the leading cause of irreversible blindness in older adults, appears to have no effective preventive measures. The common antidiabetic drug metformin has been shown to have protective outcomes in multiple age-associated diseases and may have the potential to protect against the development of AMD.

Objective

To determine whether metformin use is associated with reduced odds of developing AMD.

Design, Setting, and Participants

This case-control study of patients from a nationwide health insurance claims database included a population-based sample of patients. Those aged 55 years and older with newly diagnosed AMD from January 2008 to December 2017 were defined as cases and matched with control participants. Data analyses were completed from June 2019 to February 2020.

Exposures

Dosage of metformin and exposure to other prescribed medications, as identified from outpatient drug claims.

Main Outcomes and Measures

Risk of developing AMD.

Results

A total of 312 404 affected individuals were included (181 817 women [58.2%]). After matching, 312 376 control participants were included (172 459 women [55.2%]; age range, 55 to 107 years). The case group had a slightly higher percentage of participants with diabetes (81 262 participants [26.0%]) compared with the control group (79 497 participants [25.5%]). Metformin use was associated with reduced odds of developing AMD (odds ratio [OR], 0.94 [95% CI, 0.92-0.96]). This association was dose dependent, with low to moderate doses of metformin showing the greatest potential benefit (dosages over 2 years: 1-270 g, OR, 0.91 [95% CI, 0.88-0.94]; 271-600 g, OR, 0.90 [95% CI, 0.87-0.93]; 601-1080 g, OR, 0.95 [95% CI, 0.92-0.98]). Doses of more than 1080 g of metformin over 2 years did not have reduced odds of developing AMD. Both the reduction in odds ratio and the dose-dependent response were preserved in a cohort consisting only of patients with diabetes. Metformin use was associated with a decreased OR of AMD in patients with diabetes without coexisting diabetic retinopathy (OR, 0.93 [95% CI, 0.91-0.95]) but was a risk factor in patients with diabetic retinopathy (OR, 1.07 [95% CI, 1.01-1.15]).

Conclusion and Relevance

In this study, metformin use was associated with reduced odds of developing AMD. This association was dose dependent, with the greatest benefit at low to moderate doses. When looking only at patients with diabetes, we saw a preservation of the dose-dependent decrease in the odds of patients developing AMD. Metformin does not appear to be protective in patients with diabetes and coexisting diabetic retinopathy. This study suggests that metformin may be useful as a preventive therapy for AMD and provides the basis for potential prospective clinical trials.

Comparison of risk allele frequencies of single nucleotide polymorphisms associated with age-related macular degeneration in different ethnic groups

BACKGROUND

The prevalence of age-related macular degeneration (AMD) varies from 6.8 to 18.3% for all forms of AMD and from 0.6 to 2.6% for late AMD according to race, suggesting the existence of genetic differences among races. The purpose of this study was to determine the genetic causes of differences in the prevalence of AMD among individuals of different races.

METHODS

We collected 138 AMD-associated single nucleotide polymorphisms (SNPs) from a genome-wide association studies catalog. Their population-level allele frequencies were derived based on the 1000 Genomes Project and Korean Reference Genome Database. We used Fisher's exact tests to assess whether the effect allele at a given SNP was significantly enriched or depleted in the database.

RESULTS

European, American, and South Asian populations showed similar heatmap patterns, whereas East Asian, and Korean populations had distinct patterns. Korean populations exhibited patterns that were different from those of the other groups; rs5754227 (SYN3), rs1626340 (TGFBR1/COL15A1), rs3750846(ARMS2/HTRA1), and rs9564692 (B3GALTL) were enriched, whereas rs2230199 (C3) and rs73036519 (EXOC3L2/MARK4) were depleted in Koreans; these SNPs are associated with late AMD. The genetic risk score calculated from allele frequencies was not less in East Asians than in Europeans.

CONCLUSION

The prevalence of AMD is lower in Asians than in Europeans. However, our study showed that genetic risk scores in East Asians were similar to those in Europeans, which may explain why the global projected number of people with AMD by 2040 is in largest for East Asians, including Koreans.

Systemic Disease and Ocular Comorbidity Analysis of Geographically Isolated Federally Recognized American Indian Tribes of the Intermountain West

BACKGROUND

The American Indian Navajo and Goshute peoples are underserved patient populations residing in the Four Corners area of the United States and Ibupah, Utah, respectively.

METHODS

We conducted a cross-sectional study of epidemiological factors and lipid biomarkers that may be associated with type II diabetes, hypertension and retinal manifestations in tribal and non-tribal members in the study areas (n = 146 participants). We performed multivariate analyses to determine which, if any, risk factors were unique at the tribal level. Fundus photos and epidemiological data through standardized questionnaires were collected. Blood samples were collected to analyze lipid biomarkers. Univariate analyses were conducted and statistically significant factors at p < 0.10 were entered into a multivariate regression.

RESULTS

Of 51 participants for whom phenotyping was available, from the Four Corners region, 31 had type II diabetes (DM), 26 had hypertension and 6 had diabetic retinopathy (DR). Of the 64 participants from Ibupah with phenotyping available, 20 had diabetes, 19 had hypertension and 6 had DR. Navajo participants were less likely to have any type of retinopathy as compared to Goshute participants (odds ratio (OR) = 0.059; 95% confidence interval (CI) = 0.016-0.223; p < 0.001). Associations were found between diabetes and hypertension in both populations. Older age was associated with hypertension in the Four Corners, and the Navajo that reside there on the reservation, but not within the Goshute and Ibupah populations. Combining both the Ibupah, Utah and Four Corners study populations, being American Indian (p = 0.022), residing in the Four Corners (p = 0.027) and having hypertension (p < 0.001) increased the risk of DM. DM (p < 0.001) and age (p = 0.002) were significantly associated with hypertension in both populations examined. When retinopathy was evaluated for both populations combined, hypertension (p = 0.037) and living in Ibupah (p < 0.001) were associated with greater risk of retinopathy. When combining both American Indian populations from the Four Corners and Ibupah, those with hypertension were more likely to have DM (p < 0.001). No lipid biomarkers were found to be significantly associated with any disease state.

CONCLUSIONS

We found different comorbid factors with retinal disease outcome between the two tribes that reside within the Intermountain West. This is indicated by the association of tribe and with the type of retinopathy outcome when we combined the populations of American Indians. Overall, the Navajo peoples and the Four Corners had a higher prevalence of chronic disease that included diabetes and hypertension than the Goshutes and Ibupah. To the best of our knowledge, this is the first study to conduct an analysis for disease outcomes exclusively including the Navajo and Goshute tribe of the Intermountain West.

Latest Developments in Polypoidal Choroidal Vasculopathy: Epidemiology, Etiology, Diagnosis, and Treatment

Polypoidal choroidal vasculopathy (PCV) is a condition characterized by multiple, recurrent, serosanguineous pigment epithelial detachments, and neurosensory retinal detachments due to abnormal aneurysmal neovascular lesions. It is generally considered as a variant of neovascular age-related macular degeneration, but there are some differences between the clinical presentation, natural history, and treatment response between patients with PCV and typical neovascular age-related macular degeneration patients. Over the past decade, new research and technological advancements have greatly improved our understanding of the PCV disease process and the management of PCV. This review aims to summarize the recent research findings to highlight the epidemiology, pathogenesis, genetics, the application of various diagnostic tools for PCV, and the available treatment options for PCV.

Association of Irregular Pigment Epithelial Detachment in Central Serous Chorioretinopathy with Genetic Variants Implicated in Age-related Macular Degeneration

We evaluated phenotype and genotype correlation of central serous chorioretinopathy (CSC) patients with or without irregular pigment epithelial detachment (PED) on optical coherence tomography (OCT). For CSC, a flat, irregular protrusion of retinal pigment epithelium (RPE) with hyper-reflective sub-RPE fluid on OCT was defined as an irregular PED. Participants were classified into 5 subgroups; (1) total CSC (n = 280) (2) CSC with irregular PED (n = 126) (3) CSC without irregular PED (n = 154) (4) typical choroidal neovascularization (CNV) (n = 203) and (5) polypoidal choroidal vasculopathy (PCV) (n = 135). Ten known major AMD-associated single-nucleotide polymorphisms (SNPs) were analyzed. Age, sex adjusted logistic regression was performed for the association between subgroups. Association analysis between CSC without irregular PED and CNV revealed that significant difference for rs10490924 in ARMS2, rs10737680 in CFH, and marginally significant difference for rs800292 in CFH. Between CSC without irregular PED and PCV, rs10490924, rs10737680, and rs800292 were significantly different. In contrast, CSC with irregular PED and CNV revealed no SNP showing significant difference. Between CSC with irregular PED and PCV, only rs10490924 was significantly different. CSC with irregular PED and CSC without irregular PED revealed significant difference for rs800292, and marginal difference for rs10737680. These findings suggest CSC patients with irregular PED are genetically different from those without irregular PED and may have genetic and pathophysiologic overlap with AMD patients.

Complement Factor I Gene Polymorphism in a Turkish Age-Related Macular Degeneration Population

OBJECTIVE

Evaluation of Complement Factor I (CFI) rs10033900 and rs2285714 polymorphism frequencies in patients with age-related macular degeneration (AMD) and healthy controls in a Turkish population.

METHODS

A total of 111 eyes of 111 AMD patients and 96 eyes of 96 healthy controls, only one eye of individuals, were included in the study; however, 2 patients' and 4 controls' samples were excluded as analyses could not be performed for rs10033900 polymorphism. The AMD patients and control group (>50 years) lacked corneal, lenticular, vitreal opacity. However, these patients did not have any retinal diseases apart from AMD. Venous blood samples of patients were collected. Central macular thickness, subfoveal choroidal thickness (SCT), presence of reticular drusen, epiretinal membrane, and pigment epithelial detachment were investigated using Spectral-Domain Optical Coherence Tomography, and the largest diameter of atrophic areas measured. Drusen properties were documented from fundus photographs. The lesion width was calculated by using fundus fluorescein angiography.

RESULTS

There was no difference between patient and control groups and polymorphism distributions. The frequency of the CT allele was higher in patients with dry-type AMD with retinal pigment epithelial abnormality (p = 0.041). SCT was significantly thinner in TT allele carriers with rs2285714 polymorphism (p = 0.030). No significant relationship was found between the other parameters and polymorphism distributions. Con-clusion: CFI rs10033900 and rs2285714 polymorphisms in a Turkish population were not associated with AMD.

Genetic Epidemiologic Analysis of Hypertensive Retinopathy in an Underrepresented and Rare Federally Recognized Native American Population of the Intermountain West

Understanding disease risk is challenging in multifactorial conditions as it can differ by environment, ethnicity and race. The Confederated Tribes of the Goshute Reservation are one of the most isolated populations in the United States. Retinal changes are a reliable indicator for systemic disease. We conducted a cross-sectional study to identify correlations between genetic data and epidemiological risk factors for blinding retinal disease in this tribe. As part of the "Supporting Prediction and Prevention Blindness Project (SPBPP)" in the Native American Population of the Intermountain West, we found that hypertensive retinopathy was the most prevalent retinal disease. We found that forty-two percent of the Goshute population was affected. Blood samples, fundus photos and intraocular pressure were obtained for all participants. In addition, a standardized questionnaire was administered. DNA and total cholesterol, HDL, LDL, VLDL, triglycerides and HbA1c were also evaluated. Our study interrogated genetic variants from the PAGE study (ARMS2 rs10490924, CFH rs800292, rs1061170) and additional studies that looked at previously associated genetic variants with retinal disease associated with cardiovascular disease. We conducted univariate and multivariate logistic regression in Stata v15.0. We found an association between hypertriglyceridemia and HTR (adjp = .05) within the Goshute population. To the best of our knowledge, this is the first study to demonstrate the prevalence of hypertensive retinopathy in a Native American population. Moreover, our study is the first to demonstrate an independently predictive relationship between hypertriglyceridemia and hypertensive retinopathy in an American Indian population. This study furthers our knowledge about prevalent blinding eye disease within the most geographically isolated federally recognized native United States American tribe, for which nothing has been published with respect to any disease. Although, this study furthers our understanding about the prevalence of genetic epidemiological risk factors within this population, it has greater implications for the screening of blinding diseases in underserved populations in general. This study can inform public health on planning and delivering of quality, accessible and relevant care to this population.

Analysis of genetic polymorphisms for age-related macular degeneration (AMD) in Chinese Tujia ethnic minority group

Background

Age-related macular degeneration (AMD) can cause vision loss or blindness in elderly. The associations between single nucleotide polymorphism (SNP) and AMD in Chinese Tujia ethnic minority group are still unclear.

Methods

A total of 2122 Tujia volunteers were recruited and 197 of them were diagnosed with AMD (either dry or wet type).Then the blood specimens of these 197 AMD patients and 404 controls from the remaining 1925 normal Tujia volunteers were collected to detect the frequencies of 39 chosen SNPs. The Bonferroni method was used to correct the P values from the Fisher’s exact test.

Results

The mean age of the 197 AMD patients(113 males and 84 females) was 68.4197 years old. No significant differences in allelic and genotypic frequencies were found for all the 39 SNPs between the patients and controls. However, weak correlations between 10 SNPs (CFH rs1329428 TT genotype, CFH rs3753394 CC genotype and T allele, CFH rs1410996 AA genotype, CFH rs800292 AA genotype, CFH rs800292 A allele, VEGF rs833061 TT genotype and C allele, VEGF rs2010963 CG genotype, VEGFR2 rs1531289 TT genotype, ARMS2 rs10490924 TT genotype, KCTD10 rs238104 GC genotype, rs1531289 T allele and ARMS2 rs10490924 T allele) and AMD were shown.

Conclusions

The effects of 39 SNPs have found no associations with the morbidity of AMD in Chinese Tujia ethnic minority group.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0756-4) contains supplementary material, which is available to authorized users.

Thickness of retina and choroid in the elderly population and its association with Complement Factor H polymorphism: KLoSHA Eye study

PURPOSE

To analyze the associations of retinal and choroidal thickness on enhanced-depth imaging optical coherence tomography (EDI-OCT) with clinical, ophthalmic and genetic factors in the normal elderly population (aged 65 years or older).

METHODS

In this prospective, population-based cohort study, people aged 65 years or older were enrolled in the baseline study of the Korean Longitudinal Study on Health and Aging (KLoSHA) Eye Study. All participants underwent spectral domain-OCT scan using the EDI technique. A topographic map of the retina was obtained and subfoveal choroidal thickness (SFCT) was measured manually. Blood samples from all subjects were genotyped for major age-related macular degeneration (AMD)-associated single nucleotide polymorphisms (SNPs) the major AMD-associated SNPs; CFH Y402H rs1061170, CFH I62V rs800292, ARMS2 A69S rs10490924. A statistical analysis was conducted to compare the retinal thickness, choroidal thickness, and AMD risk genotypes.

RESULTS

Among the three hundred eighty people enrolled, the mean age was 76.6 years (range 65-99 years). Factors that showed correlation with either tomographic retinal parameters, retinal nerve fiber layer, or SFCT, were age and gender. Significant age-related decrease in thickness was observed in the RNFL, mean central thickness (MCT) and SFCT. Gender differences existed in central foveolar thickness (CFT) and MCT, where it was thicker in men. While chorioretinal parameters were not related with other genotypes, CFH rs1061170 risk genotype was significantly associated with thin SFCT. The group containing the AMD- risk allele (CT) had a 14.7% reduction in the SFCT compared to the non-risk TT group.

CONCLUSIONS

In addition to the well-known association with AMD, CFH rs1061170 is a significant genetic risk factor associated with choroidal thinning in normal eyes of the elderly population. Such findings may provide further insight into the pathogenesis of age-related macular degeneration as well as normal aging. In addition, our study provides the first normative data on retinal and choroidal thickness in population-based aged groups with a mean age over seventy-five.

Prevalence and Risk Factors for Polypoidal Choroidal Vasculopathy in a General Japanese Population: The Hisayama Study

PURPOSE

To estimate the prevalence and risk factors for polypoidal choroidal vasculopathy (PCV) in a general Japanese population.

METHODS

This population-based, cross-sectional study was conducted in 2007 with subjects from the Hisayama Study. Of the 3,648 residents in Hisayama, Japan, 2,663 who were ≥ 50 years old were enrolled in this study. The characteristics of PCV were determined by fundus examination or based on indocyanine green and fluorescein angiographic findings. We evaluated the contributions of the risk factors for PCV.

RESULTS

Among the 207 participants with age-related macular degeneration (AMD), 174 (6.5%) had early AMD, and 33 (1.2%) had late AMD, including 10 participants with PCV (0.4%). Male and smoking habit were significant risk factors for the development of PCV.

CONCLUSIONS

The prevalence of PCV is higher among Japanese subjects than Caucasians in Western countries. Male gender and smoking habit were significant risk factors for PCV in a general Japanese population.

Association of coding and UTR variants in the known regions with wet age-related macular degeneration in Han Chinese population

Age-related macular degeneration (AMD) is the leading cause worldwide of severe visual impairment among people older than 55 years of age. This study aimed to investigate the genetic association between coding and untranslated region (UTR) variants in previously reported loci and exudative age-related macular degeneration (wet AMD) in a Han Chinese population. Using our previously published whole exome sequencing dataset of 349 wet AMD patients and 1253 controls, we searched for associations between coding and UTR variants of the 72 genes located within the 47 reported wet AMD loci regions. From these, 25 variants in 18 of the 72 genes with P < 10 × 10^-3 were selected for the first replication of Sequenom mass-array genotyping in 885 wet AMD subjects and 562 controls. Next, four SNPs were selected for further validation by SNaPshot genotyping in a third Chinese cohort with 456 wet AMD subjects and 211 controls. As a result, we identified two new potential coding and UTR variant SNPs (rs189132250 in BBX located in 3q12.1 and rs144351944 in FILIP1L located in 3q12.1) that showed weak associations with wet AMD in the Han Chinese population. These findings provide new information regarding the coding and UTR variants of the known wet AMD loci in the studied Chinese cohort.

A comparison of risk factors for age-related macular degeneration and polypoidal choroidal vasculopathy in Chinese patients

PURPOSE

Neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) are important vision-threatening diseases worldwide. For effective treatment, the risk factors for the diseases merit investigation. This study aimed to compare the risk factors for nAMD vs. PCV in Chinese patients.

METHODS

A total of 946 participants were recruited in this case-control study, including 281 patients with nAMD, 306 patients with PCV, and 359 controls. All participants underwent comprehensive ophthalmic examinations. Information on risk factors were collected by questionnaire. Multivariate logistic regression analyses were performed to investigate the difference in risk factors between nAMD and PCV. In a subgroup of subjects, serum lipid data were obtained and analyzed.

RESULTS

Risk factors for nAMD included older age (OR 1.03, P = 0.001), male gender (OR 1.55, P = 0.020), asthma (OR 2.50, P = 0.028), smoking (OR 1.92, P = 0.001), and family history (OR 6.82, P = 0.001), while smoking (OR 1.67, P = 0.013) was the only risk factor for PCV. Compared to patients with PCV, patients with nAMD were more likely to be older and suffer from hyperlipidemia, coronary artery disease, rheumatism, and tumor. Interestingly, higher levels of high-density lipoprotein were positively associated with PCV in the subgroup analysis (OR 7.74, P = 0.011). Besides, results were quite different between the combination of patients with nAMD and PCV and patients with nAMD or PCV alone.

CONCLUSIONS

The risk factors for nAMD and PCV is varying with the exception of smoking. Our findings suggest that different strategies might be applied in the clinical management and scientific research on nAMD and PCV.

Myopia in Chinese families shows linkage to 10q26.13

Purpose

To determine genetic linkage between myopia and Han Chinese patients with a family history of the disease.

Methods

One hundred seventy-six Han Chinese patients from 34 extended families were given eye examinations, and mean spherical equivalent (MSE) in diopters (D) was calculated by adding the spherical component of the refraction to one-half the cylindrical component and taking the average of both eyes. The MSE was converted to a binary phenotype, where all patients with an MSE of -1.00 D or less were coded as affected. Unaffected individuals had an MSE greater than 0.00 D (ages 21 years and up), +1.50 (ages 11-20), or +2.00 D (ages 6-10 years). Individuals between the given upper threshold and -1.00 were coded as unknown. Patients were genotyped on an exome chip. Three types of linkage analyses were performed: single-variant two-point, multipoint, and collapsed haplotype pattern (CHP) variant two-point.

Results

The CHP variant two-point results identified a significant peak (heterogeneity logarithm of the odds [HLOD] = 3.73) at 10q26.13 in TACC2. The single-variant two-point and multipoint analyses showed highly suggestive linkage to the same region. The single-variant two-point results identified 25 suggestive variants at HTRA1, also at 10q26.13.

Conclusions

We report a significant genetic linkage between myopia and Han Chinese patients at 10q26.13. 10q26.13 contains several good candidate genes, such as TACC2 and the known age-related macular degeneration gene HTRA1. Targeted sequencing of the region is planned to identify the causal variant(s).

Prevalence and treatment patterns of ranibizumab and photodynamic therapy in a tertiary care setting in Malaysia

AIM

To describe the prevalence and changes in treatment patterns of ranibizumab and photodynamic therapy (PDT) among retinal disease patients who attended the Ophthalmology Clinic in the tertiary care Hospital Selayang from 2010 to 2014.

METHODS

Study subjects were recruited retrospectively using the Electronic Medical Record (EMR) database software in Hospital Selayang. Demographic data, medical history, diagnostic procedure, treatments and diagnosis of patients were recorded.

RESULTS

The five-year analysis included 821 patients with a mean age of 65.9±11.73y. Overall, there were a higher number of males (63.1%) and a higher number of Chinese (47.4%) patients. Among the 821 patients, 62.9% received ranibizumab injection followed by 19.2% PDT therapy and 17.9% had ranibizumab combined with PDT therapy. Age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) were the most common retinal eye diseases reported, recording prevalence of 25.0% and 45.6%, respectively. The trend in ranibizumab treatment was reported to increase while PDT showed a decrease in trend from year 2010 to 2014. In terms of treatment, following multiple logistic regression, AMD was associated with the subjects being more likely to have received ranibizumab monotherapy (P<0.001) while PCV was associated with more likely to have received PDT (P<0.001) and PDT combined with ranibizumab therapy (P<0.001).

CONCLUSION

The tertiary care setting in Malaysia is consistent with management of patients from other countries whereby ranibizumab is the most common treatment given to patients with AMD, while PCV patients most commonly receive PDT and ranibizumab combined with PDT therapy.

Polypoidal Choroidal Vasculopathy

PURPOSE OF REVIEW

The goal of this paper is to review the recent literature of polypoidal choroidal vasculopathy (PCV) and provide an update on the epidemiology, pathophysiology, clinical findings, and management.

RECENT FINDINGS

Although indocyanine-green angiography (ICGA) is still the gold standard for diagnosis of PCV, the use of en face optical coherence tomography (OCT) and OCT angiography are useful tools in the diagnosis of PCV. Studies demonstrate superior treatment outcomes with combination photodynamic therapy (PDT) and anti-vascular endothelial growth factor (VEGF) therapy.

SUMMARY

PCV is a disease most commonly in Asians and African-Americans and presents with an orange-red nodule in the macula or the peripapillary region. While ICGA remains the most accurate method to diagnose PCV, newer non-invasive imaging modalities (eg. OCT-A and en face OCT) can be used to identify PCV lesions. The combination of PDT and anti-VEGF therapy is superior to either monotherapy. Future studies of OCT modalities and other anti-VEGF agents will be important in guiding PCV diagnosis and management, respectively.

Systemic, Ocular and Genetic Risk Factors for Age-related Macular Degeneration and Polypoidal Choroidal Vasculopathy in Singaporeans

To examine the association of systemic, ocular and genetic risk factors in neovascular age-related macular degeneration (nAMD) in a large cohort of Asian patients, and to further compare risk factors between those with typical AMD and polypoidal choroidal vasculoapthy (PCV) subtypes. We recruited 456 cases and 1,824 controls matched for age, gender and ethnicity. Data on systemic and ocular risk factors were collected on questionnaires. In a subgroup of subjects, we included genetic data on four AMD-associated single nucleotide polymorphisms (SNPs). Risk factors for nAMD and subtypes were analyzed. Systemic risk factors for nAMD included older age, male gender, higher BMI and higher HDL-cholesterol. Ocular risk factors included pseudophakic and shorter axial length. Risk factors common to both typical AMD and PCV subtypes included age, BMI and HDL-cholesterol. Shorter axial length was only associated with PCV, while male gender and pseudophakia were only associated with typical AMD. In the subgroup with genotype data, ARMS2 rs10490924 and CFH rs800292 were associated with nAMD. None of the risk factors were significantly different between PCV and typical AMD. Systemic, ocular and genetic risk factors were largely similar for typical AMD and PCV subtypes in this Asian population based in Singapore.

C3a Increases VEGF and Decreases PEDF mRNA Levels in Human Retinal Pigment Epithelial Cells

Complement activation, specifically complement 3 (C3) activation and C3a generation, contributes to an imbalance between angiogenic stimulation by vascular endothelial growth factor (VEGF) and angiogenic inhibition by pigment epithelial derived factor (PEDF), leading to pathological angiogenesis. This study aimed to investigate the effects of C3a and small interfering RNA (siRNA) targeting C3 on the levels of VEGF and PEDF mRNAs in human retinal pigment epithelial (RPE) cells. ARPE-19 cells were cultured in the presence of exogenous C3a at 0.1 μM and 0.3 μM C3a for 24, 48, and 72 hours. 0.1 pmol/μL duplexes of siRNA targeting C3 were applied for C3a inhibition by transfecting ARPE-19 cells for 48 hours. RT-PCR was performed to examine the level of VEGF and PEDF mRNA. A random siRNA duplex was set for control siRNA. Results demonstrated that exogenous C3a significantly upregulated VEGF and downregulated PEDF mRNA levels in cultured ARPE-19 cells, and siRNA targeting C3 transfection reversed the above changes, significantly reducing VEGF and enhancing PEDF mRNAs level in ARPE-19 cells compared to the control. The present data provided evidence that reducing C3 activation can decreases VEGF and increase PEDF mRNA level in RPE and may serve as a potential therapy in pathological angiogenesis.

Proteomics-based identification and validation of novel plasma biomarkers phospholipid transfer protein and mannan-binding lectin serine protease-1 in age-related macular degeneration

Age-related macular degeneration (AMD) is a major cause of severe, progressive visual loss among the elderly. There are currently no established serological markers for the diagnosis of AMD. In this study, we carried out a large-scale quantitative proteomics analysis to identify plasma proteins that could serve as potential AMD biomarkers. We found that the plasma levels of phospholipid transfer protein (PLTP) and mannan-binding lectin serine protease (MASP)-1 were increased in AMD patients relative to controls. The receiver operating characteristic curve based on data from an independent set of AMD patients and healthy controls had an area under the curve of 0.936 for PLTP and 0.716 for MASP-1, revealing excellent discrimination between the two groups. A proteogenomic combination model that incorporated PLTP and MASP-1 along with two known risk genotypes of age-related maculopathy susceptibility 2 and complement factor H genes further enhanced discriminatory power. Additionally, PLTP and MASP-1 mRNA and protein expression levels were upregulated in retinal pigment epithelial cells upon exposure to oxidative stress in vitro. These results indicate that PLTP and MASP-1 can serve as plasma biomarkers for the early diagnosis and treatment of AMD, which is critical for preventing AMD-related blindness.

Incidence Rate of Massive Submacular Hemorrhage and its Risk Factors in Polypoidal Choroidal Vasculopathy

PURPOSE

To investigate the incidence rate of massive submacular hemorrhage (SMH) in patients with polypoidal choroidal vasculopathy (PCV) and analyze the associated risk factors.

DESIGN

Retrospective cohort study.

METHODS

Patients diagnosed with PCV from May 2003 to May 2014 were included. Two hundred forty-five eyes of 245 patients were enrolled. The time between the initial visit to the clinic with subjective visual symptoms and the date of massive SMH was recorded. SMH larger than 4 disc diameters was defined as massive SMH. Age; hypertension; visual acuity (VA); indocyanine green angiography findings, including the greatest linear dimension, largest polyp size, and PCV type (cluster vs non-cluster); and treatment methods were reviewed for risk factor analysis using Kaplan-Meier survival and Cox regression analyses.

RESULTS

The incidence rate of massive SMH within 1 year after the initial visit was 2.45%. Massive SMH occurred within 3, 5, and 10 years after the first visit in 6.17%, 11.09%, and 29.85% of patients, respectively. Cox regression analysis revealed that the cluster type of PCV was significantly associated with massive SMH (hazard ratio [HR], 3.418; P = .003). Photodynamic therapy followed by anti-vascular endothelial growth factor injection lowered the risk of massive SMH (HR = .242; P = .047]. Final VA in eyes with massive SMH was significantly lower than that in patients without massive SMH (1.34 ± 0.66 vs 0.63 ± 0.53 logMAR; P < .001).

CONCLUSIONS

Patients with PCV who develop massive SMH experience severe vision loss. The incidence rate of massive SMH in PCV increases with time. The cluster type of polyp in PCV is a significant risk factor for massive SMH.

Risk factors and biomarkers of age-related macular degeneration

A biomarker can be a substance or structure measured in body parts, fluids or products that can affect or predict disease incidence. As age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, much research and effort has been invested in the identification of different biomarkers to predict disease incidence, identify at risk individuals, elucidate causative pathophysiological etiologies, guide screening, monitoring and treatment parameters, and predict disease outcomes. To date, a host of genetic, environmental, proteomic, and cellular targets have been identified as both risk factors and potential biomarkers for AMD. Despite this, their use has been confined to research settings and has not yet crossed into the clinical arena. A greater understanding of these factors and their use as potential biomarkers for AMD can guide future research and clinical practice. This article will discuss known risk factors and novel, potential biomarkers of AMD in addition to their application in both academic and clinical settings.

Age-related macular degeneration and polypoidal choroidal vasculopathy in Asians

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in elderly people globally. It is estimated that there will be more Asians with AMD than the rest of the world combined by 2050. In Asian populations, polypoidal choroidal vasculopathy (PCV) is a common subtype of exudative AMD, while choroidal neovascularization secondary to AMD (CNV-AMD) is the typical subtype in Western populations. The two subtypes share many common clinical features and risk factors, but also have different epidemiological and clinical characteristics, natural history and treatment outcomes that point to distinct pathophysiological processes. Recent research in the fields of genetics, proteomics and imaging has provided further clarification of differences between PCV and CNV-AMD. Importantly, these differences have manifested as disparity in response to intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) treatment between PCV and CNV-AMD, emphasizing the need for accurate diagnosis of PCV and in distinguishing PCV from CNV-AMD, particularly in Asian patients. Current clinical trials of intravitreal anti-VEGF therapy and photodynamic therapy will provide clearer perspectives of evidence-based management of PCV and may lead to paradigm shifts in therapeutic strategies away from those currently employed in the treatment of CNV-AMD. Further research is needed to clarify the relative contribution of specific pathways in inflammation, complement activation, extracellular matrix dysregulation, lipid metabolism and angiogenesis to the pathogenesis of PCV. Findings from this research, together with improved diagnostic technology and new therapeutics, will facilitate more optimal management of Asian AMD.

Effect of High-Density Lipoprotein Metabolic Pathway Gene Variations and Risk Factors on Neovascular Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy in China

Purpose

To investigate the effect of genetic variants in the high-density lipoprotein (HDL) metabolic pathway and risk factors on neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) in China.

Methods

A total of 742 Chinese subjects, including 221 controls, 230 cases with nAMD, and 291 cases with PCV, were included in the present study. Five single nucleotide polymorphisms (SNPs) from three genes in the HDL metabolic pathway (HDLMP) including cholesteryl ester transfer protein (CETP), hepatic lipase (LIPC) and lipoprotein lipase (LPL) were genotyped in all study subjects with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Risk factors including gender, hypertension, hyperlipidemia, diabetes mellitus, and coronary artery disease were identified. Chi-square tests or Fisher’s exact tests were applied to discover associations between SNPs and risk factors for PCV and nAMD. Gene-gene interactions and gene-environment interactions were evaluated by the multifactor-dimensionality reduction (MDR) method.

Results

CETP rs3764261 were significantly associated with an increased risk for PCV (odds ratio (OR) = 1.444, P = 0.0247). LIPC rs1532085 conferred an increased risk for PCV (OR = 1.393, P = 0.0094). We found no association between PCV and LPL rs12678919, LIPC rs10468017 or CETP rs173539. No association was found between five SNPs with nAMD. Regarding risk factors, females were found to have significantly decreased risks for both PCV and nAMD (P = 0.006 and 0.001, respectively). Coronary artery disease (CAD) was a risk factor in PCV patients but played a protective role in nAMD patients. Hyperlipidemia was associated with PCV but not with nAMD. Neither hypertension nor diabetes mellitus was associated with PCV or nAMD. The MDR analysis revealed that a three-locus model with rs12678919, rs1532085, and gender was the best model for nAMD, while a five-locus model consisting of rs10468017, rs3764261, rs1532085, gender, and hyperlipidemia was best for PCV.

Conclusion

Our large-sample study suggested that CETP rs3764261 conferred an increased risk for PCV. We also first found the association between rs1532085 and PCV. The result of present study also showed that gender and CAD are associated with PCV and nAMD. Significant association was found between hyperlipidemia and PCV but not nAMD.