Biomaterial engineering strategies for modeling the Bruch's membrane in age-related macular degeneration

Age-related macular degeneration,a multifactorial inflammatory degenerative retinal disease,ranks as the leading cause of blindness in the elderly.Strikingly,there is a scarcity of curative therapies,especially for the atrophic advanced form of age-related macular degeneration,likely due to the lack of models able to fully recapitulate the native structure of the outer blood retinal barrier,the prime to rget tissue of age-related macular degeneration.Standard in vitro systems rely on 2D monocultures unable to adequately reproduce the structure and function of the outer blood retinal barrier,integrated by the dynamic interaction of the retinal pigment epithelium,the Bruch's membrane,and the underlying choriocapillaris.The Bruch's membrane provides structu ral and mechanical support and regulates the molecular trafficking in the outer blood retinal barrier,and therefo re adequate Bruch's membrane-mimics are key for the development of physiologically relevant models of the outer blood retinal barrie r.In the last years,advances in the field of biomaterial engineering have provided novel approaches to mimic the Bruch's membrane from a variety of materials.This review provides a discussion of the integrated properties and function of outer blood retinal barrier components in healt hy and age-related macular degeneration status to understand the requirements to adequately fabricate Bruch's membrane biomimetic systems.Then,we discuss novel materials and techniques to fabricate Bruch's membrane-like scaffolds for age-related macular degeneration in vitro modeling,discussing their advantages and challenges with a special focus on the potential of Bruch's membrane-like mimics based on decellularized tissue.

Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy

Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecular underpinnings of their development.This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches,focusing on the activation of transcription factor EB.Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies,such as exercise,calorie restriction,rapamycin,and metformin,in patients and animal models of these common retinal diseases.The review critically assesses the role of transcription factor EB in retinal biology during aging,its neuroprotective effects,and its therapeutic potential for retinal disorders.The impact of transcription factor EB on retinal aging is cell-specific,influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways.In vascular endothelial cells,transcription factor EB controls important processes,including endothelial cell proliferation,endothelial tube formation,and nitric oxide levels,thereby influencing the inner blood-retinal barrier,angiogenesis,and retinal microvasculature.Additionally,transcription factor EB affects vascular smooth muscle cells,inhibiting vascular calcification and atherogenesis.In retinal pigment epithelial cells,transcription factor EB modulates functions such as autophagy,lysosomal dynamics,and clearance of the aging pigment lipofuscin,thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization.These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis,neuronal synapse plasticity,energy metabolism,microvasculature,and inflammation,ultimately offering protection against retinal aging and diseases.The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases.Therefore,it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects.

Subretinal fibrosis secondary to neovascular age-related macular degeneration:mechanisms and potential therapeutic targets

Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration.It causes local damage to photoreceptors,retinal pigment epithelium,and choroidal vessels,which leads to permanent central vision loss of patients with neovascular age-related macular degeneration.The pathogenesis of subretinal fibrosis is complex,and the underlying mechanisms are largely unknown.Therefore,there are no effective treatment options.A thorough understanding of the pathogenesis of subretinal fibrosis and its related mechanisms is important to elucidate its complications and explore potential treatments.The current article reviews several aspects of subretinal fibrosis,including the current understanding on the relationship between neovascular age-related macular degeneration and subretinal fibrosis;multimodal imaging techniques for subretinal fibrosis;animal models for studying subretinal fibrosis;cellular and non-cellular constituents of subretinal fibrosis;pathophysiological mechanisms involved in subretinal fibrosis,such as aging,infiltration of macrophages,different sources of mesenchymal transition to myofibroblast,and activation of complement system and immune cells;and several key molecules and signaling pathways participating in the pathogenesis of subretinal fibrosis,such as vascular endothelial growth factor,connective tissue growth factor,fibroblast growth factor 2,platelet-derived growth factor and platelet-derived growth factor receptor-β,transforming growth factor-βsignaling pathway,Wnt signaling pathway,and the axis of heat shock protein 70-Toll-like receptors 2/4-interleukin-10.This review will improve the understanding of the pathogenesis of subretinal fibrosis,allow the discovery of molecular targets,and explore potential treatments for the management of subretinal fibrosis.

Regulatory factors of Nrf2 in age-related macular degeneration pathogenesis

Age-related macular degeneration(AMD)is a complicated disease that causes irreversible visual impairment.Increasing evidences pointed retinal pigment epithelia(RPE)cells as the decisive cell involved in the progress of AMD,and the function of anti-oxidant capacity of PRE plays a fundamental physiological role.Nuclear factor erythroid 2 related factor 2(Nrf2)is a significant transcription factor in the cellular anti-oxidant system as it regulates the expression of multiple anti-oxidative genes.Its functions of protecting RPE cells against oxidative stress(OS)and ensuing physiological changes,including inflammation,mitochondrial damage and autophagy dysregulation,have already been elucidated.Understanding the roles of upstream regulators of Nrf2 could provide further insight to the OS-mediated AMD pathogenesis.For the first time,this review summarized the reported upstream regulators of Nrf2 in AMD pathogenesis,including proteins and miRNAs,and their underlying molecular mechanisms,which may help to find potential targets via regulating the Nrf2 pathway in the future research and further discuss the existing Nrf2 regulators proved to be beneficial in preventing AMD.

HCSP-Net:A Novel Model of Age-Related Macular Degeneration Classification Based on Color Fundus Photography

Age-related macular degeneration(AMD)ranks third among the most common causes of blindness.As the most conventional and direct method for identifying AMD,color fundus photography has become prominent owing to its consistency,ease of use,and good quality in extensive clinical practice.In this study,a convolutional neural network(CSPDarknet53)was combined with a transformer to construct a new hybrid model,HCSP-Net.This hybrid model was employed to tri-classify color fundus photography into the normal macula(NM),dry macular degeneration(DMD),and wet macular degeneration(WMD)based on clinical classification manifestations,thus identifying and resolving AMD as early as possible with color fundus photography.To further enhance the performance of this model,grouped convolution was introduced in this study without significantly increasing the number of parameters.HCSP-Net was validated using an independent test set.The average precision of HCSPNet in the diagnosis of AMD was 99.2%,the recall rate was 98.2%,the F1-Score was 98.7%,the PPV(positive predictive value)was 99.2%,and the NPV(negative predictive value)was 99.6%.Moreover,a knowledge distillation approach was also adopted to develop a lightweight student network(SCSP-Net).The experimental results revealed a noteworthy enhancement in the accuracy of SCSP-Net,rising from 94%to 97%,while remarkably reducing the parameter count to a quarter of HCSP-Net.This attribute positions SCSP-Net as a highly suitable candidate for the deployment of resource-constrained devices,which may provide ophthalmologists with an efficient tool for diagnosing AMD.

Association of age at diagnosis of diabetes with subsequent risk of age-related ocular diseases and vision acuity

BACKGROUND The importance of age on the development of ocular conditions has been reported by numerous studies.Diabetes may have different associations with different stages of ocular conditions,and the duration of diabetes may affect the development of diabetic eye disease.While there is a dose-response relationship between the age at diagnosis of diabetes and the risk of cardiovascular disease and mortality,whether the age at diagnosis of diabetes is associated with incident ocular conditions remains to be explored.It is unclear which types of diabetes are more predictive of ocular conditions.AIM To examine associations between the age of diabetes diagnosis and the incidence of cataract,glaucoma,age-related macular degeneration(AMD),and vision acuity.METHODS Our analysis was using the UK Biobank.The cohort included 8709 diabetic participants and 17418 controls for ocular condition analysis,and 6689 diabetic participants and 13378 controls for vision analysis.Ocular diseases were identified using inpatient records until January 2021.Vision acuity was assessed using a chart.RESULTS During a median follow-up of 11.0 years,3874,665,and 616 new cases of cataract,glaucoma,and AMD,respectively,were identified.A stronger association between diabetes and incident ocular conditions was observed where diabetes was diagnosed at a younger age.Individuals with type 2 diabetes(T2D)diagnosed at<45 years[HR(95%CI):2.71(1.49-4.93)],45-49 years[2.57(1.17-5.65)],50-54 years[1.85(1.13-3.04)],or 50-59 years of age[1.53(1.00-2.34)]had a higher risk of AMD independent of glycated haemoglobin.T2D diagnosed<45 years[HR(95%CI):2.18(1.71-2.79)],45-49 years[1.54(1.19-2.01)],50-54 years[1.60(1.31-1.96)],or 55-59 years of age[1.21(1.02-1.43)]was associated with an increased cataract risk.T2D diagnosed<45 years of age only was associated with an increased risk of glaucoma[HR(95%CI):1.76(1.00-3.12)].HRs(95%CIs)for AMD,cataract,and glaucoma associated with type 1 diabetes(T1D)were 4.12(1.99-8.53),2.95(2.17-4.02),and 2.40(1.09-5.31),respectively.In multivariable-adjusted analysis,individuals with T2D diagnosed<45 years of age[β95%CI:0.025(0.009,0.040)]had a larger increase in LogMAR.Theβ(95%CI)for LogMAR associated with T1D was 0.044(0.014,0.073).CONCLUSION The younger age at the diagnosis of diabetes is associated with a larger relative risk of incident ocular diseases and greater vision loss.

Age-related hearing loss accelerates the decline in fast speech comprehension and the decompensation of cortical network connections

Patients with age-related hearing loss face hearing difficulties in daily life.The causes of age-related hearing loss are complex and include changes in peripheral hearing,central processing,and cognitive-related abilities.Furthermore,the factors by which aging relates to hearing loss via changes in audito ry processing ability are still unclear.In this cross-sectional study,we evaluated 27 older adults(over 60 years old) with age-related hearing loss,21 older adults(over 60years old) with normal hearing,and 30 younger subjects(18-30 years old) with normal hearing.We used the outcome of the uppe r-threshold test,including the time-compressed thres h old and the speech recognition threshold in noisy conditions,as a behavioral indicator of auditory processing ability.We also used electroencephalogra p hy to identify presbycusis-related abnormalities in the brain while the participants were in a spontaneous resting state.The timecompressed threshold and speech recognition threshold data indicated significant diffe rences among the groups.In patients with age-related hearing loss,information masking(babble noise) had a greater effect than energy masking(speech-shaped noise) on processing difficulties.In terms of resting-state electroencephalography signals,we observed enhanced fro ntal lobe(Brodmann’s area,BA11) activation in the older adults with normal hearing compared with the younger participants with normal hearing,and greater activation in the parietal(BA7) and occipital(BA19) lobes in the individuals with age-related hearing loss compared with the younger adults.Our functional connection analysis suggested that compared with younger people,the older adults with normal hearing exhibited enhanced connections among networks,including the default mode network,sensorimotor network,cingulo-opercular network,occipital network,and frontoparietal network.These results suggest that both normal aging and the development of age-related hearing loss have a negative effect on advanced audito ry processing capabilities and that hearing loss accele rates the decline in speech comprehension,especially in speech competition situations.Older adults with normal hearing may have increased compensatory attentional resource recruitment represented by the to p-down active listening mechanism,while those with age-related hearing loss exhibit decompensation of network connections involving multisensory integration.

Oxidative stress in retinal pigment epithelium degeneration:from pathogenesis to therapeutic targets in dry age-related macular degeneration

Age-related macular degeneration is a primary cause of blindness in the older adult population. Past decades of research in the pathophysiology of the disease have resulted in breakthroughs in the form of anti-vascular endothelial growth factor therapies against neovascular age-related macular degeneration;however, effective treatment is not yet available for geographical atrophy in dry agerelated macular degeneration or for preventing the progression from early or mid to the late stage of age-related macular degeneration. Both clinical and experimental investigations involving human agerelated macular degeneration retinas and animal models point towards the atrophic alterations in retinal pigment epithelium as a key feature in age-related macular degeneration progression. Retinal pigment epithelium cells are primarily responsible for cellular-structural maintenance and nutrition supply to keep photoreceptors healthy and functional. The retinal pigment epithelium constantly endures a highly oxidative environment that is balanced with a cascade of antioxidant enzyme systems regulated by nuclear factor erythroid-2-related factor 2 as a main redox sensing transcription factor. Aging and accumulated oxidative stress triggers retinal pigment epithelium dysfunction and eventually death. Exposure to both environmental and genetic factors aggravates oxidative stress damage in aging retinal pigment epithelium and accelerates retinal pigment epithelium degeneration in age-related macular degeneration pathophysiology. The present review summarizes the role of oxidative stress in retinal pigment epithelium degeneration, with potential impacts from both genetic and environmental factors in age-related macular degeneration development and progression. Potential strategies to counter retinal pigment epithelium damage and protect the retinal pigment epithelium through enhancing its antioxidant capacity are also discussed, focusing on existing antioxidant nutritional supplementation, and exploring nuclear factor erythroid-2-related factor 2 and its regulators including REV-ERBα as therapeutic targets to protect against age-related macular degeneration development and progression.

Volumetric fluid analysis of fixed monthly anti-VEGF treatment in patients with neovascular age-related macular degeneration

·AIM:To evaluate visual outcomes and changes in fluid after administering monthly anti-vascular endothelial growth factor(VEGF)injections to treat neovascular agerelated macular degeneration(n AMD)with subretinal fluid(SRF)and pigment epithelial detachment(PED).·METHODS:This prospective study included eyes with n AMD previously treated with as-needed anti-VEGF injections.The patients were treated with six monthly intravitreal injections of ranibizumab.Quantitative volumetric segmentation analyses of the SRF and PED were performed.The main outcome measures included best-corrected visual acuity(BCVA),and SRF and PED volumes.·RESULTS:Twenty eyes of 20 patients were included in this study.At the 6-month follow-up,BCVA and PED volume did not change significantly(P=0.110 and 0.999,respectively)but the mean SRF volume decreased from 0.53±0.82 mm3 at baseline to 0.08±0.23 mm3(P=0.002).The absorption rate of the SRF volume was negatively correlated with the duration of previous antiVEGF treatment(P=0.029).Seven of the 20 eyes(35%)showed a fluid-free macula and significant improvement in BCVA(P=0.036)by month 6.·CONCLUSION:Quantifying the SRF can precisely determine the patient’s responsiveness to anti-VEGF treatment of n AMD.

Aberrant expression of COL4A1 in age-related cataract and its effect on cell proliferation,apoptosis and gene expression changes

AIM:To evaluate the regulation of the aberrant expression of collagen typeⅣalpha 1 chain(COL4A1)in the development of age-related cataract(ARC).METHODS:Quantitative reverse transcription-polymerase chain reaction(qRT-PCR)and Western blot analysis were employed to evaluate the expression of COL4A1 in ARC patients and healthy controls.The proliferation,apoptosis,cell cycle and epithelial-mesenchymal transition(EMT)of human lens epithelial cell(HLE-B3)were further analyzed under the condition of COL4A1 gene silence.Alteration of gene expression at mRNA level after knockdown COL4A1 were also evaluated by qRT-PCR on HLE-B3 cells.RESULTS:The aberrant expression of COL4A1 was identified a clinically associated with the ARC.Silencing of COL4A1 promoted the apoptosis and inhibited the proliferation of HLE-B3 by blocking the cell cycle.Moreover,COL4A1 gene silence didn’t affect the cytoskeleton of HLE-B3 but down-regulated the Collagen typeⅣAlpha 2 Chain(COL4A2),paired box 6(PAX6),procollagen-lysine 2-oxoglutarate 5-dioxygenases 1(PLOD1)and procollagenlysine 2-oxoglutarate 5-dioxygenases 2(PLOD2)expression levels in HLE-B3 cells.Silencing the COL4A1 gene induced EMT of the HLE-B3 cells by promoting the transforming growth factor beta(TGF-β)expression.CONCLUSION:Silencing of COL4A1 induces S-phase arrest,also inhibits the proliferation and enhance HLE-B3 apoptosis and EMT,and down-regulates the expression of COL4A2,PAX6,PLOD1 and PLOD2.Thus,the expression alteration of COL4A1 may play a critical role in the pathogenesis of ARC.

Extracellular vesicles as a potential therapeutic for age-related macular degeneration

Age-related macular degeneration is a major global cause of central visual impairment and seve re vision loss.With an aging population,the already immense economic burden of costly anti-vascular endothelial growth fa ctor treatment is likely to increase.In addition,current conventional treatment is only available for the late neovascular stage of age-related macular degeneration,and injections can come with potentially devastating complications,introducing the need for more economical and ris kfree treatment.In recent years,exosomes,which are nano-sized extracellular vesicles of an endocytic origin,have shown immense potential as diagnostic biomarkers and in the therapeutic application,as they are bestowed with characte ristics including an expansive cargo that closely resembles their parent cell and exceptional ability of intercellular communication and targeting neighboring cells.Exosomes are currently undergoing clinical trials for various conditions such as type 1 diabetes and autoimmune diseases;however,exosomes as a potential therapy for seve ral retinal diseases have just begun to undergo scrutinizing investigation with little literature on age-related macular degeneration specifically.This article will focus on the limited literature availa ble on exosome transplantation treatment in age-related macular degeneration animal models and in vitro cell cultures,as well as briefly identify future research directions.Current literature on exosome therapy using agerelated macular degeneration rodent models includes laser retinal injury,N-methyl-N-nitrosourea,and royal college of surgeon models,which mimic inflammatory and degenerative aspects of agerelated macular degeneration.These have shown promising results in preserving retinal function and morphology,as well as protecting photoreceptors from apoptosis.Exosomes from their respective cellular origins may also act by regulating the expression of various inflammatory cyto kines,mRNAs,and proteins involved in photo receptor degeneration pathways to exert a therapeutic effect.Various findings have also opened exciting prospects for the involvement of cargo components in remedial effects on the damaged macula or retina.

Development of Knowledge,Attitude and Practice Questionnaire for age-related macular degeneration patients

AIM:To develop and validate a questionnaire to evaluate knowledge,attitude and practice of patients diagnosed with age-related macular degeneration(AMD)who have undergone intravitreal injection treatment.METHODS:This study was conducted among patients diagnosed with AMD in Kuala Lumpur.The generation of the instrument included four phases which included item and domains development,content,face validity and exploratory factor analysis.Content validity and modified Kappa was used for validation of knowledge domain.Exploratory factor analysis was used for validation of both attitude and practice domains.Face validity was conducted in 12 patients,content validity was ascertained in 120 patients and test-retest reliability was determined in 39 patients with AMD.RESULTS:Content validity index(CVI)and modified kappa showed excellent values for most items in the knowledge domain with CVI for item(I-CVI)values between 0.78-1.0 and Kappa values of>0.74.The Kaiser-MeyerOlkin(KMO)sampling adequacy showed acceptable scores of 0.70 and 0.75 for both attitude and practice domains respectively and Bartlett’s Test of sphericity were significant(χ^(2)=0.00,P<0.001).Factor analysis resulted in five factors with thirty items for attitude domain and four factors with twenty items for practice domain.The Cronbach’s alpha showed acceptable values for all items in knowledge,attitude and practice domain with values>0.70 and good test-retest reliability.The final version of the questionnaire consisted of 93 items from four sections consisting of demographic details,knowledge,attitude and practice.CONCLUSION:The findings of this validation and reliability study show that the developed questionnaire has a satisfactory psychometric property for measuring KAP of patients diagnosed with AMD undergoing intravitreal injection treatment.

Circular RNA expression and the competitive endogenous RNA network in pathological,age-related macular degeneration events:A cross-platform normalization study

Age-related macular degeneration(AMD)causes irreversible blindness in people aged over 50 worldwide.The dysfunction of the retinal pigment epithelium is the primary cause of atrophic AMD.In the current study,we used the ComBat and Training Distribution Matching method to integrate data obtained from the Gene Expression Omnibus database.We analyzed the integrated sequencing data by the Gene Set Enrichment Analysis.Peroxisome and tumor necrosis factor-α(TNF-α)signaling and nuclear factor kappa B(NF-κB)were among the top 10 pathways,and thus we selected them to construct AMD cell models to identify differentially expressed circular RNAs(circRNAs).We then constructed a competing endogenous RNA network,which is related to differentially expressed circRNAs.This network included seven circRNAs,15 microRNAs,and 82 mRNAs.The Kyoto Encyclopedia of Genes and Genomes analysis of mRNAs in this network showed that the hypoxia-inducible factor-1(HIF-1)signaling pathway was a common downstream event.The results of the current study may provide insights into the pathological processes of atrophic AMD.

Gene Therapy Activates Retinal Pigment Epithelium Cell Proliferation for Age-related Macular Degeneration in a Mouse Model

Objective Age-related macular degeneration(AMD)is a degenerative retinal disease.The degeneration or death of retinal pigment epithelium(RPE)cells is implicated in the pathogenesis of AMD.This study aimed to activate the proliferation of RPE cells in vivo by using an adeno-associated virus(AAV)vector encodingβ-catenin to treat AMD in a mouse model.Methods Mice were intravitreally injected with AAV2/8-Y733F-VMD2-β-catenin for 2 or 4 weeks,andβ-catenin expression was measured using immunofluorescence staining,real-time quantitative reverse transcription polymerase chain reaction(PCR),and Western blotting.The function ofβ-catenin was determined using retinal flat mounts and laser-induced damage models.Finally,the safety of AAV2/8-Y733F-VMD2-β-catenin was evaluated by multiple intravitreal injections.Results AAV2/8-Y733F-VMD2-β-catenin induced the expression ofβ-catenin in RPE cells.It activated the proliferation of RPE cells and increased cyclin D1 expression.It was beneficial to the recovery of laser-induced damage by activating the proliferation of RPE cells.Furthermore,it could induce apoptosis of RPE cells by increasing the expression of Trp53,Bax and caspase3 while decreasing the expression of Bcl-2.Conclusion AAV2/8-Y733F-VMD2-β-catenin increasedβ-catenin expression in RPE cells,activated RPE cell proliferation,and helped mice heal from laser-induced eye injury.Furthermore,it could induce the apoptosis of RPE cells.Therefore,it may be a safe approach for AMD treatment.

Upregulation of histone H3 caused by CRYAA may contribute to the development of age-related cataract

Objective:Age-relate cataract(ARC)is a disease of the eyes with no effective drugs to prevent or treat patients.The aim of the present study is to determine whether histone H3,αA-crystallin(CRYAA),β-galactosidase(GLB1),and p53 are involved in the pathogenesis of ARC.Methods:A total of 99 anterior lens capsules(ALCs)of patients with ARC of various nuclear grades,ultraviolet models of ALCs,and two human lens epithelial cell lines(FHL-124 and SRA01/04)were used,and the expression of histone H3,CRYAA,GLB1,and p53 were detected by immunoblotting and reverse transcription and real time-quantitative polymerase chain reaction.The association between CRYAA with histone H3,GLB1,and p53 was assessed in FHL-124 and SRA01/04 cells following CRYAA overexpression.Results:Histone H3 and p53 in ALCs of patients with ARC were up-regulated in a grade-dependent manner,and the expression of CRYAA showed a positive association with histone H3,p53,and GLB1.In UV models of ALCs and human lens epithelial cell lines,the expression levels of histone H3,cell apoptosis factors(Bax/Bcl-2,cleaved caspase-3),and inflammation factors(interleukin-6,tumor necrosis factor-α)were all up-regulated.Furthermore,transfection of CRYAA in FHL-124 cells induced overexpression of histone H3.Conclusion:CRYAA-mediated upregulation of histone H3 may be involved in the pathogenesis of ARC.p53 may also have a role in ARC development,but not via the CRYAA-histone H3 axis.The results of the present study may assist in improving our understanding of the pathogenesis of ARC and in identifying potential targets for treatment.

Retinal pigment epithelium–Bruch’s membrane volume in grading of age-related macular degeneration

AIM:To assess the agreement of optical coherence tomography(OCT)algorithm-based retinal pigment epithelium–Bruch’s membrane complex volume(RBV)with fundus photograph-based age-related macular degeneration(AMD)grading.METHODS:Digital color fundus photographs(CFPs)and spectral domain OCT images were acquired from 96 elderly subjects.CFPs were graded according to Age-Related Eye Disease Study(AREDS)classification.OCT image segmentation and RBV data calculation were done with OrionTM software.Univariate and multivariate analyses were performed to find out whether AMD lesion features associated with higher RBVs.RESULTS:RBV correlated with AMD grading(rs=0.338,P=0.001),the correlation was slightly stronger in early AMD(n=52;rs=0.432,P=0.001).RBV was higher in subjects with early AMD compared with those with no AMD lesions evident in fundus photographs(1.05±0.20 vs 0.96±0.13 mm3,P=0.023).In multivariate analysis higher RBVs were associated significantly with higher total drusen(β=0.388,P=0.027)and pigmentation areas(β=0.319,P=0.020)in fundus photographs,whereas depigmentation area(β=-0.295,P=0.015)associated with lower RBV.CONCLUSION:RBV correlate with AMD grading status,with a stronger association in patients with moderate,non-late AMD grades.This effect is driven mostly by lesions with drusen or pigmentation.Lesions with depigmentation tend to have lower values.RBV is more comprehensive measurement of the key area of AMD pathogenesis,compared to sole drusen volume analysis.RBV measurements are independent on grader variations and offer a possibility to quantify early and middle grade AMD lesions in a research setting,but may not substitute fundus photograph-based grading in the whole range of AMD spectrum.

Association between complement factor I gene polymorphisms and the risk of age-related macular degeneration:a Meta-analysis of literature

AIM： To systematically review the association between complement factors I （CFI） polymorphisms and age- related macular degeneration （AMD） and to explore whether CFI polymorphisms are associated with AMD, METHODS： Meta-analysis of articles published from 1995 to January 2015 of articles involved with AMD and polymorphisms of the CFI gene. Eligible data were pooled in a Meta-analysis, analyzing using STATA software （version 12.0）, Review Manager （version 5.2） and different models based on the heterogeneity of effect sizes. Egger＇s test, Begg＇s rank correlation methods were used to evaluate for publication bias.~ RESULTS： Thirteen articles were eligible, describing two loci polymorphisms of the CFI gene （of which 12 articles focus on rs10033900T〉C and 3 articles focus on rs2285714C〉T）. For rs10033900T〉C, the results of our study revealed that having a mutant allele C, TC, CC and TC＋CC was associated with a decreased risk of AMD in all population groups studied （C versus T models, OR=0.84, 95%Ch 0.72-0.99, P=0.04; TC versus TT models OR= 0.89, 95%Ch 0.88-0.99, P=0.04;CC versus ＂1-1＂ models, OR=0.76, 95%Ch 0.60-0.98, P=-0.03; TC＋CC versus TT models, OR=0.81, 95%Ch0.65-0.99, P=0.04）. We found that C allele were related to lower AMD risk in the Caucasian population by subgroup analysis, but there was no association with AMD under the allele and genotypes comparison in Asian studies. For rs2285714 C〉T, the TC, TT genotypes contributed to a higher risk of AMD, compared with the CC carriers and CT＋CC （OR=1.34, 95%Ch 1.09-1.63, P=0.004; OR=1.50, 95%Ch 1.25-1.80, P〈0.0001）. CONCLUSION： This Meta-analysis suggests that CFI rs10033900T〉C and rs2285714C〉T polymorphisms may contribute to AMD.

Progress of clinical therapies for dry age-related macular degeneration

Dry age-related macular degeneration(AMD)is a progressive blinding disease that currently affects millions of people worldwide with no successful treatment available.Significant research efforts are currently underway to develop therapies aimed at slowing the progression of this disease or,more notably,reversing it.Here the therapies which have reached clinical trial for treatment of dry AMD were reviewed.A thorough search of Pub Med,Embase,and Clinicaltrials.gov has led to a comprehensive collection of the most recent strategies being evaluated.This review also endeavors to assess the status and future directions of therapeutics for this debilitating condition.

Age-related maculopathy susceptibility 2 participates in the phagocytosis functions of the retinal pigment epithelium

AIM: Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Many studies suggest that age-related maculopathy susceptibility 2 (ARMS2) is a second major susceptibility gene for AMD. At present, there is no functional information on this gene. Therefore, the purpose of the present study was to detect the expression of ARMS2 in retinal pigment epithelium (RPE) cells and to investigate the effect of ARMS2 on the phagocytosis function of RPE cells. METHODS: Immunofluorescence and reverse transcriptase PCR were used to demonstrate the presence and location of ARMS2 in ARPE-19 (human retinal pigment epithelial cell line, ATCC, catalog No.CRL-2302) cells. siRNA was used to knock down ARMS2 mRNA, and the effects of the knockdown on the phagocytosis function of the ARPE-19 cells were evaluated via Fluorescence Activated Cell Sorting (FACS). RESULTS: ARMS2 was present in ARPE-19 cells, localized in the cytosol of the perinuclear region. The expression of ARMS2 mRNA (messenger RNA) in ARPE-19 cells transfected with ARMS2-siRNA (small interfering RNA, 0.73+/- 0.08) was decreased compared with normal cells (1.00+/- 0.00) or with cells transfected with scrambled siRNA (0.95+/- 0.13) (P<0.05). After incubation of RPE cells with a latex beads medium for 12, 18, or 24 hours, the fluorescence intensities were 38.04 +/- 1.02, 68.92 +/- 0.92, and 78.00 +/- 0.12 in the ARMS2-siRNA-transfected groups, respectively, and 77.98 +/- 5.43, 94.87 +/- 0.60, and 98.30 +/- 0.11 in the scrambled siRNA-transfected groups, respectively. The fluorescent intensities of the same time points in the two groups were compared using Student's t-test, and the p values were all less than 0.001 at the three different time points. CONCLUSION: There is endogenous expression of ARMS2 in ARPE-19 cells. ARMS2 plays a role in the phagocytosis function of RPE cells, and this role may be one of the mechanisms that participates in the development of AMD.

Narrative review of risuteganib for the treatment of dry age-related macular degeneration (AMD)

Age-related macular degeneration(AMD)is a leading cause of blindness worldwide.AMD most commonly affects older individuals and is characterized by irreversible degeneration of the retinal pigment epithelium and neurosensory retina.Currently,there are limited treatment options for dry AMD outside of lifestyle modification and nutrient supplementation.Risuteganib[Luminate(ALG-1001),Allegro Ophthalmics,CA,USA]is an intravitreally administered inhibitor of integrin heterodimersαVβ3,αVβ5,α5β1,andαMβ2.It is currently undergoing clinical trials for the treatment of dry AMD and diabetic macular edema(DME).Preclinical studies have shown that risuteganib has an effect on the pathways for angiogenesis,inflammation,and vascular permeability.Ongoing clinical trials have had promising results showing improvements in patient best corrected visual acuity(BCVA)and reduced central macular thickness measured by optical coherence tomography(OCT).There is a pressing need for treatments for dry AMD and while risuteganib appears to have a potential benefit for patients,more data are needed before one can truly evaluate its efficacy.This narrative review provides a concise summary of the most up to date data regarding the proposed mechanism of action of risuteganib in the treatment of nonexudative AMD and DME as well as the results from recent phase 1 and phase 2 clinical trials.