Resistance to anti-VEGF therapy in neovascular age-related macular degeneration: a comprehensive review

Recent Updates on the Diagnosis and Management of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in the Western world, with a higher prevalence among Europeans and North Americans than that in Africans, Hispanics, and Asians. Advanced AMD is categorized as atrophic (dry) or exudative (wet/neovascular age-related macular degeneration [nAMD]). Dry AMD is characterized by progressive geographic atrophy of the retinal pigment epithelium and outer retinal layers, whereas nAMD is characterized by new vessels that invade the subretinal and/or subretinal pigment epithelium spaces. Existing treatments delay the onset of advanced AMD and reverses vision loss for a couple of years before atrophy usually decreases central visual acuity. We searched PubMed and Medline databases from January 1, 1980, to December 1, 2023, using the following search terms: macular degeneration, choroidal neovascularization, geographic atrophy, drusen, age-related maculopathy, AMD, ARMD, and anti-VEGF. Relevant articles in English (or English translations) were retrieved and reviewed. Bibliographies of the identified manuscripts were also reviewed to identify relevant studies. Age-related macular degeneration most commonly affects people older than 55 years. Visual prognosis varies, with advanced lesions (nAMD and geographic atrophy) leading to rapid, progressive loss of central vision and contrast sensitivity. Although AMD is not a life-threatening disease, reduced vision profoundly compromises quality of life and necessitates living assistance for many patients. Over the past 2 decades, advances in prevention (vitamin supplementation) and therapy (antivascular endothelial growth factor and complement inhibitor drugs) have reduced vision loss and blindness. Further research is needed to decrease the incidence of blindness in patients with advanced disease.

Vascular Endothelial Growth Factor C and D Signaling Pathways as Potential Targets for the Treatment of Neovascular Age-Related Macular Degeneration: A Narrative Review

The development of treatments targeting the vascular endothelial growth factor (VEGF) signaling pathways have traditionally been firstly investigated in oncology and then advanced into retinal disease indications. Members of the VEGF family of endogenous ligands and their respective receptors play a central role in vasculogenesis and angiogenesis during both development and physiological homeostasis. They can also play a pathogenic role in cancer and retinal diseases. Therapeutic approaches have mostly focused on targeting VEGF-A signaling; however, research has shown that VEGF-C and VEGF-D signaling pathways are also important to the disease pathogenesis of tumors and retinal diseases. This review highlights the important therapeutic advances and the remaining unmet need for improved therapies targeting additional mechanisms beyond VEGF-A. Additionally, it provides an overview of alternative VEGF-C and VEGF-D signaling involvement in both health and disease, highlighting their key contributions in the multifactorial pathophysiology of retinal disease including neovascular age-related macular degeneration (nAMD). Strategies for targeting VEGF-C/-D signaling pathways will also be reviewed, with an emphasis on agents currently being developed for the treatment of nAMD.

Publication trends of vascular endothelial growth factor (VEGF) and anti-VEGF treatment in neovascular age-related macular degeneration during 2001-2020: a 20-year bibliometric study

PURPOSE

This study sought to provide an overview of the current research and further analyze publication trends in the field of vascular endothelial growth factor (VEGF) and anti-VEGF treatment for neovascular age-related macular degeneration (NVAMD).

METHODS

We downloaded all related publications from 2001 to 2020 from the Web of Science Core Collection and conducted a bibliometric analysis using the bibiometrix package in R programming software.

RESULTS

A total of 3717 publications were included in the analysis. The USA contributed the largest number of publications (1443), and achieved the highest number of citations (74,946) and H-index value (28). Johns Hopkins University, USA, was the top institution with the most publications, and Peter A. Campochiaro was the most productive professor at The Wilmer Eye Institute, USA. 9.60% of the total publications were from the Journal of Retinal and Vitreous Diseases. Trend analysis demonstrated that anti-VEGF therapy was introduced in early 2000 after steroids, and the last 2 decades have witnessed the blossom of several anti-VEGF agents. "Treat-and-extend" and "resistance" were two popular trend topics in recent years.

CONCLUSIONS

The USA occupies a dominant position in the research field of VEGF and anti-VEGF treatments in NVAMD. Steroid administration, photodynamic therapy, and anti-VEGF therapy have been pivotal advances in the treatment of NVAMD patients over the past 2 decades. Limited acting period and resistance are potential investigation directions in future studies.

Multifunctional nano-in-micro delivery systems for targeted therapy in fundus neovascularization diseases

Fundus neovascularization diseases are a series of blinding eye diseases that seriously impair vision worldwide. Currently, the means of treating these diseases in clinical practice are continuously evolving and have rapidly revolutionized treatment opinions. However, key issues such as inadequate treatment effectiveness, high rates of recurrence, and poor patient compliance still need to be urgently addressed. Multifunctional nanomedicine can specifically respond to both endogenous and exogenous microenvironments, effectively deliver drugs to specific targets and participate in activities such as biological imaging and the detection of small molecules. Nano-in-micro (NIM) delivery systems such as metal, metal oxide and up-conversion nanoparticles (NPs), quantum dots, and carbon materials, have shown certain advantages in overcoming the presence of physiological barriers within the eyeball and are widely used in the treatment of ophthalmic diseases. Few studies, however, have evaluated the efficacy of NIM delivery systems in treating fundus neovascular diseases (FNDs). The present study describes the main clinical treatment strategies and the adverse events associated with the treatment of FNDs with NIM delivery systems and summarizes the anatomical obstacles that must be overcome. In this review, we wish to highlight the principle of intraocular microenvironment normalization, aiming to provide a more rational approach for designing new NIM delivery systems to treat specific FNDs.

Challenges and opportunities of developing small-molecule therapies for age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of vision loss in senior adults. The disease can be categorized into two types: wet AMD and dry AMD. Wet AMD, also known as exudative or neovascular AMD, is less common but more severe than dry AMD and is responsible for 90% of the visual impairment caused by AMD and affects 20 million people worldwide. Current treatment options mainly involve biologics that inhibit the vascular endothelial growth factor or complement pathways. However, these treatments have limitations such as high cost, injection-related risks, and limited efficacy. Therefore, new therapeutic targets and strategies have been explored to improve the outcomes of patients with AMD. A promising approach is the use of small-molecule drugs that modulate different factors involved in AMD pathogenesis, such as tyrosine kinases and integrins. Small-molecule drugs offer advantages, such as oral administration, low cost, good penetration, and increased specificity for the treatment of wet and dry AMD. This review summarizes the current status and prospects of small-molecule drugs for the treatment of wet AMD. These advances are expected to support the development of effective and targeted treatments for patients with AMD.

Role of macrophage in ocular neovascularization

Ocular neovascularization is the leading cause of blindness in clinical settings. Pathological angiogenesis of the eye can be divided into corneal neovascularization (CoNV), retinal neovascularization (RNV, including diabetic retinopathy and retinopathy of prematurity), and choroidal neovascularization (CNV) based on the anatomical location of abnormal neovascularization. Although anti-Vascular endothelial growth factor (VEGF) agents have wide-ranging clinical applications and are an effective treatment for neovascular eye disease, many deficiencies in this treatment strategy remain. Recently, emerging evidence has demonstrated that macrophages are vital during the process of physiological and pathological angiogenesis. Monocyte-macrophage lineage is diverse and plastic, they can shift between different activation modes and have different functions. Due to the obvious regulatory effect of macrophages on inflammation and angiogenesis, macrophages have been increasingly studied in the field of ophthalmology. Here, we detail how macrophage activated and the role of different subtypes of macrophages in the pathogenesis of ocular neovascularization. The complexity of macrophages has recently taken center stage owing to their subset diversity and tightly regulated molecular and metabolic phenotypes. In this review, we reveal the functional and phenotypic characterization of macrophage subsets associated with ocular neovascularization, more in-depth research is needed to explore the specific mechanisms by which macrophages regulate angiogenesis as well as macrophage polarization. Targeted regulation of macrophage differentiation based on their phenotype and function could be an effective approach to treat and manage ocular neovascularization in the future.

Double-dose investigation of aflibercept in neovascular age-related macular degeneration (DIANA): a real-world study

BACKGROUND

To investigate the clinical effects of double-dose (4 mg) aflibercept treatment in neovascular age-related macular degeneration (nAMD), compared with the standard-dose (2 mg) treatment.

METHODS

A total of 108 eyes from 97 patients with nAMD and received intravitreal aflibercept 2 mg and/or 4 mg treatment were retrospectively reviewed. The changes of central macular thickness (CMT)/ pigmental epithelium detachment height and the recurrence rate of exudation during the 12-month follow-up were compared between the 2 mg group and the 4 mg group. Self-control comparisons (2 mg switch to 4 mg) were also made between two regimens.

RESULTS

Compared with the 2 mg group, tendencies of lower intraretinal fluid incidence and more CMT reduction were observed in the 4 mg group. The later one was also observed when eyes switching from 2 mg to 4 mg regimen. The median remission interval was 5 months in the 4 mg group, 2 months longer than the 3 months in the 2 mg group (P = 0.452). Injections needed in the 4 mg group were 3.644 ± 1.670, less than the 4.286 ± 2.334 injections in the 2 mg group within 12 months as well (P = 0.151). However, no associated vision benefits were gained from the double-douse regimen. No markedly increased-intraocular pressure events, or other adverse events were found in two groups.

CONCLUSIONS

Compared to the aflibercept 2 mg treatment in nAMD, tendencies of anatomic gains and relieving treatment burden were brought by the aflibercept 4 mg treatment. This study may have additional importance, given the further application of high-dose aflibercept in real-world settings.

2-Desaza-annomontine (C81) impedes angiogenesis through reduced VEGFR2 expression derived from inhibition of CDC2-like kinases

Angiogenesis is a crucial process in the progression of various pathologies, like solid tumors, wet age-related macular degeneration, and chronic inflammation. Current anti-angiogenic treatments still have major drawbacks like limited efficacy in diseases that also rely on inflammation. Therefore, new anti-angiogenic approaches are sorely needed, and simultaneous inhibition of angiogenesis and inflammation is desirable. Here, we show that 2-desaza-annomontine (C81), a derivative of the plant alkaloid annomontine previously shown to inhibit endothelial inflammation, impedes angiogenesis by inhibiting CDC2-like kinases (CLKs) and WNT/β-catenin signaling. C81 reduced choroidal neovascularization in a laser-induced murine in vivo model, inhibited sprouting from vascular endothelial growth factor A (VEGF-A)-activated murine aortic rings ex vivo, and reduced angiogenesis-related activities of endothelial cells in multiple functional assays. This was largely phenocopied by CLK inhibitors and knockdowns, but not by inhibitors of the other known targets of C81. Mechanistically, CLK inhibition reduced VEGF receptor 2 (VEGFR2) mRNA and protein expression as well as downstream signaling. This was partly caused by a reduction of WNT/β-catenin pathway activity, as activating the pathway induced, while β-catenin knockdown impeded VEGFR2 expression. Surprisingly, alternative splicing of VEGFR2 was not detected. In summary, C81 and other CLK inhibitors could be promising compounds in the treatment of diseases that depend on angiogenesis and inflammation due to their impairment of both processes.

Short-term response to anti-VEGF as indicator of visual prognosis in refractory age-related macular degeneration

BACKGROUND

Some patients with neovascular age-related macular degeneration (nAMD) respond insufficiently to anti-VEGF treatment despite maximal monthly intravitreal injections. Their short-term response between injections was investigated for extent and visual prognosis.

SUBJECTS/METHODS

Monocentric retrospective observational study. 45 eyes from 41 patients with refractory nAMD (who previously received at least 12 months of anti-VEGF treatment), evaluated by optical coherence tomography (OCT) in between monthly anti-VEGF injections. The fluid profile on OCT was evaluated before, 1 week after, and 1 month after an intravitreal injection, using central retinal thickness (CRT), manual measurements, and fluid specific volumetric measurements performed by an automated algorithm based on artificial intelligence.

RESULTS

A significant improvement was found at week 1 in terms of CRT (p < 0.0001), intraretinal (IRF) (p = 0.007), subretinal fluid (SRF) (p < 0.0001), and pigment epithelium detachment (PED) volume (p < 0.0001). Volumetric fluid measures revealed a >50% reduction at week 1 for both IRF and SRF for approximately two-thirds of eyes. Poorer short-term response was associated with larger exudative fluid amounts (IRF + SRF) (p = 0.003), larger PED (p = 0.007), lower visual acuity (p = 0.004) and less anatomic changes at treatment initiation (p < 0.0001). Univariate and multivariate analysis revealed that visual outcomes 4 and 5 years later was significantly worse with weaker short-term responsiveness (p = 0.005), with the presence of atrophy (p = 0.01) and larger PED volumes (p = 0.002).

CONCLUSIONS

Incomplete responders to anti-VEGF showed a significant short-term response, identifiable at 1 week after injection, with rapid recurrence at 1 month. Weaker short-term responsiveness at 1 week was associated with poorer long term visual prognosis. These patients may need adjuvant treatment to improve their prognosis.

Oxidative Stress Participates in Age-Related Cataract Formation by Disrupting Connection between Lens Epithelial Cells through c-Src/VEGF Pathway

PURPOSE

To observe the effects of oxidative stress on vascular endothelial growth factor (VEGF) and connections of lens epithelial cells.

METHODS

Human lens epithelium of patients with age-related cataract (ARC), both SRA01/04 cells and whole mice lens stimulated by H2O2 were employed. VEGF in human aqueous humor of ARC-patients and the supernatant of SRA01/04 cells was determined by ELISA. The expressions of VEFG in human lens epithelium were detected by immunofluorescence staining. Multiple linear regression analysis and spearman rank-order correlation were used to determine the associations between VEGF and parameters of ARC individuals. In H2O2-induced SRA01/04 cells, Catalase (CAT), PP1 (inhibitor of c-Src kinase) and Avastin (VEGF antibody) were used to inhibit the effects of H2O2, activation of c-Src kinase and VEGF, which were detected by Western blot. The alterations of ZO-1 and N-cadherin were tested by immunofluorescence staining and Western blot. In H2O2-induced whole lens, the changes of opacification area in different treatment of inhibitors were observed.

RESULTS

The secretion of VEGF in aqueous humor and expression of VEGF in the lens epithelium of ARC patients increased significantly with age. In H2O2-induced SRA01/04 cells, the VEGF in the supernatant was increased with the culture duration and the dose of H2O2. The expressions of p-Src418 and VEGF were also up-regulated, whereas the expressions of ZO-1 and N-cadherin were down-regulated. CAT effectively prevented these changes induced by H2O2, while PP1 inhibited not only p-Src418 but also up-regulation of VEGF, Avastin partially inhibited VEGF up-regulation. Both PP1 and Avastin prevented down-regulation of ZO-1 and N-cadherin, respectively, but Avastin combined with PP1 had no significant synergistic effects. In H2O2-induced cataract, CAT prevented development of opacification area effectively, and PP1 and Avastin did partially.

CONCLUSIONS

Oxidative stress disrupts connections of lens epithelial cells by activating c-Src/VEGF, inhibiting which may prevent cataract.

Granzyme B degrades extracellular matrix and promotes inflammation and choroidal neovascularization

Age-related macular degeneration (AMD) is a common retinal neurodegenerative disease among the elderly. Neovascular AMD (nAMD), a leading cause of AMD-related blindness, involves choroidal neovascularization (CNV), which can be suppressed by anti-angiogenic treatments. However, current CNV treatments do not work in all nAMD patients. Here we investigate a novel target for AMD. Granzyme B (GzmB) is a serine protease that promotes aging, chronic inflammation and vascular permeability through the degradation of the extracellular matrix (ECM) and tight junctions. Extracellular GzmB is increased in retina pigment epithelium (RPE) and mast cells in the choroid of the healthy aging outer retina. It is further increased in donor eyes exhibiting features of nAMD and CNV. Here, we show in RPE-choroidal explant cultures that exogenous GzmB degrades the RPE-choroid ECM, promotes retinal/choroidal inflammation and angiogenesis while diminishing anti-angiogenic factor, thrombospondin-1 (TSP-1). The pharmacological inhibition of either GzmB or mast-cell degranulation significantly reduces choroidal angiogenesis. In line with our in vitro data, GzmB-deficiency reduces the extent of laser-induced CNV lesions and the age-related deterioration of electroretinogram (ERG) responses in mice. These findings suggest that targeting GzmB, a serine protease with no known endogenous inhibitors, may be a potential novel therapeutic approach to suppress CNV in nAMD.

Treatment Strategies for Anti-VEGF Resistance in Neovascular Age-Related Macular Degeneration by Targeting Arteriolar Choroidal Neovascularization

Despite extensive use of intravitreal anti-vascular endothelial growth factor (anti-VEGF) biologics for over a decade, neovascular age-related macular degeneration (nAMD) or choroidal neovascularization (CNV) continues to be a major cause of irreversible vision loss in developed countries. Many nAMD patients demonstrate persistent disease activity or experience declining responses over time despite anti-VEGF treatment. The underlying mechanisms of anti-VEGF resistance are poorly understood, and no effective treatment strategies are available to date. Here we review evidence from animal models and clinical studies that supports the roles of neovascular remodeling and arteriolar CNV formation in anti-VEGF resistance. Cholesterol dysregulation, inflammation, and ensuing macrophage activation are critically involved in arteriolar CNV formation and anti-VEGF resistance. Combination therapy by neutralizing VEGF and enhancing cholesterol removal from macrophages is a promising strategy to combat anti-VEGF resistance in CNV.

Liquid Biopsy Proteomics in Ophthalmology

Minimally invasive liquid biopsies from the eye capture locally enriched fluids that contain thousands of proteins from highly specialized ocular cell types, presenting a promising alternative to solid tissue biopsies. The advantages of liquid biopsies include sampling the eye without causing irreversible functional damage, potentially better reflecting tissue heterogeneity, collecting samples in an outpatient setting, monitoring therapeutic response with sequential sampling, and even allowing examination of disease mechanisms at the cell level in living humans, an approach that we refer to as TEMPO (Tracing Expression of Multiple Protein Origins). Liquid biopsy proteomics has the potential to transform molecular diagnostics and prognostics and to assess disease mechanisms and personalized therapeutic strategies in individual patients. This review addresses opportunities, challenges, and future directions of high-resolution liquid biopsy proteomics in ophthalmology, with particular emphasis on the large-scale collection of high-quality samples, cutting edge proteomics technology, and artificial intelligence-supported data analysis.

Calpain-specific breakdown fragment in human drusen

PURPOSE

With aging and age-related macular dystrophy (AMD), proteolytic fragments are deposited in extracellular drusen located between the RPE and Bruch's membrane. Localized hypoxia may be a risk factor for AMD. Our hypothesis is that following hypoxia, activation of proteolytic enzymes called calpains may cause proteolysis/degeneration of retinal cells and RPE. No direct evidence has yet demonstrated activation of calpains in AMD. The purpose of the present study was to identify calpain-cleaved proteins in drusen.

METHODS

Seventy-six (76) drusen were analyzed in human eye sections from six normal and twelve AMD human donor eyes. The sections were subjected to immunofluorescence for the calpain-specific 150 kDa breakdown product from α-spectrin, SBDP150 - a marker for calpain activation, and for recoverin - a marker for photoreceptor cells.

RESULTS

Among 29 nodular drusen, 80% from normal eyes and 90% from AMD eyes stained positive for SBDP150. Among 47 soft drusen, mostly from AMD eyes, 72% stained positive for SBDP150. Thus, the majority of both soft and nodular drusen from AMD donors contained SBDP150.

CONCLUSIONS

SBDP150 was detected for the first time in soft and nodular drusen from human donors. Our results suggest that calpain-induced proteolysis participates in the degeneration of photoreceptors and/or RPE cells during aging and AMD. Calpain inhibitors may ameliorate AMD progression.

Long-term choroidal thickness changes based on the subtype of macular neovascularization in neovascular age-related macular degeneration (5-year follow-up)

PURPOSE

To evaluate the long-term choroidal thickness changes in combination with other morphological and functional outcomes during anti-vascular endothelial growth factor (VEGF) treatment for neovascular age-related macular degeneration (nAMD) based on the subtype of macular neovascularization (MNV): MNV-1 (within the subretinal pigment epithelium space) and MNV-2 (within the subretinal space).

METHODS

This retrospective study included 58 eyes from 53 patients with naïve nAMD who received anti-VEGF therapy over a 60-month period. All eyes were treated initially with intravitreal bevacizumab following Pro re nata regimen. Main outcome measures included the following: subfoveal choroidal thickness (SFCT), best corrected visual acuity (BCVA), central macular thickness (CMT), development of subfoveal geographic atrophy (GA), and the number of injections.

RESULTS

Thirty-four eyes had MNV-1 (group 1) and 24 eyes had MNV-2 (group 2). SFCT in group 1 vs group 2 was (210 ± 45 µm vs 191 ± 52 µm, p = 0.01) before treatment and (170 ± 47 µm vs 179 ± 48 µm, p = 0.24) after 60 months. BCVA (log MAR) in group 1 vs group 2 was (0.57 ± 0.18 vs 0.53 ± 0.22, p = 0.47) before treatment and (0.59 ± 0.23 vs 0.69 ± 0.16, p = 0.04) after 60 months. CMT in group 1 vs group 2 was (398 ± 154 µm vs 382 ± 103 µm, p = 0.86) before treatment and (297 ± 68 µm vs 283 ± 67 µm, p = 0.14) after 60 months. The number of injections per eye over a period of 60 months was significantly higher in group 1 (34.9 ± 11 vs 29.0 ± 14, p = 0.04). The proportion of eyes with subfoveal GA after 60 months was significantly higher in group 2 (13 eyes, 54%) than in group 1 (9 eyes, 25%) (p = 0.03).

CONCLUSION

Over the full 60 months of anti-VEGF treatment, eyes with MNV-1 showed a greater reduction in choroidal thickness, better visual acuity, and less development of subfoveal geographic atrophy compared with eyes with MNV-2. The significantly thicker choroid in eyes with MNV type 1 at baseline seems to have a positive impact on long-term outcomes.

Bioinformatics and Network Pharmacology Explore the Role of Immune Cells in the Occurrence of Anti-Vascular Endothelial Growth Factor (VEGF) Resistance in Patients with Neovascular Age-Related Macular Degeneration(nAMD) and the Application of Complementary Medicine Treatment

PURPOSE

This study explores the immune cells' role in anti-VEGF resistance in nAMD patients, and the potential of Zi-Yin-Jiang-Huo-Tang (ZYJHT), a Traditional Chinese Medicine formula, as complementary therapy.

METHODS

Aqueous humor proteomics data from 10 nAMD patients with anti-VEGF resistance and 10 nAMD patients without anti-VEGF resistance were analyzed, investigating immune cells's role in anti-VEGF resistance and its underlying mechanism. Network pharmacology methods are employed to analyze the active ingredients in ZYJHT that contribute to therapeutic effects and their mechanisms. Real-time PCR (polymerase chain reaction) was used to detect changes in the expression of SOD1 (superoxide dismutase 1) after treatment with compounds targeting SOD1 in ARPE-19 cells.

RESULTS

nAMD patients with anti-VEGF resistance showed enhancement of biological processes linked to the positive regulation of immune function, along with decreased cellular resistance to oxidative stress. Infiltration of B cells memory, plasma cells, CD8+and γδ-T cells were higher in nAMD patients with anti-VEGF resistance. SOD1 was identified as a hub gene in the occurrence of anti-VEGF resistance and a core therapeutic target of ZYJHT, negatively correlated with B and T cell infiltration. Compounds diosgenin, naringenin, and liquiritin in ZYJHT can bind to SOD1 and upregulating SOD1 expression in ARPE-19 cells.

Age-Related Macular Degeneration - Therapies and Their Delivery

Age-related macular degeneration (ARMD) is a degenerative ocular disease that is the most important cause of irreversible vision loss in old-aged people in developed countries. Around fifty percent of vision impairments in developed countries are due to ARMD. It is a multifaceted disease that is associated with both genetic and environmental risk factors. The most important treatments option for ARMD includes laser photocoagulation, photodynamic therapy (PDT), Anti-VEGF Injections, and combination therapies. In this review, we also propose that topical ocular drug delivery with nanocarriers has more attention for the treatment of ARMD. The nanocarriers were specially designed for enhanced corneal residential time, prolonged drug release and action, and minimizing the frequency of administrations. Different types of nanocarriers were developed for the topical ocular delivery system, such as nanomicelles, nanoemulsions, nanosuspensions, liposomes, and polymeric nanoparticles. These topical ocular nanocarriers were administered topically, and they can fix the hydrophobic substances, increase solubility and improve the bioavailability of an administered drug. Hence the topical ocular delivery systems with nanocarriers provide a safe and effective therapeutic strategy and promising tool for the treatment of posterior segment ocular diseases ARMD.

Diabetic Macular Edema Management: A Review of Anti-Vascular Endothelial Growth Factor (VEGF) Therapies

Diabetic macular edema (DME) is a major cause of vision impairment in diabetic individuals, characterized by fluid accumulation in the macula due to a breakdown of the blood-retinal barrier (BRB). This review article explores the role of anti-vascular endothelial growth factor (anti-VEGF) therapies in the management of DME. Anti-VEGF treatments, including ranibizumab, bevacizumab, and aflibercept, have revolutionized DME management by targeting VEGF, a key mediator in DME pathogenesis. We critically examined the efficacy of these therapies in reducing macular edema and improving visual acuity, assessed their safety and tolerability, and explored the variability in treatment response. The review highlights the latest advancements and future directions in anti-VEGF therapy, including novel drug delivery systems and emerging treatment paradigms. By providing a comprehensive overview of current anti-VEGF therapies, this review seeks to inform clinical practice, guide future research, and contribute to improved patient outcomes in DME management.

Six-month outcomes of switching from aflibercept to faricimab in refractory cases of neovascular age-related macular degeneration

PURPOSE

To assess 6-month outcomes of switching from aflibercept to faricimab in eyes with refractory neovascular age-related macular degeneration (nAMD) previously requiring monthly injections.

METHODS

This multicenter retrospective study examined nAMD eyes receiving monthly aflibercept injections switched to faricimab administered monthly up to 4 injections followed by injections at a minimum of 2-month intervals as per drug labeling. Data regarding age, sex, number of previous injections, treatment intervals, and best-corrected visual acuity (BCVA) were collected. Central retinal thickness (CRT), subfoveal choroidal thickness (SFCT), and maximal pigment epithelial detachment (PED) height were measured by optical coherence tomography.

RESULTS

The study included 130 eyes of 124 patients. At 6 months, 53 eyes (40.8%) continued on faricimab treatment (Group 1), while 77 eyes (59.2%) discontinued faricimab for various reasons (Group 2) the most common being worse exudation. There were no significant differences between the two groups at baseline. In Group 1, CRT and SFCT significantly decreased at 1 month (P = 0.013 and 0.008), although statistical significance was lost at 6 months (P = 0.689 and 0.052). BCVA and maximal PED height showed no significant changes; however, mean treatment intervals were extended from 4.4 ± 0.5 weeks at baseline to 8.7 ± 1.7 weeks at 6 months (P < 0.001) in Group 1. No clear predictors of response were identified.

CONCLUSION

Switching from aflibercept to faricimab allowed for extension of treatment intervals from monthly to bimonthly in roughly 40% of eyes, suggesting that faricimab may be considered in refractory nAMD cases.

Diagnosing Polypoidal Choroidal Vasculopathy Using Color Fundus Photography, Optical Coherence Tomography, and Optical Coherence Tomography Angiography

PURPOSE

To compare the diagnostic accuracy of differentiating polypoidal choroidal vasculopathy (PCV) from exudative age-related macular degeneration (AMD), using color fundus photography (CFP), optical coherence tomography (OCT), and swept-source OCT angiography (SS-OCTA) without using indocyanine green angiography (ICGA).

METHODS

Treatment-naive eyes with exudative AMD that underwent CFP, OCT, SS-OCTA, and ICGA imaging before treatment were identified. Images of each patient were categorized into two sets (set A, CFP + OCT; set B, CFP + SS-OCTA). In set B, both the en face and cross-sectional B scans were analyzed. Each set was reviewed by two graders, and it was determined whether the presumed diagnosis was PCV. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for the diagnosis of PCV were assessed for each set by comparing diagnoses that included ICGA. The number of polypoidal lesions in each set was calculated and compared to ICGA.

RESULTS

A total of 94 eyes from 94 patients with AMD were included in the study, of which 66.0% were male, and the mean age was 71.8 ± 9.0 years. The PCV diagnosis rate using ICGA was 45.7%. The sensitivity was 0.88 for set A and 0.93 for set B, while the specificity was 0.94 for set A and 0.96 for set B. The AUC was 0.90 (95% confidence interval [CI], 0.83-0.97) for set A and 0.96 (95% CI, 0.90-1.00) for set B. Set A detected 1.28 ± 0.91 polypoidal lesions, while set B detected 1.47 ± 1.01; ICGA showed 1.51 ± 0.86.

CONCLUSIONS

This study highlights that, without using ICGA, both CFP combined with OCT and CFP combined with SS-OCTA demonstrate high sensitivity, specificity, and AUC in diagnosing PCV. It is evident that SS-OCTA contributes to enhancing sensitivity, specificity, and AUC for PCV diagnosis.

One-Year and 18-Month Outcomes in nAMD Patient Eyes Switched to Brolucizumab Alone versus to Brolucizumab Alternating with Other Anti-VEGF Agents

Objective

Retrospective, real-world study to evaluate visual acuity (VA), anti-vascular endothelial growth factor (anti-VEGF) injection intervals, and central macular thickness (CMT) in neovascular age-related macular degeneration (nAMD) eyes switched to brolucizumab only or to brolucizumab alternating with another anti-VEGF.

Methods

The overall study population comprised eyes that were given ≥1 brolucizumab injection between 1 October 2019 and 30 November 2021. The brolucizumab-only (BRO) cohort consisted of prior anti-VEGF-treated eyes treated exclusively with ≥3 brolucizumab injections over ≥12 or ≥18 months; the alternating brolucizumab (ALT) cohort comprised prior anti-VEGF-treated eyes treated with ≥2 brolucizumab injections and ≥1 other anti-VEGF over ≥12 or ≥18 months.

Results

A total of 482 eyes received ≥1 brolucizumab injection during the study period. Mean VA changes from baseline were -1.1±15.1 letters (BRO cohort; n = 174) and 1.3±13.0 letters (ALT cohort; n = 47) at Month 12, and 0.0±13.5 letters (BRO cohort; n = 95) and -7.3±17.2 letters (ALT cohort; n = 29) at Month 18. Mean changes in injection intervals were +26.9±48.1 days (BRO cohort) and +11.1±17.3 days (ALT cohort) at Month 12 and +36.3±52.3 days (BRO cohort) and +14.0±19.9 days (ALT cohort) at Month 18. Mean changes in CMT were -35.2±108.1 μm (BRO cohort) and -31.5±91.2 μm (ALT cohort) at Month 12 and -38.9±75.0 μm (BRO cohort) and -9.0±59.9 μm (ALT cohort) at Month 18. Intraocular inflammation-related adverse events were recorded in 22/482 (4.6%) eyes.

Conclusion

Treatment with either brolucizumab alone or brolucizumab alternating with another anti-VEGF can preserve vision, reduce CMT, and extend anti-VEGF injection intervals in patients with nAMD.

Targeting FSCN1 with an oral small-molecule inhibitor for treating ocular neovascularization

BACKGROUND

Ocular neovascularization is a leading cause of blindness and visual impairment. While intravitreal anti-VEGF agents can be effective, they do have several drawbacks, such as endophthalmitis and drug resistance. Additional studies are necessary to explore alternative therapeutic targets.

METHODS

Bioinformatics analysis and quantitative RT-PCR were used to detect and verify the FSCN1 expression levels in oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) mice model. Transwell, wound scratching, tube formation, three-dimensional bead sprouting assay, rhodamine-phalloidin staining, Isolectin B4 staining and immunofluorescent staining were conducted to detect the role of FSCN1 and its oral inhibitor NP-G2-044 in vivo and vitro. HPLC-MS/MS analysis, cell apoptosis assay, MTT assay, H&E and tunnel staining, visual electrophysiology testing, visual cliff test and light/dark transition test were conducted to assess the pharmacokinetic and security of NP-G2-044 in vivo and vitro. Co-Immunoprecipitation, qRT-PCR and western blot were conducted to reveal the mechanism of FSCN1 and NP-G2-044 mediated pathological ocular neovascularization.

RESULTS

We discovered that Fascin homologue 1 (FSCN1) is vital for angiogenesis both in vitro and in vivo, and that it is highly expressed in oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV). We found that NP-G2-044, a small-molecule inhibitor of FSCN1 with oral activity, can impede the sprouting, migration, and filopodia formation of cultured endothelial cells. Oral NP-G2-044 can effectively and safely curb the development of OIR and CNV, and increase efficacy while overcoming anti-VEGF resistance in combination with intravitreal aflibercept (Eylea) injection.

CONCLUSION

Collectively, FSCN1 inhibition could serve as a promising therapeutic approach to block ocular neovascularization.

Exploring the Relationship between Anti-VEGF Therapy and Glaucoma: Implications for Management Strategies

A short-term increase in intraocular pressure (IOP) is a common side effect after intravitreal anti-VEGF therapy, but a sustained increase in IOP with the development of secondary glaucoma has also been reported in some studies after repeated intravitreal anti-VEGF injections. The aim of this review is to present and discuss the possible pathophysiological mechanisms and factors contributing to a sustained rise in IOP, as well as treatment strategies for patients at risk. Close monitoring and adjustable IOP-lowering treatment are recommended for high-risk patients, including those with glaucoma, angle-closure anomalies, ocular hypertension or family history of glaucoma; patients receiving a high number of injections or at shorter intervals; and patients with capsulotomy. Strategies are needed to identify patients at risk in a timely manner and to prevent sustained elevation of IOP.

Beyond VEGF: Targeting Inflammation and Other Pathways for Treatment of Retinal Disease

Neovascular eye diseases include conditions such as retinopathy of prematurity, proliferative diabetic retinopathy, and neovascular age-related macular degeneration. Together, they are a major cause of vision loss and blindness worldwide. The current therapeutic mainstay for these diseases is intravitreal injections of biologics targeting vascular endothelial growth factor (VEGF) signaling. Lack of universal response to these anti-VEGF agents coupled with the challenging delivery method underscore a need for new therapeutic targets and agents. In particular, proteins that mediate both inflammatory and proangiogenic signaling are appealing targets for new therapeutic development. Here, we review agents currently in clinical trials and highlight some promising targets in preclinical and early clinical development, focusing on the redox-regulatory transcriptional activator APE1/Ref-1, the bioactive lipid modulator soluble epoxide hydrolase, the transcription factor RUNX1, and others. Small molecules targeting each of these proteins show promise for blocking neovascularization and inflammation. The affected signaling pathways illustrate the potential of new antiangiogenic strategies for posterior ocular disease. SIGNIFICANCE STATEMENT: Discovery and therapeutic targeting of new angiogenesis mediators is necessary to improve treatment of blinding eye diseases like retinopathy of prematurity, diabetic retinopathy, and neovascular age-related macular degeneration. Novel targets undergoing evaluation and drug discovery work include proteins important for both angiogenesis and inflammation signaling, including APE1/Ref-1, soluble epoxide hydrolase, RUNX1, and others.

Recent advances of exosomes in age-related macular degeneration

Exosomes are 30-150 nm extracellular vesicles that are secreted by almost all types of cells. Exosomes contain a variety of biologically active substances, such as proteins, nucleic acids, and lipids, and are important in the intercellular communication of biological mediators involved in nerve injury and repair, vascular regeneration, immune response, fibrosis formation, and many other pathophysiological processes. Although it has been extensively studied in the field of cancer, the exploration of ocular diseases has only just begun. Here, we discuss the latest developments in exosomes for age-related macular degeneration (AMD), including the pathogenesis of exosomes in age-related macular degeneration, their potential as diagnostic markers, and therapeutic vectors of the disease. Finally, the study of exosomes in age-related macular degeneration is still relatively few, and more detailed basic research and clinical trials are needed to verify its application in treatment and diagnosis, so as to adopt more personalized diagnosis and treatment strategies to stop the progression of age-related macular degeneration.

Proteomics Analysis of R-Ras Deficiency in Oxygen Induced Retinopathy

Small GTPase R-Ras regulates vascular permeability in angiogenesis. In the eye, abnormal angiogenesis and hyperpermeability are the leading causes of vision loss in several ischemic retinal diseases such as proliferative diabetic retinopathy (PDR), retinal vein occlusion (RVO), and retinopathy of prematurity (ROP). Oxygen-induced retinopathy (OIR) is the most widely used experimental model for these ischemic retinopathies. To shed more light on how the R-Ras regulates vascular permeability in pathological angiogenesis, we performed a comprehensive (>2900 proteins) characterization of OIR in R-Ras knockout (KO) and wild-type (WT) mice by sequential window acquisition of all theoretical mass spectra (SWATH-MS) proteomics. OIR and age-matched normoxic control retinas were collected at P13, P17, and P42 from R-Ras KO and WT mice and were subjected to SWATH-MS and data analysis. The most significant difference between the R-Ras KO and WT retinas was an accumulation of plasma proteins. The pathological vascular hyperpermeability during OIR in the R-Ras KO retina took place very early, P13. This led to simultaneous hypoxic cell injury/death (ferroptosis), glycolytic metabolism as well compensatory mechanisms to counter the pathological leakage from angiogenic blood vessels in the OIR retina of R-Ras deficient mice.

YY1 lactylation in microglia promotes angiogenesis through transcription activation-mediated upregulation of FGF2

BACKGROUND

Ocular neovascularization is a leading cause of blindness. Retinal microglia have been implicated in hypoxia-induced angiogenesis and vasculopathy, but the underlying mechanisms are not entirely clear. Lactylation is a novel lactate-derived posttranslational modification that plays key roles in multiple cellular processes. Since hypoxia in ischemic retinopathy is a precipitating factor for retinal neovascularization, lactylation is very likely to be involved in this process. The present study aimed to explore the role of lactylation in retinal neovascularization and identify new therapeutic targets for retinal neovascular diseases.

RESULTS

Microglial depletion by the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX3397 suppresses retinal neovascularization in oxygen-induced retinopathy. Hypoxia increased lactylation in microglia and accelerates FGF2 expression, promoting retinal neovascularization. We identify 77 sites of 67 proteins with increased lactylation in the context of increased lactate under hypoxia. Our results show that the nonhistone protein Yin Yang-1 (YY1), a transcription factor, is lactylated at lysine 183 (K183), which is regulated by p300. Hyperlactylated YY1 directly enhances FGF2 transcription and promotes angiogenesis. YY1 mutation at K183 eliminates these effects. Overexpression of p300 increases YY1 lactylation and enhances angiogenesis in vitro and administration of the p300 inhibitor A485 greatly suppresses vascularization in vivo and in vitro.

CONCLUSIONS

Our results suggest that YY1 lactylation in microglia plays an important role in retinal neovascularization by upregulating FGF2 expression. Targeting the lactate/p300/YY1 lactylation/FGF2 axis may provide new therapeutic targets for proliferative retinopathies.

The cGAS-STING pathway in diabetic retinopathy and age-related macular degeneration

Diabetic retinopathy and age-related macular degeneration are common retinal diseases with shared pathophysiology, including oxidative stress-induced inflammation. Cellular mechanisms responsible for converting oxidative stress into retinal damage are ill-defined but have begun to clarify. One common outcome of retinal oxidative stress is mitochondrial damage and subsequent release of mitochondrial DNA into the cytosol. This leads to activation of the cGAS-STING pathway, resulting in interferon release and disease-amplifying inflammation. This review summarizes the evolving link between aberrant cGAS-STING signaling and inflammation in common retinal diseases and provides prospective for targeting this system in diabetic retinopathy and age-related macular degeneration. Further defining the roles of this system in the retina is expected to reveal new disease pathology and novel therapeutic approaches.

JP1, a polypeptide specifically targeting integrin αVβ3, ameliorates choroidal neovascularization and diabetic retinopathy in mice

Anti-vascular endothelial growth factor (VEGF) drugs have revolutionized the treatment of neovascular eye diseases, but responses are incomplete in some patients. Recent evidence shows that integrins are involved in the pathogenesis of neovascular age-related macular degeneration and diabetic retinopathy. JP1, derived from an optimized seven-amino-acid fragment of JWA protein, is a polypeptide specifically targeting integrin αVβ3. In this study we evaluated the efficacy of JP1 on laser-induced choroidal neovascularization (CNV) and retinal vascular leakage. CNV mice received a single intravitreal (IVT) injection of JP1 (10, 20, 40 µg) or ranibizumab (RBZ, 10 µg). We showed that JP1 injection dose-dependently inhibited laser-induced CNV; the effect of RBZ was comparable to that of 20 µg JP1; a combined IVT injection of JP1 (20 μg) and RBZ (5 μg) exerted a synergistic effect on CNV. In the 3rd month after streptozotocin injection, diabetic mice receiving IVT injection of JP1 (40 µg) or RBZ (10 µg) once a week for 4 weeks showed significantly suppressed retinal vascular leakage. In both in vivo and in vitro experiments, JP1 counteracted oxidative stress and inflammation via inhibiting ROS/NF-κB signaling in microglial cells, and angiogenesis via modulating MEK1/2-SP1-integrin αVβ3 and TRIM25-SP1-MMP2 axes in vascular endothelial cells. In addition, intraperitoneal injection of JP1 (1, 5 or 10 mg) once every other day for 3 times also dose-dependently inhibited CNV. After intraperitoneal injection of FITC-labeled JP1 (FITC-JP1) or FITC in laser-induced CNV mice, the fluorescence intensity in the CNV lesion was markedly increased in FITC-JP1 group, compared with that in FITC group, confirming that JP1 could penetrate the blood-retinal barrier to target CNV lesion. We conclude that JP1 can be used to design novel CNV-targeting therapeutic agents that may replace current invasive intraocular injections.

Advances in the mechanisms and applications of inhibitory oligodeoxynucleotides against immune-mediated inflammatory diseases

Inhibitory oligodeoxynucleotides (ODNs) are short single-stranded DNA, which capable of folding into complex structures, enabling them to bind to a large variety of targets. With appropriate modifications, the inhibitory oligodeoxynucleotides exhibited many features of long half-life time, simple production, low toxicity and immunogenicity. In recent years, inhibitory oligodeoxynucleotides have received considerable attention for their potential therapeutic applications in immune-mediated inflammatory diseases (IMIDs). Inhibitory oligodeoxynucleotides could be divided into three categories according to its mechanisms and targets, including antisense ODNs (AS-ODNs), DNA aptamers and immunosuppressive ODNs (iSup ODNs). As a synthetic tool with immunomodulatory activity, it can target RNAs or proteins in a specific way, resulting in the reduction, increase or recovery of protein expression, and then regulate the state of immune activation. More importantly, inhibitory oligodeoxynucleotides have been used to treat immune-mediated inflammatory diseases, including inflammatory disorders and autoimmune diseases. Several inhibitory oligodeoxynucleotide drugs have been developed and approved on the market already. These drugs vary in their chemical structures, action mechanisms and cellular targets, but all of them could be capable of inhibiting excessive inflammatory responses. This review summarized their chemical modifications, action mechanisms and applications of the three kinds of inhibitory oligodeoxynucleotidesin the precise treatment of immune-mediated inflammatory diseases.

Intraocular neutralizing antibodies against aflibercept in patients with age related macular degeneration

PURPOSE

To detect immunoglobulins in aqueous humour of AMD patients after repeated administration of intravitreal aflibercept.

PATIENTS AND METHODS

Twenty-one patients (age: 77.85 ± 9.21 years) previously treated with intravitreal aflibercept due to wet type age-related macular degeneration (AMD group) and 18 age-matched control subjects (age: 69.75 ± 12.67 years) were included in this study. Patients in the AMD group received a mean of 5 intravitreal injections (min: 1 max: 17) prior to the cataract surgery. Samples of aqueous humour (50 μl) were obtained by anterior chamber paracentesis as the first step of routine cataract surgery. The IgG content of the samples was analysed by an in-house developed ELISA system.

RESULTS

A significant increase in nonspecific IgG levels in the AMD group was detected compared to the control group (13.37 ± 6.65 vs. 9.44 ± 6.55 μg/ml; p = 0.03). In 11 patients, intraocular anti-aflibercept immunoglobulins could be detected (0.05 ± 0.01 μg/ml) which was significantly higher than the limit of detection for anti-aflibercept (0.04 μg/ml; p = 0.001). No correlation was found between the number of injections or the type of CNV and the aqueous level of anti-aflibercept (r = 0.02; p = 0.95).

CONCLUSION

According to our results, penetration of non-specific systemic antibodies through the impaired blood-retinal barrier is higher in patients with neovascular AMD than in subjects with an intact structural barrier. Evaluation of neutralizing antibodies to anti-VEGF agents in the aqueous humour can lead us to understanding tachyphylaxis and changes in intraocular immune mechanisms due to AMD.

OCT-Derived Radiomic Features Predict Anti-VEGF Response and Durability in Neovascular Age-Related Macular Degeneration

PURPOSE

No established biomarkers currently exist for therapeutic efficacy and durability of anti-VEGF therapy in neovascular age-related macular degeneration (nAMD). This study evaluated radiomic-based quantitative OCT biomarkers that may be predictive of anti-VEGF treatment response and durability.

DESIGN

Assessment of baseline biomarkers using machine learning (ML) classifiers to predict tolerance to anti-VEGF therapy.

PARTICIPANTS

Eighty-one participants with treatment-naïve nAMD from the OSPREY study, including 15 super responders (patients who achieved and maintained retinal fluid resolution) and 66 non-super responders (patients who did not achieve or maintain retinal fluid resolution).

METHODS

A total of 962 texture-based radiomic features were extracted from fluid, subretinal hyperreflective material (SHRM), and different retinal tissue compartments of OCT scans. The top 8 features, chosen by the minimum redundancy maximum relevance feature selection method, were evaluated using 4 ML classifiers in a cross-validated approach to distinguish between the 2 patient groups. Longitudinal assessment of changes in different texture-based radiomic descriptors (delta-texture features) between baseline and month 3 also was performed to evaluate their association with treatment response. Additionally, 8 baseline clinical parameters and a combination of baseline OCT, delta-texture features, and the clinical parameters were evaluated in a cross-validated approach in terms of association with therapeutic response.

MAIN OUTCOME MEASURES

The cross-validated area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity were calculated to validate the classifier performance.

RESULTS

The cross-validated AUC by the quadratic discriminant analysis classifier was 0.75 ± 0.09 using texture-based baseline OCT features. The delta-texture features within different OCT compartments between baseline and month 3 yielded an AUC of 0.78 ± 0.08. The baseline clinical parameters sub-retinal pigment epithelium volume and intraretinal fluid volume yielded an AUC of 0.62 ± 0.07. When all the baseline, delta, and clinical features were combined, a statistically significant improvement in the classifier performance (AUC, 0.81 ± 0.07) was obtained.

CONCLUSIONS

Radiomic-based quantitative assessment of OCT images was shown to distinguish between super responders and non-super responders to anti-VEGF therapy in nAMD. The baseline fluid and SHRM delta-texture features were found to be most discriminating across groups.

The First-Year Variation in Central Retinal Thickness Predicts Legal Blindness in Patients with Neovascular Age-Related Macular Degeneration

INTRODUCTION

Due to its progressive nature, early evaluation and timely prediction of legal blindness are important in patients with neovascular age-related macular degeneration (nAMD). We examined the association between early-stage variation in central retinal thickness (CRT) and long-term visual outcomes in patients with nAMD.

METHODS

We included 103 nAMD patients who were administered anti-vascular endothelial growth factor (anti-VEGF). Participants were considered qualified if they were (1) 50 years and older, (2) treatment-naïve, (3) received standard anti-VEGF treatment and had complete baseline information. We further excluded patients with less than 1-year follow-up data and those who experienced best corrected visual acuity ≤35. Early-stage variability in CRT was measured as the first-year coefficient of variability (CV) of CRT. Patients were then classified into the high-variability and low-variability groups according to the X-tile. A product-limit plot was used to demonstrate the differences and tested with the log-rank test. The association between first-year variability and visual outcomes was quantified using Cox regression models. Time-to-event primary endpoint was the overall visual preservation (OVP) rate, defined as the time from the first injection to legal blindness, i.e., best corrected visual acuity ≤35 Early Treatment Diabetic Retinopathy Study (ETDRS) letters.

RESULTS

A threshold of 20% of first-year CV in CRT was used to categorize 76 qualified patients into high variability (35, 46.1%) and low variability (41, 53.9%). The 5- and 10-year OVPs for patients with high versus low variability were 76% versus 48% and 59% versus 22%, respectively. High early-stage CRT variability showed a significantly higher risk of legal blindness. Even after adjusting for the demographic and clinical features, the variability remained significant (HR = 2.39, 95% CI: 1.20-4.78).

CONCLUSION

First-year variability of CRT was predictive of long-term visual outcomes in patients with nAMD, and 20% of the variability could be used as a clinically convenient threshold to qualitatively classify patients into high- and low-variability groups. The current study is important for identifying high-risk populations and for long-term disease management.

Metformin therapy as a strategy to compensate anti-VEGF resistance in patients with diabetic macular edema

Diabetic macular edema (DME) is the complication of diabetic retinopathy, the leading cause of vision loss among diabetic patients. Metformin is the main antidiabetic treatment. It is preferable for its great anti-angiogenic and anti-inflammatory effects. Anti-vascular endothelial growth factor (VEGF) therapy is the preferable treatment for DME despite its lack of convincing results in some patients. To assess whether the combination of metformin and anti-VEGF drugs may decrease the risk of anti-VEGF resistance among DME patients. We included DME patients with a central retinal thickness (CRT) ≥ 250 μm who consecutively underwent at least 3 anti-VEGF therapies from January 1, 2020, to December 30, 2021. Anti-VEGF resistance was defined as persistent macular edema with decreased CRT ≤ 25% after 3 anti-VEGF injections. 109 patients were considered for this research, of whom 65 (59.6%) were resistant to anti-VEGF therapy. The mean CRT of the non-metformin group decreased from 344.88 ± 129.48 to 318.29 ± 123.23 (20.85%) and from 415.64 ± 144.26 to 277.11 ± 99.25 (31.51%) (P = .031) in the metformin group. Moreover, the metformin group had fewer resistant patients than the non-metformin, 24 (45.3%) versus 41 (73.2%). Furthermore, a considerable gain in visual acuity was observed in both groups, with a BCVA gain of 40.41% in the metformin group and 39.9% in the non-metformin group. Metformin may be combined with an anti-VEGF drug to minimize the risk of anti-VEGF resistance among DME patients. Moreover, it can serve to design effective therapeutic deliveries.

Potential role of extracellular granzyme B in wet age-related macular degeneration and fuchs endothelial corneal dystrophy

Age-related ocular diseases are the leading cause of blindness in developed countries and constitute a sizable socioeconomic burden worldwide. Age-related macular degeneration (AMD) and Fuchs endothelial corneal dystrophy (FECD) are some of the most common age-related diseases of the retina and cornea, respectively. AMD is characterized by a breakdown of the retinal pigment epithelial monolayer, which maintains retinal homeostasis, leading to retinal degeneration, while FECD is characterized by degeneration of the corneal endothelial monolayer, which maintains corneal hydration status, leading to corneal edema. Both AMD and FECD pathogenesis are characterized by disorganized local extracellular matrix (ECM) and toxic protein deposits, with both processes linked to aberrant protease activity. Granzyme B (GrB) is a serine protease traditionally known for immune-mediated initiation of apoptosis; however, it is now recognized that GrB is expressed by a variety of immune and non-immune cells and aberrant extracellular localization of GrB substantially contributes to various age-related pathologies through dysregulated cleavage of ECM, tight junction, and adherens junction proteins. Despite growing recognition of GrB involvement in multiple age-related pathologies, its role in AMD and FECD remains poorly understood. This review summarizes the pathophysiology of, and similarities between AMD and FECD, outlines the current knowledge of the role of GrB in AMD and FECD, as well as hypothesizes putative contributions of GrB to AMD and FECD pathogenesis and highlights the therapeutic potential of pharmacologically inhibiting GrB as an adjunctive treatment for AMD and FECD.

Retinal and Choroidal Neovascularization Antivascular Endothelial Growth Factor Treatments: The Role of Gene Therapy

Neovascularization in ocular vessels causes a major disease burden. The most common causes of choroidal neovascularization (CNV) are age-related macular degeneration and diabetic retinopathy, which are the leading causes of irreversible vision loss in the adult population. Vascular endothelial growth factor (VEGF) is critical for the formation of new vessels and is the main regulator in ocular angiogenesis and vascular permeability through its receptors. Laser therapy and antiangiogenic factors have been used for CNV treatment. Bevacizumab, ranibizumab, and aflibercept are commonly used anti-VEGF agents; however, high costs and the need for frequent intraocular injections are major drawbacks of anti-VEGF drugs. Gene therapy, given the potency of one-time treatment and no need for frequent injections offers the real possibility of such a lasting treatment, with fewer adverse effects and higher patient quality of life. Herein, we reviewed the role of gene therapy in the CNV treatment. In addition, we discuss the advantages and challenges of current treatments compared with gene therapy.

Association between Polymorphisms in CFH, ARMS2, CFI, and C3 Genes and Response to Anti-VEGF Treatment in Neovascular Age-Related Macular Degeneration

Neovascular age-related macular degeneration (nAMD) is the leading cause of vision loss in the elderly. The gold standard of nAMD treatment is intravitreal injections of vascular endothelial growth factor (VEGF) inhibitors. Genetic factors may influence the response to anti-VEGF therapy and result in a high degree of response variability. The aim of the study was to evaluate the association of the polymorphisms in genes related to the complement system (rs2285714-CFI, rs10490924-ARMS2, rs2230199-C3, rs800292-CFH, and rs6677604-CFH) with nAMD its clinical features and optical coherent tomography (OCT) biomarkers of treatment response to anti-VEGF therapy. Genotyping by allele-specific PCR was performed in 193 AMD patients and 147 age-matched controls. A prospective study of the dynamics of changes in OCT biomarkers during aflibercept treatment included 110 treatment-naive patients. Allele T rs10490924 was associated with the increased risk of nAMD. For both rs800292 and rs6677604, carriage of the A allele was protective and decreased the nAMD risk. Associations of rs2230199 with central retinal thickness (CRT) and intraretinal cysts were revealed. The height of pigment epithelium detachment and the height of neuroretinal detachment were significantly higher in carriers of the minor allele of rs2285714, both at baseline and during treatment. The reduction of CRT was associated with higher CRT at baseline and the presence of the T allele of rs2285714. By the end of one-year follow-up the patients homozygous for the minor allele rs2285714 had significantly higher odds of the presence of anastomoses and loops and active neovascular membrane. Furthermore, minor allele carriers had decreased levels of complement factor I level in aqueous humor but not in the plasma, which may be due to the influence of rs2285714 on tissue-specific splicing. Our results suggest that the severity of AMD macular lesions is associated with rs2285714 and rs2230199 polymorphisms, which could be explained by their high regulatory potential. Patients with the minor allele of rs2285714 respond worse to antiangiogenic therapy.

High-Fat Diet Alters the Retinal Pigment Epithelium and Choroidal Transcriptome in the Absence of Gut Microbiota

Relationships between retinal disease, diet, and the gut microbiome have started to emerge. In particular, high-fat diets (HFDs) are associated with the prevalence and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). These effects are thought to be partly mediated by the gut microbiome, which modulates interactions between diet and host homeostasis. Nevertheless, the effects of HFDs on the retina and adjacent retinal pigment epithelium (RPE) and choroid at the transcriptional level, independent of gut microbiota, are not well-understood. In this study, we performed the high-throughput RNA-sequencing of germ-free (GF) mice to explore the transcriptional changes induced by HFD in the RPE/choroid. After filtering and cleaning the data, 649 differentially expressed genes (DEGs) were identified, with 616 genes transcriptionally upregulated and 33 genes downregulated by HFD compared to a normal diet (ND). Enrichment analysis for gene ontology (GO) using the DEGs was performed to analyze over-represented biological processes in the RPE/choroid of GF-HFD mice relative to GF-ND mice. GO analysis revealed the upregulation of processes related to angiogenesis, immune response, and the inflammatory response. Additionally, molecular functions that were altered involved extracellular matrix (ECM) binding, ECM structural constituents, and heparin binding. This study demonstrates novel data showing that HFDs can alter RPE/choroid tissue transcription in the absence of the gut microbiome.

Genetic Variants of Complement Factor H Y402H (rs1061170), C2 R102G (rs2230199), and C3 E318D (rs9332739) and Response to Intravitreal Anti-VEGF Treatment in Patients with Exudative Age-Related Macular Degeneration

Background and Objectives: To assess the association between the single nucleotide polymorphisms (SNPs) in the genes encoding complement factors CFH, C2, and C3 (Y402H rs1061170, R102G rs2230199, and E318D rs9332739, respectively) and response to intravitreal anti-vascular endothelial growth factor (VEGF) therapy in patients with exudative age-related macular degeneration (AMD). Materials and Methods: The study included 111 patients with exudative AMD treated with intravitreal bevacizumab or ranibizumab injections. Response to therapy was assessed on the basis of best-corrected visual acuity (BCVA) and central retinal thickness (CRT) measured every 4 weeks for 12 months. The control group included 58 individuals without AMD. The SNPs were genotyped by a real-time polymerase chain reaction in genomic DNA isolated from peripheral blood samples. Results: The CC genotype in SNP rs1061170 of the CFH gene was more frequent in patients with AMD than in controls (p = 0.0058). It was also more common among the 28 patients (25.2%) with poor response to therapy compared with good responders (p = 0.0002). Poor responders, especially those without this genotype, benefited from switching to another anti-VEGF drug. At the last follow-up assessment, carriers of this genotype had significantly worse BCVA (p = 0.0350) and greater CRT (p = 0.0168) than noncarriers. TT genotype carriers showed improved BCVA (p = 0.0467) and reduced CRT compared with CC and CT genotype carriers (p = 0.0194). No associations with AMD or anti-VEGF therapy outcomes for SNP rs9332739 in the C2 gene and SNP rs2230199 in the C3 gene were found. Conclusions: The CC genotype for SNP rs1061170 in the CFH gene was associated with AMD in our population. Additionally, it promoted a poor response to anti-VEGF therapy. On the other hand, TT genotype carriers showed better functional and anatomical response to anti-VEGF therapy at 12 months than carriers of the other genotypes for this SNP.

Biomarkers as Predictive Factors of Anti-VEGF Response

Age-related macular degeneration is the main cause of irreversible vision in developed countries, and intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are the current gold standard treatment today. Although anti-VEGF treatment results in important improvements in the course of this disease, there is a considerable number of patients not responding to the standardized protocols. The knowledge of how a patient will respond or how frequently retreatment might be required would be vital in planning treatment schedules, saving both resource utilization and financial costs, but today, there is not an ideal biomarker to use as a predictive response to ranibizumab therapy. Whole blood and blood mononuclear cells are the samples most studied; however, few reports are available on other important biofluid samples for studying this disease, such as aqueous humor. Moreover, the great majority of studies carried out to date were focused on the search for SNPs in genes related to AMD risk factors, but miRNAs, proteomic and metabolomics studies have rarely been conducted in anti-VEGF-treated samples. Here, we propose that genomic, proteomic and/or metabolomic markers could be used not alone but in combination with other methods, such as specific clinic characteristics, to identify patients with a poor response to anti-VEGF treatment to establish patient-specific treatment plans.

Long Non-Coding RNA PNKY Modulates the Development of Choroidal Neovascularization

Long non-coding RNAs (lncRNAs) have been widely implicated in human diseases. Our aim was to explore the regulatory role of changes in the expression levels of PNKY and its linked signaling networks in mediating stress-induced choroidal neovascularization. PNKY expression levels were reduced in mice by laser and exposure of endothelial cell to hypoxic stress. PNKY silencing exacerbated the formation of CNV in a laser-induced CNV model and an ex vivo model, while overexpression inhibited CNV development. Silencing or overexpression of PNKY altered the viability, proliferation, migration, and tube-forming capacity of endothelial cells in vitro. Mechanistically, through the lncRNA–RNA binding protein–miRNA interaction analysis involving loss of function and gain-of-function experiments, we found that lncRNA PNKY inhibited the binding of miR124 to PTBP1 and maintained the homeostasis of choroidal vascular function by promoting Bcl-2 like protein 11 (BIM), and its dysfunction led to exacerbation of CNV lesion. Therefore, this study suggests that the lncPNKY/PTBP1–miR-124 axis is involved in regulating the development of CNV, providing a potential therapeutic target for the treatment of CNV.

Novel Possible Protein Targets in Neovascular Age-Related Macular Degeneration: A Pilot Study Experiment

Age-related macular degeneration (AMD) is among the world's leading causes of blindness. In its neovascular form (nAMD), around 25% of patients present further anatomical and visual deterioration due to persistence of neovascular activity, despite gold-standard treatment protocols using intravitreal anti-VEGF medications. Thus, to comprehend, the molecular pathways that drive choroidal neoangiogenesis, associated with the vascular endothelial growth factor (VEGF), are important steps to elucidate the mechanistic events underneath the disease development. This is a pilot study, a prospective, translational experiment, in a real-life context aiming to evaluate the protein profiles of the aqueous humor of 15 patients divided into three groups: group 1, composed of patients with nAMD, who demonstrated a good response to anti-VEGF intravitreal injections during follow-up (good responsive); group 2, composed of patients with anti-VEGF-resistant nAMD, who demonstrated choroidal neovascularization activity during follow-up (poor/non-responsive); and group 3, composed of control patients without systemic diseases or signs of retinopathy. For proteomic characterization of the groups, mass spectrometry (label-free LC-MS/MS) was used. A total of 2,336 proteins were identified, of which 185 were distinctly regulated and allowed the differentiation of the clinical conditions analyzed. Among those, 39 proteins, including some novel ones, were analyzed as potential disease effectors through their pathophysiological implications in lipid metabolism, oxidative stress, complement system, inflammatory pathways, and angiogenesis. So, this study suggests the participation of other promising biomarkers in neovascular AMD, in addition to the known VEGF.

Proteomic Profiling of Aqueous Humor Exosomes from Age-related Macular Degeneration Patients

Purpose: The alteration of the exosomal proteins in the aqueous humor (AH) is linked to the development of eye diseases. The goal of this study was to examine the exosomal protein profile of patients with age-related macular degeneration (AMD) to better understand their role in the pathogenesis of AMD. Methods: Exosomes were isolated from the AH of 28 AMD and 25 control eyes. The quality, concentration, and size distribution of exosomes were measured using a nanoparticle tracking analysis system (NTA). Total exosomal proteins from each sample were purified and digested with trypsin for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Results: Based on LC-MS/MS analysis, we got 105 exosomal peptides from AMD and control patients. Gene ontology (GO) analysis in the biology process revealed that exosomal proteins of AMD were enriched in the lipoprotein metabolic process. T-test analysis revealed six exosomal proteins in patients with AMD were significantly different from controls. Comparing the exosomal protein profile of AMD patients who were receiving anti-VEGF therapy, we observed the amount of two proteins decreased with the duration of the anti-VEGF treatment time. Conclusions: In this study, we successfully isolated and purified AH exosomes. Our results provide pioneering findings for the exosomal protein profile in AMD development and under therapy. These unique proteins could be the new targets for drug discovery or biological markers for evaluating therapeutic efficacy.

Synthetic anti-angiogenic genomic therapeutics for treatment of neovascular age-related macular degeneration

In light of the intriguing potential of anti-angiogenic approach in suppressing choroidal neovascularization, we attempted to elaborate synthetic gene delivery systems encapsulating anti-angiogenic plasmid DNA as alternatives of clinical antibody-based therapeutics. Herein, block copolymer of cyclic Arg-Gly-Asp-poly(ethylene glycol)-poly(lysine-thiol) [RGD-PEG-PLys(thiol)] with multifunctional components was tailored in manufacture of core-shell DNA delivery nanoparticulates. Note that the polycationic PLys segments were electrostatically complexed with anionic plasmid DNA into nanoscaled core, and the tethered biocompatible PEG segments presented as the spatial shell (minimizing non-specific reactions in biological milieu). Furthermore, the aforementioned self-assembly was introduced with redox-responsive disulfide crosslinking due to the thiol coupling. Hence, reversible stabilities, namely stable in extracellular milieu but susceptible to disassemble for liberation of the DNA payloads in intracellular reducing microenvironment, were verified to facilitate transcellular gene transportation. In addition, RGD was installed onto the surface of the proposed self-assemblies with aim of targeted accumulation and internalization into angiogenic endothelial cells given that RGD receptors were specifically overexpressed on their cytomembrane surface. The proposed anti-angiogenic DNA therapeutics were validated to exert efficient expression of anti-angiogenic proteins in endothelial cells and elicit potent inhibition of ocular neovasculature post intravitreous administration. Hence, the present study approved the potential of gene therapy in treatment of choroidal neovascularization. In light of sustainable gene expression properties of DNA therapeutics, our proposed synthetic gene delivery system inspired prosperous potentials in long-term treatment of choroidal neovascularization, which should be emphasized to develop further towards clinical translations.

[Anti-VEGF therapy for neovascular age-related macular degeneration: causes of incomplete response]

Neovascular age-related macular degeneration (nAMD) is one of the leading causes of decreased vision in the elderly population in many countries, including Russia. Anti-VEGF therapy is undoubtedly the «gold standard» of treatment for the disease, but its use in different patients is known to produce results with significant interindividual differences. This article reviews modern ideas about the clinical assessment of the degree of response to anti-VEGF therapy, possible reasons for its insufficient effectiveness (clinical, pharmacological, or related to nAMD pathogenesis), discusses the potential applications of the existing therapeutic strategies, and considers the prospects for the emergence of new strategies that could be used for solving that problem.

Effect of Probenecid on Endothelial Cell Growth Rate and Retinal Angiogenesis in an Oxygen-Induced Retinopathy Model

Objectives: Probenecid is an anion transport inhibitor, which, according to the connectivity map (CMap; a biological application database), interferes with hypoxia-induced gene expression changes in retinal vascular endothelial cells (ECs). Here, we investigated the influence of probenecid on retinal EC cytotoxicity and retinal neovascularization in a murine oxygen-induced retinopathy (OIR) model.

Methods: The retinal EC growth rate in the presence of hypoxia-mimicking concentrations of cobalt chloride (CoCl₂) was determined using the thiazolyl blue tetrazolium bromide (MTT) assay and proliferating cell nuclear antigen (PCNA) expression. In OIR rats, probenecid was administered by intraperitoneal injection (i.p.) from postnatal day (P) 1 to P7. The concentrations of vitreous humor vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1α, and placental growth factor (PlGF) were determined by using the ELISA kit at P21. The amount of newly formed vascular lumen was evaluated by histopathological examination. Retinopathy and neovascularization were assessed by scoring isolectin B4 fluorescein–stained retinal flat mounts. Western blots for liver tissue HIF-1α and hepcidin (HAMP) were performed.

Results:In vitro, probenecid led to the recession of the hypoxia-induced EC growth rate. In vivo, compared to the OIR retina, the upregulation of VEGF, HIF-1α, and PlGF in phase II retinopathy of prematurity (ROP) was inhibited by probenecid administration. Moreover, probenecid ameliorated neovascularization and resulted in significantly reduced relative leakage fluorescence signal intensity in fluorescein-stained retinal flat mounts (p < 0.05). Probenecid alleviated the liver overactivation of HAMP and downregulation of HIF-1α in OIR rats.

Conclusions: This is the first demonstration that implies that probenecid might be a protective compound against retinal angiogenesis in OIR. These changes are accompanied with decreased hyperoxia-mediated hepcidin overproduction. Although the relevance of the results to ROP needs further research, these findings may help establish potential pharmacological targets based on the CMap database.

Inhibition of Vascular Growth by Modulation of the Anandamide/Fatty Acid Amide Hydrolase Axis

Supplemental Digital Content is available in the text.

Objective:

Pathological angiogenesis is a hallmark of various diseases characterized by local hypoxia and inflammation. These disorders can be treated with inhibitors of angiogenesis, but current compounds display a variety of side effects and lose efficacy over time. This makes the identification of novel signaling pathways and pharmacological targets involved in angiogenesis a top priority.

Approach and Results:

Here, we show that inactivation of FAAH (fatty acid amide hydrolase), the enzyme responsible for degradation of the endocannabinoid anandamide, strongly impairs angiogenesis in vitro and in vivo. Both, the pharmacological FAAH inhibitor URB597 and anandamide induce downregulation of gene sets for cell cycle progression and DNA replication in endothelial cells. This is underscored by cell biological experiments, in which both compounds inhibit proliferation and migration and evoke cell cycle exit of endothelial cells. This prominent antiangiogenic effect is also of pathophysiological relevance in vivo, as laser-induced choroidal neovascularization in the eye of FAAH^−/− mice is strongly reduced.

Conclusions:

Thus, elevation of endogenous anandamide levels by FAAH inhibition represents a novel antiangiogenic mechanism.

Efficacy of Anti-Vascular Endothelial Growth Factor Treatment in Neovascular Age-Related Macular Degeneration and Systemic Cardiovascular Risk Factors

This study evaluates whether the presence of cardiovascular risk factors (CRFs) affects functional and morphological responses to anti–vascular endothelial growth factor (VEGF) therapy in patients with neovascular age-related macular degeneration (nAMD). Retrospective analysis included 98 treatment-naïve eyes followed for at least 12 months. Patients received intravitreal injections of ranibizumab or aflibercept with the dosage and regimen set according to each manufacturer’s recommendations for their product. Parameters evaluated at each follow-up visit included best-corrected visual acuity and central retinal thickness. Additionally, the presence of the following CRFs was evaluated: male sex, age of older than 70 years, history of current or past smoking, systemic arterial hypertension, diabetes mellitus, total hypercholesterolemia, low-density lipoprotein hypercholesterolemia, high-density lipoprotein concentration of 45 mg/dL or less, atherogenic dyslipidemia, family history of cardiovascular disease, and chronic kidney disease. A statistically significant better letter gain in visual acuity (p = 0.012) and greater percentage of responders (p = 0.035)—that is patients in whom best corrected visual acuity was stabilized or improved at 12 months—were noted among patients without a diagnosis of arterial hypertension. A statistically significant better mean visual improvement was also achieved in patients with higher total cholesterol plasma levels (p = 0.004), but this finding was not reflected in the significantly higher percentage of responders. The presence of remaining analyzed risk factors did not substantially affect the results of treatment. Systemic arterial hypertension is an independent factor leading to a poor functional outcome following anti-VEGF therapy in patients with nAMD. Effects of anti-VEGF treatment in patients with high total cholesterol levels should be analyzed in further research.

Inhibition of APE1/Ref-1 for Neovascular Eye Diseases: From Biology to Therapy

Proliferative diabetic retinopathy (PDR), neovascular age-related macular degeneration (nvAMD), retinopathy of prematurity (ROP) and other eye diseases are characterized by retinal and/or choroidal neovascularization, ultimately causing vision loss in millions of people worldwide. nvAMD and PDR are associated with aging and the number of those affected is expected to increase as the global median age and life expectancy continue to rise. With this increase in prevalence, the development of novel, orally bioavailable therapies for neovascular eye diseases that target multiple pathways is critical, since current anti-vascular endothelial growth factor (VEGF) treatments, delivered by intravitreal injection, are accompanied with tachyphylaxis, a high treatment burden and risk of complications. One potential target is apurinic/apyrimidinic endonuclease 1/reduction-oxidation factor 1 (APE1/Ref-1). The multifunctional protein APE1/Ref-1 may be targeted via inhibitors of its redox-regulating transcription factor activation activity to modulate angiogenesis, inflammation, oxidative stress response and cell cycle in neovascular eye disease; these inhibitors also have neuroprotective effects in other tissues. An APE1/Ref-1 small molecule inhibitor is already in clinical trials for cancer, PDR and diabetic macular edema. Efforts to develop further inhibitors are underway. APE1/Ref-1 is a novel candidate for therapeutically targeting neovascular eye diseases and alleviating the burden associated with anti-VEGF intravitreal injections.

Role of Activating Transcription Factor 4 in Murine Choroidal Neovascularization Model

Neovascular age-related macular degeneration (nAMD) featuring choroidal neovascularization (CNV) is the principal cause of irreversible blindness in elderly people in the world. Integrated stress response (ISR) is one of the intracellular signals to be adapted to various stress conditions including endoplasmic reticulum (ER) stress. ISR signaling results in the upregulation of activating transcription factor 4 (ATF4), which is a mediator of ISR. Although recent studies have suggested ISR contributes to the progression of some age-related disorders, the effects of ATF4 on the development of CNV remain unclear. Here, we performed a murine model of laser-induced CNV and found that ATF4 was highly expressed in endothelial cells of the blood vessels of the CNV lesion site. Exposure to integrated stress inhibitor (ISRIB) reduced CNV formation, vascular leakage, and the upregulation of vascular endothelial growth factor (VEGF) in retinal pigment epithelium (RPE)-choroid-sclera complex. In human retinal microvascular endothelial cells (HRMECs), ISRIB reduced the level of ATF4 and VEGF induced by an ER stress inducer, thapsigargin, and recombinant human VEGF. Moreover, ISRIB decreased the VEGF-induced cell proliferation and migration of HRMECs. Collectively, our findings showed that pro-angiogenic effects of ATF4 in endothelial cells may be a potentially therapeutic target for patients with nAMD.