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

Metformin inhibits subretinal fibrosis by activating Klotho by miR-126-5p

Subretinal fibrosis is a main cause of visual loss in patients with neovascular age-related macular degeneration (nAMD), for whom there has been a lack of effective medication. Metformin can improve inflammation and angiogenesis in eye diseases. This study aimed to investigate the mechanism by which metformin inhibits subretinal fibrosis. A subretinal fibrosis cell model was induced by treating human retinal pigment epithelial cells (ARPE-19) with TGF-β1, a subretinal fibrosis mouse model was induced by a laser, and both cells and mice were treated with metformin. Cell proliferation, migration, and invasion were detected by CCK-8, scratch, and Transwell assays. Western blotting and immunofluorescence were used to evaluate protein expression levels, and RT‒qPCR was used to detect gene expression levels. HE and Masson staining were used to observe the morphological changes in retinal and choroidal tissues. Metformin treatment inhibited the TGF-β1-induced proliferation, migration, invasion and epithelial‒mesenchymal transition (EMT) of ARPE-19 cells and effectively ameliorated laser-induced subretinal fibrosis in mice. Mechanistically, metformin inhibits the expression of miR-126-5p, promotes Klotho synthesis, slows the progression of subretinal fibrosis, and miR-126-5p targets and negatively regulates Klotho. Metformin activates Klotho by inhibiting miR-126-5p, thereby reversing TGF-β1-induced ARPE-19 cell EMT and improving laser-induced subretinal fibrosis in mice.

Treating or tolerating persistent subretinal fluid in neovascular age-related macular degeneration: a systematic review of visual and anatomical outcomes with anti-VEGF therapy

PURPOSE

The management of persistent subretinal fluid (SRF) in neovascular age-related macular degeneration (nAMD) varies, with no comprehensive review of outcomes from different treatment approaches. This systematic review evaluates the efficacy of interventions for managing persistent SRF in nAMD patients.

METHODS

Using a structured search strategy, a systematic review examined anti-vascular endothelial growth factor (VEGF) treatments for nAMD with persistent SRF. After removing duplicates, 861 articles were screened, 255 underwent full-text review, and 19 met the eligibility criteria.

RESULTS

The included studies demonstrated variable outcomes regarding the management of persistent SRF in nAMD. Several studies supported tolerating SRF, showing no significant difference in visual acuity between patients with and without persistent SRF. Conversely, some studies advocated for more aggressive treatment, demonstrating a significant reduction in SRF and potential visual benefits. Patients with SRF generally have better visual outcomes compared to those with intraretinal fluid or cysts. High-frequency anti-VEGF regimens, especially with aflibercept, reduce SRF and maintain visual acuity. However, less aggressive protocols achieve stable outcomes with fewer injections.

CONCLUSION

Persistent SRF in nAMD does not necessarily lead to worse visual outcomes. Standardized protocols and further research are needed to improve management strategies.

Selective Gamma-Secretase Inhibition by CHF5074 Attenuates Inflammation and Neovascularization in a Murine Model of Choroidal Neovascularization

PURPOSE

Chronic inflammation plays an important role in the pathogenesis of choroidal neovascularization (CNV). This study aimed to investigate the effect of the CHF5074, a γ-secretase inhibitor, on angiogenesis in a laser-induced CNV model and elucidate its possible molecular mechanism.

METHODS

Male C57/BL6J mice aged between 6 to 8 weeks were employed to set up a laser-induced model of CNV. Then, CHF5074 was injected intraperitoneally on the day after laser modeling, as well as on the second, third, and fourth days. Immunofluorescence staining was used to evaluate the retinal and choroidal complex. The markers used were CD31 for neovascularization and IBA1 for microglia staining in ocular tissue slices. Fundus fluorescein angiography on days 3d, 7d, and 14d analyzed neovascularization and leakage areas. Inflammatory indicators were examined by Western blot (WB) and enzyme-linked immunosorbent assay (ELISA). High-throughput whole-tissue sequencing of retinal choroids identified relevant cell pathways. Key regulatory factors modulated by CHF5074 were identified via WB. Co-culture of BV2 cells and human umbilical vein endothelial cells (HUVEC) were used to explore the function of CHF5074 on the inhibition of tube formation.

RESULTS

CHF5074 significantly decreased CD31 expression in the choroid on 3d, 7d, and 14d post-laser modeling (p < 0.05) and decreased both neovascularization and leakage areas (p < 0.05). Additionally, CHF5074 significantly lowered TNF-α, IL-10, and IL-1β expression levels in the choroid (p < 0.05), as demonstrated by WB analysis and ELISA. High-throughput whole-tissue sequencing identified P38-MAPK, JNK, and Wnt signaling pathways associated with neovascularization. CHF5074 decreased P38 protein phosphorylation (p < 0.05) as confirmed by WB analysis. CHF5074 inhibited the tube formation of HUVECs co-cultured with LPS and ATP-treated BV2 cells.

CONCLUSION

CHF5074 significantly suppresses angiogenesis in laser-induced choroidal neovascularization models, suggesting its potential as a novel agent for preventing and treating CNV.

Efficacy and safety of brolucizumab every 6 weeks induction therapy for neovascular age-related macular degeneration

This retrospective study aims to evaluate the short-term efficacy and safety of brolucizumab every 6 weeks induction therapy for neovascular age-related macular degeneration (nAMD) cases. This study included 140 eyes from 140 patients (101 males and 39 females, with a mean age of 77.7 ± 8.7 years) with nAMD who received brolucizumab injections every 6 weeks as part of induction therapy across four participating centers between June 2020 and March 2024. Follow-up lasted for at least 20-24 weeks. Data collected included age, sex, history of nAMD treatment, best-corrected visual acuity (BCVA), central retinal thickness (CRT), presence or absence of exudation, and occurrence of intraocular inflammation (IOI). Sixty-one eyes had prior nAMD treatment. Mean BCVA (logMAR) was 0.40 ± 0.43 before brolucizumab therapy, improving to 0.38 ± 0.42, 0.33 ± 0.41, and 0.34 ± 0.44 after the first, second, and third injections, respectively. Significant improvements in BCVA were observed from the second injection onward (p < 0.05). CRT decreased significantly from baseline of 341.6 ± 151.0 to 219.1 ± 119.8, 204.0 ± 112.9, and 200.8 ± 96.0 after the first, second, and third injections, respectively (p < 1.0 × 10-20). Exudative findings, present in all cases before treatment, resolved in 64.3%, 82.1%, and 79.3% of cases after the first, second, and third injections, respectively. IOI was observed in five, three, and four eyes after the first, second, and third injections, respectively, accounting for 8.6% of all cases. No cases had retinal vasculitis or occlusion. In conclusion, brolucizumab administered every 6 weeks as induction therapy for nAMD showed favorable efficacy and safety outcomes during a 6-month follow-up.

Ref-1 redox activity regulates retinal neovascularization by modulating transcriptional activation of HIF-1α

Retinal neovascularization impairs visual function and is a hallmark of several neovascular eye diseases, including retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Current treatments include intravitreal injections of anti-vascular endothelial growth factor (VEGF) biologics, but these therapeutics are often accompanied by high treatment burden and resistance to therapy. Prior studies indicate that APE1/Ref-1, a multifunctional protein with both endonuclease (APE1) and redox-mediated transcriptional regulatory activity (Ref-1), activates multiple pro-angiogenic and pro-inflammatory signaling pathways by chemically reducing key cysteine residues in transcription factors, thereby activating them. Here, we investigated the previously unexplored role of Ref-1 in retinal neovascularization. We demonstrate that Ref-1 is highly expressed in endothelial cells in human PDR and in the oxygen-induced retinopathy (OIR) mouse model of retinal neovascularization. Ref-1 is also highly expressed in microglia and astrocytes in OIR. A small molecule Ref-1 redox inhibitor, APX2009, decreased retinal neovascularization in OIR after systemic delivery. In vitro, hypoxic endothelial cells did not exhibit upregulation of Ref-1 but rather increased Ref-1 nuclear localization. APX2009 decreased hypoxic endothelial cell proliferation and HIF-1α transcriptional activation. Thus, Ref-1 redox activity may be a novel therapeutic target for the treatment of retinal neovascularization, making APX2009 a promising systemic therapeutic approach for the treatment of vascular retinopathies such as ROP and PDR.

Endothelial AGGF1 promotes retinal angiogenesis by coordinating TNFSF12/FN14 signalling

Abnormal angiogenesis is a key process associated with ischaemic retinopathies such as diabetic retinopathy, for which the underlying pathological mechanisms are still poorly understood. Here, we confirm that angiogenic factor 1 with a G patch and FHA domain (AGGF1) is elevated in the diabetics and induces retinal angiogenesis. Mechanistic investigations demonstrate that HIF-1α directly regulates AGGF1 expression. AGGF1 upregulates the expression of cell cycle proteins by increasing the binding of tumour necrosis factor ligand superfamily member 12 (TNFSF12) to fibroblast -growth -factor-inducible 14 (FN14, TNFRSF12A). Furthermore, targeting AGGF1 attenuates pathological neovascularisation in ischaemic retinopathy. Additionally, we discover that sodium-glucose cotransporter 2 inhibitors (SGLT2i) could inhibit the AGGF1 signalling pathway early to achieve therapeutic effects. Overall, we elucidate the mechanism underlying pathological retinal angiogenesis involved in endothelial AGGF1-dependent events and highlight a therapy for the effective treatment of ischaemic retinopathy.

Targeting Runx1 in Pathological Retinal Angiogenesis: A Potential Therapeutic Approach

Purpose

Neovascular eye diseases, such as proliferative diabetic retinopathy (PDR), wet age-related macular degeneration (wAMD) and retinopathy of prematurity (ROP), are major causes of vision loss and blindness worldwide. Our transcription factor motif enrichment analysis highlighted RUNX1 as a key regulator in the hypoxic response. The purpose of this study was to characterize how loss of Runx1 affects physiological and pathological retinal vasculature formation.

Methods

RNA-seq analysis and Transcription factor motif enrichment analysis were conducted in hypoxic and normoxic HUVECs. Conditional deletion of Runx1 in endothelial cells In mice was achieved using recombinase driver Cdh5-CreERT2. Vascular coverage, density, vessel progression, branchpoints, and sprout numbers was measured in retina of Runx1iECKO mice. The expression patterns, functions, and potential therapeutic value of RUNX1 were further explored with clinical samples, as well as in vivo and in vitro experiments. Bioinformatics and high-throughput sequencing were performed to identify potential target genes of Runx1. RT-qPCR and Western blot analyses were carried out to detect the changes of PI3-kinase/AKT/mTOR pathway.

Results

Loss of Runx1 in mice resulted in a reduction of the vascular coverage, density, vessel progression, branchpoints, and sprouts numbers of the retinal vascular network during its development. Notably, mature blood vessels remained unaffected by Runx1 inhibition. Upregulation of RUNX1 was observed in patients with PDR and ROP. RUNX1 Inhibition reduced endothelial cell proliferation, migration and tubule formation, leading to decreased pathological neovascularization, which is shown in oxygen-induced retinopathy. Mechanistically, in vitro experiments demonstrated that RUNX1 regulates EC angiogenesis through the PI3K/AKT/mTOR signaling pathway.

Conclusions

Runx1 is essential for physiological retinal vascularization. RUNX1 Inhibition may effectively decrease pathological neovascularization. Our findings suggest that targeting RUNX1 could be a promising therapeutic strategy for retinal neovascular disorders, preserving the integrity of mature blood vessels while selectively inhibiting neovascularization.

Geraniin Alleviates Mouse Laser-Induced Choroidal Neovascularisation by Inhibiting Choroidal Endothelial Cell ACE2/Ang-(1-7)/MasR/IL-10 Pathway

Anti-vascular endothelial growth factor (VEGF) drugs suppress choroidal neovascularisation (CNV), thus improving vision. However, some patients may have a poor response or develop resistance to anti-VEGF drugs. Geraniin (GE), a polyphenol isolated from an herb called Phyllanthus amarus, possesses anti-angiogenic properties. This study aimed to explore the mechanism of action of GE in CNV. GE was found to activate the angiotensin-converting enzyme 2 (ACE2)/angiotensin 1-7 (Ang-[1-7])/MAS1 proto-oncogene, G protein-coupled receptor (MasR)/interleukin-10 (IL-10) pathway in hypoxic human choroidal endothelial cells (HCECs) in vitro and mouse models of laser-induced CNV in vivo. Activation of the ACE2/Ang-(1-7)/MasR/IL-10 pathway by GE attenuated the proliferative, migratory, and tube-forming abilities of hypoxic HCECs and prevented the development of CNV in mice. Notably, GE did not cause ocular or systemic toxicity in mice with CNV. These findings suggest that GE alleviates CNV by activating the ACE2/Ang-(1-7)/MasR/IL-10 pathway in choroidal endothelial cells (CECs).

Simultaneous Intravitreal Steroid and Anti-VEGF Therapy for Monotherapy-Resistant Chronic Wet Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE

The purpose of this study was to analyze the safety and efficacy of combined intravitreal anti-vascular endothelial growth factor (anti-VEGF) and steroid therapeutic agents for resistant choroidal neovascularization (CNV). A retrospective observational clinical study was performed assessing anatomic and visual changes in a consecutive cohort of patients with refractory chronic wet age-related macular degeneration resistant to high-dose aflibercept therapy.

PATIENTS AND METHODS

Twelve eyes of 12 patients with unresponsive CNV despite aggressive monthly anti-VEGF (4-mg aflibercept [mean: 43.75 ± SD23.08]) were included. Combination consisted of simultaneous administration of anti-VEGF and corticosteroids. Study measures evaluated visual acuity, central retinal thickness (CRT), and intraocular pressure.

RESULTS

Paired tests revealed significant CRT reduction from the baseline at the 1-month (388.58 ± 89.31 versus 334.00 ± 92.88, P = 0.0117), 2-month (388.58 ± 89.31 versus 312.08 ± 75.61, P = 0.0185), and 3-month (388.53 ± 89.31 versus 304.56 ± 53.28, P = 0.046) visit. The Kaplan-Meier curve showed a median time of remission (no retinal fluid) of 70 days (95% CI 53, 147 days).

CONCLUSION

Combination treatment demonstrated clear anatomic improvement in eyes with anti-VEGF-resistant CNV. [Ophthalmic Surg Lasers Imaging Retina 2024;55:698-704.].

Two-year efficacy and safety of different anti-vascular endothelial growth factor regimens for neovascular age-related macular degeneration: a network meta-analysis of randomized controlled trials

OBJECTIVES

To compare the 2-year efficacy and safety of various anti-vascular endothelial growth factor (VEGF) regimens for neovascular age-related macular degeneration (nAMD).

METHODS

A comprehensive search was performed on multiple electronic databases up to April 2023 and updated in June 2024, to identify relevant randomized controlled trials (RCTs). Key outcomes included the proportion of patients achieving a vision gain of ≥15 letters and maintaining stable vision (loss of <15 letters) in best-corrected visual acuity (BCVA), changes in mean BCVA from baseline, serious ocular adverse events (SAEs), adverse events leading to treatment discontinuation and any cause of death at 2 years.

RESULTS

Nineteen trials with 12,654 patients and 25 treatment regimens were analyzed in the study. All anti-VEGF regimens showed superior efficacy compared to sham therapy. Specifically, faricimab 6 mg (4+up to Q16W) and ranibizumab 0.5 mg (2-week T&E) displayed top-level effect in vision gain. Bevacizumab 1.25 mg (2-week T&E) and aflibercept 2 mg (2-week T&E) demonstrated the most stable vision outcomes. Bevacizumab 1.25 mg (2-week T&E) and ranibizumab 0.5 mg (2-week T&E) exhibited the most pronounced mean BCVA improvement. Compared to sham therapy, the risk of SAEs was significantly higher for brolucizumab 6 mg (3 + Q12W/ Q8W) (RR = 6.04, 95% CI: 1.30-28.02) and PDS 100 mg/ml (Q24W) (RR = 10.95, 95% CI: 2.14-56.02), but not for other anti-VEGF regimens.

CONCLUSIONS

Ranibizumab 0.5 mg (2-week T&E) emerges as a potentially optimal regimen for nAMD over a 2-year period. Future studies need to consider the impact of baseline characteristics on treatment outcomes.

Durability and Efficacy of Faricimab in Treatment-Resistant Retinal Edema Utilizing "Real-World" Dosing Regimens

Purpose: To retrospectively analyze clinical outcomes of patients with "treatment-resistant" neovascular age-related macular degeneration or diabetic macular edema who were switched to intravitreal faricimab injections (IFIs) using a "real-world" treat-and-extend (TAE) protocol. Methods: Seventy-one eyes from 62 patients receiving antivascular endothelial growth factor injections were evaluated before and after switching to IFI. Demographic and clinical data were collected. Primary endpoints were treatment interval extension and presence of intraretinal or subretinal fluid on spectral-domain optical coherence tomography (OCT) after switching to IFI. Secondary endpoints included best-corrected visual acuity, average OCT central subfield thickness, and presence of a pigment epithelium detachment and pigment epithelium detachment height. Results: The average treatment interval after switching to IFI significantly increased from 37.6 ± 10.8 days to 45.2 ± 16.6 days (p = 0.0016). At the last follow-up, 35% of eyes were able to achieve a fluid-free status post-IFI. A chi-square test of independence validated this finding by showing a significant difference in the OCT findings trending towards less or no fluid on follow-up (X 2 [3, N = 71] = 13.0705; p = 0.0003). The average central subfield thickness decreased from 327.2 ± 89.1 μm to 294.8 ± 86.5 μm (p = 0.0294). Best-corrected visual acuity, intraocular pressure, pigment epithelium detachment presence, and height had no significant difference after switching to IFI. Conclusions: In "treatment-resistant" patients receiving anti-VEGF therapy for neovascular age-related macular degeneration or diabetic macular edema, switching to IFI in a "real-world" TAE protocol led to statistically significant improvements in treatment interval and retinal fluid on spectral domain OCT.

Efficacy of Anti-Vascular Endothelial Growth Factor (VEGF) Therapy for Age-Related Macular Degeneration

Anti-vascular endothelial growth factor (VEGF) drugs are used for various diseases with abnormal proliferation of blood vessels. The use of these drugs in wet age-related macular degeneration (AMD) has proven to be highly effective. Various factors contribute to the efficacy of these drugs in different settings. Many studies have proven that these drugs effectively slow disease progress and improve visual outcomes. Factors contributing to the success or failure of the treatment include the genetic makeup of the patient, comorbidities, compliance with the clinic visits and injections, long-term follow-up for the treatment, socioeconomic status, and availability of different drugs. The treatment of choroidal neovascularization (CNV) in neovascular age-related macular degeneration (nAMD) has been revolutionized after the introduction of anti-VEGF therapy. However, there are still some gaps in the literature that require the attention of the researchers. Our literature review has evaluated anti-VEGF use over the years and analyzed the efficiency of drugs in different settings. It showed that all the anti-VEGF drugs depict similar visual results for one to two years. The long-term evaluation of any drug cannot be commented on yet and needs further evidence through different research. These drugs improve visual function and the anatomical results of patients with other eye problems. These drugs' adverse effects are rare but still an important point requiring further research. Clinical outcomes of the drugs must be ascertained through patients' eyes to assess the quality of life improvement appropriately. The cost-effectiveness of the drugs is a substantial debatable topic, as bevacizumab is cost-effective but still requires Food and Drug Administration (FDA) approval.

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.

Intravitreal Metformin Protects Against Choroidal Neovascularization and Light-Induced Retinal Degeneration

Neovascular age-related macular degeneration (nAMD), a leading cause of blindness in older adults, presents a challenging pathophysiology involving choroidal neovascularization (CNV) and retinal degeneration. Current treatments relying on intravitreal (IVT) administration of anti-angiogenic agents are costly and of moderate effectiveness. Metformin, the common anti-diabetic drug, has been associated with decreased odds of developing AMD. Studies have shown that metformin can mitigate cellular aging, neoangiogenesis, and inflammation across multiple diseases. This preclinical study assessed metformin's impact on vessel growth using choroidal explants before exploring IVT metformin's effects on laser-induced CNV and light-induced retinal degeneration in C57BL/6J and BALB/cJ mice, respectively. Metformin reduced new vessel growth in choroidal explants in a dose-dependent relationship. Following laser induction, IVT metformin suppressed CNV and decreased peripheral infiltration of IBA1+ macrophages/microglia. Furthermore, IVT metformin protected against retinal thinning in response to light-induced degeneration. IVT metformin downregulated genes in the choroid and retinal pigment epithelium which are associated with angiogenesis and inflammation, two key processes that drive nAMD progression. These findings underscore metformin's capacity as an anti-angiogenic and neuroprotective agent, demonstrating this drug's potential as an accessible option to help manage nAMD.

Dry age-related macular degeneration classification from optical coherence tomography images based on ensemble deep learning architecture

Background

Dry age-related macular degeneration (AMD) is a retinal disease, which has been the third leading cause of vision loss. But current AMD classification technologies did not focus on the classification of early stage. This study aimed to develop a deep learning architecture to improve the classification accuracy of dry AMD, through the analysis of optical coherence tomography (OCT) images.

Methods

We put forward an ensemble deep learning architecture which integrated four different convolution neural networks including ResNet50, EfficientNetB4, MobileNetV3 and Xception. All networks were pre-trained and fine-tuned. Then diverse convolution neural networks were combined. To classify OCT images, the proposed architecture was trained on the dataset from Shenyang Aier Excellence Hospital. The number of original images was 4,096 from 1,310 patients. After rotation and flipping operations, the dataset consisting of 16,384 retinal OCT images could be established.

Results

Evaluation and comparison obtained from three-fold cross-validation were used to show the advantage of the proposed architecture. Four metrics were applied to compare the performance of each base model. Moreover, different combination strategies were also compared to validate the merit of the proposed architecture. The results demonstrated that the proposed architecture could categorize various stages of AMD. Moreover, the proposed network could improve the classification performance of nascent geographic atrophy (nGA).

Conclusion

In this article, an ensemble deep learning was proposed to classify dry AMD progression stages. The performance of the proposed architecture produced promising classification results which showed its advantage to provide global diagnosis for early AMD screening. The classification performance demonstrated its potential for individualized treatment plans for patients with AMD.

Bruton's tyrosine kinase inhibition suppresses pathological retinal angiogenesis

BACKGROUND AND PURPOSE

Pathological retinal angiogenesis is a typical manifestation of vision-threatening ocular diseases. Many patients exhibit poor response or resistance to anti-vascular endothelial growth factor (VEGF) agents. Bruton's tyrosine kinase (BTK) controls the proliferation and function of immune cells. Therefore, we examined the anti-inflammatory and anti-angiogenic effects of BTK inhibition on retinal angiogenesis.

EXPERIMENTAL APPROACH

Retinal neovascularisation and vascular leakage in oxygen-induced retinopathy in C57/BL6J mice were assessed by whole-mount retinal immunofluorescence. PLX5622 was used to deplete microglia and Rag1-knockout mice were used to test the contribution of lymphocytes to the effects of BTK inhibition. The cytokines, activation markers, inflammatory and immune-regulatory activities of retinal microglia/macrophages were detected using qRT-PCR and immunofluorescence. NLRP3 was detected by western blotting, and the effects of BTK inhibition on the co-culture of microglia and human retinal microvascular endothelial cells (HRMECs) were examined.

KEY RESULTS

BTK inhibition suppressed pathological angiogenesis and vascular leakage, and significantly reduced retinal inflammation, which involved microglia/macrophages but not lymphocytes. BTK inhibition increased anti-inflammatory factors and reduced pro-inflammatory cytokines that resulted from NLRP3 inflammasome activation. BTK inhibition suppressed the inflammatory activity of microglia/macrophages, and acted synergistically with anti-VEGF without retinal toxicity. Moreover, the supernatant of microglia incubated with BTK-inhibitor reduced the proliferation, tube formation and sprouting of HRMECs.

CONCLUSION AND IMPLICATIONS

BTK inhibition suppressed retinal neovascularisation and vascular leakage by modulating the inflammatory activity of microglia and macrophages. Our study suggests BTK inhibition as a novel and promising approach for alleviating pathological retinal angiogenesis.

Inhibitory Effect of Phenolic Compounds on Vascular Endothelial Growth Factor-Induced Retinal Endothelial Permeability and Angiogenesis

Age-related macular degeneration (AMD), often triggered by endothelial barrier disruption through vascular endothelial growth factor (VEGF), is a leading cause of blindness. This study investigated the inhibitory effects of phenolic compounds on VEGF-induced endothelial cell proliferation, migration, angiogenesis, and permeability using human retinal microvascular endothelial cells (hRECs). Thirty-seven polyphenolic compounds were selected from various databases based on their antioxidant properties, abundance in food, and solubility. These compounds significantly reduced migration, tube formation, and endothelial permeability in VEGF-stimulated hRECs. Notably, formononetin, eriodictyol, biochanin A, and p-coumaric acid were more effective in suppressing VEGF-induced angiogenesis and endothelial permeability than lutein. Molecular docking simulations revealed that formononetin, eriodictyol, and biochanin A had relatively lower binding energies with VEGF receptor 2 (VEGFR2) than lutein and sorafenib. These findings highlight the potential of phenolic compounds to be used as VEGFR2 inhibitors and an alternative strategy for preventing AMD.

Extended siponimod release via low-porosity PLGA fibres: a comprehensive three-month in vitro evaluation for neovascular ocular diseases

Neovascular ocular diseases are among the most common causes of preventable or treatable vision loss. Their management involves lifelong, intravitreal injections of anti-vascular endothelial growth factor (VEGF) therapeutics to inhibit neovascularization, the key pathological step in these diseases. Anti-VEGF products approved for ocular administration are expensive biological agents with limited stability and short half-life. Additionally, their therapeutic advantages are hindered by high treatment resistance, poor patient compliance and the need for frequent, invasive administration. Herein, we used electrospinning to develop a unique, non-porous, PLGA implant for the ocular delivery of siponimod to improve ocular neovascular disease management. Siponimod is an FDA-approved drug for multiple sclerosis with a novel indication as a potential ocular angiogenesis inhibitor. The electrospinning conditions were optimised to produce a microfibrous, PLGA matte that was cut and rolled into the desired implant size. Physical characterisation techniques (Raman, PXRD, DSC and FTIR) indicated siponimod was distributed uniformly within the electrospun fibres as a stabilised, amorphous, solid dispersion with a character modifying drug-polymer interaction. Siponimod dispersion and drug-polymer interactions contributed to the formation of smooth fibres, with reduced porous structures. The apparent reduced porosity, coupled with the drug's hydrophobic dispersion, afforded resistance to water penetration. This led to a slow, controlled, Higuchi-type drug diffusion, with ∼30% of the siponimod load released over 90 days. The released drug inhibited human retinal microvascular endothelial cell migration and did not affect the cells' metabolic activity at different time points. The electrospun implant was physically stable after incubation under stress conditions for three months. This novel siponimod intravitreal implant broadens the therapeutic possibilities for neovascular ocular diseases, representing a potential alternative to biological, anti-VEGF treatments due to lower financial and stability burdens. Additionally, siponimod interaction with PLGA provides a unique opportunity to sustain the drug release from the electrospun fibres, thereby reducing the frequency of intravitreal injection and improving patient adherence.

Enzyme-Responsive DNA Origami-Antibody Conjugates for Targeted and Combined Therapy of Choroidal Neovascularization

Monotherapy, especially the use of antibodies targeting vascular endothelial growth factor (VEGF), has shown limitations in treating choroidal neovascularization (CNV) since reactive oxygen species (ROS) also exacerbate CNV formation. Herein, we developed a combination therapy based on a DNA origami platform targeting multiple components of ocular neovascularization. Our study demonstrated that ocular neovascularization was markedly suppressed by intravitreal injection of a rectangular DNA origami sheet modified with VEGF aptamers (Ap) conjugated to an anti-VEGF antibody (aV) via matrix metalloproteinase (MMP)-cleavable peptide linkers in a mouse model of CNV. Typically, the DNA origami-based therapeutic platform selectively accumulates in neovascularization lesions owing to the dual-targeting ability of the aV and Ap, followed by the cleavage of the peptide linker by MMPs to release the antibody. Together, the released antibody and Ap inhibited VEGF activity. Moreover, the residual bare DNA origami could effectively scavenge ROS, reducing oxidative stress at CNV sites and thus maximizing the synergistic effects of inhibiting neovascularization.

Design and Assessment of First-Generation Heterobifunctional PPARα/STING Modulators

Inflammatory retinal diseases such as diabetic retinopathy (DR) and age-related macular degeneration (AMD) are prominent causes of blindness in industrialized countries. The complexity of these diseases, involving diverse cell types and pathways that give rise to a multifactorial pathogenesis, complicates drug discovery. As such, therapies exhibiting polypharmacology are expected to improve outcomes through broader disease stage coverage and beneficial spatiotemporal effects. We report herein the first dual modulator of PPARα and STING, two targets tied to disparate pathologies in retinal diseases. Recognizing structural similarities between a reported STING inhibitor SN-013 and our previously described PPARα agonist A229, we designed BH400, which agonizes PPARα (EC50 = 1.2 μM) and inhibits STING (IC50 = 8.1 μM). BH400 demonstrates superior protection over single-target PPARα or STING modulation in microglial and photoreceptor cells. These findings provide compelling evidence for the potential benefit of polypharmacology in common retinal diseases through dual PPARα/STING modulation, motivating further studies.

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.

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.

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.

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.

Characterization of Vascular Morphology of Neovascular Age-Related Macular Degeneration by Indocyanine Green Angiography

Age-related macular degeneration (AMD) is a leading cause of blindness among older individuals, and its prevalence is rapidly increasing due to the aging population. Choroidal neovascularization (CNV) or wet AMD, which accounts for 10%-20% of all AMD cases, is responsible for an alarming 80%-90% of AMD-related blindness. Current anti-VEGF therapies show suboptimal responses in approximately 50% of patients. Resistance to anti-VEGF treatment in CNV patients is often associated with arteriolar CNV, while responders tend to have capillary CNV. While fluorescein angiography (FA) is commonly used to assess leakage patterns in wet AMD patients and animal models, it does not provide information about CNV vascular morphology (arteriolar CNV vs. capillary CNV). This protocol introduces the use of indocyanine green angiography (ICGA) to characterize lesion types in laser-induced CNV mouse models. This method is crucial for investigating the mechanisms and treatment strategies for anti-VEGF resistance in wet AMD. It is recommended to incorporate ICGA alongside FA for comprehensive assessment of both leakage and vascular features of CNV in mechanistic and therapeutic studies.

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.