Progress and Challenges of Anti-VEGF Agents and Their Sustained-Release Strategies for Retinal Angiogenesis

mTOR downregulation promotes anti-inflammatory responses via the CCL3-CCR5 axis in hypoxic retinopathy

Hypoxic retinopathies, including diabetic retinopathy, are major contributors to vision impairment, mainly due to accelerated angiogenesis and inflammation. Previously, we demonstrated that AAV2-shmTOR, effective across distinct species, holds therapeutic promise by modulating the activated mTOR pathway, yet its mechanisms for reducing inflammation remain largely unexplored. To investigate AAV2-shmTOR's impact on atypical inflammation in these conditions, we employed an in vivo model of oxygen-induced retinopathy and an in vitro model using rMC1 Müller cells. AAV2-shmTOR notably decreased mTOR expression in rMC1 cells under hypoxic conditions, as verified by co-staining for mTOR and glial fibrillary acidic protein (GFAP). It effectively interrupted the activation of mTOR signaling triggered by hypoxia. It diminished the secretion of CCL3 from rMC1 cells, consequently reducing microglial migration in response to conditioned media from AAV2-shmTOR-treated rMC1 cells. Notably, the virus lowered CCL3 expression in Müller cells and reduced the presence of CCR5-positive microglia in vivo, indicating its effectiveness in targeted inflammation management via the CCL3-CCR5 pathway. These findings thus highlight the potential of AAV2-shmTOR to exert anti-inflammatory effects by influencing the mTOR and subsequent CCL3-CCR5 pathways in hypoxic retinopathies, presenting a novel therapeutic approach for retinal diseases marked by hypoxia-driven inflammation.

Natural remedies proposed for the management of diabetic retinopathy (DR): diabetic complications

Diabetic retinopathy (DR) represents a significant and serious complication associated with diabetes mellitus (DM), often resulting in considerable visual impairment or even blindness. The intricate pathological processes underlying DR complicate the effectiveness of current treatment modalities. Studies have highlighted the potential of natural products in the treatment of DR via several beneficial effects including anti-inflammatory, antioxidant, anti-neovascular, and anti-apoptotic properties. Flavonoids, saponins, saccharides, and alkaloids exhibited various beneficial effects in DR in in vivo and in vitro studies. However, the clinical utilization of these natural compounds is hindered by issues such as inadequate specificity, low bioavailability, and potential toxicity. Therefore, there is a pressing need for rigorous clinical studies to confirm the efficacy of natural products in preventing or mitigating the progression of DR.

Seeing in the Future - a Perspective on Combining Light with Chemical Biology Approaches to Treat Retinal Pathologies

New concepts to treat eye diseases have emerged that elegantly combine unnatural light exposure with chemical biology approaches to achieve superior cellular specificity and, as a result, improvement of visual function. Historically, light exposure without further molecular eye treatment has offered limited success including photocoagulation to halt pathological blood vessel growth or low light exposure to stimulate retinal cell viability. To add cellular specificity to such treatments, researchers have introduced various biological or chemical light-sensing molecules and combined those with light exposure. (Pre-)clinical trials describe the use of optogenetics and channelrhodpsins, i. e. light-sensitive ion channels, in patient vision restoration. In the chemical arena, pharmacological agents, rendered light-sensitive by reversible modification with photosensitive protecting compounds ("caging"), have been applied to eyes of living mice to photo-release specific cellular activities. Among these were successful proof-of-principle experiments that were conducted to establish photo-sensitive gene therapies in the eye. For light-mediated treatment in combination with chemical biology, we wish to describe here the current frontiers of research in vision restoration with an eye on differences between biological and chemical light-sensing molecules, patient requirements, and future outlooks.

Treatment modalities and trends for hospitalized patients with neovascular glaucoma: A retrospective study of 10 years

To analyze the treatment modalities and trends for neovascular glaucoma (NVG) over the past 10 years, we conducted a retrospective analysis at Zhongshan Ophthalmic Center on 1331 NVG inpatients who received 1459 treatments for 1383 eyes between January 1, 2012, and December 31, 2021. Over time, we observed a progressive annual increase in both the number of patients and the volume of surgeries for NVG, with an annual percentage change (APC) of 10.23 % (95 % confidence interval [CI]: 5.5-15.2 %, P = 0.001) and 11.59 % (95 % CI: 6.6-16.9 %, P = 0.001), respectively. Drainage valve implantation (46.88 %), cyclodestructive procedures (22.55 %) and trabeculectomy (6.24 %) were the three most commonly selected treatment options. The frequency of drainage valve implantation (APC = 6.59 %, 95 % CI = 0.9-12.6 %, P = 0.028), cyclodestructive procedures (APC = 17.26 %, 95 % CI = 9.3-25.8 %, P = 0.001) and trabeculectomy (APC = 21.93 %, 95 % CI = 1.6-46.3 %, P = 0.036) increased. The proportion of drainage valve implantation gradually decreased (APC = -4.48 %, 95 % CI = -8.6 to -0.2 %, P = 0.042), while that of cyclodestructive procedures increased (APC = 5.08 %, 95 % CI = 0.6-9.8 %, P = 0.042), with no significant alteration observed in the proportion of trabeculectomy (APC = 9.26 %, 95 % CI = -8.8-30.9 %, P = 0.290). Over the course of the study, both the cases of NVG and the volume of related surgeries escalated year by year. Among the three most frequently employed procedures-drainage valve implantation, cyclodestructive procedures and trabeculectomy-annual frequency trends revealed an increase in drainage valve implantation alongside a decreasing proportion, while cyclodestructive procedures exhibited a rising trend in both frequency and proportion; simultaneously, trabeculectomy showed an increasing frequency without a significant change in its proportion.

A Novel Bispecific Anti-IL17/VEGF Fusion Trap Exhibits Potent and Long-Lasting Inhibitory Effects on the Development of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a severe eye disease in people aged 60 years and older. Although anti-VEGF therapies are effective in treating neovascular AMD (NvAMD) in the clinic, up to 60% of patients do not completely respond to the therapies. Recent studies have shown that blood-derived macrophages and their associated proinflammatory cytokines may play important roles in the development of persistent disease and resistance to anti-VEGF therapy. To address this issue, we constructed an antibody-based bispecific fusion protein that can simultaneously inhibit IL-17-induced inflammation and VEGF-mediated neovascularization. As a result, the bispecific fusion protein 17V05 effectively inhibited multiple proinflammatory cytokines and chemokines, as well as laser-induced choroidal neovascularization (CNV). More importantly, 17V05 also exhibited stronger and longer inhibitory effects than conbercept in vivo. Thus, we provide a novel and promising strategy for treating AMD patients who are not sensitive to anti-VEGF therapies.

Outcomes of Anti-VEGF Therapy in Eyes with Diabetic Macular Edema, Vein Occlusion-Related Macular Edema, and Neovascular Age-Related Macular Degeneration: A Systematic Review

Background

Anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionized the management of various ocular conditions, including diabetic macular edema (DME), retinal vein occlusion (RVO)-related macular edema (ME), and neovascular age-related macular degeneration (nAMD). However, there remains a need to systematically assess its effectiveness across these distinct conditions.

Methodology

A systematic review was conducted to identify studies evaluating the efficacy of anti-VEGF therapy in improving ocular outcomes in patients with DME, RVO-related ME, and nAMD. PubMed, Embase, and Cochrane Library databases were searched for relevant articles published up to 2024. Studies meeting the inclusion criteria were critically appraised, and data on the proportion of patients gaining ≥15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in best-corrected visual acuity (BCVA), mean change in BCVA (ETDRS letters), and reduction in central macular thickness (CMT) (μm) were extracted and synthesized.

Results

The systematic review identified 18 studies comprising randomized controlled trials, prospective studies, retrospective analyses, and observational studies. Anti-VEGF therapy demonstrated efficacy across all three conditions, with varying proportions of patients experiencing improvements in BCVA and reductions in CMT. Notably, the proportion of patients gaining ≥15 ETDRS letters ranged from 18.1% to 44.8% in DME, while mean changes in BCVA ranged from +4.2 letters to +21.4 letters in RVO-related ME and nAMD. Reductions in CMT ranged from 183.1 μm to 294 μm in DME and RVO-related ME.

Conclusion

Anti-VEGF therapy represents a cornerstone in the management of DME, RVO-related ME, and nAMD, with significant improvements observed in BCVA and reductions in CMT across diverse patient populations. While our findings support the effectiveness of anti-VEGF therapy in improving ocular outcomes, further research is warranted to compare its efficacy with alternative treatment modalities and to elucidate its long-term safety profile.

Characterization of RNA editing and gene therapy with a compact CRISPR-Cas13 in the retina

CRISPR-Cas13 nucleases are programmable RNA-targeting effectors that can silence gene expression in a transient manner. Recent iterations of Cas13 nucleases are compact for adeno-associated virus (AAV) delivery to achieve strong and persistent expression of various organs in a safe manner. Here, we report significant transcriptomic signatures of Cas13bt3 expression in retinal cells and show all-in-one AAV gene therapy with Cas13bt3 can effectively silence VEGFA mRNA in human retinal organoids and humanized VEGF transgenic mouse (trVEGF029, Kimba) models. Specifically, human embryonic stem cells (hESC)-derived retinal pigment epithelium cells show high expression of Cas13bt3 from virus delivery corresponding to a significant reduction of VEGFA mRNA. We further show that intravitreal delivery of Cas13bt3 by AAV2.7m8 can efficiently transduce mouse retinal cells for specific knockdown of human VEGFA in the Kimba mouse. Our results reveal important considerations for assessing Cas13 activity, and establish the Cas13bt3 RNA editing system as a potential anti-VEGF agent that can achieve significant control of VEGFA for the treatment of retinal neovascularization.

Molecular and Cellular Mechanisms Involved in the Pathophysiology of Retinal Vascular Disease-Interplay Between Inflammation and Oxidative Stress

Retinal vascular diseases encompass several retinal disorders, including diabetic retinopathy, retinopathy of prematurity, age-related macular degeneration, and retinal vascular occlusion; these disorders are classified as similar groups of disorders due to impaired retinal vascularization. The aim of this review is to address the main signaling pathways involved in the pathogenesis of retinal vascular diseases and to identify crucial molecules and the importance of their interactions. Vascular endothelial growth factor (VEGF) is recognized as a crucial and central molecule in abnormal neovascularization and a key phenomenon in retinal vascular occlusion; thus, anti-VEGF therapy is now the most successful form of treatment for these disorders. Interaction between angiopoietin 2 and the Tie2 receptor results in aberrant Tie2 signaling, resulting in loss of pericytes, neovascularization, and inflammation. Notch signaling and hypoxia-inducible factors in ischemic conditions induce pathological neovascularization and disruption of the blood-retina barrier. An increase in the pro-inflammatory cytokines-TNF-α, IL-1β, and IL-6-and activation of microglia create a persistent inflammatory milieu that promotes breakage of the blood-retinal barrier and neovascularization. Toll-like receptor signaling and nuclear factor-kappa B are important factors in the dysregulation of the immune response in retinal vascular diseases. Increased production of reactive oxygen species and oxidative damage follow inflammation and together create a vicious cycle because each factor amplifies the other. Understanding the complex interplay among various signaling pathways, signaling cascades, and molecules enables the development of new and more successful therapeutic options.

Müller Cells Harboring Exosomal lncRNA OGRU Modulate Microglia Polarization in Diabetic Retinopathy by Serving as miRNA Sponges

Diabetic retinopathy (DR) is one of the most common complications of diabetes worldwide and is associated with visual loss and blindness. However, effective treatments for both early- and late-stage DR remain lacking. A streptozotocin-induced diabetic mouse model and high glucose (HG)-treated Müller cell model were established. M1/M2 microglia polarization was assessed by immunofluorescence staining and flow cytometry. Expression of long noncoding RNA (lncRNA) OGRU, cytokines, and other key molecules was detected by quantitative RT-PCR or Western blot. ELISA was used to monitor cytokine secretion. Müller cell-derived exosomes were isolated and characterized by nanopartical tracking analysis, Western blot, and transmission electron microscopy, and exosome uptake assay was used to monitor the intercellular transport of exosomes. Associations among lncRNA-miRNA-mRNA networks were validated by RNA pulldown and RNA immunoprecipitation and dual luciferase assays. Increased M1 polarization but decreased M2 polarization of retinal microglia was observed in DR mice. HG-treated Müller cell-derived exosomes transported OGRU into microglia and promoted microglia polarization toward the M1 phenotype. Mechanistically, OGRU served as a competing endogenous RNA for miR-320-3p, miR-221-3p, and miR-574-5p to regulate aldose reductase (AR), PFKFB3, and glucose transporter 1 (GLUT1) expression in microglia, respectively. Loss of miR-320-3p/miR-221-3p/miR-574-5p or reinforced AR/PFKFB3/GLUT1 abrogated OGRU silencing-mediated microglia polarization in vitro. In vivo studies further showed that OGRU/miR-320-3p/AR, OGRU/miR-221-3p/PFKFB3, and OGRU/miR-574-5p/GLUT1 axes regulated microglia polarization in DR mice. Collectively, Müller cell-derived exosomal OGRU regulated microglia polarization in DR by modulating OGRU/miR-320-3p/AR, OGRU/miR-221-3p/PFKFB3, and OGRU/miR-574-5p/GLUT1 axes.

ARTICLE HIGHLIGHTS

Phase I DAVIO Trial: EYP-1901 Bioerodible, Sustained-Delivery Vorolanib Insert in Patients With Wet Age-Related Macular Degeneration

Purpose

To evaluate safety and tolerability of EYP-1901, an intravitreal insert containing vorolanib, a pan-VEGF receptor inhibitor packaged in a bioerodible delivery technology (Durasert E™) for sustained delivery, in patients with wet age-related macular degeneration (wAMD) previously treated with anti-VEGF therapy.

Design

Phase I, multicenter, prospective, open-label, dose-escalation trial.

Participants

Patients with wAMD and evidence of prior anti-VEGF therapy response.

Methods

Patients received a single intravitreal injection of EYP-1901.

Main Outcome Measures

The primary objective was to evaluate safety and tolerability of EYP-1901. Secondary objectives assessed biologic activity of EYP-1901 including best-corrected visual acuity (BCVA) and central subfield thickness (CST). Exploratory analyses included reduction in anti-VEGF treatment burden and supplemental injection-free rates.

Results

Seventeen patients enrolled in the 440 μg (3 patients), 1030 μg (1 patient), 2060 μg (8 patients), and 3090 μg (5 patients) dose cohorts. No dose-limiting toxicity, ocular serious adverse events (AEs), or systemic AEs related to EYP-1901 were observed. There was no evidence of ocular or systemic toxicity related to vorolanib or the delivery technology. Moderate ocular treatment-emergent AEs (TEAEs) included reduced visual acuity (2/17) and retinal exudates (3/17). One patient with reduced BCVA had 3 separate reductions of 17, 18, and 16 letters, and another had a single drop of 25 letters. One severe TEAE, neovascular AMD (i.e., worsening/progressive disease activity), was reported in 1 of 17 study eyes but deemed unrelated to treatment. Mean change from baseline in BCVA was -1.8 letters and -5.4 letters at 6 and 12 months. Mean change from baseline in CST was +1.7 μm and +2.4 μm at 6 and 12 months. Reduction in treatment burden was 74% and 71% at 6 and 12 months. Of 16 study eyes, 13, 8, and 5 were injection-free up to 3, 6, and 12 months.

Conclusion

In the DAVIO trial (ClinicalTrials.gov identifier, NCT04747197), EYP-1901 had a favorable safety profile and was well tolerated in previously treated eyes with wAMD. Measures of biologic activity remained relatively stable following a single EYP-1901 injection. These preliminary data support ongoing phase II and planned phase III trials to assess efficacy and safety.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

ω-3PUFAs Inhibit Hypoxia-Induced Retinal Neovascularization via Regulating Microglial Pyroptosis through METTL14-Mediated m6A Modification of IFNB1 mRNA

Retinal neovascular disease is the leading reason of vision impairment in all ages. Here, we figured out the function and mechanism of omega-3 polyunsaturated fatty acids (ω-3PUFAs) in hypoxia-induced retinal neovascularization by focusing on microglial pyroptosis. Microglia BV-2 cells were given ω-3PUFAs treatment and co-cultured with mouse retinal microvascular endothelial cells (MRMECs) under hypoxia. Tube formation assay, transwell assay and wound healing assay were utilized to monitor the MRMEC angiogenesis. Cell counting kit-8, western blot, lactate dehydrogenase assay, and enzyme-linked immunosorbent assay were used to assess pyroptosis of BV-2 cells. RNA sequencing and methylated RNA immunoprecipitation-polymerase chain reaction were utilized to identify the target gene of methyltransferase-like 14 (METTL14) and its N6-methyladenosine (m6A) level in BV-2 cells. BV-2 cells prominently enhanced MRMEC angiogenesis under hypoxia, but this effect was abolished after ω-3PUFAs treatment. ω-3PUFAs inhibited pyroptosis in hypoxia-induced BV-2 cells, and BV-2 cell pyroptosis boosted angiogenesis of MRMECs. Additionally, ω-3PUFAs markedly augment the expression of MELLL14 in BV-2 cells, and METTL14 knockdown promoted BV-2 cell pyroptosis and BV-2 cell-mediated angiogenesis in MEMECs. Mechanistically, interferon beta 1 (IFNB1) was a target of METTL14, and METTL14 silencing increased the mRNA expression and decreased the m6A modification of IFNB1 in BV-2 cells. Our results uncovered that ω-3PUFAs diminished hypoxia-induced retinal neovascularization through controlling microglial pyroptosis via METTL14-mediated m6A modification. This study offers a novel potential target for the treatment of retinal neovascular diseases.

The impact of removing the epiretinal membrane and inner limiting membrane for sustained subretinal fluid by macular neovascularization refractory to anti-VEGF therapy

Purpose

Anti-vascular endothelial growth factor (VEGF) therapy is the most prevalent intervention for exudative lesions secondary to neovascular age-related macular degeneration (nAMD) and other macular neovascularization (MNV). However, in some cases refractory to the latest anti-VEGF agents is associated with epiretinal membrane (ERM) or vitreomacular traction. We applied a vitrectomy to remove those pathologies which may be effective for reducing the exudation.

Observations

In this case report, we present 2 cases with sustained subretinal fluid and macular neovascularization secondary to nAMD or dome-shaped macula that poorly responded to anti-VEGF therapy. In both cases, removing thin ERM or vitreomacular traction with an inner limiting membrane peeling promptly resolved the subretinal fluid and no recurrence was observed thereafter.

Conclusions and importance

Vitrectomy could be an effective modality for anti-VEGF drug-resistant MNV cases with vitreomacular traction or ERM even in the anti-VEGF era.

Inhibition of hypoxia-inducible factors suppresses subretinal fibrosis

Age-related macular degeneration (AMD) is a common cause of vision loss. The aggressive form of AMD is associated with ocular neovascularization and subretinal fibrosis, representing a responsive outcome against neovascularization mediated by epithelial-mesenchymal transition of retinal pigment epithelium (RPE) cells. A failure of the current treatment (anti-vascular endothelial growth factor therapy) has also been attributed to the progression of subretinal fibrosis. Hypoxia-inducible factors (HIFs) increase gene expressions to promote fibrosis and neovascularization. HIFs act as a central pathway in the pathogenesis of AMD. HIF inhibitors may suppress ocular neovascularization. Nonetheless, further investigation is required to unravel the aspects of subretinal fibrosis. In this study, we used RPE-specific HIFs or von Hippel-Lindau (VHL, a regulator of HIFs) conditional knockout (cKO) mice, along with pharmacological HIF inhibitors, to demonstrate the suppression of subretinal fibrosis. Fibrosis was suppressed by treatments of HIF inhibitors, and similar suppressive effects were detected in RPE-specific Hif1a/Hif2a- and Hif1a-cKO mice. Promotive effects were observed in RPE-specific Vhl-cKO mice, where fibrosis-mediated pathologic processes were evident. Marine products' extracts and their component taurine suppressed fibrosis as HIF inhibitors. Our study shows critical roles of HIFs in the progression of fibrosis, linking them to the potential development of therapeutics for AMD.

A promising case of preclinical-clinical translation: β-adrenoceptor blockade from the oxygen-induced retinopathy model to retinopathy of prematurity

Although compartmentalization of the eye seems to promote its experimental manipulation, drug penetration to its posterior part is severely limited by hard barriers thus hindering drug development for eye diseases. In particular, angiogenesis-related retinal diseases share common mechanisms and are responsible for the majority of cases of blindness. Their prevalence is globally increasing mostly because of the increased incidence of systemic pathologies in the adult. Despite the number of preclinical findings demonstrating the efficacy of novel treatments, therapy of retinal neovascular diseases still remains confined to intravitreal anti-vascular endothelial growth factor treatments with some extension to anti-inflammatory therapy. In the mare magnum of preclinical findings aimed to develop novel avenues for future therapies, most compounds, despite their efficacy in experimental models, do not seem to meet the criteria for their therapeutic application. In particular, the groove between preclinical findings and their clinical application increases instead of decreasing and the attempt to bridging the gap between them creates intense frustration and a sense of defeat. In this complex scenario, we will discuss here the role that overactivation of the sympathetic system plays in retinal vessel proliferation in response to hypoxia using the oxygen-induced retinopathy (OIR) model. The potential application of the beta-adrenoceptor (β-AR) blockade with propranolol to the treatment of retinopathy of prematurity will be also discussed in light of preclinical findings in the OIR model and clinical trials using propranolol in preterm infants either per os or as eye drops.

Comparative efficacy of anti-vascular endothelial growth factor on diabetic macular edema diagnosed with different patterns of optical coherence tomography: A network meta-analysis

Intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections have emerged as the most common therapeutic approach for the management of diabetic macular edema (DME). Despite their proven superiority over other interventions, there is a paucity of data regarding the relative effectiveness of anti-VEGF agents in treating DME diagnosed with different patterns of optical coherence tomography (OCT). In this regard, we conducted a systematic review and comparative analysis of the therapeutic efficacy of intravitreal bevacizumab, ranibizumab, aflibercept, and conbercept in the management of DME with diffuse retinal thickening (DRT), cystoid macular edema (CME), and serous retinal detachment (SRD) patterns identified using OCT. Our study encompassed a comprehensive search of PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wan Fang Data from their inception until January 25, 2023. The network meta-analysis involved the inclusion of 1606 patients from 20 retrospective studies with a moderate risk of bias but no evidence of publication bias. The DRT group had the highest increase in best-corrected visual acuity (BCVA) with anti-VEGF, while the SRD group had the greatest reduction in Central Macular Thickness (CMT). Furthermore, conbercept, ranibizumab, and bevacizumab, respectively, showed the best treatment outcomes for patients with DRT, CME, and SRD in terms of improvement in BCVA. And, conbercept exhibited the highest reduction in CMT in the DRT, CME, and SRD groups. In conclusion, our study highlights the efficacy of anti-VEGF agents in the management of DME and provides valuable insights into the selection of anti-VEGF agents tailored to the individual needs of patients.

Exploring gellan gum-based hydrogels for regenerating human embryonic stem cells in age-related macular degeneration therapy: A literature review

Age-related macular degeneration (AMD) is a progressive ocular disease marked by the deterioration of retinal photoreceptor cells, leading to central vision decline, predominantly affecting the elderly population worldwide. Current treatment modalities, such as anti-VEGF agents, laser therapy, and photodynamic therapy, aim to manage the condition, with emerging strategies like stem cell replacement therapy showing promise. However, challenges like immune rejection and cell survival hinder the efficacy of stem cell interventions. Regenerative medicine faces obstacles in maximizing stem cell potential due to limitations in mimicking the dynamic cues of the extracellular matrix (ECM) crucial for guiding stem cell behaviour. Innovative biomaterials like gellan gum hydrogels offer tailored microenvironments conducive to enhancing stem cell culture efficacy and tissue regeneration. Gellan gum-based hydrogels, renowned for biocompatibility and customizable mechanical properties, provide crucial support for cell viability, differentiation, and controlled release of therapeutic factors, making them an ideal platform for culturing human embryonic stem cells (hESCs). These hydrogels mimic native tissue mechanics, promoting optimal hESC differentiation while minimizing immune responses and facilitating localized delivery. This review explores the potential of Gellan Gum-Based Hydrogels in regenerative AMD therapy, emphasizing their role in enhancing hESC regeneration and addressing current status, treatment limitations, and future directions.

Therapeutic Effects of Anti-Inflammatory and Anti-Oxidant Nutritional Supplementation in Retinal Ischemic Diseases

Appropriate nutrients are essential for cellular function. Dietary components can alter the risk of systemic metabolic diseases, including cardiovascular diseases, cancer, diabetes, and obesity, and can also affect retinal diseases, including age-related macular degeneration, diabetic retinopathy, and glaucoma. Dietary nutrients have been assessed for the prevention or treatment of retinal ischemic diseases and the diseases of aging. In this article, we review clinical and experimental evidence concerning the potential of some nutritional supplements to prevent or treat retinal ischemic diseases and provide further insights into the therapeutic effects of nutritional supplementation on retinopathies. We will review the roles of nutrients in preventing or protecting against retinal ischemic diseases.

Vascular Endothelial Growth Factor (VEGF) and Its Role in the Cardiovascular System

Cardiovascular diseases remain the leading cause of death worldwide, with ischemic heart disease (IHD) as the most common. Ischemia-induced angiogenesis is a process in which vascular endothelial growth factor (VEGF) plays a crucial role. To conduct research in the field of VEGF's association in cardiovascular diseases, it is vital to understand its role in the physiological and pathological processes in the heart. VEGF-based therapies have demonstrated a promising role in preclinical studies. However, their potential in human therapies is currently under discussion. Furthermore, VEGF is considered a potential biomarker for collateral circulation assessment and heart failure (HF) mortality. Additionally, as VEGF is involved in angiogenesis, there is a need to elucidate the impact of VEGF-targeted therapies in terms of cardiovascular side effects.

Aflibercept Off-Target Effects in Diabetic Macular Edema: An In Silico Modeling Approach

Intravitreal aflibercept injection (IAI) is a treatment for diabetic macular edema (DME), but its mechanism of action (MoA) has not been completely elucidated. Here, we aimed to explore IAI's MoA and its multi-target nature in DME pathophysiology with an in silico (computer simulation) disease model. We used the Therapeutic Performance Mapping System (Anaxomics Biotech property) to generate mathematical models based on the available scientific knowledge at the time of the study, describing the relationship between the modulation of vascular endothelial growth factor receptors (VEGFRs) by IAI and DME pathophysiological processes. We also undertook an enrichment analysis to explore the processes modulated by IAI, visualized the effectors' predicted protein activity, and specifically evaluated the role of VEGFR1 pathway inhibition on DME treatment. The models simulated the potential pathophysiology of DME and the likely IAI's MoA by inhibiting VEGFR1 and VEGFR2 signaling. The action of IAI through both signaling pathways modulated the identified pathophysiological processes associated with DME, with the strongest effects in angiogenesis, blood-retinal barrier alteration and permeability, and inflammation. VEGFR1 inhibition was essential to modulate inflammatory protein effectors. Given the role of VEGFR1 signaling on the modulation of inflammatory-related pathways, IAI may offer therapeutic advantages for DME through sustained VEGFR1 pathway inhibition.

Current Challenges in the Management of Vitreoretinal Conditions

In the dynamic realm of ophthalmology, the management of vitreoretinal conditions stands as a testament to both significant progress and ongoing challenges [...].

PFKFB3 in neovascular eye disease: unraveling mechanisms and exploring therapeutic strategies

BACKGROUND

Neovascular eye disease is characterized by pathological neovascularization, with clinical manifestations such as intraocular exudation, bleeding, and scar formation, ultimately leading to blindness in millions of individuals worldwide. Pathologic ocular angiogenesis often occurs in common fundus diseases including proliferative diabetic retinopathy (PDR), age-related macular degeneration (AMD), and retinopathy of prematurity (ROP). Anti-vascular endothelial growth factor (VEGF) targets the core pathology of ocular angiogenesis.

MAIN BODY

In recent years, therapies targeting metabolism to prevent angiogenesis have also rapidly developed, offering assistance to patients with a poor prognosis while receiving anti-VEGF therapy and reducing the side effects associated with long-term VEGF usage. Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a key enzyme in targeted metabolism, has been shown to have great potential, with antiangiogenic effects and multiple protective effects in the treatment of neovascular eye disease. In this review, we summarize the mechanisms of common types of neovascular eye diseases; discuss the protective effect and potential mechanism of targeting PFKFB3, including the related inhibitors of PFKFB3; and look forward to the future exploration directions and therapeutic prospects of PFKFB3 in neovascular eye disease.

CONCLUSION

Neovascular eye disease, the most common and severely debilitating retinal disease, is largely incurable, necessitating the exploration of new treatment methods. PFKFB3 has been shown to possess various potential protective mechanisms in treating neovascular eye disease. With the development of several drugs targeting PFKFB3 and their gradual entry into clinical research, targeting PFKFB3-mediated glycolysis has emerged as a promising therapeutic approach for the future of neovascular eye disease.

Barriers to care in neovascular age-related macular degeneration: Current understanding, developments, and future directions

Neovascular age-related macular degeneration is the advanced and irreversible stage of age-related macular degeneration, the leading cause of severe vision loss in older adults. While anti-vascular endothelial growth factor injections have been shown to preserve or improve vision quality in eyes with neovascular age-related macular degeneration, the treatment regimen can be demanding of patients and caregivers, leading to lower rates of adherence. Therefore, it is crucial that disparities and obstacles in neovascular age-related macular degeneration care are identified to improve access to treatment. Review of the current literature revealed 7 major categories of barriers: travel burden, psychological barriers, financial burden and socioeconomic status, treatment regimen, other comorbidities, provider-level barriers, and system-level barriers. We provide an overview of the major barriers to neovascular age-related macular degeneration care that have been reported, as well as gaps in research that need to be investigated further.

Safety and efficacy of ixoberogene soroparvovec in neovascular age-related macular degeneration in the United States (OPTIC): a prospective, two-year, multicentre phase 1 study

Background

Gene therapy, successfully used in rare, monogenetic disorders, may prove to be a durable management approach for common, polygenetic conditions, including neovascular age-related macular degeneration (nAMD). Repeated injections, oftentimes monthly, and possibly for decades, of vascular endothelial growth factor antagonists (anti-VEGF), is the standard for nAMD. We hypothesised that an in-office, intravitreal administration of ixoberogene soroparvovec (ixo-vec, formerly ADVM-022), a single-dose gene therapy encoding for the proven anti-VEGF protein, aflibercept, would transform retinal cells to continually produce aflibercept to minimise treatment burden in nAMD.

Methods

In this two-year, open-label, prospective, multicentre phase 1 study, patients with nAMD responding to anti-VEGF were assigned to four cohorts differing by ixo-vec dose (2 × 1011 vs 6 × 1011 vector genomes (vg/eye)) and prophylactic steroids (oral prednisone vs topical difluprednate). The primary outcome was the type, severity, and incidence of ocular and systemic adverse events (AEs); secondary endpoints included vision, central subfield thickness (CST), and the number of supplemental injections. This study was registered with ClinicalTrials.gov, NCT03748784.

Findings

Thirty patients with nAMD were enrolled between November 14, 2018 and June 30, 2020 at nine study sites in the United States. No systemic ixo-vec related AEs were noted. Across both dose groups the most common adverse event was anterior chamber cell, which was reported in 11 participants in the 6 × 1011 dose group and in 7 participants in the 2 × 1011 dose group; intraocular inflammation was responsive to topical corticosteroids, with no anterior chamber cells or vitreous cells observed in 2 × 1011 vg/eye patients at the end of the study. Vision and CST remained stable throughout two years with annualised anti-VEGF injections reduced by 80% (10.0 mean annualised anti-VEGF injections to 1.9) in 2 × 1011 vg/eye and 98% (9.8 mean annualised anti-VEGF injections to 0.2) in 6 × 1011 vg/eye cohorts.

Interpretation

Ixo-vec was generally well-tolerated, maintained vision, and improved anatomical outcomes in nAMD, with a substantial reduction in anti-VEGF injections. A single administration of an in-office gene therapy, with vectorised protein with an already established clinical benefit, has the potential to revolutionise the management of common ocular disorders requiring ongoing, frequent therapeutic interventions.

Funding

Adverum Biotechnologies.

Clinical Efficacy of Preoperative and Intraoperative Intravitreal Ranibizumab as Adjuvant Therapy of Ahmed Glaucoma Valve Implantation Combined with Vitrectomy in the Management of Neovascular Glaucoma with Diabetic Vitreous Hemorrhage

Neovascular glaucoma (NVG) secondary to proliferative diabetic retinopathy (PDR) is a devastating ocular disease with poor prognosis. Intravitreal ranibizumab injection (IVR) has been used as adjuvant therapy of surgical interventions preoperatively or intraoperatively. This study aimed to determine the efficacy and safety of combined IVR as adjuvant therapy in treating NVG with vitreous hemorrhage (VH) in PDR. A total of 39 NVG patients with VH (39 eyes) received IVR 3 to 5 days before surgery, and then they were assigned to either pars plana vitrectomy (PPV) + Ahmed glaucoma valve (AGV) implantation (Group 1, n = 22) or PPV + AGV implantation + intraoperative IVR (Group 2, n = 17). Patients were followed up for at least 9 months. Intraocular pressure (IOP), anti-glaucoma medications, best corrected visual acuity (BCVA), surgical success rates and postoperative complications were compared. Results showed that IOP decreased promptly after surgery and was notably maintained at a mid-term follow-up in both groups, and no significant differences were observed (all p > 0.05). Additional intraoperative IVR significantly reduced postoperative recurrent VH and iris neovascularization (p = 0.047, p = 0.025, respectively). There was no remarkable difference in postoperative anti-glaucoma medications, BCVA and complications between two groups (all p > 0.05). In conclusion, preoperative and intraoperative IVR as adjuvant therapy of AGV implantation combined with PPV could be a safe and effective treatment for NVG with VH in PDR. An additional intraoperative anti-VEGF injection could significantly reduce postoperative VH and iris neovascularization.

Retinoprotective compounds, current efficacy, and future prospective

Retinal dysfunction is the most common cause of vision loss in several retinal disorders. It has been estimated a great increase in these pathologies that are becoming more globally widespread and numerous over time, also supported by the life expectancy increment. Among different types of retinopathies, we can account some that share causes, symptoms, and treatment including diabetic retinopathy, age-related macular degeneration, glaucoma, and retinitis pigmentosa. Molecular changes, environmental factors, and genetic predisposition might be some of the main causes that drive retinal tissue to chronic inflammation and neurodegeneration in these retinopathies. The treatments available on the market contain compounds that efficiently ameliorate some of the important clinical features of these pathologies like stabilization of the intraocular pressure, reduction of eye inflammation, control of eye oxidative stress which are considered the major molecular mechanisms related to retinal dysfunction. Indeed, the most commonly used drugs are anti-inflammatories, such as corticosteroids, antioxidant, hypotonic molecules and natural neuroprotective compounds. Unfortunately, these drugs, which are fundamental to treating disease symptoms, are not capable to cure the pathologies and so they are not life-changing for patients. This review provided an overview of current treatments on the market, but more interestingly, wants to be a quick window on the new treatments that are now in clinical trials. Additionally, it has been here highlighted that the recent technical enhancement of the investigation methods to identify the various retinopathies causes might be used as a sort of "precise medicine" approach to tailor the identification of molecular pathways involved and potentially study a dedicated treatment for each patient. This approach includes the use of cutting-edge technologies like gene therapy and metabolomics.

Changing landscape of anti-angiogenic therapy: Novel approaches and clinical perspectives

Targeting angiogenesis has remained one of the important aspects in disease biology in general and cancer in particular. Currently (June 2023), over 593 clinical trials have been registered at ClinicalTrials.gov having inference of term 'angiogenesis'. A panel of 14 anti-angiogenic drugs have been approved by FDA for the treatment of variety of cancers and other human ailments. Although the anti-angiogenic therapy (AAT) has gained significant clinical attention as a promising approach in the treatment of various diseases, particularly cancer, however, sizable literature has accumulated in the recent past describing the aggressive nature of tumours after the drug holidays, evolving drug resistance and off-target toxicities. Nevertheless, the emergence of inscrutable compensatory or alternative angiogenic mechanisms is limiting the efficacy of anti-angiogenic drugs and focussing the therapeutic regime as a puzzle of 'Lernaean hydra'. This review offers an overview of recent updates on the efficacy of antiangiogenic therapy and the current clinical performance of aaRTK inhibitors. Additionally, it also explores the changing application landscape of AAT, focusing on its role in diabetic nephropathy, age-related macular degeneration and other neovascular ocular disorders. Combination therapy with antiangiogenic drugs and immune check point inhibitors (ICIs) has emerged as a potential strategy to enhance the therapeutic index of cancer immunotherapy. While clinical studies have demonstrated the clinical efficacy of this approach, they also highlight the complex and sometimes unpredictable adverse events associated with it. Normalizing tumour vasculature has been identified as a key factor in unlocking the full potential of ICIs, thereby providing hope for improved treatment outcomes. The future prospects and challenges of AAT have been described with special reference to integration of technological advances for enhancing its efficacy and applications beyond its discovery.

Combinative effects of β-elemene and propranolol on the proliferation, migration, and angiogenesis of hemangioma

Hemangioma (HA) is one of the most common benign vascular tumors among children. Propranolol is used as the first-line treatment for hemangioma and is a non-selective blocker of the β-adrenergic receptor. β-elemene is a compound extracted from Rhizoma zedoariae and has been approved for the treatment of tumors in clinical practice. However, the combinatorial effects of β-elemene and propranolol in the treatment of HA remains unclear. This study explored the combinative effects and mechanisms of β-elemene and propranolol using hemangioma-derived endothelial cells (HemECs). Cytotoxic assays showed that the combinatorial treatment of β-elemene and propranolol did not increase the cytotoxic effects of HemECs. Furthermore, functional analysis showed that the combinatorial treatment with β-elemene and propranolol significantly inhibited the proliferation, migration, and tube formation of the HemECs compared to the single treatment regimens. Mechanistic analysis showed that combinative treatment with β-elemene and propranolol synergistically down-regulated the hypoxia-inducible factor-1 alpha/vascular endothelial growth factor-A (HIF-1-α/VEGFA) signaling pathway. Additionally, in a xenograft tumor model, angiogenesis in the combinatorial treatment group was significantly lower than in the control, propranolol, and β-elemene treatment alone groups. Our results suggest that β-elemene combined with propranolol can significantly inhibit the proliferation, migration, and tube formation of HemECs via synergistically down-regulating the HIF-1-α/VEGFA signaling pathway without increasing any cytotoxic side effects.

Update on the Management of Diabetic Retinopathy: Anti-VEGF Agents for the Prevention of Complications and Progression of Nonproliferative and Proliferative Retinopathy

Diabetic retinopathy (DR) is a microvascular disease caused by poorly controlled blood glucose, and it is a leading cause of vision loss in people with diabetes. In this review we discuss the current management of DR with particular focus on the use of intraocular anti-vascular endothelial growth factor (anti-VEGF) agents. Intraocular anti-VEGF agents were first studied in the 1990s, and now several of these agents are either FDA approved or used off-label as first-line treatments for DR. Recent evidence shows that anti-VEGF agents can halt the progression of markers of DR severity, reduce the risk of DR worsening, and reduce the onset of new macular edema. These significant benefits have been demonstrated in patients with proliferative DR and the milder nonproliferative DR (NPDR). A wealth of evidence from recent trials and meta-analyses has detailed the intraoperative and postoperative benefits of adjunctive anti-VEGF therapy prior to pars plana vitrectomy (PPV) for proliferative DR with vitreous hemorrhage. In this review, we also discuss literature comparing various anti-VEGF injection regimens including monthly, quarterly, as-needed, and treat and extend protocols. Combination protocols with panretinal photocoagulation (PRP) or PPV are also discussed. Current evidence suggests that anti-VEGF therapies are effective therapy for NPDR and PDR and may also provide significant benefits when used adjunctively with other DR treatment modalities such as PRP or PPV.

Advanced Therapy Medicinal Products for Age-Related Macular Degeneration; Scaffold Fabrication and Delivery Methods

Retinal degenerative diseases such as age-related macular degeneration (AMD) represent a leading cause of blindness, resulting in permanent damage to retinal cells that are essential for maintaining normal vision. Around 12% of people over the age of 65 have some form of retinal degenerative disease. Whilst antibody-based drugs have revolutionised treatment of neovascular AMD, they are only effective at an early stage and cannot prevent eventual progression or allow recovery of previously lost vision. Hence, there is a clear unmet need to find innovative treatment strategies to develop a long-term cure. The replacement of damaged retinal cells is thought to be the best therapeutic strategy for the treatment of patients with retinal degeneration. Advanced therapy medicinal products (ATMPs) are a group of innovative and complex biological products including cell therapy medicinal products, gene therapy medicinal products, and tissue engineered products. Development of ATMPs for the treatment of retinal degeneration diseases has become a fast-growing field of research because it offers the potential to replace damaged retinal cells for long-term treatment of AMD. While gene therapy has shown encouraging results, its effectiveness for treatment of retinal disease may be hampered by the body's response and problems associated with inflammation in the eye. In this mini-review, we focus on describing ATMP approaches including cell- and gene-based therapies for treatment of AMD along with their applications. We also aim to provide a brief overview of biological substitutes, also known as scaffolds, that can be used for delivery of cells to the target tissue and describe biomechanical properties required for optimal delivery. We describe different fabrication methods for preparing cell-scaffolds and explain how the use of artificial intelligence (AI) can aid with the process. We predict that combining AI with 3D bioprinting for 3D cell-scaffold fabrication could potentially revolutionise retinal tissue engineering and open up new opportunities for developing innovative platforms to deliver therapeutic agents to the target tissues.

The β3 adrenoceptor in proliferative retinopathies: "Cinderella" steps out of its family shadow

In the retina, hypoxic condition leads to overgrowing leaky vessels resulting in altered metabolic supply that may cause impaired visual function. Hypoxia-inducible factor-1 (HIF-1) is a central regulator of the retinal response to hypoxia by activating the transcription of numerous target genes, including vascular endothelium growth factor, which acts as a major player in retinal angiogenesis. In the present review, oxygen urge by the retina and its oxygen sensing systems including HIF-1 are discussed in respect to the role of the beta-adrenergic receptors (β-ARs) and their pharmacologic manipulation in the vascular response to hypoxia. In the β-AR family, β1- and β2-AR have long been attracting attention because their pharmacology is intensely used for human health, while β3-AR, the third and last cloned receptor is no longer increasingly emerging as an attractive target for drug discovery. Here, β3-AR, a main character in several organs including the heart, the adipose tissue and the urinary bladder, but so far a supporting actor in the retina, has been thoroughly examined in respect to its function in retinal response to hypoxia. In particular, its oxygen dependence has been taken as a key indicator of β3-AR involvement in HIF-1-mediated responses to oxygen. Hence, the possibility of β3-AR transcription by HIF-1 has been discussed from early circumstantial evidence to the recent demonstration that β3-AR acts as a novel HIF-1 target gene by playing like a putative intermediary between oxygen levels and retinal vessel proliferation. Thus, targeting β3-AR may implement the therapeutic armamentarium against neovascular pathologies of the eye.

Identification of Novel Pathways Regulated by APE1/Ref-1 in Human Retinal Endothelial Cells

APE1/Ref-1 (apurinic/apyrimidinic endonuclease 1, APE1 or APEX1; redox factor-1, Ref-1) is a dual-functional enzyme with crucial roles in DNA repair, reduction/oxidation (redox) signaling, and RNA processing and metabolism. The redox function of Ref-1 regulates several transcription factors, such as NF-κB, STAT3, HIF-1α, and others, which have been implicated in multiple human diseases, including ocular angiogenesis, inflammation, and multiple cancers. To better understand how APE1 influences these disease processes, we investigated the effects of APEX1 knockdown (KD) on gene expression in human retinal endothelial cells. This abolishes both DNA repair and redox signaling functions, as well as RNA interactions. Using RNA-seq analysis, we identified the crucial signaling pathways affected following APEX1 KD, with subsequent validation by qRT-PCR. Gene expression data revealed that multiple genes involved in DNA base excision repair, other DNA repair pathways, purine or pyrimidine metabolism signaling, and histidine/one carbon metabolism pathways were downregulated by APEX1 KD. This is in contrast with the alteration of pathways by APEX1 KD in human cancer lines, such as pancreatic ductal adenocarcinoma, lung, HeLa, and malignant peripheral nerve sheath tumors. These results highlight the unique role of APE1/Ref-1 and the clinical therapeutic potential of targeting APE1 and pathways regulated by APE1 in the eye. These findings provide novel avenues for ocular neovascularization treatment.