Emerging therapeutic strategies for unmet need in neovascular age-related macular degeneration

Clinical and Socioeconomic Burden of Retinal Diseases: Can Biosimilars Add Value? A Narrative Review

Retinal diseases, such as neovascular age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion, pose a significant global burden on individuals, families, and healthcare systems. Intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy has become the standard treatment for retinal diseases, improving clinical outcomes, while delaying disease progression. Although effective, biologics are associated with high costs, which can lead to underutilisation and, consequently, suboptimal patient treatment outcomes, further contributing to healthcare costs. Additionally, the expansion in the elderly population is predicted to significantly increase costs and burden on healthcare systems due to retinal diseases, requiring effective strategies and the utilisation of emerging technologies that are crucial public health priorities for tackling global vision impairment. Recently, anti-VEGF biosimilars have been approved and are expected to provide a cost-effective alternative, while providing equivalent efficacy and comparable safety, immunogenicity, and pharmacokinetic profiles as the reference product. The entry of biosimilars holds the promise of meeting some of these unmet needs, giving physicians and patients access to sustainable treatments that can provide cost-effective therapy, enabling savings to be reinvested into healthcare facilities. This article aims to review the impact of retinal diseases on clinical, social, and financial aspects of patient care, emphasising the potential value of biosimilars in ophthalmology.

Advances in Regenerative Medicine, Cell Therapy, and 3D Bioprinting for Glaucoma and Retinal Diseases

Regenerative medicine, cell therapy, and 3D bioprinting represent promising advancements in addressing retinal and glaucomatous diseases. These conditions, including diabetic retinopathy (DR), age-related macular degeneration (AMD), inherited retinal degenerations (IRDs), and glaucomatous optic neuropathy, have complex pathophysiologies that involve neurodegeneration, oxidative stress, and vascular dysfunction. Despite significant progress in conventional therapies, including anti-VEGF injections, laser photocoagulation, and intraocular pressure (IOP)-lowering interventions, these approaches remain limited in reversing disease progression and restoring lost visual function.This chapter explores the potential of emerging regenerative therapies to fill these critical gaps. For retinal diseases, cell replacement strategies using human embryonic stem cells (hESCs), induced pluripotent stem cells (iPSCs), and mesenchymal stem cells (MSCs) have demonstrated encouraging outcomes in clinical trials, though challenges in delivery and long-term integration persist. Similarly, neuroprotective strategies and the use of retinal progenitor cells hold promise for preserving and restoring vision in degenerative retinal conditions. Advances in 3D bioprinting and retinal organoids further augment these efforts, offering innovative tools for disease modeling and therapy development.In glaucoma, regenerative approaches targeting trabecular meshwork (TM) dysfunction and retinal ganglion cell (RGC) loss are gaining traction. Stem cell-based therapies have shown potential in restoring TM functionality and providing neuroprotection, while innovative delivery systems and bioengineered platforms aim to enhance therapeutic efficacy and safety.This chapter provides an overview of the evolving landscape of regenerative therapies for retinal and glaucomatous diseases, highlighting current advancements, ongoing challenges, and future directions in the field. These approaches, while still emerging, hold the potential to transform the management of these complex ocular diseases.

Therapeutic potential of AAV2-shmTOR gene therapy in reducing retinal inflammation and preserving endothelial Integrity in age-related macular degeneration

Age-related macular degeneration (AMD) is a prevalent retinal disorder that leads to central vision loss, mainly due to chronic inflammation. Tumor necrosis factor-alpha (TNF-α) is a critical mediator of inflammatory responses within the retinal environment. This study has investigated TNF-α's influence on inflammatory cytokine production and endothelial barrier integrity in human microglial (HMC3) and endothelial (HUVEC) cells. We found that TNF-α significantly elevated the expression and secretion of interleukin-6 (IL-6) and interleukin-1β (IL-1β) in HMC3 cells and disrupted endothelial tight junctions in HUVECs, as evidenced by weakened ZO-1 staining and compromised barrier function. To mitigate these effects and further investigate the in vitro mechanism of actions in CRG-01's in vivo therapeutic efficacy of anti-inflammation, we employed AAV2-shmTOR, CRG-01, as the candidate for therapeutic vector targeting the mammalian target of the rapamycin (mTOR) pathway. TNF-α-induced IL-6, IL-1β, and NF-κB signaling in HMC3 cells were significantly reduced by AAV2-shmTOR treatment, which may present a promising avenue for the fight against AMD. It also effectively preserved endothelial tight junction integrity in TNF-α-treated HUVECs, providing reassurance about its effectiveness. Furthermore, the supernatant medium collected from AAV2-shmTOR-treated HMC3 cells decreased oxidative stress, protein oxidation, and cytotoxicity in ARPE retinal pigment epithelial cells. These results strongly suggested that CRG-01, the candidate therapeutic vector of AAV2-shmTOR, may have a therapeutic potential to treat AMD-related retinal inflammation.

MicroRNA-34a suppresses KLF2 to promote pathological angiogenesis through the CXCR4/CXCL12 pathway in age-related macular degeneration

Age-related macular degeneration (AMD), characterized by pathologic choroidal neovascularization (CNV), is a leading cause of vision loss in the elderly. Vascular endothelial growth factor A (VEGFa) antagonists can prevent acute vision loss, but high treatment burden and loss of efficacy with chronic therapy highlight the need to explore alternative mechanisms. Recently, microRNA-34a (miR-34a) has emerged as a key regulator in aging and age-related diseases, but its role in neovascular AMD is unclear. In an injury-induced murine CNV model, we discovered miR-34a promoted pathological angiogenesis, without altering expression of Vegfa or its receptor Kdr, the canonical regulators of CNV. Mechanistically, miR-34a directly targets and inhibits the transcription factor KLF2 thereby upregulating the pro-angiogenic factors CXCR4 and CXCL12. Finally, we show miR-34a exacerbates CNV in aged mice and is expressed in CNV lesions excised from wet AMD patients. These findings establish a causal link between the age-related miR-34a and neovascularization in AMD.

Teaser

Identification of a molecular mechanism involved in the pathogenesis of a prevalent and debilitating age-related ocular disease.

Utilization of Nanoparticles for Treating Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a predominant cause of vision loss, posing significant challenges in its management despite advancements such as anti-vascular endothelial growth factor (anti-VEGF) therapy. Nanomedicine, with its novel properties and capabilities, offers promising potential to transform the treatment paradigm for AMD. This review reports the significant advancements in the use of diverse nanoparticles (NPs) for AMD in vitro, in vivo, and ex vivo, including liposomes, lipid nanoparticles, nanoceria, nanofibers, magnetic nanoparticles, quantum dots, dendrimers, and polymer nanoparticles delivered in forms such as gels, eye drops, intravitreally, or intravenously. Drug delivery was the most common use of NPs for AMD, followed by photodynamic therapy dose enhancement, antioxidant function for nanoceria, biomimetic activity, and immune modulation. Innovative approaches arising included nanotechnology-based photodynamic therapy and light-responsive nanoparticles for controlled drug release, as well as gene therapy transfer. Nanomedicine offers a transformative approach to the treatment and management of AMD, with diverse applications. The integration of nanotechnology in AMD management not only provides innovative solutions to overcome current therapeutic limitations but also shows potential in enhancing outcomes and patient quality of life.

DNA Methyltransferase Expression (DNMT1, DNMT3a, and DNMT3b) as a Potential Biomarker in Age-Related Macular Degeneration

Background/Objectives: Age-related macular degeneration (AMD) is a global cause of vision loss, with limited therapeutic options highlighting the need for effective biomarkers. This study aimed to characterize plasma DNA methyltransferase expression (DNMT1, DNMT3A, and DNMT3B) in AMD patients and explore divergent expression patterns across different stages of AMD. Methods: Thirty-eight AMD patients were prospectively enrolled and stratified by disease severity: eAMD, iAMD, nAMD, and aAMD. Comprehensive ophthalmological assessments were performed, including best-corrected visual acuity, digital color fundus photographs, and Spectral Domain Optical Coherence Tomography. Peripheral blood samples were collected for RNA extraction and qRT-PCR to access epigenetic effectors' transcriptional expression, namely DNMT1, DNMT3A, and DNMT3B genes. The collected data were analyzed using IBM SPSS 29. Results:DNMT1 expression was significantly downregulated in late AMD (-0.186 ± 0.341) compared to early/intermediate AMD (0.026 ± 0.246). Within late AMD, aAMD exhibited a marked downregulation of DNMT1 (-0.375 ± 0.047) compared to nAMD (0.129 ± 0.392). DNMT3A and DNMT3B showed similar divergent expression patterns, correlating with disease stage. Conclusions: This study identified stage-specific transcriptional differences in DNMT expression, emphasizing its potential as a biomarker for AMD progression and a target for future research into personalized therapeutic strategies.

Tyrosine Kinase Inhibitors: The Next Chapter in Reducing Treatment Burden for Exudative Retinal Diseases?

Tyrosine kinase inhibitors (TKIs) serve to inhibit the phosphorylation cascade that usually leads to abnormal processes such as vascular leakage and tumorigenesis. Within retinal diseases specifically, dysregulation of the vascular endothelial growth factor receptor tyrosine kinases can lead to age-related macular degeneration and diabetic macular edema. These diseases have a growing prevalence and are leading causes of vision loss. The current standard of care requires repeated administration of anti-vascular endothelial growth factor injections, which poses a significant burden on patients. Novel TKIs provide an opportunity to reduce injection frequency by targeting a broader range of molecules involved in angiogenesis and exudation. This review will cover TKIs in development and how their use of different technologies and targets may enhance visual and anatomic outcomes for patients with exudative retinal disease.

Efficacy, durability and safety of faricimab for patients with neovascular age-related macular degeneration: 48-week results from the phase 3 LUCERNE China subpopulation

PURPOSE

To evaluate the efficacy, durability and safety of intravitreal faricimab versus aflibercept over 48 weeks in patients with neovascular age-related macular degeneration (nAMD) from the LUCERNE China subpopulation.

DESIGN

LUCERNE (NCT03823300) was a phase 3 global, double-masked, active comparator-controlled trial. The China subpopulation comprised patients from mainland China, Taiwan and Hong Kong.

METHODS

Treatment-naïve patients aged ≥50 years with nAMD were randomized 1:1 to receive faricimab 6.0 mg up to every 16 weeks (Q16W) based on prespecified disease criteria after four initial Q4W doses or aflibercept 2.0 mg Q8W after three initial Q4W doses. The primary endpoint was mean change from baseline in best-corrected visual acuity (BCVA) averaged over weeks 40 to 48. Anatomical, durability and safety outcomes were also evaluated.

RESULTS

The China subpopulation comprised 119 patients (faricimab: n = 59, aflibercept: n = 60). At weeks 40 to 48, adjusted mean (95% confidence interval [CI]) BCVA letter gains from baseline were +9.7 (7.4 to 12.0) and +9.8 (7.5 to 12.1) with faricimab and aflibercept, respectively. Central subfield thickness was reduced from baseline by weeks 40 to 48 in both arms, with an adjusted mean (95% CI) change of -145.4 µm (-156.2 to -134.6) and -156.5 µm (-167.3 to -145.7) for faricimab and aflibercept, respectively. By week 48, 87.3% of the patients were on extended ≥Q12W faricimab dosing. Faricimab was well tolerated with no new safety signals.

CONCLUSIONS

Faricimab up to Q16W showed durable efficacy in the LUCERNE China subpopulation, consistent with global findings. Faricimab may reduce treatment burden for patients with nAMD in China, without compromising efficacy.

Sphingomonas arvum sp. nov.: A promising microbial chassis for high-yield and sustainable zeaxanthin biomanufacturing

The yield of natural products from plants is currently insufficient and cannot be considered a sustainable and secure source of supply, especially given the challenges posed by global climate change. Therefore, a biofoundry that can quickly and accurately produce desired materials from microorganisms based on synthetic biology is urgently needed. Moreover, it is important to find new microbial and genetic chassis to meet the rapidly growing global market for high-value-added zeaxanthin. In this study, we aimed to identify the zeaxanthin biosynthetic gene cluster, crtZ-crtB-crtI-crtY, and confirm zeaxanthin production (11,330 μg g-1 dry biomass weight) through genome mining and liquid chromatography/mass spectrometry profiling using the novel zeaxanthin-producing bacteria Sphingomonas sp. strain BN140010T isolated from the subsurface soil of arable land. We report the highest yield among zeaxanthin-producing Sphingomonas strains to date. Moreover, we determined the taxonomic position of BN140010T using a polyphasic approach based on phylogenetic, physiological and chemotaxonomic characteristics, and we proposed Sphingomonas arvum strain BN140010T as a novel strain. Our results provide a zeaxanthin-producing chassis and diverse genetic tools for microbiological zeaxanthin production. Therefore, this research advances our progress towards the goal of lowering the unit cost of zeaxanthin production, making it more accessible for industrial applications.

Prognostic value of macular neovascularisation characteristics for photoreceptor integrity in nAMD: a prospective observational study

PURPOSE

To explore the relationship between characteristics of macular neovascularisation (MNV) and photoreceptor integrity in patients with neovascular age-related macular degeneration (nAMD).

METHODS

This prospective study enrolled treatment-naïve nAMD eyes and conducted a 3-month follow-up. 16 quantitative MNV features were evaluated using optical coherence tomography angiography, and the impaired areas of ellipsoid zone (EZ), external limiting membrane (ELM) and outer nuclear layer (ONL) were obtained using optical coherence tomography. Correlation and regression analyses assessed the relationships between MNV features and photoreceptor integrity.

RESULTS

110 nAMD eyes from 110 patients (73.64% men) were included. Baseline MNV characteristics, including MNV perimeter, maxFeret, minFeret, vessel area, total vessel length, total number of junctions and endpoints, and mean E lacunarity, were positively correlated with photoreceptor damage areas (r ranging from 0.227 to 0.558, p<0.05 for all). Meanwhile, vessel density negatively correlated with photoreceptor damage (r=-0.468 for EZ, -0.394 for ELM and -0.538 for ONL, all p<0.05). After the loading phase, the EZ prognosis was independently associated with baseline MNV minFeret (Std β=0.362, p=0.011) and mean E lacunarity (Std β=0.130, p=0.041). The prognosis for ELM was independently linked to baseline MNV minFeret (Std β=0.373, p=0.014), while no significant factors were found to influence ONL prognosis (p>0.05 for all).

CONCLUSION

A strong correlation was observed between MNV features and photoreceptor integrity, with larger and more complex vascular networks associated with greater photoreceptor damage.

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.

Role of inflammation in diabetic macular edema and neovascular age-related macular degeneration

Diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD) are multifactorial disorders that affect the macula and cause significant vision loss. Although inflammation and neoangiogenesis are hallmarks of DME and nAMD, respectively, they share some biochemical mediators. While inflammation is a trigger for the processes that lead to the development of DME, in nAMD inflammation seems to be the consequence of retinal pigment epithelium and Bruch membrane alterations. These pathophysiologic differences may be the key issue that justifies the difference in treatment strategies. Vascular endothelial growth factor inhibitors have changed the treatment of both diseases, however, many patients with DME fail to achieve the established therapeutic goals. From a clinical perspective, targeting inflammatory pathways with intravitreal corticosteroids has been proven to be effective in patients with DME. On the contrary, the clinical relevance of addressing inflammation in patients with nAMD has not been proven yet. We explore the role and implication of inflammation in the development of nAMD and DME and its therapeutical relevance.

Dual pathway inhibition with faricimab for previously treated neovascular age-related macular degeneration and diabetic macular oedema: guidance from a UK panel of retina specialists

BACKGROUND/OBJECTIVES

Some eyes with neovascular age-related macular degeneration (nAMD) and centre-involving diabetic macular oedema (DMO) fail to respond sufficiently or lose response over time to standard of care intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy. This paper explores clinical scenarios for switching to dual action angiopoietin-2 (Ang-2)/VEGF-A inhibitor faricimab (Vabysmo, Roche Products Limited) in previously anti-VEGF-treated patients.

METHODS

A national steering group meeting of UK retina specialists was held in London on 27 October 2023. Clinician practice and experience were reviewed together with pivotal clinical trial data and early findings from real-world settings. Roche Products Limited facilitated and funded the meeting.

RESULTS

While there is no standardised protocol for identifying suboptimal response, the authors review relevant clinical biomarkers of disease activity used in routine clinical practice to determine patient response and guide treatment decisions. Common reasons identified for considering a change of treatment were lack of efficacy demonstrated by suboptimal anatomic or visual improvement and insufficient durability of response. The panel outline strategies for switching to faricimab among eligible patients with a prior anti-VEGF treatment history, with initial monthly loading doses or maintaining the previous treatment interval before attempting to extend, that may be integrated into current treat-and-extend (T&E) clinical pathways for treating patients with nAMD and DMO. General considerations for switching between treatments are also reviewed.

CONCLUSION

Clinicians may consider a treatment switch to faricimab in nAMD and DMO patients who have suboptimal disease control or insufficient durability of response on initial anti-VEGF therapy.

Age-Related Macular Degeneration (AMD): Pathophysiology, Drug Targeting Approaches, and Recent Developments in Nanotherapeutics

The most prevalent reason for vision impairment in aging inhabitants is age-related macular degeneration (AMD), a posterior ocular disease with a poor understanding of the anatomic, genetic, and pathophysiological progression of the disease. Recently, new insights exploring the role of atrophic changes in the retinal pigment epithelium, extracellular drusen deposits, lysosomal lipofuscin, and various genes have been investigated in the progression of AMD. Hence, this review explores the incidence and risk factors for AMD, such as oxidative stress, inflammation, the complement system, and the involvement of bioactive lipids and their role in angiogenesis. In addition to intravitreal anti-vascular endothelial growth factor (VEGF) therapy and other therapeutic interventions such as oral kinase inhibitors, photodynamic, gene, and antioxidant therapy, as well as their benefits and drawbacks as AMD treatment options, strategic drug delivery methods, including drug delivery routes with a focus on intravitreal pharmacokinetics, are investigated. Further, the recent advancements in nanoformulations such as polymeric and lipid nanocarriers, liposomes, etc., intended for ocular drug delivery with pros and cons are too summarized. Therefore, the purpose of this review is to give new researchers an understanding of AMD pathophysiology, with an emphasis on angiogenesis, inflammation, the function of bioactive lipids, and therapy options. Additionally, drug delivery options that focus on the development of drug delivery system(s) via several routes of delivery can aid in the advancement of therapeutic choices.

Two-year Outcomes of Intravitreal Aflibercept Injection for Neovascular Age-related Macular Degeneration with "Observe before Treat-and-Extend" Method

PURPOSE

To evaluate 2-year outcomes of intravitreal aflibercept injection for neovascular age-related macular degeneration (nAMD) treated with "observe before treat-and-extend (O-TAE)" strategy in the real-world setting.

METHODS

This retrospective study included treatment-naive nAMD patients treated with aflibercept using O-TAE regimen and followed up for more than 2 years. Patients were observed bimonthly to check recurrence after three monthly loading injections. In case of recurrence, treatment was resumed using the TAE regimen starting from the fourth injection. In case of nonrecurrence, observation was continued. Best-corrected visual acuity (BCVA), central macular thickness (CMT), number of injections, TAE intervals, and proportion of recurrence after dry-up following three loadings were analyzed.

RESULTS

A total of 38 eyes of 34 patients were included. Follow-up period was 37.0 ± 11.0 months. BCVA by logarithm of minimal angle of resolution improved from 0.33 ± 0.29 at baseline to 0.24 ± 0.23 in the first year (p = 0.010) and 0.25 ± 0.22 in the second year (p = 0.054). CMT decreased significantly from 357.43 ± 74.53 μm at baseline to 269.62 ± 48.12 μm in the first year (p < 0.001) and 279.14 ± 54.64 μm in the second year (p < 0.001). Number of injections were 5.11 ± 1.69 in the first year and 3.84 ± 2.39 in the second year. The percentage of eyes with a TAE interval of ≥12 weeks was 37.0% in the first year and 34.4% in the second year. Of the 36 eyes that dried up after three loadings, 28 eyes (77.8%) recurred, and the average period of recurrence was 6.5 months. The remaining eight eyes (22.2%) had no recurrence during the mean follow-up period of 29.7 months.

CONCLUSIONS

This study showed that the newly suggested O-TAE strategy can reduce the treatment burden significantly reducing the number of injections while improving BCVA and CMT in the first and second year.

Multifocal Electroretinography Changes after UBX1325 (Foselutoclax) Treatment in Neovascular Age-Related Macular Degeneration

Background/Objectives: The objective of this study was to determine the treatment effect of foselutoclax in neovascular age-related macular degeneration (AMD) by multifocal electroretinography (mfERG) and evaluate mfERG as a potential clinical endpoint in AMD studies. Methods: A total of five subjects were included in the study who had active choroidal neovascularization and a history of at least two anti-vascular endothelial growth factor (VEGF) injections in the last 6 months. Subjects received a 50 µL intravitreal injection of foselutoclax at the baseline visit and Weeks 4, 24, and 28 of the study period. Results: After foselutoclax treatment, the largest improvement in the mfERG N1-P1 response density occurred at Week 8 as three of five subjects achieved a ≥20% gain. In addition, three of five subjects demonstrated a BCVA improvement of ≥5 ETDRS letters over baseline at Weeks 4, 8, and 24. The mean change in BCVA demonstrated statistical significance in Weeks 4 and 8, showing increases of 5 (p = 0.02) and 6.2 (p = 0.02) letters, respectively. Conclusions: Foselutoclax treatment was shown to have the potential to recover outer retinal function as determined by mfERG and BCVA at approximately Week 8 of treatment.

Off-Label Use of Bevacizumab in Patients Diagnosed with Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of vision loss in elderly people. Current pharmacological treatment in vascular AMD includes anti-VEGF agents, such as ranibizumab and aflibercept. Additionally, the off-label use of bevacizumab has been shown to be effective and has a lower cost, making it an interesting pharmacological approach; however, there is no consensus about its use. Therefore, this systematic review and meta-analysis aims to evaluate the efficacy, safety, and efficiency of bevacizumab in AMD patients.

METHODS

This review only focused on randomized controlled clinical trials published in 2010 in the MEDLINE database that compared the effect of bevacizumab with ranibizumab. The risk of bias in each included study was assessed using the CASP Randomised Clinical Trials checklist.

RESULTS

Twelve studies were included for qualitative synthesis, and nine of them were considered for meta-analysis. Bevacizumab-treated patients showed a significantly reduced neovascularization in a longer spectrum of time; however, they had a higher incidence of endophthalmitis than those treated with ranibizumab. Regarding efficiency, the mean number of administrations was reduced in the treatment with bevacizumab in comparison to ranibizumab.

CONCLUSIONS

Clinical evidence demonstrates that bevacizumab has efficacy and safety profiles comparable with ranibizumab; however, it is relatively more efficient.

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.

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.

Factors Involved in Anti-VEGF Treatment Decisions for Neovascular Age-Related Macular Degeneration: Insights from Real-World Clinical Practice

Background

Anti-vascular endothelial growth factor (anti-VEGF) agents are widely prescribed for the treatment of neovascular age-related macular degeneration (nAMD). Although studies have investigated patient choice of anti-VEGF agent, little is known regarding factors that influence physician preference of anti-VEGF agent for their patients.

Objective

To describe physician rationale and challenges in prescribing anti-VEGF treatments for patients with nAMD.

Methods

Data were drawn from the Adelphi Real World nAMD Disease Specific Programme™, a cross-sectional survey with retrospective data capture of physicians and their patients with nAMD in the United States between October 2021 and May 2022. Physicians (n = 56) reported data for up to 13 consecutively consulting patients (n = 451), including current anti-VEGF treatments used, factors affecting physicians' choice of anti-VEGF agent and treatment strategy, and restrictions on specific agents.

Results

Most physicians prefer employing a "treat-and-extend" treatment strategy, over "fixed interval" or "pro re nata" strategies. However, in routine clinical practice, "treat-and-extend" was reported for less than half of nAMD-diagnosed eyes. Top factors influencing physician choice of anti-VEGF agent and treatment strategy included maximizing clinical benefit (eg visual acuity gains and fluid control), patient convenience, and reducing out-of-pocket costs. However, physicians also reported facing substantial roadblocks in prescribing their choice of anti-VEGF agent, including restrictions on approved agents and gaps in insurance coverage. Persistent fluid was the most common physician-selected reason for switching a patient away from an anti-VEGF agent.

Conclusion

Physicians face barriers to prescribing their preferred anti-VEGF agents in real-world healthcare settings. Overcoming these challenges may improve treatment outcomes for patients with nAMD.

Anti-vascular endothelial growth factor biosimilars for neovascular age-related macular degeneration

RATIONALE

Neovascular age-related macular degeneration (AMD) is a progressive eye disease characterized by choroidal neovascularization (CNV) and is a leading cause of vision loss and disability worldwide. Although intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is an effective treatment option that helps to prevent vision loss or to improve visual acuity in people with neovascular AMD, treatment imposes a significant financial burden on patients and healthcare systems. A biosimilar is a biological product that has been developed to be nearly identical to a previously approved biological product. The use of biosimilars may help reduce costs and so may increase patient access to effective biologic medicines with similar levels of safety to the drugs on which they are based.

OBJECTIVES

To assess the benefits and harms of anti-VEGF biosimilar agents compared with their corresponding anti-VEGF agents (i.e. the reference products) that have obtained regulatory approval for intravitreal injections in people with neovascular AMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases, and two trials registries together with reference checking and contact with study authors to identify studies that are included in the review. The latest search date was 2 June 2023.

ELIGIBILITY CRITERIA

We included randomized controlled trials (RCTs) that compared approved anti-VEGF biosimilars with their reference products for treating the eyes of adult participants (≥ 50 years) who had an active primary or recurrent choroidal neovascularization lesion secondary to neovascular AMD.

OUTCOMES

Our outcomes were: best-corrected visual acuity (BCVA), central subfield thickness (CST), vision-related quality of life, serious ocular and non-ocular adverse events (AE), treatment-emergent adverse events (TEAEs), anti-drug antibodies (ADAs), and serum concentrations of biosimilars and reference drugs.

RISK OF BIAS

We assessed the risk of bias (RoB) for seven outcomes reported in a summary of findings table by using the Cochrane RoB 2 tool.

SYNTHESIS METHODS

We synthesized results for each outcome using meta-analysis, where possible, by calculating risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI) for dichotomous outcomes and continuous outcomes, respectively. Where this was not possible due to the nature of the data, we summarized the results narratively. We used GRADE to assess the certainty of evidence for prespecified outcomes.

INCLUDED STUDIES

We included nine parallel-group multi-center RCTs that enrolled a total of 3814 participants (3814 participating eyes), with sample sizes that ranged from 160 to 705 participants per study. The mean age of the participants in these studies ranged from 67 to 76 years, and the proportion of women ranged from 26.5% to 58.7%. Ranibizumab (Lucentis) was the reference product in seven studies, and aflibercept (Eyelea) was the reference product in two others. All the included studies had been supported by industry. The follow-up periods ranged from 12 to 52 weeks (median 48 weeks). Five studies (56%) were conducted in multi-country settings across Europe, North America and Asia, two studies in India, and one each in Japan and the Republic of Korea. We judged all the included studies to have met high methodological standards.

SYNTHESIS OF RESULTS

With regard to efficacy, our meta-analyses demonstrated that anti-VEGF biosimilars for neovascular AMD resulted in little to no difference compared with the reference products for BCVA change at 8 to 12 weeks (MD -0.55 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, 95% CI -1.17 to 0.07; 8 studies, 3603 participants; high-certainty evidence) and the proportion of participants who lost fewer than 15 letters in BCVA at 24 to 48 weeks (RR 0.99, 95% CI 0.98 to 1.01; 7 studies, 2658 participants; moderate-certainty evidence). Almost all participants (96.6% in the biosimilar group and 97.0% in the reference product group) lost fewer than 15 letters in BCVA. The evidence from two studies suggested that there was no evidence of difference between biosimilars and reference products in vision-related quality of life measured by the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) summary scores at 24 to 48 weeks (MD 0.82, 95% CI -0.70 to 2.35; 2 studies, 894 participants; moderate-certainty evidence). With regard to the safety profile, meta-analyses also revealed little to no difference between anti-VEGF biosimilars and the reference products for the proportion of participants who experienced serious ocular AEs (RR 1.24, 95% CI 0.68 to 2.26; 7 studies, 3292 participants; moderate-certainty evidence), and for TEAEs leading to investigational product discontinuation or death (RR 0.96, 95% CI 0.63 to 1.46; 8 studies, 3497 participants; moderate-certainty evidence). Overall, 1.4% of participants in the biosimilar group and 1.2% in the reference product group experienced serious ocular adverse events. The most frequently documented serious ocular AEs were retinal hemorrhage and endophthalmitis. Although the evidence is of low certainty due to imprecision, meta-analysis suggested that anti-VEGF biosimilars led to no difference compared with the reference products for cumulative incidence of ADAs (RR 0.84, 95% CI 0.58 to 1.22; 8 studies, 3066 participants; low-certainty evidence) or mean maximum serum concentrations (MD 0.42 ng/mL, 95% CI -0.22 to 1.05; subgroup of 3 studies, 100 participants; low-certainty evidence). We judged the overall risk of bias to be low for all studies.

AUTHORS' CONCLUSIONS

In our review, low to high certainty evidence suggests that there is little to no difference, to date, between the anti-VEGF biosimilars approved for treating neovascular AMD and their reference products in terms of benefits and harms. While anti-VEGF biosimilars may be a viable alternative to reference products, current evidence for their use is based on a limited number of studies - particularly for comparison with aflibercept - with sparse long-term safety data, and infrequent assessment of quality of life outcomes. Our effect estimates and conclusions may be modified once findings have been reported from studies that are currently ongoing, and studies of biosimilar agents that are currently in development.

FUNDING

Cochrane Eyes and Vision US Project is supported by grant UG1EY020522, National Eye Institute, National Institutes of Health. Takeshi Hasegawa and Hisashi Noma were supported by Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (Grant numbers: 22H03554, 19K03092, 24K06239).

REGISTRATION

Protocol available via doi.org/10.1002/14651858.CD015804.

Harnessing the potential of mesenchymal stem cells-derived exosomes in degenerative diseases

Mesenchymal stem cells (MSCs) have gained attention as a promising therapeutic approach in both preclinical and clinical osteoarthritis (OA) settings. Various joint cell types, such as chondrocytes, synovial fibroblasts, osteoblasts, and tenocytes, can produce and release extracellular vesicles (EVs), which subsequently influence the biological activities of recipient cells. Recently, extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have shown the potential to modulate various physiological and pathological processes through the modulation of cellular differentiation, immune responses, and tissue repair. This review explores the roles and therapeutic potential of MSC-EVs in OA and rheumatoid arthritis, cardiovascular disease, age-related macular degeneration, Alzheimer's disease, and other degenerative diseases. Notably, we provide a comprehensive summary of exosome biogenesis, microRNA composition, mechanisms of intercellular transfer, and their evolving role in the highlight of exosome-based treatments in both preclinical and clinical avenues.

Lemon Peel Water Extract: A Novel Material for Retinal Health, Protecting Retinal Pigment Epithelial Cells against Dynamin-Related Protein 1-Mediated Mitochondrial Fission by Blocking ROS-Stimulated Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Pathway

Previous studies showed that NaIO3 can induce oxidative stress-mediated retinal pigment epithelium (RPE) damage to simulate age-related macular degeneration (AMD). Lemon peel is rich in antioxidants and components that can penetrate the blood-retinal barrier, but their role in retinal oxidative damage remains unexplored. Here, we explore the protection of lemon peel ultrasonic-assisted water extract (LUWE), containing large amounts of flavonoids and polyphenols, against NaIO3-induced retinal degeneration. We initially demonstrated that LUWE, orally administered, prevented retinal distortion and thinning on the inner and outer nuclei layers, downregulating cleaved caspase-3 protein expression in RPE cells in NaIO3-induced mice. The effect of LUWE was achieved through the suppression of apoptosis and the associated proteins, such as cleaved PARP and cleaved caspase-3, as suggested by NaIO3-induced ARPE-19 cell models. This is because LUWE reduced reactive oxygen species-mediated mitochondrial fission via regulating p-Drp-1 and Fis1 expression. We further confirmed that LUWE suppresses the expression of p-MEK-1/2 and p-ERK-1/2 in NaIO3-induced ARPE-19 cells, thereby providing the protection described above, which was confirmed using PD98059 and U0126. These results indicated that LUWE prevents mitochondrial oxidative stress-mediated RPE damage via the MEK/ERK pathway. Elucidation of the molecular mechanism may provide a new protective strategy against retinal degeneration.

CFH (rs1061170, rs1410996), KDR (rs2071559, rs1870377) and KDR and CFH Serum Levels in AMD Development and Treatment Efficacy

BACKGROUND

Age-related macular degeneration (AMD) is a major global health problem as it is the leading cause of irreversible loss of central vision in the aging population. Av-vascular endothelial growth factor (anti-VEGF) therapies have been shown to be effective, but they do not respond optimally to all patients.

OBJECTIVE

This study investigates the genetic factors associated with susceptibility to AMD and response to treatment, focusing on key polymorphisms in the CFH (rs1061170, rs1410996) and KDR (rs2071559, rs1870377) genes and the association of CFH and KDR serum levels in patients with AMD.

RESULTS

A cohort of 255 patients with early AMD, 252 patients with exudative AMD, and 349 healthy controls underwent genotyping analysis, which revealed significant associations between CFH polymorphisms and the risk of exudative AMD. The CFH rs1061170 CC genotype was associated with an increased risk of early AMD (p = 0.046). For exudative AMD, the CFH rs1061170 TC + CC genotype increased odds (p < 0.001), while the rs1410996 GA + AA genotype decreased odds (p < 0.001). Haplotypes of CFH SNPs were associated with decreased odds of AMD. In terms of response to treatment, none of the SNPs were associated with the response to anti-VEGF treatment. We also found that both early and exudative AMD patients had lower CFH serum levels compared to the control group (p = 0.038 and p = 0.006, respectively). Exudative AMD patients with the CT genotype of CFH rs1061170 had lower CFH serum levels compared to the control group (p = 0.035). Exudative AMD patients with the GG genotype of CFH rs1410996 also had lower CFH serum levels compared to the control group (p = 0.021).

CONCLUSIONS

CFH polymorphisms influence susceptibility to AMD but do not correlate with a response to anti-VEGF therapy. Further research is imperative to fully evaluate the developmental significance, treatment efficacy, and predictive role in influencing susceptibility to anti-VEGF therapy for KDR and CFH.

Exploring Current Molecular Targets in the Treatment of Neovascular Age-Related Macular Degeneration toward the Perspective of Long-Term Agents

Long-lasting anti-vascular endothelial growth factor (anti-VEGF) agents have become an option to reduce treatment frequency, with ongoing research exploring optimal responses and safety profiles. This review delves into molecular targets, pharmacological aspects, and strategies for achieving effective and enduring disease control in neovascular age-related macular degeneration (AMD). The molecular pathways involved in macular neovascularization, including angiogenesis and arteriogenesis, are explored. VEGF, PlGF, Ang-1, and Ang-2 play crucial roles in regulating angiogenesis, influencing vessel growth, maturation, and stability. The complex interplay of these factors, along with growth factors like TGFβ and bFGF, contributes to the pathogenesis of neovascular membranes. Current anti-VEGF therapies, including bevacizumab, ranibizumab, aflibercept, brolucizumab, and faricimab, are discussed with a focus on their pharmacokinetics and clinical applications. Strategies to achieve sustained disease control in AMD involve smaller molecules, increased drug dosages, and novel formulations. This narrative review provides a comprehensive overview of the molecular targets and pharmacological aspects of neovascular AMD treatment.

Compounding engineered mesenchymal stem cell-derived exosomes: A potential rescue strategy for retinal degeneration

The prevalence of retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, has been increasing globally and is linked to the aging population and improved life expectancy. These diseases are characterized by chronic, progressive neuronal damage or depletion of the photoreceptor cells in the retina, and limited effective treatment options are currently available. Mesenchymal stem cell-derived exosomes (MSC-EXOs) containing cytokines, growth factors, lipids, mRNA, and miRNA, which act as mediators of intercellular communication transferring bioactive molecules to recipient cells, offer an appealing, non-cellular nanotherapeutic approach for retinal degenerative diseases. However, treatment specificity is compromised due to their high heterogeneity in size, content, functional effects, and parental cellular source. To improve this, engineered MSC-EXOs with increased drug-loading capacity, targeting ability, and resistance to bodily degradation and elimination have been developed. This review summarizes the recent advances in miRNAs of MSC-EXOs as a treatment for retinal degeneration, discussing the strategies and methods for engineering therapeutic MSC-EXOs. Notably, to address the single functional role of engineered MSC-EXOs, we propose a novel concept called "Compound Engineered MSC-EXOs (Co-E-MSC-EXOs)" along with its derived potential therapeutic approaches. The advantages and challenges of employing Co-E-MSC-EXOs for retinal degeneration in clinical applications, as well as the strategies and issues related to them, are also highlighted.

DRFNet: a deep radiomic fusion network for nAMD/PCV differentiation in OCT images

Objective.Neovascular age-related macular degeneration (nAMD) and polypoidal choroidal vasculopathy (PCV) present many similar clinical features. However, there are significant differences in the progression of nAMD and PCV. and it is crucial to make accurate diagnosis for treatment. In this paper, we propose a structure-radiomic fusion network (DRFNet) to differentiate PCV and nAMD in optical coherence tomography (OCT) images.Approach.The subnetwork (RIMNet) is designed to automatically segment the lesion of nAMD and PCV. Another subnetwork (StrEncoder) is designed to extract deep structural features of the segmented lesion. The subnetwork (RadEncoder) is designed to extract radiomic features from the segmented lesions based on radiomics. 305 eyes (155 with nAMD and 150 with PCV) are included and manually annotated CNV region in this study. The proposed method was trained and evaluated by 4-fold cross validation using the collected data and was compared with the advanced differentiation methods.Main results.The proposed method achieved high classification performace of nAMD/PCV differentiation in OCT images, which was an improvement of 4.68 compared with other best method.Significance. The presented structure-radiomic fusion network (DRFNet) has great performance of diagnosing nAMD and PCV and high clinical value by using OCT instead of indocyanine green angiography.

Recent Developments in Gene Therapy for Neovascular Age-Related Macular Degeneration: A Review

Age-related macular degeneration (AMD) is a complex and multifactorial disease and a leading cause of irreversible blindness in the elderly population. The anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionized the management and prognosis of neovascular AMD (nAMD) and is currently the standard of care for this disease. However, patients are required to receive repeated injections, imposing substantial social and economic burdens. The implementation of gene therapy methods to achieve sustained delivery of various therapeutic proteins holds the promise of a single treatment that could ameliorate the treatment challenges associated with chronic intravitreal therapy, and potentially improve visual outcomes. Several early-phase trials are currently underway, evaluating the safety and efficacy of gene therapy for nAMD; however, areas of controversy persist, including the therapeutic target, route of administration, and potential safety issues. In this review, we assess the evolution of gene therapy for nAMD and summarize several preclinical and early-stage clinical trials, exploring challenges and future directions.

Patterns of Gene Expression, Splicing, and Allele-Specific Expression Vary among Macular Tissues and Clinical Stages of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness, and elucidating its underlying disease mechanisms is vital to the development of appropriate therapeutics. We identified differentially expressed genes (DEGs) and differentially spliced genes (DSGs) across the clinical stages of AMD in disease-affected tissue, the macular retina pigment epithelium (RPE)/choroid and the macular neural retina within the same eye. We utilized 27 deeply phenotyped donor eyes (recovered within a 6 h postmortem interval time) from Caucasian donors (60-94 years) using a standardized published protocol. Significant findings were then validated in an independent set of well-characterized donor eyes (n = 85). There was limited overlap between DEGs and DSGs, suggesting distinct mechanisms at play in AMD pathophysiology. A greater number of previously reported AMD loci overlapped with DSGs compared to DEGs between disease states, and no DEG overlap with previously reported loci was found in the macular retina between disease states. Additionally, we explored allele-specific expression (ASE) in coding regions of previously reported AMD risk loci, uncovering a significant imbalance in C3 rs2230199 and CFH rs1061170 in the macular RPE/choroid for normal eyes and intermediate AMD (iAMD), and for CFH rs1061147 in the macular RPE/choroid for normal eyes and iAMD, and separately neovascular AMD (NEO). Only significant DEGs/DSGs from the macular RPE/choroid were found to overlap between disease states. STAT1, validated between the iAMD vs. normal comparison, and AGTPBP1, BBS5, CERKL, FGFBP2, KIFC3, RORα, and ZNF292, validated between the NEO vs. normal comparison, revealed an intricate regulatory network with transcription factors and miRNAs identifying potential upstream and downstream regulators. Findings regarding the complement genes C3 and CFH suggest that coding variants at these loci may influence AMD development via an imbalance of gene expression in a tissue-specific manner. Our study provides crucial insights into the multifaceted genomic underpinnings of AMD (i.e., tissue-specific gene expression changes, potential splice variation, and allelic imbalance), which may open new avenues for AMD diagnostics and therapies specific to iAMD and NEO.

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.

Neovascular Progression and Retinal Dysfunction in the Laser-Induced Choroidal Neovascularization Mouse Model

The mouse model of laser-induced choroidal neovascularization (LI-CNV) has been widely used to study neovascular age-related macular degeneration; however, it still lacks a comprehensive characterization. Here, CNV was induced in the eyes of 12-week-old C57BL/6J male mice by argon laser irradiation. We studied the CNV lesion progression of an LI-CNV mouse cohort by using multimodal imaging (color fundus, optical coherence tomography (OCT), and fluorescence angiography, focal electroretinography features for 14 days, and related cytokines, angiogenic factors, and reactive gliosis for 5 days. CNV lesions involving the rupture of the Bruch's membrane were confirmed using funduscopy and OCT after laser photocoagulation. During the initial stage, from the CNV induction until day 7, CNV lesions presented leakage observed by using fluorescence angiography and a typical hyperreflective area with cell infiltration, subretinal leakage, and degeneration of photoreceptors observed through OCT. This correlated with decreased retinal responses to light. Moreover, inflammatory and angiogenic markers were reduced to basal levels in the first 5 days of CNV progression. In contrast, reactive gliosis and the VEGF expression in retinal sections were sustained, with infiltration of endothelial cells in the subretinal space. In the second stage, between days 7 and 14 post-induction, we observed stabilization of the CNV lesions, a hyperfluorescent area corresponding to the formation of fibrosis, and a partial rescue of retinal function. These findings suggest that the LI-CNV lesion development goes through an acute phase during the first seven days following induction, and then the CNV lesion stabilizes. According to these results, this model is suitable for screening anti-inflammatory and anti-angiogenic drugs in the early stages of LI-CNV. At the same time, it is more convenient for screening anti-fibrotic compounds in the later stages.

Anti-Scg3 Gene Therapy to Treat Choroidal Neovascularization in Mice

Neovascular age-related macular degeneration (nAMD) with choroidal neovascularization (CNV) is a leading cause of blindness in the elderly in developed countries. The disease is currently treated with anti-angiogenic biologics, including aflibercept, against vascular endothelial growth factor (VEGF) but with limited efficacy, treatment resistance and requirement for frequent intravitreal injections. Although anti-VEGF gene therapy may provide sustained therapy that obviates multiple injections, the efficacy and side effects related to VEGF pathway targeting remain, and alternative strategies to block angiogenesis independently of VEGF are needed. We recently reported that secretogranin III (Scg3) induces only pathological angiogenesis through VEGF-independent pathways, and Scg3-neutralizing antibodies selectively inhibit pathological but not physiological angiogenesis in mouse proliferative retinopathy models. Anti-Scg3 antibodies synergize dose-dependently with VEGF inhibitors in a CNV model. Here, we report that an adeno-associated virus-8 (AAV8) vector expressing anti-Scg3 Fab ameliorated CNV with an efficacy similar to that of AAV-aflibercept in a mouse model. This study is the first to test an anti-angiogenic gene therapy protocol that selectively targets pathological angiogenesis via a VEGF-independent mechanism. The findings support further safety/efficacy studies of anti-Scg3 gene therapy as monotherapy or combined with anti-VEGF to treat nAMD.

3K3A-Activated Protein C Inhibits Choroidal Neovascularization Growth and Leakage and Reduces NLRP3 Inflammasome, IL-1β, and Inflammatory Cell Accumulation in the Retina

3K3A-Activated Protein C (APC) is a recombinant variant of the physiological anticoagulant APC with cytoprotective properties and reduced bleeding risks. We studied the potential use of 3K3A-APC as a multi-target therapeutic option for choroidal neovascularization (CNV), a common cause of vision loss in age-related macular degeneration. CNV was induced by laser photocoagulation in a murine model, and 3K3A-APC was intravitreally injected. The impact of 3K3A-APC treatment on myeloid and microglia cell activation and recruitment and on NLRP3 inflammasome, IL-1β, and VEGF levels was assessed using cryosection, retinal flat-mount immunohistochemistry and vascular imaging. Additionally, we evaluated the use of fluorescein angiography as a surrogate marker for in vivo evaluation of the efficacy of 3K3A-APC treatment against leaking CNV lesions. Our results demonstrated that 3K3A-APC treatment significantly reduced the accumulation and activation of myeloid cells and microglia in the CNV area and decreased the NLRP3 and IL-1β levels at the CNV site and the surrounding retina. Furthermore, 3K3A-APC treatment resulted in leakage regression and CNV growth suppression. These findings indicate that the anti-inflammatory activities of 3K3A-APC contribute to CNV inhibition. Our study suggests the potential use of 3K3A-APC as a novel multi-target treatment for CNV.