Emerging therapies and their delivery for treating age-related macular degeneration

MiRGD peptideticle targeted delivery of hinge-truncated soluble VEGF receptor 1 fusion protein to the retinal pigment epithelium cell line and newborn mice retina

Eye-related Angiogenesis and vascular permeability changes lead to retinal vascular disorders. There is an important need to design a novel targeted anti-VEGF drug delivery system to inhibit neovascularization in the retina. The peptide-based carriers are promising for gene therapy due to their flexibility in design, ease of production, structural diversity, low toxicity, and immunogenicity. The hinge-truncated soluble VEGF receptor 1 (htsFLT01) protein, has the ability to bind to both VEGF and PlGF molecules. In the present study, htsFLT01 gene delivery by targeted MiRGD peptide carrier was investigated in the mouse Retinal Pigment Epithelium (mRPE) cell line and mouse model to evaluate the potential of the newly developed peptideticle as an effective therapeutic platform for gene delivery. The characterization results demonstrated that the peptide carrier condensed htsFLT01 DNA, neutralizes its negative charge, and protected it from endonucleases. The size and charge of the nanocomplexes were optimized to effectively target the retina. Based on tube formation assay, migration analyses and intravitreal injection of MiRGD-htsFLT01 nanocomplex into the newborn mice eye, the function of htsFLT01 was investigated. The reduction of tube-like structures in HUVEC cells was notably observed following VEGF neutralization and the findings demonstrated an association between the expression of htsFLT01 and the inhibition of RPE cell migration. The vascular development was inhibited in the deep, intermediate, and superficial capillary plexus layers in the retina. The novel drug MiRGD/htsFLT01 complex, represents a promising potential platform for targeted gene therapy in the eye due to its biocompatibility, likely safety and highly effective function.

Retinal Protective Effect of Mono-Ethyl Fumarate in Experimental Age-Related Macular Degeneration via Anti-Oxidative and Anti-Apoptotic Alterations

Age-related macular degeneration (AMD) is a leading cause of vision impairment in people over the age of 60. Currently, the FDA-approved drugs for AMD have various side effects, and there is a notable lack of drug development for dry AMD. This study aimed to explore the therapeutic effects of mono-ethyl fumarate (MEF) on AMD. MEF effectively protected ARPE-19 cells from cell death induced by a combination of A2E and blue light exposure. In a C57BL/6J mouse model of retinal degeneration caused by sodium iodate, MEF played a role in preserving retinal thickness and maintaining the layered structure of the retina. It was assessed via fundus imaging, optical coherence tomography, and hematoxylin and eosin staining. Treatment with MEF significantly increased the expression of antioxidant proteins such as HO-1, NQO1, and SOD1 in ARPE-19 cells. Additionally, treatment with MEF significantly increased the levels of the antioxidant proteins SOD1 and GPX4 in the mouse retina. Concurrently, it significantly reduced the levels of apoptosis-related factors, such as the Bax/Bcl-2 ratio and Caspase -3 cleavage. These findings suggest that MEF may represent a promising therapeutic candidate for the management of AMD.

Evidence for a Functional Link Between the Nrf2 Signalling Pathway and Cytoprotective Effect of S-Petasin in Human Retinal Pigment Epithelium Cells Exposed to Oxidative Stress

The retinal pigment epithelium (RPE) is a highly specialised monolayer epithelium subjected to constant oxidative stress, which, in the long term, favours the development of a complex pathological process that is the underlying cause of macular damage. Therefore, counteracting the overproduction of ROS is the best-researched approach to preserve the functional integrity of the RPE. S-Petasin, a secondary metabolite extracted from the plant Petasites hybridus, has numerous biological effects, which highlight its anti-inflammatory and antioxidative properties. The aim of our study is to investigate whether S-Petasin exerts cytoprotective effects by protecting the RPE from oxidative damage. The effects of pretreatment with S-Petasin were assessed by the determination of the cell viability, intracellular ROS levels, activation of the Nrf2 pathway and the resulting post-transcriptional antioxidant/antiapoptotic response. Our results show that S-Petasin pretreatment (1) reduces intracellular ROS levels, improving cell viability of RPE exposed to oxidative damage; (2) activates the Nrf2 signalling pathway, modulating the post-transcriptional response of its antioxidant chemical biomarkers; (3) reduces the Bax levels, and an increase in those of Bcl-2, with a concomitant downregulation of the Bax/Bc-2 ratio. Overall, our results provide the first evidence that S-Petasin is able to protect the RPE from oxidative damage.

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.

DEEP LEARNING FOR AUTOMATIC PREDICTION OF EARLY ACTIVATION OF TREATMENT-NAIVE NONEXUDATIVE MACULAR NEOVASCULARIZATIONS IN AGE-RELATED MACULAR DEGENERATION

BACKGROUND

Around 30% of nonexudative macular neovascularizations exudate within 2 years from diagnosis in patients with age-related macular degeneration. The aim of this study is to develop a deep learning classifier based on optical coherence tomography (OCT) and OCT angiography (OCTA) to identify nonexudative macular neovascularizations at risk of exudation.

METHODS

Patients with age-related macular degeneration showing OCTA and fluorescein angiography-documented nonexudative macular neovascularization with a 2-year minimum imaging follow-up were retrospectively selected. Patients showing OCT B-scan-documented macular neovascularization exudation within the first 2 years formed the EX GROUP while the others formed the QU GROUP. ResNet-101, Inception-ResNet-v2, and DenseNet-201 were independently trained on OCTA and OCT B-scan images. Combinations of the six models were evaluated with major and soft voting techniques.

RESULTS

Eighty-nine eyes of 89 patients with a follow-up of 5.7 ± 1.5 years were recruited (35 EX GROUP and 54 QU GROUP). Inception-ResNet-v2 was the best performing among the three single convolutional neural networks. The major voting model resulting from the association of the three different convolutional neural networks resulted in an improvement of performance both for OCTA and OCT B-scan (both significantly higher than human graders' performance). The soft voting model resulting from the combination of OCTA and OCT B-scan-based major voting models showed a testing accuracy of 94.4%. Peripheral arcades and large vessels on OCTA en face imaging were more prevalent in the QU GROUP.

CONCLUSION

Artificial intelligence shows high performances in identifications of nonexudative macular neovascularizations at risk for exudation within the first 2 years of follow-up, allowing better customization of follow-up timing and avoiding treatment delay. Better results are obtained with the combination of OCTA and OCT B-scan image analysis.

Interferons in vitreoretinal diseases; a review on their clinical application, and mechanism of action

PURPOSE

This review investigates the therapeutic benefits of interferons (IFNs) in vitreoretinal diseases, focusing on their regulatory roles in innate immunological reactions and angiogenesis. The study aims to categorize the clinical outcomes of IFN applications and proposes a molecular mechanism underlying their action.

METHODS

A systematic review was conducted using MEDLINE/PubMed, Web of Science, EMBASE, and Google Scholar databases to identify randomized clinical trials, case series, and case-control studies related to IFNs' impact on vitreoretinal diseases (1990-2022). The data synthesis involved an in-depth analysis of the anti-inflammatory and anti-angiogenesis effects of IFNs across various studies.

RESULTS

Our findings indicate that IFNs exhibit efficacy in treating inflammation-associated vitreoretinal disorders. However, a lack of sufficient evidence exists regarding the suitability of IFNs in angiogenesis-associated vitreoretinal diseases like choroidal neovascularization and diabetic retinopathies. The synthesis of data suggests that IFNs may not be optimal for managing advanced stages of angiogenesis-associated disorders.

CONCLUSION

While IFNs emerge as promising therapeutic candidates for inflammation-related vitreoretinal diseases, caution is warranted in their application for angiogenesis-associated disorders, especially in advanced stages. Further research is needed to elucidate the nuanced molecular pathways of IFN action, guiding their targeted use in specific vitreoretinal conditions.

Eye Drop with Fas-Blocking Peptide Attenuates Age-Related Macular Degeneration

Age-related macular degeneration (AMD), characterized by macular retinal degeneration, poses a significant health concern due to the lack of effective treatments for prevalent dry AMD. The progression of AMD is closely linked to reactive oxygen species and Fas signaling, emphasizing the need for targeted interventions. In this study, we utilized a NaIO3-induced retinal degeneration mouse model to assess the efficacy of Fas-blocking peptide (FBP). Intravitreal administration of FBP successfully suppressed Fas-mediated inflammation and apoptosis, effectively arresting AMD progression in mice. We developed a 6R-conjugated FBP (6R-FBP) for eye drop administration. 6R-FBP, administered as an eye drop, reached the retinal region, attenuating degeneration by modulating the expression of inflammatory cytokines and blocking Fas-mediated apoptosis in rodent and rabbit NaIO3-induced retinal degeneration models to address practical concerns. Intravitreal FBP and 6R-FBP eye drops effectively reduced retinal degeneration and improved retinal thickness in rodent and rabbit models. This study highlights the therapeutic potential of FBP, particularly 6R-FBP as an eye drop, in inhibiting Fas-mediated cell signaling and protecting against retinal cell death and inflammation in dry AMD. Future investigations should explore the translational prospects of this approach in primates with eye structures comparable to those of humans.

Topical Application of Cell-Penetrating Peptide Modified Anti-VEGF Drug Alleviated Choroidal Neovascularization in Mice

Background

Age-related macular degeneration (AMD) stands as the foremost cause of irreversible central vision impairment, marked by choroidal neovascularization (CNV). The prevailing clinical approach to AMD treatment relies on intravitreal injections of anti-vascular endothelial growth factor (VEGF) drugs. However, this method is encumbered by diverse complications, prompting exploration of non-invasive alternatives such as ocular administration via eye drops for anti-VEGF therapy.

Methods

Two complexes, 5-FITC-CPP-Ranibizumab (5-FCR) and 5-FITC-CPP-Conbercept (5-FCC), were synthesized by incorporating the anti-VEGF drugs Ranibizumab (RBZ) or Conbercept (CBC) with cell-penetrating peptide (CPP). Circular dichroism spectrum (CD) facilitated complexes characterization. Eye drops was utilized to address laser-induced CNV in mice. Fluorescein fundus angiography (FFA) observe the CNV lesion, while FITC-dextran and IB4 dual fluorescent staining, along with hematoxylin-eosin (HE) staining, assessed in lesion size. Tissue immunofluorescence examined CD31 and VEGF expression in choroidal/retinal pigment epithelial (RPE) tissues. Biocompatibility and biosafety of 5-FCR and 5-FCC was evaluated through histological examination of various organs or cell experiments.

Results

Both 5-FCR and 5-FCC exhibited favorable biocompatibility and safety profiles. VEGF-induced migration of Human umbilical vein endothelial cells (HUVECs) significantly decreased post-5-FCR/5-FCC treatment. Additionally, both complexes suppressed VEGF-induced tube formation in HUVECs. FFA results revealed a significant improvement in retinal exudation in mice. Histological examination unveiled the lesion areas in the 5-FCR and 5-FCC groups showed a significant reduction compared to the control group. Similar outcomes were observed in histological sections of the RPE-choroid-sclera flat mounts.

Conclusion

In this study, utilizing the properties of CPP and two anti-VEGF drugs, we successfully synthesized two complexes, 5-FCR and 5-FCC, through a straightforward approach. Effectively delivering the anti-VEGF drugs to the target area in a non-invasive manner, suppressing the progression of laser-induced CNV. This offers a novel approach for the treatment of wet AMD.

AAV-Based Strategies for Treatment of Retinal and Choroidal Vascular Diseases: Advances in Age-Related Macular Degeneration and Diabetic Retinopathy Therapies

Age-related macular degeneration (AMD) and diabetic retinopathy (DR) are vascular diseases with high prevalence, ranking among the leading causes of blindness and vision loss worldwide. Despite being effective, current treatments for AMD and DR are burdensome for patients and clinicians, resulting in suboptimal compliance and real risk of vision loss. Thus, there is an unmet need for long-lasting alternatives with improved safety and efficacy. Adeno-associated virus (AAV) is the leading vector for ocular gene delivery, given its ability to enable long-term expression while eliciting relatively mild immune responses. Progress has been made in AAV-based gene therapies for not only inherited retinal diseases but also acquired conditions with preclinical and clinical studies of AMD and DR showing promising results. These studies have explored several pathways involved in the disease pathogenesis, as well as different strategies to optimise gene delivery. These include engineered capsids with enhanced tropism to particular cell types, and expression cassettes incorporating elements for a targeted and controlled expression. Multiple-acting constructs have also been investigated, in addition to gene silencing and editing. Here, we provide an overview of strategies employing AAV-mediated gene delivery to treat AMD and DR. We discuss preclinical efficacy studies and present the latest data from clinical trials for both diseases.

Research on an artificial intelligence-based myopic maculopathy grading method using EfficientNet

PURPOSE

We aimed to develop an artificial intelligence-based myopic maculopathy grading method using EfficientNet to overcome the delayed grading and diagnosis of different myopic maculopathy degrees.

METHODS

The cooperative hospital provided 4642 healthy and myopic maculopathy color fundus photographs, comprising the four degrees of myopic maculopathy and healthy fundi. The myopic maculopathy grading models were trained using EfficientNet-B0 to EfficientNet-B7 models. The diagnostic results were compared with those of the VGG16 and ResNet50 classification models. The leading evaluation indicators were sensitivity, specificity, F1 score, area under the receiver operating characteristic (ROC) curve area under curve (AUC), 95% confidence interval, kappa value, and accuracy. The ROC curves of the ten grading models were also compared.

RESULTS

We used 1199 color fundus photographs to evaluate the myopic maculopathy grading models. The size of the EfficientNet-B0 myopic maculopathy grading model was 15.6 MB, and it had the highest kappa value (88.32%) and accuracy (83.58%). The model's sensitivities to diagnose tessellated fundus (TF), diffuse chorioretinal atrophy (DCA), patchy chorioretinal atrophy (PCA), and macular atrophy (MA) were 96.86%, 75.98%, 64.67%, and 88.75%, respectively. The specificity was above 93%, and the AUCs were 0.992, 0.960, 0.964, and 0.989, respectively.

CONCLUSION

The EfficientNet models were used to design grading diagnostic models for myopic maculopathy. Based on the collected fundus images, the models could diagnose a healthy fundus and four types of myopic maculopathy. The models might help ophthalmologists to make preliminary diagnoses of different degrees of myopic maculopathy.

Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration

The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.

Ocular Delivery of Therapeutic Agents by Cell-Penetrating Peptides

Cell-penetrating peptides (CPPs) are short peptides with the ability to translocate through the cell membrane to facilitate their cellular uptake. CPPs can be used as drug-delivery systems for molecules that are difficult to uptake. Ocular drug delivery is challenging due to the structural and physiological complexity of the eye. CPPs may be tailored to overcome this challenge, facilitating cellular uptake and delivery to the targeted area. Retinal diseases occur at the posterior pole of the eye; thus, intravitreal injections are needed to deliver drugs at an effective concentration in situ. However, frequent injections have risks of causing vision-threatening complications. Recent investigations have focused on developing long-acting drugs and drug delivery systems to reduce the frequency of injections. In fact, conjugation with CPP could deliver FDA-approved drugs to the back of the eye, as seen by topical application in animal models. This review summarizes recent advances in CPPs, protein/peptide-based drugs for eye diseases, and the use of CPPs for drug delivery based on systematic searches in PubMed and clinical trials. We highlight targeted therapies and explore the potential of CPPs and peptide-based drugs for eye diseases.

Novel Approaches in the Drug Development and Delivery Systems for Age-Related Macular Degeneration

The number of patients with ocular disorders has increased due to contributing factors such as aging populations, environmental changes, smoking, genetic abnormalities, etc. Age-related macular degeneration (AMD) is one of the common ocular disorders which may advance to loss of vision in severe cases. The advanced form of AMD is classified into two types, dry (non-exudative) and wet (exudative) AMD. Although several therapeutic approaches are explored for the management of AMD, no approved therapy can substantially slow down the progression of dry AMD into the later stages. The focus of researchers in recent times has been engaged in developing targeted therapeutic products to halt the progression and maintain or improve vision in individuals diagnosed with AMD. The delivery of anti-VEGF agents using intravitreal therapy has found some success in managing AMD, and novel formulation approaches have been introduced in various studies to potentiate the efficacy. Some of the novel approaches, such as hydrogel, microspheres, polymeric nanoparticles, liposomes, implants, etc. have been discussed. Apart from this, subretinal, suprachoroidal, and port delivery systems have also been investigated for biologics and gene therapies. The unmet potential of approved therapeutic products has contributed to several patent applications in recent years. This review outlines the current treatment options, outcomes of recent research studies, and patent details around the novel drug delivery approach for the treatment of AMD.

Proteomics profiling of vitreous humor reveals complement and coagulation components, adhesion factors, and neurodegeneration markers as discriminatory biomarkers of vitreoretinal eye diseases

Introduction

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are leading causes of visual impairment and blindness in people aged 50 years or older in middle-income and industrialized countries. Anti-VEGF therapies have improved the management of neovascular AMD (nAMD) and proliferative DR (PDR), no treatment options exist for the highly prevalent dry form of AMD.

Methods

To unravel the biological processes underlying these pathologies and to find new potential biomarkers, a label-free quantitative (LFQ) method was applied to analyze the vitreous proteome in PDR (n=4), AMD (n=4) compared to idiopathic epiretinal membranes (ERM) (n=4).

Results and discussion

Post-hoc tests revealed 96 proteins capable of differentiating among the different groups, whereas 118 proteins were found differentially regulated in PDR compared to ERM and 95 proteins in PDR compared to dry AMD. Pathway analysis indicates that mediators of complement, coagulation cascades and acute phase responses are enriched in PDR vitreous, whilst proteins highly correlated to the extracellular matrix (ECM) organization, platelet degranulation, lysosomal degradation, cell adhesion, and central nervous system development were found underexpressed. According to these results, 35 proteins were selected and monitored by MRM (multiple reaction monitoring) in a larger cohort of patients with ERM (n=21), DR/PDR (n=20), AMD (n=11), and retinal detachment (n=13). Of these, 26 proteins could differentiate between these vitreoretinal diseases. Based on Partial least squares discriminant and multivariate exploratory receiver operating characteristic (ROC) analyses, a panel of 15 discriminatory biomarkers was defined, which includes complement and coagulation components (complement C2 and prothrombin), acute-phase mediators (alpha-1-antichymotrypsin), adhesion molecules (e.g., myocilin, galectin-3-binding protein), ECM components (opticin), and neurodegeneration biomarkers (beta-amyloid, amyloid-like protein 2).

Intraocular delivery considerations of ocular biologic products and key preclinical determinations

INTRODUCTION

Ophthalmic diseases of the retina are a significant cause of vision loss globally. Despite much progress, there remains an unmet need for durable, long-acting treatment options. While biologic therapies show great promise, they present many challenges, including complexities in biochemical properties, mechanism of action, manufacturing considerations, preclinical evaluation, and delivery mechanism; these are confounded by the unique anatomy and physiology of the eye itself.

AREAS COVERED

This review describes the current development status of intravitreally administered drugs for the treatment of ophthalmic disease, outlines the range of approaches that can be considered for sustained drug delivery to the eye, and discusses key preclinical considerations for the evaluation of ocular biologics.

EXPERT OPINION

The required frequency of dosing in the eye results in a great burden on both patients and the health care system, with direct intraocular administration remaining the most reliable and predictable route. Sustained and controlled ophthalmic drug delivery systems will go a long way in reducing this burden. Sustained delivery can directly dose target tissues, improving bioavailability and reducing off-target systemic effects. Maintaining stability and activity of compounds can prevent aggregation and enable extended duration of release, while sustaining dosage and preventing residual polymer after drug depletion.

Vitreous humor proteome: unraveling the molecular mechanisms underlying proliferative and neovascular vitreoretinal diseases

Proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and neovascular age-related macular degeneration (nAMD) are among the leading causes of blindness. Due to the multifactorial nature of these vitreoretinal diseases, omics approaches are essential for a deeper understanding of the pathophysiologic processes underlying the evolution to a proliferative or neovascular etiology, in which patients suffer from an abrupt loss of vision. For many years, it was thought that the function of the vitreous was merely structural, supporting and protecting the surrounding ocular tissues. Proteomics studies proved that vitreous is more complex and biologically active than initially thought, and its changes reflect the physiological and pathological state of the eye. The vitreous is the scenario of a complex interplay between inflammation, fibrosis, oxidative stress, neurodegeneration, and extracellular matrix remodeling. Vitreous proteome not only reflects the pathological events that occur in the retina, but the changes in the vitreous itself play a central role in the onset and progression of vitreoretinal diseases. Therefore, this review offers an overview of the studies on the vitreous proteome that could help to elucidate some of the pathological mechanisms underlying proliferative and/or neovascular vitreoretinal diseases and to find new potential pharmaceutical targets.

An Altered Neurovascular System in Aging-Related Eye Diseases

The eye has a complex and metabolically active neurovascular system. Repeated light injuries induce aging and trigger age-dependent eye diseases. Damage to blood vessels is related to the disruption of the blood-retinal barrier (BRB), altered cellular communication, disrupted mitochondrial functions, and exacerbated aggregated protein accumulation. Vascular complications, such as insufficient blood supply and BRB disruption, have been suggested to play a role in glaucoma, age-related macular degeneration (AMD), and Alzheimer's disease (AD), resulting in neuronal cell death. Neuronal loss can induce vision loss. In this review, we discuss the importance of the neurovascular system in the eye, especially in aging-related diseases such as glaucoma, AMD, and AD. Beneficial molecular pathways to prevent or slow down retinal pathologic processes will also be discussed.

The effect of vitreomacular interface in neovascular age-related macular degeneration treated with intravitreal injection of anti-VEGF

BACKGROUND

The purpose of this study is to study the effect of repeated intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) drugs on vitreomacular interface.

METHODS

Neovascular age-related macular degeneration patients who received intravitreal injections of anti-VEGF drugs were included. Eyes with severe vitreous opacity, uveitis, complicated cataract surgery and previous vitrectomy were excluded. Vitreomacular interface, best corrected visual acuity (BCVA) and central retinal thickness (CRT) assessment were performed once a month for at least 3 months. The nature and time of the change event are recorded. Groups were divided according to whether vitreomacular interface change events occurred. To analyse the risk factors of vitreomacular interface changes and their influence on treatment effect.

RESULTS

A total of 87 eyes were evaluated. Vitreomacular interface change event occurred in 9 eyes. Pre-existing vitreomacular interface abnormality (VMIA) was a risk factor for the VMI change (P = 0.033, OR = 16.518, 95% CI: 1.258 to 216.939). 60% of interface events occurred in the first 3 months of treatment. The final BCVA of eyes with vitreomacular interface unchanged was significantly higher than that at baseline (P = 0.001), and the final CRT was also significantly lower than that at baseline (P < 0.001). The final CRT of eyes vitreomacular interface changed was significantly lower than that at baseline (P = 0.015), however, there was no statistical significance in BCVA (P = 0.468).

CONCLUSION

Intravitreal injection of anti-VEGF drugs has a certain probability to cause changes in the vitreomacular interface, and the risk is higher in eyes with pre-existing vitreomacular interface abnormality. The effect of intravitreal injections on the vitreomacular interface was concentrated in the first three injections, and subsequent increases in the number of injections did not significantly increase the risk of vitreomacular interface abnormality. Ophthalmologists should increase attention to the vitreomacular interface in the early stages of anti-VEGF therapy and counsel patients accordingly.

Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications

Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.

Treatment and prevention of pathological mitochondrial dysfunction in retinal degeneration and in photoreceptor injury

Pathological deterioration of mitochondrial function is increasingly linked with multiple degenerative illnesses as a mediator of a wide range of neurologic and age-related chronic diseases, including those of genetic origin. Several of these diseases are rare, typically defined in the United States as an illness affecting fewer than 200,000 people in the U.S. population, or about one in 1600 individuals. Vision impairment due to mitochondrial dysfunction in the eye is a prominent feature evident in numerous primary mitochondrial diseases and is common to the pathophysiology of many of the familiar ophthalmic disorders, including age-related macular degeneration, diabetic retinopathy, glaucoma and retinopathy of prematurity - a collection of syndromes, diseases and disorders with significant unmet medical needs. Focusing on metabolic mitochondrial pathway mechanisms, including the possible roles of cuproptosis and ferroptosis in retinal mitochondrial dysfunction, we shed light on the potential of α-lipoyl-L-carnitine in treating eye diseases. α-Lipoyl-L-carnitine is a bioavailable mitochondria-targeting lipoic acid prodrug that has shown potential in protecting against retinal degeneration and photoreceptor cell loss in ophthalmic indications.

Gene Delivery of a Caspase Activation and Recruitment Domain Improves Retinal Pigment Epithelial Function and Modulates Inflammation in a Mouse Model with Features of Dry Age-Related Macular Degeneration

Purpose: The NLRP3 inflammasome, a cytoplasmic signal transduction complex that regulates inflammation, has been implicated in the pathogenesis of age-related macular degeneration (AMD), the leading cause of visual impairment in industrialized countries. We tested the therapeutic effect of anti-inflammatory gene therapy, delivered preventively, in Liver-X-Receptor alpha knockout (LXRα^-/-) mice, which exhibit features of dry AMD. Methods:LXRα^-/- mice were treated with an adeno-associated virus (AAV) vector that delivers a secretable and cell-penetrating form of the caspase activation and recruitment domain (CARD). A sGFP-FCS-TatCARD-AAV or sGFP-FCS (control) vector was delivered intravitreally to 3-5 month-old, LXRα^-/- mice, who were then aged to 15-18 months (12-13 month treatment). Retinal function and morphology were assessed pre- and post-treatment. Results: TatCARD treated LXRα^-/- mice did not show improvement in rod and cone photoreceptor function, measured by dark adapted a- and b-wave amplitudes, and rod-saturated b-wave amplitudes. We found a sex-dependent, significant therapeutic effect in c-wave amplitudes in the TatCARD treated mice, which exhibited maintenance of amplitudes in comparison to the significant decline recorded in the control treated group, indicating a therapeutic effect mediated in part through retinal pigment epithelial (RPE) cells. Additionally, the retinas of the TatCARD treated mice exhibited a significant decline in the concentration of interleukin-1 beta (IL-1β) concomitant with modulation of several inflammatory cytokines in the retina and RPE-choroid tissues, as measured by ELISA and cytokine array, respectively. Conclusion: Collectively, these results support that anti-inflammatory gene constructs such as AAV-TatCARD may be considered for the treatment of inflammation in AMD and other ocular diseases of the posterior pole in which inflammation may play a role. Furthermore, our findings emphasize the need to carefully consider potential sex-different responses when assessing potential therapies in pre-clinical models.

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

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

Topical Drug Delivery to the Posterior Segment of the Eye

Topical drug delivery to the posterior segment of the eye is a very complex challenge. However, topical delivery is highly desired, to achieve an easy-to-use treatment option for retinal diseases. In this review, we focus on the drug characteristics that are relevant to succeed in this challenge. An overview on the ocular barriers that need to be overcome and some relevant animal models to study ocular pharmacokinetics are given. Furthermore, a summary of substances that were able to reach the posterior segment after eye drop application is provided, as well as an outline of investigated delivery systems to improve ocular drug delivery. Some promising results of substances delivered to the retina suggest that topical treatment of retinal diseases might be possible in the future, which warrants further research.