Current advances in the treatment of neovascular age-related macular degeneration

Retinal and choroidal changes after anti-VEGF therapy in neovascular-AMD patients: A systematic review and meta-analysis of SD-OCT studies

BACKGROUND

In recent years, the progress made in the field of optical coherence tomography has helped to understand the changes in eye layers in patients with exudative age-related macular degeneration (nAMD). Early diagnosis of nAMD, a leading cause of irreversible vision impairment, is helpful. Therefore, we performed a meta-analysis on OCT measurement alterations before and after anti-VEGF therapy in patients with nAMD and controls.

METHOD

We systematically searched Scopus, PubMed, Cochrane, and Web of Science to find articles that measured choroidal and retinal layer changes after anti-VEGF therapy in nAMD Patients. We chose either a fixed-effects or random-effects model based on the assessed heterogeneity level to perform a meta-analysis. In addition, we conducted meta-regression, subgroup analyses, publication bias, and quality assessment for included studies.

RESULTS

Thirteen studies were included in the meta-analysis, with 733 total participants. Foveal thickness and subfoveal choroidal thickness (CT) decreased significantly in the first 3 years after injections, except for subfoveal CT in the third year after injection. It also showed that CT at 1500 µm temporal and nasal to the fovea did not significantly change.

CONCLUSION

Our results showed anti-VEGF treatment for nAMD patients was associated with a significant reduction in foveal thickness and subfoveal CT in the first 2 years after treatment. Our analysis did not reveal any correlation between changes in foveal thickness and subfoveal CT with best-corrected visual acuity or other factors.

Selective microRNA expression of exosomes from retinal pigment epithelial cells by oxidative stress

The function of exosomal miRNAs (miRs) in retinal degeneration is largely unclear. We were aimed to investigate the functions of exosomes as well as their miRs derived from retinal pigment epithelial (RPE) cells following exposure to oxidative stress (OS). After the OS by lipopolysaccharide and rotenone on RPE cells, interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumor Necrosis Factor-alpha (TNF-α) were upregulated, along with the decreased mitochondrial membrane potential and upregulated oxidative damage marker 8-OH-dG in RPE cells. RPE-derived exosomes were then isolated, identified, injected into the subretinal space in mice. After subretinal injection, RPE-exosomes after OS not only induced higher ROS level and apoptotic retinal cells, but also elevated IL-1β, IL-6 alongside TNF-α expressions among retina/RPE/choroidal complex. Next, miRs inside the exosomes were sequenced by the next generation sequencing (NGS) technology. NGS revealed that certain miRs were abundant in exosomes, while others were selectively kept by RPE cells. Further, downregulated miRs, like miR-125b-5p, miR-125a-5p, alongside miR-128-3p, and upregulated miR, such as miR-7-5p were validated byRT-qPCR. Finally, Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to find the possible target genes of those selective exosomal miRs. Our results proved that the RPE-derived exosomes after OS selectively express certain miRs, providing novel insights into the pathogenesis of age-related macular degeneration (AMD) in future.

Current Insights into Targeting Strategies for the Effective Therapy of Diseases of the Posterior Eye Segment

The eye is one a unique sophisticated human sense organ with a complex anatomical structure. It is encased by variety of protective barriers as responsible for vision. There has been a paradigm shift in the prevalence of several major vision threatening ocular conditions with enhanced reliance on computer-based technologies in our workaday life and work-from-home modalities although aging, pollution, injury, harmful chemicals, lifestyle changes will always remain the root cause. Treating posterior eye diseases is a challenge faced by clinicians worldwide. The clinical use of conventional drug delivery systems for posterior eye targeting is restricted by the ocular barriers. Indeed, for overcoming various ocular barriers for efficient delivery of the therapeutic moiety and prolonged therapeutic effect requires prudent and target-specific approaches. Therefore, for efficient drug delivery to the posterior ocular segment, advancements in the development of sustained release and nanotechnology-based ocular drug delivery systems have gained immense importance. Therapeutic efficacy and patient compliance are of paramount importance in clinical translation of these investigative drug delivery systems. This review provides an insight into the various strategies employed for improving the treatment efficacies of the posterior eye diseases. Various drug delivery systems such as systemic and intraocular injections, implants have demonstrated promising outcomes, along with that they have also exhibited side-effects, limitations and strategies employed to overcome them are discussed in this review. The application of artificial intelligence-based technologies along with an appreciation of disease, delivery systems, and patient-specific outcomes will likely enable more effective therapy for targeting the posterior eye segment.

Long-term blue light exposure impairs mitochondrial dynamics in the retina in light-induced retinal degeneration in vivo and in vitro

Long-term light exposure, especially in the spectrum of blue light, frequently causes excessive oxidative stress in dry age-related macular degeneration (AMD). Here, to gain insight into the underlying mechanism, we focused on mitochondrial dynamics alterations under long-term exposure to blue light in mouse and retinal cells. Six-month-old C57BL/6 mice were exposed to blue light (450 nm, 800 lx) for 2 weeks. The phenotypic changes in the retina were assayed using haematoxylin-eosin staining and transmission electron microscopy. Long-term blue light exposure significantly thinned each retinal layer in mice, induced retinal apoptosis and impaired retinal mitochondria. A retinal pigment epithelial cell line (ARPE-19) was used to verify the phototoxicity of blue light. Flow cytometry, immunofluorescence and MitoSox Red probe experiments confirmed that more total and mitochondria-specific ROS were generated in the blue light group than in the control group. Mito-Tracker Green probe showed fragmented mitochondrial morphology. The western blotting results indicated a significant increase in DRP1, OMA1, and BAX and a decrease in OPA1 and Bcl-2. In conclusion, long-term exposure to blue light damaged the retinas of mice, especially the ONL and RPE cells. There was destruction and dysfunction of mitochondria in RPE cells in vivo and in vitro. Mitochondrial dynamics were disrupted with characteristics of fusion-related obstruction after blue-light irradiation.

Novel metrics for evaluating decision making in a 'Treat and Extend' regimen for neovascular age related macular degeneration

BACKGROUND

The primary aim was to investigate outcome of the decision making on duration of injection intervals between injection visits over the first 2 years of a treat and extend regimen.

METHOD

Consecutive patients receiving Aflibercept for treatment naïve neovascular age-related macular degeneration between 01.01.2016 and 15.07.2017 were identified from our departmental register. Retrospective data collected on all visits over 24 months were classified into three groups: (A) Without Interval Decision Events (IDE)" Injection only" (B) IDE resulting in injection intervals of <5 weeks and (C) IDE resulting in intervals of >5 weeks. The primary outcome was number of successful IDE relative to the total visits in Group C. Successful decision making was defined as absence of worsening of visual acuity (>5 L) or central retinal thickness (>50 microns) at the subsequent visit. Secondary visual and anatomical outcomes at 24 months were also evaluated.

RESULTS

Data from 56 eyes of 50 patients were included in the study. Visual acuity improved by +7.11 L at 24 months. Forty one patients with unilateral therapy made 721 visits: 280 visits (38.8%) were group A; 164 visits (22.8%) were group B and 277 visits (38.4%) were group C. Average interval in Group C was 8.9 weeks (range 5-15). The success rate of extension was 95.31% (264/277 visits).

CONCLUSION

These metrics for evaluating the decision making aspect of disease activity monitoring may be useful for monitoring performance and have given us a more realistic view and expectations of what can be achieved using this regime to optimise the timing of injections.

Genomewide Association Study of Retinal Traits in the Amish Reveals Loci Influencing Drusen Development and Link to Age-Related Macular Degeneration

Purpose

The purpose of this study was to identify genetic risk loci for retinal traits, including drusen, in an Amish study population and compare these risk loci to known risk loci of age-related macular degeneration (AMD).

Methods

Participants were recruited from Amish communities in Ohio, Indiana, and Pennsylvania. Each participant underwent a basic health history, ophthalmologic examination, and genotyping. A genomewide association analysis (GWAS) was conducted for the presence and quantity of each of three retinal traits: geographic atrophy, drusen area, and drusen volume. The findings were compared to results from a prior large GWAS of predominantly European-ancestry individuals. Further, a genetic risk score for AMD was used to predict the presence and quantity of the retinal traits.

Results

After quality control, 1074 participants were included in analyses. Six single nucleotide polymorphisms (SNPs) met criteria for genomewide significance and 48 were suggestively associated across three retinal traits. The significant SNPs were not highly correlated with known risk SNPs for AMD. A genetic risk score for AMD provided significant predictive value of the retinal traits.

Conclusions

We identified potential novel genetic risk loci for AMD in a midwestern Amish study population. Additionally, we determined that there is a clear link between the genetic risk of AMD and drusen. Further study, including longitudinal data collection, may improve our ability to define this connection and improve understanding of the biological risk factors underlying drusen development.

COL10A1 is a novel factor in the development of choroidal neovascularization

With the dramatic rise in the aging population, researching age-related macular degeneration (AMD), especially the severe form neovascular AMD (nAMD), has become more important than ever. In this study, we found that collagen type X was increased in retina-choroid tissue of mice with laser-induced choroidal neovascularization (CNV) based on immunohistofluorescence. RNA sequencing and bioinformatic analyses were performed to compare the retina-choroid tissue complex of the CNV mouse model to normal controls. Collagen type X alpha 1 chain (Col10a1) was among the most significantly upregulated genes, and the results were validated with an animal model at the mRNA and protein levels by quantitative real-time polymerase chain reaction (qPCR) and western blotting, respectively. COL10A1 was also upregulated in human retinal microvascular endothelial cells (HRMECs), human umbilical vein endothelial cells (HUVECs), RPE19 cells and RF/6A cells under hypoxic conditions. Next, in vitro and in vivo experiments were performed to study the effect of COL10A1 on neovascularization. siRNA knockdown of COL10A1 suppressed the proliferation and tube formation ability of HRMECs under hypoxic conditions. Snail family transcriptional repressor 1 (SNAIL1) and angiopoietin-2 (ANGPT2) were downregulated in COL10A1 knockdown HRMECs under hypoxic conditions and thus were potential downstream genes. Significant decreases in CNV leakage and CNV lesion area, as assessed by fundus fluorescein angiography (FFA) and immunofluorescence of choroidal flat mounts, respectively, were observed in a mouse model intravitreally injected with anti-collagen X monoclonal antibody (mAb) compared to the controls. In conclusion, COL10A1 promotes CNV formation and may represent a new candidate target for the treatment and diagnosis of nAMD and other neovascular diseases.

Three-Year Outcomes of Wet Age-Related Macular Degeneration Treatment in Polish Therapeutic Programs

Background and Objectives: Wet age-related macular degeneration (wAMD) is a chronic, progressive disease of the central part of the retina. Standard treatment for wAMD consists of multiple intravitreal injections of anti-vascular endothelial growth factor drugs. The study goal was to evaluate the three-year effectiveness of wAMD treatment with aflibercept and ranibizumab as part of the therapeutic program in routine clinical practice. Materials and Methods: 1430 patients (possessing 1430 wAMD eyes) with median age of 78.0 years (71.0, 83.0) were enrolled in a non-randomized, retrospective, observational, multicenter study; 804 (56.2%) eyes were treatment-naïve. Therapy was carried out in accordance with the guidelines of the treatment program (the fixed or pro re nata regimen). Results: After the first year of treatment, there was a gain of 2.03 (12.15) letters; after the second, 0.94 (13.72) (p ˂ 0.001); and after the third, 0.17 (14.05) (p ˂ 0.001). There was a significant reduction in the central retinal thickness. In the first year, the patients received 7.00 (5.00, 8.00) injections. In the following years, a significantly lower number of injections (4.00 (2.00, 5.00)) was administered. After the first year, there was a significant difference in the distribution of the best corrected visual acuity according to the Early Treatment Diabetic Retinopathy Study protocol, with more frequent values in the ranges > 35 ≤ 70 for this parameter and > 70 letters in the treatment naïve eye subgroup. After the first year, central retinal thickness in treatment-naïve eyes was significantly reduced. Conclusions: Regular treatment of wet age-related macular degeneration as part of the treatment program achieves functional stabilization and significant morphological improvement over a long-term, three-year follow-up, with significantly fewer injections needed after the first year of treatment.

DABCO-Customized Nanoemulsions: Characterization, Cell Viability and Genotoxicity in Retinal Pigmented Epithelium and Microglia Cells

Quaternary derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO) and of quinuclidine surfactants were used to develop oil-in-water nanoemulsions with the purpose of selecting the best long-term stable nanoemulsion for the ocular administration of triamcinolone acetonide (TA). The combination of the best physicochemical properties (i.e., mean droplet size, polydispersity index, zeta potential, osmolality, viscoelastic properties, surface tension) was considered, together with the cell viability assays in ARPE-19 and HMC3 cell lines. Surfactants with cationic properties have been used to tailor the nanoemulsions’ surface for site-specific delivery of drugs to the ocular structure for the delivery of TA. They are tailored for the eye because they have cationic properties that interact with the anionic surface of the eye.

A Comparative Study of Ranibizumab and Aflibercept for Neovascular Age-Related Macular Degeneration: 12-Month Outcomes of Polish Therapeutic Program in Non-Tertiary Institution

Introduction This single-center study aimed to compare the 12-month treatment outcomes of ranibizumab with that of aflibercept in routine clinical practice. Methods Cohort of patients diagnosed with treatment-naïve neovascular age-related macular degeneration (AMD), treated using either ranibizumab (n = 33 eyes) or aflibercept (n = 44 eyes) monotherapy over a 12-month follow-up period was analyzed. Anonymous data were extracted from the electronic database dedicated to the drug program. Results In the ranibizumab group, there were no statistically significant changes in best-corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS] letters) and central retina thickness (CRT) (µm), between baseline (67.9 ± 8.6 & 384.9 ± 97.9) and at 12 months (67.9 ± 12.1 & 398.9 ± 127.1; P = 0.372 & P = 0.884, respectively). In the aflibercept, there was an improvement in BCVA and reduction in CRT between baseline (64.2 ± 8.1 & 414.3 ± 97.8) and at 12 months (70.7 ± 7.4 & 342.3 ± 71.6; P < 0.001 & P < 0.001, respectively). There was no difference in BCVA between the two groups at either diagnosis (P = 0.101) or 12 months (P = 0.917). Mean number of injections in the ranibizumab group was significantly lower (4.9 ± 1.5) than in the aflibercept group (6.7 ± 1; P < 0.001). Conclusions  One initial injection of ranibizumab and then pro re nata (PRN) regimen resulted in stabilization of disease progression. Drug selection and treatment scheme could influence twelve-months outcomes. In the aflibercept group, three initial monthly injections and then every two months provided both significant BCVA improvement and CRT reduction at 12 months of treatment.

IL-33trap-mediated IL-33 neutralization does not exacerbate choroidal neovascularization, but fails to protect against retinal degeneration in a dry age-related macular degeneration model

The progressive and sight-threatening disease, age-related macular degeneration (AMD), is a growing public health concern due to ageing demographics, with the highest unmet medical need for the advanced stage of dry AMD, geographic atrophy. The pathogenesis underlying AMD is driven by a complex interplay of genetic and environmental factors. There is ample evidence that inflammation is strongly involved in AMD development. Interleukin-33 (IL-33) has been proposed to be critically involved in retinal degeneration, but a protective role in eye pathophysiology was also demonstrated. The current study investigated the therapeutic potential of IL-33trap, a novel IL-33-neutralizing biologic, in dry AMD/geographic atrophy and, based on controversial data regarding the protective versus detrimental functions of IL-33 in neovascularization, evaluated the risk of progression to wet AMD by IL-33 neutralization. Repeated intravitreal (IVT) injections of IL-33trap in the mouse laser-induced choroidal neovascularization model did not exacerbate neovascularization or leakage, while it significantly inhibited inflammatory cell infiltration in the retinal pigment epithelium and choroid. On the contrary, IVT treatment with IL-33trap significantly induced retinal inflammation and could not prevent retinopathy induction in the mouse sodium iodate (NaIO₃) model. Overall, these data suggest a complex and dichotomous role of IL-33 in eye pathology and indicate that IL-33 neutralization is not able to prevent onset and progression of dry AMD pathogenesis.

Pharmacological inhibition of mitochondrial fission attenuates oxidative stress-induced damage of retinal pigmented epithelial cells

Mitochondria maintain their function by the process of mitochondrial dynamics, which involves repeated fusion and fission. It is thought that the failure of mitochondrial dynamics, especially excessive fission, is related to the progression of several diseases. A previous study demonstrated that mitochondrial fragmentation occurs in the retinal pigmented epithelial (RPE) cells of patients with non-exudative age-related macular degeneration (AMD). We predicted that the suppression of mitochondrial fragmentation offers a novel therapeutic strategy for non-exudative AMD. We investigated whether the inhibition of mitochondrial fission was effective against the oxidative stress-induced damage of ARPE-19 cells. The treatment of ARPE-19 cells with H₂O₂ caused mitochondrial fragmentation, but treatment with mitochondrial division inhibitor 1 (Mdivi-1) suppressed fragmentation. Additionally, Mdivi-1 protected ARPE-19 cells against H₂O₂-induced damage, and suppressed the release of cytochrome c from the mitochondria. Mitochondrial function was evaluated by staining with JC-1 and measuring the production of reactive oxygen species (ROS), which revealed that mitochondrial function improved in the Mdivi-1-treated group. These findings indicated that the inhibition of mitochondrial fission would be a novel therapeutic target for non-exudative AMD.

Emerging innovations in nano-enabled therapy against age-related macular degeneration: A paradigm shift

Age-related macular degeneration (AMD), a degenerative eye disease, is the major cause of irreversible loss of vision among individuals aged 50 and older. Both genetic and environmental factors are responsible for the progressive damage to central vision. It is a multifactorial retinal disease with features such as drusen, hypopigmentation and/or hyperpigmentation of the retinal pigment epithelium, and even choroidal neovascularization in certain patients. AMD is of two major forms: exudative (wet) and atrophic (dry) with changes affecting the macula leading to impaired vision. Although the retina remains an accessible portion for delivering drugs, there are no current options to cure or treat AMD. The existing expensive therapeutics are unable to treat the underlying pathology but display several side effects. However, recent innovations in nanotherapeutics provide an optimal alternative of drug delivery to treat the neovascular condition. These new-age technologies in the nanometer scale would enhance bioactivity and improve the bioavailability of drugs at the site of action to treat AMD. The nanomedicine also provides sustained release of the drug with prolonged retention after penetrating across the ocular tissues. In this review, the insights into the cellular and molecular mechanisms associated with the pathophysiology of AMD are provided. It also serves to review the current progress in nanoparticle-based drug delivery systems that offer feasible treatments in AMD.

Effect of Vitamin D and ω-3 Fatty Acid Supplementation on Risk of Age-Related Macular Degeneration: An Ancillary Study of the VITAL Randomized Clinical Trial

Importance

Observational studies suggest that higher intake or blood levels of vitamin D and marine ω-3 fatty acids may be associated with lower risks of age-related macular degeneration (AMD). However, evidence from randomized trials is limited.

Objective

To evaluate whether daily supplementation with vitamin D3, marine ω-3 fatty acids, or both prevents the development or progression of AMD.

Design, Setting, and Participants

This was a prespecified ancillary study of the Vitamin D and Omega-3 Trial (VITAL), a nationwide, placebo-controlled, 2 × 2 factorial design randomized clinical trial of supplementation with vitamin D and marine ω-3 fatty acids for the primary prevention of cancer and cardiovascular disease. Participants included 25 871 men and women in the US. Randomization was from November 2011 to March 2014, and study pill-taking ended as planned on December 31, 2017.

Interventions

Vitamin D3 (cholecalciferol), 2000 IU per day, and marine ω-3 fatty acids, 1 g per day.

Main Outcomes and Measures

The primary end point was total AMD events, a composite of incident cases of AMD plus cases of progression to advanced AMD among participants with AMD at baseline, based on self-report confirmed by medical record review. Analyses were conducted using the intention-to-treat population.

Results

In total, 25 871 participants with a mean (SD) age of 67.1 (7.0) years were included in the trial. Of them, 50.6% were women, 71.3% were self-declared non-Hispanic White participants, and 20.2% were Black participants. During a median (range) of 5.3 (3.8-6.1) years of treatment and follow-up, 324 participants experienced an AMD event (285 incident AMD and 39 progression to advanced AMD). For vitamin D3, there were 163 events in the treated group and 161 in the placebo group (hazard ratio [HR], 1.02; 95% CI, 0.82-1.27). For ω-3 fatty acids, there were 157 events in the treated group and 167 in the placebo group (HR, 0.94; 95% CI, 0.76-1.17). In analyses of individual components for the primary end point, HRs comparing vitamin D3 groups were 1.09 (95% CI, 0.86-1.37) for incident AMD and 0.63 (95% CI, 0.33-1.21) for AMD progression. For ω-3 fatty acids, HRs were 0.93 (95% CI, 0.73-1.17) for incident AMD and 1.05 (95% CI, 0.56-1.97) for AMD progression.

Conclusion and Relevance

Neither vitamin D3 nor marine ω-3 fatty acid supplementation had a significant overall effect on AMD incidence or progression.

Trial Registration

ClinicalTrials.gov Identifier: NCT01782352.

Disease stability and extended dosing under anti-VEGF treatment of exudative age-related macular degeneration (AMD) - a meta-analysis

PURPOSE

To assess disease stability (absence of intra- and/or subretinal fluid) and the portion of eyes being capable to extend their treatment interval to ≥ 12 weeks in exudative age-related macular degeneration (AMD).

METHODS

A systematic literature search was performed in NCBI, PubMed, CENTRAL, and ClinicalTrials.gov to identify clinical studies reporting treatment outcomes for ranibizumab, aflibercept, and brolucizumab in exudative AMD under a treat-and-extend protocol and a follow-up of ≥ 12 months. Weighted mean differences and subgroup comparisons were used to integrate the different studies.

RESULTS

This meta-analysis refers to 29 published series, including 27 independent samples and 5629 patients. In the pooled group, disease stability was reported in 62.9% and 56.0%, respectively, after 12 and 24 months of treatment, whereas treatment intervals were extended to ≥ 12 weeks in 37.7% and 42.6%, respectively. Ranibizumab, aflibercept, and brolucizumab differed regarding their potential to achieve disease stability (56.3%, 64.5%, and 71.5% after 12, and 50.0%, 52.7% and 75.7% after 24 months; p = < 0.001) and to allow an interval extension to ≥ 12 weeks (28.6%, 34.2%, and 53.3% after 12, and 34.2%, 47.7%, and 41.7% after 24 months; p = < 0.001).

CONCLUSION

The portion of eyes achieving disease stability regressed in the second year, whereas the portion of eyes under a ≥ 12-week interval increased. This discrepancy may reflect the challenges in balancing between under-treatment and a reduced treatment burden.

OPTICAL COHERENCE TOMOGRAPHY BIOMARKERS FOR REDUCTION OF DRUSENOID PIGMENT EPITHELIUM DETACHMENT

PURPOSE

To identify the optical coherence tomography biomarkers that can collectively predict the probability of collapse or reduction of drusenoid pigment epithelium detachment (PED).

METHODS

This consecutive observational case series reviewed the clinical data of 24 eyes with non-neovascular drusenoid PED. Among the study population, 17 eyes showed collapse or reduction of drusenoid PED. The mean follow-up duration was 44.8 ± 24.6 months. Optical coherence tomography-derived parameters were analyzed at baseline, at the last available visit before reduction of PED, at the first available visit after reduction of PED, and at the final visit.

RESULTS

The mean subfoveal choroidal thickness showed a significant decrease after PED reduction and at the most recent visit (P = 0.015). Migration of retinal pigment epithelium cells was detected in 15 (88.2%) after PED reduction; however, there was no significance in the frequency of migration of retinal pigment epithelium cells at each time point (P = 0.392). Non-neovascular subretinal fluid was detected in 7 (41.2%) before PED reduction, 2 (11.8%) after PED reduction, and 2 (11.8%) at the final visit. Interestingly, subretinal fluid appeared more frequently just before reduction of PED (P = 0.029).

CONCLUSION

We found evidence of non-neovascular subretinal fluid and choroidal thinning before reduction in PED. This finding might be useful for detection and prediction of the progression of drusenoid PED.

Influence of unilateral intravitreal bevacizumab injection on the incidence of symptomatic choroidal neovascularization in the fellow eye in patients with neovascular age-related macular degeneration (Review)

Neovascular age-related macular degeneration (neovascular ARMD) represents only 10% of ARMD cases but is responsible, if untreated, for quick and severe central vision loss due to major macular changes. The presence of choroidal neovascularization (CNV) in one eye is associated with an approximately 10% risk of CNV development in the fellow eye each year. Intravitreal anti-VEGF therapy has quickly evolved as the standard treatment in neovascular ARMD in the last decade due to significant anatomical and functional improvements, especially in the early stages. In many reports an improvement in the untreated fellow eye was mentioned and systemic exposure was soon confirmed for all anti-VEGF agents after unilateral intravitreal injection. In particular, bevacizumab intravitreal injection is followed by a consistent reduction of serum VEGF levels and the drug was shown to have the longest serum half-life raising important debates about its safety. Once bevacizumab was detected in the fellow eye of an animal model after unilateral injection, the possible influence on fellow eye conversion rate into neovascular ARMD was questioned. Although comparative studies have not found statistically significant differences between drugs regarding the incidence of symptomatic CNV in the fellow eye during treatment, we observed, on a retrospective 36-month evaluation, a reduced incidence of symptomatic CNV in the fellow eye that might be explained by the consistent systemic exposure of bevacizumab.

Biotechnology and Biomaterial-Based Therapeutic Strategies for Age-Related Macular Degeneration. Part I: Biomaterials-Based Drug Delivery Devices

Age-related Macular Degeneration (AMD) is an up-to-date untreatable chronic neurodegenerative eye disease of multifactorial origin, and the main causes of blindness in over 65 years old people. It is characterized by a slow progression and the presence of a multitude of factors, highlighting those related to diet, genetic heritage and environmental conditions, present throughout each of the stages of the illness. Current therapeutic approaches, mainly consisting of intraocular drug delivery, are only used for symptoms relief and/or to decelerate the progression of the disease. Furthermore, they are overly simplistic and ignore the complexity of the disease and the enormous differences in the symptomatology between patients. Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, the development of biomaterials-based approaches for a personalized and controlled delivery of therapeutic drugs and biomolecules represents the main challenge for the defeat of this neurodegenerative disease. Here we present a critical review of the available and under development AMD therapeutic approaches, from a biomaterials and biotechnological point of view. We highlight benefits and limitations and we forecast forthcoming alternatives based on novel biomaterials and biotechnology methods. In the first part we expose the physiological and clinical aspects of the disease, focusing on the multiple factors that give origin to the disorder and highlighting the contribution of these factors to the triggering of each step of the disease. Then we analyze available and under development biomaterials-based drug-delivery devices (DDD), taking into account the anatomical and functional characteristics of the healthy and ill retinal tissue.

Long-Term Stability of Anti-Vascular Endothelial Growth Factor (a-VEGF) Biologics Under Physiologically Relevant Conditions and Its Impact on the Development of Long-Acting Delivery Systems

The port delivery system with ranibizumab (PDS) is an investigational long-acting drug delivery system for the continuous release of ranibizumab, an anti-VEGF biologic, in the vitreous humor. The efficacy of the PDS implant relies on the maintenance of long-term drug stability under physiological conditions. Herein, the long-term stability of three anti-VEGF biologics - ranibizumab, bevacizumab and aflibercept - was investigated in phosphate buffered saline (PBS) at 37 °C for several months. Comparison of stability profiles shows that bevacizumab and aflibercept are increasingly prone to aggregation whereas ranibizumab undergoes minimal aggregation. Ranibizumab also shows the smallest loss in antigen binding capacity after long-term incubation in PBS. Even though the aggregated forms of bevacizumab and aflibercept bind to VEGF, the consequences of aggregation on immunogenicity, implant function and efficacy are unknown. These results highlight the importance of maintaining long-term drug stability under physiologically relevant conditions which is necessary for achieving efficacy with an in vivo continuous drug delivery device such as the PDS implant.

An Endostatin-lentivirus (ES-LV)-EPC gene therapy agent for suppression of neovascularization in oxygen-induced retinopathy rat model

BACKGROUND

Transplantation of gene transfected endothelial progenitor cells (EPCs) has provided novel methods for tumor neovascularization therapy but not for ocular disease therapy. This study aimed to investigate the efficacy of endostatin transfected EPCs in retinal neovascularization therapy.

RESULTS

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) showed the high expression of endostatin in endostatin-lentivirus-EPCs. The neovascularization leakage area and the number of preretinal neovascular cell nuclei were significantly decreased in the endostatin-lentivirus and endostatin-lentivirus-EPC groups, and the effects of these two treatments on inhibiting retinal neovascularization were almost the same. These two groups also showed the greater retinal distribution of endostatin. Intravitreal injections of endostatin-lentivirus-EPCs inhibited retinal neovascularization, vascular endothelial growth factor (VEGF) and CD31 expression, and increased endostatin expression in vivo. Endostatin-lentivirus-EPCs targeted and prevented pathologic retinal neovascularization.

CONCLUSIONS

Gene-combined EPCs represent a potential new therapeutic agent for the treatment of neovascular eye diseases.

Intravitreal enzyme replacement preserves retinal structure and function in canine CLN2 neuronal ceroid lipofuscinosis

CLN2 neuronal ceroid lipofuscinosis is a hereditary neurodegenerative disorder characterized by progressive vision loss, neurological decline, and seizures. CLN2 disease results from mutations in TPP1 that encodes the lysosomal enzyme tripeptidyl peptidase-1 (TPP1). Children with CLN2 neuronal ceroid lipofuscinosis experience ocular disease, characterized by progressive retinal degeneration associated with impaired retinal function and gradual vision loss culminating in total blindness. A similar progressive loss of retinal function is also observed in a dog CLN2 model with a TPP1 null mutation. A study was conducted to evaluate the efficacy of periodic intravitreal injections of recombinant human (rh) TPP1 in inhibiting retinal degeneration and preserving retinal function in the canine model. TPP1 null dogs received periodic intravitreal injections of rhTPP1 in one eye and vehicle in the other eye beginning at approximately 12 weeks of age. Ophthalmic exams, in vivo ocular imaging, and electroretinography (ERG) were repeated regularly to monitor retinal structure and function. Retinal histology was evaluated in eyes collected from these dogs when they were euthanized at end-stage neurological disease (43-46 weeks of age). Intravitreal rhTPP1 dosing prevented disease-related declines in ERG amplitudes in the TPP1-treated eyes. At end-stage neurologic disease, TPP1-treated eyes retained normal morphology while the contralateral vehicle-treated eyes exhibited loss of inner retinal neurons and photoreceptor disorganization typical of CLN2 disease. The treatment also prevented the development of disease-related focal retinal detachments observed in the control eyes. Uveitis occurred secondary to the administration of the rhTPP1 but did not hinder the therapeutic benefits. These findings demonstrate that periodic intravitreal injection of rhTPP1 preserves retinal structure and function in canine CLN2 disease.

NEI-Supported Age-Related Macular Degeneration Research: Past, Present, and Future

Purpose

To review past and current National Eye Institute (NEI)–supported age-related macular degeneration (AMD) activities and initiatives and preview upcoming coordinated efforts for studying AMD.

Methods

We conducted and summarized a portfolio analysis and literature review of NEI intramural and extramural AMD activities.

Results

The NEI supports a broad range of AMD research, both by individual independent investigators as well as through networks and consortia. The International AMD Genomics Consortium, Age-Related Eye Disease Study, Age-Related Eye Disease Study 2 (AREDS2), and Comparison of AMD Treatments Trial legacy work probed the complex genetics, clinical presentation, and standards of patient care, respectively. The NEI AMD Pathobiology Working Group identified gaps and opportunities for future research efforts. The AMD Ryan Initiative Study and clinical trials testing the efficacies of minocycline to modulate retinal microglia activity and induced pluripotent stem cells–derived retinal pigmented epithelium (RPE) patch implants to rescue photoreceptor cell death are among the future directions for NEI-supported AMD research. Finally, NEI commissioned the creation of AREDS2 participant-derived induced pluripotent stem cell (iPSC) lines linked to their associated genomic and phenotypic datasets. These datasets will also be linked to the data obtained using their associated iPSC-derived cells (RPE, retina, choroid) and made publicly available.

Conclusions

Investments by NEI for AMD research will continue to provide invaluable resources to investigators committed to addressing this complex blinding disease and other retinal degenerative diseases.

Translational Relevance

NEI now stands poised to expand the resources available to clinical investigators to uncover disease mechanisms and move experimental therapies into clinical trials.

One-year outcomes of the Polish treatment program for the wet form of age-related macular degeneration using intravitreal therapy

PURPOSE

To report 12-month outcomes of a Polish National Treatment Program using aflibercept and ranibizumab in eyes with wet, age-related macular degeneration in routine clinical practice.

MATERIAL AND METHODS

This was a non-randomized, retrospective, observational multicenter study. Anonymous data contained in the electronic Therapeutic Program Monitoring System were utilized in this study.

RESULTS

The study population consisted of 2828 eyes from 2718 patients. The median age was 76.0 [70.0, 81.0] years; 61.7% were female. Best corrected visual acuity increased from 58.86 [50.05, 69.95] letters to 65.1 [50.1, 73.9] letters (p < 0.001). The median change in best corrected visual acuity was 0.0 [-4.0, 12.2] letters: 2.9 [-2.9, 15.1] letters for treatment-naïve eyes and 0.0 [-4.0, 8.8] letters for those continuing treatment (p < 0.001). The median central retinal thickness was significantly reduced from 341.0 [281.0, 422.0] to 275.0 [221.0, 344.0] μm (p < 0.001). The median number of visits was 9.0 [8.0, 9.0]. The median number of injections was 7.0 [6.0, 8.0]: 8.0 [7.0, 8.0] for treatment-naïve eyes and 6.0 [5.0, 7.0] for those continuing treatment (p < 0.001).

CONCLUSION

Eyes treated as part of the Polish therapeutic program gained functional stability and morphological improvement. Treatment-naïve eyes showed the greatest functional benefit.

Photophysics of J-Aggregating Porphyrin-Lipid Photosensitizers in Liposomes: Impact of Lipid Saturation

Porphyrin aggregates have attractive photophysical properties for phototherapy and optical imaging, including quenched photosensitization, efficient photothermal conversion, and unique absorption spectra. Although hydrophobic porphyrin photosensitizers have long been encapsulated into liposomes for drug delivery, little is known about the membrane properties of liposomes with large amphiphilic porphyrin compositions. In this paper, a porphyrin-lipid conjugate was incorporated into liposomes formed of saturated or unsaturated lipids to study the membrane composition-dependent formation of highly ordered porphyrin J-aggregates and disordered aggregates. Porphyrin-lipid readily phase-separates in saturated membranes, forming J-aggregates that are destabilized during the ripple phase below the main thermal transition. Porphyrin-lipid J-aggregates are photostable with a photothermal efficiency of 54 ± 6%, comparable to gold. Even at high porphyrin-lipid compositions, porphyrin J-aggregates coexist with a minority population of disordered aggregates, which are photodynamically active despite being fluorescently quenched. For photothermal applications, liposome formulations that encourage porphyrin-lipid phase separation should be explored for maximum J-aggregation.

Single Cell Analysis in Vascular Biology

The ability to quantify DNA, RNA, and protein variations at the single cell level has revolutionized our understanding of cellular heterogeneity within tissues. Via such analyses, individual cells within populations previously thought to be homogeneous can now be delineated into specific subpopulations expressing unique sets of genes, enabling specialized functions. In vascular biology, studies using single cell RNA sequencing have revealed extensive heterogeneity among endothelial and mural cells even within the same vessel, key intermediate cell types that arise during blood and lymphatic vessel development, and cell-type specific responses to disease. Thus, emerging new single cell analysis techniques are enabling vascular biologists to elucidate mechanisms of vascular development, homeostasis, and disease that were previously not possible. In this review, we will provide an overview of single cell analysis methods and highlight recent advances in vascular biology made possible through single cell RNA sequencing.

Cell-based approaches towards treating age-related macular degeneration

Age-related macular degeneration as one of the most common causes of worldwide vision loss needs a proper approach for treatment. Therein, cell therapy and regenerative medicine can hold a great promise to be an effective approach. Accordingly, some preclinical and clinical studies were conducted to search around the therapeutic influence of stem cells in Age-related macular degeneration models and subjects. Hereupon, the purpose of the current review is to discuss the mechanisms of age-related macular degeneration, appropriate animal models along with suitable dosage and route of stem cell administration for its treatment.

Adding a Corticosteroid or Switching to Another Anti-VEGF in Insufficiently Responsive Wet Age-Related Macular Degeneration

Purpose

To compare the effect of adding a corticosteroid or switching to another anti-VEGF treatment in patients with exudative age-related macular degeneration (eAMD) with persisting intraretinal fluid on anti-VEGF monotherapy.

Methods

This retrospective, interventional case series involved 43 pseudophakic eyes with eAMD and persistent intraretinal fluid on anti-VEGF treatment that switched treatment to a combination of Ozurdex^® or Triamcinolone and anti-VEGF therapy (group 1) or to another anti-VEGF agent (group 2). The number of injections, time to re-injection, change in central retinal thickness (CRT), and best-corrected visual acuity (BCVA) from 12 months prior to 12 months after switch to third-line therapy were defined as primary outcomes.

Results

Whereas the treatment demand was reduced (from 8.8±2.2 to 4.6±2.9 injections; p=0.001) and the re-injection interval extended in group 1 (from 1.5±0.4 months to 4.4±3.8 months; p=0.001), these parameters did not change in group 2 (7.4±1.6 to 7.3±2.2; p=0.90 and 1.7±0.3 months to 1.9±0.8 months; p=0.75). Mean CRT decreased from 455.7±30.1 and 427.6±36.0µm (groups 1 and 2, respectively) to 359.1±38.2 and 303.1±44.4µm (intergroup p=0.03). The mean baseline BCVA of 62.6±3.8 letters (group 1) and 63.0±1.9 letters (group 2) remained stable under therapy in both groups (intergroup p=0.67).

Conclusion

In eyes with eAMD with persistent intraretinal fluid on anti-VEGF monotherapy despite frequent re-injections, corticosteroids achieved a similar functional and morphological outcome over 12 months as switching to another anti-VEGF therapy, but with a reduced injection burden. In selected cases, corticosteroid treatment may thus be an option for third-line therapy in refractory exudative AMD.

PU-91 drug rescues human age-related macular degeneration RPE cells; implications for AMD therapeutics

Since mitochondrial dysfunction is implicated in the pathogenesis of AMD, this study is based on the premise that repurposing of mitochondria-stabilizing FDA-approved drugs such as PU-91, might rescue AMD RPE cells from AMD mitochondria-induced damage. The PU-91 drug upregulates PGC-1α which is a critical regulator of mitochondrial biogenesis. Herein, we tested the therapeutic potential of PU-91 drug and examined the additive effects of treatment with PU-91 and esterase inhibitors i.e., EI-12 and EI-78, using the in vitro transmitochondrial AMD cell model. This model was created by fusing platelets obtained from AMD patients with Rho⁰ i.e., mitochondria-deficient, ARPE-19 cell lines. The resulting AMD RPE cell lines have identical nuclei but differ in their mitochondrial DNA content, which is derived from individual AMD patients. Briefly, we report significant improvement in cell survival, mitochondrial health, and antioxidant potential in PU-91-treated AMD RPE cells compared to their untreated counterparts. In conclusion, this study identifies PU 91 as a therapeutic candidate drug for AMD and repurposing of PU-91 will be a smoother transition from lab bench to clinic since the pharmacological profiles of PU-91 have been examined already.

Diagnostic accuracy of optical coherence tomography angiography for choroidal neovascularization: a systematic review and meta-analysis

BACKGROUND

Optical coherence tomography angiography (OCTA), an innovative image technique, renders visualization of ocular neovascularization through non-invasive means, which has been applied in recent years. Therefore, the present study was designed to assess the diagnostic value of OCTA in detecting the choroidal neovascularization (CNV).

METHODS

In brief, PubMed, Web of Science and Cochrane Library databases were systematically searched from January 2014 to June 2019. Afterwards, a meta-analysis was performed to determine the pooled diagnostic accuracy in a random-effects model using STATA 15.1 and Meta-Disc 1.4 software. Quality Assessment of diagnostic Accuracy Version 2 was used to evaluate the risk of bias of each study by Revman 5.3 software. In addition, a meta-regression model was further conducted to explore potential sources of heterogeneity.

RESULTS

According to pre-set inclusion and exclusion criteria, 16 eligible studies were enrolled in this study. A total of 447 CNV eyes and 414 non-CNV eyes were included to investigate the diagnostic accuracy of OCTA. As a result, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (PLR), diagnostic odds ratio (DOR) and the area under the summary receiver operating characteristic curve (sROC-AUC) were 0.87 (95% CI 0.81-0.92), 0.97 (95% CI 0.92-0.99), 32.7 (95% CI 10.1-105.5), 0.13 (95% CI 0.08-0.20), 252 (95% CI 63-1011) and 0.96 (95% CI 0.94-0.97), respectively.

CONCLUSIONS

In summary, we demonstrated that OCTA was of high diagnostic value for detecting intraocular CNV.

Light stress affects cones and horizontal cells via rhodopsin-mediated mechanisms

Retinal degenerations are a major cause of blindness in human patients. The identification of endogenous mechanisms involved in neurodegeneration or neuroprotection helps to understand the response of the retina to stress and provides essential information not only for basic retinal physiology but also for defining molecular targets for neuroprotective strategies. Here we used excessive light exposure as a model system to study mechanisms of photoreceptor degeneration in mice. Using one wild type and four genetically modified mouse strains, we demonstrate that light exposure resulted not only in the degeneration of rods but also in an early but transient repression of several cone-specific genes, in a reversible hyperreflectivity of the outer retina including the outer plexiform layer, and in the loss of horizontal cells. The effects on cones, horizontal cells and the inner retina depended on light absorption by rhodopsin and, at least partially, on leukemia inhibitory factor. This demonstrates the existence of intercellular communication routes that transduce rod stress to other cells, likely to provide support for photoreceptors and increase cell survival in the injured retina.

Safety and tolerability of ranibizumab in uni/bilateral neovascular age-related macular degeneration: 12-month TWEYEs study

Background

To evaluate the safety and tolerability of ranibizumab 0.5 mg in patients with uni/bilateral neovascular age-related macular degeneration (nAMD) and best-corrected visual acuity (BCVA)<2/10 and/or second eye affected, regardless of BCVA.

Methods

In this 12-month, prospective, multicentre, open-label, single arm, pragmatic interventional study, patients (N=941) aged ≥ 50 years were to receive ranibizumab as per approved label, monthly until maximum stable visual acuity (VA) was achieved (initially, three or more injections may be required). Thereafter, patients were to be monitored monthly for VA and treatment was to be resumed if VA was reduced due to disease activity.

Results

Of the 936 patients treated with ranibizumab at least once during the study, 823/113 were unilaterally/bilaterally (not simultaneously) treated. The mean (SD) number of ranibizumab injections during the study was 5.4 (2.9)/10.6 (5.0) injections in uni/bilaterally treated patients. Three systemic drug-related adverse events (AEs) (all serious, all in unilaterally treated patients) and 18 systemic AE of special interest (AESIs) (11 serious, 16/2 in unilaterally/bilaterally treated patients) occurred during the study. The annual incidence rate (AIR) (events/1000 person-years) for systemic drug-related AEs, considering a 15-day/30-day risk period, 11.0/8.5 for unilaterally treated patients. Considering the same risk period, the AIR (events/1000 person-years) for systemic AESIs for unilaterally treated patients was 22.1/19.9. Considering a 30-day risk period, the AIR (events/1000 treated eye-years) of ocular drug-related AEs was 23 and AESIs was 11.5.

Conclusions

The low incidence of AEs and AESIs demonstrated the good safety and tolerability of ranibizumab in unilaterally/bilaterally treated patients with nAMD in this real-world setting.

Bioanalytical challenges and unique considerations to support pharmacokinetic characterization of bispecific biotherapeutics

Compared with conventional (monospecific) therapeutics, bispecific protein therapeutics present unique challenges for pharmacokinetic (PK) characterization – namely, the characterization of multiple functional domains as well as the consideration of biotransformation or interference by the formation of antitherapeutic antibodies against each functional domain. PK characterization is essential to the success of the overall drug development plan and for molecules with multiple binding domains; multiple bioanalytical methods may be needed to answer critical questions for each phase of drug development. The number of bispecific protein therapeutics entering drug development continues to increase, and therefore, a bioanalytical strategy for the PK characterization of bispecific molecules and study of their in vivo structure–function relationship is needed. This review presents case studies and a regulatory perspective.

Nanodelivery of doxorubicin for age-related macular degeneration

OBJECTIVE

Polymeric nanoparticles (NPs) containing doxorubicin (DOX) were prepared for the inhibition of hypoxia-induced factor 1α (HIF-1α).

SIGNIFICANCE

HIF-1α is responsible for the upregulation of several angiogenic factors, including vascular endothelial growth factor (VEGF). DOX inhibits HIF-1α but is highly toxic. By encapsulating DOX in NPs, drug delivery will be sustained and toxicity will be reduced without limiting efficacy.

METHODS

DOX NPs were prepared using both polylactic coglycolic acid (PLGA) and chitosan. PLGA NPs were prepared via nanoprecipitation (NPC) and single and double emulsion diffusion (SE; DE). Chitosan NPs were formulated using ionic gelation (IG), and complex coacervation (CC). Size, polydispersity index (PDI), and zeta potential (ZP) were determined via dynamic light scattering (DLS) (n = 3). The encapsulation efficiency (EE), drug loading capacity (DLC) (n = 3) and in vitro drug release profiles (IVR) at 37 °C (n = 4) were analyzed via spectroscopy at 480 nm (λ_max). The cytotoxicity of each formulation as well as free DOX solution in ARPE-19 cells was determined via MTT assay after 24 h (n = 3). HIF-1α and VEGF inhibition in ARPE-19 cells were measured via ELISA (n = 3).

RESULTS

The results were consistent with the hypothesis; the NP formulations decreased HIF-1α and VEGF-A expression in ARPE-19 cells with reduced cytotoxicity. SE, DE, and CC demonstrated low ZP as well as the most rapid drug release of the tested formulations. FTIR confirmed the presence of DOX on the SE NP surface, indicating instability.

CONCLUSIONS

SE, DE, and CC destabilized. NPC was the most efficient formulation for the nanodelivery of DOX for AMD.

Long-acting intraocular Delivery strategies for biological therapy of age-related macular degeneration

As one of the leading causes of central vision loss in elderly population, worldwide cases of age-related macular degeneration (AMD) have seen a dramatic increase over the past several years. Treatment regimens for AMD, especially with biological agents, are complicated due to anatomical and physiological barriers, as well as administration of high doses and frequent regimens. Some clinical examples include monthly intravitreal administration of anti-VEGF antibody ranibizumab (Lucentis®) from Genentech and aflibercept (Eylea®) from Regeneron Pharmaceuticals. Long-acting sustained intraocular drug delivery provides promising solutions, such as Vitrasert® from Bausch & Lomb, an intravitreal biodegradable polymeric implant made from poly(D,L-lactic co glycolic acid) (PLGA), and can be used as a guiding reference to formulate sustained delivery systems. In this review, we discuss the anatomy and physiology of the eye, barriers to delivery, pathology of AMD, opportunities for biological therapeutics, and future prospects of intraocular delivery strategies that are in development for treatment of AMD.

Strategies for modifying drug residence time and ocular bioavailability to decrease treatment frequency for back of the eye diseases

INTRODUCTION

Treating posterior eye diseases has become a major area of focus for pharmaceutical and biotechnology companies. Current standard of care for treating posterior eye diseases relies on administration via intravitreal injection. Although effective, this is not without complications and there is great incentive to develop longer-acting therapeutics and/or sustained release delivery systems. Here, we present an overview of emerging technologies for delivery of biologics to the back of the eye.

AREAS COVERED

Posterior eye diseases, intravitreal injection, age-related macular degeneration, anti-VEGF, ocular pharmacokinetics, novel technologies to extend half-life, in vivo models, translation to the clinic, and hurdles to effective patient care.

EXPERT OPINION

Posterior eye diseases are a worldwide public health issue. Although anti-VEGF molecules represent a major advance for treating diseases involving choroidal neovascularization, frequent injection can be burdensome for patients and clinicians. There is a need for effective and patient-friendly treatments for posterior eye diseases. Many technologies that enable long-acting delivery to the back of the eye are being evaluated. However, successful development of novel therapies and delivery technologies is hampered by a multitude of factors, including patient education, translatability of in vitro/in vivo preclinical data to the clinic, and regulatory challenges associated with novel technologies.

The Question of a Role for Statins in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of irreversible central vision loss in patients over the age of 65 years in industrialized countries. Epidemiologic studies suggest that high dietary fat intake is a risk factor for the development and progression of both vascular and retinal disease. These, and other associations, suggest a hypothesis linking elevated cholesterol and AMD progression. It follows, therefore, that cholesterol-lowering medications, such as statins, may influence the onset and progression of AMD. However, the findings have been inconclusive as to whether statins play a role in AMD. Due to the significant public health implications of a potential inhibitory effect of statins on the onset and progression of AMD, it is important to continually evaluate emerging findings germane to this question.

Effect of Phacoemulsification on Visual Acuity and Macular Morphology in Patients with Wet Age-Related Macular Degeneration

Background

This article discusses the effectiveness of phacoemulsification cataract surgery with intraocular lens implantation in patients with wet age-related macular degeneration in the inactive phase of the disease.

Material/Methods

Forty-nine patients (50 eyes) aged 78.94±5.54 years, previously treated with intravitreal injections of anti-vascular endothelial growth factor agents, were qualified for a prospective, randomized 12-month study. The participants were divided into 2 groups. Group I consisted of 25 patients (25 eyes) who were subjected to phacoemulsification cataract surgery. Group II consisted of 24 patients (25 eyes) who were not subjected to phacoemulsification cataract surgery despite having a lens opacity of grade II or higher according to the Lens Opacities Classification System.

Results

After 12 months of follow-up, patients in group I gained on average 8.04 letters (p<0.001). Furthermore, 20% of the eyes had a significant improvement in best corrected visual acuity of ≥15 Early Treatment of Diabetic Retinopathy Study Chart letters. Patients in group II lost on average 1.96 letters (p>0.05). No significant differences between central retinal thickness values in either group (p>0.05) were noted. The mean number of intravitreal injections of anti-vascular endothelial growth factor agents during the study was 2.64±1.98 in group I and 2.92±2.40 in group II (p>0.05).

Conclusions

Phacoemulsification performed in eyes with wet age-related macular degeneration during the inactive phase of the disease significantly improves visual acuity. In addition, it does not significantly influence the frequency of intravitreal injections of anti-vascular endothelial growth factor agents or disease activity.

Human embryonic stem cell-derived retinal pigment epithelium transplants as a potential treatment for wet age-related macular degeneration

Stem cell therapy may provide a safe and promising treatment for retinal diseases. Wet age-related macular degeneration (wet-AMD) is a leading cause of blindness in China. We developed a clinical-grade human embryonic stem cell (hESC) line, Q-CTS-hESC-2, under xeno-free conditions that differentiated into retinal pigment epithelial cells (Q-CTS-hESC-2-RPE). A clinical trial with three wet-AMD patients was initiated in order to study the safety and tolerance to Q-CTS-hESC-2-RPE cell transplants. The choroidal neovascularization membrane was removed and then a suspension of 1 × 10⁶ Q-CTS-hESC-2-RPE cells were injected into a subfoveal pocket. The patients were followed for 12 months during which no adverse effects resulting from the transplant were observed. Anatomical evidence suggested the existence of new RPE-like cell layer in the previously damaged area. Visual and physiological testing indicated limited functional improvement, albeit to different degrees between patients. This study provides some promising early results concerning the use of transplanted hESC-RPE cells to alleviate wet-AMD.

Cell-specific gene therapy driven by an optimized hypoxia-regulated vector reduces choroidal neovascularization

Aberrant growth of blood vessels in the choroid layer of the eye, termed choroidal neovascularization (CNV), is the pathological hallmark of exudative age-related macular degeneration (AMD), causing irreversible blindness among the elderly. Co-localization of proangiogenic factors and hypoxia inducible factors (HIF) in neovascular membranes from AMD eyes suggests the role of hypoxia in pathogenesis of CNV. In order to utilize hypoxic conditions in RPE for therapeutic purposes, we developed an optimized hypoxia regulated, RPE cell-specific gene therapy to inhibit choroidal neovascularization. An adeno-associated virus (AAV2) vector comprising a RPE-specific promoter and HIF-1 response elements (HRE) was designed to regulate production of human endostatin (a powerful angiostatic protein) in RPE. The vector was tested in a mouse model of laser-induced CNV using subretinal delivery. Spectral domain optical coherence tomography (SD-OCT) images from live mice and confocal images from lectin stained RPE flat mount sections demonstrated reduction in CNV areas by 80% compared to untreated eyes. Quantitative real-time polymerase chain reaction (qPCR) confirmed exogenous endostatin mRNA expression from the regulated vector that was significantly elevated 3, 7, and 14 days following laser treatment, but its expression was completely shut off after 45 days. Thus, RPE-specific, hypoxia-regulated delivery of anti-angiogenic proteins could be a valuable therapeutic approach to treat neovascular AMD at the time and in the ocular space where it arises.

KEY POINTS

An optimized gene therapy vector targeting hypoxia and tissue-specific expression has been designed. The inhibitory role of gene therapy vector was tested in a mouse model of laser-induced CNV. An 80% reduction in choroidal neovascularization was achieved by the optimized vector. The expression of endostatin was limited to retinal pigment epithelium and regulated by hypoxia.

Association of Genetic Variants With Response to Anti-Vascular Endothelial Growth Factor Therapy in Age-Related Macular Degeneration

Importance

Visual acuity (VA) outcomes differ considerably among patients with neovascular age-related macular degeneration (nAMD) treated with anti-vascular endothelial growth factor (VEGF) drugs. Identification of pharmacogenetic associations may help clinicians understand the mechanisms underlying this variability as well as pave the way for personalized treatment in nAMD.

Objective

To identify genetic factors associated with variability in the response to anti-VEGF therapy for patients with nAMD.

Design, Setting, and Participants

In this multicenter genome-wide association study, 678 patients with nAMD with genome-wide genotyping data were included in the discovery phase; 1380 additional patients with nAMD were genotyped for selected common variants in the replication phase. All participants received 3 monthly injections of bevacizumab or ranibizumab. Clinical data were evaluated for inclusion/exclusion criteria from October 2014 to October 2015, followed by data analysis from October 2015 to February 2016. For replication cohort genotyping, clinical data collection and analysis (including meta-analysis) was performed from March 2016 to April 2017.

Main Outcomes and Measures

Change in VA after the loading dose of 3 monthly anti-VEGF injections compared with baseline.

Results

Of the 2058 included patients, 1210 (58.8%) were women, and the mean (SD) age across all cohorts was 78 (7.4) years. Patients included in the discovery cohort and most of the patients in the replication cohorts were of European descent. The mean (SD) baseline VA was 51.3 (20.3) Early Treatment Diabetic Retinopathy Study (ETDRS) score letters, and the mean (SD) change in VA after the loading dose of 3 monthly injections was a gain of 5.1 (13.9) ETDRS score letters (ie, 1-line gain). Genome-wide single-variant analyses of common variants revealed 5 independent loci that reached a P value less than 10 × 10-5. After replication and meta-analysis of the lead variants, rs12138564 located in the CCT3 gene remained nominally associated with a better treatment outcome (ETDRS letter gain, 1.7; β, 0.034; SE, 0.008; P = 1.38 × 10-5). Genome-wide gene-based optimal unified sequence kernel association test of rare variants showed genome-wide significant associations for the C10orf88 (P = 4.22 × 10-7) and UNC93B1 (P = 6.09 × 10-7) genes, in both cases leading to a worse treatment outcome. Patients carrying rare variants in the C10orf88 and UNC93B1 genes lost a mean (SD) VA of 30.6 (17.4) ETDRS score letters (ie, loss of 6.09 lines) and 26.5 (13.8) ETDRS score letters (ie, loss of 5.29 lines), respectively, after 3 months of anti-VEGF treatment.

Conclusions and Relevance

We propose that there is a limited contribution of common genetic variants to variability in nAMD treatment response. Our results suggest that rare protein-altering variants in the C10orf88 and UNC93B1 genes are associated with a worse response to anti-VEGF therapy in patients with nAMD, but these results require further validation in other cohorts.

Therapeutic potential of staphylococcal superantigen-like protein 7 for complement-mediated hemolysis

Previous studies have demonstrated that staphylococcal superantigen-like protein 7 (SSL7), a protein produced by Staphylococcus aureus, potently inhibits the formation of the complement membrane attack complex by binding to complement component 5 (C5). However, because of the predicted immunogenicity of SSL7 as a foreign protein in humans, its potential as a new complement inhibitor for treating complement-mediated diseases is uncertain. In this study, we found that administration of SSL7 significantly prevented complement-mediated hemolysis and reduced hemoglobinuria in a mouse model of complement-mediated intravascular hemolysis. Interestingly, although repetitive administrations of SSL7 elicited anti-SSL7 antibody production, administration of SSL7 at a dose of 2 μg/mouse was still able to significantly attenuate complement-mediated intravascular hemolysis in vivo in the presence of the antibodies. In addition, even though anti-SSL7 antibodies were detectable in normal human donors, these antibodies did not significantly reduce the complement inhibitory activity of SSL7 in in vitro assays. Finally, inoculation of SSL7 in the anterior chamber of the eye suppressed the production of SSL7-reactive antibodies after repetitive SSL7 administration. These results suggest that SSL7 could be developed as an economical alternative to the existing C5-targeted drug, eculizumab, especially for controlling acute complement activation in catastrophic conditions such as drug-induced immune hemolytic anemia and ABO-incompatible erythrocyte transfusions. These data also suggest that approaches such as anterior chamber-associated immune deviation could be employed to establish an antigen-specific immune tolerance for long-term SSL7 administration.

KEY MESSAGES

• SSL7 functions in the presence of anti-SSL7 antibodies both in vitro and in vivo. • SSL7 has the potential to be developed as a new and economical complement inhibitor for treating complement-mediated hemolysis.

New Therapies of Neovascular AMD-Beyond Anti-VEGFs

Neovascular age-related macular degeneration (nAMD) is one of the leading causes of blindness among the aging population. The current treatment options for nAMD include intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF). However, standardized frequent administration of anti-VEGF injections only improves vision in approximately 30–40% of nAMD patients. Current therapies targeting nAMD pose a significant risk of retinal fibrosis and geographic atrophy (GA) development in nAMD patients. A need exists to develop new therapies to treat nAMD with effective and long-term anti-angiogenic effects. Recent research on nAMD has identified novel therapeutic targets and angiogenic signaling mechanisms involved in its pathogenesis. For example, tissue factor, human intravenous immune globulin, interferon-β signaling, cyclooxygenase-2 (COX-2) and cytochrome P450 monooxygenase lipid metabolites have been identified as key players in the development of angiogenesis in AMD disease models. Furthermore, novel therapies such as NACHT, LRR and PYD domains containing protein 3 (NLRP3) inflammasome inhibition, inhibitors of integrins and tissue factor are currently being tested at the level of clinical trials to treat nAMD. The aim of this review is to discuss the scope for alternative therapies proposed as anti-VEGFs for the treatment of nAMD.

Therapeutic Effect of Anti-VEGF for Age-Related Macular Degeneration in the Untreated Fellow Eye

Intravitreal injections of antivascular endothelial growth factor (anti-VEGF) agents have been reported to occasionally produce a therapeutic effect in the uninjected fellow eye. Here, three patients with bilateral neovascular age-related macular degeneration are presented. In all three patients, unilateral anti-VEGF injection resulted in bilateral reduction of macular thickness as measured by spectral domain optical coherence tomography.