Therapies for neovascular age-related macular degeneration: current approaches and pharmacologic agents in development

A Sojourn on Liposomal Delivery System: Recent Advances and Future Prospects

Liposomes are unique novel drug delivery carriers that favor the effective transportation of pharmaceuticals. These vesicles acquire one or more phospholipid bilayer membranes, and an inner aqueous core can carry both aqueous and lipid drugs. While hydrophilic molecules can be confined in the aqueous core, hydrophobic molecules are injected into the bilayer membrane. Liposomes have many benefits as a drug delivery method, including biocompatibility, the capacity to carry large drug payloads, and a variety of physicochemical and biological parameters that can be altered to influence their biological characteristics. In addition, being a size of 10-100 nm range can have numerous additional benefits, including enhanced pharmacokinetics, clever escape from the reticuloendothelial system, greater in vivo stability, longer and site-specific administration, and increased internalization in tumor tissue (enhanced permeability and retention impact). The current review focuses on the structural composition of liposomes, formulation technologies, and suitable case studies for optimizing biopharmaceutical performance. Moreover, clinical trials and marketed formulations of liposomes have been also stated in the prior art.

Angiogenic footprints in diabetic retinopathy: opportunities for drug development

Diabetic retinopathy is one of the withering disorders that has been making the lives of patients miserable. Arising as a result of chronic high blood sugar levels in diabetes patients, retinopathy has become a major reason causing permanent blindness, retinal detachment, vitreous humor, rage, or glaucoma among patients. Angiogenesis being the major culprit behind the development of this condition is the growth of new blood vessels from the earlier ones existing. The abnormal growth and poor development of blood vessels also lead to aggravation of the conditions, with vascular endothelial growth factor (VEGF) playing a major role in the process. Various anti-angiogenic therapies or anti-VEGF therapies are being explored for the treatment of this condition. 4 widely explored drugs being-Bevacizumab, pegaptanib sodium, ranibizumab, and aflibercept. The review article tries to summarize studies illustrating the efficacy of these drugs in the treatment of diabetic retinopathy along with some of the herbal therapeutic paradigms displaying anti-angiogenic action that is being used to treat this condition.

Human Umbilical Tissue-Derived Cells Secrete Soluble VEGFR1 and Inhibit Choroidal Neovascularization

Exudative age-related macular degeneration (AMD), characterized by choroidal neovascularization (CNV), is the leading cause of irreversible blindness in developed countries. Anti-vascular endothelial growth factor (VEGF) drugs are the standard treatment for AMD, but they have limitations. Cell therapy is a promising approach for ocular diseases, and it is being developed in the clinic for the treatment of retinal degeneration, including AMD. We previously showed that subretinal injection of human umbilical tissue-derived cells (hUTCs) in a rodent model of retinal degeneration preserved photoreceptors and visual function through rescue of retinal pigment epithelial (RPE) cell phagocytosis. Here we investigated the effect of hUTCs on a rat model of laser-induced CNV and on a human RPE cell line, ARPE-19, for VEGF production. We demonstrate that subretinal injection of hUTCs significantly inhibited CNV and lowered choroidal VEGF in vivo. VEGF release from ARPE-19 decreased when co-cultured with hUTCs. Soluble VEGF receptor 1 (sVEGFR1) is identified as the only factor in hUTC conditioned medium (CM) that binds to VEGF. The level of exogenous recombinant VEGF in hUTC CM was dramatically reduced and could be recovered with sVEGFR1-neutralizing antibody. This suggests that hUTC inhibits angiogenesis through the secretion of sVEGFR1 and could serve as a novel treatment for angiogenic ocular diseases, including AMD.

How Successful is Switching from Bevacizumab or Ranibizumab to Aflibercept in Age-Related Macular Degeneration? A Systematic Overview

Emerging anti-vascular endothelial growth factor (anti-VEGF) therapies for neovascular age-related macular degeneration (nAMD) have revolutionised medical retina practice and the management and eventual outcome of nAMD. Recent research has focused on evaluating and comparing the efficacy of the two most widely employed anti-VEGF agents, bevacizumab and ranibizumab; however, a subgroup of patients with nAMD demonstrates a suboptimal response to standard therapy. We have therefore conducted a review of pertinent studies published until August 2018 which have documented the clinical efficacy when switching to a different anti-VEGF. Evidence on baseline disease characteristics, injection frequency and disease outcome has been obtained for patients treated with ranibizumab 0.5 mg and/or bevacizumab 1.25 mg and were switched to aflibercept 2 mg. Our review identified 45 studies investigating switching to aflibercept. Our review showed a clear anatomical benefit after the switch in terms of central retinal thickness and pigment epithelium detachment characteristics, whereas the functional outcomes were variable. Remarkable heterogeneity was documented among the relevant studies with regard to several factors including the baseline characteristics of the cohorts, the non-response definition and previous treatment protocols. Larger prospective trials with appropriate control arms are therefore required to elucidate the potential benefit when switching between anti-VEGF agents in refractory nAMD.

MicroRNA-145 Regulates Pathological Retinal Angiogenesis by Suppression of TMOD3

Pathological angiogenesis is a hallmark of various vascular diseases, including vascular eye disorders. Dysregulation of microRNAs (miRNAs), a group of small regulatory RNAs, has been implicated in the regulation of ocular neovascularization. This study investigated the specific role of microRNA-145 (miR-145) in regulating vascular endothelial cell (EC) function and pathological ocular angiogenesis in a mouse model of oxygen-induced retinopathy (OIR). Expression of miR-145 was significantly upregulated in OIR mouse retinas compared with room air controls. Treatment with synthetic miR-145 inhibitors drastically decreased levels of pathological neovascularization in OIR, without substantially affecting normal developmental angiogenesis. In cultured human retinal ECs, treatment with miR-145 mimics significantly increased the EC angiogenic function, including proliferation, migration, and tubular formation, whereas miR-145 inhibitors attenuated in vitro angiogenesis. Tropomodulin3 (TMOD3), an actin-capping protein, is a direct miR-145 target and is downregulated in OIR retinas. Treatment with miR-145 mimic led to TMOD3 inhibition, altered actin cytoskeletal architecture, and elongation of ECs. Moreover, inhibition of TMOD3 promoted EC angiogenic function and pathological neovascularization in OIR and abolished the vascular effects of miR-145 inhibitors in vitro and in vivo. Overall, our findings indicate that miR-145 is a novel regulator of TMOD3-dependent cytoskeletal architecture and pathological angiogenesis and a potential target for development of treatments for neovascular eye disorders.

CRISPR-LbCpf1 prevents choroidal neovascularization in a mouse model of age-related macular degeneration

LbCpf1, derived from Lachnospiraceae bacterium ND2006, is a CRISPR RNA-guided endonuclease and holds promise for therapeutic applications. Here we show that LbCpf1 can be used for therapeutic gene editing in a mouse model of age-related macular degeneration (AMD). The intravitreal delivery of LbCpf1, targeted to two angiogenesis-associated genes encoding vascular endothelial growth factor A (Vegfa) and hypoxia inducing factor 1a (Hif1a), using adeno-associated virus, led to efficient gene disruption with no apparent off-target effects in the retina and retinal pigment epithelium (RPE) cells. Importantly, LbCpf1 targeted to Vegfa or Hif1a in RPE cells reduced the area of laser-induced choroidal neovascularization as efficiently as aflibercept, an anti-VEGF drug currently used in the clinic, without inducing cone dysfunction. Unlike aflibercept, LbCpf1 targeted to Vegfa or Hif1a achieved a long-term therapeutic effect on CNV, potentially avoiding repetitive injections. Taken together, these results indicate that LbCpf1-mediated in vivo genome editing to ablate pathologic angiogenesis provides an effective strategy for the treatment of AMD and other neovascularization-associated diseases.

Intraocular Penetration of a vNAR: In Vivo and In Vitro VEGF165 Neutralization

Variable new antigen receptor domain (vNAR) antibodies are novel, naturally occurring antibodies that can be isolated from naïve, immune or synthetic shark libraries. These molecules are very interesting to the biotechnology and pharmaceutical industries because of their unique characteristics related to size and tissue penetrability. There have been some approved anti-angiogenic therapies for ophthalmic conditions, not related to vNAR. This includes biologics and chimeric proteins that neutralize vascular endothelial growth factor (VEGF)₁₆₅, which are injected intravitreal, causing discomfort and increasing the possibility of infection. In this paper, we present a vNAR antibody against human recombinant VEGF₁₆₅ (rhVEGF₁₆₅) that was isolated from an immunized Heterodontus francisci shark. A vNAR called V13, neutralizes VEGF₁₆₅ cytokine starting at 75 μg/mL in an in vitro assay based on co-culture of normal human dermal fibroblasts (NHDFs) and green fluorescence protein (GFP)-labeled human umbilical vein endothelial cells (HUVECs) cells. In the oxygen-induced retinopathy model in C57BL/6:Hsd mice, we demonstrate an endothelial cell count decrease. Further, we demonstrate the intraocular penetration after topical administration of 0.1 μg/mL of vNAR V13 by its detection in aqueous humor in New Zealand rabbits with healthy eyes after 3 h of application. These findings demonstrate the potential of topical application of vNAR V13 as a possible new drug candidate for vascular eye diseases.

Ferrochelatase is a therapeutic target for ocular neovascularization

Ocular neovascularization underlies major blinding eye diseases such as “wet” age‐related macular degeneration (AMD). Despite the successes of treatments targeting the vascular endothelial growth factor (VEGF) pathway, resistant and refractory patient populations necessitate discovery of new therapeutic targets. Using a forward chemical genetic approach, we identified the heme synthesis enzyme ferrochelatase (FECH) as necessary for angiogenesis in vitro and in vivo. FECH is overexpressed in wet AMD eyes and murine choroidal neovascularization; siRNA knockdown of Fech or partial loss of enzymatic function in the Fech^m1Pas mouse model reduces choroidal neovascularization. FECH depletion modulates endothelial nitric oxide synthase function and VEGF receptor 2 levels. FECH is inhibited by the oral antifungal drug griseofulvin, and this compound ameliorates choroidal neovascularization in mice when delivered intravitreally or orally. Thus, FECH inhibition could be used therapeutically to block ocular neovascularization.

Microfluidic methods for aptamer selection and characterization

Nucleic acid aptamers have tremendous potential as molecular recognition elements in biomedical targeting, analytical arrays, and self-signaling sensors. However, practical limitations and inefficiencies in the process of selecting novel aptamers (SELEX) have hampered widespread adoption of aptamer technologies. Many factors have recently contributed to more effective aptamer screening, but no influence has done more to increase the efficiency, scale, and automation of aptamer selection than that of new microfluidic SELEX techniques. This review introduces aptamers as a powerful chemical and biological tool, briefly highlights traditional SELEX techniques and their limitations, covers in detail the recent advancements in microfluidic methods of aptamer selection and characterization, and suggests possible future directions of the field.

Therapeutic miRNA and siRNA: Moving from Bench to Clinic as Next Generation Medicine

In the past few years, therapeutic microRNA (miRNA) and small interfering RNA (siRNA) are some of the most important biopharmaceuticals that are in commercial space as future medicines. This review summarizes the patents of miRNA- and siRNA-based new drugs, and also provides a snapshot about significant biopharmaceutical companies that are investing for the therapeutic development of miRNA and siRNA molecules. An insightful view about individual siRNA and miRNA drugs has been depicted with their present status, which is gaining attention in the therapeutic landscape. The efforts of the biopharmaceuticals are discussed with the status of their preclinical and/or clinical trials. Here, some of the setbacks have been highlighted during the biopharmaceutical development of miRNA and siRNA as individual therapeutics. Finally, a snapshot is illustrated about pharmacokinetics, pharmacodynamics with absorption, distribution, metabolism, and excretion (ADME), which is the fundamental development process of these therapeutics, as well as the delivery system for miRNA- and siRNA-based drugs.

Predictive models of long-term anatomic outcome in age-related macular degeneration treated with as-needed Ranibizumab

Background

To analyze predictors and develop predictive models of anatomic outcome in neovascular age-related macular degeneration (AMD) treated with as-needed ranibizumab after 4 years of follow-up.

Methods

A multicenter consecutive case series non-interventional study was performed. Clinical, funduscopic and OCT characteristics of 194 treatment-naïve patients with AMD treated with as-needed ranibizumab for at least 2 years and up to 4 years were analyzed at baseline, 3 months and each year until the end of the follow-up. Baseline demographic and angiographic characteristics were also evaluated. R Statistical Software was used for statistical analysis. Main outcome measure was final anatomic status.

Results

Factors associated with less probability of preserved macula were diagnosis in 2009, older age, worse vision, presence of atrophy/fibrosis, pigment epithelium detachment, and geographic atrophy/fibrotic scar/neovascular AMD in the fellow eye. Factors associated with higher probability of GA were presence of atrophy and greater number of injections, whereas male sex, worse vision, lesser change in central macular thickness and presence of fibrosis were associated with less probability of GA as final macular status. Predictive model of preserved macula vs. GA/fibrotic scar showed sensibility of 77.78% and specificity of 69.09%. Predictive model of GA vs. fibrotic scar showed sensibility of 68.89% and specificity of 72.22%.

Conclusions

We identified predictors of final macular status, and developed two predictive models. Predictive models that we propose are based on easily harvested variables, and, if validated, could be a useful tool for individual patient management and clinical research studies.

Engineering of PEDF-Expressing Primary Pigment Epithelial Cells by the SB Transposon System Delivered by pFAR4 Plasmids

Neovascular age-related macular degeneration (nvAMD) is characterized by choroidal blood vessels growing into the subretinal space, leading to retinal pigment epithelial (RPE) cell degeneration and vision loss. Vessel growth results from an imbalance of pro-angiogenic (e.g., vascular endothelial growth factor [VEGF]) and anti-angiogenic factors (e.g., pigment epithelium-derived factor [PEDF]). Current treatment using intravitreal injections of anti-VEGF antibodies improves vision in about 30% of patients but may be accompanied by side effects and non-compliance. To avoid the difficulties posed by frequent intravitreal injections, we have proposed the transplantation of pigment epithelial cells modified to overexpress human PEDF. Stable transgene integration and expression is ensured by the hyperactive Sleeping Beauty transposon system delivered by pFAR4 miniplasmids, which have a backbone free of antibiotic resistance markers. We demonstrated efficient expression of the PEDF gene and an optimized PEDF cDNA sequence in as few as 5 × 10³ primary cells. At 3 weeks post-transfection, PEDF secretion was significantly elevated and long-term follow-up indicated a more stable secretion by cells transfected with the optimized PEDF transgene. Analysis of transgene insertion sites in human RPE cells showed an almost random genomic distribution. The results represent an important contribution toward a clinical trial aiming at a non-viral gene therapy of nvAMD.

Vascular Endothelial Growth Factor and Diabetic Retinal Disease

Diabetic retinal disease remains a leading cause of blindness among working-aged adults around the world. Until this decade, laser photocoagulation for both proliferative diabetic retinopathy and diabetic macular edema had been the standard of care for millions of patients. The introduction of vascular endothelial growth factor inhibitors (anti-VEGF) and subsequent clinical trials demonstrating their efficacy for treatment of diabetic eye disease have established a new standard in treatment of center-involved diabetic macular edema that is highly specific to the pathologic process and highly effective in preserving and improving vision. This review focuses on clinically relevant developments that led to the shift from focal/grid laser photocoagulation to anti-VEGF injections in the treatment of center-involved diabetic macular edema (DME), with an overview of the disease pathophysiology, clinical disease course, and available anti-VEGF agents. This article also reviews the scientific evidence exploring the use of anti-VEGF agents in nonproliferative and proliferative diabetic retinopathy.

Effects of commonly used intravitreal anti-vascular endothelial growth factor drugs on mesenchymal stem cells derived from the limbus and ciliary body

BACKGROUND

To investigate the effects of commonly used intravitreal anti-vascular endothelial growth factor (anti-VEGF) antibodies on proliferation index and viability of mesenchymal stem cells derived from ciliary body and limbus (CB-MSC and LMSC).

METHODS

CB-MSCs and LMSCs were isolated from newborn rats' eyes, and they were expanded in medium by the explant method. Intravitreally used anti-VEGF drugs, aflibercept, bevacizumab and ranibizumab were tested into the 16-well plates, respectively, at four different concentrations. After keeping them for 48 h, the proliferation indexes and viabilities of CB-MSCs and LMSCs were compared separately by Real-Time Cell Analyzer and Methylthiazoltetrazoli (MTT) test.

RESULTS

Anti-VEGFs used at 5-times and 10-times of the standard clinical dosage caused statistically significant negative effects on proliferation indexes of CB-MSCs and LMSCs at the 24^th hour compared to control group. Only the anti-VEGF group that had 10-times dosage of those used clinically had a statistically significant negative effect on the viabilties of CB-MSCs and LMSCs.

CONCLUSION

Administrations of high doses or repeated standard doses of intravitreal anti-VEGF agents may affect the proliferation indexes and viabilities of CB-MSCs and LMSCs adversely. These novel findings deserve further in vivo investigations.

Status and Prospects of Aptamers as Drug Components

The unique properties of nucleic acid aptamers and their suitability to therapeutic applications have attracted the attention of researchers for more than 2 decades. Aptamers exhibit significant advantages relative to antibody-based therapeutics and can serve dual roles as either the therapeutic agent itself or a targeting modality. Despite this intense research interest, aptamers have been slow to reach the clinic, partly due to practical limitations that can be overcome by rational chemical modifications and ingenious aptamer selection approaches. This review highlights the latest efforts to use aptamers in therapeutic applications, the key properties of aptamers that can be exploited, the aptamers that are currently in clinical trials, as well as speculation on the future of aptamers in the field of nanomedicine.

Tight junction modulation of the blood brain barrier: CNS delivery of small molecules

The blood brain barrier (BBB) represents a major obstacle for targeted drug delivery to the brain for the treatment of central nervous system (CNS) disorders. Significant advances in barrier research over the past decade has led to the discovery of an increasing number of structural and regulatory proteins in tight junctions (TJ) and adherens junctions (AJ). These discoveries are providing the framework for the development of novel TJ modulators which can act specifically and temporarily to alter BBB function and regulate paracellular uptake of molecules. TJ modulators that have shown therapeutic potential in preclinical models include claudin-5 and occludin siRNAs, peptides derived from zonula occludens toxin as well as synthetic peptides targeting the extracellular loops of TJs. Adding to the array of modulating agents are novel mechanisms of BBB regulation such as focused ultrasound (FUS). This review will give a succinct overview of BBB biology and TJ modulation in general. Novel insights into BBB regulation in health and disease will also be summarized.

Molecular features of interaction between VEGFA and anti-angiogenic drugs used in retinal diseases: a computational approach

Anti-angiogenic agents are biological drugs used for treatment of retinal neovascular degenerative diseases. In this study, we aimed at in silico analysis of interaction of vascular endothelial growth factor A (VEGFA), the main mediator of angiogenesis, with binding domains of anti-angiogenic agents used for treatment of retinal diseases, such as ranibizumab, bevacizumab and aflibercept. The analysis of anti-VEGF/VEGFA complexes was carried out by means of protein-protein docking and molecular dynamics (MD) coupled to molecular mechanics-Poisson Boltzmann Surface Area (MM-PBSA) calculation. Molecular dynamics simulation was further analyzed by protein contact networks. Rough energetic evaluation with protein-protein docking scores revealed that aflibercept/VEGFA complex was characterized by electrostatic stabilization, whereas ranibizumab and bevacizumab complexes were stabilized by Van der Waals (VdW) energy term; these results were confirmed by MM-PBSA. Comparison of MM-PBSA predicted energy terms with experimental binding parameters reported in literature indicated that the high association rate (Kon) of aflibercept to VEGFA was consistent with high stabilizing electrostatic energy. On the other hand, the relatively low experimental dissociation rate (Koff) of ranibizumab may be attributed to lower conformational fluctuations of the ranibizumab/VEGFA complex, higher number of contacts and hydrogen bonds in comparison to bevacizumab and aflibercept. Thus, the anti-angiogenic agents have been found to be considerably different both in terms of molecular interactions and stabilizing energy. Characterization of such features can improve the design of novel biological drugs potentially useful in clinical practice.

Current choice of treatments for neovascular AMD

Age-related macular degeneration is the leading cause of irreversible blindness in developed countries with the neovascular form accounting for the majority of severe vision loss in the disease. The management of wet age-related macular degeneration has improved drastically in the past decade as anti-VEGF agents took its place at the forefront of treatment. As the choice of therapy is based on a number of factors, this review summarizes the pivotal studies that brought these agents to use and compares the different agents currently available. This review also briefly describes the promising new therapies that are in development.

Advances in pharmacotherapy for wet age-related macular degeneration

INTRODUCTION

In developed countries, neovascular age-related macular degeneration (AMD) is the leading cause of irreversible central blindness. Although AMD pathogenesis is complex and still not fully understood, many involved mechanisms are already partially known and could be promising targets for future therapies. Currently, anti-VEGF drugs are the standard care of this condition.

AREAS COVERED

This review summarizes both the current available and the emerging pharmacological therapies for the management of neovascular AMD. At first, we briefly focused on anti-VEGF compounds that are commonly used. Then, we reviewed the mechanisms of action and potential advantages of new candidate drugs that are being evaluated in clinical trials.

EXPERT OPINION

Although anti-VEGF drugs have shown mild-term good efficacy and safety profile in the treatment of neovascular AMD, they are far away from being a perfect therapy. Pharmacological research should focus on finding new molecular targets in the AMD pathogenetical pathway and on developing longer lasting agents or new drug delivery systems. Besides the development of new drugs, a better characterization of patients is also needed, taking into account variables such as choroidal neovascularization subtypes and genetic factors, in order to identify a tailored treatment for each patient.

Management of neovascular age-related macular degeneration: current state-of-the-art care for optimizing visual outcomes and therapies in development

Contemporary management of neovascular age-related macular degeneration (AMD) has evolved significantly over the last few years. The goal of treatment is shifting from merely salvaging vision to maintaining a high quality of life. There have been significant breakthroughs in the identification of viable drug targets and gene therapies. Imaging tools with near-histological precision have enhanced our knowledge about pathophysiological mechanisms that play a role in vision loss due to AMD. Visual, social, and vocational rehabilitation are all important treatment goals. In this review, evidence from landmark clinical trials is summarized to elucidate the optimum modern-day management of neovascular AMD. Therapeutic strategies currently under development, such as gene therapy and personalized medicine, are also described.

The genetics of age-related macular degeneration (AMD)--Novel targets for designing treatment options?

Age-related macular degeneration (AMD) is a progressive disease of the central retina and the main cause of legal blindness in industrialized countries. Risk to develop the disease is conferred by both individual as well as genetic factors with the latter being increasingly deciphered over the last decade. Therapeutically, striking advances have been made for the treatment of the neovascular form of late stage AMD while for the late stage atrophic form of the disease, which accounts for almost half of the visually impaired, there is currently no effective therapy on the market. This review highlights our current knowledge on the genetic architecture of early and late stage AMD and explores its potential for the discovery of novel, target-guided treatment options. We reflect on current clinical and experimental therapies for all forms of AMD and specifically note a persisting lack of efficacy for treatment in atrophic AMD. We further explore the current insight in AMD-associated genes and pathways and critically question whether this knowledge is suited to design novel treatment options. Specifically, we point out that known genetic factors associated with AMD govern the risk to develop disease and thus may not play a role in its severity or progression. Treatments based on such knowledge appear appropriate rather for prevention than treatment of manifest disease. As a consequence, future research in AMD needs to be greatly focused on approaches relevant to the patients and their medical needs.

Funduscopic results after 4-year follow-up treatment with ranibizumab for age-related macular degeneration in a region of Spain

Background

The study aims to survey longstanding funduscopic and functional outcomes of age-related macular degeneration (AMD) after ranibizumab treatment and verify the accuracy of a new method to compare the retinal thickness measured with different optical coherence tomography (OCT) tools.

Methods

Case series included 314 eyes with 2–4 years of follow-up. Main Outcome Measures were visual acuity (VA), number of injections, retinal thickness, OCT morphology, and final macular funduscopic status.

Results

One hundred twenty-two men and 177 women (mean age, 78.3 years) were included. The mean time to the first injection was 17.3 ± 14.6 days. Initial VA was O.8(20/125) ± 0.5; 0.7(20/100) ± 0.5 at 3 months; 0.8(20/125) ± 0.5 at a year; 1(20/200) ± 0.6 at year 2; 1(20/200) ± 0.6 at year 3 and 1.1(20/250) ± 0.6 at year 4. Number of visits at 3 months was 2.7 ± 0.8; 7.3 ± 2.1 at a year; 5.2 ± 2.7 along the 2nd year; 3.9 ± 2.3 at year 3 and 3.6 ± 2.2 at year 4. Number of injections at 3 months was 2.6 ± 0.5; 3.9 ± 1.5 at a year; 1.1 ± 1.5 along the 2nd year; 1.5 ± 2.4 at year 3 and 1.8 ± 3.1 at year 4. Patients with worse VA outcomes received more injections and were older. The formula to calculate changes in retinal thickness showed a 30% reduction in thickness, which correlated well with the OCT morphology. Patients with polypoidal choroidal vasculopathy (PCV) had a worse final outcome. The final disciform macular status (37%) was related to fewer injections and a greater decrease in thickness. Final well-preserved maculas (12.%) needed more injections and treatment changes; those that were atrophic at the final visit (30.8%) had a worse initial VA and greater decrease in thickness at the 3-month visit.

Conclusions

Younger patients had better final outcomes. Our method to compare retinal thickness using different OCT tools worked well. The final visual outcome after a long follow-up was poor, which may be related to advanced age, poor initial VA, and the high incidence of final fibrosis or atrophy.

Emodin-loaded magnesium silicate hollow nanocarriers for anti-angiogenesis treatment through inhibiting VEGF

The applications of anti-VEGF (vascular endothelial growth factor) treatment in ophthalmic fields to inhibit angiogenesis have been widely documented in recent years. However, the hydrophobic nature of many agents makes its delivery difficult in practice. Therefore, the aim of the present study was to introduce a new kind of hydrophobic drug carrier by employing nanoparticles with a hollow structure inside. Followed by the synthesis and characterization of magnesium silicate hollow spheres, cytotoxicity was evaluated in retina capillary endothelial cells. The loading and releasing capacity were tested by employing emodin, and the effect on VEGF expression was performed at the gene and protein level. Finally, an investigation on angiogenesis was carried on fertilized chicken eggs. The results indicated that the magnesium silicate nanoparticles had low toxicity. Emodin–MgSiO₃ can inhibit the expression of both VEGF gene and protein effectively. Angiogenesis of eggs was also reduced significantly. Based on the above results, we concluded that magnesium silicate hollow spheres were good candidates as drug carriers with enough safety.