Anti-vascular endothelial growth factor therapy for neovascular ocular diseases other than age-related macular degeneration

Systemic lupus erythematosus (SLE) associated uveitis in India - A case series

PURPOSE

To report the uveitic manifestations of patients with systemic lupus erythematosus (SLE).

METHODS

This was a retrospective analysis of all SLE cases with ocular manifestations seen by a single ophthalmologist between 2015 and December 2021.

RESULTS

In total, seven patients with a median age of 40 (range 18-50) years were included in the study. Female (85.7%) predominance was noted. Ocular findings were bilateral in 71% (five patients) of cases. Majority (10 eyes, 83%) of the patients had retinal vasculitis as the common finding. Antinuclear antibodies were positive in all the patients. The vision improved in two (16.6%) eyes, was stable in eight (66%) eyes, and worsened in one (8%) eye. All the patients were treated with oral steroids along with immunosuppressive agents.

CONCLUSION

Though SLE is rare cause of uveitis, it can be associated with significant ocular morbidity. Hence, early diagnosis and treatment can salvage vision in many cases.

Retinal and Choroidal Neovascularization Antivascular Endothelial Growth Factor Treatments: The Role of Gene Therapy

Neovascularization in ocular vessels causes a major disease burden. The most common causes of choroidal neovascularization (CNV) are age-related macular degeneration and diabetic retinopathy, which are the leading causes of irreversible vision loss in the adult population. Vascular endothelial growth factor (VEGF) is critical for the formation of new vessels and is the main regulator in ocular angiogenesis and vascular permeability through its receptors. Laser therapy and antiangiogenic factors have been used for CNV treatment. Bevacizumab, ranibizumab, and aflibercept are commonly used anti-VEGF agents; however, high costs and the need for frequent intraocular injections are major drawbacks of anti-VEGF drugs. Gene therapy, given the potency of one-time treatment and no need for frequent injections offers the real possibility of such a lasting treatment, with fewer adverse effects and higher patient quality of life. Herein, we reviewed the role of gene therapy in the CNV treatment. In addition, we discuss the advantages and challenges of current treatments compared with gene therapy.

Recent advances in ocular drug delivery systems and targeting VEGF receptors for management of ocular angiogenesis: A comprehensive review

Background

Angiogenic ocular diseases address the main source of vision impairment or irreversible vision loss. The angiogenesis process depends on the balance between the pro-angiogenic and anti-angiogenic factors. An imbalance between these factors leads to pathological conditions in the body. The vascular endothelial growth factor is the main cause of pathological conditions in the ocular region. Intravitreal injections of anti-angiogenic drugs are selective, safe, specific and revolutionized treatment for ocular angiogenesis. But intravitreal injections are invasive techniques with other severe complications. The area of targeting vascular endothelial growth factor receptors progresses with novel approaches and therapeutically based hope for best clinical outcomes for patients through the developments in anti-angiogenic therapy.

Main text

The present review article gathers prior knowledge about the vascular endothelial growth factor and associated receptors with other angiogenic and anti-angiogenic factors involved in ocular angiogenesis. A focus on the brief mechanism of vascular endothelial growth factor inhibitors in the treatment of ocular angiogenesis is elaborated. The review also covers various recent novel approaches available for ocular drug delivery by comprising a substantial amount of research works. Besides this, we have also discussed in detail the adoption of nanotechnology-based drug delivery systems in ocular angiogenesis by comprising literature having recent advancements. The clinical applications of nanotechnology in terms of ocular drug delivery, risk analysis and future perspectives relating to the treatment approaches for ocular angiogenesis have also been presented.

Conclusion

The novel ocular drug delivery systems involving nanotechnologies are of great importance in the ophthalmological sector to overcome traditional treatments with many drawbacks. This article gives a detailed insight into the various approaches that are currently available to be a road map for future research in the field of ocular angiogenesis disease management.

ABCC6, Pyrophosphate and Ectopic Calcification: Therapeutic Solutions

Pathological (ectopic) mineralization of soft tissues occurs during aging, in several common conditions such as diabetes, hypercholesterolemia, and renal failure and in certain genetic disorders. Pseudoxanthoma elasticum (PXE), a multi-organ disease affecting dermal, ocular, and cardiovascular tissues, is a model for ectopic mineralization disorders. ABCC6 dysfunction is the primary cause of PXE, but also some cases of generalized arterial calcification of infancy (GACI). ABCC6 deficiency in mice underlies an inducible dystrophic cardiac calcification phenotype (DCC). These calcification diseases are part of a spectrum of mineralization disorders that also includes Calcification of Joints and Arteries (CALJA). Since the identification of ABCC6 as the “PXE gene” and the development of several animal models (mice, rat, and zebrafish), there has been significant progress in our understanding of the molecular genetics, the clinical phenotypes, and pathogenesis of these diseases, which share similarities with more common conditions with abnormal calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into inorganic pyrophosphate (PPi) and adenosine by the ectonucleotidases NPP1 and CD73 (NT5E). PPi is a potent endogenous inhibitor of calcification, whereas adenosine indirectly contributes to calcification inhibition by suppressing the synthesis of tissue non-specific alkaline phosphatase (TNAP). At present, therapies only exist to alleviate symptoms for both PXE and GACI; however, extensive studies have resulted in several novel approaches to treating PXE and GACI. This review seeks to summarize the role of ABCC6 in ectopic calcification in PXE and other calcification disorders, and discuss therapeutic strategies targeting various proteins in the pathway (ABCC6, NPP1, and TNAP) and direct inhibition of calcification via supplementation by various compounds.

Cyclic RGD Peptide Targeting Coated Nano Drug Co-Delivery System for Therapeutic Use in Age-Related Macular Degeneration Disease

Vascular endothelial growth factor (VEGF) expression increased significantly in the pathogenesis of age-related macular degeneration, which induced the formation of pathological blood vessels. Dexamethasone is an exogenous anti-angiogenic drug while bevacizumab is an endogenous anti-angiogenic drug. They both have been widely used in ophthalmology. However, independent administration is not enough to completely block the development of choroidal neovascularization (CNV), and the number of eyes vitreous injections is limited. Reasonable combination of drugs may produce significantly better therapeutic effect than single drug treatment. The cyclic RGD (cRGD) peptide has a particularly high affinity with retinal pigment epithelial cells, where VEGF secretes from. In this study, we prepared nanoparticles of bevacizumab and dexamethasone with cRGD peptide as the target (aBev/cRGD-DPPNs). The particle size of the aBev/cRGD-DPPNs was 213.8 ± 1.5 nm, SEM results showed that the nano-carriers were well dispersed and spherical. The cell uptake study demonstrated the selectivity of the aBev/cRGD-DPPN to ARPE-19 with α_Vβ₃ over expressed. The aBev/cRGD-DPPNs had a better apoptosis induction effect and an obvious inhibitory effect on migration, invasion, and capillary-like structures formation of human umbilical vein epithelial cells. The fluorescein fundus angiography study, immunohistochemistry and histopathological evaluation showed the aBev/cRGD-DPPNs greatly reduced the development of CNV on a rabbit model.

The Top 100 Most-Cited Papers on Intravitreal Injections: A Bibliographic Perspective

Purpose

To analyze the top 100 most-cited papers on pars intravitreal injections.

Methods

Literature search using the bibliographic databases of the ISI Web of Knowledge for all types of publications on intravitreal injections published between 1965 and 2019 in peer-reviewed journals.

Results

Eighty-three of the top 100 papers on intravitreal injections were published in ophthalmology journals, their majority in the top five Q1 leading journals in the field. They originated from 16 different countries, predominantly from the USA (n=52), and were all published in English. These manuscripts cover a wide spectrum of topics but were mostly focused on retinal diseases (n=60) and the use of anti-VEGF or steroid agents (n=75).

Discussion

This bibliographic study provides a unique perspective on the evolution and assimilation of intravitreal injections, from their introduction, through their present role as the most common therapeutic procedure in ophthalmology, to future developments.

Triptolide-nanoliposome-APRPG, a novel sustained-release drug delivery system targeting vascular endothelial cells, enhances the inhibitory effects of triptolide on laser-induced choroidal neovascularization

PURPOSE

To investigate whether triptolide-nanoliposome-APRPG (TP-nanolip-APRPG), a novel sustained-release nano-drug delivery system that targets vascular endothelial cells, could enhance the inhibition of triptolide (TP) on laser-induced choroidal neovascularization (CNV).

METHODS

TP was encapsulated with or without APRPG (Ala-Pro-Arg-Pro-Gly) peptide-modified nanoliposomes. CNV was induced by laser photocoagulation in C57BL/6J mice. One microliter of 10 μg free TP monomer, TP-nanolip containing 10 μg TP, TP-nanolip-APRPG containing 10 μg TP, or an identical volume of PBS was intravitreally injected in mice immediately after laser photocoagulation. Seven days after laser photocoagulation, CNV volumes were calculated in each group. Infiltration of M2 macrophages as well as protein levels of vascular endothelial growth factor (VEGF) and inflammatory factors including ICAM-1 and MCP-1 in the RPE-choroid complex were determined. In vitro assays for cell proliferation, migration, and tube formation were also performed.

RESULTS

TP-nanolip-APRPG was successfully synthesized and exhibited good TP delivery and enhanced the cellular uptake of TP in vitro. In vitro studies showed that TP-nanolip-APRPG was a better inhibitor of cell proliferation (31.34 ± 3.89 % vs 41.25 ± 4.67 % vs 53.55 ± 5.76 %), migration (62.60 ± 8.88 vs 104.60 ± 13.32 vs 147.00 ± 13.15), and tube formation (681.26 ± 108.15 vs 926.75 ± 54.01 vs 1189.84 ± 157.14) than TP-nanolip or free TP (all P < 0.05). Intravitreal injections of free TP (77588.10±7719.28 μm³), TP-nanolip (64628.23 ± 5857.96 μm³), and TP-nanolip-APRPG (50880.34 ± 6606.56 μm³) inhibited the development of CNV compared with the PBS control group (120338.07 ± 17428.90 μm³) (P < 0.01, n=6). TP-nanolip-APRPG and TP-nanolip significantly down-regulated the protein levels of VEGF (152.76±19.55 vs 182.24±19.98 vs 208.55±21.93 pg/mg total protein) and inflammatory factors including ICAM-1 (61.69±3.49 vs 72.04±3.49 vs 81.92±4.09 ng/mg total protein) and MCP-1 (40.14±3.50 vs 50.75±4.18 vs 60.27±5.23 pg/mg total protein) compared with the free TP monomer group (all P < 0.05, n=8), which paralleled the decreased infiltration of M2 macrophages in the CNV lesions. Moreover, no influence on retinal morphology and function was observed before or after treatment in each group (P > 0.05, n=6).

CONCLUSIONS

TP-nanolip-APRPG, a novel sustained-release drug delivery system targeting endothelial cells of CNV lesions, could enhance TP inhibition of the development of CNV without toxicity in the retina, suggesting therapeutic potential for CNV-related diseases in future clinical practice.

Intravitreal hydrogels for sustained release of therapeutic proteins

This review highlights how hydrogel formulations can improve intravitreal protein delivery to the posterior segment of the eye in order to increase therapeutic outcome and patient compliance. Several therapeutic proteins have shown excellent clinical successes for the treatment of various intraocular diseases. However, drug delivery to the posterior segment of the eye faces significant challenges due to multiple physiological barriers preventing drugs from reaching the retina, among which intravitreal protein instability and rapid clearance from the site of injection. Hence, frequent injections are required to maintain therapeutic levels. Moreover, because the world population ages, the number of patients suffering from ocular diseases, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR) is increasing and causing increased health care costs. Therefore, there is a growing need for suitable delivery systems able to tackle the current limitations in retinal protein delivery, which also may reduce costs. Hydrogels have shown to be promising delivery systems capable of sustaining release of therapeutic proteins and thus extending their local presence. Here, an extensive overview of preclinically developed intravitreal hydrogels is provided with attention to the rational design of clinically useful intravitreal systems. The currently used polymers, crosslinking mechanisms, in vitro/in vivo models and advancements are discussed together with the limitations and future perspective of these biomaterials.

Triptolide attenuates laser-induced choroidal neovascularization via M2 macrophage in a mouse model

PURPOSE

To investigate whether triptolide has inhibitory effects on the development of choroidal neovascularization (CNV), together with its underlying anti-angiogenic mechanisms.

METHODS

CNV was induced in C57BL/6 J mice using laser photocoagulation. Triptolide at concentrations of 0.035 and 0.07 mg/kg body weight (BW) or the same volume of phosphate-buffered saline (PBS) was intraperitoneally injected into mice 2 days before laser photocoagulation, which was continued daily till the end of the experiment. CNV areas were measured on day 7. The numbers of M1, M2, and F4/80⁺ macrophages were detected on day 1, 3, and 7 in each group. The levels of vascular endothelial growth factor (VEGF) and inflammatory molecules,including intercellular adhesion molecule (ICAM)-1,tumor necrosis factor (TNF)-α, and interleukin 6 (IL-6) were determined by enzyme-linked immunosorbent assay. Cell proliferation, migration, and tube-formation assays were performed in vitro.

RESULTS

Triptolide at doses of 0.035 mg/kg BW (66,562 ± 39,253 μm², n = 5, P＜0.05) and 0.07 mg/kg BW (37,271 ± 25,182 μm², n = 5, P＜0.001) significantly reduced CNV areas by 54.9 and 74.8 %, respectively, compared with PBS control (147,699 ± 112,900 μm², n = 5) in a dose-dependent manner. Protein levels of VEGF, ICAM-1, TNF-α, and IL-6 in the RPE-choroid-sclera complex were significantly downregulated by triptolide treatment on day 3, which was in accordance with the reduced number of infiltrated F4/80⁺ macrophages and the reduced ratio of M2/F4/80⁺ macrophages. However, no toxic effects of triptolide on the retina or other systemic organs were observed. In addition, triptolide treatment exerted inhibitory effects on cell proliferation, migration, and tube formation in vitro in a concentration-dependent manner.

CONCLUSIONS

Triptolide has therapeutic potential in CNV owing to its anti-angiogenic effect.

Updates on Gene Therapy for Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR), a leading cause of visual impairment in the developed country, is characterized by vascular lesions and neuronal damage of the retina. Treatment options for this condition are currently limited. The advent of therapy targeting vascular endothelial growth factor (VEGF) demonstrated significant benefits to patients with DR. However, this treatment is limited by its short half-life and requirement for frequent invasive intravitreal injections. In addition, many patients failed to achieve clinically significant improvement in visual function. Gene therapy has the potential to provide an alternative treatment for DR with distinct advantages, such as longer therapeutic effect, less injection frequency, ability to intervene at disease onset, and potentially fewer side effects.

RECENT FINDINGS

Strategies for gene therapy in DR, stemming from the current understanding of the disease pathogenesis, focus on the inhibition of neovascularization and protection of neurovascular degeneration in the retina. Studies with promising results have mainly focussed on animal models due to efficacy and safety concerns, despite a number of successful preclinical studies using adeno-associated virus-mediated transduction to treat both vascular dysfunction and neuronal degeneration. With the optimization of delivery vectors, transgene regulation, and outcome measure, gene therapy will potentially become available for patients with DR. This review provides an update on the current strategies utilized in DR gene therapy research. Several barriers to the clinical application of gene therapy for DR are highlighted, and future directions for this research are proposed.

Severe vaso-occlusive lupus retinopathy in the early stage of a pediatric patient with systemic lupus erythematosus: a case report

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multisystem, chronic, autoimmune disease which can affect any organ system including the eye. About one-third of the patients can be diagnosed with SLE-related eye involvement which is usually indicative of disease activity. Retinopathy is one of the most vision-threatening complications that can be associated with the disease.

PATIENT CONCERNS

An 11-year-old girl was hospitalized with complains of repeated swelling and pain in her extremities for 1 month, chest pain for 24 days, rash for 5 days and proteinuria for 1 day. On the morning of her fourth day in hospital, she suddenly complained of sudden, painless vision loss in the left eye. The ophthalmologist found that she had obstruction of central retinal vein and artery with diffuse retinal hemorrhages and macular edema.

DIAGNOSIS

The patient was diagnosed with systemic lupus erythematosus, lupus nephritis, and lupus retinopathy through her clinical manifestations and laboratory tests.

INTERVENTIONS

After diagnosis, she received steroid therapy, retinal laser photocoagulation, and intravitreal injection of dexamethasone (OZURDEX, Allergan Pharmaceuticals, Dublin, Ireland) early in her course.

OUTCOMES

At the latest follow-up, her vision improved partially. However, she still has the possibility of subsequent neovascular glaucoma and bleeding in the future.

CONCLUSIONS

An early diagnosis and the prompt therapeutic measures are necessary to prevent sight-threatening consequences, especially in pediatric patients with SLE.

The efficacy of systemic and intravitreal infliximab treatments in an endotoxin-induced uveitis model

Purpose: To compare the efficacy of systemic and intravitreal infliximab treatments in an experimental endotoxin-induced uveitis (EIU) model. Methods: Twenty-eight white New Zealand rabbits were equally divided into 4 groups. Group 1 received an intravitreal injection of 0.1 cc saline, group 2 received an intravitreal injection of 2 µg/0.1 cc lipopolysaccharide (LPS), group 3 received an intravitreal injection of 2 µg/0.1 cc LPS and 2 mg/0.1 cc infliximab, and group 4 received intravitreal injection of 2 µg/0.1 cc LPS and intravenous injection of 5 mg/kg infliximab. Clinical, biochemical (aqueous and vitreous humour protein levels and TNF-α concentrations), and histopathological evaluations were performed. Results: The clinical examination score was lower in group 4 than in group 2 (p = 0.006); but there was no significant difference between groups 2 and 3 (Bonferroni correction, p = 0.016). No statistically significant difference was found among groups 2, 3, and 4 for aqueous humour protein levels (p > 0.05). Significantly higher aqueous humour concentrations of TNF-α was measured in group 3 comparing to both group 1 and 4 (p = 0.003 and p = 0.002, respectively). No significant difference was found in vitreous protein levels or TNF-α concentrations among all study groups (Bonferroni correction, p = 0.026 and p = 0.101, respectively). Histopathological evaluation of the uveal tissue and anterior chamber reaction revealed the highest inflammation in group 3 (p < 0.001). In group 4, histopathological evaluation of uveal tissue was lower than in groups 2 and 3 (p < 0.001 and p = 0.001, respectively); whereas there was no difference in anterior chamber inflammation between groups 2 and 4 (p = 1.00). Conclusion: Intravitreal 2 mg/0.1 cc infliximab injection exacerbated inflammation in an EIU model; whereas systemic infliximab treatment at a dose of 5 mg/kg suppressed inflammation effectively and rapidly.

Optic Nerve Head Perfusion Before and After Intravitreal Antivascular Growth Factor Injections Using Optical Coherence Tomography-based Microangiography

PURPOSE

To use optical coherence tomography angiography (OCTA) to evaluate the changes in optic nerve head perfusion following intravitreal antivascular endothelial growth factor injections.

METHODS

Preinjection and postinjection intraocular pressure (IOP) and OCTA images were taken of both the injected and uninjected fellow eyes.

RESULTS

Mean preinjection IOP was 16.6±4.7 mm Hg, which increased to a mean of 40.3±13.0 mm Hg (P<0.0001) during the first postinjection image and remained elevated at 36.1±11.5 mm Hg (P<0.0001) during the second postinjection image. Although no significant change was observed in flux, vessel area density, or normalized flux when comparing the OCTA preinjection and first postinjection images, a significant decrease at the second postinjection image was observed (P=0.03, 0.02, and 0.03, respectively). No significant change was observed in the uninjected fellow eye during the same time period (P=0.47, 0.37, and 0.38, respectively).

CONCLUSIONS

Following an antivascular endothelial growth factor injection, mean IOP increased significantly and OCTA imaging of the optic nerve demonstrated a mild but significant decrease in optic nerve head perfusion parameters. Clinicians performing these injections should be aware of these findings and monitor the status of the optic nerve in patients undergoing injections.

Novel Long-acting Pharmacotherapy for Exudative Age Related Macular Degeneration

Exudative age-related macular degeneration (AMD) is a major indication for the administration of intravitreal injections of anti-VEGF agents, which have been established as a very effective pharmacotherapy for this disease. However, treatment with anti-VEGF agents requires several patient visits for monitoring and treatment. Strategies for achieving a longer duration of pharmacological action are currently being developed. These include the development of longer-acting drugs, and of novel technologies to increase the duration of action of administered agents. This manuscript will review the novel drugs and technologies currently being developed for achieving a longer-action pharmacotherapy for exudative AMD.

Clinical observations on the use of new anti-VEGF drug, conbercept, in age-related macular degeneration therapy: a meta-analysis

PURPOSE

Conbercept is a new anti-vascular endothelial growth factor (VEGF) drug approved for the treatment of age-related macular degeneration (AMD). Although this novel drug has been widely used in clinic, unlike other anti-VEGF drugs, validation and consensus on its method of clinical application and clinical safety have not yet been achieved.

METHODS

Relevant literature was searched on PubMed, Web of Science, China National Knowledge Internet, and Wanfang Data. Stata 12.0 was used for data analysis. Random- and fixed-effect models were employed to evaluate heterogeneity. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were utilized to measure the improvement of AMD patients.

RESULTS

In this study, we analyzed conbercept administration and compared its application with other control clinical methods for AMD treatment. Ranibizumab, triamcinolone, and traditional transpupillary thermotherapy (TTT) were administered in the control group. No differences were found in the BCVA and CRT improvement between the groups treated with conbercept and ranibizumab. However, the conbercept group had a lower serum VEGF level. After 3 months of treatment, conbercept led to a more significant BCVA and CRT improvement than triamcinolone. A more considerable BCVA improvement was observed in the group treated with conbercept than in the group treated with TTT. Moreover, even 6 months after the treatment, the effect of conbercept on CRT improvement was still more pronounced than that of TTT.

CONCLUSION

In AMD patients, conbercept exerts considerably more positive effects on the long-term BCVA and CRT improvement than triamcinolone and TTT. The serum VEGF level in the conbercept group was lower than that in the ranibizumab group.

Quantitative physiological measurements to evaluate the response of antivascular endothelial growth factor treatment in patients with neovascular diseases

Antivascular endothelial growth factor (VEGF) treatment is still used intravitreally worldwide for various neovascular diseases, despite other available, approved treatments. We performed a systematic search of the literature focused on visual physiology studies. We used the online biomedical search engine PubMed and searched key words including “M-chart,” “Preferential Hyperacuity Perimetry,” “microperimetry,” (MP) “electroretinography,” and “contrast sensitivity” to estimate treatment efficacy of anti-VEGF treatments in a quantitative manner. Many studies were identified which used a variety of methodologies, disease entities, injected agents, and patient populations, making it difficult to obtain a direct comparison of their results. However, favorable functional outcomes achieved using current quantitative methods would lend further confidence to the effectiveness of a treat-and-extend protocol using intravitreal anti-VEGF for the management of patients with neovascular diseases. Despite anti-VEGF's wide use, a well-designed longitudinal multicenter study to systematically evaluate and compare different physiological methods or parameters in patients with neovascular diseases is still lacking, though it would benefit therapeutic decisions.

Current Perspectives on the Use of Anti-VEGF Drugs as Adjuvant Therapy in Glaucoma

The approval of one of the first anti-vascular endothelial growth factor (VEGF) agents for the treatment of neovascular age-related macular degeneration one decade ago marked the beginning of a new era in the management of several sight-threatening retinal diseases. Since then, emerging evidence has demonstrated the utility of these therapies for the treatment of other ocular conditions characterized by elevated VEGF levels. In this article we review current perspectives on the use of anti-VEGF drugs as adjuvant therapy in the management of neovascular glaucoma (NVG). The use of anti-VEGFs for modifying wound healing in glaucoma filtration surgery (GFS) is also reviewed. Selected studies investigating the use of anti-VEGF agents or antimetabolites in GFS or the management of NVG have demonstrated that these agents can improve surgical outcomes. However, anti-VEGF agents have yet to demonstrate specific advantages over the more established agents commonly used today. Further studies are needed to evaluate the duration of action, dosing intervals, and toxicity profile of these treatments.

Daily Optical Coherence Tomography Examinations after First Antivascular Endothelial Growth Factor Injections: An Interventional Case Series

Purpose. To evaluate daily spectral-domain optical coherence tomography (SD-OCT) changes in naive-treatment patients with diagnosis of exudative age-related macular degeneration (AMD) treated with intravitreous bevacizumab (1.25 mg), during a 30-day follow-up period. Methods. In prospective, interventional study, SD-OCT was performed daily for 30 days after the first intravitreal injection. The baseline, initial-decrease, minimal, and final central retinal thicknesses (CRTs) were assessed. Results. Nine eyes of nine patients with neovascular AMD were enrolled. The mean baseline CRT was 625.3 ± 182.5 μm, and the mean final CRT was 383.4 ± 163.0 μm (mean difference, 206.1 ± 167.6 μm), a difference that reached significance (P = 0.006). After the first injection, the initial decrease in the CRT was seen as an average of one day after injection (mean CRT, 503.6 ± 189.10 μm; P = 0.0431). The speed of the reduction in the CRT tended to decrease by day 17. The mean CRT was 336.5 ± 105.44 μm and the mean minimal CRT on day 30 was 320.75 ± 96.38 μm. Conclusion. The CRT decreased early after the first injection. We observed a tendency for reductions in the speed with which the CRT decreased by day 17 after the first injection, which may affect retreatment regime.

A cluster of presumed, noninfectious endophthalmitis after intravitreal injection of bevacizumab: long-term follow-up

PURPOSE

To report the outcome of 5 consecutive cases of presumed, noninfectious endopththalmitis following intravitreal injection of bevacizumab (IVB).

METHODS

Ten pre-loaded syringes of bevacizumab (1.25 mg/50 µL) furnished by a compounding pharmacy were injected intravitreally. Treatments were performed in the operating room by the same surgeon on 2 consecutive days.

RESULTS

Of 10 eyes, 5 showed moderate to severe ocular inflammation within a few days of injection. All patients were treated in the same surgical session. Vitreous tap performed in the patient presenting with the most severe grade of inflammation was negative for bacteria and fungi. At the time of the vitreous biopsy, this patient was injected with vancomycin 1 mg/100 µL in the vitreous cavity. Other eyes with moderate inflammation received topical and systemic antibiotics and topical steroid treatment. Visual acuity returned to pre-endophthalmitis or better levels in all eyes within 1 month. The other 5 patients treated with IVB from the same batch in the other surgical session did not develop inflammation.

CONCLUSIONS

IVB can induce noninfectious endophthalmitis. The use of compounded syringes can explain clustering of the inflammation. We were unable to identify the reasons for the variable grade of inflammation we observed in our patients.

Effects of intravitreal ranibizumab on the untreated eye and systemic gene expression profile in age-related macular degeneration

The purpose of this study was to evaluate the systemic effects of intravitreal ranibizumab (Lucentis) treatment in patients with neovascular age-related macular degeneration (AMD). The impact of intravitreal ranibizumab injections on central retinal thickness (CRT) of treated and contralateral untreated eyes, and differences in gene expression patterns in the peripheral blood mononuclear cells were analyzed. The study included 29 patients aged 50 years old and over with diagnosed neovascular AMD. The treatment was defined as 0.5 mg of ranibizumab injected intravitreally in the form of one injection every month during the period of 3 months. CRT was measured by optical coherence tomography. The gene expression profile was assigned using oligonucleotide microarrays of Affymetrix HG-U133A. Studies have shown that there was a change of CRT between treated and untreated eyes, and there were differences in CRT at baseline and after 1, 2, and 3 months of ranibizumab treatment. Three months after intravitreal injection, mean CRT was reduced in the treated eyes from 331.97±123.62 to 254.31±58.75 μm, while mean CRT in the untreated fellow eyes reduced from 251.07±40.29 to 235.45±36.21 μm at the same time. Furthermore, the research has shown that among all transcripts, 3,097 expresses change after the ranibizumab treatment in relation to controls. Among these transcripts, 1,339 were up-regulated, whereas 1,758 were down-regulated. Our results show the potential systemic effects of anti-VEGF therapy for AMD. Moreover, our study indicated different gene expression in peripheral blood mononuclear cells before and after intravitreal ranibizumab treatment.

Effects of three consecutive monthly intravitreal injection of ranibizumab for polypoidal choroidal vasculopathy in Korea

AIM

To evaluate the efficacy and safety of three consecutive monthly injections of intravitreal ranibizumab for the treatment of polypoidal choroidal vasculopathy (PCV) in Korea.

METHODS

A retrospective chart review of 25 patients (27 eyes) with PCV was conducted. Patients received three initial monthly intravitreal injections (0.5 mg) of ranibizumab and were monitored monthly for 12mo between January 2010 and October 2011. Reinjection of ranibizumab after three initial monthly loading was administered on an as-needed basis, guided by the optical coherence tomography (OCT), fluorescein angiography (FA) and indocyanine green angiography (ICGA). The main outcomes were the changes of the mean best corrected Snellen visual acuity (VA), central macular thickness (CMT) by OCT, the changes of polyps and branching vascular network by FA and ICGA, and total number of injections received by patients during the 12mo.

RESULTS

The mean best corrected Snellen visual acuities at baseline, 1, 3, 6 and 12mo after primary injection were 0.77±0.59, 0.76±0.53, 0.70±0.47, 0.63±0.43, 0.61±0.43, 0.62±0.42 logMAR, respectively, and showed significant improvement at 3, 6, 12mo (P=0.003, P=0.002, P=0.018, Wilcoxon signed-rank test). The mean CMT at baseline, 1, 2, 3, 6, and 12mo was 312.41±66.38 µm, 244.59±71.47 µm, 232.32±69.41 µm, 226.69±69.03 µm, 228.62±37.07 µm, 227.59±51.01 µm respectively, and showed significant reduction (all P<0.001, Wilcoxon signed-rank test). Polypoidal lesions resolved on ICGA in 3 eyes (11.1%) and a branching vascular network remained in all 24 eyes (88.9%). A total of 106 injections were given in the 12-month period, which equaled to a mean of 3.92 (range, 3-6) times. Sixteen of the 27 treated eyes had additional 1.56±0.91 injections. The others (11 eyes) had just 3 consecutive injections.

CONCLUSION

An initial loading dose of three monthly ranibizumab injections is a safe and effective method in treating PCV, with visual and anatomical improvement over one year follow-up.

One-year outcome of two different initial dosing regimens of intravitreal ranibizumab for myopic choroidal neovascularization

PURPOSE

To evaluate and compare the 12-month outcomes of two different initial dosing regimens of intravitreal ranibizumab for myopic choroidal neovascularization (CNV).

METHODS

We retrospectively reviewed the medical records of 46 consecutive, treatment-naive eyes which received intravitreal ranibizumab for subfoveal and juxtafoveal CNV secondary to pathologic myopia with a follow-up of 12 months. Two groups were created according to different initial dosing regimens: group 1 included 25 eyes treated by a single intravitreal injection; group 2 included 21 eyes treated by three consecutive monthly injections. Additional injections were performed if needed. Patients' demographic data, best-corrected visual acuity (BCVA), recurrence of CNV and total number of treatments were recorded and evaluated.

RESULTS

There was no significant difference between two groups among baseline demographic data. At 12 months, the mean logMAR BCVA improved from 0.58 to 0.23 in group 1 and from 0.55 to 0.22 in group 2 (both p < 0.001; Wilcoxon signed-rank test). The mean logMAR BCVA at 12 months did not differ significantly. The average number of injections was 2.32 (SD 1.22) in group 1 and 3.57 (SD 1.12) in group 2 (p = 0.001; two-tailed t-test). During the follow-up, 17 of 25 eyes in group 1 and 5 of 21 eyes in group 2 received additional injections (p = 0.004).

CONCLUSIONS

Similar visual improvement was achieved in both groups. Although the eyes with a loading dose of 3 monthly injections required a higher number of total injections over 1 year, there was a much lower rate of retreatment needed.

The effects of intravitreal bevacizumab in infectious and noninfectious uveitic macular edema

Background/Aims. To assess the effect of intravitreal bevacizumab injection (IVBI) for the treatment of macular edema due to infectious and noninfectious uveitides. Design. Retrospective interventional case series. Methods. A chart review was performed on all the patients who were diagnosed with uveitic macular edema (UME) and received 1.25 mg of IVBI at two referral centers in Riyadh, Saudi Arabia. All included patients had their visual acuity and macular thickness analyzed at baseline and at 1 and 3 months following IVBI and any sign of reactivation was noted. Results. The mean age of patients was 41 ± 16 years with a mean followup of 4 ± 1 months. Ten patients had idiopathic intermediate uveitis, 9 patients had Behcet's disease, 10 had idiopathic panuveitis, and twelve patients had presumed ocular tuberculosis uveitis. Following IVBI, the mean LogMAR visual acuity improved from 0.8 ± 0.8 at baseline to 0.4 ± 0.5 at 1 month and 0.3 ± 0.5 at 3 months (P < 0.002, at 3 months). The mean macular thickness was 430 ± 132 μm at baseline. Following IVBI macular thickness improved to 286 ± 93 μm at 1 month and to 265 ± 88 μm at 3 months of followup (P < 0.001, at 3 months). Conclusion. Bevacizumab was effective in the management of UME associated with both infectious and noninfectious uveitides. Intravitreal bevacizumab induced remission of UME with infectious uveitis and had no immunosuppressive effect against infectious agents.

Vascular endothelial growth factor signaling in hypoxia and inflammation

Infection, cancer and cardiovascular diseases are the major causes for morbidity and mortality in the United States according to the Center for Disease Control. The underlying etiology that contributes to the severity of these diseases is either hypoxia induced inflammation or inflammation resulting in hypoxia. Therefore, molecular mechanisms that regulate hypoxia-induced adaptive responses in cells are important areas of investigation. Oxygen availability is sensed by molecular switches which regulate synthesis and secretion of growth factors and inflammatory mediators. As a consequence, tissue microenvironment is altered by re-programming metabolic pathways, angiogenesis, vascular permeability, pH homeostasis to facilitate tissue remodeling. Hypoxia inducible factor (HIF) is the central mediator of hypoxic response. HIF regulates several hundred genes and vascular endothelial growth factor (VEGF) is one of the primary target genes. Understanding the regulation of HIF and its influence on inflammatory response offers unique opportunities for drug development to modulate inflammation and ischemia in pathological conditions.

A meta-analysis of anti-vascular endothelial growth factor remedy for macular edema secondary to central retinal vein occlusion

Background

Central retinal vein occlusion (CRVO) associates with severe vision outcome and no proven beneficial treatment. Our meta-analysis intended to appraise the efficacy and safety of anti-vascular endothelial growth factor (anti-VEGF) agents in macular edema (ME) following CRVO.

Methods

Data were collected and analyzed by Review Manager 5.2.1. We employed a random-effects model to eliminate between-study heterogeneity. N_fs (called fail-safe number) was calculated to evaluate the publication bias.

Results

We included 5 trials consisting 323 cases and 281 controls. Primary outcomes showed that overall comparison of anti-VEGF agents with placebo control yielded a 374% and 136% increased tendency for a gain of 15 letters or more on Early Treatment Diabetic Retinopathy Study (ETDRS) chart (95% confidence interval [95% CI]: 2.43–9.23; P<0.00001; I² = 59%, 95% CI: 1.60–3.49; P<0.0001; I² = 0%, respectively) at 6 and 12 months. Secondary outcomes showed that a 90% and 77% decreased risk at 6 and 12 months for a loss of 15 letters or more. The overall mean difference showed a statistically significance in best-corrected visual acuity (BCVA) on each time point. However, changes of central retinal thickness (CRT) lost significance at 12 months after 6-month as-needed treatment. The incidence of adverse events (AEs) had no statistical difference between anti-VEGF and placebo groups. Subgroup analyses indicated that patients receiving Aflibercept got the highest tendency to gain 15 letters or more (OR = 9.78; 95% CI: 4.43–21.56; P<0.00001). Age controlled analysis suggested a weaken tendency of BCVA improvement in age over 50 (MD = 12.26; 95% CI: 7.55–16.98; P<0.00001). Subgroup analysis by clinical classification showed a strengthen difference of BCVA changes at 6 months in ischemic type (MD = 19.65 letters, 95% CI: 13.15 to 26.14 letters, P<0.00001).

Conclusions

Our results showed that anti-VEGF agents were superior to placebo in CRVO-ME treatment with no statistically significant AEs, especially in younger people and for ischemic type.

Bevacizumab for macular edema secondary to retinal vein occlusion: a systematic review and meta-analysis

PURPOSE

To assess the effect and safety of using single intravitreal bevacizumab (IVB) versus intravitreal triamcinolone acetonide (IVTA) and grid laser photocoagulation (GLP), or a combination of IVB and IVTA for treatment of retinal vein occlusion (RVO)-associated macular edema, mainly exploring its effects on visual acuity (VA) and central macular thickness (CMT).

METHODS

Eligible studies were identified via searching databases, including Medline (PubMed), Web of Science, and the Cochrane Library, without status or other limits up to June 2012.

SELECTION CRITERIA

We include randomized clinical control trials comparing 1.25 mg IVB injection with other treatment strategies, including a 4 mg IVTA injection or GLP or a combination of 1.25 mg IVB and 2 mg IVTA injection, for patients with RVO-associated macular edema. Eligible studies should report both VA and CMT outcomes, and with a minimum follow-up of 4 weeks. Results: Two authors assessed the trial quality and extracted data independently.

MAIN RESULTS

Four studies were included in this study. Comparing to IVTA and GLP, IVB was more effective in improving VA at 1 month (weighted mean difference [WMD], -0.07; 95% confidence interval [CI], -0.10 to -0.05; P<0.00001), 3 months (WMD, -0.24; 95% CI, -0.28 to -0.20; P<0.00001), and 6 months during the follow-up (WMD, -0.17; 95% CI, -0.21 to -0.13; P<0.00001) in patients with RVO-associated macular edema. There was no statistical significance in reducing CMT values throughout the periods. Compared with IVB/IVTA combination, VA improvement became statistically significant at 3 months of follow-up (WMD, -0.26; 95% CI, -0.29 to -0.23; P<0.00001), while no statistical significance was found in both VA values at 1 month of follow-up and CMT values throughout the periods. The occurrence of intraocular pressure (IOP) was much lower in IVB groups.

CONCLUSIONS

IVB is effective in treating patients with RVO-associated macular edema; especially if it has distinct effects, of which, VA could be improved to the utmost extent as well as by the earliest of time. IVB is also effective in decreasing CMT, but without any significant advantages over IVTA or GLP. Furthermore, IVB seems to be safer than IVTA in consideration of IOP increase.

Retinal vasculitis in two pediatric patients with systemic lupus erythematosus: a case report

We report two pediatric female patients with systemic lupus erythematosus (SLE) who presented with decreased vision. Both patients were found to have retinal vasculitis and occlusive disease. The first patient also presented with vitreous hemorrhage and later non-arteritic ischemic optic neuropathy. She was treated with panretinal photocoagulation and steroid therapy and later in her disease course was treated with rituximab and cyclophosphamide. Her vision remained decreased. The second patient was treated with rituximab and monthly cyclophosphamide infusions early in her disease course, and her vision improved dramatically. The difference in the presentations and outcomes of these two pediatric patients with SLE highlights the spectrum of severity of SLE retinopathy. We suggest that early recognition of disease and early intervention with B-cell depletion therapy in addition to a traditional cytotoxic agent should be considered in pediatric patients with SLE and occlusive retinopathy.

Retinal toxicity of intravitreal trastuzumab in a rabbit model: preliminary results of an experimental study

PURPOSE

To evaluate the retinal toxicity of intravitreal trastuzumab in a rabbit model.

METHODS

Fourteen New Zealand albino rabbits, weighing between 2.5 and 3 kg were used for this study. In the first group (n=6), 0.1 mL trastuzumab 10 mg/mL was injected into the vitreous. In the second group (n=6), the same volume of sterile balanced saline solution was injected intravitreally (sham injection). Additionally, 0.1 mL of 2 other concentrations of trastuzumab (7.5 and 5 mg/mL, respectively), was injected into the vitreous of 2 rabbits. Slit-lamp and funduscopic examinations were performed and the animals were observed for 2 weeks for signs of inflammation, infection, and toxicity. An electroretinogram (ERG) was performed at baseline and 14 days after the injection. The animals were killed on day 14 and a histological examination was performed in the enucleated eyes.

RESULTS

The clinical examination was unremarkable on either sham or intravitreal injection of trastuzumab. Conversely, the ERG was greatly affected and in 2 cases extinguished 14 days after trastuzumab injection. Consistent with electrophysiological abnormalities of the retina, signs of retinal edema in experimented eyes, suggesting morphologic retinal damage, were observed. In contrast, in the sham injected eyes, the ERG was normal without histopathologic retinal changes.

CONCLUSIONS

Intravitreal trastuzumab seems to be toxic to the retina in albino rabbits even at a concentration of 5 mg/mL. Further studies are needed to evaluate the safety of intravitreal trastuzumab in models of choroidal neovascularization, as well as to obtain experience concerning the intravitreal toxicity of trastuzumab in primates too and not only in rabbits.

Single intravitreal ranibizumab injection for optic disc neovascularisation due to possibly traumatic, direct carotid cavernous fistula

We report a patient with optic disc neovasculariation due to possibly traumatic direct carotid cavernous fistula treated by a single dose of intravitreal ranibizumab prior to neurointervention. A 25-year-old man had a 10-month history of bilateral proptosis and left sixth nerve paralysis was evaluated. Conjunctival vessels were markedly dilated, especially in the left eye. Clinical examination and fundus fluorescein angiography revealed disc neovascularisation in the left eye with subtle peripheral retinal ischaemia. Magnetic resonance imaging suggested a high-flow carotid cavernous fistula on the left side and this was confirmed by catheter angiography. A single dose of intravitreal ranibizumab was injected prior to neuro-intervention. The disc neovascularisation regressed completely three days later. The left direct carotid cavernous fistula was later treated successfully with coil embolisation. Optic disc neovascularisation is a very rare feature of carotid cavernous fistula and intravitreal ranibizumab may be a useful therapeutic adjunct prior to neuro-interventional techniques to reduce neovascularisation-induced haemorrhage following the intervention.

Characterization of human sclera barrier properties for transscleral delivery of bevacizumab and ranibizumab

The objectives of this study were to (a) investigate transscleral permeation of antivascular endothelial growth factor drugs bevacizumab and ranibizumab and (b) examine the effects of molecular structures of macromolecules upon permeation across human sclera using bevacizumab, ranibizumab, fluorescein isothiocyanate (FITC)-labeled bovine serum albumin (FITC-BSA), FITC-labeled ficoll (FITC-ficoll), and FITC-labeled dextrans (FITC-dextrans) in vitro. The hydrodynamic radii of the macromolecules were measured using dynamic light scattering, their partition coefficients to sclera were determined in uptake experiments, and their permeability coefficients and transport lag times across sclera were evaluated in transport experiments of side-by-side diffusion cells. Macromolecules showed relatively low partition coefficients to sclera. The partition coefficient of FITC-BSA was found to be related to its concentration in the equilibration solution, whereas for other macromolecules, no specific concentration dependency was observed. The macromolecules displayed relatively low permeability coefficients and long transport lag times because of their molecular sizes and hindered diffusion. Bevacizumab, ranibizumab, and FITC-BSA exhibited lower transscleral permeability and longer transport lag times than FITC-dextrans and FITC-ficoll of comparable molecular weights possibly because of the flexible structures of the polysaccharides. Thus, the polysaccharides may not be good surrogate permeants to model transscleral transport of therapeutic proteins in transscleral delivery studies.

An anti-angiogenic reverse thermal gel as a drug-delivery system for age-related wet macular degeneration

Reverse thermal gels have numerous biomedical implications, as they undergo physical gelation upon temperature increases and can incorporate biomolecules to promote tissue repair. Such a material is developed for the sustained release of bevacizumab (Avastin), a drug used to treat age-related macular degeneration. The polymer, poly(ethylene glycol)-poly(serinol hexamethylene urethane) (ESHU), forms a physical gel when heated to 37 °C and shows good cytocompatibility with ocular cells. ESHU is capable of sustaining bevacizumab release over 17 weeks in vitro, and the release kinetics can be altered by changing the drug dose and the ESHU concentration. These results suggest that ESHU is biologically safe, and suitable for ocular drug delivery.

Prevention of VEGF-induced growth and tube formation in human retinal endothelial cells by aldose reductase inhibition

OBJECTIVE

Since diabetes-induced vascular endothelial growth factor (VEGF) is implicated in retinal angiogenesis, we aimed to examine the role of aldose reductase (AR) in VEGF-induced human retinal endothelial cells (HREC) growth and tube formation.

MATERIALS AND METHODS

HRECs were stimulated with VEGF and cell-growth was determined by MTT assay. AR inhibitor, fidarestat, to block the enzyme activity and AR siRNA to ablate AR gene expression in HREC were used to investigate the role of AR in neovascularization using cell-migration and tube formation assays. Various signaling intermediates and angiogenesis markers were assessed by Western blot analysis. Immuno-histochemical analysis of diabetic rat eyes was performed to examine VEGF expression in the retinal layer.

RESULTS

Stimulation of primary HREC with VEGF caused increased cell growth and migration, and AR inhibition with fidarestat or ablation with siRNA significantly prevented it. VEGF-induced tube formation in HREC was also significantly prevented by fidarestat. Treatment of HREC with VEGF also increased the expression of VCAM, AR, and phosphorylation and activation of Akt and p38-MAP kinase, which were prevented by fidarestat. VEGF-induced expression of VEGFRII in HREC was also prevented by AR inhibition or ablation.

CONCLUSIONS

Our results indicate that inhibition of AR in HREC prevents tube formation by inhibiting the VEGF-induced activation of the Akt and p38-MAPK pathway and suggest a mediatory role of AR in ocular neovascularization generally implicated in retinopathy and AMD.

The relative clinical effectiveness of ranibizumab and bevacizumab in diabetic macular oedema: an indirect comparison in a systematic review

OBJECTIVE

To indirectly compare the effectiveness of ranibizumab and bevacizumab in the treatment of diabetic macular oedema.

DESIGN

Systematic review and indirect comparison.

DATA SOURCES

Medline (1996-September 2011), Embase (1996-September 2011), and the Cochrane Central Register of Controlled Trials (Issue 4, 2011).

SELECTION CRITERIA FOR STUDIES

Randomised trials evaluating ranibizumab or bevacizumab in diabetic macular oedema with a common comparator and sufficient methodological similarity to be included within an indirect comparison were eligible for inclusion.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of patients with an improvement in best corrected visual acuity of more than two lines on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Secondary outcomes included mean changes in best corrected visual acuity and in central macular thickness, and adverse events. Best corrected visual acuity was converted to logMAR units, a linear scale of visual acuity with positive values representing increasing visual loss. Indirect comparisons were done using Bayesian methods to estimate relative treatment effects of bevacizumab and ranibizumab.

RESULTS

Five randomised controlled trials with follow-up of 6-12 months and a common comparator (multiple laser treatment) were sufficiently similar to be included in the indirect comparison. Generally studies were small, resulting in wide credible intervals. The proportions of patients with an improvement in best corrected visual acuity of >2 lines were 21/77 participants (27%) for bevacizumab and 60/152 participants (39%) for ranibizumab (odds ratio 0.95 (95% credible interval 0.23 to 4.32)). The wide credible intervals cannot exclude a greater improvement, or worse outcome, for either drug. The mean change in best corrected visual acuity non-significantly favoured bevacizumab (treatment effect -0.08 logMAR units (-0.19 to 0.04)). The difference in mean change in central macular thickness was not statistically significant between ranibizumab and bevacizumab (treatment effect -6.9 μm (-88.5 to 65.4)).

CONCLUSIONS

Results suggest no difference in effectiveness between bevacizumab and ranibizumab, but the wide credible intervals cannot exclude the possibility that either drug might be superior. Sufficiently powered, direct head to head trials are needed.

Effect of intravitreal anti-vascular endothelial growth factor therapy on the risk of arterial thromboembolic events: a meta-analysis

BACKGROUND

Intravitreal anti-vascular endothelial growth factor (VEGF) monoclonal antibodies are used in ocular neovascular diseases. A consensus has emerged that intravenous anti-VEGF can increase the risk of arterial thromboembolic events. However, the role of intravitreal anti-VEGF in arterial thromboembolism is controversial. Therefore, we did a systematic review and meta-analysis to investigate the effects of intravitreal anti-VEGF on the risk of arterial thromboembolic events.

METHODS

Electronic databases were searched to identify relevant randomized clinical trials comparing intravitreal anti-VEGF with controls. Criteria for inclusion in our meta-analysis included a study duration of no less than 12 months, the use of a randomized control group not receiving any intravitreal active agent, and the availability of outcome data for arterial thromboembolic events, myocardial infarction, cerebrovascular accidents, and vascular death. The risk ratios and 95% CIs were calculated using a fixed-effects or random-effects model, depending on the heterogeneity of the included studies.

RESULTS

A total of 4942 patients with a variety of ocular neovascular diseases from 13 randomized controlled trials were identified and included for analysis. There was no significant difference between intravitreal anti-VEGF and control in the risk of all events, with risk ratios of 0.87 (95% CI, 0.64 to 1.19) for arterial thromboembolic events, 0.96 (95% CI, 0.55-1.68) for cerebrovascular accidents, 0.69 (95% CI 0.40-1.21) for myocardial infarctions, and 0.68 (95% CI, 0.37-1.27) for vascular death.

CONCLUSIONS

The strength evidence suggests that the intravitreal use of anti-VEGF antibodies is not associated with an increased risk of arterial thromboembolic events.

Mechanisms of age-related macular degeneration

Age-related macular degeneration (AMD), a progressive condition that is untreatable in up to 90% of patients, is a leading cause of blindness in the elderly worldwide. The two forms of AMD, wet and dry, are classified based on the presence or absence of blood vessels that have disruptively invaded the retina, respectively. A detailed understanding of the molecular mechanisms underlying wet AMD has led to several robust FDA-approved therapies. In contrast, there are no approved treatments for dry AMD. In this review, we provide insight into the critical effector pathways mediating each form of the disease. A recurring theme that spans most aspects of AMD pathogenesis is defective immune modulation in the classically immune-privileged ocular haven. Interestingly, the latest advances in AMD research also highlight common molecular disease pathways with other neurodegenerative disorders. Finally, the therapeutic potential of intervening at known mechanistic steps of AMD pathogenesis is discussed.

Evaluation of pain in intravitreal bevacizumab injections

PURPOSE

To evaluate the correlation between pain associated with intravitreal bevacizumab injection and the location of the injection.

METHODS

The study included 218 eyes of 218 patients, who received an intravitreal bevacizumab injection at our institution. Pain was measured by the Visual Analog Scale (VAS). Additional parameters recorded included age, sex, indication for the injection, injection site by quadrant, number injections in the study eye, presence of diabetes mellitus, and lens status.

RESULTS

Indications for injection included age-related macular degeneration (69.7%), diabetic macular edema (13.3%), neovascularization due to proliferative diabetic retinopathy (6.9%), and cystoid macular edema secondary to retinal vascular occlusions (10.1%). Pain scores on the VAS ranged from 0 to 84, with a mean of 17.4 ± 17.1. Pain did not correlate significantly with any of the recorded parameters, but a trend was found toward less pain associated with injection in the lower-left quadrant (p = 0.067).

CONCLUSIONS

This is the largest series studying the pain associated with intravitreal injections and provides a thorough description of the pain associated with this procedure. Since there is no anatomical difference between quadrants, we assume the demonstrated trend indicates that less pain is associated with the location in which it is most convenient for the ophthalmologist to perform the injection.

Pharmacokinetic rationale for dosing every 2 weeks versus 4 weeks with intravitreal ranibizumab, bevacizumab, and aflibercept (vascular endothelial growth factor Trap-eye)

PURPOSE

Monthly dosing with inhibitors of vascular endothelial growth factor (VEGF) results in stable or improved visual acuity in most patients with neovascular age-related macular degeneration. However, a minority of patients show little if any response to therapy with persistent or worsening macular fluid. Pharmacokinetic modeling was performed to determine if more frequent dosing with anti-VEGF drugs could be theoretically beneficial.

METHODS

A mathematical model comparing the time-dependent relative binding activities of ranibizumab, bevacizumab, and aflibercept (VEGF Trap-eye; VTE) was used to determine the theoretical peak and trough binding activities when the drugs were injected every 14 days and every 28 days. The intravitreal half-lives of ranibizumab, bevacizumab, and the VTE were estimated to be 3.2, 5.6, and 4.8 days, respectively. The relative molar binding activities of ranibizumab, bevacizumab, and the VTE used in the analyses were 1, 0.05 to 0.2, and 140, respectively. The expected peak and trough binding activities for ranibizumab, bevacizumab, and VTE were calculated. Dosing every 2 weeks was performed on selected patients who had a poor response to monthly therapy.

RESULTS

Dosing of a drug every 2 weeks resulted in markedly improved trough binding activity, but had little impact on the peak binding activity when calculated through Day 28. The dosing of bevacizumab every 2 weeks resulted in trough binding levels that were superior to monthly dosing with ranibizumab at a dose of 0.5 mg and potentially superior to the levels achieved when ranibizumab was dosed monthly at a dose of 2.0 mg. The VTE displayed superior binding levels for both peak and trough levels even when compared with ranibizumab doses given every 2 weeks. Two case reports demonstrate the clinical usefulness of dosing with anti-VEGF therapy every 2 weeks in eyes with VEGF-dependent macular fluid appearing to be refractory to monthly dosing.

CONCLUSION

The theoretical increase in trough binding levels when anti-VEGF drugs are dosed every 2 weeks most likely explains the clinical benefit observed in patients who received biweekly injections after their poor response to monthly therapy. The short-term use of biweekly dosing may be an attractive treatment option for those eyes that show a treatment response within 2 weeks of an injection, but rebound with increased macular fluid after a month. In the future, VTE should provide higher trough levels of anti-VEGF binding activity and eliminate the need for biweekly dosing in those eyes with VEGF-mediated exudation that appear unresponsive to monthly ranibizumab or bevacizumab.

Intravitreal anti-vascular endothelial growth factor therapy for choroidal neovascularization secondary to ocular histoplasmosis syndrome

BACKGROUND

Intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is beneficial in treating choroidal neovascularization from age-related macular degeneration, but few long-term studies have shown its efficacy in choroidal neovascularization from ocular histoplasmosis syndrome. Intravitreal anti-VEGF therapy may be effective in cases of choroidal neovascularization because of ocular histoplasmosis syndrome.

METHODS

Retrospective chart review of 54 eyes treated with intravitreal anti-VEGF therapy for choroidal neovascularization in ocular histoplasmosis syndrome with >1 year of follow-up after initiation of anti-VEGF treatment was performed. Previous treatment and demographic information were recorded. Visual acuity was recorded for each injection treatment and at the last follow-up visit. The anti-VEGF agent was recorded for each injection treatment. Visual acuity was recorded at the last follow-up visit.

RESULTS

Mean visual acuity improved from 20/53 to 20/26 over an average of 26.8 months. Either bevacizumab or ranibizumab were administered on an average of 4.5 injections per patient per year of follow-up. Vision loss was seen in only three eyes with loss limited to a single line of vision. Patients experienced no serious complications from treatment.

CONCLUSION

Long-term intravitreal anti-VEGF therapy with bevacizumab or ranibizumab is beneficial in treatment of choroidal neovascularization in ocular histoplasmosis syndrome.

Genetic predictors of response to photodynamictherapy

In Western countries, therapeutic management of patients affected by choroidal neovascularization (CNV) secondary to different typologies of macular degeneration represents a major health care problem. Age-related macular degeneration is the disease most frequently associated with CNV development. Schematically, CNVs can be distinguished into classic and occult subtypes, which are characterized by variable natural history and different responsiveness to some therapeutic procedures. At present, the dramatic vision loss due to CNV can be mainly treated by two interventional strategies, which are utilizable in either single or combined modalities: photodynamic therapy with verteporfin (PDT-V), and intravitreal administration of drugs acting against vascular endothelial growth factor. The combined use of PDT-V and anti-angiogenic drugs represents one of the most promising strategies against neovascular macular degeneration, but it unavoidably results in an expensive increase in health resource utilization. However, the positive data from several studies serve as a basis for reconsidering the role of PDT-V, which has undergone a renaissance prompted by the need for a more rational therapeutic approach toward CNV. New pharmacogenetic knowledge of PDT-V points to exploratory prospects to optimize the clinical application of this intriguing photothrombotic procedure. In fact, a Medline search provides data regarding the role of several single nucleotide polymorphisms (SNPs) as genetic predictors of CNV responsiveness to PDT-V. Specifically, correlations between SNPs and different levels of PDT-V efficacy have been detected by examining the gene variants influencing (i) thrombo-coagulative pathways, i.e. methylenetetrahydrofolate reductase (MTHFR) 677C>T (rs1801133), factor V (F5) 1691G>A (rs6025), prothrombin (F2) 20210G>A (rs1799963), and factor XIII-A (F13A1) 185G>T (rs5985); (ii) complement activation and/or inflammatory processes, i.e. complement factor H (CFH) 1277T>C (rs1061170), high-temperature requirement factor A1 (HTRA1) promoter -512G>A (rs11200638), and two variants of the C-reactive protein (CRP) gene (rs2808635 and rs876538); and (iii) production and bioavailability of vascular endothelial growth factor (VEGFA -2578C>A [rs699947] and rs2146323). This article critically evaluates both the clinical plausibility and the opportunity to utilize the most important SNP-response interactions of PDT-V for an effective upgrade of the current anti-CNV therapeutic scenario. In addition, the pharmacogenetics of a very severe post-PDT-V adverse event, i.e. a decrease in acute vision, is briefly discussed. A comprehensive appraisal of the findings reviewed in this article should be carefully considered to design future trials aimed at verifying (after proper genotypic stratification of the enrolled patients) whether these innovative pharmacogenetic approaches will be able to improve the multifaceted interventional management of neovascular macular degeneration.

The movement of self-assembled amphiphilic polymeric nanoparticles in the vitreous and retina after intravitreal injection

The purpose of this study is to determine the correlation between the distribution of nanoparticles in the vitreous and retina and their surface properties after intravitreal injection. For this purpose, we synthesized seven kinds of nanoparticles through self-assembly of amphiphilic polymer conjugates in aqueous condition. They showed similar size but different surface properties. They were labeled with fluorescent dyes for efficient tracking. After intravitreal injection of these nanoparticles into a rodent eye, their time-dependent distribution in the vitreous and retina was determined in stacking tissue images by confocal microscopy. The results demonstrated that the surface property of nanoparticles is a key factor in determining their distribution in the vitreous and retina after intravitreal injection. In addition, immunohistochemistry and TEM images of retina tissues suggested the important mechanism related with Mülller cells for intravitreally administered nanoparticles to overcome the physical barrier of inner limiting membrane and to penetrate into the deeper retinal structures. Therefore, we expect that this study can provide valuable information for biomedical researchers to develop optimized nanoparticles as drug or gene carriers for retinal and optic nerve disorders such as glaucoma, age-related macular degeneration, and diabetic retinopathy.

Adeno-associated virus mediated gene therapy for retinal degenerative diseases

Retinal gene therapy holds great promise for the treatment of inherited and noninherited blinding diseases such as retinitis pigmentosa and age-related macular degeneration. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV) because it mediates long-term transgene expression in a variety of retinal cell types and elicits minimal immune responses. Inherited retinal diseases are nonlethal and have a wide level of genetic heterogeneity. Many of the genes have now been identified and their function elucidated, providing a major step towards the development of gene-based treatments. Extensive preclinical evaluation of gene transfer strategies in small and large animal models is key to the development of successful gene-based therapies for the retina. These preclinical studies have already allowed the field to reach the point where gene therapy to treat inherited blindness has been brought to clinical trial.In this chapter, we focus on AAV-mediated specific gene therapy for inherited retinal degenerative diseases, describing the disease targets, the preclinical studies in animal models and the recent success of the LCA-RPE65 clinical trials.

Long-term effectiveness of intravitreal bevacizumab for choroidal neovascularization secondary to angioid streaks in pseudoxanthoma elasticum

PURPOSE

To investigate the long-term effectiveness of intravitreal bevacizumab for treating active choroidal neovascularizations in pseudoxanthoma elasticum (PXE).

METHODS

Fourteen patients (16 eyes) received intravitreal bevacizumab (1.5 mg) and were investigated monthly. Further treatments were administered depending on disease activity. Examinations included best-corrected visual acuity, biomicroscopy, optical coherence tomography, fluorescein angiography and indocyanine green angiography, fundus autofluorescence, and digital fundus photography. Areas of atrophy of the retinal pigment epithelium and retinal fibrosis were quantified using semiautomated detection on fundus autofluorescence images.

RESULTS

Mean age of the cohort was 55 ± 13 years, and mean best-corrected visual acuity at baseline was 20/80 (logarithm of the minimum angle of resolution, 0.56, SD, 0.51). At last follow-up, after an average of 6.5 ± 5.7 injections over 28 months, best-corrected visual acuity was 20/40 (logarithm of the minimum angle of resolution, 0.31, SD, 0.32; P = 0.04). Central retinal thickness was reduced from 254 ± 45 μm to 214 ± 40 μm (P = 0.035). The size of retinal pigment epithelial atrophy and retinal fibrosis measured on fundus autofluorescence images increased in both the treated eye and the fellow eye (P < 0.05). Best-corrected visual acuity of patients with early disease compared with that of those with advanced disease improved significantly more over the treatment course (20/25 vs. 20/63; P = 0.008).

CONCLUSION

Intravitreal bevacizumab therapy demonstrates long-term effectiveness by preserving function in advanced disease and improving function in early disease. Best results of treating active choroidal neovascularizations in PXE are achieved when treatment starts the earliest possible.