Short-term topical bevacizumab in the treatment of stable corneal neovascularization

Detecting the corneal neovascularisation area using artificial intelligence

AIMS

To create and assess the performance of an artificial intelligence-based image analysis tool for the measurement and quantification of the corneal neovascularisation (CoNV) area.

METHODS

Slit lamp images of patients with CoNV were exported from the electronic medical records and included in the study. An experienced ophthalmologist made manual annotations of the CoNV areas, which were then used to create, train and evaluate an automated image analysis tool that uses deep learning to segment and detect CoNV areas. A pretrained neural network (U-Net) was used and fine-tuned on the annotated images. Sixfold cross-validation was used to evaluate the performance of the algorithm on each subset of 20 images. The main metric for our evaluation was intersection over union (IoU).

RESULTS

The slit lamp images of 120 eyes of 120 patients with CoNV were included in the analysis. Detections of the total corneal area achieved IoU between 90.0% and 95.5% in each fold and those of the non-vascularised area achieved IoU between 76.6% and 82.2%. The specificity for the detection was between 96.4% and 98.6% for the total corneal area and 96.6% and 98.0% for the non-vascularised area.

CONCLUSION

The proposed algorithm showed a high accuracy compared with the measurement made by an ophthalmologist. The study suggests that an automated tool using artificial intelligence may be used for the calculation of the CoNV area from the slit-lamp images of patients with CoNV.

Management of corneal neovascularization: Current and emerging therapeutic approaches

Corneal neovascularization (CoNV) is a sight-threatening condition affecting an estimated 1.4 million people per year, and the incidence is expected to rise. It is a complication of corneal pathological diseases such as infective keratitis, chemical burn, corneal limbal stem cell deficiency, mechanical trauma, and immunological rejection after keratoplasties. CoNV occurs due to a disequilibrium in proangiogenic and antiangiogenic mediators, involving a complex system of molecular interactions. Treatment of CoNV is challenging, and no therapy thus far has been curative. Anti-inflammatory agents such as corticosteroids are the mainstay of treatment due to their accessibility and well-studied safety profile. However, they have limited effectiveness and are unable to regress more mature neovascularization. With the advent of advanced imaging modalities and an expanding understanding of its pathogenesis, contemporary treatments targeting a wide array of molecular mechanisms and surgical options are gaining traction. This review aims to summarize evidence regarding conventional and emerging therapeutic options for CoNV.

Angiogenesis Model of Cornea to Understand the Role of Sphingosine 1-Phosphate

The bioactive sphingolipid sphingosine 1-phosphate (S1P) and its five cognate receptors (S1PR1-5) have been implicated to play important role in multiple aspects of human physiology and diseases. The S1P-S1PR1 signaling axis in endothelial cells is crucial for establishing flow competent blood vessels. The role of S1P in neovascular pathology is of great interest and is evolving as a promising target for treatment. Here we describe an easy and affordable in vivo model of corneal neovascularization using an alkali chemical burn to the cornea. This method gives a consistent and easy-to-quantitate procedure for neovascularization and angiogenesis studies.

An Update on Novel Ocular Nanosystems with Possible Benefits in the Treatment of Corneal Neovascularization

Corneal neovascularization (CNV) is an ocular pathological change that results from an imbalance between angiogenic factors and antiangiogenic factors as a result of various ocular insults, including infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation. Current clinical strategies for the treatment of CNV include pharmacological treatment and surgical intervention. Despite some degree of success, the current treatment strategies are restricted by limited efficacy, adverse effects, and a short duration of action. Recently, gene-based antiangiogenic therapy has become an emerging strategy that has attracted considerable interest. However, potential complications with the use of viral vectors, such as potential genotoxicity resulting from long-term expression and nonspecific targeting, cannot be ignored. The use of ocular nanosystems (ONS) based on nanotechnology has emerged as a great advantage in ocular disease treatment during the last two decades. The potential functions of ONS range from nanocarriers, which deliver drugs and genes to target sites in the eye, to therapeutic agents themselves. Various preclinical studies conducted to date have demonstrated promising results of the use of ONS in the treatment of CNV. In this review, we provide an overview of CNV and its current therapeutic strategies and summarize the properties and applications of various ONS related to the treatment of CNV reported to date. Our goal is to provide a comprehensive review of these considerable advances in ONS in the field of CNV therapy over the past two decades to fill the gaps in previous related reports. Finally, we discuss existing challenges and future perspectives of the use of ONS in CNV therapy, with the goal of providing a theoretical contribution to facilitate future practical growth in the area.

Ablation of Sphingosine Kinase 1 Protects Cornea from Neovascularization in a Mouse Corneal Injury Model

The purpose of this study was to investigate the role of sphingosine kinase 1 (SphK1), which generates sphingosine-1-phosphate (S1P), in corneal neovascularization (NV). Wild-type (WT) and Sphk1 knockout (Sphk1^−/−) mice received corneal alkali-burn treatment to induce corneal NV by placing a 2 mm round piece of Whatman No. 1 filter paper soaked in 1N NaOH on the center of the cornea for 20 s. Corneal sphingolipid species were extracted and identified using liquid chromatography/mass spectrometry (LC/MS). The total number of tip cells and those positive for ethynyl deoxy uridine (EdU) were quantified. Immunocytochemistry was done to examine whether pericytes were present on newly forming blood vessels. Cytokine signaling and angiogenic markers were compared between the two groups using multiplex assays. Data were analyzed using appropriate statistical tests. Here, we show that ablation of SphK1 can significantly reduce NV invasion in the cornea following injury. Corneal sphingolipid analysis showed that total levels of ceramides, monohexosyl ceramides (HexCer), and sphingomyelin were significantly elevated in Sphk^−/− corneas compared to WT corneas, with a comparable level of sphingosine among the two genotypes. The numbers of total and proliferating endothelial tip cells were also lower in the Sphk1^−/− corneas following injury. This study underscores the role of S1P in post-injury corneal NV and raises further questions about the roles played by ceramide, HexCer, and sphingomyelin in regulating corneal NV. Further studies are needed to unravel the role played by bioactive sphingolipids in maintenance of corneal transparency and clear vision.

Bevacizumab in High-Risk Corneal Transplantation: A Pilot Multicenter Prospective Randomized Control Trial

PURPOSE

To determine the efficacy of local (subconjunctival and topical) bevacizumab (Avastin) treatment in patients undergoing vascularized high-risk corneal transplantation.

DESIGN

Pilot, prospective, randomized, double-blind, placebo-controlled clinical trial conducted at 5 clinical centers in the United States, India, and Brazil.

PARTICIPANTS

Patients aged > 18 years undergoing high-risk penetrating keratoplasty, defined as corneal neovascularization (NV) in 1 or more quadrants ≥2 mm from the limbus or extension of corneal NV to the graft-host junction in a previously failed graft.

METHODS

Patients were randomized to receive subconjunctival bevacizumab (2.5 mg/0.1 ml) or placebo at the time of surgery, followed by topical bevacizumab (10 mg/ml) or topical placebo, administered 4 times per day for 4 weeks.

MAIN OUTCOME MEASURE

The 52-week endothelial immune rejection rate.

RESULTS

Ninety-two patients were randomized to receive bevacizumab (n = 48) or control (n = 44). The 52-week endothelial rejection rate was 10% in the bevacizumab group and 19% in the control group (P = 0.20). Post hoc, extended follow-up at the lead study site showed an endothelial rejection rate of 3% in the bevacizumab group and 38% in the control group (P = 0.003). Treatment with bevacizumab was found to have a hazard ratio of 0.15 (95% confidence interval, 0.03-0.65, P = 0.01) in a post hoc Cox regression analysis.

CONCLUSIONS

In patients undergoing vascularized high-risk corneal transplantation, there was no statistically significant difference in the rate of endothelial rejection at 1 year in the bevacizumab treatment group compared with the control group. This study may have been underpowered to detect a difference between treatment groups, and taken together, our data suggest that, in the current trial design, bevacizumab has a positive but not (yet) significant effect on endothelial rejection.

Topical bevacizumab for the treatment of corneal vascularization in dogs: A case series

Objective

To evaluate the effect and safety of topical anti‐human vascular endothelial growth factor bevacizumab in dogs with persistent corneal vascularization.

Animals studied

Prospective case series of 15 adult dogs (20 eyes).

Procedures

Dogs received 0.25% bevacizumab eye drops BID for 28 days. Follow‐ups were scheduled 28 days and 6–7 months after treatment start. Macroscopic findings were scored for conjunctival hyperemia, chemosis, ocular discharge, corneal edema, vascularization, and pigmentation. Vascularized area was assessed by analyzing photographs using an imaging software.

Results

The treatment response was variable. Some cases showed a marked reduction in vascularized area and edema, while other eyes had subtle signs of improvement. Vascularization score decreased from 1.5 to 1.1 and vascularized area was reduced by 48.8% after 28 days. A thinning of vessels, consolidation of areal bleedings into fine vascular networks, decrease in distal vessel branching, and a change from blurry vascularized beds into demarcated thin vessels were observed. One dog developed a SCCED 6 months after the last bevacizumab administration. Two dogs died 4 and 4.5 months after the last bevacizumab administration, aged 16 and 12 years, respectively. In all events, a causal relationship is unlikely but cannot be ruled out with certainty.

Conclusions

Our findings suggest that topical 0.25% bevacizumab may be an effective treatment option for corneal vascularization in dogs. Further long‐term placebo‐controlled studies with larger patient cohorts are recommended to provide scientific evidence of efficacy and to investigate dosage, safety, possible use as a single treatment, and routes of administration.

Update on Herpes simplex keratitis management

Herpes simplex keratitis (HSK) is a common, potentially blinding condition characterised by recurrent infections of the cornea, seen by both general ophthalmologists and corneal specialists. Successful treatment of recurrences reduces disease duration, prevents progressive corneal scaring leading to vision loss and reduces risk of further recurrences. In this review we discuss the relative advantages of the diagnostic laboratory investigations including polymerase chain reaction, viral culture and fluorescence-based immunohistochemistry. We review treatment strategies in selected aspects of HSK and discuss the management options in cases not responding to treatment.

Comparison of Topical Pigment Epithelium-Derived Factor (PEDF) with Topical Bevacizumab for Accelerating the Regression of Corneal Neovascularization in an Experimental Model of Rabbit Corneal Angiogenesis

Purpose: To evaluate the anti-angiogenic effect of topical administration of Pigment epithelium-derived factor (PEDF) on the reduction of corneal neovascularization (NV) in comparison to topical Bevacizumab.Methods: 18 eyes of 18 New Zealand rabbits were enrolled. Corneal NV was induced by a 7-0 silk suture. After suture removal, rabbits were randomly divided into three groups. In every group, one eye randomly treated with topical bevacizumab or topical PEDF or saline for 14 days. The area and length of neovascularization were measured by Image J. Histological studies were done in three groups.Results: After 14 days, the mean decrease of corneal NV length was 1.84 ± 0.17 mm (P < .001) in PEDF group and 1.6 ± 0.07 mm (P < .001) in bevacizumab group which was significantly more than the saline group (P = .001 and P < .001, respectively). There was no significant difference between PEDF and bevacizumab group in the reduction of corneal NV length (P = .85). The mean decrease of corneal NV area was 4.94 ± 0.55 mm² (P < .001) in PEDF group and 4.23 ± 0.29 mm² in the bevacizumab group (P < .001). PEDF and bevacizumab significantly decreased corneal NV area in comparison to the saline group (p = .017, p = .001, respectively). The mean decrease of corneal NV area did not show a significant difference between PEDF and bevacizumab groups (P = .72).Conclusion: Topical PEDF might be an effective and safe treatment option as bevacizumab in a short-term use, indicating that it is as good as the standard. However, long-term effect is required to be investigated.

Intrastromal bevacizumab in the management of corneal neovascularization: a retrospective review

PURPOSE

To evaluate the long-term safety and efficacy of intrastromal bevacizumab for treatment of deep corneal neovascularization in candidates for high-risk cornea grafting.

METHODS

A single-center retrospective study involving 14 eyes of 14 patients with chronic deep corneal neovascularization, treated with intrastromal bevacizumab by a single provider from 2011 to present. Intrastromal bevacizumab (0.05-0.1 mL of 2.5 mg/0.1 mL) was administered every 4-8 weeks. On average 1-3 intrastromal injections were performed prior to corneal grafting (penetrating keratoplasty or deep anterior lamellar keratoplasty).

RESULTS

64.2% patients had neurotrophic keratitis secondary to herpes zoster or simplex. Neovascularization was encroaching the visual axis in 50% and was paracentral in 42.8%. After intrastromal bevacizumab injection, 14.2% had complete regression of neovascularization, avoiding the need of future corneal transplant. Persistent neovascularization was noticed in 21.4%. Successful penetrating keratoplasty was performed in 57% of patients. Minimal adverse effects were noted; temporary epithelial defect was seen in two eyes and self-limited intrastromal hemorrhage in one. There was no evidence of recurrence of neovascularization or graft rejection in the transplant group (mean follow-up 3 years).

CONCLUSION

Intrastromal bevacizumab appears to be a safe and effective modality in the treatment of chronic corneal neovascularization, producing durable regression of corneal neovascularization and allowing for durable success of subsequent corneal transplants in high-risk patients.

Regression of corneal neovascularization: Adiponectin versus bevacizumab eye drops

PURPOSE

Comparing the effect of adiponectin versus bevacizumab in decreasing corneal neovascularization.

METHODS

This study was conducted on 30 eyes of 30 New Zealand Albino male rabbits. Corneal neovascularization was induced by a single 7-0 silk suture 2 mm long and 1 mm in front of the limbus for 2 weeks. Rabbits were randomly divided into three groups of adiponectin (20 µg/mL), bevacizumab (5 mg/mL) and artificial tears. The treatments continued up to 14 days.

RESULTS

At the end of 14 days, the average length of vessels in rabbits treated with adiponectin, bevacizumab and control groups decreased from 2.12 ± 0.32 mm to 0.89 ± 0.46 mm (57.68% ± 19.98%) (P < 0.001), 2.30 ± 0.41 mm to 1.30 ± 0.58 mm (42.49% ± 27.17%) (P = 0.048) and from 2.12 ± 0.44 mm to 1.81 ± 0.42 mm (14.81% ± 5.64%) (P = 0.112), respectively. The length of vessels decreased 57.68% ± 19.98% and 42.49% ± 27.17% in adiponectin versus bevacizumab groups, respectively (P = 0.527). The average surface area of vessels in rabbits treated with adiponectin, bevacizumab and control groups reduced from 5.02 ± 1.50 mm² to 1.40 ± 0.75 mm² (70.64% ± 17.76%) (P < 0.001) 0.34 ± 1.1 mm² to 2.80 ± 1.04 mm² (48.24% ± 19.23%) (P = 0.039) and 5.12 ± 2.92 mm² to 4.4 ± 2.55 mm² (14.68% ± 4.19%) (P = 0.117). Mean surface area of vascularization decreased 70.64% ± 17.76% and 48.24% ± 19.23% in adiponectin versus bevacizumab, respectively (P = 0.013).

CONCLUSIONS

The results of this study suggest that topical adiponectin can decrease recent corneal neovascularization.

Therapeutic Effects of a Novel Phenylphthalimide Analog for Corneal Neovascularization and Retinal Vascular Leakage

Purpose

Neovascularization (NV) and retinal vascular leakage are major causes of impaired vision in ocular diseases. The purpose of this study was to identify novel phenylphthalimide analogs with therapeutic effects on NV and vascular leakage and to explore the mechanism of action.

Methods

Antiangiogenic activities of novel phenylphthalimide analogs were assessed in vitro by using VEGF ELISA and endothelial cell proliferation assay. Their efficacies on retinal vascular leakage were evaluated using rat models of oxygen-induced retinopathy (OIR) and streptozotocin (STZ)-induced diabetes. The in vivo antiangiogenic activity was evaluated using topical administration in the alkali burn-induced corneal NV model. The expression of VEGF and intercellular adhesion molecule-1 (ICAM-1) were measured using ELISA.

Results

Thalidomide and three novel analogs all showed inhibitory effects on endothelial cell proliferation and VEGF expression in vitro. Through intravitreal injection, all of the compounds reduced retinal vascular leakage in the OIR and STZ-induced diabetic models. Among these compounds, (2,6-diisopropylphenyl)-5-amino-1H-isoindole-1,3-dione (DAID) displayed the most potent efficacy and reduced retinal vascular leakage in a dose-dependent manner in both the OIR and STZ-diabetes models. Topical administration of DAID also inhibited alkali burn-induced corneal NV. Furthermore, DAID attenuated the overexpression of VEGF and ICAM-1 in the retina of the OIR model. Intravitreal injection of DAID did not result in any detectable side effects, as shown by electroretinogram and retinal histological analysis.

Conclusions

DAID is a novel phenylphthalimide analog with potent effects on NV and retinal vascular leakage through downregulation of VEGF and inflammatory factors and has therapeutic potential.

Current and emerging therapies for corneal neovascularization

The cornea is unique because of its complete avascularity. Corneal neovascularization (CNV) can result from a variety of etiologies including contact lens wear; corneal infections; and ocular surface diseases due to inflammation, chemical injury, and limbal stem cell deficiency. Management is focused primarily on the etiology and pathophysiology causing the CNV and involves medical and surgical options. Because inflammation is a key factor in the pathophysiology of CNV, corticosteroids and other anti-inflammatory medications remain the mainstay of treatment. Anti-VEGF therapies are gaining popularity to prevent CNV in a number of etiologies. Surgical options including vessel occlusion and ocular surface reconstruction are other options depending on etiology and response to medical therapy. Future therapies should provide more effective treatment options for the management of CNV.

Cornea-Derived Mesenchymal Stromal Cells Therapeutically Modulate Macrophage Immunophenotype and Angiogenic Function

Macrophages are crucial drivers of inflammatory corneal neovascularization and thus are potential targets for immunomodulatory therapies. We hypothesized that therapeutic use of cornea-derived mesenchymal stromal cells (cMSCs) may alter the function of macrophages. We found that cMSCs can modulate the phenotype and angiogenic function of macrophages. In vitro, cMSCs induce apoptosis of macrophages while preferentially promoting a distinct CD14^hi CD16^hi CD163^hi CD206^hi immunophenotype that has significantly reduced angiogenic effects based on in vitro angiogenesis assays. In vivo, application of cMSCs to murine corneas after injury leads to reduced macrophage infiltration and higher expression of CD206 in macrophages. Macrophages cocultured ("educated") by cMSCs express significantly higher levels of anti-angiogenic and anti-inflammatory factors compared with control macrophages. In vivo, injured corneas treated with cMSC-educated macrophages demonstrate significantly less neovascularization compared with corneas treated with control macrophages. Knocking down the expression of pigment epithelial derived factor (PEDF) in cMSCs significantly abrogates its modulating effects on macrophages, as shown by the reduced rate of apoptosis, decreased expression of sFLT-1/PEDF, and increased expression of vascular endothelial growth factor-A in the cocultured macrophages. Similarly, cMSCs isolated from PEDF knockout mice are less effective compared with wild-type cMSCs at inhibiting macrophage infiltration when applied to wild-type corneas after injury. Overall, these results demonstrate that cMSCs therapeutically suppress the angiogenic capacity of macrophages and highlight the role of cMSC secreted PEDF in the modulation of macrophage phenotype and function. Stem Cells 2018;36:775-784.

Growth inhibition of formed corneal neovascularization following Fosaprepitant treatment

PURPOSE

The aim of this study was to test the efficacy of Neurokinin-1 Receptor (NK-1R) antagonist -Fosaprepitant- in inducing regression of established corneal neovascularization (CNV).

METHODS

Twenty C57BL/6 mice underwent alkali burn. Seven days later, when corneal neovessels had developed, they received Fosaprepitant 10 mg/ml, administered topically six times a day in the right eye for 10 days. In parallel, a group of 20 causticated mice was treated with normal saline, as control. A second independent experiment was also performed (n = 10/group). Finally, ten healthy mice received the same topical treatment for 10 days to evaluate Fosaprepitant safety. Haemangiogenesis and lymphangiogenesis were measured by means of vesselj plugin (imagej). Secondary endpoints, such as leucocyte infiltration, corneal opacity and corneal fluorescein staining were also evaluated. Inflammatory cell composition was assessed by flow cytometry. Differences between groups were assessed using unpaired t-test, Mann-Whitney U-test or two-way anova, as appropriate.

RESULTS

Topical Fosaprepitant administration induced a significant reduction of (i) CD31⁺ blood corneal neovessels (-27%, p = 0.0132), (ii) LYVE1⁺ lymphatic corneal neovessels (-31%, p = 0.0118) and (iii) CD45⁺ leucocyte infiltration (-36%; p = 0.0237). The second independent experiment confirmed these data. Moreover, Fosaprepitant-treated corneas showed a reduction in opacity, no impairment in corneal fluorescein staining and decreased infiltration of neutrophils (-72%, p < 0.05) and macrophages (-75%, p < 0.01). Finally, topical Fosaprepitant was not toxic to the ocular surface: no signs of conjunctivitis, opacity, perforations or corneal fluorescein staining were detected. Similarly, corneal TUJ1⁺ nerve density was not affected.

CONCLUSIONS

Our data suggest that NK-1R antagonists, such as Fosaprepitant, could be a new, promising therapeutic tool to inhibit CNV after this has been established.

In Vivo Photoacoustic Imaging of Anterior Ocular Vasculature: A Random Sample Consensus Approach

Visualizing ocular vasculature is important in clinical ophthalmology because ocular circulation abnormalities are early signs of ocular diseases. Photoacoustic microscopy (PAM) images the ocular vasculature without using exogenous contrast agents, avoiding associated side effects. Moreover, 3D PAM images can be useful in understanding vessel-related eye disease. However, the complex structure of the multi-layered vessels still present challenges in evaluating ocular vasculature. In this study, we demonstrate a new method to evaluate blood circulation in the eye by combining in vivo PAM imaging and an ocular surface estimation method based on a machine learning algorithm: a random sample consensus algorithm. By using the developed estimation method, we were able to visualize the PA ocular vascular image intuitively and demonstrate layer-by-layer analysis of injured ocular vasculature. We believe that our method can provide more accurate evaluations of the eye circulation in ophthalmic applications.

Update on the Management of High-Risk Penetrating Keratoplasty

PURPOSE OF REVIEW

In this article, we review the indications and latest management of high-risk penetrating keratoplasty.

RECENT FINDINGS

Despite the immune-privilege status of the cornea, immune-mediated graft rejection still remains the leading cause of corneal graft failure. This is particularly a problem in the high-risk graft recipients, namely patients with previous graft failure due to rejection and those with inflamed and vascularized corneal beds. A number of strategies including both local and systemic immunosuppression are currently used to increase the success rate of high-risk corneal grafts. Moreover, in cases of limbal stem cell deficiency, limbal stem cells transplantation is employed.

SUMMARY

Corticosteroids are still the top medication for prevention and treatment in cases of corneal graft rejection. Single and combined administration of immunosuppressive agents e.g. tacrolimus, cyclosporine and mycophenolate are promising adjunctive therapies for prolonging graft survival. In the future, cellular and molecular therapies should allow us to achieve immunologic tolerance even in high-risk grafts.

Angiogenesis Model of Cornea to Understand the Role of Sphingosine 1-Phosphate

The role of sphingolipids, mainly sphingosine 1-phosphate (S1P) and the receptors for which it serves as a ligand, is an interesting and promising area in both sphingolipid and vascular biology. S1P is crucial for establishing blood flow competent blood vessels (Jung et al. Dev Cell 23(3):600-610, 2012). The role of S1P in neovascular pathology is of great interest and promising as a target for treatment. Here we describe an easy and affordable in vivo model of neovascularization by an alkali chemical burn to the cornea. This gives a consistent and easy way to quantitate methods for neovascularization.

NADPH oxidase 2 plays a role in experimental corneal neovascularization

Corneal neovascularization, the growth of new blood vessels in the cornea, is a leading cause of vision impairment after corneal injury. Neovascularization typically occurs in response to corneal injury such as that caused by infection, physical trauma, chemical burns or in the setting of corneal transplant rejection. The NADPH oxidase enzyme complex is involved in cell signalling for wound-healing angiogenesis, but its role in corneal neovascularization has not been studied. We have now analysed the role of the Nox2 isoform of NADPH oxidase in corneal neovascularization in mice following chemical injury. C57BL/6 mice aged 8-14 weeks were cauterized with an applicator coated with 75% silver nitrate and 25% potassium nitrate for 8 s. Neovascularization extending radially from limbal vessels was observed in corneal whole-mounts from cauterized wild type mice and CD31+ vessels were identified in cauterized corneal sections at day 7. In contrast, in Nox2 knockout (Nox2 KO) mice vascular endothelial growth factor-A (Vegf-A), Flt1 mRNA expression, and the extent of corneal neovascularization were all markedly reduced compared with their wild type controls. The accumulation of Iba-1+ microglia and macrophages in the cornea was significantly less in Nox2 KO than in wild type mice. In conclusion, we have demonstrated that Nox2 is implicated in the inflammatory and neovascular response to corneal chemical injury in mice and clearly VEGF is a mediator of this effect. This work raises the possibility that therapies targeting Nox2 may have potential for suppressing corneal neovascularization and inflammation in humans.

Clinical Findings, Follow-up and Treatment Results in Patients with Ocular Rosacea

Objectives:

To report the clinical features, treatment options and complications in patients with ocular rosacea.

Materials and Methods:

The records of 48 eyes of 24 patients with ocular rosacea were retrospectively reviewed. Patients’ ocular signs and symptoms were scored between 1 and 4 points according to disease severity; tear film break-up time (BUT) and Schirmer’s test results were recorded before and after the treatment. Preservative-free artificial tears, topical antibiotic eye drops/ointments, short-term topical corticosteroids, topical 0.05% cyclosporine and oral doxycycline treatment were applied as a standard therapy to all patients. Additional treatments were given as needed. Complications were recorded.

Results:

Twenty-four patients with a mean age of 48.5±35.4 (32-54) years were followed for a mean 15±9.4 (8-36) months. Ocular findings included meibomitis in 100% of cases, anterior blepharitis in 83% (40 eyes), punctate keratopathy in 67% (32 eyes), chalazia in 50% (24 eyes), corneal neovascularization in 50% (24 eyes) and subepithelial infiltrates in 16.6% (8 eyes). Significant improvement of symptoms and clinical findings were achieved in all patients with treatment. The increases in Schirmer’s test and BUT were 3.3±1.5 and 4.5±2.8, respectively (p<0.05). Descemetocele and small corneal perforation occurred in 2 eyes; re-epithelialization was achieved in both eyes with tissue adhesive application (1 eye) and additional amniotic membrane transplantation (1 eye). Four eyes of three patients showed significant regression of corneal neovascularization with topical bevacizumab therapy.

Conclusion:

Ocular rosacea may present with a variety of ophthalmic signs. It is possible to control the ophthalmic disease with appropriate therapeutic modalities including topical corticosteroids, topical cyclosporine and systemic doxycycline.

Albuminated PLGA nanoparticles containing bevacizumab intended for ocular neovascularization treatment

Bevacizumab, an anti-VEGF antibody, has demonstrated trustworthy effects in treatment of retinal and choroidal neovascularization that both are crucial sight threatening conditions. However, the weak point is the short half-life of the drug in vitreous which necessitates frequent intravitreal injections. Accordingly employing controlled-release drug delivery systems such as polymeric nanoparticles (NPs) has been suggested. In this study albuminated-PLGA-NPs containing bevacizumab were prepared and studied intended for reducing the number of injections. NPs were formulated by double-emulsion method and a single dose of NPs was intravitreally injected to rabbits. The drug concentrations in vitreous and aqueous humor were assayed in different time intervals using ELISA and intraocular pharmacokinetic parameters were calculated. Moreover, coumarin-6 loaded albuminated-PLGA-NPs were employed to evaluate the distribution and persistence of the NPs in the posterior segment. Results revealed that the bevacizumab vitreous concentration maintained above 500 ng mL(-1) for about 8 weeks and 3.3 times elevation was observed in the drug vitreous MRT compared with the control. According to coumarin-6 NP tests, fluorescence emissions in posterior tissues were observed for 56 days which confirmed the nanoparticles persistence in ocular tissues during the test span. Therefore our prepared formulation may offer improvements in treatment of eye posterior segment neovascularization.

Resveratrol suppresses vascular endothelial growth factor secretion via inhibition of CXC-chemokine receptor 4 expression in ARPE-19 cells

The present study characterizes the effects of resveratrol (Res) on vascular endothelial growth factor (VEGF) secretion in retinal pigment epithelial (RPE) cells. ARPE-19 cells were treated with CoCl2, a hypoxia mimetic agent. CoCl2 treatment increased protein levels of hypoxia inducible factor-1α (HIF-1α) and CXC-chemokine receptor 4 (CXCR4), and secretion of VEGF. To confirm the effects of Res on VEGF secretion, the human umbilical vein endothelial cell tube formation assay was performed with conditioned medium from Res-treated ARPE-19 cells. The well-known antioxidant Res effectively blocked these effects and reduced phosphorylation of nuclear factor (NF)-κB, an upstream activator of CXCR4. Furthermore, Res also suppressed VEGF secretion induced by SDF-1, a ligand of CXCR4. Conditioned medium from Res-treated ARPE-19 cells clearly suppressed tube formation compared with hypoxia-treated conditioned medium. The results demonstrated that Res inhibited the hypoxia mimetic CoCl2-induced expression of VEGF in ARPE-19 cells. Res suppressed CXCR4 expression through decreased phosphorylation of NF-κB, resulting in downregulation of VEGF secretion.

Antilymphangiogenic therapy to promote transplant survival and to reduce cancer metastasis: what can we learn from the eye?

The lymphatic vasculature is - amongst other tasks - essentially involved in inflammation, (auto)immunity, graft rejection and cancer metastasis. The eye is mainly devoid of lymphatic vessels except for its adnexa, the conjunctiva and the limbus. However, several pathologic conditions can result in the secondary ingrowth of lymphatic vessels into physiologically alymphatic parts of the eye such as the cornea or the inner eye. Therefore, the cornea has served as an excellent in vivo model system to study lymphangiogenesis, and findings from such studies have substantially contributed to the understanding of central principles of lymphangiogenesis also with relevance outside the eye. Grafting experiments at the cornea have been extensively used to analyze the role of lymphangiogenesis in transplant immunology. In this regard, we recently demonstrated the crucial role of lymphatic vessels in mediating corneal allograft rejection and could show that antilymphangiogenic therapy increases graft survival. In the field of cancer research, we recently detected tumor-associated lymphangiogenesis in the most common malignant tumors of the eye, such as conjunctival carcinoma and melanoma, and ciliochoroidal melanoma with extraocular extension. These neolymphatics correlate with an increased risk of local recurrence, metastasis and tumor related death, and may offer potential therapeutic targets for the treatment of these tumors. This review will focus on corneal and tumor-associated ocular lymphangiogenesis. First, we will describe common experimentally used corneal lymphangiogenesis models and will recapitulate recent findings regarding the involvement of lymphatic vessels in corneal diseases and transplant immunology. The second part of this article will summarize findings about the participation of tumor-associated lymphangiogenesis in ocular malignancies and their implications for the development of future therapeutic strategies.

Three-year corneal graft survival rate in high-risk cases treated with subconjunctival and topical bevacizumab

PURPOSE

To evaluate the effect of combined subconjunctival and topical bevacizumab treatment on corneal graft survival rate in high-risk eyes.

METHODS

Prospective, consecutive, interventional case series. Fifty eyes of 50 high-risk patients scheduled for penetrating keratoplasty (PK) were included in the study; two Stevens-Johnson syndromes (SJS), five corneal combustions due to chemical burn, seven post-traumatic vascularised leucomas, 11 post-infectious vascularised leucomas, 19 rejected grafts and six corneal ulcers. Additional surgeries such as autologous limbal stem cell and/or amniotic membrane transplantation were performed together with PK in ten cases. All eyes received subconjunctival injection of 0.5 ml bevacizumab (25 mg/ml) after PK. Eyes with more than two quadrants of neovascularisation (NV) received bevacizumab drops (25 mg/ml) postoperatively for up to 12 weeks. Donor grafts were followed up for best-corrected visual acuity, graft clarity, change in NV, endothelial cell density loss (ECD), and adverse events. Mean follow-up was 36.5 months (range 32-61).

RESULTS

Best-corrected visual acuity increase was statistically significant in 82 % (41/50) of eyes 3 years after PK (paired t-test, p = 0.02). Thirty-five (70 %) high-risk grafts remained clear throughout the 3-year follow-up period. Decrease of corneal NV was observed in 84 % (42/50) of eyes treated with bevacizumab. ECD changed from preoperative 2,864 ± 301 down to 1,905 ± 187 cells/mm(2) at 3 postoperative years. A non-healing epithelial defect was recorded in one patient with SJS after 12 weeks of topical bevacizumab.

CONCLUSION

Combined subconjunctival and topical bevacizumab treatment may improve corneal graft survival rate in the majority of high-risk cases.

Early effects of dexamethasone and anti-VEGF therapy in an inflammatory corneal neovascularization model

Inflammatory angiogenesis is the pathogenic mechanism of various sight-threatening eye diseases, among them corneal neovascularization. Current treatment options include steroids which have undesirable side effects, or anti-VEGF which has only limited efficacy. In an inflammatory environment, however, angiogenesis can be stimulated by numerous factors not directly targeted by anti-VEGF therapy. The aim of this study was to induce corneal inflammation leading to angiogenesis, and investigate the early, differential effects of steroid and anti-VEGF therapy at the cellular, tissue, and gene expression levels. Fifty-two Wistar rats received a single intrastromal corneal suture to induce a controlled inflammatory angiogenic response. Rats were subsequently treated with dexamethasone, rat specific anti-VEGF, or goat IgG (control), topically 4 times daily for 7 days. In vivo confocal microscopy of the cornea was performed longitudinally from 5 h up to 7 d to investigate morphology at the cellular and tissue-level. In vivo photographic vessel analysis and immunohistochemistry were also performed. RT-PCR for VEGF-A, FGF-2, IL-6, TNF-α, CXCL2, CCL2, CCL3 and DLL4 was performed at 24 h, and for VEGF-A, IL-6, TNF-α, FGF-2, CXCL2, CCL2, and CCL3 at 7 days. Early infiltration of CD11b + myeloid cells into the cornea at 5 h post-suture was delayed by both treatments relative to controls; however neither treatment was able to suppress accumulation of myeloid cells at day 2 or 7. Limbal vessel dilation was inhibited at 5 h by both treatments, but only dexamethasone showed sustained effect until day 2. Early macrophage recruitment was also suppressed by dexamethasone (but not by anti-VEGF) until day 2. Dexamethasone furthermore suppressed corneal neovascularization at day 7 by over 90%, whereas suppression by anti-VEGF was 14%. Despite differential suppression of vessel dilation, macrophage recruitment, and vascular invasion, anti-VEGF and dexamethasone both down-regulated VEGF-A and IL-6 expression at 24 h with sustained effect to 7 d. They also both down regulated FGF-2 and TNF-α at 24 h and CCL2 at 7 d. In conclusion, anti-angiogenic treatments influence early, pre-angiogenic tissue activity such as limbal vessel dilation, inflammatory cell infiltration of the stroma, and macrophage recruitment. Importantly, the differential effects of steroids and anti-VEGF treatment in suppressing neovascular growth could not be attributed to differential inhibition of several major angiogenic and inflammatory factors in the early pre-sprouting phase, including IL-6, VEGF-A, FGF-2, TNF-α, CCL2, CCL3, CXCL2, or DLL4.

Treatment of Corneal Neovascularization Using Anti-VEGF Bevacizumab

Purpose. To evaluate antiangiogenic effect of local use of bevacizumab (anti-VEGF antibody) in patients with corneal neovascularization. Methods. Patients were divided into two groups. All patients suffered from some form of corneal neovascularization (NV). Patients in group A received 0.2–0.5 mL of bevacizumab solution subconjunctivally (concentration 25 mg/mL) in a single dose. Group A included 28 eyes from 27. Patients in group B applied bevacizumab eye drops twice daily (concentration 2.5 mg/mL) for two weeks. Group B included 38 eyes from 35 patients. We evaluated the number of corneal segments affected by NV, CDVA, and the incidence of complications and subjective complaints related to the treatment. The minimum follow-up period was six months. Results. By the 6-month follow-up, in group A the percentage reduction of the affected peripheral segments was 21.6% and of the central segments was 9.6%; in group B the percentage reduction of the central segments was 22.7% and of the central segments was 38.04%. In both groups we noticed a statistically significant reduction in the extent of NV. Conclusion. The use of bevacizumab seems to be an effective and safe method in the treatment of corneal neovascularization, either in the subconjunctival or topical application form.

Alkali burn versus suture-induced corneal neovascularization in C57BL/6 mice: an overview of two common animal models of corneal neovascularization

The purpose of the present study was to quantify and compare corneal hem- and lymphangiogenesis between alkali burn and suture-induced corneal neovascularization (CNV) in two commonly used mouse strains. A retrospective analysis was performed on C57BL/6 and FVB neovascularized corneas. CNV was induced by surface caustication with NaOH or intrastromal placement of three 10.0 nylon sutures. Hemangiogenesis and lymphangiogenesis extent was calculated on whole mounted corneas by CD31 and LYVE1 immunofluorescence analysis. Blood vessel growth was similar between alkali burn and suture-induced CNV in C57BL/6 mice, and between C57BL/6 and FVB sutured strains. On the contrary, corneal lymphangiogenesis was more pronounced in the C57BL/6 sutured mice versus the alkali burn group, and in the FVB strain versus both C57BL/6 models. These results indicate that significant differences occur in lymphangiogenesis, but not hemangiogenesis, in the alkali burn and suture-induced models in C57BL/6 mice. Furthermore, lymphangiogenesis is more pronounced in the albino (FVB) strain after suture placement. We suggest that the suture model has a number of advantages and may be preferentially used to study corneal lymphangiogenesis.

Correlations of vascular architecture and angiogenesis with pituitary adenoma histotype

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor in solid tumors. However, its role in angiogenesis in pituitary adenoma is controversial. Angiogenesis in solid tumors including pituitary adenoma is commonly evaluated by microvascular density (MVD). Here, we evaluated MVD and the role of VEGF in vascular architecture in 51 pituitary adenomas (24 nonfunctioning, 13 prolactin-secreting, 10 growth hormone-secreting, 3 adrenocorticotropic hormone-secreting, and 1 thyroid-stimulating hormone-secreting). Paraffin sections were stained with CD34 and VEGF. MVD and vascular architecture parameters (vessel area, diameter, perimeter, and roundness) were evaluated in CD34-stained sections. Immunohistochemistry showed 27/51 tumors (53%) were VEGF-positive. There were no significant differences in MVD, any vascular parameter, or adenoma volume between VEGF-positive and VEGF-negative tumors. VEGF mRNA expression was significantly higher in VEGF-positive tumors. There were no significant correlations between VEGF mRNA expression and MVD or vascular parameters. However, vessel diameter and perimeter were significantly larger in prolactin-secreting than nonfunctioning and growth hormone-secreting macroadenomas. The difference in vessel diameter was observed among both VEGF-positive and all adenomas (micro- and macroadenoma). Thus, VEGF may have limited roles in the development of vascular architecture and tumor angiogenesis in pituitary adenomas, but the differences in vessel architecture by histotype (i.e., larger vessel diameter and perimeter in prolactin-secreting adenomas) suggest the hormonal regulation of vessel architecture rather than angiogenesis.

One Year of Cornea Research in Review-2012

PURPOSE

The purpose of this study was to provide an update of significant cornea literature published in the past 1 year.

DESIGN

This was a literature review.

METHODS

The authors conducted a 1-year English-language literature search on PubMed, from January 1, 2012, to December 31, 2012, using the following terms: corneal transplantation, anterior lamellar keratoplasty, penetrating keratoplasty, endothelial keratoplasty, Descemet stripping automated endothelial keratoplasty, Descemet membrane endothelial keratoplasty, Descemet membrane endothelial transfer, ocular surface epithelial transplantation, limbal epithelial transplantation, cultivated oral mucosal epithelial transplantation, keratoprosthesis, infectious keratitis, cross-linking, keratoconus, corneal neovascularization, corneal imaging, optical coherence tomography, Pentacam Scheimpflug imaging, and in vivo confocal microscopy.

RESULTS

This review includes original articles and review articles that contain significant updates and novel aspects in the field of cornea from the following journals: American Journal of Ophthalmology, British Journal of Ophthalmology, Ophthalmology, Investigative Ophthalmology and Visual Science, and Cornea. Letters to the editor, unpublished work, manuscripts not in English, and abstracts were not included.

CONCLUSIONS

This review highlights significant literature that is applicable to the practicing ophthalmologist.

Bevacizumab (BVZ)-associated toxicities in children with recurrent central nervous system tumors treated with BVZ and irinotecan (CPT-11): a Pediatric Brain Tumor Consortium Study (PBTC-022)

BACKGROUND

The incidence and spectrum of acute toxicities related to the use of bevacizumab (BVZ)-containing regimens in children are largely unknown. This report describes the adverse events in a recently completed large phase 2 trial of BVZ plus irinotecan (CPT-11) in children with recurrent central nervous system tumors.

METHODS

Pediatric Brain Tumor Consortium trial-022 evaluated the efficacy and toxicity of BVZ (10 mg/kg administered intravenously) as a single agent for 2 doses given 2 weeks apart and then combined with CPT-11 every 2 weeks (1 course = 4 weeks) in children with recurrent central nervous system tumors. Children were treated until they experienced progressive disease, unacceptable toxicity or completed up to a maximum of 2 years of therapy. Toxicities were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. Patients who received at least 1 dose of BVZ were included for toxicity assessment.

RESULTS

Between October 2006 and June 2010, 92 patients evaluable for toxicity were enrolled and received 687 treatment courses. The most common toxicities attributable to BVZ included grade I-III hypertension (38% of patients), grade I-III fatigue (30%), grade I-II epistaxis (24%), and grade I-IV proteinuria (22%). Twenty-two patients (24%) stopped therapy due to toxicity.

CONCLUSIONS

The combination of BVZ and CPT-11 was fairly well-tolerated, and most severe BVZ-related toxicities were rare, self-limiting, and manageable.