A potential therapeutic strategy for inhibition of corneal neovascularization with new anti-VEGF agents

Extraction, physicochemical properties, bioactivities and application of natural sweeteners: A review

Natural sweeteners generally refer to a sweet chemical component directly extracted from nature or obtained through appropriate modifications, mainly secondary metabolites of plants. Compared to the first-generation sweeteners represented by sucrose and the second-generation sweeteners represented by sodium cyclamate, natural sweeteners usually have high sweetness, low-calorie content, good solubility, high stability, and rarely toxic side effects. Historically, researchers mainly focus on the function of natural sweeteners as substitutes for sugars in the food industry. This paper reviews the bioactivities of several typical natural sweeteners, including anti-cancer, anti-inflammatory, antioxidant, anti-bacterial, and anti-hyperglycemic activities. In addition, we have summarized the extraction, physicochemical properties, and application of natural sweeteners. The article aimed to comprehensively collate vital information about natural sweeteners and review the potentiality of tapping bioactive compounds from natural products. Hopefully, this review provides insights into the further development of natural sweeteners as therapeutic agents and functional foods.

Effect of Nintedanib Nanothermoreversible Hydrogel on Neovascularization in an Ocular Alkali Burn Rat Model

PURPOSE

To compare the therapeutic effects of different forms of nintedanib ophthalmic preparations on neovascularization corneal alkali burns in rats.

METHODS

Forty rat models of left eye corneal alkali burns were constructed, and the five groups (N = 8) were treated with normal saline, dexamethasone ointment (dexamethasone), 0.2% nintedanib aqueous solution and nintedanib nano thermoreversible hydrogel (NNTH). A slit lamp microscope was used to observe the area of neovascularization. The levels of the inflammatory factors were detected by ELISA. HE staining was performed on the rat corneas. Vascular endothelial growth factor (VEGFA) was detected by immunohistochemistry, and the expression of corneal VEGFA and CD31 was detected by western blotting. An MTT assay was performed to detect the cytotoxicity of nintedanib on human corneal epithelial cells (HCECs) and human umbilical vein vascular endothelial cells (HUVECs). Cell migration was detected by a cell scratch assay, and the proportion of apoptotic cells was detected by Annexin/PI double staining. Immunofluorescence and western blotting were performed to detect the protein expression of VEGFA and CD31.

RESULTS

NNTH had a stronger inhibitory effect on corneal neovascularization (CNV) in alkali-burned rats while reducing the level of inflammatory factors. NNTH had a longer drug duration of release than nanoformulations in vitro. Nintedanib at low concentrations (<8 μM) had no significant cytotoxicity to HCECs but significantly induced apoptosis and inhibited the expression of VEGFA and CD31 and the migration of HUVECs.

CONCLUSIONS

Nanomorphic thermoreversible hydrogel is superior among the nintedanib ophthalmic preparations, showing better inhibition of CNV in alkali-burned eyeballs and it blocked the migration and proangiogenic ability of HUVECs.

An injectable thermosensitive hydrogel for dual delivery of diclofenac and Avastin® to effectively suppress inflammatory corneal neovascularization

Corneal neovascularization (CNV) is a sequela of anterior segment inflammation, which could lead to vision impairment and even blindness. In the present study, the dual delivery of anti-inflammatory agent (i.e., diclofenac; DIC) and anti-VEGF antibody (i.e., Avastin®; Ava) by the thermosensitive hydrogel (Poly(dl-lactide)-poly(ethylene glycol)-poly(dl-lactide); PDLLA-PEG-PDLLA) is expected to effectively inhibit CNV via their synergistic effects. The optimal DIC micelles were formulated and then mixed with Ava and PDLLA-PEG-PDLLA aqueous solution to generate various DIC@Ava-loaded hydrogels. The co-encapsulation of DIC micelles and Ava did not influence the gelling behavior of the system, and the resulting DIC@Ava-loaded hydrogel provided sustained drug release of both DIC and Ava without compromising their pharmacological activity over 19 days. As indicated by in vitro cytotoxicity and in vivo ocular biocompatibility test, the proposed PDLLA-PEG-PDLLA hydrogel caused minimal cytotoxicity against all tested cell lines at a polymeric concentration ranging from 0.05 mg/mL to 0.8 mg/mL and demonstrated good ocular biocompatibility after a single subconjunctival injection. Using the rabbit CNV model, we documented the superior anti-angiogenic effects of the DIC@Ava-loaded hydrogel over Ava alone medication (treatment with Ava solution and Ava-loaded hydrogel) due to synergistic effects of anti-VEGF and anti-inflammatory action. Overall, the proposed DIC@Ava-loaded hydrogel might be a powerful strategy to reduce CNV.

Phytochemistry, pharmacological activity, and potential health benefits of Gly cyrrhiza glabra

Nature has always been an excellent source for many therapeutic compounds providing us with many medicinal plants and microorganisms producing beneficial chemicals. Therefore, the demand for medicinal plants, cosmetics, and health products is always on the rise. One such plant from the Leguminosae family is licorice and the scientific name is Glycyrrhiza glabra Linn. It is an herb-type plant with medicinal value. In the following article, we shall elaborately look at the plants' phytochemical constituents and the pharmacological impact of those substances. Several compounds such as glycyrrhizin, glycyrrhizinic acid, isoliquiritin, and glycyrrhizic acid have been found in this plant, which can provide pharmacological benefit to us with its anti-cancer, anti-atherogenic, anti-diabetic, anti-asthmatic, anti-inflammatory, anti-microbial, and antispasmodic activity. Alongside, these products have a different role in hepatoprotective, immunologic, memory-enhancing activity. They can stimulate hair growth, control obesity, and have anti-depressants, sedatives, and anticoagulant activity. This review examines recent studies on the phytochemical and pharmacological data and describes some side effects and toxicity of licorice and its bioactive components.

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.

Inhibitory Effects of Glycyrrhiza glabra and Its Major Constituent Glycyrrhizin on Inflammation-Associated Corneal Neovascularization

Glycyrrhiza glabra L. (Leguminosae) is widely used in folk medicines. Glycyrrhizin, an active compound of G. glabra, possesses anti-inflammatory activity. This study investigates the G. glabra methanol extract and glycyrrhizin for the treatment of corneal neovascularization (CNV). G. glabra was extracted in 70% aqueous methanol. Phytochemical tests, thin layer chromatography (TLC), and high performance liquid chromatography (HPLC) were used for the analysis of chemical composition. The topical solution of G. glabra methanol extract (2% w/v) and glycyrrhizin (1% w/v) was prepared in normal saline. After corneal burn (1 N NaOH), animals were left untreated for a week so that neovascularization appears in all groups. Treatments started on day 7 and continued for next 21 consecutive days. The animals were treated with 3 drops of various topical solutions thrice a day. Digital photograph analysis and histological studies were used for the evaluation of CNV. Phytochemical analysis of the G. glabra methanol extract showed the presence of saponins, phenols, carbohydrates, flavonoids, and proteins. TLC and HPLC confirmed the presence of glycyrrhizin. Photograph analysis of the extract and glycyrrhizin treated group showed a considerable decrease in CNV. Histological study of G. glabra and glycyrrhizin treated groups showed no blood vessels with properly arranged collagen fibers. This study showed that G. glabra and glycyrrhizin can be used for the treatment of CNV. Bioassay guided isolation can lead to preparation of ophthalmic solutions for the treatment of CNV.

Blockade of MMP-2 and MMP-9 inhibits corneal lymphangiogenesis

PURPOSE

To investigate the roles of a selective MMP-2 and -9 inhibitor (SB-3CT) in corneal inflammatory lymphangiogenesis.

METHODS

The expression of MMP-2 and -9 in the cornea after suture inplacement, treated with SB-3CT or negative control, was detected by real-time polymerase chain reaction (PCR). Inflammatory corneal neovascularization (NV) was induced by corneal suture placement. Mice were treated with SB-3CT eye drops (twice daily for 1 week, 5 μL per drop; 50, 100, or 200 μM). The outgrowth of blood and lymphatic vessels, and macrophage recruitment were analyzed by immunofluorescence assay. The expressions of vascular endothelial growth factor-C (VEGF-C) and its receptor VEGFR-3 were tested by real-time PCR.

RESULTS

MMP-2 and -9 expression were suppressed significantly by treatment with SB-3CT. The data demonstrated, for the first time, that SB-3CT strongly reduced corneal lymphangiogenesis and macrophage infiltration during inflammation. Furthermore, expressions of VEGF-C and its receptor VEGFR-3 were significantly inhibited by SB-3CT during corneal lymphangiogenesis.

CONCLUSIONS

These novel findings indicated that blockade of MMP-2 and -9 could inhibit lymphangiogenesis. Further investigation of this factor may provide novel therapies for transplant rejection and other lymphatic disorders.

Topical versus subconjunctival anti-vascular endothelial growth factor therapy (Bevacizumab, Ranibizumab and Aflibercept) for treatment of corneal neovascularization

In order to evaluate the effect of topical and subconjunctival anti-vascular endothelial growth factor (anti-VEGF) therapy, Ranibizumab, Bevacizumab and Aflibercept as a therapy for corneal neovascularization (NV) treatment, the aim of this study was to review all data related to some of anti-VEGF as a promising therapies for corneal NV treatment. Corneal NV is a dangerous condition leading to a marked reduction in vision due to angiogenesis of abnormal vessels that block light. During the recent years, we have recognized new drug proliferation for corneal NV treatment. Recently, anti-VEGF therapies are one of the most important drugs used for corneal NV treatment. Several growth factors are involved in angiogenesis. The most important growth factor in corneal angiogenesis is VEGF. VEGF can be considered as key mediators in corneal angiogenesis. It is upregulated during corneal NV. In fact, anti-VEGF therapies have shown efficacy in attenuation of corneal NV in both animal models and clinical trials. A promising therapeutic success has been achieved using antibodies directed against VEGF. Bevacizumab has demonstrated efficacy and efficiency in the treatment of different neo-vascular ocular diseases and it has partially reduced corneal NV through different routes of administrations: topical, subconjunctival, and intraocular application. A similar efficacy to bevacizumab profiles in the treatment of neo-vascular age-related macular degeneration was induced by ranibizumab. Moreover, at worse levels of initial visual acuity of diabetic macular edema, aflibercept was more effective at improving vision. Anti-VEGF agents (Bevacizumab, Ranibizumab and Aflibercept) seem to have a higher efficiency and efficacy for corneal NV treatment. Both subconjunctival therapy and topical therapy of bevacizumab prohibit corneal NV, while early treatment with subconjunctival administration of ranibizumab may successfully reduce corneal NV. Therefore, establishment of safe doses is highly important before these drugs can be involved in the clinical setting. Further investigations and studies are highly warranted to adjust the dose and route of administration for the antibodies directed against VEGF to be the key therapeutic agents in the corneal NV treatment.

Matrix metalloproteinase 14 participates in corneal lymphangiogenesis through the VEGF-C/VEGFR-3 signaling pathway

The aim of the present study was to investigate the roles of matrix metalloproteinase 14 (MMP-14) in corneal inflammatory lymphangiogenesis. The expression of MMP-14 in vivo was detected by immunohistochemistry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot assays, under various corneal conditions. pCMV-MMP-14 or empty pCMV vectors were injected into mouse corneal stroma, 3 days after suture placement in a standard suture-induced inflammatory corneal neovascularization assay. The outgrowth of blood and lymphatic vessels and macrophage recruitment were analyzed using immunofluorescence. The expression levels of vascular endothelial growth factor (VEGF) subtypes were tested by RT-qPCR. MMP-14 expression was upregulated significantly following various corneal injuries. The results demonstrated, for the first time, that MMP-14 strongly promotes corneal lymphangiogenesis and macrophage infiltration during inflammation. Furthermore, expression levels of VEGF-C and VEGF receptor-3, but not other VEGF components, were significantly upregulated by the intrastromal delivery of MMP-14 during corneal lymphangiogenesis. In conclusion, this study indicates that MMP-14 is critically involved in the processes of lymphangiogenesis. Inhibition of MMP-14 may provide a viable treatment for transplant rejection and other lymphatic disorders.

Role of Frequency Doubled Nd: Yag Laser in Treatment of Corneal Neovascularisation

INTRODUCTION

Cornea is the outermost transparent coat of eye along with sclera, for which its avascularity is essential for maintaining its transparency to have normal visual acuity. Corneal neovascularization is characterized by the invasion of new blood vessels into the cornea from the limbus interfering with corneal transparency, resulting in reduction in visual acuity. It also increases the risk of graft rejection. So their being a dire need to treat corneal neovascularisation, with laser photocoagulation being an effective means of treating it.

AIM

To evaluate the efficacy and safety of frequency doubled Nd:Yag laser photocoagulation in treatment of corneal neovascularisation.

MATERIALS AND METHODS

A single centre prospective study was carried out on patients attending the outpatient department of ophthalmology in Maharani Laxmi Bai Medical College, Jhansi. Forty eyes of 40 patients having corneal neovascularisation with quiescent eyes satisfying the inclusion criteria were selected and treated with laser. The efficacy of the procedure was noted in terms of area of corneal neovascularisation, status of treated vessels, area of corneal opacity, visual acuity. The above parameters of selected patients were recorded before treatment and subsequent follow up visits at 1 week, 1 month, 2 month and 3 month after laser. Paired t-test was used to calculate the p-value.

RESULTS

There was a statistically significant difference in the percentage mean area of corneal neovascularisation with a pre laser value of 31.93% to 17.62% after 3 months of laser treatment (p-value<0.0001). The percentage mean area of corneal opacity decreased from 30.75% to 23.74% (p<0.0001). Out of 185 corneal vessels, 99 (53.51%) vessels were completely occluded,17(9.18%) vessels were partially occluded and 69(37.29%) vessels were recanalised at the end of 3 months after laser treatment.

CONCLUSION

Frequency doubled Nd:Yag laser is an effective and safe method for the treatment of corneal neovascularisation.

The effects of PEP-1-FK506BP on dry eye disease in a rat model

As FK506 binding proteins (FK506BPs) are known to play an important role in the regulation of a variety of biological processes related to cell survival, this study was designed to examined the protective effects of FK506 binding protein 12 (FK506BP) on low humidity air flow induced dry eye in a rat model using transduced PEP-1-FK506BP. After the topical application of PEP-1-FK506BP, tear volumes were markedly increased and significant prevention of cornea damage was observed compared with dry eye rats. Further, immunohistochemical analysis demonstrated that PEP-1-FK506BP markedly prevented damage to the cornea, the bulbar conjunctiva, and the palpebral conjunctiva epithelial lining compared with dry eye rats. In addition, caspase-3 and PARP expression levels were found to be decreased. These results demonstrated that topical application of PEP-1-FK506BP significantly ameliorates dry eye injury in an animal model. Thus, we suggest that PEP-1-FK506BP can be developed as a new ophthalmic drop to treat dry eye diseases.

The effects of PEP-1-FK506BP on dry eye disease in a rat model

As FK506 binding proteins (FK506BPs) are known to play an important role in the regulation of a variety of biological processes related to cell survival, this study was designed to examined the protective effects of FK506 binding protein 12 (FK506BP) on low humidity air flow induced dry eye in a rat model using transduced PEP-1-FK506BP. After the topical application of PEP-1-FK506BP, tear volumes were markedly increased and significant prevention of cornea damage was observed compared with dry eye rats. Further, immunohistochemical analysis demonstrated that PEP-1-FK506BP markedly prevented damage to the cornea, the bulbar conjunctiva, and the palpebral conjunctiva epithelial lining compared with dry eye rats. In addition, caspase-3 and PARP expression levels were found to be decreased. These results demonstrated that topical application of PEP-1-FK506BP significantly ameliorates dry eye injury in an animal model. Thus, we suggest that PEP-1-FK506BP can be developed as a new ophthalmic drop to treat dry eye diseases.

Comparative study of ranibizumab and bevacizumab on corneal neovascularization in rabbits

PURPOSE

The aim was to compare the effect of subconjunctival injections of ranibizumab and bevacizumab on corneal neovascularization (NV) in rabbits.

METHODS

NV was induced by placing a suture at the corneal periphery of rabbits (n = 30 eyes). Immediately after suturing, the rabbits were divided into 3 groups and 7 days later administered subconjunctival injections of ranibizumab (Lucentis; 0.5 mg/0.05 mL), bevacizumab (Avastin; 5 mg/0.05 mL), or normal saline (control), respectively. The time-course photographs to measure the area of the corneal NV were obtained on days 7, 10, and 14 after suture placement. Histological examination and immunohistochemical analysis for the vascular endothelial growth factor and CD34 were performed.

RESULTS

Analysis of digital photographs showed that there was less corneal NV in the ranibizumab- and bevacizumab-treated eyes than in the control eyes (P = 0.012, 1-way analysis of variance); however, no significant differences between the ranibizumab- and bevacizumab-treated eyes were seen. In addition, there was less staining for vascular endothelial growth factor and CD34 in the corneas from the ranibizumab-treated eyes and bevacizumab-treated eyes than in the control eyes, and there were no significant differences in the staining intensity between the ranibizumab- and bevacizumab-treated eyes. Subconjunctival ranibizumab and bevacizumab injections were not associated with any complications during observations.

CONCLUSIONS

Subconjunctival administrations of ranibizumab or bevacizumab inhibit corneal NV in rabbits and have equivalent effects on it.

Serum vascular endothelial growth factor concentration in dogs diagnosed with chronic superficial keratitis

The objective of this study was to measure the vascular endothelial growth factor (VEGF) levels in dogs diagnosed with chronic superficial keratitis (CSK). The study was performed on 25 German shepherds (14 males and 11 females, aged between 3 and 11 years). The VEGF levels were determined in blood serum using commercially available enzyme-linked immunosorbent assay (ELISA; Quantikine Canine VEGF Immunoassay, R&D Systems). The test group of affected German shepherds was subdivided into two subgroups, based on the area of corneal neovascularisation. The first subgroup (9 patients) comprised dogs with neovascularisation observed in 1 to 2 quadrants of the right and left cornea, while the second subgroup (16 patients) comprised dogs with neovascularisation observed in 3 to 4 quadrants of the right and left cornea. The control group comprised 12 clinically healthy German shepherds (7 males and 5 females, aged between 3 and 9 years). The results were then statistically analysed by the Mann-Whitney test. The study indicated that the median serum VEGF concentration in healthy dogs was 14.9 pg/mL. The VEGF level observed in sick German shepherds was elevated (19.5 pg/mL) as compared to the values found in healthy dogs; however, a statistically significant increase in VEGF concentration, as compared to the values observed in healthy dogs, was only noted in the first subgroup, where the median VEGF concentration was 22.0 pg/mL. Elevated serum VEGF concentration was observed in German shepherds diagnosed with CSK. A statistically significant increase in VEGF levels was observed in dogs in the first stage of the disease, i.e. the early stage of neovascularisation.

Transduced PEP-1-FK506BP ameliorates corneal injury in Botulinum toxin A-induced dry eye mouse model

FK506 binding protein 12 (FK506BP) belongs to a family of immunophilins, and is involved in multiple biological processes. However, the function of FK506BP in corneal disease remains unclear. In this study, we examined the protective effects on dry eye disease in a Botulinum toxin A (BTX-A) induced mouse model, using a cell-permeable PEP-1-FK506BP protein. PEP-1-FK506BP efficiently transduced into human corneal epithelial cells in a time- and dose-dependent manner, and remained stable in the cells for 48 h. In addition, we demonstrated that topical application of PEP-1-FK506BP was transduced into mouse cornea and conjunctiva by immunohistochemistry. Furthermore, topical application of PEP-1-FK506BP to BTX-A-induced mouse model markedly inhibited expression levels of pro-inflammatory cytokines such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and macrophage inhibitory factor (MIF) in corneal and conjunctival epithelium. These results suggest PEP-1-FK506BP as a potential therapeutic agent for dry eye diseases. [BMB Reports 2013; 46(2): 124-129]

Corneal neovascularization: an anti-VEGF therapy review

Corneal neovascularization is a serious condition that can lead to a profound decline in vision. The abnormal vessels block light, cause corneal scarring, compromise visual acuity, and may lead to inflammation and edema. Corneal neovascularization occurs when the balance between angiogenic and antiangiogenic factors is tipped toward angiogenic molecules. Vascular endothelial growth factor (VEGF), one of the most important mediators of angiogenesis, is upregulated during neovascularization. In fact, anti-VEGF agents have efficacy in the treatment of neovascular age-related macular degeneration, diabetic retinopathy, macular edema, neovascular glaucoma, and other neovascular diseases. These same agents have great potential for the treatment of corneal neovascularization. We review some of the most promising anti-VEGF therapies, including bevacizumab, VEGF trap, siRNA, and tyrosine kinase inhibitors.

Anti-VEGF therapy with bevacizumab for anterior segment eye disease

PURPOSE

To review the current literature concerning the use of bevacizumab in treating neovascular disorders affecting the anterior segment ocular structures.

METHODS

The authors reviewed the literature on anti-vascular endothelial growth factor (VEGF) therapy with bevacizumab for various anterior segment neovascular disorders that was indexed in MEDLINE (up to January 2011).

RESULTS

Response to bevacizumab anti-VEGF therapy is variable, based on the amount of scarring, the chronicity and extent of corneal neovascularization, the disease process, and the medication formulation and its route of administration. Anti-VEGF agents are especially effective when administered early, before anatomical changes, such as corneal neovascularization and/or angle closure, are established. Neovascularization can recur if the ischemic or inflammatory process is not reversed, so eyes with long-standing diseases, such as autoimmune disorders that involve ongoing inflammation and VEGF production, seem to be less responsive to bevacizumab anti-VEGF therapy. For established neovascularization, combining anti-VEGF agents with the removal of established vessels may be more effective than anti-VEGF therapy alone. Subconjunctival bevacizumab may be more appropriate for focal, deep, and peripheral neovascularization, whereas diffuse superficial neovascularization with central corneal involvement may be best treated via topical application.

CONCLUSIONS

Besides the widely accepted use of bevacizumab in cancer therapy and chorioretinal neovascularization, the initial, striking, short-term response and patients' high tolerance of local bevacizumab therapy offer encouraging results for the potential role of anti-VEGF agents in treating anterior segment neovascular disorders. Controlled prospective trials are needed to establish the long-term safety, efficacy, and dosing guidelines for the use of anti-VEGF agents in anterior segment neovascularization.

Treatments for corneal neovascularization: a review

Corneal neovascularization (CNV) may be a physiological response to various stimuli, but a chronic and persistent upregulation of neoangiogenesis can result in pathological CNV. Pathological blood vessels are immature and lack structural integrity, predisposing the cornea to lipid exudation, inflammation, and scarring. CNV can therefore become a potentially blinding condition. In this review, we frame CNV in an epidemiological perspective, consider risk factors for CNV, provide an overview of CNV pathogenesis, and consider the impact of CNV on corneal transplantation. We consider treatments that are of largely historical interest, before reviewing contemporary medical and surgical treatments. Within medical treatments, we report on steroids, nonsteroidal anti-inflammatory agents, antivascular endothelial growth factor agents, and cyclosporine. Within surgical treatments, we report on the use of lasers, photodynamic therapy, superficial keratectomy, and diathermy/cautery-based treatments.

A potential therapeutic strategy for inhibition of ocular neovascularization with a new endogenous protein: rhEDI-8t

BACKGROUND

Endogenous angiogenesis inhibitors act as natural negative feedback in the focal area during the neovascularization process, and have less interference on physiological angiogenesis, and thus fewer negative side-effects. These inhibitors are potential candidates to combine with or substitutes for current popular anti-angiogenesis treatments to have synergistic effect. In this study, the effects of recombinant endothelial growth inhibitor protein (rhEDI-8t), a novel endogenous protein originated from collagen VIII, was investigated on ocular neovascularization (NV). Endostatin, a well-identified endogenous angiogenesis inhibitor, was compared in parallel and served as a positive control.

METHODS

The inhibitory effect of rhEDI-8t on vascular endothelial cells was evaluated by a human umbilical vascular endothelial cells (HUVEC) proliferation test and a bovine aortic endothelial cells (BAEC) migration experiment. The effect of rhEDI-8t on ocular NV was further investigated in mice with choroidal neovascularization (choroidal NV) induced by laser, ischemic retinopathy and transgenic mice with expression of VEGF in photoreceptors (rho/VEGF) respectively.

RESULTS

RhEDI-8t inhibited the growth of HUVECs and migration of BAECs stimulated by basic fibroblast growth factor (bFGF). Mice intravitreally treated with rhEDI-8t showed a significant reduction of choroidal NV, retinal NV and subretinal NV.

CONCLUSION

Endogenous angiogenesis inhibitor rhEDI-8t showed a potent anti-angiogenesis effect in both in vitro and in vivo experiments. It contributed to the suppression of ocular NV. The study suggested that rhEDI-8t could be a subsidiary potent therapeutic medicine in addition to anti-VEGF therapy in future clinical anti-angiogenesis treatment.

Galectin-3 protein modulates cell surface expression and activation of vascular endothelial growth factor receptor 2 in human endothelial cells

Angiogenesis is heavily influenced by VEGF-A and its family of receptors, particularly VEGF receptor 2 (VEGF-R2). Like most cell surface proteins, VEGF-R2 is glycosylated, although the function of VEGF-R2 with respect to its glycosylation pattern is poorly characterized. Galectin-3, a glycan binding protein, interacts with the EGF and TGFβ receptors, retaining them on the plasma membrane and altering their signal transduction. Because VEGF-R2 is glycosylated and both galectin-3 and VEGF-R2 are involved with angiogenesis, we hypothesized that galectin-3 binds VEGF-R2 and modulates its signal transduction as well. Employing a Western blot analysis approach, we found that galectin-3 induces phosphorylation of VEGF-R2 in endothelial cells. Knockdown of galectin-3 and Mgat5, an enzyme that synthesizes high-affinity glycan ligands of galectin-3, reduced VEGF-A mediated angiogenesis in vitro. A direct interaction on the plasma membrane was detected between galectin-3 and VEGF-R2, and this interaction was dependent on the expression of Mgat5. Using immunofluorescence and cell surface labeling, we found an increase in the level of internalized VEGF-R2 in both Mgat5 and galectin-3 knockdown cells, suggesting that galectin-3 retains the receptor on the plasma membrane. Finally, we observed reduced suture-induced neovascularization in the corneas of Gal3(-/-) and Mgat5(-/-) mice. These findings are consistent with the hypothesis that, like its role with the EGF and TGFβ receptors, galectin-3 contributes to the plasma membrane retention and proangiogenic function of VEGF-R2.

A case of ocular benign lymphoid hyperplasia treated with bevacizumab injection

We report the first case of ocular benign lymphoid hyperplasia (BLH) treated with subconjunctival injection of bevacizumab (Avastin). A 27-year-old man presented to our clinic with conjunctival masses and limbal neovascularization. An incisional biopsy yielded the diagnosis of BLH. The patient was subsequently given a subconjunctival injection of bevacizumab (1.25 mg / 0.1 mL). The patient did not experience recurrence or malignant metaplasia during the one-year follow-up period. In patients with conjunctival BLH, subconjunctival injection of bevacizumab can be a useful treatment option in patients unable to undergo a surgical procedure due to limbal neovascularization.

Bevacizumab accelerates corneal wound healing by inhibiting TGF-beta2 expression in alkali-burned mouse cornea

This study investigated the effect of subconjunctival injections of bevacizumab, an anti-VEGF antibody, on processes involved in corneal wound healing after alkali burn injury. Mice were divided into three groups: Group 1 was the saline-treated control, group 2 received subconjunctival injection of bevacizumab 1 hr after injury and group 3 received bevacizumab 1 hr and 4 days after injury. Cornea neovascularization and opacity were observed using a slit lamp microscope. Corneal repair was assessed through histological analysis and immunostaining for CD31, alpha-SMA, collagen I, and TGF-beta2 7 days post-injury. In group 3, injection of bevacizumab significantly lowered neovascularization and improved corneal transparency. Immunostaining analysis demonstrated a reduction in CD31, alpha-SMA and TGF-beta2 levels in stroma compared to group 1. These results indicate that bevacizumab may be useful in reducing neovascularization and improving corneal transparency following corneal alkali burn injury by accelerating regeneration of the basement membrane.

The effect of topical bevacizumab on corneal neovascularization

PURPOSE

To examine the effect of topical bevacizumab on corneal neovascularization (NV) over a period of 3 months.

DESIGN

Prospective, nonrandomized, masked observational case series.

PARTICIPANTS

Ten eyes of 7 patients with corneal NV.

METHODS

Patients received topical bevacizumab (1.25%) twice daily. Ophthalmic evaluations included visual acuity, slit-lamp examination, and tonometry.

MAIN OUTCOME MEASURES

Corneal NV and changes in ophthalmic evaluations.

RESULTS

Decreased corneal NV was noted in 7 of 10 eyes, usually within 1 month of treatment. Epitheliopathy (epithelial defect, epithelial erosion) was observed in 6 of 10 eyes, 1 resulting in corneal thinning. Adverse effects generally appeared during the second month of treatment.

CONCLUSIONS

Topical application of bevacizumab was effective in reducing corneal NV within the first month. However, by the second month there was an increased risk of adverse effects.

The effects of the subconjunctival injection of bevacizumab (Avastin®) on angiogenesis in the rat cornea

The purpose of this study was to evaluate the effects of the use of the subconjunctival injection of bevacizumab (Avastin®) on angiogenesis in the rat cornea. Corneas of 20 Wistar male rats were cauterized with silver nitrate crystal. Animals were divided in four groups: control group (GC) that received subconjunctivally 0.02 ml of 0.9% saline solution on the day of the lesion; group GO that received subconjunctivally 0.02 ml of bevacizumab just after the lesion; group G3 that received bevacizumab on day 3 and group G5 that received bevacizumab on day 5 after lesion. Animals were euthanized on day 7. The newly formed vessels were quantified after China Ink perfusion and photographs were obtained and analyzed in a computerized system (Image Pro-Plus®). In the control group, neovascularization covered 53.56% ± 15.11 (mean ± SD) of the corneal surface, compared with 35.57% ± 18.80 (mean ± SD) in the G0 group, 30.60%±11.82 (mean±SD) in the G3 and 35.86%±0.07 (mean±SD) in the G5. The results showed an inhibition of angiogenesis when the control group was compared with all treated groups. These results suggest that subconjunctival injection of bevacizumab is able to inhibit corneal angiogenesis independently of the day of treatment.

Bevacizumab (Avastin) as a potential novel adjunct in the management of pterygia

In the last two decades of angiogenesis research, a variety of angiogenic regulators have been identified. The discovery of several antiangiogenic factors has led to the development of novel ophthalmic therapies. Pterygia are characterized by the encroachment of a fleshy fibrovascular tissue from the bulbar conjunctiva onto the cornea. The pathogenesis of pterygia is presently uncertain and its treatment is quiet controversial. It has also been postulated that the development of pterygia depends on a changed angiogenic stimulator-to-inhibitor ratio. On of the most important known mediators of angiogenesis in pterygia is vascular endothelial growth factor (VEGF). In this article, we briefly review the evidences supporting involvement of vascular endothelial growth factor (VEGF) in the pathogenesis of pterygia and then based on these evidences, we hypothesize that local application of bevacizumab, a monoclonal antibody against VEGF, may inhibit neovascularization and thus, may stop the progression or prevent the recurrence of pterygia.