Reduce Corneal Neovascularization Research Articles

DZ2002 alleviates corneal angiogenesis and inflammation in rodent models of dry eye disease via regulating STAT3-PI3K-Akt-NF-κB pathway.

Dry eye disease (DED) is a prevalent ocular disorder with a multifactorial etiology. The pre-angiogenic and pre-inflammatory milieu of the ocular surface plays a critical role in its pathogenesis. DZ2002 is a reversible type III S-adenosyl-L-homocysteine hydrolase (SAHH) inhibitor, which has shown excellent anti-inflammatory and immunosuppressive activities in vivo and in vitro. In this study, we evaluated the therapeutic potential of DZ2002 in rodent models of DED. SCOP-induced dry eye models were established in female rats and mice, while BAC-induced dry eye model was established in female rats. DZ2002 was administered as eye drops (0.25%, 1%) four times daily (20 μL per eye) for 7 or 14 consecutive days. We showed that topical application of DZ2002 concentration-dependently reduced corneal neovascularization and corneal opacity, as well as alleviated conjunctival irritation in both DED models. Furthermore, we observed that DZ2002 treatment decreased the expression of genes associated with angiogenesis and the levels of inflammation in the cornea and conjunctiva. Moreover, DZ2002 treatment in the BAC-induced DED model abolished the activation of the STAT3-PI3K-Akt-NF-κB pathways in corneal tissues. We also found that DZ2002 significantly inhibited the proliferation, migration, and tube formation of human umbilical endothelial cells (HUVECs) while downregulating the activation of the STAT3-PI3K-Akt-NF-κB pathway. These results suggest that DZ2002 exerts a therapeutic effect on corneal angiogenesis in DED, potentially by preventing the upregulation of the STAT3-PI3K-Akt-NF-κB pathways. Collectively, DZ2002 is a promising candidate for ophthalmic therapy, particularly in treating DED.

Effect of medroxyprogesterone and doxycycline on vascular endothelial growth factor (VEGF) expression and corneal neovascularization in corneal alkali trauma

Ocular chemical trauma is a true emergency in ophthalmology. Chemical trauma on the ocular area may disturb vision, reduce the quality of life, and functional state. Prompt and adequate treatment is needed to prevent further complications, such as a decrease in vision due to corneal neovascularization. Treatment started with immediate eradication of the chemical agent by continuous rinsing and followed by inflammation and epithelial defect control. Medroxyprogesterone and doxycycline are two common treatments used in ocular chemical trauma. We speculate that both medications may influence VEGF expression and corneal neovascularization in corneal alkali trauma. It was demonstrated that medroxyprogesterone and doxycycline reduce the expression of VEGF, hence, reducing corneal neovascularization.

Topical Nanoemulsion of a Runt-related Transcription Factor 1 Inhibitor for the Treatment of Pathologic Ocular Angiogenesis.

Purpose:To test the efficacy of runt-related transcription factor 1 (RUNX1) inhibition with topical nanoemulsion containing Ro5-3335 (eNano-Ro5) in experimental ocular neovascularization.Design:Preclinical experimental study.Participants:In vitro primary culture human retinal endothelial cell (HREC) culture. C57BL/6J 6- to 10-week-old male and female mice.Methods:We evaluated the effect of eNano-Ro5 in cell proliferation, cell toxicity, and migration of HRECs. We used an alkali burn model of corneal neovascularization and a laser-induced model of choroidal neovascularization to test in vivo efficacy of eNano-Ro5 in pathologic angiogenesis in mice. We used mass spectrometry to measure penetration of Ro5-3335 released from the nanoemulsion in ocular tissues.Main Outcome Measures:Neovascular area.Results:RUNX1 inhibition reduced cell proliferation and migration in vitro. Mass spectrometry analysis revealed detectable levels of the active RUNX1 small-molecule inhibitor Ro5-3335 in the anterior and posterior segment of the mice eyes. Topical treatment with eNano-Ro5 significantly reduced corneal neovascularization and improved corneal wound healing after alkali burn. Choroidal neovascularization lesion size and leakage were significantly reduced after treatment with topical eNano-Ro5.Conclusions:Topical treatment with eNano-Ro5 is an effective and viable platform to deliver a small-molecule RUNX1 inhibitor. This route of administration offers advantages that could improve the management and outcomes of these sight-threatening conditions. Topical noninvasive delivery of RUNX1 inhibitor could be beneficial for many patients with pathologic ocular neovascularization.

Topical Vitamin C Promotes the Recovery of Corneal Alkali Burns in Mice.

Background Vitamin C (Vc) has been found to promote corneal wound healing after alkali burns. However, the specific mechanism and functional modes are still unclear. The present study sought to assess the mechanisms of Vc function on corneal alkali burns. Methods Eighty BALB/c mice were divided into four groups: a normal group without alkali injury (n = 10), an alkali injury group without any treatment (1-day group, n = 10), a Vc group treated with topical 10% Vc (Vc group, n = 30), and a control group treated with topical sterile water (control group, n = 30). Except in the blank control group, the alkali injuries were induced in one eye of each mouse. The mice in the treatment group were given Vc by topical application (q 1 h for 6 days), while those in the control group were given topical sterile water. The clinical evaluations, including corneal fluorescent staining, corneal opacity, and neovascularization, were assessed on days 1, 4, 7, and 10 using slit-lamp microscopy. Ten mice at each time point were sacrificed. The protein expressions in the corneas of p63, PCNA, CK3, MPO, CD31, and α-SMA were detected by immunohistochemistry to examine the corneal epithelial stem cells, corneal epithelium wound healing, corneal stroma inflammation, neovascularization, and fibrosis. Results The scores of the corneal epithelium defects, corneal neovascularization, and corneal opacities in the Vc group were significantly decreased compared to the control group on day 10. We found that Vc promoted the activation of the corneal epithelial stem cells as shown by a higher number of p63-positive and PCNA-positive cells and an increased CK3 expression when compared with the control group (p < 0.001). The central corneal re-epithelialization was completed by day 10. Moreover, Vc inhibited MPO, CD31, and α-SMA expressions. These results first indicated that the frequent use of topical Vc in the first 6 days of corneal alkali burns alleviated corneal inflammatory cell infiltration, activated corneal epithelial stem cell activity, and reduced corneal neovascularization and fibrosis within 10 days. Conclusions The study, therefore, showed the therapeutic benefits of Vc on corneal alkali burns and provided new insight into the mechanisms of Vc regulation on corneal wound healing.

Effects of Amniotic Membrane Transplantation in Ocular Burns: A Meta-Analysis

<i>Background: </i>Ocular burns is a serious eye injury with a high rate of blindness, efforts should be made to eliminate the serious complications, prevent from lifelong disability, and improve emergency interventions and treatment.<i> Objective: </i>To evaluate the effectiveness of amniotic membrane transplantation (AMT) in ocular burns. <i>Methods:</i> The following electronic databases were searched: PubMed, Web of Science, and Cochrane Library. With the keyword “amniotic membrane” and “ocular burn”. No limitation of year, language, gender, age, nationality, etc. Animal trials, patients with other ocular surface diseases, and amniotic membrane transplantation combined with other surgeries were excluded. We evaluated the corneal epithelium healing time (CEHT), tear break-up time (TBUT), Schirmer test (ST), corneal neovascularization, the formation of symblepharon, and lid abnormalities after conventional treatment (CT) and AMT. The differences were tested by referring to the Cochrane Handbook. Pooled estimates were determined with RevMan software, version 5.3. <i>Results:</i> 5 studies with 310 eyes of 282 participants suffering from ocular burns were included. There was no significant difference between CT and AMT among the following outcomes: CEHT, TBUT, ST, formation of symblepharon, and lid abnormalities, except the extent of corneal neovascularization, which was less in patients treated with AMT (RR 0.81; 95% CI 0.68, 0.96; I² = 40%, p = 0.02). <i>Conclusions:</i> Compared to CT, AMT does not show better advantages in promoting epithelial healing, improving tear film status, and preventing complications such as symblepharon formation and eyelid abnormalities except reducing corneal neovascularization.

Sensory neurons directly promote angiogenesis in response to inflammation via substance P signaling.

Blood vessels and nerves travel together to supply most tissues in the body. However, there is a knowledge gap in the mechanisms underlying the direct regulation of angiogenesis by nerves. In the current study, we examined the regulation of angiogenesis by sensory nerves in response to inflammation using the cornea, a normally avascular and densely innervated ocular tissue, as a model. We used desiccating stress as an inflammatory stimulus in vivo and found that sub-basal and epithelial nerve densities in the cornea were reduced in dry eye disease (DED). We established a co-culture system of trigeminal ganglion sensory neurons and vascular endothelial cells (VEC) and found that neurons isolated from mice with DED directly promoted VEC proliferation and tube formation compared with normal controls. In addition, these neurons expressed and secreted higher levels of substance P (SP), a proinflammatory neuropeptide. SP potently promoted VEC activation in vitro and blockade of SP signaling with spantide I, an antagonist of SP receptor Neurokinin-1, significantly reduced corneal neovascularization in vivo. Spantide I and siRNA knockdown of SP abolished the promotion of VEC activation by DED neurons in vitro. Taken together, our data suggested that sensory neurons directly promote angiogenesis via SP signaling in response to inflammation in the cornea.

Trehalose in ophthalmology.

Trehalose, a disaccharide of glucose, is a naturally occurring nontoxic and nonreducing bioactive sugar. Trehalose is synthetized by many organisms when cells are exposed to stressful conditions, including dehydration, heat, oxidation, hypoxia or even anoxia. Although trehalose is not synthesized by mammalian cells, it has recently been demonstrated to have a number of important properties that indicate its utility in humans. Trehalose enables wound healing by protecting cells, especially cell membranes, from oxidative injury and dessication. When the injured cornea is treated with trehalose, corneal inflammation, scar formation and corneal neovascularization are suppressed. In dry eye disease, trehalose decreased cell apoptosis and reduced oxidative, inflammatory and proteolytic activity at the ocular surface. In UVB irradiated cornea, trehalose suppressed photodamage evoked by UVB rays. It decreased the intracorneal inflammation and reduced corneal neovascularization. Trehalose prevented postoperative fibrous scar formation after ocular surgery, such as glaucoma filtration surgery. The non-toxicity of trehalose allows its administration in humans for extended periods and enables its use in various disease states.

The long-term effect of tacrolimus on alkali burn-induced corneal neovascularization and inflammation surpasses that of anti-vascular endothelial growth factor.

PurposeTo investigate the effect of tacrolimus in alkali burn-induced corneal neovascularization (NV) and inflammation and to compare with anti-vascular endothelial growth factor (anti-VEGF).MethodsAfter corneal alkali-burn, 84 Wistar rats were randomly divided into three groups and received either saline solution or 0.05% tacrolimus (0.5 mg/mL) four times daily, or subconjunctival anti-VEGF injection (0.5 mg/0.05 mL). Corneal NV, opacity and epithelial defects, the status of inflammation, and the levels of proinflammatory and angiogenic cytokines were assessed on Days 3, 7, 14 and 28 post-injury.ResultsCompared with the control, tacrolimus significantly reduced corneal NV on Days 7, 14 and 28 post-injury, and anti-VEGF significantly reduced corneal NV at each assessment. Nevertheless, the tacrolimus group had significantly less corneal NV than the anti-VEGF group on Days 14 and 28. Furthermore, both tacrolimus and anti-VEGF significantly decreased the VEGF-A expression on Days 7 and 14, with no significant difference between the two groups. Moreover, corneal inflammatory response was alleviated, and corneal opacity and epithelial defects were significantly reduced by tacrolimus. Additionally, the expression of IL-1β, IL-6, monocyte chemotactic protein-1, macrophage inflammatory protein-1α and TGF-β were significantly decreased by tacrolimus.ConclusionOur findings suggested that 0.05% tacrolimus suspension eye drops effectively reduced alkali burn-induced corneal NV and inflammation, with a better effect than subconjunctival anti-VEGF injections on Days 14 and 28.

Efficacy of fumagillin bicyclohexylamine on experimental corneal neovascularization in rat model.

Fumagillin has been previously used to treat corneal microsporidial keratitis and also identified as an angiogenesis inhibitor. This study aimed to evaluate efficacy of fumagillin bicyclohexylamine on the rat model of corneal neovascularization induced by silver nitrate cauterization. Twenty-four Albino Wistar rats (n = 24) were divided into three groups. Following silver nitrate-induced corneal injury, eyes in Group 1 received one drop of 5mg/mL topical fumagillin bicyclohexylamine four times daily for 10days. Group 2 received subconjunctival injection of 0.1mL fumagillin bicyclohexylamine (2.5mg/mL) on day 1 and day 5. Group 3 received artificial tears and lubricants four times daily for 10days as control. On day 10, animals were sacrificed. Corneal specimens were obtained and prepared to assess vascular endothelial growth factor (VEGF-C) levels and corneal angiogenic microvessel density. There was no significant difference in VEGF-C levels between the groups (P = 0.994). Assessment of angiogenic microvessel density for peripheral corneal zone also did not reveal significant difference between the groups (P = 0.113). However, mean vascular density in Group 1 and Group 2 was significantly higher for both midperipheral and central corneal zones in comparison with Group 3 (P = 0.003, P = 0.015). Previously proved to be effective for treatment of microsporidial keratitis in humans, topical and subconjunctival concentration or dosing of fumagillin bicyclohexylamine failed to reduce corneal neovascularization induced by silver nitrate in this study. Further studies comparing different concentrations and dosing may detect inhibitory effects of fumagillin on corneal neovascularization without inducing toxicity.

Comparison of different doses of subconjunctival sunitinib with bevacizumab in the treatment of corneal neovascularization in experimental rats.

Background:To compare the efficacy of subconjunctival administration of bevacizumab and different doses of sunitinib malate in reducing corneal neovascularization (CNV).Materials and Methods:In this experimental study, central corneal cauterization was created in the right eye of fifty male Sprague–Dawley rats. On day 1 (1 week after cauterization), rats were randomly assigned into five treatment groups. Group control (n = 10) received subconjunctival injection of 0.02 ml of base saline solution. Group 1 (n = 10) received 0.02 ml of bevacizumab (25 mg/ml). Group 2, 3, and 4 (n = 10 for each group) were treated with 0.02 ml of sunitinib malate (10, 20, and 50 μg/ml, respectively). On days 1, 7, and 14, digital photographs of the cornea were taken, and the area of CNV was measured.Results:During the 2-week follow-up, CNV area in treatment groups was less than in control group (P < 0.05). On day 7, corneal avascular area was highest in Group 3 at 63%. On day 14, the area of CNV in Groups 2 and 3 was less than in Group 1 (P = 0.031 and 0.011, respectively), but the difference between Groups 2 and 3 was not statistically significant (P = 0.552). The decreased CNV area on day 14 in Group 4 was significant in comparison to bevacizumab, but it was not significant on day 7 (P = 0.25 on day 7 and 0.002 on day 14).Conclusion:Subconjunctival sunitinib malate is more effective than bevacizumab in regressing CNV. This effect is more prominent on day 14.

Traitements comparés de la néovascularisation cornéenne : injections sous-conjonctivales de bévacizumab et/ou photothérapie dynamique

To evaluate and compare the efficacy of subconjunctival bevacizumab injections alone, photodynamic therapy alone and combined treatments for reduction of corneal neovascularization. This study was conducted as a prospective case series. A total of seven eyes of 7 patients with corneal neovascularization caused by ocular surface disorders including fungal infectious keratitis and penetrating keratoplasty were included in the study. Patients were randomized into the three following groups: patients in group A received a single subconjunctival injection of 10mg (0.4mL) of bevacizumab, patients in group B were treated with photodynamic therapy with verteporfin (6mg/m(2)) to the neovascularized area and those in group C received a subconjunctival injection of bevacizumab and photodynamic therapy 7 days later. Morphological changes in neovascularization were evaluated over 6 months using slit-lamp biomicroscopy and digital corneal photography. A computer-assisted semi-automatic analysis of the area of corneal neovascularization was performed with Image J software. Recession of corneal vessels was observed in all eyes at 1 month post-treatment. The neovascularized surface area in all groups combined showed a decrease in the first month after treatment and this decrease continued up to the 6th month. The surface area of corneal neovascularization decreased by 34.05±8.28% in group A (subconjunctival injection of bevacizumab), by 42.06±28.36% in group B (photodynamic therapy with verteporfin) and by 51.67±18.93% in group C (combined subconjunctival injection of bevacizumab and photodynamic therapy). A combined treatment consisting of a subconjunctival injection followed by a PDT session 7 days later might be more effective for the treatment of corneal neovascularisation. No serious local or systemic adverse events were observed. Our medium-term results suggest that combined subconjunctival injection of bevacizumab and photodynamic therapy with verteporfin might be used safely and effectively to reduce corneal neovascularization surface. This combined therapy may show a tendency toward greater efficacy than the individual monotherapies. Controlled prospective randomized multicentric trials with a larger sample size are necessary to assess long-term efficacy and to confirm these results.

Effects of Adoptive Transferring Different Sources of Myeloid-Derived Suppressor Cells in Mice Corneal Transplant Survival.

Adoptively transferring different sources of myeloid-derived suppressor cells (MDSCs) may assist in mice corneal transplant survival. Allogeneic full thickness corneal transplantation (donor C57BL/6 to recipient Balb/c mice) was performed. Naive myeloid cells, inflammation-induced MDSCs (iMDSCs), and tumor-induced MDSCs (tMDSCs) were purified from bone marrow of naive, cecal ligation and puncture, or tumor-bearing Balb/c mice, respectively. The inhibitory abilities of myeloid cells toward CD4(+) T cell proliferation were accessed by in vitro carboxyfluorescein diacetate, succinimidyl ester (CFSE) assays. Myeloid cells were adoptively transferred to corneal recipients by retroorbital injection after corneal transplantation. Corneal grafts were examined and photographed for a period of 45 days. The growth of corneal graft neovascularization was quantitatively measured by image editing software. Histopathology was performed to evaluate corneal graft inflammation. The iMDSCs and tMDSCs significantly inhibited T cell proliferation in vitro and significantly prolonged corneal allograft survival in vivo. Strikingly, iMDSC transferring significantly reduced neovascularization that was comparable to transferring of tMDSCs, without additional immunosuppression. However, additional adoptive transfer of MDSCs did not further ameliorate corneal survival in these allogeneic corneal transplantation mice. Inflammation-induced MDSC transfer could reduce corneal neovascularization and prolong corneal allograft survival.

Comparative Study of Tacrolimus and Bevacizumab on Corneal Neovascularization in Rabbits

PurposeTo compare the anti‐angiogenic effects of tacrolimus and bevacizumab on corneal neovascularization in rabbits.MethodsNeovascularization was induced in 32 eyes of 16 rabbits by placing suture in the corneal stroma. Seven days after suture placement, all rabbits were divided into four groups and were treated subconjunctivally with bevacizumab 0.05 mL (5 mg/0.05 mL; AVA_sub), Tacrolimus 0.05 mL (0.25 mg/0.05 mL; TAC_sub), balanced salt solution (0.05mL was subconjunctivally injected in one eye of each rabbit and applied by eye drops in the other eye, control group), and Tacrolimus eye drops (5 mg/5 mL applied four times daily; TAC_drop). Digital photographs were obtained and the surface area of corneal neovascularization was measured 7 days after subconjunctival injections. Corneal specimens were analyzed histopathologically and were used to measure the concentration of VEGF, TNF‐α, IFN‐γ, IL‐1β, and MCP‐1 mRNA by RT‐PCR.ResultsIn digital photographs, the neovascularized area was decreased in all treatment groups (AVA_sub 0.58, TAC_sub 0.60, TAC_drop 0.68) compared with the control group (BSS 0.81). The histological examination showed markedly regressed new vessels in treatment groups, and the immunohistochemical staining revealed weakly stained with anti‐VEGF and anti‐F4/80 antibodies in the treatment groups. In semi‐quantitative RT‐PCR, the concentration of VEGF (AVA _sub 0.24, TAC_drop 0.18), TNF‐α (AVA_sub 0.19, TAC_sub 0.24, TAC_drop 0.15), and IL‐1ß (AVA_sub 0.19, TAC_sub 0.33, TAC_drop 0.18) mRNA were significantly lower in the treatment groups than in the control group (VEGF 0.47, TNF‐α 0.44, IL‐1β 0.87) (P &lt; 0.05).ConclusionsTopical and subconjunctival tacrolimus application may be useful in reducing corneal neovascularization and have comparable effects to subconjunctival bevacizumab injection.

Rho‐associated kinase inhibition prevents pathological neovascularization after corneal trauma

AbstractPurpose The aim of this study was to investigate the effect of AMA0526, a selective and locally acting ROCK inhibitor on endothelial cells in vitro and in vivo by using a mouse corneal neovascularization (NV) model.Methods In vitro, the effect of AMA0526 (0.1; 1 and 10 µM) on endothelial cell proliferation and FBS‐stimulated migration was investigated. A mouse corneal micropocket (MCM) model was used to study the in vivo effect of the ROCK inhibitor on corneal NV. A bFGF pellet was implanted in both eyes and topical administration was applied once daily using AMA0526 (0.1%) in one eye and vehicle (PEG/H2O) in the contralateral eye. Outcome was investigated by analysing vessel length, clock hours and NV area 7 days post implantation. Histological outcome was evaluated by immunohistochemical staining for inflammation (CD45) and angiogenesis (CD31).Results HBMEC and HUVEC proliferation was significantly inhibited in a dose‐dependent manner by ROCK inhibition. AMA0526 (1 and 10 µM) also induced significant reduction of FBS‐stimulated endothelial cell migration, respectively by 29% and 40%. In the MCM model, AMA0526 treatment significantly reduced NV area by 28% and vessel length by 28%, as compared to vehicle treated. These effects were associated with a decreased infiltration of inflammatory cells (P&lt;0.05; 32% reduction) and a reduced blood vessel density (P&lt;0.05; 40% reduction) at day 7.Conclusion AMA0526 inhibits endothelial cell proliferation and migration in vitro and is efficacious in reducing corneal NV after bFGF micropocket implantation. These results indicate that ROCK inhibition by AMA0526 may have therapeutic value for the treatment of pathological corneal NV.

Results of a phase I/II clinical trial: standardized, non-xenogenic, cultivated limbal stem cell transplantation

BackgroundTo determine if a standardized, non-xenogenic, reduced manipulation cultivation and surgical transplantation of limbal stem cell grafts is a safe and effective treatment option for patients with total and partial limbal stem cell deficiency.MethodsIn vitro cellular outgrowth and phenotype of the limbal epithelial cell and composite grafts were validated using a new protocol. Patients received either autologous (n = 15) or allogenic (n = 3) explants cultured using a standardized protocol free from xenogenic products. The resulting grafts were transplanted using a reduced manipulation surgical technique.ResultsThe majority of cells (>50%) displayed a progenitor phenotype typified by positive immunofluorescence for ∆Np63, CK14 and ABCG2 and low immunofluorescence for CK3/12 and desmoglein 3 proteins. The surgical protocol was designed to minimize manipulation and the graft itself was secured without sutures. The transplant recipients were followed for a mean of 24 months. Twelve of the 18 transplant recipients were graded as anatomically successful (67%), based on the defined success parameters. There was a significant reduction in corneal neovascularization, which was accompanied by an improvement in pain though not photophobia or central corneal opacity post transplant. The transplantation protocol showed no measureable effect on visual acuity.ConclusionWe conclude that this standardized culture system and surgical approach is safe and effective in reducing corneal neovascularization. The technique is free from animal contaminants and maintains a large proportion of progenitor cells. Although this technique did not improve visual function, restoring a functional epithelial cell layer and reducing corneal neovascularization provides an improved platform for a penetrating keratoplasty to ultimately improve visual function.

Nanotechnology in Corneal Neovascularization Therapy—A Review

Nanotechnology is an up-and-coming branch of science that studies and designs materials with at least one dimension sized from 1-100 nm. These nanomaterials have unique functions at the cellular, atomic, and molecular levels. The term "nanotechnology" was first coined in 1974. Since then, it has evolved dramatically and now consists of distinct and independent scientific fields. Nanotechnology is a highly studied topic of interest, as nanoparticles can be applied to various fields ranging from medicine and pharmacology, to chemistry and agriculture, to environmental science and consumer goods. The rapidly evolving field of nanomedicine incorporates nanotechnology with medical applications, seeking to give rise to new diagnostic means, treatments, and tools. Over the past two decades, numerous studies that underscore the successful fusion of nanotechnology with novel medical applications have emerged. This has given rise to promising new therapies for a variety of diseases, especially cancer. It is becoming abundantly clear that nanotechnology has found a place in the medical field by providing new and more efficient ways to deliver treatment. Ophthalmology can also stand to benefit significantly from the advances in nanotechnology research. As it relates to the eye, research in the nanomedicine field has been particularly focused on developing various treatments to prevent and/or reduce corneal neovascularization among other ophthalmologic disorders. This review article aims to provide an overview of corneal neovascularization, currently available treatments, and where nanotechnology comes into play.

Comparison of the effects of bevacizumab and ranibizumab injection on corneal angiogenesis in an alkali burn induced model.

To investigate the effects of bevacizumab and ranibizumab on corneal neovascularization in an alkali burn-induced model of corneal angiogenesis. Fifteen Wistar albino rats were divided randomly into 3 groups after chemical cauterization of the cornea. The first group received a single dose of 0.1mL saline solution as a control group whereas second and third groups received a single dose of 2.5mg bevacizumab or 1mg ranibizumab by subconjunctival injection, respectively. After three weeks, the rat corneas were evaluated by biomicroscopy and corneal photographs were taken. The percentage of neovascularization area, length of the longest new vessel, corneal edema and corneal opacity scores were assessed. The analysis of digital photographs showed that the percentage of neovascularization area to the total corneal area, the length of the longest new vessel, corneal edema and opacity scores were significantly lower in both study groups compared to the control group (P<0.05). Additionally, the percentage of corneal neovascularization area, the length of the longest new vessel and corneal opacity score were less with bevacizumab than ranibizumab. Subconjunctival bevacizumab and ranibizumab treatments may be effective methods in reducing corneal neovascularization. Furthermore, bevacizumab is more effective than ranibizumab in the inhibition of corneal neovascularization.

Gene therapy for corneal dystrophies and disease, where are we?

We assess the studies on vector systems for delivery of transgenes to the cornea that have been published over the last year and summarize new work on the identification of specific transgenes for corneal diseases. Adeno-associated viral vectors are increasingly being successfully applied to the cornea, although transgene expression requires corneal epithelial debridement or intrastromal injection of the vector. Gene delivery platforms based on nanoparticles of chitosan or gold also show promise. Overexpression of vasoinhibin-1 or decorin, or siRNA-mediated blockade of the cannabinoid receptor CB1, can all reduce corneal neovascularization. Overexpression of decorin or matrix metalloproteinase 14 can reduce corneal fibrosis and haze, whereas overexpression of c-Met accelerates the epithelial wound healing. Induction of corneal endothelial cell replication by overexpression of E2F2, p16 or p21 can maintain or even increase corneal endothelial cell density in eye bank corneas. Overexpression of the antiapoptotic transgenes Bcl-xL or p35 significantly enhances corneal endothelial cell survival and reduces apoptosis in stored human corneas. Despite a wealth of information on the methods for the delivery of nucleic acids to the human cornea and ever-increasing information on the transgenes with substantial therapeutic potential, gene therapy for corneal disorders has yet to reach the clinic.

Role of miR-132 in Angiogenesis after Ocular Infection with Herpes Simplex Virus

MicroRNAs (miRNAs) are small regulatory molecules that control diverse biological processes that include angiogenesis. Herpes simplex virus (HSV) causes a chronic immuno-inflammatory response in the eye that may result in corneal neovascularization during blinding immunopathological lesion stromal keratitis (SK). miR-132 is a highly conserved miRNA that is induced in endothelial cells in response to growth factors, such as vascular endothelial growth factor (VEGF). In this study, we show that miR-132 expression was up-regulated (10- to 20-fold) after ocular infection with HSV, an event that involved the production of both VEGF-A and IL-17. Consequently, blockade of VEGF-A activity using soluble VEGF receptor 1 resulted in significantly lower levels of corneal miR-132 after HSV infection. In addition, low levels of corneal miR-132 were detected in IL-17 receptor knockout mice after HSV infection. In vivo silencing of miR-132 by the provision of anti-miR-132 (antagomir-132) nanoparticles to HSV-infected mice led to reduced corneal neovascularization and diminished SK lesions. The anti-angiogenic effect of antagomir-132 was reflected by a reduction in angiogenic Ras activity in corneal CD31-enriched cells (presumably blood vessel endothelial cells) during SK. To our knowledge, this is one of the first reports of miRNA involvement in an infectious ocular disease. Manipulating miRNA expression holds promise as a therapeutic approach to control an ocular lesion that is an important cause of human blindness.

Combined Use of Subconjunctival and Intracorneal Bevacizumab Injection for Corneal Neovascularization

To report on the safety and clinical use of combined subconjunctival and intracorneal bevacizumab for corneal neovascularization. The charts of 12 consecutive patients with corneal neovascularization who received combined subconjunctival and intracorneal injections of bevacizumab (2.5 mg/0.1 mL) were reviewed. Patients received 1 to 3 injections of 2.5 mg of bevacizumab (1.25 mg/0.05 mL subconjunctival and 1.25 mg/0.05 mL intrastromal). Morphological changes were assessed clinically by 1 investigator. Combined subconjunctival and intracorneal injections of bevacizumab were effective and well-tolerated. No significant ocular or systemic adverse events were observed during 6.4 months (range, 0.25-22 months) of follow-up. All patients showed a reduction in the neovascularized area. Short-term results suggest that combined subconjunctival and intracorneal injections of bevacizumab are an effective method for reducing corneal neovascularization. It may be a useful option or adjunct to other treatments in stabilizing or improving vision.