Anti-VEGF therapy with bevacizumab for anterior segment eye disease

Biomimetic nanocomplex based corneal neovascularization theranostics

Corneal neovascularization (CNV) is a major cause of blindness worldwide. However, the recent drug treatment is limited by repeated administration and low drug bioavailability. In this work, SU6668 (an inhibitor of receptor tyrosine kinases) and indocyanine green (ICG) are loaded onto poly(lactic-co-glycolic acid) (PLGA) nanoparticles, and then coated with anti-VEGFR2 single chain antibody (AbVr2 scFv) genetically engineered cell membrane vesicles. The nanomedicine is delivered via eye drops, and the hyperthermia induced by laser irradiation could block the blood vessels. Meanwhile, the photothermal effect can also cause the degradation of nanomaterials and release chemotherapeutic drugs in the blocked area, thereby continuously inhibit the neovascularization. Furthermore, SU6668 could inhibit the expression of heat shock protein 70 (HSP70), promoting the cell death induced by photothermal effect. In conclusion, the combination of photothermal and chemotherapy drugs provides a novel, effective and safe approach for the treatment of CNV.

Adjunctive bevacizumab therapy in an equine corneal stromal invasive squamous cell carcinoma with a 53-months follow-up

A 17-year-old Appaloosa mare was referred for evaluation of presumed refractory keratitis of the left eye. Gross examination revealed ocular discomfort and corneal neovascularization with a nasal focal opacification affecting approximately 40% of the corneal surface. On ophthalmic examination, extensive subepithelial to mid-stromal vascular branching accompanied by a homogeneous white, dense opacification, which affected up to 80% of the total corneal thickness, were apparent. Signs of concurrent uveitis were absent. Deep-stromal lamellar keratectomy with a conjunctival pedicle graft was performed under general anesthesia. Histopathology confirmed a poorly differentiated corneal stromal invasive squamous cell carcinoma (SI-SCC) with neoplastic cell extension to the surgical margins. Postoperatively, 4 topical mitomycin C 0.04% chemotherapy cycles combined with oral firocoxib therapy were initiated. Seven months after surgery, regrowth of the SI-SCC was clinically suspected. A total volume of 1 ml bevacizumab 2.5% was administered in the standing sedated horse via 3 mid-stromal corneal injections. Four weeks later, intrastromal bevacizumab injections (ISBIs) were repeated, however, this time the solution was injected directly into the main corneal vessel branches.Seven weeks after the second ISBIs, the left eye was comfortable and significant remission of corneal vascularization and opacity was recognized. No recurrence has been noted for a follow-up period of more than 53 months.Equine SI-SCC usually has a very poor prognosis for globe maintenance. To the authors' knowledge this is the first report of well-tolerated intrastromal antivascular endothelial growth factor adjunctive therapy with bevazicumab 2.5% and SI-SCC resolution after a multimodal treatment approach.

Drug Distribution After Intravitreal Injection: A Mathematical Model

Purpose

Intravitreal injection of drugs is commonly used for treatment of chorioretinal ocular pathologies, such as age-related macular degeneration. Injection causes a transient increase in the intraocular volume and, consequently, of the intraocular pressure (IOP). The aim of this work is to investigate how intravitreal flow patterns generated during the post-injection eye deflation influence the transport and distribution of the injected drug.

Methods

We present mathematical and computational models of fluid motion and mass transport in the vitreous chamber during the transient phase after injection, including the previously unexplored effects of globe deflation as ocular volume decreases.

Results

During eye globe deflation, significant fluid velocities are generated within the vitreous chamber, which can possibly contribute to drug transport. Pressure variations within the eye globe are small compared to IOP.

Conclusions

Even if significant fluid velocities are generated in the vitreous chamber after drug injection, these are found to have negligible overall effect on drug distribution.

Bevacizumab Efficiently Inhibits VEGF-Associated Cellular Processes in Equine Umbilical Vein Endothelial Cells: An In Vitro Characterization

Anti-VEGF agents were found to have clinical implications for the successful treatment of vascular-driven diseases in humans. In this study, a detailed biological characterization of bevacizumab in a variety of in vitro assays was carried out to determine the effect of bevacizumab on equine umbilical vein endothelial cells (EqUVEC). EqUVECs were harvested from umbilical cords of clinically healthy horses and exposed to different concentrations (1, 2, 4, 6, 8 mg/mL) of bevacizumab (Avastin®). Assays concerning the drug's safety (cell viability and proliferation assay) and efficacy (cell tube formation assay, cell migration assay, and Vascular endothelial growth factor (VEGF) expression) were carried out reflecting multiple cellular processes. Bevacizumab significantly decreased VEGF expression at all concentrations over a 72 h period. No cytotoxic effect of bevacizumab on EqUVECs was observed at concentrations of 4 mg/mL bevacizumab or lower. Incubated endothelial cells showed delayed tube formation and bevacizumab efficiently inhibited cell migration in a dose-dependent manner. Bevacizumab potently inhibits VEGF-induced cellular processes and could be a promising therapeutic approach in vascular-driven diseases in horses.

Organic Nanocarriers for Bevacizumab Delivery: An Overview of Development, Characterization and Applications

Bevacizumab (BCZ) is a recombinant humanized monoclonal antibody against the vascular endothelial growth factor, which is involved in the angiogenesis process. Pathologic angiogenesis is observed in several diseases including ophthalmic disorders and cancer. The multiple administrations of BCZ can cause adverse effects. In this way, the development of controlled release systems for BCZ delivery can promote the modification of drug pharmacokinetics and, consequently, decrease the dose, toxicity, and cost due to improved efficacy. This review highlights BCZ formulated in organic nanoparticles providing an overview of the physicochemical characterization and in vitro and in vivo biological evaluations. Moreover, the main advantages and limitations of the different approaches are discussed. Despite difficulties in working with antibodies, those nanocarriers provided advantages in BCZ protection against degradation guaranteeing bioactivity maintenance.

Effect of Topical Instillation of Pegaptanib Sodium Upon Inflammatory Corneal Neovascularization in Rabbits

Purpose: To evaluate the effect of topical instillation of pegaptanib sodium upon inflammatory angiogenesis induced in the rabbit cornea by alkaline cauterization. Methods: Inflammatory angiogenesis was induced by alkaline (sodium hydroxide) cauterization in the corneas of 29 male New Zealand rabbits. The animals were divided into 4 groups: a control group treated with 0.5% carboxymethylcellulose sodium eye drops, a group treated with 1.0% prednisolone acetate eye drops, a group treated with 0.5% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium, and a group treated with 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium. After cauterization, eye drops were administered every 12 hours for 21 days. The animals were evaluated every 3 days after cauterization, and the newly formed vessels were quantified from photographs. The treatment effectiveness was analyzed with 3 parameters of antiangiogenic response: neovascularization area (NA), total vascular length (TVL), and number of blood vessels (BVN). Results: Average NA, TVL, and BVN values were significantly higher in both pegaptanib groups than in the prednisolone group. A nonstatistically significant reduction in parameters on days 18 and 21 was the minimum achieved in both pegaptanib groups. The efficacy of the treatments in relation to the control was significantly greater in the prednisolone group than in the 0.5% pegaptanib group or the 1.0% pegaptanib group (P < 0.001). Conclusion: Topical instillation of 0.5% and 1.0% pegaptanib sodium diluted in 15 mL 0.5% carboxymethylcellulose sodium had no inhibitory effect on corneal neovascularization in this rabbit model.

Anti-VEGF Treatment in Corneal Diseases

BACKGROUND

Corneal neovascularization (CN) is a clue feature of different ocular pathological conditions and can lead to corneal edema and opacification with subsequent vision loss. Vascular endothelial growth factor (VEGF), which plays a key role in new vessels formation, proliferation and migration, was found to be up-regulated in these conditions. Nowadays, it is possible to downregulate the angiogenic process by using anti-VEGF agents administered by different routes.

OBJECTIVE

To evaluate the efficacy, safety and possible future directions of anti-VEGF agents used for the treatment of CNV owing to different aetiologies.

METHODS

A computerized search of articles dealing with the topic of anti-VEGF therapy in CN was conducted in PubMed, Scopus and Medline electronic databases. The following key phrases were used: anti-VEGF agents, corneal neovascularization, bevacizumab, ranibizumab, vascular endothelial growth factor, angiogenesis.

RESULTS

The use of anti-VEGF therapy in the treatment of CN reduced pathological vessel density without causing significant side effects. Various administration routes such as topical, subconjunctival and intrastromal ones are available, and the choice depends on patient and disease characteristics. Much more effectiveness is achieved in case of early administration before mature and wellestablished vessels take place. A combined approach between various drugs including anti-VEGF agents should be adopted in those cases at higher risk of neovascularization recurrence such as chronic long-standing diseases where ischemic and inflammatory stimuli are not definitively reversed.

CONCLUSION

The efficacy and safety of anti-VEGF agents support their adoption into the daily clinical practice for the management of CN.

Bevacizumab-Conjugated Quantum Dots: In Vitro Antiangiogenic Potential and Biosafety in Rat Retina

Purpose: Disturbances that affect the inside of the eyeball tend to be highly harmful since they compromise the homeostasis of this organ. Alongside this, the eyeball has several anatomical barriers that prevent the entry of substances. This way, diseases that affect the retina are among those that present greater difficulty in the treatment. In many cases, abnormal proliferation of blood vessels (neovascularization) occurs from the lower layers of the retina. This process damages its structure physiologically and anatomically, causing the rapid and irreversible loss of visual capacity. This work aims to develop nanosuspensions of quantum dots (QDs) conjugated to bevacizumab. Methods: Two types of QDs were produced by aqueous route, stabilized with chitosan conjugated to bevacizumab. The antiangiogenic activity was evaluated in the chorioallantoic membrane model, in which results indicated discrete activity at the doses tested. Samples were assessed for their biosafety in animals, after intravitreal administration, by means of electroretinography (ERG), intraocular pressure (IOP) measurement, histological, morphometric, and immunohistochemical evaluation. Results: No significant alterations were detected in ERG that suggests damage to retinal function by the samples. No significant changes in IOP were also detected. The histological sections did not show signs of acute inflammation, although there was evidence of late retinal damage. The immunohistochemical analysis did not detect any apoptotic bodies. Conclusion: Preliminary results suggest that QDs present potential applicability in ocular therapy, and it is necessary to better characterize their in vivo behavior and to optimize their dosage.

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.

Corneal graft melting: a systematic review

Corneal graft melting is a severe complication of keratoplasty. This review is to summarize the incidence, the pathogenesis, the risk factors, the prognosis and the prevention of corneal graft melting after keratoplasty. We systematically searched PubMed, Web of Science and WanFang database to retrieve potentially eligible articles about relevant clinical reports and animal experiments. We read the full texts to identify eligible articles. The selection of studies and data extraction were performed independently by two reviewers. In conclusion, the pathogenesis of corneal graft melting is complicated, and many risk factors are closely related to corneal graft melting. Analysis of pathogenesis and risk factors of corneal graft melting can facilitate the development of targeted therapies to better guide clinical practice.

Long-term outcome of using Prosthetic Replacement of Ocular Surface Ecosystem (PROSE) as a drug delivery system for bevacizumab in the treatment of corneal neovascularization

PURPOSE

To report the long-term outcome of Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) for delivery of bevacizumab in the treatment of corneal neovascularization (KNV).

METHODS

Retrospective, non-comparative, interventional case series of 13 sequential patients treated for KNV at the BostonSight between 2006 and 2017. In all cases, PROSE treatment was initiated for management of ocular surface disease and patients wore PROSE consistently on a daily wear basis prior to bevacizumab treatment. Patients applied a drop of 1% preservative free bevacizumab to the reservoir of PROSE device twice daily. Patients continued with daily wear of the device during treatment and afterwards.

RESULTS

13 patients (8 female and mean age of 45 years) are included with a mean follow-up of 5.1 years (range 6 months-11 years). Underlying ocular diagnoses included Stevens-Johnson syndrome (7), ocular chronic graft-versus-host disease (2), corneal transplant (2), contact lens-related corneal ulcer and limbal stem cell deficiency (1), and familial dysautonomia (1). Median duration of bevacizumab use was 6 months (range 3 months-10 years). Twelve cases (92%) had regression of KNV and 10 cases (77%) had improved best-corrected visual acuity (BCVA) with treatment. Median BCVA improved from -1.1 (LogMAR) at baseline, to -0.66 at end of bevacizumab treatment, and remained -0.63 at last follow-up (P = 0.047). KNV progressed in one eye after discontinuation of bevacizumab. There were no ophthalmic or systemic complications.

CONCLUSIONS

Topical bevacizumab used in PROSE is effective in treating KNV and improving vision. Long-term follow-up reveals durable response and no complications.

Effects of ranibizumab (Lucentis®) and bevacizumab (Avastin®) on human corneal endothelial cells

Background

Ingrowth of newly formed blood and lymph vessels (angiogenesis) from the limbus region into the cornea can be treated successfully by subconjunctival application of antiangiogenic agents. Currently, there are several angiogenesis inhibitors from various manufacturers available, such as vascular endothelial growth factor (VEGF) antibodies. The aim of the study was to investigate potential cytotoxic effects of two anti-VEGF agents, ranibizumab (Lucentis®) and bevacizumab (Avastin®) on the human corneal endothelium.

Methods

Human donor corneas, not suitable for corneal transplantation, were organ-cultured in the presence of either ranibizumab (Lucentis®) or bevacizumab (Avastin®) at different concentrations (group 1: 250 μg / ml, group 2: 25 μg / ml, group 3: 2.5 μg / ml) for a period of up to 4 weeks. Microscopic imaging for endothelial cell counting, detection of morphologic alterations of the endothelium, and molecular biology testing (Enzyme-linked Immunosorbent Assay [ELISA]) for metabolic changes was performed.

Results

Background-corrected results showed neither a significant lactate dehydrogenase (LDH) change with increasing culturing time nor a significant difference between ranibizumab (Lucentis®) and bevacizumab (Avastin®) treatment. The endothelial cell density revealed also no statistically significant difference between the two treatment groups with ranibizumab (Lucentis®) and bevacizumab (Avastin®) at all concentrations tested in this study.

Conclusions

In this study, the anti-angiogenic agents ranibizumab (Lucentis®) and bevacizumab (Avastin®) demonstrated no cytotoxic effects on the corneal endothelium of human organ-cultured donor corneas over the limited study time period of 4 weeks. However, based on the study design (in-vitro) and the limited follow-up period, no conclusions on potential long-term effects can be drawn.

Vascular Endothelial Growth Factor (VEGF) Serological and Lacrimal Signaling in Patients Affected by Vernal Keratoconjunctivitis (VKC)

Background

Vernal keratoconjunctivitis (VKC) is a rare inflammatory disease involving the ocular surface, with seasonally exacerbated symptoms. Both type-1 and type-4 hypersensitivity reactions play a role in the development of VKC.

Purpose

The aim of the present study was to assess the presence and evaluate the concentration of the vascular endothelial growth factor (VEGF) in tear and blood samples from patients with VKC, during the acute phase, based on the histopathological vasculostromal structure of the tarsal papillae.

Methods

Two groups of children aged between 6 and 16 years of life were enrolled: 21 patients (16 males, 76%) affected by VKC, tarsal or mixed form, and 13 healthy children (5 males, 38%) used as controls. Blood and tear samples were obtained from all patients, in order to specifically assess the presence of VEGF. Statistical analyses were performed with one-way ANOVA, followed by post hoc comparisons with the Bonferroni tests. Pearson's correlation was chosen as statistical analysis to assess the relationship between the expression levels of VEGF in tears and blood and the clinical parameters measured.

Results

Comparing the 2 groups for VEGF concentration, a statistically significant difference was found in tear samples: the mean value was 12.13 pg/mL (±5.54 SD) in the patient group and 7 pg/ml (±4.76 SD) in controls (p < 0.05). However, no statistically significant difference was found when comparing VEGF concentration in blood samples (p > 0.05), with a mean value of 45.17 pg/mL (±18.67 SD) in VKC patients and 38.08 pg/mL (±19.43 SD) in controls.

Conclusions

This pilot study highlights the importance of lacrimal and vascular inflammatory biomarkers that can be detected in VKC patients during the acute phase, but not in healthy children. The small group of patients warrants additional studies on a larger sample, not only to further investigate the role of VEGF but also to evaluate the angiogenic biomarkers before and after topical treatment.

Selective IKK2 inhibitor IMD0354 disrupts NF-κB signaling to suppress corneal inflammation and angiogenesis

Corneal neovascularization is a sight-threatening condition caused by angiogenesis in the normally avascular cornea. Neovascularization of the cornea is often associated with an inflammatory response, thus targeting VEGF-A alone yields only a limited efficacy. The NF-κB signaling pathway plays important roles in inflammation and angiogenesis. Here, we study consequences of the inhibition of NF-κB activation through selective blockade of the IKK complex IκB kinase β (IKK2) using the compound IMD0354, focusing on the effects of inflammation and pathological angiogenesis in the cornea. In vitro, IMD0354 treatment diminished HUVEC migration and tube formation without an increase in cell death and arrested rat aortic ring sprouting. In HUVEC, the IMD0354 treatment caused a dose-dependent reduction in VEGF-A expression, suppressed TNFα-stimulated expression of chemokines CCL2 and CXCL5, and diminished actin filament fibers and cell filopodia formation. In developing zebrafish embryos, IMD0354 treatment reduced expression of Vegf-a and disrupted retinal angiogenesis. In inflammation-induced angiogenesis in the rat cornea, systemic selective IKK2 inhibition decreased inflammatory cell invasion, suppressed CCL2, CXCL5, Cxcr2, and TNF-α expression and exhibited anti-angiogenic effects such as reduced limbal vessel dilation, reduced VEGF-A expression and reduced angiogenic sprouting, without noticeable toxic effect. In summary, targeting NF-κB by selective IKK2 inhibition dampened the inflammatory and angiogenic responses in vivo by modulating the endothelial cell expression profile and motility, thus indicating an important role of NF-κB signaling in the development of pathologic corneal neovascularization.

Transfer of single dose of intravitreal injection of ranibizumab and bevacizumab into milk of sheep

AIM

To investigate whether single-dose intravitreal injections of bevacizumab and ranibizumab transfer into milk.

METHODS

This study included lactating 12 sheep and a single 3-month old suckling lamb of each sheep. Two groups consisting of 6 sheep and their lambs were constituted; the ranibizumab group and the bevacizumab group before the administration of intravitreal injections, blood and milk samples were obtained from all sheep and, following the injections, blood and milk samples of all sheep and blood samples of all lambs were collected at regular time points. Serum and milk concentrations of bevacizumab and ranibizumab were measured using an enzyme-linked immunosorbent assay (ELISA) kit. The limit of determination was 0.9 ng/mL for bevacizumab and 0.62 ng/mL for ranibizumab.

RESULTS

At 6h after intravitreal injections, bevacizumab concentration was above the limit of determination in the blood of all sheep. At 3wk, when the study was terminated, bevacizumab concentrations were high in 4 sheep. Even though bevacizumab concentrations in milk showed fluctuations, the drug transferred into the milk of all sheep at detectable concentrations. Ranibizumab drug concentrations in the blood and milk of sheep and those in the blood of lambs were below the limit of determination by the ELISA kit.

CONCLUSION

This sheep model study demonstrate that intravitreal injection of ranibizumab, which did not transfer into the milk of sheep and suckling lambs, is safer than bevacizumab during lactation period.

Management of high-risk corneal transplantation

The cornea is the most commonly transplanted tissue in medicine. The main cause of corneal graft failure is allograft rejection. The incidence of graft rejection depends on the presence of high-risk characteristics, most notably corneal neovascularization. Although corneal grafting has high success rates in the absence of these risk factors, high-risk keratoplasty is associated with low success rates because of a high incidence of immune-mediated graft rejection. To improve the survival of high-risk corneal transplantation, various preoperative, intraoperative, and postoperative measures can be considered; however, the key step in the management of these grafts is the long-term use of local and/or systemic immunosuppressive agents. Although a number of immunosuppressive agents have been used for this purpose, the results vary significantly across different studies. This is partly due to the lack of an optimized method for their use, as well as the lack of a precise stratification of the degree of risk in each individual patient. New targeted biologic treatments, as well as tolerance-inducing methods, show promising horizons in the management of high-risk corneal transplantation in near future.

Topical Bevacizumab for the Treatment of Ocular Surface Squamous Neoplasia

PURPOSE

To determine the efficacy and safety of topical bevacizumab treatment in patients with ocular surface squamous neoplasia (OSSN).

METHODS

Six eyes of 6 patients with primary OSSN confirmed by impression cytology received topical 5 mg/mL bevacizumab 4 times daily for a period of 8 weeks. Patients were evaluated in 2-week intervals. Digital photography images were obtained at each visit and changes in the size of the lesions were analyzed by image analysis software.

RESULTS

The mean age of the patients was 66 ± 13 (± SD) years. Four tumors were nasal in origin and 2 tumors were temporal. The mean reduction observed in the lesion area was 43% ± 24.2% (range, 20%-71%) in the first month and 68% ± 29.7% (range, 42%-100%) in the second month when compared with the baseline area. Four patients required tumor excision at the end of the treatment period. Surgical treatment was not necessary in 2 patients due to complete disappearance of the tumor, which was confirmed by impression cytology. The visual acuity was stable in all patients and no systemic or visual side effects were observed during the study period.

CONCLUSIONS

Topical bevacizumab is effective as a neoadjuvant therapy combined with surgical excision for the treatment of OSSN. Topical bevacizumab may be used before surgery to decrease the size of the excision. Excision may be unnecessary in responsive patients.

Inhibition of pathological corneal neovascularization by a small peptide derived from human apolipoprotein (a) Kringle V

PURPOSE

The aim of this study was to evaluate the antiangiogenic activity of AU6, a novel 6-amino acid peptide derived from Kringle V of human apolipoprotein (a).

METHODS

RF/6A rhesus macaque choroid endothelial cells were used for in vitro studies. MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assays and modified Boyden chamber and Matrigel assays were used to evaluate the inhibitory effect of AU6 on vascular endothelial growth factor (VEGF)-stimulated endothelial cell functions, including cell proliferation, migration, and tube formation. The chick chorioallantoic membrane model, micropocket corneal neovascularization (CNV) model, and alkali burn CNV model were evaluated in vivo. Bevacizumab (Avastin), the VEGF-neutralizing antibody, and a scrambled peptide (AU6s) were used as positive and negative controls, respectively.

RESULTS

AU6 inhibited VEGF-induced RF/6A cell migration, proliferation, and tube formation. It also reduced pathological neovascularization in the chorioallantoic membrane model and in the 2 CNV models, that is, the mouse corneal micropocket model and the rat cornea alkali burn model.

CONCLUSIONS

AU6 effectively inhibited pathogenic CNV. This novel peptide shows potential as a new treatment for ocular neovascularization.

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.

Current knowledge and trends in age-related macular degeneration: today's and future treatments

PURPOSE

To address the most dynamic and current issues concerning today's treatment options and promising research efforts regarding treatment for age-related macular degeneration. This review is aimed to serve as a practical reference for more in-depth reviews on the subject.

METHODS

An online review of the database PubMed and Ovid were performed, searching for the key words age-related macular degeneration, AMD, VEGF, treatment, PDT, steroids, bevacizumab, ranibizumab, VEGF-trap, radiation, combined therapy, as well as their compound phrases. The search was limited to articles published since 1985. All returned articles were carefully screened, and their references were manually reviewed for additional relevant data. The web page www.clinicaltrials.gov was also accessed in search of relevant research trials.

RESULTS

A total of 363 articles were reviewed, including 64 additional articles extracted from the references. At the end, only 160 references were included in this review.

CONCLUSION

Treatment for age-related macular degeneration is a very dynamic research field. While current treatments are mainly aimed at blocking vascular endothelial growth factor, future treatments seek to prevent vision loss because of scarring. Promising efforts have been made to address the dry form of the disease, which has lacked effective treatment.

Long-term outcomes of Fine Needle Diathermy for established corneal neovascularisation

BACKGROUND/AIMS

Corneal neovascularisation (CoNV) can lead to significant ocular comorbidity with reduction in vision and cosmesis. A number of techniques have been described to reduce CoNV, but these can be expensive. Our study aimed to determine the safety, efficacy and long-term outcomes of fine needle diathermy (FND) for CoNV.

METHODS

A 5-year retrospective study identified all cases of FND. Indications, intraoperative complications, and postoperative visual acuity, after treatment and retreatments, were documented, along with the procedure time. Evidence of regression and number of retreatments were identified.

RESULTS

56 eyes from 52 patients underwent FND for CoNV. The main indications included herpes simplex keratitis (HSK) (53%, n=25) and microbial keratitis/peripheral ulcerative keratitis (13%, n=6). Pretreatment acuity was significantly correlated with extent of CoNV (p=0.044). One complication was noted during the procedure-an intrastromal and subconjunctival haemorrhage (rate 2%). 68.1% of patients demonstrated regression at first follow-up (mean 6.9 weeks), and 89.3% (n=42) showed regression with two or less treatments. Mean post-FND acuity was 0.72 (range -0.2-3.0) vs 0.82 (-0.2-3.0) preprocedure (p=0.08). VA improved in the HSK subgroup (p=0.012). Mean follow-up was 18.9 months (range 1-56 months).

CONCLUSIONS

In the largest case series reported, FND appears to be a safe and effective technique in the long term to induce regression of CoNV, with significant improvement in the VA of patients with HSK.

Natural course of anterior segment ischemia after disinsertion of extraocular rectus muscles in an animal model

PURPOSE

To compare the frequency and severity of anterior segment ischemia (ASI) after disinsertion of extraocular rectus muscles in a rabbit eye model.

METHODS

The rectus muscles of eyes of 84 rabbits were removed. In 42 rabbits one eye underwent three-muscle surgery, whereas the fellow eye underwent two-muscle surgery. In the other 42 rabbits, one eye underwent three-muscle surgery and the fellow eye four-muscle surgery. The surgery included disinsertion together with extirpation of the anterior 10 mm of the muscle. Each eye was examined daily to detect the presence of ASI. Anti-inflammatory eyedrops were not used in any subject. The severity of inflammation and time to complete resolution of inflammatory signs were documented. After inflammation resolved, both eyes of each rabbit were enucleated and studied by a pathologist.

RESULTS

The incidence of ASI was 9.5% in the two-muscle group, 31% in the three-muscle group, and 50% in the four-muscle group (P =0.001). ASI eyes all developed signs on the first postoperative day. Inflammation resolved in 4-38 days. The incidence of ASI increased significantly with the number of muscles operated on. Permanent complications were rare and histopathology results were normal in most cases.

CONCLUSIONS

Inflammation resolved spontaneously in all involved eyes without intervention and only minor clinical or pathologic changes were noted. One eye, however, developed severe sequela but was still preserved. The severity of ASI was directly correlated to the number of operated rectus muscles. Our findings suggest a self-limited nature of ASI in this rabbit model.

Lack of association between VAP-1/SSAO activity and corneal neovascularization in a rabbit model

The aim of this study is to determine the efficacy of a potent and specific vascular adhesive protein-1/semicarbazide-sensitive amine oxidase (VAP-1/SSAO) inhibitor, LJP 1207, as a potential antiangiogenic and anti-inflammatory agent in the therapy of corneal neovascularization. Corneal neovascularization was induced with intrastromal suturing in rabbits (n = 20). Topical treatment with VAP-1/SSAO inhibitor LJP 1207 (n = 5, 4 times a day), bevacizumab (n = 5, daily), their combination (n = 5) and vehicle only (n = 5, 4 times a day) were applied postoperatively for 2 weeks. The development and extent of corneal neovascularization were evaluated by digital image analysis. At the end of the observation period, the level of corneal and serum VAP-1/SSAO activity was measured fluorometrically and radiochemically. The corneal VAP-1/SSAO activity was significantly elevated in the suture-challenged vehicle-treated group (3,075 ± 1,009 pmol/mg/h) as compared to unoperated controls (464.2 ± 135 pmol/mg/h, p < 0.001). Treatment with LJP 1207 resulted in slower early phase neovascularization compared to vehicle-treated animals (not significant). At days 7-14, there was no significant difference in the extent of corneal neovascularization between inhibitor- and vehicle-treated corneas, even though inhibitor treatment caused a normalization of corneal VAP-1/SSAO activity (885 ± 452 pmol/mg/h). Our results demonstrate that the significant elevation of VAP-1/SSAO activity due to corneal injury can be prevented with VAP-1/SSAO inhibitor LJP 1207 treatment. However, normalization of VAP-1/SSAO activity in this model does not prevent the development of corneal neovascularization.

Combined scraping, coagulation, and subconjunctival bevacizumab in Descemet stripping automated endothelial keratoplasty for bullous keratopathy

PURPOSE

This study evaluated the clinical outcomes of a combined method of scraping corneal epithelium, coagulating vessels, and subconjunctival bevacizumab in Descemet stripping automated endothelial keratoplasty (DSAEK) for bullous keratopathy with corneal neovascularization (NV).


METHODS

The study included patients with bullous keratopathy undergoing DSAEK. Indications for DSAEK were advanced pseudophakic bullous keratopathy with superficial and deep corneal vascularization and failed corneal grafts. Patients were treated by scraping the corneal epithelium and lightly coagulating the corneal superficial stromal NV and the feeding vessels in the sclera, with a subconjunctival bevacizumab injection at the end of surgery. Subconjunctival and perilimbal bevacizumab dose of 2.5 mg/0.1 mL/affected quadrant was injected at the site of NV in each patient at the end of surgery. One or 2 injections were applied. At each visit, a full eye examination with photographic documentation was performed. Mean follow-up period was 32 (24-36) months.


RESULTS

Eight eyes of 8 patients with high-risk corneal transplantation and corneal NV were included in this noncomparative interventional case series. The original corneal NV disappeared in all patients immediately after surgery. No patient in the series had recurrent corneal NV or rejection during at least 24 months of follow-up. 


CONCLUSIONS

. The combination of scraping, coagulating, and bevacizumab injection in DSAEK is an effective method to treat corneal NV in corneal transplantation for bullous keratopathy.