Subconjunctival bevacizumab for corneal neovascularization

Acta Ophthalmol. 2010: 88: 868–871

Abstract.

Purpose: This work aimed to study and evaluate the effect of subconjunctival bevacizumab injection in patients with corneal neovascularization (CNV) resulting from different ocular surface disorders. Methods: Ten eyes with CNV caused by different ocular surface disorders were studied. All eyes had both major and minor vessel CNV caused by factors such as healed corneal ulcers, long‐standing chronic inflammatory diseases and corneal ischaemia (caused by contact lenses). All eyes received a single subconjunctival injection of 2.5 mg (0.1 ml) bevacizumab. Morphological changes in the major and minor vessels were evaluated using slit‐lamp biomicroscopy and corneal photography. Results: Conspicuous recession of the minor vessels of CNV was observed in all eyes at 2 weeks post‐injection. The extent of CNV of the major vessels was significantly decreased at 2 weeks post‐injection. The level of CNV continued to decrease noticeably for 3 months and then stabilized for the remainder of the 6‐month follow‐up period. Parameters used for evaluation included the total area of CNV, which amounted to 14.0 ± 5.4% of the corneal surface pre‐injection, compared with 9.4 ± 3.9% post‐injection (p < 0.01), reflecting a mean decrease in CNV of 33 ± 8%, and the extent of neovascularization, which decreased from 4.3 ± 1.5 clock hours pre‐injection to 2.4 ± 1.1 clock hours post‐injection (p < 0.01). During the 6‐month follow‐up, none of the 10 eyes showed any complication that could be related to subconjunctival bevacizumab injection. Conclusions: Bevacizumab can be used safely and effectively for CNV resulting from different ocular surface disorders. It represents an effective treatment for minor vessel neovascularization caused by long‐standing chronic inflammation (e.g. trachoma) or long‐standing corneal ischaemia (e.g. contact lenses), as well as for major vessel neovascularization resulting from different causes. Bevacizumab was well tolerated over the 6‐month follow‐up period.     

Subconjunctival bevacizumab for corneal neovascularization

Objective To report the efficacy of subconjunctival bevacizumab injection in patients with corneal neovascularization (NV). Methods This retrospective interventional case study included two eyes of two patients with corneal NV due to aqueous-deficient dry eye with filamentary keratitis in the first case, and corneal graft failure in the second case. Patients received a subconjunctival injection of 2.5 mg (0.1 ml) bevacizumab. Morphologic changes were investigated by slit-lamp biomicroscopy and corneal photography. Results Corneal NV was dramatically regressed a week after injection in the first case. In the second case, minor vessels were regressed while the major one did not. No infection or inflammation was observed. No relapse was seen within the follow-up of two to three months. Conclusion Subconjunctival injection of bevacizumab may offer an additional strategy for the treatment of corneal NV.     

Subconjunctival bevacizumab injection for corneal neovascularization

PURPOSE: To report on the clinical use of subconjunctival bevacizumab in patients with corneal neovascularization. METHODS: The charts of 10 consecutive patients with corneal neovascularization who received subconjunctival injections of bevacizumab (2.5 mg/0.1 mL) were reviewed. Digital photographs of the cornea were graded by 2 masked observers for density, extent, and centricity of corneal vascularization. Image analysis was used to determine the area of cornea covered by neovascularization as a percentage of the total corneal area. RESULTS: No significant ocular or systemic adverse events were observed during 3.5 +/- 1.1 months of follow-up. Seven patients showed partial regression of vessels. The extent decreased from 6.0 +/- 1.2 (SD) clock hours before the injection to 4.6 +/- 1.0 clock hours after bevacizumab injection (P = 0.008). Density decreased from 2.7 +/- 0.2 to 1.9 +/- 0.3, respectively. (P = 0.007). No change was noticed in the centricity of corneal vessels. Corneal neovascularization covered, on average, 14.8% +/- 2.5% (SD) of the corneal surface before the injections, compared with 10.5% +/- 2.8% (P = 0.36, t test) after bevacizumab injection. Therefore, bevacizumab decreased corneal neovascularization by 29%. CONCLUSIONS: Short-term results suggest that subconjunctival bevacizumab is well tolerated and associated with a partial regression of corneal 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.     

Bevacizumab对大鼠角膜新生血管的抑制作用

目的 观察bevacizumab对角膜新生血管的抑制作用.方法 选取鼠龄6～8周、体质量(180±10)g的雄性Wistar大鼠40只,建立碱烧伤角膜新生血管模型;将大鼠随杌分为3个不同剂量药物治疗组(实验组)和1个对照组,每组10只(20眼),大鼠角膜碱烧伤后分别给予结膜下注射不同剂量(0.5 mg、1.0 mg、2.0 mg)的bevacizumab,对照组注入生理盐水;然后进行角膜新生血管的各项数据观察,观察期为16 d,主要观察项目包括各组角膜新生血管的生长情况;计算角膜新生血管的生长面积;碱烧伤后第7天和第16天后采集角膜,标本行组织病理学检测和免疫组织化学检测,第16天,计算平均OD值;评价药物对角膜新生血管的抑制效果.结果 碱烧伤后第7天、第14天,实验组与对照组新生血管面积比较差异均有统计学意义(均为P＜0.05);组织病理学检测发现各实验组炎性细胞浸润、新生血管形成均明显轻于对照组.对照组血管内皮生长因子(vascular endothelial growth factor,VEGF)染色明显增强,实验组的表达明显减弱.碱烧伤后第16天,实验组与对照组比较,VEGF染色阳性细胞数和VEGF平均OD值差异均有统计学意义(均为P＜0.05).碱烧伤后第7天、第16天大鼠角膜CD34的免疫组织化学检测结果及新生血管密度计数方面,实验组和对照组比较差异均有统计学意义(均为P＜0.05).结论 结膜下注射一定浓度的bevacizumab对大鼠角膜碱烧伤后的新生血管生长有抑制作用.     

Intrastromal corneal ring segments for management of keratoconus

Keratoconus is a progressive corneal ectasia, which can be managed both by conservative measures like glasses or contact lenses in non-progressive cases or surgical procedures like collagen crosslinking (CXL) with or without adjuvant measures like intrastromal corneal rings segments (ICRS) or topography guided ablation. Various kinds of ICRS are available to the surgeon, but it is most essential to be able to plan the implantation of the ring to optimize outcomes.

Aims:

The aim of this study is to evaluate the visual outcome and progression in patients of keratoconus implanted with ICRS.

Materials and Methods:

Two different types of ICRS-Intacs (Addition Technology) and Kerarings (Mediphacos Inc.) were implanted in 2 different cohorts of patients and were followed-up to evaluate the outcome of the procedure. All patients underwent a complete ocular examination including best spectacle corrected visual acuity, slit lamp examination fundus examination, corneal topography and pachymetry. The ICRS implantation is done with CXL to stop the progression of the disease. Improvement in uncorrected visual acuity (UCVA), best spectacle corrected visual acuity and topographic changes were analyzed.

Results:

A significant improvement in keratometry and vision was seen in both groups.

Conclusion:

ICRS have been found to reduce corneal irregularity and flatten keratometry with improvement in UCVA and best corrected visual acuity.     

Subconjunctival bevacizumab injection for corneal neovascularization in recurrent pterygium

PURPOSE: We report on the use of subconjunctival bevacizumab on corneal vessel density in recurrent pterygia. METHODS: The charts of 5 patients with recurrent pterygium, who received subconjunctival injections of bevacizumab (2.5 mg/0.1 ml) were retrospectively reviewed. Ophthalmic evaluation included Snellen visual acuity (VA), tonometry and complete examination before the injection and at 1 week and 1 and 3 months thereafter. Digital photographs of the eyes were analyzed by image analysis software to determine the area of cornea covered by new vessels as a percentage of the total corneal area. RESULTS: No ocular or systemic adverse events were observed. No change in visual acuity was noted in any patient following the injection. The mean change in corneal vascularization after one bevacizumab injection was 0.03%+/-0.45, while after two injections the change was 0.025%+/-0.19 (both not statistically different than zero, t-test). CONCLUSIONS: Short-term results suggest that subconjunctival bevacizumab is well tolerated but does not cause regression of corneal vessels in recurrent pterygium.     

贝伐单抗抑制角膜新生血管的实验研究

目的评价贝伐单抗（avastin）局部应用对小鼠角膜新生血管（CNV）的抑制作用。方法通过碱烧伤建立CNV模型,将30只Balb／c小鼠随机分成5组,A组贝伐单抗1mg／mL每日点眼2次;B组贝伐单抗3mg／mL每日点眼2次;C组贝伐单抗5mg／mL每日点眼2次;D组0．1％地塞米松每日点眼2次;E组生理盐水每日点眼2次。分别于术后3、7、14d观察CNV情况并拍照。术后第14天,处死全部小鼠,行CNV内皮细胞荧光标记,计算CNV所占全角膜面积的比例。结果各组CNV面积为A组（37．11±3．17）％、B组（29．75±3．56）％、C组（18．76±2．55）％、D组（20．91±2．75）％,E组（41．65±2．11）％。各组小鼠CNV面积依次为c组〈D组〈B组〈A组〈E组,C组同A、B、E组比较差异均有统计学意义（P〈0．01）,c组与D组比较差异无统计学意义（P=0．694）。结论局部应用贝伐单抗对小鼠角膜化学烧伤后的CNV有抑制作用。     

Effect of bevacizumab on corneal neovascularization in experimental rabbit model

Purpose:  To investigate the effect of bevacizumab in an experimental rabbit model of corneal neovascularization.
Methods:  The right eyes of 24 white New Zealand rabbits were included in a corneal neovascularization model using alkaline burn. They were divided into four groups. Topical bevacizumab was installed three times daily in group 1, 5 mg bevacizumab subconjunctivally every 2 days in group 2, 10 mg bevacizumab subconjunctivally every 2 days in group 3 and 0.2 cc of normal saline in the same way in group 4 (control group). All eyes were treated for 7 days. Then the animals were killed and corneal specimens sent for histopathological analysis. Tear film and aqueous humour samples were obtained to assess vascular endothelial growth factor (VEGF) levels.
Results:  Seven days after topical bevacizumab treatment the neovascular index in group 1 was lower than that in the control group ( P  = 0.028). In groups 2 and 3 the neovascular index was lower 2 days after subconjunctival bevacizumab treatment than that in control group ( P  = 0.009 and P  = 0.009, respectively). In the control group the VEGF level in aqueous humour increased by 66% from day 7 to 14. In groups 1–3 it decreased by 49.80%, 70.20% and 76.44%, respectively ( P  = 0.043). The VEGF level in tear film of the control group increased by 35.23% from day 7 to 14, which was not significant ( P  = 0.893), while in groups 1–3 it decreased by 57.26%, 34.59% and 67.97%, respectively, which was only significant in groups 1 and 3 ( P  = 0.043).
Conclusions:  Subconjunctival 5 mg/mL bevacizumab is effective in reducing corneal neovascularization in animal models and in reducing VEGF levels. Further research is needed to assess the potential side effects and minimal effective dose.     

贝伐单抗眼液对兔眼角膜新生血管抑制作用的实验研究

目的 探讨贝伐单抗(Avastin)滴眼液对兔眼碱烧伤或缝线诱导角膜新生血管的抑制作用.方法 54只家兔分别以碱烧伤法(27只)和缝线法(27只)诱导角膜新生血管模型,根据治疗方法不同随机再分为3组:Avastin眼液组、复方硫酸新霉素眼液组和生理盐水组.各组均于诱导后第7天给予相应药物滴眼,4次·d-1,共14 d.造模后第7天、第21天、第28天、第56天计算角膜新生血管面积,免疫组织化学法检测角膜组织中VEGF蛋白表达,RT-PCR法检测角膜组织中VEGF mRNA表达,酶联免疫吸附测定法(ELISA)检测房水内VEGF蛋白表达.结果 碱烧伤后第21天、第28天、第56天Avastin眼液组和复方硫酸新霉素眼液组角膜新生血管面积明显较生理盐水组短而稀疏,其中3个不同时间点Avastin眼液组的角膜新生血管面积分别为(26.16±7.02)mm2、(29.71±10.43)mm2、(26.10±10.72)mm2,均明显小于生理盐水组,差异均有统计学意义(均为P＜0.01);缝线后第21天、第28天、第56天时Avastin眼液组新生血管面积分别为(18.26±3.88)mm2、(37.24±3.16)mm2、(40.16±3.38)mm2,均明显小于复方硫酸新霉素眼液组和生理盐水组,差异均有统计学意义(均为P＜0.01);碱烧伤或缝线诱导后第21天,免疫组织化学结果显示Avastin眼液组角膜上皮层VEGF蛋白表达较生理盐水组均减弱,基质层新生血管较少;RT-PCR显示造模后第21天和第28天时,Avastin眼液组兔角膜组织内VEGF mRNA的表达均明显低于生理盐水组,差异均有统计学意义(均为P＜0.01),而造模后第56天时,Avastin眼液组和复方硫酸新霉素眼液组VEGF mRNA的表达均较生理盐水组高,差异均有统计学意义(均为P＜0.05);ELISA结果显示Avastin眼液组在碱烧伤和缝线诱导后第21天,房水VEGF蛋白含量分别为(81.0±8.7)ng·L-1、(110.0±9.0)ng·L-1,均明显低于复方硫酸新霉素眼液组和生理盐水组,差异均有统计学意义(均为P＜0.01).结论 Avastin滴眼液能有效地抑制兔眼碱烧伤后和缝线后角膜新生血管的生长,但在停药后1周缝线诱导的角膜新生血管较用药前明显增加,提示不同刺激因素引起的角膜新生血管用药时间应不同.     

Inhibitory effects of bevacizumab on angiogenesis and corneal neovascularization

Background

To evaluate the inhibitory effects of bevacizumab (Avastin®) on angiogenesis using cultured human umbilical vein endothelial cells (HUVECs) in vitro and on corneal neovascularization by subconjunctival injection of bevacizumab in vivo.

Methods

After the HUVECs were exposed to different concentrations of bevacizumab stimulated with VEGF (10 ng/ml) for 2, 6, and 24 hours, cellular-activity-like proliferation, migration and tube formation were assessed. Subconjunctival injection of bevacizumab (2.5 mg/0.1 ml) was performed after corneal chemical burn injury. Then the cornea was evaluated by biomicroscopy, fluorescein angiography, and light microscopy.

Results

The inhibitory effects of bevacizumab on VEGF-induced HUVECs proliferation showed a dose-dependent response for 2 and 6 hours, but all groups were effectively inhibited regardless of the concentration of bevacizumab for 24 hours. The inhibitory effects of bevacizumab on the migration of VEGF-induced HUVECs showed a time- and dose-dependent response. The inhibitory effects of bevacizumab on VEGF-induced HUVECs tube formation showed a dose-dependent response only for 24 hours. On days 3 and 8 after the subconjunctival injection, bevacizumab-treated eyes showed less neovascular growth than BSS-treated eyes in biomicroscopic, fluorescein angiographic, and light microscopic findings in vivo.

Conclusions

Bevacizumab effectively inhibits angiogenesis and corneal neovascularization, and could be used as a inhibitor of corneal neovascularization in the future.

     

贝伐单抗抑制角膜移植术后新生血管及免疫排斥反应的作用

目的 探讨贝伐单抗对同种异体角膜移植术后免疫排斥反应的影响,评价其对角膜植片存活的疗效及作用机制。设计 实验研究。研究对象 近交系F344大鼠15只为供体,近交系Lewis大鼠30只为受体。方法 受体大鼠右眼行穿透性角膜移植术后随机数字法分为3组：对照组（A组）、贝伐单抗组（B组）、地塞米松组（C组）,每组10只。B、C组分别于术后0、3、6、9天结膜下注射40 μl贝伐单抗注射液及20 μl地塞米松磷酸钠注射液;A组不做处理。术后裂隙灯下观察14天,记录排斥指数（RI,为植片水肿、混浊、新生血管长入评分合计）和新生血管侵袭面积（IA）。术后14天,采用免疫荧光法检测角膜植片中CD4+、CD8+免疫细胞的表达。主要指标 角膜新生血管面积,免疫排斥时间,免疫细胞的数量。结果 术后7天IA分别为：A组（22.50±3.67）mm2,B组（14.21±2.79）mm2,C组（15.38±0.84）mm2;A组明显多于B组及C组（P=0.00和0.01）,B组与C组无显著差异（P=0.059）。术后14天IA分别为：A组（27.96±0.50）mm2,B组（18.76±2.73）mm2,C组（23.74±2.14）mm2。A组及C组多于B组（P=0.000）。免疫排斥时间A组8天,B组11天,C组13天。B组及C组角膜植片存活时间均长于A组（P均=0.000）。免疫细胞： CD4+阳性细胞数：A组（13.2±2.94）个,B组（6.14±1.07）个,C组（3.5±1.78）个;CD8+阳性细胞数：A组（14.4±2.44）个,B组（4.5±1.51）个,C组（3.38±1.68）个。术后14天,B组、C组角膜植片中CD4+、CD8+细胞亦明显少于A组（P均=0.000）。结论 结膜下注射贝伐单抗可有效抑制大鼠同种异体穿透性角膜移植术后新生血管的生长,并可能通过此作用延缓移植排斥反应,延长角膜植片存活时间。但贝伐单抗抗移植排斥反应疗效略逊于地塞米松。（眼科,2017, 26： 101-105）     

Inhibition of corneal neovascularization by subconjunctival bevacizumab in an animal model

PURPOSE: To evaluate the effect of subconjunctival injection of bevacizumab on experimentally induced corneal neovascularization. DESIGN: Experimental animal study. METHODS: Twelve New Zealand white rabbits were involved, divided equally into four groups. Only one eye per rabbit was used. Topical instillation of 10 microl 5% NaOH solution was used, under general anesthesia, to induce corneal neovascularization secondary to corneal alkali burn in groups 2, 3, and 4. A single dose of 3.75 mg (25 mg/ml) bevacizumab was injected subconjunctivally. Group 1 (control group 1) was neither cauterized nor treated. Group 2 (control group 2) received a sham injection of balanced salt solution on day 14. Group 3 was treated on day 14 (after corneal neovascularization had been established). Group 4 was treated on day 1. Digital photographs were obtained and analyzed during the entire 28-day procedure. The area of neovascularization and scarring were measured in terms of the percentage of corneal surface affected. RESULTS: On day 28, the difference of neovascularization between groups 2, 3, and 4 was found to be statistically significant at the .05 level (one-way analysis of variance [ANOVA]): group 4 (4.7%+/-3.1%).1, one-way ANOVA). No side effects were noted. CONCLUSIONS: Subconjunctival administration of bevacizumab inhibits corneal neovascularization effectively in the rabbit experimental model, especially if administered early.     

Therapeutic effect of subconjunctival injection of bevacizumab in the treatment of corneal neovascularization

Purpose: To investigate the efficacy of subconjunctival injection of bevacizumab in the treatment of patients with corneal neovascularization. Methods: Twenty‐nine eyes of 29 patients with corneal neovascularization were treated with subconjunctival injection [1.25 mg/0.05 ml (seven eyes), 2.5 mg/0.1 ml (15 eyes) and 5.0 mg/0.2 ml (seven eyes)] of bevacizumab. Best‐corrected visual acuity, intraocular pressure and area of corneal neovascularization were measured before injection and at 1 week, 1 month and 3 months after treatment. Results: At 1 week, the mean neovascularized corneal area decreased significantly to 85.5 ± 18.0% (p = 0.01) in the eyes treated with 2.5 mg bevacizumab and to 73.1 ± 23.4% (p = 0.02) in the eyes treated with 5.0 mg bevacizumab. At 3 months, the mean neovascularized corneal area was 93.6 ± 10.6% (p = 0.10 compared to baseline; p < 0.01 compared to 1 week) in the eyes treated with 2.5 mg bevacizumab and 83.3 ± 25.8% (p = 0.03 compared to baseline; p = 0.02 compared to 1 week) in the eyes treated with 5.0 mg bevacizumab. However, there were no significant changes in the areas of the eyes injected with 1.25 mg bevacizumab. Conclusion: Subconjunctival injection of bevacizumab can partially reduce corneal neovascularization in the short term, and the efficacy of this treatment correlates with the injection dose.