Effect of subconjunctival bevacizumab (Avastin) on experimental corneal neovascularization in guinea pigs

PURPOSE: To evaluate the effect of subconjunctival bevacizumab (Avastin) on experimental corneal neovascularization in guinea pigs. METHODS: Forty eyes of 40 guinea pigs were chemically cauterized with 75% silver nitrate and 25% potassium nitrate sticks. Fifteen eyes (group 1) received 2 subconjunctival injections of bevacizumab (0.1 mL, 1.25 mg) simultaneously with cauterization and 3 days later. Fifteen eyes (group 2) received 2 subconjunctival injections of bevacizumab (0.1 mL, 1.25 mg) 3 and 5 days after cauterization. Ten eyes (group 3, control group) received 2 subconjunctival injections of 0.1 mL of balanced salt solution 3 and 5 days after cauterization. After we determined the burn and neovascularization scores for all groups, the animals were killed on the 10th day. The percentages of neovascularization on the surface of the cornea were measured in terms of pixels on digital photographs. The average number of vessels at maximally vascularized areas was determined for each specimen. RESULTS: Neovascularization score was 1.1 +/- 0.3 in group 1, 2.46 +/- 1.3 in group 2, and 3.5 +/- 0.5 in the control group. The difference was statistically significant (P < 0.001). The area of neovascularization at the cornea surface was 15.6% +/- 10.1% in group 1, 19.74% +/- 11.2% in group 2, and 23.5% +/- 7.4% in the control group (P = 0.194). The average number of neovascular vessels at group 1 was significantly reduced in comparison with group 2 and the control group (P < 0.001). CONCLUSIONS: Subconjunctival injection of bevacizumab decreases the extent of chemically induced corneal neovascularization in guinea pigs. The antineovascular effect of bevacizumab is higher if the injection is performed simultaneously with the chemical cauterization.     

结膜下注射贝伐单抗对兔角膜新生血管的抑制作用

目的 观察碱烧伤后不同时间结膜下注射贝伐单抗（Bevacizumab）角膜新生血管（CNV）的形成与转归.方法 新西兰白兔54只,制成单眼碱烧伤模型,随机分为3组,每组18只眼,A组碱烧伤后结膜下立即注射贝伐单抗2.5 mg（0.1 ml）,B组碱烧伤后3d结膜下注射贝伐单抗2.5 mg（0.1 ml）,C组结膜下注射生理盐水0.1ml,为对照组.共观察28 d.裂隙灯显微镜下观察角膜新生血管生长情况,行眼前段照相并计算其面积,伤后7、14、28 d各组随机取6例角膜行共焦显微镜检查,观察角膜组织炎性细胞浸润情况及角膜新生血管形态学变化.结果 A、B及C组角膜新生血管开始出现的时间分别为（5.9＋0.8）d、（3.5＋0.6）d及（3.4＋1.1）d,其中A组明显较C组延长（P＜0.05）,B组与C组差异无统计学意义（P =0.068）.伤后各时间点A、B组角膜新生血管的生长面积均明显较C组减少（P＜0.05）,A组与B组角膜新生血管面积比较,差异有统计学意义（P＜0.05）.共焦显微镜检查可见C组烧伤区大量炎性细胞浸润及新生血管形成,而A组角膜炎性细胞较少,烧伤区无新生血管形成,B组见少量新生血管侵入烧伤区.3组基质层均可见纤维及瘢痕组织增生,其中治疗组纤维增生程度与瘢痕组织均较对照组轻.结论 结膜下注射贝伐单抗可抑制角膜炎性细胞形成,改善损伤角膜基质,促进角膜愈合,从而减少碱烧伤引起的角膜新生血管的生长,在早期注射能取得更好的疗效.     

Bevacizumab inhibits corneal neovascularization in an alkali burn induced model of corneal angiogenesis

BACKGROUND: New and uncontrolled blood vessel development in the cornea is a pivotal process in the pathogenesis of several corneal diseases. These corneal diseases may finally cause blindness and managing them therapeutically is problematic. The data supporting a causal role for vascular endothelial growth factor in corneal neovascularization are extensive. This study aimed to evaluate the effect of subconjunctival bevacizumab (Avastin) on experimental corneal neovascularization in rabbits. METHODS: Chemical cauterization of the cornea was performed by touching central cornea with a 5-mm-diameter NaOH-soaked cotton applicator for 10 s in 20 eyes of 20 White New Zealand rabbits. The rabbits were then divided randomly into two equal groups. Bevacizumab (2.5 mg) was administered to 10 eyes (group 1) by a subconjunctival injection immediately after chemical cauterization of corneal surface. As a control, 10 eyes (group 2) received an injection of distilled water. Rabbits were examined daily for detection of the first signs of neovascularization. Three weeks later, the extent of corneal neovascularization was evaluated by direct examination and photograph analyses. Total corneal neovascularization area, degree of circumference involved and longest neovascular pedicle length were assessed. RESULTS: Bevacizumab significantly decreased the total neovascularization area (P < 0.009), the circumference involved (P < 0.011) and the longest neovascular pedicle length (P < 0.023). CONCLUSION: Local injection of bevacizumab has a significant effect on inhibition of alkali burn-induced corneal neovascularization. This shows the potential value of bevacizumab in the treatment of corneal neovascularization.     

结膜下注射Avastin抑制角膜新生血管的实验研究

目的:观察结膜下注射Avastin对实验性兔眼角膜新生血管(neovascularization,NV)的抑制作用,初步探讨作用机制。方法:应用5mm直径的加样器(末端附有棉片)吸入1mol/LNaOH接触新西兰兔右眼(20眼)中央角膜区烧灼30s,制作碱烧伤兔眼角膜NV模型。将实验兔随机分成2组,10眼(A组)碱烧伤后立即结膜下注射Avastin 2.5mg;其余10眼为对照组(B组),结膜下注射等量生理盐水。烧灼后次日每天裂隙灯观察角膜NV、角膜水肿情况,分别于3,7,14,21,28d裂隙灯照相并计算NV面积及NV抑制率。伤后7,28d各组随即处死5只实验兔,取角膜组织做石蜡切片行组织病理学检查及VEGF免疫组织化学检测。结果:两组兔眼伤后第1d角膜缘血管网明显扩张充血,3d时血管开始侵入角膜,7～14d时NV达到高峰,14～21d后NV稳定并逐渐回退。两组角膜NV长度、NV面积及角膜水肿程度存在差异(P<0.05);A组各时间点角膜NV抑制率为44.2%～55%。A组角膜上皮及实质层水肿较轻,NV较少,后弹力层基本完整,VEGF表达明显弱于B组。结论:结膜下注射Avastin对碱烧伤诱导的兔眼角膜NV形成及生长具有明显的抑制作用,可能通过下调VEGF表达发挥作用。     

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.     

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

AIM: To investigate the effects of bevacizumab and ranibizumab on corneal neovascularization in an alkali burn-induced model of corneal angiogenesis. METHODS: 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. RESULTS: 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. CONCLUSION: 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.     

Inhibition of experimental corneal neovascularisation by bevacizumab (Avastin)

AIM: To evaluate the effect of topically administered bevacizumab (Avastin) on experimental corneal neovascularisation in rats. METHODS: Silver nitrate sticks (75% silver nitrate, 25% potassium nitrate) were used to perform chemical cauterisation on the corneas of 16 eyes from 16 male Long Evans rats. For the following 7 days, the 10 eyes in the treatment group were instilled with bevacizumab 4 mg/ml drops twice daily, whereas the 6 eyes in the control group received placebo (normal saline drops twice daily). Digital photographs of the cornea were analysed to determine the area of cornea covered by neovascularisation as a percentage of the total corneal area. RESULTS: In the bevacizumab-treated eyes, neovascularisation covered, on average, 38.2% (15.5%) (mean (SD)) of the corneal surface compared with 63.5% (5.0%) in the control group (p<0.02, Mann-Whitney U test). CONCLUSION: Topically administered bevacizumab (Avastin) at a concentration of 4 mg/ml limits corneal neovascularisation following chemical injury in the male Long Evans rat model.     

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.

     

金雀异黄素对兔角膜碱烧伤新生血管的抑制作用

目的:探讨金雀异黄素(genistein,Gen)对兔角膜新生血管(corneal neovascularization,CNV)的抑制作用。方法:取新西兰大白兔13只,不造模1只观察药物对眼表前房等组织的不良反应。其余12只24眼采用浸润1mol/LNaOH滤纸片贴敷角膜中心60s,诱导碱烧伤CNV形成,左眼用二甲亚砜(dimethylsulfoxide,DMSO)溶液,右眼用Gen的DMSO溶液点眼。碱烧伤后3,7,14,21d测量角膜CNV面积,处死相应组别的动物取眼球做切片HE染色和免疫组织化学染色观察角膜和前房等情况。结果:兔角膜碱烧伤后CNV存在生长和消退的病理变化,Gen+DMSO组角膜CNV面积与DMSO组相比有明显的统计学差异性(P<0.01)。结论:Gen对于兔角膜碱烧伤模型的CNV有明显的抑制作用。     

The effect of different doses of subconjunctival bevacizumab injection on corneal neovascularization

To evaluate the effects of various doses of subconjunctival bevacizumab injections in the treatment of patients with corneal neovascularization. During the 6-month-follow-up, no significant ocular or systemic adverse events were observed related to the subconjunctival bevacizumab injection. In Group 1, the total area of corneal neovascularization before injection was 14.8 ± 3.2 % of the corneal surface and 10.2 ± 2.8 % 6 months after injection (p < 0.01). The mean decrease in Group 1 was 32.0 ± 3.0 %. In Group 2, the total area of corneal neovascularization before and 6 months after the injection was 14.2 ± 2.5 and 9.8 ± 2.3 %, respectively (p < 0.01). The mean decrease in Group 2 was 31.0 ± 2.3 %. The difference between the two groups was not statistically significant (p > 0.05). Twenty-four eyes of 24 patients with corneal neovascularization who were treated with a subconjunctival injection of bevacizumab were included in this retrospective study. Fourteen eyes were treated with 2.5 mg/0.1 ml (Group 1), and 10 eyes were treated with 5.0 mg/0.2 ml (Group 2) of subconjunctival bevacizumab. Digital photographs of the cornea were used to determine the area of corneal neovascularization before injection and at 1 month, 3 months, and 6 months after treatment. Subconjunctival injection of bevacizumab is well tolerated and associated with a partial regression of corneal neovascularization. The efficacy of this treatment is not correlated to the injection dose.     

Avastin对大鼠角膜新生血管的抑制及超微结构的影响

目的:探讨Avastin对角膜新生血管形成及角膜内血管内皮生长因子(VEGF)的影响及其超微结构的影响。方法:Wistar大鼠96只随机分3组,采用碱烧伤的方法制备大鼠角膜新生血管模型;正常不烧伤组4只。烧伤后隔日球结膜下注射0.1mL生理盐水组32只,烧伤后隔日球结膜下注射Avastin0.1mL组32只,烧伤后隔日球结膜下注射地塞米松0.1mL组32只。碱烧伤术后在裂隙灯显微镜下观察大鼠角膜混浊度;宏观测量新生血管长度;组织病理切片HE染色作微血管计数;透射电镜观察超微结构的改变;免疫组化检测角膜VEGF的蛋白表达情况;CD34标记新生血管,显微镜下微血管计数方法研究角膜新生血管形成及抑制情况。结果:治疗组在3,7,10,14d较对照组角膜混浊程度轻(P<0.05);14d形成的新生血管数量较对照组少(P<0.05)。实验组新生血管微血管数量减少,VEGF蛋白表达下降,具有统计学差异。VEGF主要表达在角膜受损区的感染细胞胞质内,其出现时间与位置与角膜新生血管一致。Avastin和地塞米松均可有效抑制角膜新生血管,减少角膜内VEGF表达,两者无统计学差异,结膜下注射Avastin和地塞米松后,大鼠角膜超微结构无除烧伤后其它显著改变。结论:Avastin和地塞米松可抑制角膜新生血管,减少角膜内VEGF表达,对角膜的超微结构均无显著毒性。     

Anti-VEGF monoclonal antibody-induced regression of corneal neovascularization and inflammation in a rabbit model of herpetic stromal keratitis

Background

To determine the efficacy of bevacizumab (Avastin), an anti-VEGF monoclonal antibody, administrated via subconjunctival injection as a corneal anti-angiogenic treatment.

Methods

Right corneas of rabbits were infected with herpes simplex virus type 1, KOS strain. On day 13 post-infection (p.i.), animals were treated subconjunctivally (sc) with a single 10-μl dose (25 μg/μl) of bevacizumab (group A) or with the same volume of an isotype monoclonal antibody, as negative control (group B). All animals were observed clinically on days 2, 5, 7, 14, 21, and 28 p.i., and two corneas each day were obtained for histological assessment and viral titration.

Results

Viral replication was observed no longer than 5 days after infection. By day 7 a dense neutrophil invasion of the cornea was detected, which significantly increased while herpetic stromal keratitis progressed in severity. Positive outcomes observed following the treatment with bevacizumab, compared to control, included: (1) Total involution of neovascularization, (2) reduction in disease severity, (3) improved corneal translucency, (4) absence of scarring, (5) preservation of corneal thickness, (6) no neutrophil infiltration of the cornea.

Conclusions

Subconjunctival administration of bevacizumab induced involution of new vessels, abolished inflammatory response, and resulted in return of corneal function. Furthermore, bevacizumab is a novel approach for the treatment of herpetic stromal keratitis.     

Inhibitory effect of triamcinolone acetonide on corneal neovascularization

Background Corneal neovascularization (NV) plays an important role in the pathogenesis of corneal disorders. Recently, triamcinolone acetonide (TA) has been reported as a potential treatment for ocular angiogenesis. However, there are no reports on the inhibitory effect of TA on the corneal NV. Methods Triamcinolone acetonide (2 mg) was administered to four rabbits' eyes by a subconjunctival injection immediately after a basic fibroblast growth factor (bFGF)-pellet was placed into the cornea. As a control, four eyes received an injection of distilled water. Four weeks later, the inhibition of corneal NV was evaluated as the percentage ratio of the vessel invasion area to the area that was sandwiched between the pellet and the limbus cornea. To identify the characteristic appearance of new corneal vessels, the control cornea was examined by using the antibody of vascular endothelial growth factor (VEGF). To confirm TA concentration in TA-treated corneas, the TA level was measured using high-performance liquid chromatography. Results Neovascularization from the limbus to the pellet was detected in control eyes 4 weeks after the bFGF pellet implantation. TA-treated eyes demonstrated the inhibition of the neovascular response to the pellet. The severity of NV as compared between control and TA-treated eyes was statistically significant (P<0.05). Morphologically, new vessel growth was shown in the control cornea, and endothelial cells of new vessels were positively stained with the antibody of VEGF. TA concentration in TA-treated corneas at 2 weeks showed 63.5±42.8 μg/g (n=4, mean ± SD), while TA was not detected in control and TA-treated corneas at 4 weeks. The level of TA was effectively maintained for at least 2 weeks after the subconjunctival injection. Conclusion We have demonstrated that subconjunctival TA administration inhibited rabbit corneal NV. This agent may prove useful in the treatment of corneal angiogenic disorders. No human subjects are involved as experimental animals were used in this study     

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.     

Short- and long-term safety profile and efficacy of topical bevacizumab (Avastin®) eye drops against corneal neovascularization

Purpose

To evaluate the short- and long-term in vivo safety and efficacy of topical bevacizumab (Avastin) application for treatment of corneal neovascularization secondary to a variety of corneal diseases.

Methods

Thirty eyes of 27 patients with progressive corneal neovascularisation (not responding to conventional anti-inflammatory treatment) due to different underlying corneal diseases received topical bevacizumab (Avastin) eye drops (5 mg/ml Bevacizumab) for 0.5–12 months (five times/day on average). At each visit, a routine Snellen visual acuity assessment was performed, followed by ophthalmic examination including fluorescein staining. Changes of corneal neovascularization and vessel diameter were assessed using morphometry of standardized digital corneal photographs.

Results

Five patients (five eyes) developed new corneal epithelial defects during topical bevacizumab treatment. In 22 patients, no new epithelial defects were observed. None of the 27 patients complained about any drug-related ocular or systemic adverse events during follow-up. No allergic reactions were observed. Corneal photographs of 21 eyes (19 patients) could be assessed. The mean reduction in vascularized area during treatment was 61%. The mean reduction in vessel diameter under topical Avastin therapy was 24%.

Conclusions

Off-label topical bevacizumab therapy against corneal neovascularization secondary to different corneal diseases was generally well-tolerated for up to 12 months. Bevacizumab (Avastin) eye drops inhibit corneal neovascularization, and lead to a reduction of the vessel diameter. Our results suggest that off-label use of Bevacizumab eye drops is a relatively safe and well-tolerated option for the treatment of corneal neovascularization. Care should be taken in patients with epithelial defects and neurotrophic keratopathy.     

The Effect of Bevacizumab on Corneal Neovascularization in Rabbits

Purpose

To determine the efficacy of topical application and subconjunctival injection of bevacizumab in the treatment of corneal neovascularization.

Methods

Corneal neovascularization was induced with a silk suture of the corneal stroma in 12 rabbits (24 eyes). One week after suturing, four rabbits were treated with topical bevacizumab at 5 mg/mL (group A) and another four rabbits were treated with topical bevacizumab 10 mg/mL (group B) in the right eyes twice a day for two weeks. A subconjunctival injection of bevacizumab 1.25 mg/mL was done in the right eyes of four rabbits (group C). All of the left eyes (12 eyes) were used as controls. The area of corneal neovascularization was measured after one and two weeks, and the concentration of vascular endothelial growth factor (VEGF) in corneal tissue was measured after two weeks.

Results

The neovascularized area was smaller in all treated groups than in the control group (p<0.001). Upon analysis of the neovascularized area, there was no significant difference between groups A and B. However, the mean neovascularized area of group B was significantly smaller than that of group C after two weeks of treatment (p=0.043). The histologic examination revealed fewer new corneal vessels in all treated groups than the control group. The concentration of VEGF was significantly lower in all treated groups compared to the control group (p<0.01), but no difference was shown between treated groups.

Conclusions

Topical and subconjunctival bevacizumab application may be useful in the treatment of corneal neovascularization and further study is necessary.     

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.     

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.     

Suppression of retinal neovascularization by the iNOS inhibitor aminoguanidine in mice of oxygen-induced retinopathy

Background  Retinal neovascularization (NV) is a major cause of blindness associated with ischemic retinal disorders. Our study was focused on evaluating the inhibitory effect of aminoguanidine (AG), an inhibitor of inducible nitric oxide synthase (iNOS), on retinal NV in mice of oxygen-induced retinopathy (OIR). Methods  An OIR model was established with 7-day-old C57BL/6J mice. One day before and 1 and 3 days after being returned to the room air, the right eyes were injected intravitreally with bevacizumab, AG or bevacizumab+AG respectively. The left eyes were injected with normal saline (NS) as control. The mice were killed at postnatal day 17 (P17). The effects of AG or bevacizumab on iNOS or VEGF expressions were evaluated by RT-PCR and immunohistochemistry. Retinal NV was examined by fluorescein angiography, and was quantified histologically by CD34 immnunostaining at P17. Results  Compared with NS-treated eyes, retinal VEGF and iNOS mRNA expressions were significantly reduced in AG- and bevacizumab+AG-treated eyes; whereas in bevacizumab-treated eyes, retinal VEGF mRNA expression increased and iNOS mRNA expression remained unchanged. The above changes were confirmed by immunohistochemical study. The generalized decrease in both VEGF and iNOS distributions in mice retina treated with AG or bevacizumab+AG was demonstrated by immunohistochemistry. Retinal NV was significantly reduced in all three groups treated with bevacizumab, AG or bevacizumab+AG, when compared with NS-treated eyes. Conclusions  iNOS activation plays a pathological role in retinal NV in a mouse model of ischemic retinopathy. Administration of AG significantly suppressed retinal NV. Therefore, AG appears to be a novel and effective therapeutic approach for retinal NV. Ling Wang and Guo-Tong Xu are co-corresponding authors who contributed equally to this study.