Allosteric modulator of microtubule end-binding protein-3 blocks laser-induced choroidal neovascularization

Abstract

Purpose : Age-related macular degeneration is account for more than 54% of all vision loss in the USA. Although current anti-VEGF therapies are effective in delaying the progression of disease, they do not eliminate the risk of blindness. This study establishes therapeutic benefits of novel allosteric inhibitor of end-binding protein 3 (EBIN) in treatment of aberrant ocular neovascularization using an experimental model of laser-induced choroidal neovascularization (CNV).

Methods : C57/B6 male mice (6-8 week old; N=9 per group) were used for these studies. A new the Micron IV platform image-guided laser system was adapted for CNV induction. Four laser burns at equal distance from the optic nerve were induced in right eye by a Argon laser pulse with a λ=532 nm, duration of 70 ms, and power levels 210-250 mW. Treatment with control or EBIN peptides (1µg/eye), or antibody against mouse VEGF-A (2µg/eye; LEAF™) were administrated after the laser photocoagulation via intravitreal injection. Another cohort of mice was treated with eye drops EBIN (5µg per eye, twice daily) in combination with intravitreal injection of control or α-VEGF-A antibodies (2µg/eye). The post-mortem analysis of CNV area was performed using the flat mount preparations of retina/choroid/sclera stained with Alexa594-labled lectin from Bandeiraea simplicifolia. The area of CNV were quantified using fluorescein confocal images. One-way ANOVA and Tukey post hoc test was used for statistical analysis. Data are presented as mean±SD.

Results : CNV area were significantly decreased in both treatment groups, EBIN (p<0.001) and α-VEGF Ab (p<0.01), as compared to control group. Whereas CNV area reached 0.075±0.04 mm² in control group, CNV area were significantly smaller, 0.02±0.013 mm² and 0.04±0.025 mm², in EBIN and α-VEGF Ab groups, respectively. Furthermore, treatment with EBIN drops also decrease CNV area to 0.011±0.013 mm² (p<0.001) when EBIN treatment was combined with intravitreal injection of control antibody. However, combination of EBIN drops with anti-VEGF therapy did not provide any additional improvement. CNV area were 0.037±0.03 mm² and not different from CNV area observed for anti-VEGF treatment alone.

Conclusions : Treatment with EBIN significantly reduces the CNV. Our data suggest that EBIN may represent a novel strategy for treating aberrant ocular angiogenesis.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.