Delineating effects of angiopoietin-2 inhibition on vascular permeability and inflammation in models of retinal neovascularization and ischemia/reperfusion.

Introduction: Clinical trials demonstrated that co-targeting angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF-A) with faricimab controls anatomic outcomes and maintains vision improvements, with strong durability, through 2 years in patients with neovascular age-related macular degeneration and diabetic macular edema. The mechanism(s) underlying these findings is incompletely understood and the specific role that Ang-2 inhibition plays requires further investigation. Methods: We examined the effects of single and dual Ang-2/VEGF-A inhibition in diseased vasculatures of JR5558 mice with spontaneous choroidal neovascularization (CNV) and in mice with retinal ischemia/reperfusion (I/R) injuries. Results: In JR5558 mice, Ang-2, VEGF-A, and dual Ang-2/VEGF-A inhibition reduced CNV area after 1 week; only dual Ang-2/VEGF-A inhibition decreased neovascular leakage. Only Ang-2 and dual Ang-2/VEGF-A inhibition maintained reductions after 5 weeks. Dual Ang-2/VEGF-A inhibition reduced macrophage/microglia accumulation around lesions after 1 week. Both Ang-2 and dual Ang-2/VEGF-A inhibition reduced macrophage/microglia accumulation around lesions after 5 weeks. In the retinal I/R injury model, dual Ang-2/VEGF-A inhibition was statistically significantly more effective than Ang-2 or VEGF-A inhibition alone in preventing retinal vascular leakage and neurodegeneration. Discussion: These data highlight the role of Ang-2 in dual Ang-2/VEGF-A inhibition and indicate that dual inhibition has complementary anti-inflammatory and neuroprotective effects, suggesting a mechanism for the durability and efficacy of faricimab in clinical trials.

Optimized Subretinal Injection Technique for Gene Therapy Approaches.

Gene therapy for inherited eye diseases requires local viral vector delivery by intraocular injection. Since large animal models are lacking for most of these diseases, genetically modified mouse models are commonly used in preclinical proof-of-concept studies. However, because of the relatively small mouse eye, adverse effects of the subretinal delivery procedure itself may interfere with the therapeutic outcome. The method described here aims to provide the details relevant to perform a transscleral pars plana virus-mediated gene transfer to achieve an optimized therapeutic effect in the small mouse eye.

Advanced Ocular Injection Techniques for Therapy Approaches.

Treatment approaches for inherited eye diseases require local therapeutic molecule delivery by intraocular injection. One important factor that can influence the study outcome is the quality of intraocular administration. The intracompartmental structure (e.g., vitreous) of the eye allows a sustainable release of therapeutic biologicals using an intravitreal delivery. The protocol described here aims at providing the details relevant to perform a transscleral pars plana intravitreal transfer in small eyes using a genetically modified stem cell system. The fact that cells and therewith visually distinct particles are implanted, allows for the assessment of the implantation site and the distribution, and possibilities for temporal follow up studies-hence, valuable information becomes available which can be used to fine-tune the intravitreal delivery technique.