Strategic delivery of rapamycin and ranibizumab with intravitreal hydrogel depot disrupts multipathway-driven angiogenesis loop for boosted wAMD therapy

Abstract

Autophagic dysfunction-induced deterioration of the retinal microenvironment drives the progression of wet age-related macular degeneration (wAMD). The efficacy of single-target anti-VEGF antibodies in treating wAMD has long been suboptimal due to the intricate interplay between autophagy dysfunction, oxidative stress, and angiogenesis. Here, we introduce an intravitreal hydrogel depot, named Rab&Rapa-M@G, consisting of rapamycin-loaded microemulsion (Rapa-M, an mTOR inhibitor), ranibizumab (anti-VEGF antibody), and a thermosensitive hydrogel matrix. A single intravitreal injection of Rab&Rapa-M@G can sustainably deliver Rapa-M and ranibizumab to the retinal pigment epithelium for at least 14 days. This formulation significantly improves retinal autophagic flux homeostasis and reduces oxidative stress injury in wAMD mice by modulating the AMPK/mTOR/HIF-1α/VEGF and AMPK/ROS/HO-1/VEGF pathways. Consequently, it synergistically disrupts the “autophagic dysfunction-oxidative stress-angiogenesis” loop, leading to a remarkable reduction in choroidal neovascularization area and retinal damage compared to ranibizumab alone. Notably, the sequential administration of ranibizumab and Rab&Rapa-M@G further enhances the overall anti-wAMD efficacy, achieved through sequential delivery of Rab and Rapa, allowing for a more precise grasp of the treatment window. In conclusion, this hydrogel depot design, with its sequential and sustained delivery of mTOR inhibitors and anti-VEGF antibodies, offers a promising strategy for multi-target synergistic therapy in wAMD.