Synthetic high-density lipoprotein nanoparticles delivering rapamycin for the treatment of age-related macular degeneration

Synthetic high-density lipoprotein (sHDL) and rapamycin (Rap) have both been shown to be potential treatments for age-related macular degeneration (AMD). The low aqueous solubility of Rap, however, limits its therapeutic utility. Here we used an Apolipoprotein A-I mimetic peptide and phospholipid-based sHDL for the intravitreal delivery of Rap. By incorporation of Rap in sHDL nanoparticles (sHDL-Rap), we achieve 125-fold increase in drug aqueous concentration. When applied in vitro to retinal pigment epithelium cells, sHDL-Rap exhibited the abilities to efflux cholesterol, neutralize endotoxin, and suppress NF-κB activation. As an mTOR inhibitor, Rap induced autophagy and inhibited NF-κB-mediated pro-inflammatory signaling. Additionally, a greater reduction in lipofuscin accumulation and increased anti-inflammatory effects were achieved by sHDL-Rap relative to free drug or sHDL alone. In vivo studies demonstrated that sHDL reached the target retina pigment epithelium (RPE) layer following intravitreal administration in rats. These results suggest that sHDL-Rap holds potential as a treatment for AMD.