Sustained-Release Microspheres of Rivoceranib for the Treatment of Subfoveal Choroidal Neovascularization.

The wet type of age-related macular degeneration (AMD) accompanies the subfoveal choroidal neovascularization (CNV) caused by the abnormal extension or remodeling of blood vessels to the macula and retinal pigment epithelium (RPE). Vascular endothelial growth factor (VEGF) is known to play a crucial role in the pathogenesis of the disease. In this study, we tried to repurpose an investigational anticancer drug, rivoceranib, which is a selective inhibitor of VEGF receptor-2 (VEGFR2), and evaluate the therapeutic potential of the drug for the treatment of wet-type AMD in a laser-induced CNV mouse model using microsphere-based sustained drug release formulations. The PLGA-based rivoceranib microsphere can carry out a sustained delivery of rivoceranib for 50 days. When administered intravitreally, the sustained microsphere formulation of rivoceranib effectively inhibited the formation of subfoveal neovascular lesions in mice.

Effective systemic siRNA delivery using dual-layer protected long-circulating nanohydrogel containing an inorganic core.

Systemic delivery of small interfering RNA (siRNA) has been mainly impeded by enzymatic degradation and poor cellular uptake. Calcium phosphate (CaP) has been considered a potential candidate for siRNA delivery because of its excellent biocompatibility and capability of entrapping siRNA in the crystal core. Based on the property of 3,4-dihydroxy-l-phenylalanine (dopa) binding to the surface of the CaP crystal, dual hydrogel layers consisting of a macromolecular dextran (dex) and polyethylene glycol (PEG) were introduced on the surface of the inorganic CaP core for prolonged circulation. Dextran conjugated with dopa and polyethylene glycol (PEG) (PEG-dex-dopa) can effectively control the overgrowth of the CaP/siRNA core and stabilize it by dual electrically neutral hydrophilic layers of dextran and PEG, which additionally provide reduced hepatic accumulation and systemic clearance. The dual shield of PEG-dex-dopa nanohydrogel containing a CaP/siRNA core (PEG-dex-dopa/CaP/siRNA) significantly improved the pharmacokinetic behaviors of siRNA after systemic administration, resulting in its increased distribution to tumors and the effective inhibition of tumor growth by silencing vascular endothelial growth factor (VEGF) gene expression through the enhanced permeability and retention (EPR) effect.

Enhanced Transfection of Human Mesenchymal Stem Cells Using a Hyaluronic Acid/Calcium Phosphate Hybrid Gene Delivery System.

Human mesenchymal stem cells (hMSCs) show enormous potential in regenerative medicine and tissue engineering. However, current use of hMSCs in clinics is still limited because there is no appropriate way to control their behavior in vivo, such as differentiation to a desired cell type. Genetic modification may provide an opportunity to control the cells in an active manner. One of the major hurdles for genetic manipulation of hMSCs is the lack of an efficient and safe gene delivery system. Herein, biocompatible calcium phosphate (CaP)-based nanoparticles stabilized with a catechol-derivatized hyaluronic acid (dopa-HA) conjugate were used as a carrier for gene transfection to hMSCs for improved differentiation. Owing to the specific interactions between HA and CD44 of bone marrow-derived hMSCs, dopa-HA/CaP showed significantly higher transfection in hMSCs than branched polyethylenimine (bPEI, MW 25 kDa) with no cytotoxicity. The co-delivery of a plasmid DNA encoding bone morphogenetic protein 2 (BMP-2 pDNA) and micro RNA 148b (miRNA-148b) by dopa-HA/CaP achieved significantly improved osteogenic differentiation of hMSCs.