Intravascular site-specific delivery of a therapeutic antisense for the inhibition of restenosis

Background: Polymeric nanoparticles (NPs) have been implicated as potential gene carriers in the treatment of various genetic and acquired diseases. In this work we investigated the efficacy of NPs as gene carrier for intravascular gene therapy in animal models of restenosis. Methods: A therapeutic antisense against the monocyte chemotactic protein-1 (anti-MCP-1) was encapsulated into the poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) using double-emulsion/solvent evaporation technology. Laser defractometer was used to assess size distribution of NPs. Particle morphology was assessed by scanning electron microscopy (SEM). DNA content in NPs was determined by DNA extraction using TE buffer from a chloroform solution dissolved a known amount of NPs. DNA concentration was assayed by spectrophotometer. in vitro DNA release was performed in the TE buffer at 37 degrees C utilizing double-chamber diffusion cell. NPs loaded with pEGFP and anti-MCP-1 gene were tested in SMC cell culture for transduction efficiency. The anti-MCP-1 NPs were further evaluated in rabbit vein grafting and carotid artery injury models for their potential in inhibition of restenosis. Results: The NPs demonstrated a steady in vitro release of DNA with approximately 95% of total enclosed DNA released within 30 days. Anti-sense MCP-1 expression was confirmed in arterial tissues with single infusion of the therapeutic NPs into the injured rabbit carotid arteries. The intima/media ratio of arteries treated with the anti-MCP-1 NP was reduced by 43% compared with control groups following a 2-week treatment. In a rabbit jugular vein-to-artery-bypass grafting model, animals with local-infusion of anti-MCP-1 NPs also demonstrated a significantly lower intimal hyperplasia than that of control groups with no or free antisense treatment. Conclusion: Collectively, our data revealed that local delivered anti-MCP-1 NPs effectively inhibited experimental restenosis. (C) 2008 Elsevier B.V. All rights reserved.