Laila Kudsiova, Alison Bienneman, Katharina Welser, Frederick Campbell, Stephen Hart, Helen C. Hailes, Alethea B. Tabor and M. Jayne Lawrence

Institute of Pharmaceutical Science, King's College London, UK

Abstract:

Gene therapy offers great promise for the treatment of dementias and other neurological disorders, however various obstacles such as overcoming the blood brain barrier and targeting the required cell population while achieving good vector distribution and transfection remain a major challenge. In this work the use of anionic versus cationic lipopolyplexes (formulated using DNA, anionic lipid bearing a short polyethylene glycol (PEG) chain to confer steric stability and a cationic bi-functional targeting peptide designed to condense the DNA and improve its cellular intrenalisation through targeted receptormediated endocytosis) was investigated upon convection enhanced delivery (CED) to the brain. CED is a technique used to inject the nanoparticles to a specific region of the brain under positive hydrostatic pressure. Since CED relies primarily on the generated pressure gradient rather than diffusion, a wider, more homogeneous distribution of the particles is achieved.

CED injections of fluorescently labelled lipopolyplexes into Wistar rat brain showed that up to 20x larger volumes of distribution were achieved using anionic lipopolyplexes compared to cationic lipopolyplexes after 4 hours of injection, however 48 hours later, the distribution pattern of both cationic and anionic lipopolyplexes was similar. More importantly the transfection efficiency, measured by pGFP expression, was higher in cationic formulations, indicating that cationic lipopolyplexes prepared using anionic lipid, cationic peptide and DNA are promising gene delivery vectors for the treatment of dementias upon CED.