lipofectamine and Ischemia

A major problem when using cationic polymers for gene delivery is that transfection is strongly inhibited by the presence of serum. This shortcoming limits the application of cationic polymers for systematic gene delivery in vivo. Due to the shielding effect of heparin, heparin conjugation to cationic polymers may improve the in vivo gene transfection efficiency. In this study, the transfection efficiency of heparin-conjugated polyethylenimine (HCPEI) with a low molecular weight of 1800 Da was compared to the transfection efficiencies of polyethylenimine with a low molecular weight of 1800 Da (PEI1800), polyethylenimine with a high molecular weight of 25,000 Da (PEI25k), and Lipofectamine. The size of the HCPEI/plasmid DNA (pDNA) complex is approximately 250 nm. HCPEI has a proton-buffering effect and HCPEI/pDNA has higher blood compatibility and a lower cytotoxicity than PEI25k/pDNA and Lipofectamine/pDNA. For in vitro transfection of rabbit smooth muscle cells in serum-free medium, the transfection efficiency of HCPEI/pDNA was not significantly different from those of PEI25k/pDNA and Lipofectamine/pDNA. Importantly, in serum-containing medium, the transfection efficiency of HCPEI/pDNA was significantly higher than those of PEI25k/pDNA and Lipofectamine/pDNA. For vascular endothelial growth factor (VEGF) gene transfection to mouse ischemic limbs, HCPEI/pDNA exhibited significantly higher VEGF expression and more extensive neovascularization than PEI/pDNA and Lipofectamine/pDNA. Taken together, heparin conjugation to PEI improves the in vivo gene transfection efficiency of PEI.

Topics: Animals; Cell Survival; Cells, Cultured; Disease Models, Animal; DNA; Erythrocyte Aggregation; Female; Genetic Therapy; Heparin; Hindlimb; Ischemia; Lipids; Mice; Mice, Inbred C57BL; Molecular Weight; Muscle, Skeletal; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neovascularization, Physiologic; Particle Size; Polyethyleneimine; Rabbits; Rats; Rats, Sprague-Dawley; Transfection; Vascular Endothelial Growth Factor A

The purpose of the current study was to determine the effects of vascular endothelial growth factor (VEGF) on muscle flap survival and vascularity in a rat gracilis ischemia-reperfusion model. A total of 12 adult male Wistar rats were divided into two groups (n = 6). The experimental group received the plasmid encoding VEGF(165) cDNA plus lipofectamine (cationic liposome) injected directly to the gracilis muscle following 4 h of ischemia. The control group received lipofectamine only. The viability and vascularity of the flaps were evaluated after 7 days of reperfusion. The data demonstrated that the VEGF plasmid- and lipofectamine-treated muscle flaps had significantly greater total survival and capillary count 7 days after reperfusion compared with the flaps treated only with lipofectamine. These results indicate that VEGF exerts a protective effect on ischemic skeletal muscle flaps.

Topics: Animals; Cation Exchange Resins; Collateral Circulation; DNA, Complementary; Endothelial Growth Factors; Escherichia coli; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Hindlimb; Ischemia; Lipids; Lymphokines; Male; Microcirculation; Muscle, Skeletal; Plasmids; Rats; Rats, Wistar; Surgical Flaps; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors