Gene therapy to prevent vascular remodeling-vascular smooth muscle cell as a target cell

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Vascular smooth muscle cell (VSMC) migration, proliferation, and matrix synthesis within the intima of vessels play an important role in post-angioplasty restenosis. Coronary artery restenosis remains a major unresolved limitation for interventional cardiology. It results from arterial injury incurred during coronary vascularization and is caused in large part bu neointimal hyperplasia, especially within stents. To develop a new therapeutic strategy, we performed following studies. Akt (PKB) is a serine-threonine protein kinase that is activated by various extracellular stimuli through the phosphatidylinositol 3-kinase (P1 3-kinase) pathway. Akt plays an important role in apoptosis, cell proliferation, glucose metabolism and angiogenesis. VSMCs have three isoforms of myosine heavy chains : SM 1,SM 2 and SM emb. After angioplasty, VSMCs change their phenotype from differentiated phenotype (SM 1 and SM 2) to dedifferentiated one (SM emb). Akt regulates these VSMC phenotypic changes. Aden … More oviral transduction of constitutive-active Akt 1 (Adeno-myrAkt) increased expression of SM 1 and SM2. Conversely, dominant-negative Akt 1 increased SMemb expression. Next, we try to transfect target gene to VSMCs in vivo. Metallic stents coated with a polyurethane emulsion containing plasmid DNA were implanted in rabbit femoral arteries to evaluate transgene delivery and expression in the vessel wall. The expression of the plasmid-encoded marker genes, β-galactosidase, luciferase and green fluorescence protein (GEP), were evaluated at 7 days after implantation. The extent of transgene expression was dependent upon the quantity of DNA loaded onto the stent, no signal was detected in vessel segments that received bare metallic stents or polymer-coated stents lacking plasmid DNA. Finally, co-localization studies identified transgene expression in both vascular smooth muscle cells and macrophages. These data demonstrate the utility of coated stents for the local, dose-dependent delivety of genes to multiple cell types in the vessel wall. Less