Der liposomale Gentransfer von C-Natriuretischem Peptid (CNP) verhindert die Bildung von Neointima und fördert das Wachstum von Endothelzellen

Abstract

Background: C-type natriuretic peptide (CNP) reduces proliferation of smooth muscle cells (SMCs) and stimulates endothelial growth. We investigated the long-term therapeutic effects of adventitial liposome-mediated CNP gene or peptide application in a porcine restenosis model. Methods: For in vitro applications, primary cultures of porcine SMCs and endothelial cells (ECs) were used. Gene transfer was performed with cationic lipid DOCSPER. In vivo treatment of pig femoral arteries was adventitial using a needle injection catheter following balloon over-dilation in 11 pigs, 5 pigs served as controls. Arteries were then investigated using angiography, Evan’s blue staining, histomorphometry, immunohistochemistry, PCR and RT-PCR at 3 weeks or 3 months. Results: Using CNP gene transfer in vitro, 29 ± 7% reduction of cell proliferation in SMCs and 22 ± 6% enhancement of cellular growth in ECs was observed with minimal cytotoxicity of 5 ± 2%. CNP peptide demonstrated in SMC 50 ± 11% reduction of cell proliferation with 30 ± 6% toxicity and 12 ± 5% enhancement of cellular growth of ECs without toxic effects. Three weeks following application in vivo Evan’s blue staining demonstrated intactness of endothelium in controls and therapy groups. Minimal neointima formation was observed at three months using CNP gene (CNP Plasmid 1,7 ± 0,4% restenosis, CNP protein 5,6 ± 1,7% restenosis, control 15,6 ± 4,8% restenosis; p < 0.05). Conclusions: Periadventitial liposome-mediated CNP gene transfer in vivo resulted in rapid endothelial repair and significant long-term reduction of neointimal formation and was superior over single CNP peptide administration. Advantages of CNP are its physiological origin and simultaneous inhibition of SMC proliferation and promotion of EC growth.