A venous interposition was placed into the carotid artery of hypercholesterolemic apolipoprotein E3-Leiden (APOE*3-Leiden) mice to induce vein graft thickening with features of accelerated atherosclerosis. To demonstrate the efficacy of the lentiviral shRNA targeting murine CCR2 (shCCR2) in blocking vein graft disease in vivo, lentiviral shCCR2 or a control lentivirus was used to infect the vein graft locally (n = 8).
Vascular CCR2 and MCP-1 messenger RNA expression levels were significantly upregulated during lesion progression in the vein graft. Infection of smooth muscle cells (SMCs) with a lentiviral shRNA targeting shCCR2 completely abolished MCP-1–induced SMC migration and inhibited SMC proliferation in vitro (n = 3 per group). Morphometric analysis of sections of grafts showed a significant 38 % reduction in vein graft thickening in the shCCR2-treated mice 4 weeks after surgery (control, 0.42 ± 0.05 mm2; shCCR2, 0.26 ± 0.03 mm2; P = .007).
Vascular CCR2 contributes to vein graft disease, and local application of shRNA against CCR2 to the vessel wall prevents vein graft thickening in hypercholesterolemic mice, suggesting that local overexpressing of shRNA using organ-targeted lentiviral gene delivery may be a promising therapeutic tool to improve vein graft disease in bypassed patients.