Artery interposed to vein did not develop atherosclerosis and underwent atrophic remodeling in cholesterol-fed rabbits

Abstract

Autologous vein grafts interposed to arteries are susceptible to the development of accelerated atherosclerosis. The effect of grafted artery interposed to vein on the atherosclerosis development and vascular remodeling is unknown. We investigated, therefore, the morphologic changes of artery grafts to vein in hyperlipidemic rabbits. Left common carotid artery grafts, approximately 5 cm long, were placed in the right external jugular vein position of 24 New Zealand White rabbits. After surgery, rabbits were fed with high lipid diet for 1, 2, 4 and 12 weeks, respectively. Serum lipid levels were measured and the right common carotid artery and grafted left common carotid artery were harvested at above mentioned time points. Serum lipid levels were also measured in six rabbits receiving normal chow. Vessel wall thickness was measured and analyzed by image processing system. Hyperlipidemia occurred in all rabbits fed with high lipid diet. Fatty streak and atherosclerotic plaques were observed and lipid drops enriched in medial smooth muscle cells in control right common carotid arteries 4 weeks after surgery. In the grafted arteries, no fatty streak and atherosclerotic plaque were seen and the vessel wall thickness decreased continuously after surgery (before surgery: 107.32 +/- 4.57 microm; 1 week: 94.50 +/- 5.78 microm*; 2 weeks: 87.00 +/- 5.32 microm*; 4 weeks: 40.17 +/- 5.11 microm*;12 weeks: 18.00 +/- 4.93 microm*, *p <0.05 versus before surgery). Three months after surgery, grafted arteries possess similar structures as that of veins. The artery interposed to vein did not develop atherosclerosis and underwent atrophic remodeling in cholesterol-fed rabbits suggesting that local hemodynamic load was the most important determinant influencing the development of atherosclerosis.