Phenotypic alterations in human saphenous vein culture induced by tumor necrosis factor-alpha and lipoproteins: a preliminary development of an initial atherosclerotic plaque model

Abstract

Background: Atherosclerosis is a chronic progressive inflammatory disease of blood vessels particularly the arteries. The development of atherosclerotic plaques or atherogenesis is a complex process that is influenced by cardiovascular risk factors such as vascular inflammation and dyslipidemia. This study demonstrates the ability of tumor necrosis factor-alpha (TNF-α) and low density lipoproteins (LDL) to induce atherosclerotic plaque in human saphenous vein (HSV) organ culture. Methods: Normal HSV segments, from male patients who had coronary bypass graft, were cultured in DMEM containing 5% heat inactivated fetal bovine serum. TNF-α (5 ng/ml) was applied in combination with native LDL (nLDL) or oxidized LDL (oxLDL) at the dose of 50 μg/ml for 14 days. The phenotypic changes of the organ cultures characteristic of initial atherosclerotic plaques were evaluated. The effect of anti-atherogenic agent, 17-β estradiol (E2), was also determined. Results: Histologic, histomorphometric, and immunohistochemical examinations revealed that HSV rings stimulated with TNF-α + nLDL or TNF-α + oxLDL can exhibit the essential morphological features of atherogenesis, including fibrous cap formation, cholesterol clefts, evident thickening of the intimal layer, increased proliferation of smooth muscle cells (SMC) and migration to the subendothelial layer, significant SMC foam cell formation, and increased expression of adhesion molecules in the vascular wall. Addition of E2 (50 nM) to the culture significantly modulated the critical changes. Consistently, mRNA profiling of the HSV model revealed that 50 of 84 genes of atherosclerosis were up-regulated. Conclusions: Phenotypic changes characteristic of the initial development of atherosclerotic plaques can be induced in HSV organ culture.