diamide and Arteriosclerosis

To study the effect of diamide on the expression of macrophage inflammatory protein-1 alpha (MIP-1 alpha) in cultured human umbilical vein endothelial cells.. After exposure of the endothelial cells (ECs) to different concentrations of diamide for 4 hours, the MIP-1 alpha mRNA in the cells was detected by nuclease S1 protection assay and the MIP-1 alpha protein in those cells was determined by cell enzyme-linked immunosorbent assay. The chemotactic activity of MIP-1 alpha in the conditioned medium of ECs treated with diamide for peripheral blood monocytes was tested by microfilter method using modified Boyden chambers.. Incubation of ECs with 5 micro mol/L diamide resulted in a 2.4-fold increase in the level of MIP-1 alpha mRNA expression as compared with the control group (t = 8.70, P < 0.05). Exposure of ECs to 1 micro mol/L, 5 micro mol/L and 10 micro mol/L diamide resulted in a 0.9-fold, 1.2-fold, and 0.7-fold increase in the level of MIP-1 alpha protein expression respectively, as compared with the control group (F = 35.65, P < 0.05). Chemotactic assay showed that the migration distance of monocytes towards the conditioned medium (CM) of ECs treated with 5 micromol/L diamide was 99.50 microm +/- 4.31 microm, which was significantly more than the 66.47 microm +/- 3.25 microm towards the conditioned medium of ECs in the non-diamide group, the chemokinetic group (67.03 microm +/- 6.83 microm) and the random migration group (65.40 microm +/- 3.36 microm) (F = 404.31, P < 0.05). The results revealed that there might be chemotactic substances in the conditioned medium of 5 micro mol/L diamide treated ECs. The migration distance of monocytes towards the conditioned medium of the ECs exposed to 5 micromol/L diamide was significantly reduced to 82.80 microm +/- 6.88 microm after the addition of goat anti-human MIP-1 alpha antibody (F = 192.25, P < 0.05), which indicates the chemotactic activity of MIP-1 alpha in the conditioned medium of the ECs in the diamide group.. Diamide, a lipid peroxidation inducer, could stimulate ECs to produce high levels of MIP-1 alpha with chemotactic activity, and may play an important role in atherogenesis through attraction of peripheral blood monocytes into arterial intima.

Topics: Arteriosclerosis; Cells, Cultured; Chemokine CCL4; Diamide; Endothelium, Vascular; Gene Expression; Humans; Macrophage Inflammatory Proteins; Radiation-Sensitizing Agents; RNA, Messenger

Inducing lipid peroxidation injury to cultured EC from human umbilical vein was achieved by treating EC with diamide. When the concentration of diamide reached 0.1 x 10(-4) mol/l, intracellular accumulation of lipid peroxide and EC damage were induced and then increased adherence of monocyte to EC was observed. Monocytes appeared to prefer to adhere onto the surfaces and intercellular spaces of the injured EC. These results suggest that the increased adherence of monocytes to EC injured by lipid peroxidation may play an important role in atherogenesis.

Topics: Arteriosclerosis; Cell Adhesion; Cells, Cultured; Diamide; Endothelium, Vascular; Humans; Lipid Peroxidation; Malondialdehyde; Monocytes; Umbilical Veins

Lipid peroxidation was initiated and then facilitated in the cultured aorta and a defined segment of rabbit carotid artery with thiol-oxidizing agent, diamide. The effects of lipid peroxidation on endothelial cells consisted of damage to the biomembranes and subcellular organelles and inhibition of PGI2 synthesis. Diamide (5 x 10(-3) mol/L) was introduced into a defined segment of carotid artery and perfusion was taken on at various intervals, i.e. for 2 hs, 12 hs, 1 day, 2 days, 3 days, 7 days, and 14 days. Examinations showed injury of the endothelial cells, but neither cell denudation and exposure of the subendothelium was obtained. One day after the injury, a large number of monocytes were seen attaching to the intact endothelium with cell immigration toward the intima. Two weeks later, intimal thickening was obtained. In rabbits fed with cholesterol diet beforehand for 8-10 weeks, this was combined with endothelial cell injuries. There was also atherosclerotic lesions in intima involving proliferation of the smooth muscle cells in the carotid arteries. These results suggested that endothelial cell injury induced by lipid peroxide might play an important role in atherogenesis.

Topics: Animals; Arteriosclerosis; Carotid Arteries; Diamide; Endothelium, Vascular; Hyperlipidemias; In Vitro Techniques; Lipid Peroxidation; Male; Rabbits