ABSTRACT
BACKGROUND: Hyperhomocysteine is an independent risk factor of coronary heart disease (CHD). However, whether hyperhomocysteine affects the progression of atherosclerosis is unclear. In the present study, we examined the effect of hyperhomocysteine on the formation of atherosclerosis in low-density lipoprotein receptor-deficient (LDLr(-/-)) mice. METHODS: Forty-eight 7-week-old LDLr(-/-) mice were assigned to the following groups: mice fed a standard rodent diet (control group), mice fed a high-methionine diet (high-methionine group), mice fed a high-fat diet (high-fat group), and mice fed a diet high in both methionine and fat (high-methionine and high-fat group). At the age of 19, 23, and 27 weeks, four mice at each interval in every group were sacrificed. RESULTS: At the end of the study, mice did not show atherosclerotic lesions in the aortic sinus and aortic surface until 27 weeks old in the control group. However, atherosclerotic lesions developed in the other three groups at 19 weeks. The amount of atherosclerotic lesions on the aortic surface was lower in the high-methionine group than in the high-fat group (P < 0.001). Atherosclerotic lesions on the aortic surface in the high-methionine and high-fat group were the most severe. The mean area of atherosclerotic lesions in the aortic sinus compared with atherosclerotic lesions on the aortic surface was lower in the high-methionine group than in the high-fat group (P < 0.001). Atherosclerotic lesions in the aortic sinus in the high-methionine and high-fat group were the most severe. CONCLUSIONS: Homocysteinemia accelerates atherosclerotic lesions and induces early atherosclerosis independently in LDLr(-/-) mice. Reducing the level of homocysteinemia may be beneficial for prevention and treatment of CHD.
ABSTRACT
OBJECTIVE: To test the influence of homocysteine on the production and activation of matrix metalloproteinase-2 (MMP-2) and tissue inhibitors of matrix metalloproteinase-2 (TIMP-2) and on cell migration of cultured rat vascular smooth muscle cells (VSMCs). Also, to explore whether rosuvastatin can alter the abnormal secretion and activation of MMP-2 and TIMP-2 and migration of VSMCs induced by homocysteine. METHODS: Rat VSMCs were incubated with different concentrations of homocysteine (50-5000 µmol/L). Western blotting and gelatin zymography were used to investigate the expressions and activities of MMP-2 and TIMP-2 in VSMCs in culture medium when induced with homocysteine for 24, 48, and 72 h. Transwell chambers were employed to test the migratory ability of VSMCs when incubated with homocysteine for 48 h. Different concentrations of rosuvastatin (10(-9)-10(-5) mol/L) were added when VSMCs were induced with 1000 µmol/L homocysteine. The expressions and activities of MMP-2 and TIMP-2 were examined after incubating for 24, 48, and 72 h, and the migration of VSMCs was also examined after incubating for 48 h. RESULTS: Homocysteine (50-1000 µmol/L) increased the production and activation of MMP-2 and expression of TIMP-2 in a dose-dependent manner. However, when incubated with 5000 µmol/L homocysteine, the expression of MMP-2 was up-regulated, but its activity was down-regulated. Increased homocysteine-induced production and activation of MMP-2 were reduced by rosuvastatin in a dose-dependent manner whereas secretion of TIMP-2 was not significantly altered by rosuvastatin. Homocysteine (50-5000 µmol/L) stimulated the migration of VSMCs in a dose-dependent manner, but this effect was eliminated by rosuvastatin. CONCLUSIONS: Homocysteine (50-1000 µmol/L) significantly increased the production and activation of MMP-2, the expression of TIMP-2, and the migration of VSMCs in a dose-dependent manner. Additional extracellular rosuvastatin can decrease the excessive expression and activation of MMP-2 and abnormal migration of VSMCs induced by homocysteine.
