It is documented that hyperhomocysteinemia (HHcy) is an independent risk factor for atherosclerosis, but whether elevated plasma homocysteine contributes to the progression of atherosclerosis in aged animals with hypercholesterolemia is still unknown. HHcy was induced in apolipoprotein E (ApoE) knockout mice (male, 32 weeks old) by feeding 2% methionine/low folate (1 mg/kg) diet for 20 weeks. HHcy induced by methionine feeding significantly increased oxidative stress, as measured by thiobarbituric-reactive substances in livers (P < .05) and genetic expression of Cu,Zn-superoxide dismutase, in methionine-fed animals compared with controls (P < .05). Furthermore, lipoprotein profiles were changed, in that low-density lipoprotein-cholesterol was shifted to very low-density lipoprotein in the methionine-supplemented group. However, nuclear factor kappaB activity, atherosclerotic lesions, hepatic glutathione level, lipid profiles, and activities of aspartate aminotransferase and alanine aminotransferase were not significantly different. These findings suggest that HHcy induced by methionine may promote disturbances in lipid peroxidation and modify lipoprotein metabolism but not contribute to the progression of atherosclerotic lesion in aged ApoE knockout mice.

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Dandelion (Taraxacum officinale) a tranditional Oriental medicine, has been known to have anti‐atherogenic effects. However, the mechanism by which dandelion extracts protect against atherosclelosis is not clearly known. This study was designed to explore the effect of dandelion extract on inflammation and oxidative stress, risk factors of early atherosclerosis development. Five group of C57BL/6 mice were given atherogenic diet (control) or diets supplemented with 1.5%, 3% dandelion water extract (DWE I and II) and alcohol extract (DAE I and II) for 6 weeks. Supplementation of dandelion extracts did not affect body weight gain and food intake. sVCAM‐1 and MCP‐1 levels were decreased in dandelion supplemented groups and those levels are profoundly decreased in mice treated with DAE. The mRNA expression of MCP‐1 and VCAM‐1 were also down regulated, while the mRNA expression of eNOS was up regulated in aorta of dandelion supplemented groups than the control group. Hepatic TBARS was significantly decreased and GSH was elevated in dandelion supplemented groups. Furthermore, expressions of Cu/Zn SOD, Mn SOD and catalase were dose dependently up‐regulated in dandelion supplemented groups, while GSH reductase expression was up‐regulated at 1.5%, but down‐regulated at 3% supplementation level. SEM study showed that leukocyte adhesion and its subendothelial migration were more frequently observed in control group than dandelion supplemented groups. These data suggest that supplementation of dandelion extracts may ameliorate the development of atherosclerosis via the anti‐oxidative and anti‐inflammatory processes.