Increased expression of connexin43 on the aortic valve in the hypercholesterolemic rabbit model.

BACKGROUND: Aortic valve sclerosis is associated with increased risk of cardiovascular death and myocardial infarction. However, the relevance of connexin43 in aortic valve sclerosis remains unclear. We hypothesized that the mechanism regulating aortic valve sclerosis is associated with the alteration of cell-to-cell communication. METHODS: Twenty male New Zealand rabbits were divided into two groups. Group 1 (n = 10) were fed a normal chow diet, while those in group 2 (n = 10) received a diet containing 1% cholesterol for 12 weeks. After utanizing the animals, the aortic valves were excised for analysis. RESULTS: Myofibroblasts and macrophages were more highly expressed in the cholesterol diet group. Osteopontin and connexin43 were found to concentrate within the endothelial layer on the aortic side of the valve leaflets in the cholesterol diet group. A real-time polymerase chain reaction revealed increased connexin43 and osteopontin mRNA levels in the hypercholesterolemic aortic valves. CONCLUSIONS: The present study demonstrates that hypercholesterolemia increases the expression of connexin43 in the rabbit aortic valve. The results suggest that alterations in gap junctional intercellular communication via connexin43 gap junctions may play a role in the development of aortic valve sclerosis.

Resveratrol attenuates the expression of HMG-CoA reductase mRNA in hamsters.

We investigated the hypolipidemic effect of resveratrol focused on the mRNA expression and hepatic HMG-CoA reductase (HMGR) activity in hamsters fed a high-fat diet. Male Syrian Golden hamsters were fed a high-fat diet containing 0.025% fenofibrate or 0.025% resveratrol for 8 weeks. The concentrations of serum total cholesterol and triglyceride were significantly lower in the resveratrol-fed group than in the control group. The resveratrol contained diet significantly decreased Apo B, Lp(a), and cholesterol-ester-transport protein (CETP) concentrations, but increased Apo A-I levels and the Apo A-I/Apo B ratio. The contents of cholesterol and triglyceride in hepatic tissue were significantly lower in the resveratrol group than in the control group. Real-time PCR analysis revealed that HMGR mRNA expression was significantly lower in the resveratrol group than in the control group. These results indicate that dietary resveratrol reduces serum cholesterol by down-regulating hepatic HMGR mRNA expression in hamsters fed a high-fat diet.

Hypolipidemic effect of soluble fiber isolated from seeds of Cassia tora Linn. in rats fed a high-cholesterol diet.

Soluble fibers isolated from the seeds of Cassia tora Linn. (SFC) have attracted considerable attention in recent years due to their phenomenal rheological behavior. In this study were investigated the effects of SFC on lipid metabolism. Male Sprague-Dawley rats were fed one of three experimental diets, a normal diet, a high-cholesterol diet, or a high-cholesterol diet with 5% SFC, for 5 weeks. The serum concentration of total cholesterol in rats fed SFC was 27% lower (p < 0.05) compared to that of the control group, but the serum high-density lipoprotein cholesterol level was increased in the SFC group. Liver total cholesterol and triglyceride levels were reduced significantly (p < 0.05) in rats fed the SFC diet. In addition, fecal bile acid and lipid excretion was significantly increased by SFC consumption. These results indicate that SFC enhances fecal lipid excretion and may cause a reduction in serum and hepatic lipid concentrations in rats.

Effects of Cassia tora fiber supplement on serum lipids in Korean diabetic patients.

Cassia tora fiber supplement consisting of 2 g of soluble fiber extracted from Cassia semen (C. tora L.), 200 mg of alpha-tocopherol, 500 mg of ascorbic acid, and 300 mg of maltodextrin was formulated in a pack, and given to 15 type II diabetic subjects (seven men and eight women 57.1 +/- 2.9 years old) with instructions to take two packs per day for 2 months. Placebo contained maltodextrin only with a little brown caramel color. Lifestyle factors and dietary intakes of the subjects were not altered during the 2-month period. Serum total cholesterol was moderately (P < .1) decreased in the C. tora group compared with the age- and gender-matched placebo group, as was the ratio of apolipoprotein B to apolipoprotein A1 (P < .1). Levels of serum triglycerides and low-density lipoprotein-cholesterol tended to decrease more in the C. tora-supplemented group than in the placebo group. Serum alpha-tocopherol was increased (P < .01) but lipid peroxides were not significantly lower in the C. tora group. Fasting blood glucose, hemoglobin A1c, blood urea nitrogen, creatinine, and activities of serum aspartate aminotransferase and alanine aminotransferase were not changed by the fiber supplement. We concluded that C. tora supplements can help improve serum lipid status in type II diabetic subjects without serious adverse effects.

Dietary conjugated linoleic acid reduces lipid peroxidation by increasing oxidative stability in rats.

The antioxidative effect of conjugated linoleic acid (CLA) was examined by determining lipid peroxidation and antioxidative enzyme activities. Male Sprague-Dawley rats were fed one of the experimental diets-normal diet, vitamin E-deficient control diet, 0.5% CLA vitamin E-deficient diet, or 1.5% CLA vitamin E-deficient diet for 5 wk. Hepatic thiobarbituric acid reactive substances (TBARS) were increased in the vitamin E-deficient control group, but they were was significantly lowered in the CLA groups. Similarly, hepatic glutathione peroxidase activity was increased in the vitamin E-deficient diet and reduced by CLA supplementation. In addition, CLA caused a significant decrease in superoxide dismutase activity while having no effect on catalase activity. Analyses of the fatty acid composition revealed that dietary CLA was incorporated into hepatic microsomal membrane dose-dependently. Compared to the vitamin E-deficient control, CLA resulted in significantly higher saturated and monounsaturated fatty acids (palmitic and oleic acids) while lowering levels of oxidation-susceptible polyunsaturated fatty acids (linoleic, linolenic, and arachidonic acids) in both plasma and hepatic membrane. The concentrations of plasma cholesterol and triacylglycerol (TG) were lower in the 1.5% CLA group than in other groups. These results suggest that dietary CLA has antiatherosclerotic and antioxidant activity by increasing oxidative stability in plasma and hepatic membrane in the vitamin E-deficient rats.