Hypercholesterolemia with cholesterol-enriched LDL and normal levels of LDL-apolipoprotein B. Effects of the step I diet and bile acid sequestrants on the cholesterol content of LDL

Ethanol extract of Rubia yunnanensis inhibits carotid atherosclerosis via the PI3K/AKT signaling pathway

Atherosclerosis is a multifactorial vascular disease caused by endothelial dysfunction. Because of adverse reactions to drugs used to treat atherosclerosis. For example, statins, which significantly reduce the burden of atherosclerotic disease, have been associated with muscle toxicity. There is a need to identify novel drugs for the prevention and treatment of atherosclerosis Rubia yunnanensis is a herbs commonly used in Asian countries for its protective effects against cardiovascular diseases. However, the mechanism of action of R. yunnanensis extract in carotid artery atherosclerosis has not been found. The carotid artery is usually used as a site for clinical evaluation of atherosclerosis. The present study aimed to determine the mechanism of action of R. yunnanensis extract in the inhibition of carotid atherosclerosis in apolipoprotein E gene knockout (ApoE-/-) mice. The mechanism of atherosclerosis inhibition was elucidated by detecting the blood lipid level, carotid artery pathology, and the protein expression of PI3K and AKT. The present study demonstrated that ethanol extract of R. yunnanensis reduced lipid levels, intima damage and carotid lipid accumulation and increased p-PI3K/PI3K and p-AKT/AKT protein levels in ApoE-/- mice fed high-fat diet for 12 weeks. It was hypothesized that the effects of R. yunnanensis extract may be achieved by regulation of the phosphatidylinositol-3-kinase/protein kinase B signaling pathway. Ethanol extract of R. yunnanensis decreased carotid atherosclerosis in ApoE-/- mice fed a high-fat diet via the phosphatidylinositol-3-kinase/protein kinase B signaling pathway. Therefore, R. yunnanensis may be a promising option for treating atherosclerosis in the future.

Colesevelam HCl reduces LDL particle number and increases LDL size in hypercholesterolemia

BACKGROUND

Although LDL-cholesterol (LDL-C) remains the target of cholesterol-lowering therapy, high levels of LDL particle numbers better differentiate cardiovascular risk than LDL-C concentrations. Colesevelam HCl, a novel bile acid sequestrant, has also been shown to reduce mean LDL-C by 18% with the maximum dose. The effect of colesevelam HCl on LDL particle number and particle size has not been previously published. LDL particle number and particle size were measured by NMR spectroscopy.

METHODS

In this multi-center, double-blind, placebo-controlled study, 149 patients with moderate hypercholesterolemia (LDL-C > 160 mg/dL [4.14 mmol/L]; triglycerides < 300 mg/dL [3.39 mmol/L]) were randomized to colesevelam HCl (1.5-3.75 g/d) or placebo for 6 weeks.

RESULTS

Colesevelam HCl reduced LDL particle number by 6.8% at a dosage of 3.0 g/d (P = 0.031), and 13.7% (P = 0.0002) at a dosage of 3.75 g/d. Baseline levels of triglycerides or LDL size did not influence changes in LDL particle number. Further, mean LDL particle size increased with colesevelam HCl 3.75 g/d (1.1% increase versus baseline, P < 0.05).

CONCLUSION

For patients with moderate hypercholesterolemia, treatment with colesevelam HCl at the recommended starting dose of 3.75 g/d lowered LDL particle number, and increased mean LDL particle size.

Low-fat, monounsaturate-rich diets reduce susceptibility of low density lipoproteins to peroxidation ex vivo

Oxidative modification of low density lipoprotein (LDL) plays an important role in the process of atherosclerosis. The susceptibility of LDL to oxidation and the amount of peroxidation products formed are influenced by the lipoprotein content of 18:1n-9, 18:2n-6, and the 18:2n-6/18:1n-9 ratio, which is dependent in part on dietary fatty acids. The purpose of this study was to determine if changing from a typical American diet to a low-fat, monounsaturate-rich diet (LFMR) would result in favorable alterations in the fatty acid composition and oxidative profile of LDL in hypercholesterolemic individuals. Free-living postmenopausal hypercholesterolemic women who routinely consumed a diet moderately high in total fat and total saturates (34 and 11%, respectively) followed an LFMR diet (26% fat, 6% saturated fat, and 14% monounsaturated fat) for 6 mon. Sixteen postmenopausal hypercholesterolemic women already following standard low-fat (LF) diets acted as a control for seasonal variations in serum lipids. LDL from randomly selected subjects (LF n = 6, LFMR n = 5) was evaluated. LFMR diets resulted in LDL with increased concentrations and percentages of 18:1n-9, reduced 18:2n-6/18:1n-9 ratio, and lower percentages of 18:2n-6. No significant changes in LDL fatty acids occurred in the LF group. Conjugated diene lag time increased in both groups during copper-induced in vitro oxidation. Only the LFMR group experienced an increase in lipid peroxide lag time and a decrease in lipid peroxide formation. The LFMR diet was well tolerated and may be of therapeutic value in the treatment of hypercholesterolemia.