Effects of Nutraceuticals and Botanicals on Macrophage Cholesterol Efflux: Implications for Atherosclerosis

To date, the literature on high-density lipoprotein (HDL) levels as an inverse risk factor for atherosclerosis has mainly been observational, and it is likely that the metabolism and function of HDL is a more significant determinant of cardiovascular disease. As an example, as cholesterol is effluxed out of macrophages and carried to the liver via HDL for excretion, reduced cholesterol efflux can result in increased cholesterol accumulation. In terms of atherosclerosis risk, increasing cholesterol efflux is theoretically a strategy that can be considered as the groundwork of cardiovascular disease treatment and prevention. However, until now, there has not been a pharmaceutical agent that has effectively increased reverse cholesterol transport (RCT) at all steps of the process. Here is a review of the research on natural compounds present in edible foods and their observed in vitro and in vivo (and even ex vivo) effects on the first step of RCT: macrophage cholesterol efflux. The findings here are preliminary and contradictory, making it hard to translate the evidence on most of these naturally occurring agents into clinical applications

Generation of Large-Scale Vorticity in a Homogeneous Turbulence with a Mean Velocity Shear

An effect of a mean velocity shear on a turbulence and on the effective force which is determined by the gradient of Reynolds stresses is studied. Generation of a mean vorticity in a homogeneous incompressible turbulent flow with an imposed mean velocity shear due to an excitation of a large-scale instability is found. The instability is caused by a combined effect of the large-scale shear motions (''skew-induced" deflection of equilibrium mean vorticity) and ''Reynolds stress-induced" generation of perturbations of mean vorticity. Spatial characteristics, such as the minimum size of the growing perturbations and the size of perturbations with the maximum growth rate, are determined. This instability and the dynamics of the mean vorticity are associated with the Prandtl's turbulent secondary flows. This instability is similar to the mean-field magnetic dynamo instability. Astrophysical applications of the obtained results are discussed.Comment: 8 pages, 3 figures, REVTEX4, submitted to Phys. Rev.