Cholesterol-lowering effect of non-viscous soluble dietary fiber NUTRIOSE (R) 6 in moderately hypercholesterolemic hamsters

International audienceNUTRIOSE (R) 6 is a new wheat starch-based low-digestible carbohydrate. This study investigated the effect of this soluble non-viscous fiber on cholesterol metabolism. Hamsters fed with 0.25% cholesterol-enriched diet (CHO) were given graded amounts of NUTRIOSE (R) 6, i.e. 0% (cellulose, CHO), 3% (N3), 6% (N6) or 9% (N9) (w:w). As compared to CHO diet, 9% NUTRIOSE (R) 6 significantly lowered plasma and LDL cholesterol by 14.5 and 23.8%, respectively. The LDL-cholesterol lowering effect was also significant with the 6% dose (-21.4%). NUTRIOSE (R) 6 diets prevented hepatic cholesterol accumulation (-10 to -20%) and significantly decreased bile cholesterol (-47 to -68%) and phospholipids (-30 to -45%) concentrations. The 9% NUTRIOSE (R) 6 diet significantly decreased the rate of dietary cholesterol absorption (-25%) and markedly stimulated faecal neutral sterol (+81%) and bile salts (+220%) excretion. No significant change in cholesterol 7-alpha-hydroxylase or LDL-receptor activities was observed whereas 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was reduced by 29%. Reduced cholesterol and bile salt absorptions and lowered cholesterol synthesis are likely mechanisms underlying the cholesterol lowering effect of NUTRIOSE (R) 6. Results suggest the use of NUTRIOSE (R) 6 as a new dietary cholesterol-lowering agent that should be tested in humans as treatment and evenly prevention of mild hypercholesterolemia

The endothelial cholesterol efflux is promoted by the high-density lipoprotein anionic peptide factor

International audienceThe prevention of atherosclerosis depends on the high-density lipoprotein (HDL) capacity to stimulate the efflux of unesterified cholesterol (UC). We tested here the effects of 2 HDL apolipoproteins, apo A-I and the 7-kd anionic peptide factor (APF), on the UC efflux by human endothelial ECV 304 cells in culture. Apolipoprotein A-I (10 lmol/L) or APF (3.5 lmol/L) in lipid-free forms or small particles (13 nm with apo A-I or 19 nm with APF) were incubated in the presence of [4-14C]UC. The phosphatidylcholines (PCs) were present either at a low level (0.35 mmol/L with apo A-I or 0.20 mmol/L with APF) or at a high level (1 mmol/L with apo A-I). We also tested either large 53-nm bile lipoprotein complex–like particles (3.5 lmol/L APF [13 lg/500 lL]) with a high PC level (0.65 mmol/L) or a 9-residue synthetic peptide (13 lg/500 lL), derived from the NH2-terminal domain of HDL3-APF, in a lipid-free or low-lipidated (0.20 mmol/L PCs) form. A control was developed in absence of the added compounds. A rapid [4-14C]UC efflux mediated by APF added in free form or in 19-nm complexes was 2.2- to 2.3-fold higher than that mediated by apo A-I in free form or in 13-nm particles ( P b .05). The level of this high APFrelated efflux was comparable with that obtained with the 12-nm native HDLs (10 lmol/L apo A-I) or free PCs (1 mmol/L). The increase in the UC efflux was much more limited (1.4-fold) in the presence of the 53-nm APF/high-PC particles, but it was higher than that mediated by apo A-I. In addition, the efflux mediated by the synthetic peptide, in lipid-free or low-lipidated form, constituted the major part of that related to the full-length APF. Thus, all these particles are very active HDL components, able to act as cholesterol acceptors. Interestingly, we further showed a new anti-atherogenic property of APF as well as its metabolic importance and clinical relevance. By its involvement in the first step of the reverse cholesterol transport, APF could reduce the risk of cardiovascular disease