Dietary polyenylphosphatidylcholine decreases cholesterolemia in hypercholesterolemic rabbits - Role of the hepato-biliary axis

The aim of this work was to study the cholesterol-lowering mechanisms induc ed by dietary soybean lecithin in hypercholesterolemic rabbits. Male New Ze aland white rabbits (n = 6 in each group) were fed for 10 weeks either a lo w-fat control C diet, containing 27 g fat/kg, or high-fat diets enriched wi th 2 g cholesterol/kg and 77 g fat/kg. The high-fat diets contained 50 g la rd (L), 50 g soybean triacylglycerol (SO), or 50 g pure soybean phosphatidy lcholine (PLE). PLE diet decreased by 30% beta-VLDL-cholesterol, compared w ith SO diet. HDL2-, HDL3- and LDL-lipid contents were unchanged in the L, S O and PLE groups. In gallbladder bile, amounts of phospholipids, bile salts and cholesterol were significantly increased in PLE group by respectively 45%, 11% and 44%, in comparison with SO group. Intestinal and hepatic Hydro xy Methyl Glutaryl Coenzyme A reductase activities were not increased by PL E diet. Triacylglycerol hepatic content was lower in PLE group than in L or SO groups. Compared with triacylglycerol enriched diet, phosphatidylcholin e enriched diet developed significant higher cholesterol- and triacylglycer ol-lowering effects by a two-step mechanism: i) by reducing the beta-VLDLs, ii) by enhancing the secretion of bile cholesterol. Such results constitut e promising effects of soybean phosphatidylcholine at the hepato-biliary le vel, in the treatment or prevention of hyperlipidemia and related atheroscl erosis. (C) 2000 Elsevier Science Inc. All rights reserved.