Safety evaluation of phytosterols in laying hens: effects on laying performance, clinical blood parameters, and organ development.

Phytosterols are intended for use as a novel food ingredient with plasma cholesterol-lowering activity. Although phytosterols are naturally present in the normal diet, daily consumption is insufficient to ensure plasma cholesterol-lowering levels. Therefore, phytosterols may be added to the diets to achieve the desired cholesterol-lowering activity. A subchronic laying hen safety study was conducted to examine if high-dose phytosterols could affect the safety of hens. Three hundred sixty 21-wk-old Hy-Line Brown laying hens were randomly assigned to 5 groups with 6 replicates of 12 birds each; after 3 wk, birds were fed diets supplemented with 0, 20, 80, 400, and 800 mg/kg of phytosterols for 12 wk. Throughout the study, clinical observations and laying performance were measured. At the end of the study, birds were subjected to a full postmortem examination: blood samples were taken for clinical pathology, selected organs were weighed, and specified tissues were taken for subsequent histological examination. No treatment-related changes that were considered to be of toxicological significance were observed. Therefore, a nominal phytosterol concentration of 800 mg/kg was considered to be the no-observed-adverse-effect level.

Restorative effect of shosaikoto (kampo medicine) on diminution of nitric oxide synthesis in murine peritoneal macrophages induced by hypercholesterolemia.

Macrophages play important roles both in immune response and in lipid metabolism and contribute to the development of atherosclerosis. To clarify the mechanism by which Shosaikoto, a Kampo medicine, shows anti-atherosclerotic action, we studied its effect on macrophage function. The production of nitric oxide (NO), prostaglandin E2 and interleukin 1 by macrophages in mice was reduced by feeding of a cholesterol-enriched diet, and the reduced production was observed 1 week after the beginning of cholesterol feeding. Furthermore, although oxidized low density lipoprotein (LDL) and lysophosphatidylcholine (LPC) reduced NO production, macrophages prepared from mice treated with Shosaikoto at a dose of 1.2 g/kg/d restored the reduced NO production by them as well as by hypercholesterolemia. When the content of LPC was measured, no difference was observed between mice fed a cholesterol-enriched diet in the presence or absence of Shosaikoto treatment, suggesting that the restorative effect of Shosaikoto is not due to the inhibition of LPC production or accumulation. Conclusively, Shosaikoto prevents the modification of macrophage function induced by atherogenic factors, which is probably linked to its displayed anti-atherosclerotic action.

Anti-hyperlipidemic and anti-atherosclerotic actions of shosaikoto (kampo medicine).

We investigated the anti-atherosclerotic action shown by Shosaikoto, a Kampo medicine, using hypercholesterolemic mice. Oral administration of Shosaikoto significantly suppressed the elevation of serum cholesterol in C57BL/6 mice fed a 1.25% cholesterol-enriched diet for four weeks and improved the T cell ratio in peripheral blood, which decreased with the increase of the serum cholesterol level. In addition, Shosaikoto reduced the accumulation of cholesteryl oleate, which alters macrophages into foam cells, after the treatment of macrophages with oxidized or acetylated low density lipoprotein (LDL). Enzymatic study revealed that the treatment of macrophages with oxidized LDL enhanced acyl-coenzyme A: cholesterol acyltransferase (ACAT) activity and markedly reduced neutral cholesteryl ester hydrolase (NCEase) activity. Shosaikoto treatment prevented a decrease in the NCEase activity, however due to the oxidized LDL treatment, although it slightly augmented ACAT activity. Thus, Shosaikoto, which is known to modulate the immune system, improves macrophage and lymphocyte functions diminished by hypercholesterolemia, resulting in an anti-atherosclerotic action.

Shosaikoto (kampo medicine) protects macrophage function from suppression by hypercholesterolemia.

The feeding of cholesterol-enriched diet for 2 weeks was enough to reduce nitric oxide (NO), prostaglandin E(2) (PGE(2) and interleukin-1 (IL-1) productions in thioglycollate-elicited murine macrophages. Although not showing anti-hypercholesterolemic action against ICR mice, Shosaikoto, a Kampo medicine, partially prevented the reduction of NO and IL-1 productions induced by the feeding of cholesterol-enriched diet, and completely released the reduction of PGE(2) production. These data suggest that the malfunction of macrophage induced by hypercholesterolemia may contribute to early atherogenesis and that Shosaikoto retains macrophage function to prevent the development of atherosclerosis, even though serum cholesterol is markedly increased.

Effect of Shosaikoto (Kampo medicine) on the adherence of monocytes in hypercholesterolemic rabbit.

Monocytes/macrophages are known to be involved in atherogenesis, and the adherence of monocytes to the endothelium is considered an earliest characteristic of atherogenesis. Therefore, we studied the mechanism by which Shosaikoto, a Kampo medicine, shows anti-atherosclerotic action, which has been already shown in hypercholesterolemic rabbits. Hypercholesterolemia in rabbits gradually reduced the monocyte number in peripheral blood, whereas Shosaikoto treatment suppressed this decrease in circulating monocytes. Furthermore, although monocytes from hypercholesterolemic rabbits increased in adherence to endothelial cells even without lipopolysaccharide (LPS) activation, Shosaikoto treatment reduced the enhanced adherence observed in monocytes from hypercholesterolemic rabbits. These data suggested that the anti-atherosclerotic action shown by Shosaikoto resulted partly from the suppression of the enhanced adherence characteristic of hypercholesterolemia.