Effect of Dietary Phosphatidylinositol on Cholesterol Metabolism in Zucker (fa/fa) Rats

Recent studies have shown that dietary phospholipids, especially phosphatidylcholine and phosphatidylserine, have various beneficial biological effects. However, there are not enough data concerning the physiological function of dietary phosphatidylinositol (PI). The metabolic syndrome, a cluster of metabolic abnormalities such as dyslipidemia, diabetes mellitus, and hypertension, is widespread and increasingly prevalent diseases in industrialized countries. In the present study, we evaluated that the effect of dietary PI on cholesterol metabolism in metabolic syndrome model Zucker (fa/fa) rats. For 4 weeks, rats were fed semisynthetic diets containing either 7% soybean oil or 5% soybean oil plus 2% PI. Dietary PI prevented the mild hypercholesterolemia and hepatic cholesterol accumulation in Zucker (fa/fa) rats. These effects were attributable to an increased fecal bile acid excretion and to the tendencies of decreased ACAT1 mRNA level and increased CYP7A1 mRNA level in the liver. Additionally, dietary PI markedly increased microsomal PI content in the liver of Zucker (fa/fa) rats. Our study suggests that dietary PI normalizes cholesterol metabolism through the enhancement of fecal bile acid excretion in the metabolic syndrome model rats.