In humans, after a hyperlipidemic meal, an alteration of the endothelial function has been described, that occurred simultaneously with the peak of plasma triglycerides and markers of oxidative stress and inflammation. Polyphenols intake, especially flavonoids, has been described to exert beneficial effects on cardiovascular function. However, the effect of polyphenols endothelial function, inflammation and oxydative stress in postprandial state is unknown in dogs.

Our aim was to assess the effects of a single administration of polyphenols extracted from grape seed on endothelial function inflammatory status and oxydative stress in postprandial state in dogs. Method Ten healthy adult beagles were enrolled in this Latin-square study. Dogs received 4 meals separates of a 1-week wash-out period a standard meal, a standard meal and polyphenols, a hyperlipidic meal (a standard meal and sunfloweroil and a hyperlipidic meal and polyphenols. Flow mediated dilatation (FMD), triglycerides, total cholesterol, HDL-Cholesterol, Malondialdehyde, CRP, serumamyloid A, Haptoglobine were assayed before, 2 and 4h after the meal.

FMD was higher 4h after standard meal with polyphenols compared to the standard meal, but was unchanged after the hyperlipidic meal and polyphenols compared to the hyperlipidic meal. The plasma concentration of haptoglobin was higher after a hyperlipidic meal compared to a standard meal but not after a hyperlipidic meal and polyphenols.

At the dose we used, a single administration of polyphenols improved endothelial function after the standard meal but seemed to be inefficient to counterbalance the effects of the hyperlipidic meal. Moreover, the polyphenols intake abolished the higher haptoglobine concentration measured after the high-fat meal. Our study suggests that a single administration of polyphenols could induce an upgrade of postprandial inflammation associated with an improvement in endothelial function in dogs.