Title: Dietary grape powder increases IL-1ß and IL-6 production by lipopolysaccharide-activated monocytes and reduces plasma concentrations of large LDL-cholesterol particles in obese humans Authors
|Peerson, Jan -|
|Bonnel, Ellen -|
Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2014
Publication Date: May 15, 2014
Citation: Zunino, S.J., Peerson, J., Freytag, T.L., Breksa Iii, A.P., Bonnel, E.L., Woodhouse, L.R., Storms, D.H. 2014. Dietary grape powder increases IL-1ß and IL-6 production by lipopolysaccharide-activated monocytes and reduces plasma concentrations of large LDL-cholesterol particles in obese humans. British Journal of Nutrition. DOI: 10.1017/S0007114514000890. Interpretive Summary: Obesity increases the risk of developing heart disease, diabetes, and bacterial and viral infections compared to people with normal weight. In a 9 wk human study, twenty-four obese volunteers were fed a grape powder or a placebo powder to determine effects of dietary grapes on blood lipids (fats), blood markers of inflammation, and cells of the immune system. The grape powder was made from freeze-dried whole table grapes that included green, red, and purple table grapes. Blood was collected at 6 timepoints during the study, including 2 baseline blood draws and 2 blood draws each during the 3 wk on the grape or placebo powders (at the 2 and 3 wk timepoints). Comprehensive chemistry panels, lipid profile analyses, measurement of plasma inflammatory markers, and measurement of immune cell molecules (cytokines) from activated immune cells were performed for each blood draw. Dietary grape powder reduced plasma concentrations of large LDL cholesterol and large LDL particles compare to the placebo group that are involved in heart disease. Immune cells were isolated from blood at each timepoint and the T cells were activated with antibodies that bound to the cell surface. Monocytes were isolated and activated with a component of bacteria called lipopolysaccharide. The production of immune cell cytokines were measured to show the activation status of the T cells and monocytes. The cytokines interferon-gamma, tumor necrosis factor-alpha, interleukin-4, and interleukin-10 were measured for the activated T cells. The cytokines tumor necrosis factor-alpha, interleukin-1ß, interleukin-6, and interleukin-8 were measured for the activated monocytes. No difference was observed for the production of T cell cytokines between the grape and placebo groups. However, the production of interleukin-1ß and interleukin-6 was increased in the activated monocytes from the group consuming grapes compared to the placebo. These data suggest that dietary grapes may decrease fats in the blood that are linked to heart disease in obese people. Furthermore, consuming the grape powder increased the sensitivity of monocytes and this increased sensitivity may reduce the risk for developing infections in obese individuals.
Technical Abstract: Obesity increases the risk of developing cardiovascular disease, hypertension, type 2 diabetes, and bacterial and viral infections when compared to the normal weight population. In a 9 wk randomised, double-blind crossover study, 24 obese subjects between 20-60 y old and with a BMI between 30-45 kg/m2 were fed grape or placebo powders for 3 wk intervals to determine the effects of dietary grapes on blood lipid profiles, plasma inflammatory markers, and immune function. Blood was collected on day 1 and 8 for baseline information and at wk 3, 4, 8, and 9. Comprehensive chemistry panels, lipid profile analyses by nuclear magnetic resonance, measurement of plasma inflammatory markers, and analyses of cytokine production from activated T lymphocytes and monocytes were performed for each blood draw. Dietary grape powder reduced plasma concentrations of large LDL cholesterol and large LDL particles compare to the placebo group (P < 0.05). Interferon-gamma, TNF-alpha, IL-4, and IL-10 were measured in supernatants from peripheral blood mononuclear cells (PBMC) activated by anti-CD3/CD28 antibodies, and TNF-alpha, IL-1ß, IL-6, and IL-8 were measured in supernatants from PBMC activated with ultrapure lipopolysaccharide. No difference was observed for the production of T cell cytokines between the groups. The production of IL-1ß and IL-6 was increased in the supernatants from LPS-activated PBMCs in the group fed grape powder compared to the placebo. These data suggest that dietary grapes may decrease atherogenic lipid fractions in obese people and increase the sensitivity of monocytes in a population who are at greater risk for developing infections.