Wild blueberries attenuate risk factors of the metabolic syndrome

Abstract

The ability of a wild blueberry-enriched diet to improve risk factors related to Metabolic Syndrome (MetS) such as endothelial dysfunction and chronic inflammation in the Obese Zucker Rat (OZR), a model of the MetS, was studied. Obese Zucker Rats (OZRs) and their lean controls (LZR) were placed either on a Wild Blueberry-enriched (WB) or a control (C) diet for 8 weeks. Obese Zucker rats exhibited reduced vasoconstrictor response to phenylephrine (Phe) and exaggerated vasorelaxant response to acetylcholine (Ach). WB diet partially restored Phe-induced constrictor responses and attenuated Ach-induced relaxant responses in OZR. Plasma nitric oxide (NO) was significantly attenuated and aortic effluent prostaglandin I 2 PGI 2 concentration significantly increased in the WB diet. Downregulation of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in the OZR aorta was observed in the WB diet. WB consumption decreased plasma concentrations of tumor necrosis factor (TNF)- α (–25.6%, P < 0.05), interleukin (IL)-6 (–14.9%, P < 0.05), C-reactive protein (CRP) (–13.1%, P < 0.05) and increased adiponectin concentration (+21.8%, P < 0.05). Expression of IL-6, TNF- α and nuclear factor (NF)-kB was downregulated in both the liver (–65%, –59% and –25%, respectively) and the abdominal adipose tissue (–64%, –52% and –65%), while CRP expression was downregulated only in the liver (–25%). Thus, WB consumption improved endothelial function and exerted an anti-inflammatory effect in the OZR.