Wild blueberries attenuate risk factors of the metabolic syndrome

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 I2 PGI2 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)(–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, TNFand 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 down regulated only in the liver (–25%). Thus, WB consumption improved endothelial function and exerted an anti-inflammatory effect in the OZR.