Black Raspberry Extract Increased Circulating Endothelial Progenitor Cells and Improved Arterial Stiffness in Patients with Metabolic Syndrome: A Randomized Controlled Trial

Abstract Administration of black raspberry (Rubus occidentalis) is known to improve vascular endothelial function in patients at a high risk for cardiovascular (CV) disease. We investigated short-term effects of black raspberry on circulating endothelial progenitor cells (EPCs) and arterial stiffness in patients with metabolic syndrome. Patients with metabolic syndrome (n = 51) were prospectively randomized into the black raspberry group (n = 26, 750 mg/day) and placebo group (n = 25) during the 12-week follow-up. Central blood pressure, augmentation index, and EPCs, such as CD34/KDR+, CD34/CD117+, and CD34/CD133+, were measured at baseline and at 12-week follow-up. Radial augmentation indexes were significantly decreased in the black raspberry group compared to the placebo group (−5% ± 10% vs. 3% ± 14%, P < .05). CD34/CD133+ cells at 12-week follow-up were significantly higher in the black raspberry group compared to the placebo group (19 ± 109/μL vs. −28 ± 57/μL, P < .05). Decreases from the baseline in...