Poster Topical Area: Methods and Protocols

Location: Hall D

Poster Board Number: 683

P15-022 - Blueberries for Improving Vascular Endothelial Dysfunction in Postmenopausal Women with Elevated Blood Pressure and Stage 1-Hypertension: Study Protocol

Monday, Jun 11
8:00 AM – 3:00 PM

Objectives: Accumulating evidence indicates the blood pressure (BP)-lowering and vascular-protective effects of blueberries; however, it remains unknown whether blueberry consumption can improve vascular endothelial function in postmenopausal women with elevated BP and stage 1-hypertension (HTN). The objective of this study is to evaluate the efficacy of blueberries to improve vascular endothelial function in postmenopausal women with elevated BP and stage 1-HTN, and to identify underlying mechanisms. A randomized, double-blind, placebo-controlled, parallel-arm clinical trial was designed to test the following hypotheses: 1) daily consumption of 22 g freeze-dried blueberry powder for 12 weeks will improve vascular endothelial function assessed as endothelium-dependent dilation (EDD), 2) improvements in EDD will be mediated by reductions in vascular oxidative stress and inflammation, and 3) blueberry polyphenol metabolism will result in a measureable metabolite signature that correlates with improvements in EDD.


Methods:
Postmenopausal women (n = 58) aged 45-65 years with elevated BP (120-129/<80) or stage 1-HTN (130-139/80-89 mmHg), and with impaired EDD at baseline, are being recruited. Participants are randomized to consume either 22/d freeze-dried blueberry powder or placebo powder for 12 weeks. EDD is assessed by brachial artery flow-mediated dilation (FMDBA) at baseline and 12-weeks. To determine whether improvements in EDD following daily blueberry consumption for 12 weeks are mediated by decreased oxidative stress, changes in FMDBA will be assessed following acute inhibition of oxidative stress with intravenous ascorbic acid. Venous endothelial cells are biopsied at baseline and 12 weeks and will be analyzed for expression of proteins associated with nitric oxide bioavailability, oxidative stress and inflammation via quantitative immunofluorescence. Plasma blueberry polyphenol metabolites will be analyzed via mass spectrometry and statistically compared with measures of EDD.


Conclusion:
We expect that blueberry consumption will improve vascular endothelial function in postmenopausal women with elevated BP and stage-1 HTN through reductions in vascular oxidative stress and inflammation, and that improvements will be linked to blueberry polyphenol metabolism.




Funding Source: Funded by the U.S. Highbush Blueberry Council

CoAuthors: Frank Dinenno, PhD – Colorado State University; Douglas Seals, PhD – University of Colorado-Boulder; Jennifer Richards, PhD – Colorado State University; Kerry Hildreth, MD – University of Colorado Anschutz Medical Campus; Sangeeta Rao, PhD – Colorado State University; Sarah Johnson, PhD, RDN – Colorado State University

Nicole S. Litwin

Doctoral Student
Department of Food Science and Human Nutrition, Colorado State University
Fort Collins, Colorado