The existing scientific evidence from both in vitro and clinical trials supports the notion that polyphenols can modulate platelet function. Beyond being central players in haemostasis and thrombosis, platelets have crucial roles in the development of atherosclerosis, mediated through their interactions with monocytes and endothelial cells. Disturbed platelet function correlates with other risk factors, including hypertension and obesity, and the progression of cardiovascular diseases (CVD), postulating platelets as rational targets in CVD prevention. Thus, the effects of polyphenols on disturbed platelet function would contribute to their pleiotropic beneficial effects of on cardiovascular health. Aronia juice is a rich source of polyphenols including anthocyanins, procyanidins, phenolic acids and flavonols. However, there is no clinical evidence on the effects of aronia juice consumption on platelet function and related CVD factors. The purpose of this study is to investigate the effects of Aronia juice polyphenols on platelet function and other CVD risk factors in subjects with moderate CVD risk.
To investigate the effect of Aronia (Aronia melanocarpa L.) juice polyphenols on platelet function and other CVD risk factors a three-arm, crossover design, randomized, double-blind placebo-controlled clinical trial will be performed in apparently healthy subjects at moderate CVD risk. Recruited participants will be randomly assigned to one of three interventions (pure Aronia juice, Aronia beverage or placebo beverage) in the first phase and followed by cross-over in second and third phase. Two-week run-in period with low intake of polyphenols will precede the start of the intervention, ie. the first intervention phase. During each of three intervention periods (phases) subjects will consume 100 ml of each intervention product daily for 28 days, with 28 days of wash out period between different phases. Blood and urine samples will be taken at baseline, before and after 28 days after each intervention period. Platelet analyses by flow cytometry, biochemical analyses of plasma samples, full blood count, blood pressure and anthropometric measurements will be performed at each study visit. During the first study visit, regardless the allocation, blood samples will be taken before and 2h after the consumption of first 100 ml of intervention product (performed at the experimental site) and the analysis of markers of platelet function, biochemical parameters (glucose, triglycerides, and uric acid) and blood pressure will be assessed. Subjects will be instructed to avoid rich-sources of anthocyanins and procyanidins during the whole study. Dietary habits will be assessed by food frequency questionnaire (FFQ) performed 2 times at the beginning and at the end of the study and 24h-recall performed at the beginning and after each wash out period.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
84
Pure Aronia juice with appx. polyphenols content of 1000 mg gallic acid equivalents/100ml
Aronia juice-based beverage with appx. polyphenols content of 250 mg gallic acid equivalents/100ml, obtained as a blend of ¼ vol. of pure Aronia juice and ¾ vol. of placebo beverage.
A polyphenol-free formulation with matched nutrient composition (sugars, vitamins, minerals) and similar sensory characteristics to active interventions
Centre of Research Excellence in Nutrition and Metabolism, Institute for Medical Research, University of Belgrade
Belgrade, Serbia
Changes in the percentage of P-selectin and glycoprotein IIbIIIa (GPIIbIIIa) positive platelets, percentage of platelet-monocyte and platelet-neutrophil aggregates, between baseline and endpoint within the intervention group vs. control group.
Percentage of P-selectin and GPIIbIIIa positive platelets evaluated in total number of 20000 platelets, percentage of platelet-monocyte aggregates in 1000 monocytes and percentage of platelet-neutrophil aggregates in total 20000 neutrophils, all by flow cytometry, in non-treated blood samples and after ex vivo treatment of the whole blood with adenosine-diphosphate (0.5 μM and 20 μM)
Time frame: Baseline, 2 hours and 4 weeks
Changes in serum glucose levels between baseline and endpoint within the intervention group vs. control group.
In 12h-fasting and 2h postprandial serum samples analysed by biochemical analyser.
Time frame: Baseline, 2 hours and 4 weeks
Changes in serum cholesterol levels between baseline and endpoint within the intervention group vs. control group.
Total cholesterol, LDL-cholesterol and HDL-cholesterol levels in 12h-fasting serum samples analysed by biochemical analyser
Time frame: Baseline and 4 weeks
Changes in serum triglycerides levels between baseline and endpoint within the intervention group vs. control group.
In 12h-fasting and 2h postprandial serum samples analysed by biochemical analyser
Time frame: Baseline, 2 hours and 4 weeks
Changes in systolic and diastolic blood pressures between baseline and endpoint within the intervention group vs. control group.
Mean of 3 x 2 consecutive office measurements performed within 30 min at each time point with professional OMRON device
Time frame: Baseline, 2 hours and 4 weeks
Changes in body weight between baseline and 4 weeks within the intervention group vs. control group.
Body weight will be measured by bio-impedance scale
Time frame: Baseline and 4 weeks
Changes in waist circumference between baseline and 4 weeks within the intervention group vs. control group.
Waist circumference will be measured by professional tape, according to the guidelines
Time frame: Baseline and 4 weeks
Changes in body mass index between baseline and 4 weeks within the intervention group vs. control group.
Body mass index will be calculated based on values obtained as body weight in kilograms divided by height in meters squared.
Time frame: Baseline and 4 weeks
Changes in the percentage of body fat between baseline and 4 weeks within the intervention group vs. control group
Body fat as percentage of total weight measured by bio-impedance instrument
Time frame: Baseline and 4 weeks
Changes in the percentage of body water between baseline and 4 weeks within the intervention group vs. control group
Body water as percentage of total weight measured by bio-impedance instrument
Time frame: Baseline and 4 weeks
Changes in total body muscle mass between baseline and 4 weeks within the intervention group vs. control group
Percentages of total body muscle mass in kilograms will be measured by bio-impedance instrument
Time frame: Baseline and 4 weeks
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