Effect of Polyphenols on Peripheral Vascular Disease.

Overview

Peripheral arterial disease (PAD) is a clinical setting characterized by an exceptionally high risk for cardiovascular events. Oxidative stress seems to play a role in impairing flow-mediated dilation (FMD) and contributing to atherosclerosis in patients with PAD. Cocoa seems to exert artery dilatation via oxidative stress inhibition. OBJECTIVES: To investigate whether in PAD patients, dark chocolate elicits artery dilatation via down-regulation of NOX2, the catalytic core of NADPH oxidase.

Full Title of Study: “Effect of Dark Chocolate on Endothelial Function and Oxidative Stress in Patients With Peripheral Vascular Disease.”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Basic Science
    • Masking: Single (Outcomes Assessor)
  • Study Primary Completion Date: August 2013

Detailed Description

Atherosclerosis represents the major cause of worldwide death; it is a complex phenomenon that encompasses the intricate interplay of classic cardiovascular risk factors, oxidative stress and inflammation. Peripheral artery disease (PAD) is a clinical setting that well represents the model of widespread atherosclerosis. PAD affects 20% of patients over the age of 75. Furthermore, PAD patients are at an exceptionally high risk for cardiovascular events and the majority will eventually die of a cardiac or cerebrovascular etiology. Polyphenol could represent a novel therapeutic strategy to counteract atherosclerosis. During the last decades, a growing interest in polyphenols resulted from prospective and epidemiological studies that showed the beneficial effects of these substances on human health. In particular, polyphenols exert their beneficial effect by inhibition of NADPH oxidase (NOX2), an enzyme directly involved in atherosclerosis; thus, the activation of this enzyme leads to an enhanced production of oxidative stress and inflammatory processes. The objective of this study is to evaluate the effect of polyphenols on oxidative stress and inflammation and on surrogate markers of atherosclerosis in PAD patients. Polyphenols, inhibiting NOX2-mediated oxidative stress and immune-mediated process, could represent a novel therapy to reduce the high risk of cardiovascular events in PAD.

Interventions

  • Dietary Supplement: dark chocolate with crossover to milk chocolate
    • 40 g/d of dark chocolate for 4 weeks followed by wash-out (1 week) and by 40 g/d of milk chocolate for 4 weeks
  • Dietary Supplement: milk chocolate with crossover to dark chocolate
    • 40 g/d of milk chocolate for 4 weeks followed by wash-out (1 week) and by 40 g/d of dark chocolate for 4 weeks.

Arms, Groups and Cohorts

  • Placebo Comparator: milk chocolate
    • dosage form: orally given dosage:40 g milk chocolate (≤35% cocoa) frequency and duration: 40 g/day for one month
  • Active Comparator: dark chocolate
    • dosage form: orally given dosage:40 g dark chocolate (≥85% cocoa) frequency and duration: 40 g/day for one month

Clinical Trial Outcome Measures

Primary Measures

  • endothelial function assessed by flow mediated dilation (FMD)
    • Time Frame: 2 hours after (dark or milk) chocolate ingestion
  • endothelial function assessed by flow mediated dilation (FMD)
    • Time Frame: after 30 days of (dark or milk) chocolate ingestion

Secondary Measures

  • Oxidative stress markers
    • Time Frame: 2 hours after (dark or milk) chocolate ingestion
    • Oxidative stress markers: sNOX2dp, Isoprostanes, NOx
  • Maximal walking distance
    • Time Frame: 2 hours after (dark or milk) chocolate ingestion
  • Ankle Brachial Index (ABI)
    • Time Frame: 2 hours after (dark or milk) chocolate ingestion
  • Oxidative stress markers
    • Time Frame: after 30 days of (dark or milk) chocolate ingestion
    • Oxidative stress markers: sNOX2dp, Isoprostanes, NOx
  • Maximal walking distance
    • Time Frame: after 30 days of (dark or milk) chocolate ingestion
  • Ankle Brachial Index (ABI)
    • Time Frame: after 30 days of (dark or milk) chocolate ingestion

Participating in This Clinical Trial

Inclusion Criteria

Every PAD patient to be enrolled in the study had: 1. claudication (defined as leg pain on walking, disappearing within 10 minutes of standing, of presumed atherosclerotic origin) and 2. ankle/brachial index (ABI), that was assessed as ankle/arm systolic blood pressure ratio by Doppler ultrasonography <0.90 on the worst leg at rest. Patients had to be in stable conditions without abrupt changes of ABI (>20%) in the last month before the enrolment. Exclusion Criteria:

Subjects were excluded from the study if they had liver insufficiency, serious renal disorders (serum creatinine>2.8 mg/dL), acute stroke, acute myocardial infarction, deep venous thrombosis or if they were current smokers or were taking antioxidants.

Gender Eligibility: All

Minimum Age: 20 Years

Maximum Age: 90 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • University of Roma La Sapienza
  • Provider of Information About this Clinical Study
    • Principal Investigator: Francesco Violi, Full professor of Internal Medicine – University of Roma La Sapienza
  • Overall Official(s)
    • Francesco Violi, MD, Principal Investigator, Sapienza University

References

Loffredo L, Carnevale R, Cangemi R, Angelico F, Augelletti T, Di Santo S, Calabrese CM, Della Volpe L, Pignatelli P, Perri L, Basili S, Violi F. NOX2 up-regulation is associated with artery dysfunction in patients with peripheral artery disease. Int J Cardiol. 2013 Apr 30;165(1):184-92. doi: 10.1016/j.ijcard.2012.01.069. Epub 2012 Feb 14.

Carnevale R, Loffredo L, Pignatelli P, Nocella C, Bartimoccia S, Di Santo S, Martino F, Catasca E, Perri L, Violi F. Dark chocolate inhibits platelet isoprostanes via NOX2 down-regulation in smokers. J Thromb Haemost. 2012 Jan;10(1):125-32. doi: 10.1111/j.1538-7836.2011.04558.x.

Loffredo L, Carnevale R, Perri L, Catasca E, Augelletti T, Cangemi R, Albanese F, Piccheri C, Nocella C, Pignatelli P, Violi F. NOX2-mediated arterial dysfunction in smokers: acute effect of dark chocolate. Heart. 2011 Nov;97(21):1776-81. doi: 10.1136/heartjnl-2011-300304. Epub 2011 Jul 31.

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