Effect of Polyphenols on Peripheral Vascular Disease.

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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Effect of Dark Chocolate on Endothelial Function and Oxidative Stress in Patients With Peripheral Vascular Disease.

Conditions
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Peripheral Arterial Disease

Intervention / Treatment
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* Dietary Supplement: dark chocolate with crossover to milk chocolate
* Dietary Supplement: milk chocolate with crossover to dark chocolate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Every PAD patient to be enrolled in the study had: claudication (defined as leg pain on walking, disappearing within 10 minutes of standing, of presumed atherosclerotic origin) and 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.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: milk chocolate<br>dosage form: orally given dosage:40 g milk chocolate (≤35% cocoa) frequency and duration: 40 g/day for one month | Dietary Supplement: milk chocolate with crossover to dark chocolate<br>* 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.<br>|
| Active Comparator: dark chocolate<br>dosage form: orally given dosage:40 g dark chocolate (≥85% cocoa) frequency and duration: 40 g/day for one month | Dietary Supplement: dark chocolate with crossover to milk chocolate<br>* 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<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| endothelial function assessed by flow mediated dilation (FMD) |  | 2 hours after (dark or milk) chocolate ingestion | 
| endothelial function assessed by flow mediated dilation (FMD) |  | after 30 days of (dark or milk) chocolate ingestion | 

Secondary Outcome Measures

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

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Peripheral arterial disease, Oxidative stress, Cocoa, polyphenols, NADPH oxidase