Improvement of Endothelial Function by EGCG

Study Overview
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Brief Summary
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Cardiovascular diseases are a major cause of morbidity and mortality worldwide. Impaired endothelial function (assessed as flow-mediated dilation) represents an early marker for later cardiovascular events. Epidemiological and experimental studies suggest that consumption of tea is associated with lower progression of atherosclerosis and reduced cardiovascular mortality. Tea contains high amounts of polyphenols with important biological activities. The green tea catechin epigallocatechin-3-gallate (EGCG) is the most potent physiologically active compound in vitro. However, little is known about its contribution to beneficial effects of tea in vivo. In this crossover study the impact of a single dose of EGCG applied in different forms (green tea beverage, green tea extract and EGCG) on flow-mediated dilation is investigated in healthy volunteers two hours after ingestion. The amount of EGCG (200 mg) corresponds to appr. 0.5 L of green tea. The results of the study will elucidate the contribution of EGCG in cardiovascular protective effects of green tea in vivo. The outcomes will provide insights about the role of EGCG in different application forms to improvements of endothelial function in humans.

Official Title
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The Role of EGCG in Different Application Forms on Flow-mediated Dilation in Healthy Volunteers

Conditions
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Cardiovascular Diseases

Intervention / Treatment
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* Dietary Supplement: Green tea beverage
* Dietary Supplement: Green tea extract
* Dietary Supplement: EGCG
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male healthy volunteers 20-50 years BMI < 27 kg/m2 Cholesterol < 240 mg/dl Exclusion Criteria: Diabetes mellitus Hypertension Conditions with impaired endothelial function Smoking Regular drug use Alcohol abuse Regular tea drinkers

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Green tea beverage<br>200 mg EGCG as green tea beverage. | Dietary Supplement: Green tea beverage<br> <br> |
| Active Comparator: Green tea extract<br>200 mg EGCG as green tea extract and same volume water as for tea beverage. | Dietary Supplement: Green tea extract<br> <br> |
| Active Comparator: Epigallocatechin-3-gallate (EGCG)<br>200 mg EGCG and same volume water as for tea beverage. | Dietary Supplement: EGCG<br> <br> |
| Placebo Comparator: Placebo (Water)<br>Same volume water as for all intervention arms. | Other: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Flow-mediated dilation of the arteria brachialis | Change in flow-mediated dilation (in %) of the arteria brachialis after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG is assessed by vascular ultrasound. | 2 hours after ingestion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Agonist-induced platelet aggregation in vitro | Blood is drawn two hours after consumption and the effects on in vitro agonist-induced platelet aggregation after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG are measured. | 2 hours after ingestion | 
| Determination of plasma tea polyphenol levels | Blood is drawn two hours after consumption and plasma concentrations of tea polyphenols are measured after a single dose of 200 mg EGCG either as green tea beverage, green tea extract or EGCG by HPLC. | 2 hours after ingestion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Green tea, EGCG, Cardiovascular diseases, Endothelial function, Flow-mediated dilation