Role of AT1-receptor Blockers in Insulin-induced Vasodilation.

Study Overview
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Brief Summary
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In this study we hypothesize that blocking the angiotensin II AT1-receptor improves the insulin-induced microvascular dilatation. Objectives: 1. Does blockade of the angiotensin II AT1-receptor improve the insulin-induced microvascular effects in hypertensive patients. 2. Does blockade of the angiotensin II AT1-receptor impair the insulin-induced microvascular effects in normotensive control subjects?

Official Title
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Insulin-induced Microvascular Activity in Patients With Essential Hypertension: a Possible Role for Angiotensin II AT1-receptor Blockers.

Conditions
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Hypertension, Insulin Resistance, Microcirculation

Intervention / Treatment
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* Drug: Irbesartan
* Drug: Felodipine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: hypertensive subjects: 18-60 years Caucasian untreated hypertension >140/90mmHg. normotensive subjects: 18-60 years Caucasian Blood pressure <140/90 mmHg. Exclusion Criteria: Obesity (BMI>27kg/m2) Cardiovascular disease (stroke, coronary artery disease, peripheral vascular disease, heart failure) Impaired glucose tolerance or diabetes mellitus according to the criteria of the ADA Smoking Alcohol use >4U/day Use of medication (antihypertensive drugs, lipid lowering drugs, corticosteroids, NNSAIDs) Pregnancy Wearing contact lenses

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: I<br>Irbesartan | Drug: Irbesartan<br>* Single dose 600mg orally<br>* Other names: Aprovel C09CA04;|
| Active Comparator: II<br>Felodipine | Drug: Felodipine<br>* single dose 10mg Felodipine ER<br>* Other names: Plendil C08CA02;|
| Placebo Comparator: III<br>Placebo | Drug: Placebo<br>* Single dose tablet orally<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| functional recruitment of capillaries in the skin |  | July 2009 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| perfused capillary density in the nailfold |  | July 2009 | 
| Endothelium- (in)dependent vasodilatation of finger skin microcirculation |  | July 2009 | 
| Density of arterioles, capillaries and venules in the bulbar conjunctiva. |  | July 2009 | 
| Diameter of arterioles and venules in the bulbar conjunctiva |  | July 2009 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypertension, Insulin resistance, Microcirculation, Angiotensin II receptor blocker