Microvascular Dilatation After Endogenous Induced Hyperinsulinemia

Study Overview
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Brief Summary
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In this study we will examine if the insulin-induced microvascular effects will occur after a physiological stimulus (i.e. a oral glucose tolerance test). With that the physiological importance of the insulin-induced microvascular dilatation can be elucidated. In this study we hypothesize that oral glucose intake and consequently the endogenous induced hyperinsulinemia will lead to insulin-induced microvascular dilatation in healthy normotensive subjects. Furthermore, we suggest that the insulin-mediated microvascular dilatation, resulting from this physiological induced hyperinsulinemia, will be less in hypertensive and obese subjects compared to healthy controls.

Official Title
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Insulin-induced Microvascular Dilatation During a Physiological Stimulus - Studies in Hypertension and Obesity.

Conditions
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Hypertension, Obesity

Intervention / Treatment
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* Dietary Supplement: Glucose solution
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy normotensive subjects: 18-60 years Caucasian Blood pressure <140/90 mmHg obese normotensive subjects: 18-60 years Caucasian Blood pressure <140/90 mmHg BMI 30-38kg/m2 hypertensive subjects: 18-60 years Caucasian Untreated hypertension >140/90mmHg. Exclusion Criteria for healthy normotensive and hypertensive subjects: Obesity (BMI>27kg/m2) Cardiovascular disease (stroke, coronary artery disease, peripheral vascular disease, heart failure) 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 for normotensive obese subjects: 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: I<br>Glucose | Dietary Supplement: Glucose solution<br>* single oral intake of 250 ml glucose solution (75gr sugar in 250ml of water)<br>|
| Placebo Comparator: II<br>Placebo | Dietary Supplement: Placebo<br>* single intake of placebo solution (250ml of sweet flavored water, no sugar added), 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. |  | January 2009 - January 2010 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Perfused capillary density in the nailfold. |  | January 2009 - January 2010 | 
| Endothelium- (in)dependent vasodilatation of finger skin microcirculation |  | January 2009 - January 2010 | 
| Density of arterioles, capillaries and venules in the bulbar conjunctiva. |  | January 2009 - January 2010 | 
| Diameter of arterioles and venules in the bulbar conjunctiva. |  | January 2009 - January 2010 | 
| Insulin sensitivity (HOMA-IR) |  | January 2009 - January 2010 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Microcirculation, Insulin, Hypertension, Obesity