Effect of Metformin on Insulin Sensitivity and Pan-Arterial Vascular Function in Adults With Metabolic Syndrome

University of Virginia19 enrolled

Overview

The purpose of this study is to look at how insulin (a hormone that helps the cells get energy from sugar) in our body affects blood vessels (elasticity in the bigger blood vessels and blood flow in the smaller blood vessels in the arm) and how Metformin (a drug that makes you more sensitive to insulin) affects insulin's action on the blood vessels.

In our protocol, we will study vascular function using pulse wave velocity (PWV) augmentation index (AI), flow mediated dilation (FMD) and contrast enhanced ultrasound (CEU) as well as insulin sensitivity (euglycemic clamp) in 50 adults with metabolic syndrome, age 18-60 years. They will each be studied 4 times,before and after two 12-wk interventions (randomly assigned) as follows: 1) Placebos and 2) Metformin . This is a cross-over design.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Metabolic Syndrome Insulin Sensitivity

Interventions

PlacebosDRUG

A 12 week single blind placebos

metforminDRUG

A 12 week single blind metformin

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age 18-60 * No smoking the past 6 months * Normal screening labs or no clinically significant values-except those listed below * Must have 3 of the following 4 characteristics established by NCEP-AHA-NHLBI * Males waist circumference greater than 40 inches, females greater than 35 inches * Blood pressure greater than 130/85 or on treatment with one or more antihypertensive agent * Fasting plasma triglycerides \>150 or HDL \<40 (males) \<50 (females) * Fasting blood sugar \>100 but \<126 * Subject may participate if on the following drugs, provided the drugs can remain at stable doses throughout the 12 week treatment interval. * Ace inhibitor * ARB * HMG CoA reductase inhibitor * Beta blocker * Calcium channel blockers * Alpha-adrenergic antagonist Exclusion Criteria: * Smoking presently or in the past 6 months * HbA1c ≥ 6.5 * Glucocorticoids-eg: prednisone, dexamethasone * Any known sensitivity or intolerance to Metformin * Any chronic GI disorders such as Irritable Bowel Syndrome or Crohns disease * History of congestive heart failure, ischemic heart disease, severe pulmonary disease, liver or kidney disease. * History of malignant or metabolic disorders including diabetes * Presence of an intracardiac or intrapulmonary shunt (we will screen for this by auscultation during the physical exam by PI) * Hypersensitivity to perflutren (contained in Definity) * Pregnant or breastfeeding

Locations (1)

University of Virginia

Charlottesville, Virginia, United States

Outcomes

Primary Outcomes

Flow Mediated Dilation - Endothelial Function

brachial artery ultrasonography % flow-mediated dilatation (FMD) for assessing endothelial function before and after an insulin clamp to assess insulin's effect on the vasculature

Time frame: before and after 12 weeks on placebo or metformin

Data from ClinicalTrials.gov

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