This study will test the hypothesis that reduction in release of free fatty acids from adipocytes will restore insulin-mediated endothelium-dependent vasodilation and skeletal muscle glucose metabolism in subject with type 2 diabetes.
During the past two decades, there has been a steady increase in the incidence of diabetes mellitus, such that nearly 17 million people are now afflicted. The vast majority of these have type 2 diabetes. Over the next 40 years, the type 2 diabetic population in the United States is expected to increase to nearly 30 million. Diabetes substantially increases the risk of atherosclerosis, and thereby, cardiovascular morbidity and mortality. Indeed, cardiovascular disease causes more than 50% of the mortality in patients with diabetes. People with type 2 diabetes manifest two cardinal signs of dysmetabolism: hyperglycemia and insulin resistance. Insulin resistance is a progressive phenomenon that occurs well before the onset of frank diabetes, and results in alterations in insulin signaling. Experimental studies suggest that insulin signaling is required for vascular homeostasis, and its impairment is associated with endothelial dysfunction. In the clinical setting, insulin resistance is associated with atherosclerosis and predicts cardiovascular events independent of hyperglycemia. Therefore, we will study the importance of insulin signaling in endothelial biology in humans and the effects of free fatty acids on endothelial function in people with type 2 diabetes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
40
Brigham & Women's Hospital
Boston, Massachusetts, United States
Flow-mediated Dilation After Placebo or Acipimox Treatment Between Healthy Controls and Those With Metabolic Syndrome
Flow mediated dilation is calculated as follows: A resting arterial diameter measurement is obtained using the average of 10 EKG-gated ultrasound images. Next, an occlusive pressure is applied (using a blood pressure cuff inflated to a suprasystolic pressure)for a period of 5 minutes. After 5 minutes, the cuff is rapidly deflated. This produces a reactive hyperemic response which is captured via ultrasound at 1 minute post cuff deflation (also 10 EKG-gated images averaged). The diameter of the artery following reactive hyperemia is calculated and compared to the resting diameter to obtain a percent dilation. This is flow-mediated dilation.
Time frame: 7 days
Difference in Insulin-mediated Skeletal Muscle Glucose Utilization Between Test Agent and Placebo
Insulin sensitivity (M) is measured by using a hyperinsulinaemic-euglycaemic clamp. Insulin sensitivity (M) was calculated as the average glucose infusion rate (mg/kg of body weight per min) over the last 30 min of the clamp. Higher values indicate better outcomes (more insulin sensitive), while lower values indicate more insulin resistance.
Time frame: baseline, 7 days
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