Effect of Hyperglycemia on Microvascular Perfusion in Healthy Adults

Effect of Hyperglycemia on Microvascular Perfusion in Healthy Adults

The investigators are studying the effects of Hyperglycemia on vascular function and insulin sensitivity on healthy adults

The investigators will study 22 healthy subjects (18-35 yrs) four times as follows:

1. Saline + Octreotide + euglycemia;
2. Octreotide + hyperglycemia;
3. Octreotide + hyperglycemia + insulin clamp and
4. Octreotide + Euglycemia + insulin clamp.

The sequence of admissions will be assigned randomly. The investigators will assess function in conduit (pulse wave velocity-PWV, augmentation index-AI and flow-mediated dilation-FMD), resistance (post-ischemic flow velocity-PIFV) and heart and skeletal muscle microvascular (contrast enhanced ultrasound-CEU) vessels.

This work will:

a) identify whether vascular stiffness and indices of NO action are impaired throughout the arterial tree with hyperglycemia.

Inclusion Criteria:

• Healthy with no chronic illness
• Age 18-35
• Normal BMI (18-25)
• Normal screening labs or no clinically significant values

Exclusion Criteria:

• First degree relative with Type 2 Diabetes
• Smoking presently or in the past 6 months
• Medications that affect the vasculature
• Overweight or other indications of insulin resistance
• Elevated LDL cholesterol > 160
• Elevated BP > 140/90
• History of congestive heart failure, ischemic heart disease, severe pulmonary disease, liver or kidney disease, bleeding disorders
• Any vascular disease such as myocardial infarction, stroke, peripheral vascular disease
• Presence of an intracardiac or intrapulmonary shunt (we will screen for this by auscultation during the physical exam by PI).
• Pregnant or breastfeeding.
• Known hypersensitivity to perflutren (contained in Definity)