Abstract 272: Vascular Reactivity During Insulin Infusion and Oral Glucose Challenge
Vascular rigidity predicts cardiovascular disease (CVD). Pulse wave velocity (PWV), reflecting vascular rigidity, though determined largely by mean arterial pressure; is also sensitive to insulin and glucose. Capacitance in small (C2) and large vessels (C1), reflecting vascular responsiveness to hemodynamic challenges, may also be influenced by insulin and glucose. The purpose of this study was to test the effects of insulin and glucose on arterial function in healthy people.
METHODS: Excluding people with BMI > 27.5 kg/m2, diabetes, impaired glucose tolerance, hypotension or hypertension, 14 adults were enrolled. Subjects underwent randomly either a 2 hour euglycemic clamping, or a 2-hr OGTT first, and the other a month later. Pulse wave velocity (PWV; carotid->dorsalis) and vascular compliance were measured by tonometry. Repeated measures ANOVA was used to compare parameter means over different time points.
Results: The sample (n=14) included 10 Caucasians, 8males, mean age=28.14+7.6 years, BMI=23.46+1.7kg/m2, SBP=112.79+8.6mmHg, DBP=69.57+6.1mmHg, and glucose=73+10.5mg/dl. There was a significant increase in mean PWV between 30 and 120 minutes (p=0.049), by euglycemic clamp (PWV change in OGTT was n.s.).
Conclusion: Insulin increased the PWV in clamp condition with minimal changes in C1 or C2. Oral glucose had less effect on PWV and again changes in C1 and C2 were minimal. These data support mechanisms that interweave insulin and arterial stiffness in vascular physiology and suggest that part of the mechanism of CVD in insulin resistance may relate to insulin’s effects on arterial rigidity.
- © 2012 by American Heart Association, Inc.