| Summary: | Background: Vascular stiffness predicts cardiovascular disease (CVD). Pulse wave velocity (PWV), reflecting vascular stiffness, 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 individuals.
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 h euglycemic clamping, or a 2-h OGTT first, with the other procedure performed up to one month later. Pulse wave velocity (PWV) and vascular compliance were measured by tonometry.
Results: The sample (n = 14) included 10 Caucasians, 8 males, mean age = 28 ± 8 years, BMI = 24 ± 2 kg/m2, SBP = 113 ± 9 mmHg, DBP = 70 ± 6 mmHg, and glucose = 73 ± 11 mg/dl. There was a significant increase in mean PWV between 30 and 120 min (p = 0.049), during the euglycemic clamp. PWV change during OGTT was not significant.
Conclusion: PWV increased during euglycemic clamp conditions without significant changes in C1 or C2. Oral glucose had less effect on PWV and changes in C1 and C2 were minimal. These data support mechanisms that link 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 stiffness.
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