Summary
Background: Both endothelial cell function and autonomic function are infl uenced by age. However, the interrelationships between the 2 have not been carefully examined. Material and Methods: Thirty nondiabetic control subjects (C) and 25 subjects with type 2 diabetes (D) participated. Endothelial cell function was assessed by 4 minutes of occlusion of the brachial artery followed by measurement of blood
fl ow (BF) immediately post occlusion. To assess autonomic reactivity, subjects were exposed to a 32oC room for 30 minutes and a tilt table elevated subjects from the horizontal to the 45 degree head up
position. A laser Doppler fl ow imager was used to assess skin fl ows during the tilting phase.
Results: For endothelial function, the average BF of C increased 2.24±0.64 cc/100 gm tissue/minute at rest to 26.8±4.9 cc/100 gm tissue per minute post occlusion. D subjects had resting BF of 0.8 cc/100 gm tissue per minute with an increase to an average of 8.1±3.64 cc/100gm tissue per minute post occlusion. In both, aging was associated with lower resting and post occlusion BF. However, D had lower BF than the controls. For D, both the resting fl ows and reduction in fl ows during tilting were less than the controls. Both groups followed a parallel decrease in fl ow with aging. Autonomic reactivity (ratio of BF to the skin in the vertical to horizontal posture) was 0.4±0.27 for the controls and 0.72±0.09 for the subjects with diabetes.
Conclusions: The data suggests that diabetes alters both the endothelial and autonomic function.

Keywords: Diabetes Mellitus, Type 2 - immunology, Aging - physiology, Autoimmunity, Blood Flow Velocity, Blood Pressure, Diabetes Mellitus, Type 2 - physiopathology, Endothelium, Vascular - physiopathology, Forearm - physiopathology, Posture, Reference Values, Regression Analysis, Skin - blood supply