Hyperreactivity to Nitrovasodilators in Forearm Vasculature Is Related to Autonomic Dysfunction in Insulin-Dependent Diabetes Mellitus

Background The link between diabetes and vascular disease is poorly understood. Data regarding endothelial function in vivo in patients with insulin-dependent diabetes mellitus (IDDM) have been inconsistent with in vitro studies demonstrating hyperglycemia-induced impairments in endothelium-dependent vasodilation. Methods and Results We determined whether alterations in neural control of the vascular tone might contribute to blood flow responses to intrabrachial infusions of acetylcholine (ACh), sodium nitroprusside (SNP), and l-N-monomethyl-arginine (L-NMMA) in 22 men with IDDM (12 with normoalbuminuria, HbA1c=8.6±0.3%; 10 with macroalbuminuria, HbA1c=8.6±0.3%) and 11 matched normal men. Autonomic function was assessed from reflex vasoconstriction to cold, the blood pressure response to standing and hand grip, and heart rate variation, including spectral analysis, during controlled breathing, and the Valsalva maneuver. IDDM with macroalbuminuria exhibited hyperresponsiveness to both ACh and SNP compared ...