title: Relation of plasma insulin levels to forearm flow-mediated dilatation in healthy volunteers.
abstract: Although several observations suggest that insulin resistance/compensatory hyperinsulinemia (IR/CH) has a direct effect on endothelial function, independently of the metabolic abnormalities associated with the defect in insulin action, this relation has not been evaluated in apparently healthy individuals. To address this issue, we measured endothelial-dependent vasodilation in response to forearm ischemia (flow-mediated dilation [FMD]) in 47 nonsmoking, healthy volunteers without known risk factors for atherosclerosis. Measurements were also made of multiple anthropometric, metabolic, and hemodynamic variables related to IR/CH. Decreases in FMD were significantly correlated (analysis of variance for linear trend) with (1) male gender (p = 0.003), (2) waist circumference (p = 0.038), (3) higher fasting plasma insulin (p = 0.015) and triglyceride concentrations (p = 0.023), and (4) lower concentrations of high-density lipoprotein cholesterol (p = 0.001). Multivariate linear regression analysis indicated that only plasma insulin (beta -0.424) was independently associated (p <0.001) with changes in FMD, and individual differences in insulin concentrations, along with gender and brachial artery diameter at baseline, accounted for approximately 39% of the variability in FMD. In conclusion, IR/CH is an independent predictor of decreases in endothelial-dependent vasodilation in apparently healthy individuals, in the absence of traditional risk factors for atherosclerosis.
authors.affiliation: Department of Internal Medicine and Biomedical Sciences, Parma University, Parma, Italy. d.ardigo@libero.it
authors.forename: Diego
authors.initials: D
authors.lastname: Ardigo
authors.forename: Laura
authors.initials: L
authors.lastname: Franzini
authors.forename: Silvia
authors.initials: S
authors.lastname: Valtuena
authors.forename: Lucilla D
authors.initials: LD
authors.lastname: Monti
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Reaven
authors.forename: Ivana
authors.initials: I
authors.lastname: Zavaroni
mesh_terms: D000368:Aged; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology; D008076:Cholesterol, HDL / Q000097:blood; D004730:Endothelium, Vascular / Q000502:physiology; D005215:Fasting; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007328:Insulin / Q000097:blood*; D007511:Ischemia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology*; D049629:Waist-Hip Ratio
chemical_list: D008076:Cholesterol, HDL; D007328:Insulin; D014280:Triglycerides