title: Acute and chronic effects of vitamin C on endothelial fibrinolytic function in overweight and obese adult humans.
abstract: We determined the effects of acute intra-arterial vitamin C administration and chronic oral vitamin C supplementation on the capacity of the endothelium to release t-PA in overweight and obese adults. Net endothelial t-PA release was determined in vivo in response to intrabrachial infusions of bradykinin and sodium nitroprusside in 33 sedentary adults: 10 normal-weight (BMI: 23.4 +/- 0.5 kg m(-2); 7M/3F); and 23 overweight/obese (BMI: 31.2 +/- 0.8 kg m(-2); 15M/8F). In 10 normal weight and eight overweight/obese adults the dose-response curves to bradykinin and sodium nitroprusside were repeated with a coinfusion of the antioxidant vitamin C (24 mg min(-1)). Seventeen of the 23 overweight/obese adults completed a 3 month chronic oral vitamin C (500 mg day(-1)) supplementation intervention. Intra-arterial administration of vitamin C significantly potentiated t-PA release in overweight/obese adults. Net release of t-PA was approximately 95% higher (P < 0.01) after (from -0.9 +/- 1.1 to 94.6 +/- 16.2 ng (100 ml tissue)(-1) min(-1)) compared with before (from -0.8 +/- 0.8 to 49.9 +/- 7.7 ng (100 ml tissue)(-1) min(-1)) vitamin C administration. Daily vitamin C supplementation significantly increased t-PA release in overweight/obese adults (from 0.2 +/- 0.9 to 48.2 +/- 6.5 ng (100 ml tissue)(-1) min(-1)) before supplementation versus (0.3 +/- 0.5 to 66.3 +/- 8.7 ng (100 ml tissue)(-1) min(-1)) after supplementation. These results indicate that the antioxidant vitamin C favourably affects the capacity of the endothelium to release t-PA in overweight/obese adults. Daily vitamin C supplementation represents an effective lifestyle intervention strategy for improving endothelial fibrinolytic regulation in this at-risk population.
authors.affiliation: Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, 354 UCB, Boulder, CO 80309, USA.
authors.forename: Gary P
authors.initials: GP
authors.lastname: Van Guilder
authors.forename: Greta L
authors.initials: GL
authors.lastname: Hoetzer
authors.forename: Jared J
authors.initials: JJ
authors.lastname: Greiner
authors.forename: Brian L
authors.initials: BL
authors.lastname: Stauffer
authors.forename: Christopher A
authors.initials: CA
authors.lastname: DeSouza
mesh_terms: D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000494:pharmacology*; D001920:Bradykinin / Q000494:pharmacology; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D004334:Drug Administration Schedule; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D005342:Fibrinolysis / Q000187:drug effects*; D006801:Humans; D007261:Infusions, Intra-Arterial; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology; D050177:Overweight; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D014665:Vasodilator Agents; D009599:Nitroprusside; D001205:Ascorbic Acid; D001920:Bradykinin