Vitamin C improves endothelium-dependent vasodilation in forearm resistance vessels of humans with hypercholesterolemia

Henry H. Ting, Farris K. Timimi, Elizabeth A. Haley, Mary Anne Roddy, Peter Ganz, Mark A. Creager

Research output: Contribution to journalArticle

327 Scopus citations

Abstract

Background: Endothelium-dependent vasodilation is impaired in humans with hypercholesterolemia. Oxidative degradation of endothelium-derived nitric oxide plays a major role in endothelial dysfunction in animal models of hypercholesterolemia. To assess whether this mechanism is relevant to humans, we studied the effect of vitamin C, an antioxidant, on vasodilator function in forearm resistance vessels of patients with hypercholesterolemia. Methods and Results: We studied 11 hypercholesterolemic and 12 healthy control subjects. Forearm blood flow was deter mined by venous occlusion plethysmography. Endothelium-dependent vasodilation was assessed by intra- arterial infusion of methacholine (0.3 to 10 pg/min). Endothelium-independent vasodilation was measured by intra-arterial infusion of nitroprusside (0.3 to 10 μg/min) and verapamil (10 to 300 μg/min). Forearm blood flow dose- response curves were determined for each drug before and during coadministration of vitamin C (24 mg/min). In hypercholesterolemic subjects, endothelium-dependent vasodilation to methacholine was augmented by coinfusion of vitamin C (P=.001); in contrast, endothelium-independent vasodilation to nitroprusside and verapamil were not affected by coinfusion of vitamin C (P=.8 and P=.3, respectively). In control subjects, vitamin C administration did not alter endothelium-dependent vasodilation (P-.2). Conclusions: We conclude that vitamin C improves endothelium-dependent vasodilation in the forearm resistance vessels of patients with hypercholesterolemia. These findings suggest that nitric oxide degradation by oxygen-derived free radicals contributes to abnormal vascular reactivity in hypercholesterolemic humans.

Original languageEnglish (US)
Pages (from-to)2617-2622
Number of pages6
JournalCirculation
Volume95
Issue number12
DOIs
StatePublished - Jan 1 1997

Keywords

  • Antioxidants
  • Endothelium
  • Free radicals
  • Hypercholeslerolemia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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    Ting, H. H., Timimi, F. K., Haley, E. A., Roddy, M. A., Ganz, P., & Creager, M. A. (1997). Vitamin C improves endothelium-dependent vasodilation in forearm resistance vessels of humans with hypercholesterolemia. Circulation, 95(12), 2617-2622. https://doi.org/10.1161/01.CIR.95.12.2617