Document Detail

Pretreatment with intravenous ascorbic acid preserves endothelial function during acute hyperglycaemia (R1).
MedLine Citation:
PMID:  15854139     Owner:  NLM     Status:  MEDLINE    
1. Acute hyperglycaemia may impair endothelial function. Ascorbic acid (AA), administered intra-arterially, has been reported to improve endothelium-dependent vasodilatation during a forearm hyperglycaemic clamp. Using a randomized, double-blind, placebo-controlled, cross-over study, we investigated the potential for intravenous ascorbic acid to modify the endothelial response to acute systemic hyperglycaemia in humans. 2. Nine healthy male volunteers were recruited from the hospital staff. Endothelial function was determined by measuring the forearm blood flow responses to intrabrachial infusions of endothelium-dependent (ED) and endothelium-independent (EID) vasodilators. The endothelial function index (EFI) was derived from the ratio of ED and EID vasodilatation. Haemodynamic and endothelial function measurements were performed at baseline and then repeated 2 h after a systemic hyperglycaemic clamp (14 mmol/L). The subjects, studied on two separate occasions, were randomized to placebo or 2 g intravenous ascorbic acid prior to the initiation of hyperglycaemia. 3. After systemic hyperglycaemia with placebo pretreatment, the EFI fell from 1.08 +/- 0.21 to 0.74 +/- 0.13 (difference (95% confidence interval): 0.34 (0.20, 0.47); P < 0.001). When subjects were pretreated with ascorbic acid, the EFI was not affected by hyperglycaemia (1.11 +/- 0.21 to 1.12 +/- 0.17; P = 0.938). This difference between placebo and ascorbic acid was significant (P < 0.001). Plasma ascorbate concentrations decreased during hyperglycaemia and correlated directly with the reduction in the EFI (r = 0.798; P < 0.001). 4. Pretreatment with an intravenous bolus of ascorbic acid can prevent endothelial dysfunction during acute systemic hyperglycaemia. Therefore, ascorbic acid may have potential therapeutic use in clinical situations where acute hyperglycaemia may be a complication.
Brian A Mullan; Ciaran N Ennis; Howard J P Fee; Ian S Young; David R McCance
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Publication Detail:
Type:  Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  32     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:    2005 May-Jun
Date Detail:
Created Date:  2005-04-27     Completed Date:  2006-01-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  340-5     Citation Subset:  IM    
Department of Anaesthesia and Intensive Care Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK.
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MeSH Terms
Acute Disease
Analysis of Variance
Ascorbic Acid / administration & dosage*
Cross-Over Studies
Dose-Response Relationship, Drug
Double-Blind Method
Endothelium, Vascular / drug effects*,  physiology
Hyperglycemia / drug therapy*,  physiopathology
Infusions, Intravenous
Reg. No./Substance:
50-81-7/Ascorbic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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