Vitamin C Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin C, including details on benefits, dosage, supplements, information.

Telmisartan shows an equivalent effect of vitamin C in further improving endothelial dysfunction after glycemia normalization in type 1 diabetes.

Ceriello A, Piconi L, Esposito K, Giugliano D

Centre of Excellence in Diabetes and Endocrinology, University Hospital of Coventry and Warwickshire, Warwick Medical School, University of Warwick, Coventry, UK. antonio.ceriello@warwick.ac.uk

OBJECTIVE: Long-lasting hyperglycemia in type 1 diabetic patients induces permanent alterations of endothelial function by increased oxidative stress, even when glycemia is normalized. RESEARCH DESIGN AND METHODS: In this study, 36 type 1 diabetic patients and 12 control subjects were enrolled. The diabetic patients were divided into three groups. The first group was treated for 24 h with insulin, achieving a near normalization of glycemia. After 12 h of this treatment, vitamin C was added for the remaining 12 h. The second group was treated for 24 h with vitamin C. After 12 h of this treatment, insulin was started, achieving a near normalization of glycemia for the remaining 12 h. The third group was treated for 24 h with both vitamin C and insulin, achieving near normalization of glycemia. The same protocols were performed after 1 month of telmisartan or placebo. RESULTS: Neither normalization of glycemia nor vitamin C treatment alone was able to normalize endothelial dysfunction or oxidative stress. Combining insulin and vitamin C normalized endothelial dysfunction and decreased oxidative stress to normal levels. Telmisartan significantly improved basal endothelial function and decreased nitrotyrosine plasma levels. In patients treated with telmisartan, a near normalization of both flow-mediated vasodilation and oxidative stress was achieved when glycemia was normalized, whereas adding vitamin C infusion did not show further effect on endothelial function or nitrotyrosine plasma levels. CONCLUSIONS: These data indicate that combining the normalization of glycemia with an antioxidant can normalize endothelial function in type 1 diabetic patients and that telmisartan works as an antioxidant like vitamin C.

Published 28 June 2007 in Diabetes Care, 30(7): 1694-8.
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