Vitamin C further improves the protective effect of GLP-1 on the ischemia-reperfusion-like effect induced by hyperglycemia post-hypoglycemia in type 1 diabetes

Cardiovascular Diabetology (Impact Factor: 4.02). 06/2013; 12(1):97. DOI: 10.1186/1475-2840-12-97
Source: PubMed


It has been reported that hyperglycemia following hypoglycemia produces an ischemia-reperfusion-like effect in type 1 diabetes. In this study the possibility that GLP-1 has a protective effect on this phenomenon has been tested.
15 type 1 diabetic patients underwent to five experiments: a period of two hours of hypoglycemia followed by two hours of normo-glycemia or hyperglycemia with the concomitant infusion of GLP-1 or vitamin C or both. At baseline, after 2 and 4 hours, glycemia, plasma nitrotyrosine, plasma 8-iso prostaglandin F2alpha, sCAM-1a, IL-6 and flow mediated vasodilation were measured.
After 2 h of hypoglycemia, flow mediated vasodilation significantly decreased, while sICAM-1, 8-iso-PGF2a, nitrotyrosine and IL-6 significantly increased. While recovering with normoglycemia was accompanied by a significant improvement of endothelial dysfunction, oxidative stress and inflammation, a period of hyperglycemia after hypoglycemia worsens all these parameters. These effects were counterbalanced by GLP-1 and better by vitamin C, while the simultaneous infusion of both almost completely abolished the effect of hyperglycemia post hypoglycemia.
This study shows that GLP-1 infusion, during induced hyperglycemia post hypoglycemia, reduces the generation of oxidative stress and inflammation, improving the endothelial dysfunction, in type 1 diabetes. Furthermore, the data support that vitamin C and GLP-1 may have an additive protective effect in such condition.

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Available from: Loredana Bucciarelli, Jan 10, 2014
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    • "Uncoupling of eNOS is characterized by augmented tyrosine nitration which strongly indicates ONOO--triggered cellular injury in diabetic hyperglycemia [62]. Increased placental protein tyrosine nitration was documented in diabetic patients [63] and, in animal models of diabetes, 3NT was shown to be enhanced in the kidney [64] and in the ventricle and lens [65]. "
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