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Diabetologia. 2010 May;53(5):989-1000. doi: 10.1007/s00125-010-1677-0. Epub 2010 Feb 26.

Hyperglycaemia-induced impairment of endothelium-dependent vasorelaxation in rat mesenteric arteries is mediated by intracellular methylglyoxal levels in a pathway dependent on oxidative stress.

Author information

1
Department of Internal Medicine, University Hospital Maastricht, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.

Abstract

AIMS/HYPOTHESIS:

Impaired nitric oxide (NO)-dependent vasorelaxation plays a key role in the development of diabetic vascular complications. We investigated the effect of hyperglycaemia on impaired vasoreactivity and a putative role therein of the AGE precursor methylglyoxal.

METHODS:

The effects of high glucose and methylglyoxal on NO-dependent vasorelaxation in isolated rat mesenteric arteries from wild-type and transgenic glyoxalase (GLO)-I (also known as GLO1) rats, i.e. the enzyme detoxifying methylglyoxal, were recorded in a wire myograph. AGE formation of the major methylglyoxal-adduct 5-hydro-5-methylimidazolone (MG-H1) was detected with an antibody against MG-H1 and quantified with ultra-performance liquid chromatography (tandem) mass spectrometry. Reactive oxygen species formation was measured with a 5-(and-6)-chloromethyl-2'7'-dichlorodihydrofluorescein diacetate acetyl ester probe and by immunohistochemistry with an antibody against nitrotyrosine.

RESULTS:

High glucose and methylglyoxal exposure of mesenteric arteries significantly reduced the efficacy of NO-dependent vasorelaxation (p < 0.05). This impairment was not observed in mesenteric arteries of GLO-I transgenic rats indicating a specific intracellular methylglyoxal effect. The diabetes-induced impaired potency (pD(2)) in mesenteric arteries of wild-type rats was significantly improved by GLO-I overexpression (p < 0.05). Methylglyoxal-modified albumin did not affect NO-dependent vasorelaxation, while under the same conditions the receptor for AGE ligand S100b did (p < 0.05). Methylglyoxal treatment of arteries increased intracellular staining of MG-H1 in endothelial cells and adventitia by fivefold accompanied by an eightfold increase in the oxidative stress marker nitrotyrosine. Antioxidant pre-incubation prevented methylglyoxal-induced impairment of vasoreactivity.

CONCLUSIONS/INTERPRETATION:

These data show that hyperglycaemia-induced impairment of endothelium-dependent vasorelaxation is mediated by increased intracellular methylglyoxal levels in a pathway dependent on oxidative stress.

PMID:
20186387
PMCID:
PMC2850524
DOI:
10.1007/s00125-010-1677-0
[Indexed for MEDLINE]
Free PMC Article
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