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

O. Brouwers, P. M. Niessen, G. Haenen, T. Miyata, M. Brownlee, C. D. Stehouwer, J. G. De Mey, C. G. Schalkwijk

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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 (pD2) 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.

Original languageEnglish (US)
Pages (from-to)989-1000
Number of pages12
JournalDiabetologia
Volume53
Issue number5
DOIs
StatePublished - May 1 2010

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Keywords

  • AGE
  • Endothelium
  • Glycation
  • Microvascular disease
  • Oxidative stress
  • Rat

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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