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Antioxidant vitamins C and E ameliorate hyperglycaemia‐induced oxidative stress in coronary endothelial cells
Author(s) -
Ülker S.,
McMaster D.,
McKeown P. P.,
Bayraktutan U.
Publication year - 2004
Publication title -
diabetes, obesity and metabolism
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.445
H-Index - 128
eISSN - 1463-1326
pISSN - 1462-8902
DOI - 10.1111/j.1462-8902.2004.00443.x
Subject(s) - oxidative stress , antioxidant , chemistry , superoxide dismutase , catalase , biochemistry , mannitol , nitric oxide , glutathione peroxidase , ascorbic acid , endocrinology , pharmacology , medicine , biology , food science , organic chemistry
Objective: Vitamins C and E have protective features in many disease states associated with enhanced oxidative stress. The aim of this study was to investigate whether vitamin(s) C and/or E modulate hyperglycaemia‐induced oxidative stress by regulating enzymatic activities of prooxidant, i.e. NAD(P)H oxidase and/or antioxidant enzymes, namely endothelial nitric oxide synthase (eNOS), superoxide dismutase, catalase and glutathione peroxidase, using coronary microvascular endothelial cells (CMEC). Methods: CMEC were cultured under normal (5.5 m m ) or high glucose (22 m m ) concentrations for 7 days. The enzyme activities were determined by specific assays. The levels of O 2 – and nitrite were measured by cytochrome c reduction and Griess assays respectively. Results: Hyperglycaemia did not alter eNOS activity or overall nitrite generation, an index of NO production. However, it increased NAD(P)H oxidase and antioxidant enzyme activities (p < 0.05). Specific inhibitors of NAD(P)H oxidase, i.e. phenylarsine oxide (0.1–3 µ m ) and 4‐(2‐aminoethyl)benzenesulfonyl fluoride (5–100 µ m ) and vitamins C and E (0.1–1 µ m ) significantly reduced prooxidant and antioxidant enzyme activities in CMEC exposed to hyperglycaemia (p < 0.01). The differences in enzyme activities were independent of increases in osmolarity generated by high glucose levels as investigated by using equimolar concentrations of mannitol in parallel experiments. Conclusions: Vitamins C and E may protect CMEC against hyperglycaemia‐induced oxidative stress by concomitantly regulating prooxidant and antioxidant enzyme activities.