Thiols, Malonaldehyde and Total Antioxidant Status in the Turkish Patients with Type 2 Diabetes Mellitus

Thiols, Malonaldehyde and Total Antioxidant Status in the Turkish Patients with Type 2 Diabetes Mellitus

BELGIN SÜSLEYICI DUMAN, MELEK ÖZTÜRK,¹ SELMA YILMAZER¹ and HÜSREV HATEMI^{2, 3}

Department of Medical Biology and Genetics, Kadir Has University Faculty of Medicine, Istanbul, Turkey, ¹Department of Medical Biology, Istanbul University Cerrahpasa Faculty of Medicine, Istanbul, Turkey, ²Turkish Diabetes Hospital, Istanbul, Turkey, and ³Department of Endocrinology and Metabolism, Istanbul University, Cerrahpasa Faculty of Medicine, Istanbul, Turkey

Non-insulin-dependent (Type 2) diabetes mellitus (NIDDM) is a risk factor for cardiovascular diseases (CVD). Oxidative stress mechanisms are often reported to be implied in type 2 diabetes mellitus. In order to determine their clinical relevance, we investigated several plasma indicators in the Turkish patients with NIDDM: (i) homocysteine (Hcy) and cysteine (Cys) which contribute to increase the risk of atherosclerosis during NIDDM, (ii) glutathione (GSH) and cysteinylglycine (CysGly) resulting from GSH degradation catalyzed by γ-glutamylcysteine transferase (GGT), (iii) malonaldehyde (MDA) as a marker for lipid peroxidation, and (iv) total antioxidant status (TAS). Our main results were evaluated based on sex and diabetic status. In female patients, plasma concentrations of MDA and Hcy were significantly higher than in controls, while GSH levels were significantly lower. In males, a difference between control and diabetic groups was noticed only for Hcy, levels being also higher in patients. In the diabetic group, increase in serum glucose concentration was significantly correlated with increased GGT activity. In both controls and diabetic patients, GGT activity was correlated with a raised Cys concentration and a decreased GSH level. In both controls and diabetic patients, there were significant positive correlations between Cys and Hcy and between GSH and Hcy. We concluded that GSH and MDA levels are clinical indicators for an oxidative process linked to type 2 diabetes mellitus, especially in women.

keywords —— NIDDM; oxidative stress; lipid peroxidation; sex

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Tohoku J. Exp. Med., 2003, 201, 147-155

Address for reprints: Dr. Belgin Süsleyici Duman, Department of Medical Biology and Genetics, Kadir Has University Faculty of Medicine, Vefabey Street, No:5 80810, Gayrettepe-Istanbul, Turkey.

e-mail: bsusleyici@khas.edu.tr