RESUMEN
BACKGROUND: The aim of the present study was to examine the effect of aldehyde modification on antioxidant enzyme activity in diabetic patients. METHODS: The activity of commercially available antioxidant enzymes (catalase, glutathione peroxidase [GPx], and Cu,Zn-superoxide dismutase [SOD]) was determined in vitro prior to and after aldehyde modification. The activity of erythrocyte Cu,Zn-SOD was assayed in blood drawn from healthy donors, diabetic patients with decompensated carbohydrate metabolism, and diabetic patients after glucose-lowering therapy. RESULTS: In vitro aldehyde modification had no effect on catalase activity, but diminished GPx and Cu,Zn-SOD activity. In diabetic patients with decompensated carbohydrate metabolism, glucose-lowering therapy significantly increased Cu,Zn-SOD activity, the effect being especially pronounced after administration of metformin. CONCLUSIONS: It is likely that metformin antagonizes the aldehyde-induced inhibition of erythrocyte Cu,Zn-SOD in diabetic patients more effectively than sulfonylurea drugs.
Asunto(s)
Aldehídos/farmacología , Antioxidantes/química , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/enzimología , Eritrocitos/enzimología , Animales , Antioxidantes/metabolismo , Estudios de Casos y Controles , Bovinos , Diabetes Mellitus Tipo 2/sangre , Eritrocitos/efectos de los fármacos , Femenino , Glioxal/farmacología , Humanos , Hipoglucemiantes/uso terapéutico , Masculino , Malondialdehído/farmacología , Metformina/uso terapéutico , Persona de Mediana EdadRESUMEN
Under some pathological conditions, the natural dicarbonyl compounds can accumulate in the blood. The examples are malonyldialdehyde (MDA) formed as a secondary product of lipid peroxidation of unsaturated fatty acids during atherosclerosis, and glyoxal (GOX), a homolog of MDA, which accumulates during glucose autoxidation in patients with diabetes mellitus. This study compared the influence of both dicarbonyl compounds on low-density lipoproteins (LDL) and the membrane of endotheliocytes. In comparison with GOX, MDA induced more pronounced changes in physical and chemical properties of LDL particles. On the other hand, GOX-modified LDL particles were more prone to oxidation and aggregation than MDA-modified LDL. Incubation of endotheliocytes with MDA increased cell mechanical stiffness in contrast to incubation with GOX, which decreased it.
