THE EFFECT OF HYPERGLYCEMIA ON THE VALUES OF ANTIOXIDATIVE PARAMETERS IN TYPE 2 DIABETIC PATIENTS WITH CARDIOVASCULAR COMPLICATIONS

Summary: Oxidative stress and hyperglycemia play an important role in the aethiology of vascular complications in diabetes. Hyperglycemia induces a large number of alterations in vascular tissue that potentially accelerate the atherosclerotic process. Nonenzymatic glycosylation of proteins and lipids which can interfere with their normal function by disrupting molecular conformation, alter enzymatic activity, reduce degradative capacity and interfere with receptor recognition, oxidative stress and protein kinase C activations are the major processes that encompass most of the pathological alterations in the diabetic vasculature. Diabetes-associated oxidative stress is a consequence of both increased production of free radicals and reduced capacity for antioxidative defense. The aim of this study was to test the parameters of antioxidative defense: superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and total antioxidant status (TAS), in type 2 diabetic patients with and without cardiovascular complications in order to determine the effect of hyperglycemia on the extent of disorders of antioxidative parameters. Sixty nine type 2 diabetic patients with cardiovascular complications, along with 48 diabetics without complications and 42 healthy subjects were examined. Determination of antioxidant parameters was performed using commercial tests manufactured by Randox Laboratories, UK, based on spectrophotometer determination methods. Statistical data processing revealed significantly lower SOD, GSH-Px, GR and TAS values in type 2 diabetic patients with cardiovascular complications in comparison to the control group (p<0.0001), as well as in comparison to diabetics without complications (p<0.01).