Objectives: There is strong evidence that oxidative stress caused by metabolic changes due to insulin resistance contribute to the complications of metabolic syndrome. The decreased activities of Paraoxonase (PON1), an antioxidant enzyme closely associated with high-density lipoprotein (HDL), has been shown to be related with dyslipidemia, diabetes mellitus, advanced age, hypertension, low HDL and increased oxidative stress. The aim of this study is to investigate the relation between serum PON1 activity levels and metabolic syndrome diagnostic criteria and to examine whether PON1 activity changes is a part of metabolic syndrome or not.

Material and Methods: Forty-five metabolic syndrome patients diagnosed in Fırat Clinical Medicine Center Endocrinology Clinics and forty-five healty control subjects were included into the study. Serum levels of PON1 and ARE activities and total cholesterol, triglyceride, low density lipoprotein (LDL), high density lipoprotein (HDL), very low density lipoprotein (VLDL), glucose, insulin, uric acid, C-peptid, aspartat aminotransferase (AST), alanin aminotransferase (ALT), gamma glutamyl transferase (GGT), hemoglobin (Hb), hematocrite (Hct), platelet (PLT) were measured.

Results: Serum PON1 activity levels were found to be significantly lower (p<0.05), and lipid concentrations were significantly higher in subjects with metabolic syndrome compared with unaffected subjects (p<0.05). Serum glucose, total cholesterol, LDL, VLDL, triglyceride, GGT, insulin, C-peptid, homeostasis model assessment (HOMA), body mass index (BMI), systolic blood pressure and waist circumference were found to be significantly higher, and HDL levels was significantly lower, in subjects with metabolic syndrome compared with unaffected subjects (p<0.05).

Conclusion: In summary, lower antioxidant PON1 enzyme activity, increased lipid levels, low HDL and increased glucose levels in patients with metabolic syndrome can suggest that PON1 can hold an important place in the medical treatment and early diagnosis with further studies in subjects with metabolic syndrome.©2008, Firat University, Medical Faculty.