Differential associations of circulating peroxiredoxins levels with indicators of glycemic control in type 2 diabetes mellitus

OBJECTIVES: Oxidative stress is an important patho-physiological mechanism in the development and complications of type 2 diabetes mellitus. To counteract oxidative stress the peroxiredoxin enzyme system exists in body cells. Whether diabetic state and/or glycemic control affects circulating levels of peroxiredoxins (PRDXs) needs to be elucidated. This study planned to assess PRDXs plasma levels of isoforms 1, 2, 4 and 6 in type 2 diabetes and their potential associations with glycemic control and insulin resistance. PATIENTS AND METHODS: Plasma/serum samples were obtained from type 2 diabetic patients (n=53, 28F/25M) and control non-diabetic subjects (n=25, 7F/18M). According to HbA1c diabetics were divided into well-controlled (HbA1c < 7, n=19) and poorly-controlled (HbA1c > 7, n=34). PRDXs isoforms and insulin were measured using ELISA. RESULTS: Compared to those of the control subjects, plasma levels of PRDXs1, 2, 4 and 6 were higher in diabetics. Poorly-controlled had lower levels of PRDXs2, 4 and 6 compared to well-controlled patients. PRDXs2 and 6 plasma levels negatively correlated with fasting blood sugar and HbA1c. No associations were detected with other isoforms and glycemic status or other parameters. CONCLUSIONS: The high levels of PRDXs in diabetes may suggest their chaperone function and their differential association with indicators of glycemic control may suggest their biomarker role and different mechanisms of action that warrants further investigations.