Question: 

Free radicals, which are over-generated in type 2 diabetic patients, can have a negative effect on the structure and function of red blood cells. Peroxiredoxins (PRDX) are important antioxidative components. Therefore, we examined the influence of metabolic variables and physical fitness on oxidative stress and the peroxiredoxin system in the erythrocytes of type 2 diabetic men.

Methods: 

The extent to which oxidative stress (measured by 8-iso-prostaglandin-F2a (8-Iso-PGF) and overoxidized peroxiredoxins (PRDX-SO_2-3)) as well as the antioxidative protein isoform contents of PRDX1 and PRDX2 in the erythrocytes of type 2 diabetic men (n=22, age: 61±10 years) depend on BMI (mean: 32±4 kg/m², range: 26–40 kg/m²), HbA1c (mean: 6.6±1.1 %, range: 4.7–9.3 %) and VO_2peak (mean: 21±5 ml/min/kg, range: 10–28 ml/min/kg) was determined by regression analyses. The levels of 8-Iso-PGF, PRDX-SO_2-3, PRDX1 and PRDX2 at rest were quantified immunohistochemically.

Results: 

Statistical analyses showed significant sigmoidal correlations between HbA1c and 8-Iso-PGF as well as between VO_2peak and PRDX2 contents. Further significant correlations were not found.

Conclusions: 

The results indicate that poor glycemic control (HbA1c) negatively influences oxidative stress in the erythrocytes. Furthermore, cardio-respiratory fitness positively affects PRDX2 contents in the erythrocytes of type 2 diabetic patients.