Protein oxidation markers in women with and without gestational diabetes mellitus: A possible relation with paraoxonase activity

Aims: To clarify the levels of protein oxidation markers such as protein carbonyl (PCO), protein hydroperoxides (P-OOH), advanced oxidation protein products (AOPP) and nitrotyrosine (NT), as well as antioxidative enzymes such as paraoxonase (PON-1) in women with and without gestational diabetes mellitus (GDM). Methods: The study was conducted on 23 women with GDM and 22 women without GDM. The levels of the P-OOH, AOPP, and PON-1 were determined by colorimetric methods; whereas NT and PCO levels were measured by ELISA. Results: The concentrations of protein oxidation markers were significantly increased and PON1 activity was significantly decreased in GDM group compared to those of normal pregnant women. The control group showed a significant negative correlation between PON-1 and PCO (r = -0.451, p = 0.027); whereas in GDM group, there was a significant positive correlation between P-OOH and HbA1c (r = 0.89, p = 0.001). There was no significant correlation between AOPP, PON-1, P-OOH, PCO, and HbA1c in either group. Conclusions: There is evidence of a possible association between protein oxidation and decreased PON1 activity in GDM. The increase in protein oxidation parameters in the GDM group leading to decreased PON1 activity might, we think, create a predisposition for clinical complications in GDM group. (C) 2011 Elsevier Ireland Ltd. All rights reserved.