Oxidizing and reducing responses in type 1 diabetic patients determined up to 5 years after the clinical onset of the disease.

Oxidative stress has been suggested to be the mediator of hyperglycaemia-induced diabetic complications. For this study we asked whether a significant imbalance between oxidizing and plasmatic reducing responses could be observed in DM1 patients receiving intensive therapy up to 5 years following the clinical onset of the disease. A total of 16 type 1 diabetic patients (DM1) without complications and 13 non-diabetic subjects were enrolled. Clinical and biochemical parameters were compared in the two populations studied. Moreover, reactive oxygen species (ROS) generation by granulocytes and the total plasma antioxidant status were simultaneously evaluated. Granulocytes-ROS derived and plasma antioxidant status were determined by chemiluminescence assay and tetrazolium dye reduction, respectively. Type 1 diabetic patients were receiving intensive therapy by multiple daily injections. In comparison with healthy individuals, DM1 patients exhibited an increase in ROS generation whilst plasma antioxidant status was unaltered and appeared to be sufficient to prevent the onset of typical oxidative stress. The clinical characteristics and the remaining biochemical parameters studied were similar for the two groups, except for a significantly decreased plasmatic level of uric acid in DM1 patients. This study suggests that the absence of complications in DM1 patients up to 5 years after onset of the disease may be associated with the oxidizing and reducing balance which need to be maintained in order to prevent or delay the onset of oxidative stress. The effective diabetic control involves evaluation of the oxidizing/antioxidant balance besides glycaemic control.