Eryptosis and oxidative damage in type 2 diabetic mellitus sedentary workers with chronic kidney disease

Introduction
It has been suggested that oxidative stress may participate in the progression of diabetes and its complications. Oxidative damage has been associated with erythrocyte apoptosis induction in other pathological conditions. Our aim was to study the presence of eryptosis and its possible relationship with oxidative damage in sedentary workers with T2DM without CKD (T2DM/CKD(-)) and in sedentary workers with T2DM and CKD (T2DM/CKD(+)).

Methods
The study was designed to determine the presence of eryptosis in T2DM sedentary workers with or without CKD (T2DM/CKD(+) and T2DM/ CKD(-)). In addition to this, we measured plasma total antioxidant capacity as well as oxidative damage, GSH/GSSG ratio, and osmotic fragility in erythrocytes of all groups and its possible association with the PS externalization in erythrocytes Data were analysed, using STATISTICA statistical software version 6.0.

Results
Oxidative damage of lipids erythrocytes were increased in sedentary workers. The highest lipoperoxidation was found in T2DM/CKD(+). Likewise, the lower plasma total antioxidant capacity, GSH/GSSG ratio, and GSH in erythrocytes were found in T2DM/CKD(+). A negative correlation was found between plasma total antioxidant capacity and oxidative damage. Phosphatidylserine (PS) externalization was measured in erythrocytes to evaluate eryptosis. The eryptosis in erythrocytes of T2DM/CKD(+) workers was higher than in healthy subjects and T2DM/CKD(-). A positive correlation between lipoperoxidation and PS externalization in erythrocytes was found.

Discussion
This study showed that the erythrocytes of diabetic sedentary workers have increased oxidative damage, a reduction of antioxidant systems and more erythrocyte PS externalization. The duration of diabetes and the presence of CKD increase both oxidative damage and eryptosis. It is possible that a longer time of evolution induces an increase in erythrocyte oxidative damage and the consumption of blood antioxidant systems, adding to the osmotic stress in CKD and so contributes to an increase in PS externalization in erythrocytes of diabetic sedentary workers.