Erythrocyte susceptibility to oxidative stress and antioxidant status in patients with type 1 diabetes

In this study, malondialdehyde (MDA) level as an index of erythrocyte susceptibility to oxidative stress and antioxidant defense system (glutathione level (GSH), glutathione peroxidase enzyme activity (GPx) in erythrocytes and ferric reducing ability of plasma (FRAP) as the total plasma antioxidant capacity were measured in 35 patients with type 1 diabetes and 28 age and sex-matched normal subjects. MDA level was significantly elevated in diabetic patients (650.9 ± 144.3 nmol/g versus 476.5 ± 138.5 nmol/g Hb, P < 0.001). The level of MDA was positively correlated with duration of diabetes (r = 0.29, P < 0.05) and HbA1C (r = 0.39, P < 0.05) and negatively with FRAP (r = −0.3, P < 0.05). The level of GSH and FRAP were lower in patients than controls (7.05 ± 1.6 μmol/g versus 8.24 ± 0.9 μmol/g Hb, and 389.05 ± 82.3 μmol/l versus 520.4 ± 124.1 μmol/l, respectively, P < 0.001). GPx activity was not significantly different between the two groups. GSH and FRAP were negatively correlated with HbA1C (r = −0.334, P < 0.01 and r = −0.5, P < 0.01, respectively). In conclusion, there seems to be an increased susceptibility to oxidative stress and decreased antioxidant defense in patients with type 1 diabetes, which may be due to poor glycemic control.