The relationship between serum level of leptin and oxidative stress in patients with hyperglycemia crisis

Abstract

To investigate the relationship between the levels of serum leptin and oxidative stress in patients with hyperglycemia crisis. A total of 96 patients with diabetic ketoacidosis (DKA) and nonketotic hyperglycemia (NKH) were treated on a low-dose insulin protocol using intravenous infusion of insulin with the established rate of 0.1 Uxkg(-1)xh(-1), with the patients on intravenous fluids and receiving nutrition by mouth and vein. The levels of serum leptin, 8-iso-prostaglandin F(2 alpha) (8-iso-PGF(2 alpha)), the activities of superoxide dismutase (SOD), total antioxidant capacity (TAC) and the contents of malondialdehyde (MDA) in 96 patients with hyperglycemia crisis on admission and after insulin therapy with resolution of hyperglycemia and ketoacidosis (72 hours) were measured. Another 35 healthy individuals served as normal control. The activities of SOD, TAC and the levels of leptin before treatment were lower in patients with hyperglycemia crisis than in normal controls, and the levels of MDA and 8-iso-PGF(2 alpha) were more markedly elevated than those in normal controls (all P<0.05). The activities of SOD, TAC and the levels of leptin in patients after treatment were significantly higher than those in patients before treatment, and the levels of MDA and 8-iso-PGF(2 alpha) were significantly lower than those in patients on admission (all P<0.05). There was significant positive correlation between leptin and MDA in patients before treatment (r=0.38, P<0.05), and the level of leptin was negatively correlated with MDA and 8-iso-PGF(2 alpha) in patients after treatment (r(1)=-0.35, r(2)=-0.37, both P<0.05). In stepwise regression analysis, MDA and 8-iso-PGF(2 alpha) showed a significant association with leptin. The levels of leptin are significantly lowered in patients with hyperglycemia crisis. Oxidative stress may participate in determining the leptin level in hyperglycemia crisis.