1,5-Anhydroglucitol Attenuates Cytokine Release and Protects Mice with Type 2 Diabetes from Inflammatory Reactions

Abstract

1,5-anhydroglucitol (1,5-AG) decreases in diabetic patients and is used as a marker of glycemic control. Type 2 diabetic patients are susceptibile to lipopolysaccharides (LPS), which stimulate macrophages to release large quantities of tumor necrosis factor (TNF)-α and interleukin (IL)-6. This study examines the effects of 1,5-AG on lung inflammation induced by LPS and consequent systemic inflammation to determine whether the decrease of 1,5-AG concentration induces susceptibility to LPS. Before the challenge with LPS (1 mg/kg in vivo and 500 ng/ml in vitro), we pretreated db/db mice and RAW264.7 cells with 1,5-AG at 38.5 mg/kg and 500 μg/ml, respectively. The levels of IL-6, TNF-α, macrophage chemoattractant protein (MCP)-1 and IL-1β in the serum and in the cell supernatants were measured. We also measured macrophage recruitment and the expression of inducible nitric oxide synthase (iNOS) in pulmonary tissues. We found that 1,5-AG attenuated serum cytokine release and protected db/db mice from LPS-induced pulmonary inflammation. In addition, 1,5-AG suppressed cytokine release and iNOS expression by suppressing Akt/NF-κB activity in RAW264.7 cells. These results suggest that 1,5-AG may be a mediator in, as well as marker for diabetes, and 1,5-AG intake may confer tolerance to LPS in patients with type 2 diabetes.