Nitric Oxide-Dependent Regulation of Cytokines Release in Type-II Diabetes Mellitus

The mechanism of release of proinflammatory cytokines by blood granulocytes in diabetes is unknown. We investigated whether diabetes mellitus affects the production of cytokines by granulocytes (PMN) and mononuclear cells (PBMCs) and whether this is modulated by NO. Isolated PMN and PBMC from with or without type-II diabetes mellitus were incubated at 37°C for 6 h with S-nitroso-N-acetylpenicillamine (SNAP) at 0, 1, and 100  μ M with or without lipopolysaccharides (LPS) stimulation (1  μ g/mL). Supernatants were assayed for tumor necrosis factor- α (TNF- α ) and interleukin-8 (IL-8) by sandwich ELISA. Significant increases in TNF- α and IL-8 were observed only in PMN from diabetic subjects with or without LPS stimulation and that exogenous NO inhibited further production of cytokines in a concentration-dependent manner. However, activity of PBMC when stimulated with LPS was greatly enhanced by diabetes, but not affected by NO production. Hence, suggesting that granulocytes activation and participation in diabetes related complications is modulated by NO bioavailability.