Considering the involvement of the innate immune system, in association with the role of HMGB1 as an activator of TLR and RAGE, diabetes should be considered and treated as a metabolic and immunological disease, triggered by hyperglycemia. HMGB1 plays a central role in mediating injury and inflammation, and interactions involving HMGB1-TLR-RAGE constitute a tripod that trigger NF-κB activation. Blockade or downregulation of HMGB1, and/or control of the inflammatory tripod, represent a promising therapeutic approach for the treatment of diabetes.

No abstract

The antioxidant vitamin complex was effective in reducing oxidative stress in PBMNC of AD patients by lowering ROS production, improving cellular antioxidant capacities and modifying cytokine induced inflammation.

O diabetes melito e suas complicações apresentam origem multifatorial. Mecanismos bioquímicos e patológicos estão associados com hiperglicemia crônica no diabetes e o aumento do estresse oxidativo tem sido postulado com papel central nestas desordens. Evidências sugerem que a lesão celular oxidativa causada pelos radicais livres contribuem para o desenvolvimento das complicações no diabetes tipo 1 (DM1) e a diminuição das defesas antioxidantes (enzimáticas e não-enzimáticas) parecem correlacionar-se com a gravidade das alterações patológicas no DM1. Nesta revisão, relata-se como o estresse oxidativo pode exercer efeitos deletérios no diabetes e são apresentadas as opções terapêuticas em estudo para modulação da injúria vascular.

We examined nitric oxide (NO), IL-6, and TNF-α secretion from cultured palmitate-stimulated PBMNCs or in the plasma from type 2 diabetes mellitus (T2MD) patients or nondiabetic (ND) controls. Free fatty acids (FFA) have been suggested to induce chronic low-grade inflammation, activate the innate immune system, and cause deleterious effects on vascular cells and other tissues through inflammatory processes. The levels of NO, IL-6, TNF-α, and MDA were higher in supernatant of palmitate stimulated blood cells (PBMNC) or from plasma from patients. The results obtained in the present study demonstrated that hyperglycemia in diabetes exacerbates in vitro inflammatory responses in PBMNCs stimulated with high levels of SFA (palmitate). These results suggest that hyperglycemia primes PBMNCs for NO, IL-6, and TNF-alpha secretion under in vitro FFA stimulation are associated with the secretion of inflammatory biomarkers in diabetes. A combined therapy targeting signaling pathways activated by hyperglycemia in conjunction with simultaneous control of hyperglycemia and hypertriglyceridemia would be suggested for controlling the progress of diabetic complications.

Malondialdehyde (MDA), an end product of lipid peroxidation and biomarker for oxidative stress, and its soluble receptor (sRAGE) were evaluated in 42 patients with type 1 diabetes mellitus, but without chronic complications, during the early years after diagnosis (0-10 years) and through the further progression of the disease (10-20 and > 20 years after diagnosis). Clinical and biochemical parameters of the cohort of diabetic patients were compared with those determined in 24 healthy individuals. The median levels of MDA in plasma were similar in type 1 diabetes patients and in healthy subjects. In contrast, statistically significant increases were detected in the median values of sRAGE in patients with type 1 diabetes compared with healthy subjects (2423.75 versus 1472.75 pg/ml; p=0.001, Mann-Whitney test). However, no significant between-group differences (p>0.05) were observed in levels of sRAGE when diabetic patients were grouped according to time elapsed after diagnosis. It is concluded that increased plasma levels of sRAGE in type 1 diabetes may provide protection against cell damage and may be sufficient to eliminate excessive circulating MDA during early years after disease onset.

No abstract

Peripheral blood mononuclear cells (PBMNC) from patients with type 2 diabetes (DM2) have generated higher levels of reactive oxygen species (ROS) that were higher than those in cells from healthy individuals. In the presence of a cAMP-elevating agent, ROS production was significantly activated in PBMNC from DM2 patients but it was inhibited in cells from healthy subjects. Higher levels of IL-6 has been detected in the supernatant of PBMNC cultures from DM2 patients in comparison with healthy controls. When cells were cultured in the presence of a cAMP-elevating agent, the level of IL-6 decreased has by 46% in the supernatant of PBMNC from DM2 patients but it remained unaltered in controls. No correlations between ROS and IL-6 levels in PBMNC from DM2 patients or controls have been observed. Secretions of IL-4 or IFN by PBMNC from patients or controls have not been affected by the elevation of cAMP. cAMP elevating agents have activated the production of harmful reactive oxidant down modulated IL-6 secretion by these cells from DM2 patients, suggesting an alteration in the metabolic response possibly due to hyperglicemia. The results suggest that cAMP may play an important role in the pathogenesis of diabetes.