interleukin-8 and Diabetic-Angiopathies

Topics: Cell Survival; Cells, Cultured; Diabetic Angiopathies; Glucose; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Interleukin-1beta; Interleukin-6; Interleukin-8; MAP Kinase Signaling System; Membrane Potential, Mitochondrial; Necroptosis; p38 Mitogen-Activated Protein Kinases; Protective Agents; Reactive Oxygen Species; Receptor-Interacting Protein Serine-Threonine Kinases; Signal Transduction; Sulfides; Tumor Necrosis Factor-alpha

Diabetes mellitus is associated with an increased incidence of cardiovascular events and microvascular complications. Serum amyloid A (SAA), a HDL apolipoprotein is a risk marker for cardiovascular disease. A permanent increase in SAA plasma levels is observed in diabetics. Because SAA acts on leukocytes, we evaluated whether the synthesis of proinflammatory cytokines and migration of neutrophils and monocytes induced by SAA is affected in diabetics. Cells, isolated from human blood, were cultured in the presence of SAA. TNF-alpha, IL-1beta, IL-8 and IL-1ra levels were measured by ELISA in the culture supernatants and in serum of subjects. Neutrophils and monocytes migration were followed in a chemotaxis chamber. We make the novel observation that neutrophils and monocytes of diabetics are more responsive to SAA for the induction of the proinflammatory cytokine IL-1beta and the proangiogenic and chemotactic protein IL-8. Incremental TNF-alpha production was also found to occur when monocytes were stimulated with SAA. Cell migration was also increased. The increased production of cytokines and increased migration of leukocytes from diabetics in response to SAA may contribute to a sustained accumulation and activation of inflammatory cells in the disease. Accordingly, the hyper-responsiveness of leukocytes to SAA may be relevant to the proinflammatory conditions associated to vascular complications in diabetic patients.

Topics: Adult; Aged; Cell Movement; Cells, Cultured; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Humans; Interleukin 1 Receptor Antagonist Protein; Interleukin-1beta; Interleukin-8; Leukocytes; Male; Middle Aged; Models, Biological; Monocytes; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Serum Amyloid A Protein; Tumor Necrosis Factor-alpha

Metformin may benefit the macrovascular complications of diabetes independently of its conventional hypoglycemic effects. Accumulating evidence suggests that inflammatory processes participate in type 2 diabetes and its atherothrombotic manifestations. Therefore, this study examined the potential action of metformin as an inhibitor of pro-inflammatory responses in human vascular smooth muscle cells (SMCs), macrophages (Mphis), and endothelial cells (ECs).. Metformin dose-dependently inhibited IL-1beta-induced release of the pro-inflammatory cytokines IL-6 and IL-8 in ECs, SMCs, and Mphis. Investigation of potential signaling pathways demonstrated that metformin diminished IL-1beta-induced activation and nuclear translocation of nuclear factor-kappa B (NF-kappaB) in SMCs. Furthermore, metformin suppressed IL-1beta-induced activation of the pro-inflammatory phosphokinases Akt, p38, and Erk, but did not affect PI3 kinase (PI3K) activity. To address the significance of the anti-inflammatory effects of a therapeutically relevant plasma concentration of metformin (20 micromol/L), we conducted experiments in ECs treated with high glucose. Pretreatment with metformin also decreased phosphorylation of Akt and protein kinase C (PKC) in ECs under these conditions.. These data suggest that metformin can exert a direct vascular anti-inflammatory effect by inhibiting NF-kappaB through blockade of the PI3K-Akt pathway. The novel anti-inflammatory actions of metformin may explain in part the apparent clinical reduction by metformin of cardiovascular events not fully attributable to its hypoglycemic action.

Topics: Anti-Inflammatory Agents; Atherosclerosis; Cell Survival; Cells, Cultured; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Endothelium, Vascular; Glucose; Humans; Hypoglycemic Agents; Interleukin-1; Interleukin-6; Interleukin-8; Macrophages; Metformin; Muscle, Smooth, Vascular; NF-kappa B; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Saphenous Vein

Levels of platelet-derived microparticles (PMPs), platelet activation markers (P-selectin expressed on, or annexin V binding to, platelets (plt:P-selectin or plt:annexin V, respectively)), chemokines (IL-8, monocyte chemotactic peptide-1 (MCP-1), and regulated on activation normally T-cell expressed and secreted (RANTES)), and soluble P- and E-selectins were compared in peripheral blood from diabetic and control patients in order to develop a better understanding of their potential contribution to diabetic vascular complications. Significant increases were found for PMPs, plt:P-selectin, MCP-1, RANTES and soluble P- and E-selectins in diabetic individuals, whereas IL-8 levels were similar. Furthermore, after ticlopidine treatment, most of these factors receded to baseline levels observed in non-diabetic patients. Our findings indicate that ticlopidine might be able to prevent or reduce vascular complications in diabetic patients.

Topics: Adult; Annexin A5; Blood Platelets; Case-Control Studies; Chemokine CCL2; Chemokine CCL5; Chemokines; Diabetes Mellitus, Type 2; Diabetic Angiopathies; E-Selectin; Female; Humans; Interleukin-8; Male; Middle Aged; P-Selectin; Platelet Activation; Platelet Aggregation Inhibitors; Ticlopidine

We examined the effect of high glucose concentrations on the production of interleukin(IL)-8, which seems to be important for the development of atherosclerosis, in cultured human aortic endothelial cells (AoEC) and smooth muscle cells (AoSMC). After incubating these cells with various concentrations of glucose for 2 days or 7 days, the IL-8 concentration in cell lysates was measured by enzyme-linked immunosorbent assay and the IL-8 mRNA expression was examined by Northern analysis. After 2 days' culture, 42.5 mmol/l glucose enhanced IL-8 mRNA expression in AoEC, but not in AoSMC, compared to 4 mmol/l glucose. After 7 days' culture, the IL-8 concentration in AoEC lysate and the expression of IL-8 mRNA were significantly increased by 20.5 mmol/l glucose, or 42.5 mmol/l glucose compared to 4 mmol/l glucose. On the other hand, the IL-8 concentration in AoSMC lysate was not affected by any glucose concentration and the expression of IL-8 mRNA in AoSMC was diminished by high glucose. These results suggest that the chemotactic gradient by IL-8 is established between arterial intima and media in response to high glucose levels in diabetic patients, and that it may be one of the key factors for SMC migration to the intima leading to diabetic macroangiopathy.

Topics: Aorta; Blotting, Northern; Cells, Cultured; Diabetic Angiopathies; Dose-Response Relationship, Drug; Endothelium, Vascular; Glucose; Humans; Interleukin-8; Models, Biological; Muscle, Smooth, Vascular; Protein Biosynthesis; RNA, Messenger; Transcription, Genetic

Topics: Aorta; Cells, Cultured; Chemotaxis; Diabetic Angiopathies; Endothelium, Vascular; Glucose; Humans; Inflammation; Interleukin-8; Protein Kinase C; Umbilical Veins