Acceleration of chemokine production from endothelial cells in response to lipopolysaccharide in hyperglycemic condition

Similar effects of resistin and high glucose on P-selectin and fractalkine expression and monocyte adhesion in human endothelial cells

Resistin and high glucose (HG) are concomitantly present at elevated concentration in diabetic's plasma; both are pro-inflammatory agents acting on vascular cells by mechanisms that are not fully understood. We questioned whether resistin and HG affect the expression of major adhesion molecules, P-selectin and fractalkine in human endothelial cells (HEC). The results showed that in HEC (i) resistin increased P-selectin expression; (ii) HG up-regulated Fk expression; (iii) P-selectin and fractalkine were functional increasing monocyte adhesion to activated cells. Co-stimulation with resistin and HG increased P-selectin and fractalkine mRNA and protein and induced monocyte adhesion, generated an increase in NADPH oxidase activity and of the intracellular reactive oxygen species and activated the NF-kB and AP-1 transcription factors at similar values as those of each activator. In conclusion in HEC, resistin and HG induce the up-regulation of P-selectin and fractalkine and the ensuing increased monocyte adhesion by a mechanism involving oxidative stress and NF-kB and AP-1 activation.

Hyperglycemia and lipopolysaccharide decrease depression effect of interleukin 8 production by hypothermia: an experimental study with endothelial cells

OBJECTIVE

This study assessed whether hyperglycemia and lipopolysaccharide (LPS) decrease the depression effect of interleukin (IL) 8 production by hypothermia in endothelial cells.

DESIGN AND SETTING

Laboratory study in a university laboratory.

SUBJECTS

Human umbilical vein endothelial cells (HUVECs).

INTERVENTIONS

HUVECs were cultivated in various concentrations of glucose (5.5 or 16.5mM = 100 or 300mg/dl) with or without LPS stimulation for 5, 12, or 24h at either 30 degrees or 37 degrees C.

RESULTS

After culturing, IL-8 mRNA expressions and IL-8 levels were measured. At 37 degrees C, hyperglycemia significantly increased basal IL-8 mRNA at 12h and basal IL-8 at 24h. At 37 degrees C hyperglycemia significantly increased LPS-stimulated IL-8 mRNA at 12h and LPS-stimulated IL-8 at 12 and 24h. At 30 degrees C basal IL-8mRNA, basal IL-8, and LPS-stimulated IL-8 were significantly decreased by hypothermia, but these hypothermic effects were not observed in LPS-stimulated IL-8 mRNA. Furthermore even at 30 degrees C hyperglycemia significantly increased LPS-stimulated IL-8 mRNA at all time points and LPS stimulated IL-8 at 24h.

CONCLUSIONS

Hypothermia (30 degrees C) decreases the production of IL-8 in HUVECs but does not decrease the expression of IL-8 mRNA. When hypothermia is followed by hyperglycemia and LPS stimulation, such a combination may expose the patients to a high risk of secondary tissue damage during therapeutic hypothermia.

Glucose metabolism in lymphoid and inflammatory cells and tissues

PURPOSE OF REVIEW

To examine the role of glucose as a fuel for immune cells and the influence of glucose supply on immune-cell functional responses.

RECENT FINDINGS

Immune cells express the insulin receptor and a range of glucose-transporter isoforms. Glucose transporters are responsive to both immune stimulation and insulin. The pattern of glucose-transporter upregulation differs among different types of immune cell. In-vitro studies reveal that both hypo- and hyperglycaemia impair immune-cell functions and promote inflammatory responses. Clamp studies have revealed proinflammatory effects of hyperglycaemia and antiinflammatory and immune-promoting effects of insulin.

SUMMARY

Glucose is readily utilized by cells of the immune system and is used to generate energy and biosynthetic precursors. Activation of immune cells is associated with increased glucose utilization and this is facilitated, in part, by increased expression of glucose transporters. Immune cells express the insulin receptor and respond to insulin. Both hypo- and hyperglycaemia impair immune-cell functions and promote inflammatory responses. Insulin therapy in hyperglycaemic subjects may be of benefit through effects of both insulin itself and lowered glucose concentration. Excessive lowering of blood glucose concentration may also be harmful to the immune response.