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 24 h. 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.