Insulin in the critically ill with focus on cytokines, reactive oxygen species, HLA-DR expression.

Insulin is essential for glucose homeostasis. Insulin/glucose-insulin-potassium (GIK) regimen suppresses the production of tumor necrosis factor-alpha (TNF-alpha), interleukins-6 (IL-6), macrophage migration inhibitory factor (MIF) and other pro-inflammatory cytokines and reactive oxygen species (ROS), enhances the synthesis of endothelial nitric oxide (eNO), and anti-inflammatory cytokines interleukins-4 (IL-4) and interleukin-10 (IL-10). In subjects who are critically ill, monocyte HLA-DR expression was significantly decreased with a concomitant increase in plasma IL-10 and IL-4 concentrations. Large increases in the plasma concentrations of TNF-alpha, IL-6, sustained increase in the expression of leukocyte CD11b/CD18, and ROS generation following surgery and infections were found to be associated with increased mortality. By virtue of its actions on pro- and anti-inflammatory cytokines and ROS, insulin may have the ability to alter HLA-DR expression in the critically ill and thus bring about its beneficial actions in sepsis/septic shock, myocardial recovery following acute myocardial infarction, improve prognosis of those who are critically ill, and suppress inflammation.

Insulin in sepsis and septic shock.

NF-kappaB activation, and elevated concentrations of macrophage migration inhibitory factor (MIF), tumor necrosis factor-alpha (TNF-alpha), interleukin-1(IL-1), IL-6, free radicals, inducible nitric oxide (iNO), and stress hyperglycemia occurs in sepsis and this leads to systemic inflammatory response and myocardial depression seen in sepsis and septic shock. Conversely, insulin suppresses production of MIF, TNF-alpha, IL-1, IL-6, and free radicals, enhances endothelial NO generation, and enhances the production of anti-inflammatory cytokines IL-4, and IL-10, corrects stress hyperglycemia and improves myocardial function. This supports my earlier proposal that insulin (with or without glucose and potassium) therapy to maintain euglycemia suppresses the inflammatory response, improves myocardial function, and thus, is of benefit in acute myocardial infarction, sepsis andseptic shock.