BACKGROUND: Sepsis continues to be a leading cause of morbidity and mortality in newborns. OBJECTIVE: As both nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) appear to be critical mediators in inflammatory response, we studied the effects of lipopolysaccharide (LPS) on expression and function of NF-κB and p38 MAPK in whole neonatal cord and adult blood. METHODS: Th1/Th2 cytokine concentrations and phosphorylation of NF-κB and p38 MAPK were determined by flow-cytometric analysis. RESULTS: Tumor necrosis factor-alpha (TNF-α), IL-6, and IL-10 concentrations were significantly elevated in supernatants of neonatal and adult blood after LPS stimulation for 4 h. IFN-γ, IL-4, and IL-2 showed no significant alterations. Furthermore, TNF-α concentrations were significantly higher in adult compared to neonatal blood after LPS stimulation. Stimulation with LPS resulted in significantly decreased activation of p38 MAPK in neonatal blood, whereas NF-κB showed no difference. Following inhibition of p38 MAPK with the specific inhibitor SB-202190, levels of TNF-α and IL-6 significantly decreased in neonatal and adult blood, whereas pharmacological inhibition of NF-κB with SC-514 showed no significant effect on cytokine expression. CONCLUSIONS: We conclude that p38 MAPK phosphorylation is crucially involved in LPS activation and could explain the differences in early cytokine response between neonatal and adult blood.
BACKGROUND: Sepsis continues to be a leading cause of morbidity and mortality in newborns. OBJECTIVE: As both nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) appear to be critical mediators in inflammatory response, we studied the effects of lipopolysaccharide (LPS) on expression and function of NF-κB and p38 MAPK in whole neonatal cord and adult blood. METHODS:Th1/Th2 cytokine concentrations and phosphorylation of NF-κB and p38 MAPK were determined by flow-cytometric analysis. RESULTS:Tumor necrosis factor-alpha (TNF-α), IL-6, and IL-10 concentrations were significantly elevated in supernatants of neonatal and adult blood after LPS stimulation for 4 h. IFN-γ, IL-4, and IL-2 showed no significant alterations. Furthermore, TNF-α concentrations were significantly higher in adult compared to neonatal blood after LPS stimulation. Stimulation with LPS resulted in significantly decreased activation of p38 MAPK in neonatal blood, whereas NF-κB showed no difference. Following inhibition of p38 MAPK with the specific inhibitor SB-202190, levels of TNF-α and IL-6 significantly decreased in neonatal and adult blood, whereas pharmacological inhibition of NF-κB with SC-514 showed no significant effect on cytokine expression. CONCLUSIONS: We conclude that p38 MAPK phosphorylation is crucially involved in LPS activation and could explain the differences in early cytokine response between neonatal and adult blood.