Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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The investigation of the trauma-induced innate immune responses is hampered by the wide variability in patients, type of trauma, and environmental factors. To circumvent this heterogeneity, we examined whether the systemic innate immune response toward human experimental endotoxemia is similar to the response during systemic inflammatory response syndrome after trauma. We tested the hypothesis that the innate immune response to pathogen-associated molecular pattern (e.g., lipopolysaccharides [LPSs]) and danger-associated molecular pattern (as induced by injury) leads to a comparable in vivo activation of human neutrophils. ⋯ A significant difference between both conditions was seen in CD66b expression and for endotoxin resulted in an increased CD66b expression, whereas injury did not. Neutrophil activation was present 3 h after onset of inflammation, both during experimental endotoxemia as well as in trauma patients. Endotoxin and trauma appear to induce a similar neutrophil activation phenotype.
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Polymorphonuclear granulocytes (PMNs) have been attributed a primarily deleterious role in the pathogenesis of acute lung injury (ALI). However, evidence exists that PMNs might also act beneficially in certain types of ALI. In this regard, we investigated the role of activated neutrophils in the pathophysiology of lung contusion-induced ALI. ⋯ In the presence of PMNs, BAL protein was further increased at 30 h when compared with the 3-h time point, which was not the case in the absence of PMNs. Taken together, in response to lung trauma, activated neutrophils control inflammation including mediator release from distant immune cells but simultaneously mediate pulmonary tissue damage. Thus, keeping in mind potential inflammatory adverse effects, modulation of neutrophil activation or trafficking might be a reasonable therapeutic approach in chest trauma-induced lung injury.
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The treatment of acute lung injury and septic complications after blunt chest trauma remains a challenge. Inhaled hydrogen sulfide (H₂S) may cause a hibernation-like metabolic state, which refers to an attenuated systemic inflammatory response. Therefore, we tested the hypothesis that inhaled H₂S-induced suspended animation may attenuate the inflammation after pulmonary contusion. ⋯ Furthermore, H₂S inhalation partially attenuated the mediator release in BAL and culture supernatants of Kupffer cells as well as splenic cells; it altered plasma cytokine concentrations but did not affect the trauma-induced changes in mononuclear cell culture supernatants. These findings indicate that inhaled H₂S induced a reduced metabolic expenditure and partially attenuated inflammation after trauma. Nevertheless, in contrast to hypoxic- or pathogen-induced lung injury, H₂S treatment appears to have no protective effect after blunt chest trauma.
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Septic shock is the most common cause of death in intensive care units. During the last two decades, new strategies have focused on the diagnosis and on the immunological changes in critically ill patients. There have been conflicting reports whether monocyte human leukocyte antigen (HLA) DR expression poses a useful parameter to characterize clinical outcome of these patients. ⋯ As expected, HLA-DR expression was significantly higher in the group of survivors (n = 279) than in the group of nonsurvivors (n = 134; mABs/cell: 23,038 [SD, 11,150] vs. 18,070 [SD, 8,906]; P < 0.001). When minimal HLA-DR values per patient were compared, no cutoff values could be identified between the groups of survivors and nonsurvivors (mABs/cell: 19,611 [SD, 11,129] vs. 14,944 [SD, 8,013]; P < 0.001). In conclusion, in this sizable cohort we could again show that HLA-DR expression is decreased in critically ill patients but it is not suitable as a prognostic or predictive parameter for clinical outcome.