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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Aberrant activation of neutrophils during sepsis results in the widespread release of proinflammatory mediators, leading to multiorgan system failure and death. However, aberrant activation of neutrophils during sepsis results in the widespread release of harmful inflammatory mediators causing host tissue injuries that can lead to multiorgan system failure and death. ⋯ Second, β1 integrin (CD29) was highly upregulated on the neutrophils isolated from both septic patients and animals. Finally, conditional genetic ablation of β1 integrin from granulocytes also improved survival and bacterial clearance in septic animals Thus, our results indicate that expression of β1 integrin is important for modulating neutrophil trafficking during sepsis and that therapeutics designed against β1 integrins may be beneficial.
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Large surface area burn injuries lead to activation of the innate immune system, which can be blocked by parasympathetic inputs mediated by the vagus nerve. We hypothesized that vagal nerve stimulation (VNS) would alter the inflammatory response of peritoneal macrophages after severe burn injury. Male BALB/c mice underwent right cervical VNS before 30% total body surface area steam burn and were compared with animals subjected to burn alone. ⋯ We identified a protective role for VNS in blocking peritoneal macrophage activation. Analysis of the phosphorylation state of nuclear factor κB pathway mediator, p65 Rel A, revealed a VNS-mediated reduction in p65 phosphorylation levels after exposure to LPS compared with burn alone. In combination, these studies suggest VNS mediates the inflammatory response in peritoneal macrophages by affecting the set point of LPS responsiveness.
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The hemoglobin vesicle (Hb-vesicle) is a cellular-type artificial oxygen carrier showing a resuscitative effect comparable to that of blood transfusion in several animal models. However, the efficacy of Hb-vesicles for resuscitation when the hemorrhage cannot be controlled remains unclear. Therefore, we used Hb-vesicles in a rat hemorrhagic shock model caused by continuous bleeding. ⋯ Meanwhile, the hematocrit levels of the HbV, Alb, and HES groups showed sharp decreases (HbV: 6.8% ± 1.7%, Alb: 6.8% ± 0.8%, HES: 5.5% ± 0.7% at 100% total circulated blood volume; final hematocrit of the HbV group: 1.5% ± 0.5%). These results suggest that shocked animals can survive longer when the Hb-vesicle supply is maintained and that HbV showed a similar effect to wRBC in maintaining the circulating volume and oxygen metabolism. Continuous infusion of Hb-vesicles may extend the survival of trauma victims with uncontrolled hemorrhage until they have reached a trauma center.
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Since the definition of systemic inflammatory response syndrome/sepsis was originally proposed, a large amount of new information has been generated showing a much more complex scenario of inflammatory and counterinflammatory responses during sepsis. Moreover, some fundamental mechanisms of sensing and destroying invading microorganisms have been uncovered, which include the discovery of TLR4 as the lipopolysaccharide (LPS) gene, implications of innate immune cells as drivers of the adaptive response to infection, and the modulation of multiple accessory molecules that stimulate or inhibit monocyte/macrophage and lymphocyte interactions. ⋯ In this review, we discuss aspects of bacterial recognition and induced cellular activation during sepsis. Because of the relevance of endotoxin (LPS) research in the field, we focus on LPS and host interactions as a clue to understand microorganisms sensing and cell signaling, then we discuss how this response is modulated in septic patients.
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Kidney ischemia-reperfusion injury (IRI) activates cellular and soluble mediators that drive lung inflammatory cascades, tumor necrosis factor receptor 1 (TNFR1)-mediated programmed cell death, and microvascular barrier dysfunction, leading to acute lung injury. We hypothesized that lung microvascular endothelial cells (ECs), with their integral role in maintaining the lung-semipermeable barrier, were key cellular targets of TNFR1-mediated apoptosis during ischemic AKI. Male C57/BL6 mice and Sprague-Dawley rats underwent 60 min of bilateral renal pedicle occlusion (IRI) or sham laparotomy (sham) and were killed at 4 or 24 h. ⋯ Compared with vehicle, treatment of rat lung microvascular ECs with etanercept inhibited proinflammatory gene activation (E-selectin, intercellular adhesion molecule 1, interleukin 6, RhoB) and apoptosis during ischemic AKI. Ischemic AKI drives distinct proinflammatory and proapoptotic changes in the pulmonary EC transcriptome with TNFR1-dependent caspase activation and programmed cell death. Further investigation of potential EC mechanisms of kidney-lung crosstalk during AKI may identify potential therapeutic targets for this deadly disease.