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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Methicillin-resistant Staphylococcus aureus (MRSA) pneumonia-induced sepsis is a common cause of morbidity in the intensive care unit. Although pneumonia is initiated in the lungs, extrapulmonary manifestations occur commonly. In light of the key role the intestine plays in the pathophysiology of sepsis, we sought to determine whether MRSA pneumonia induces intestinal injury. ⋯ To determine if these findings were organism-specific, similar experiments were performed in mice subjected to Pseudomonas aeruginosa pneumonia. Pseudomonas aeruginosa induced gut apoptosis, but unlike MRSA, this was associated with increased Bcl-2 and TNF-R1 and decreased Fas. Methicillin-resistant S. aureus pneumonia thus induces organism-specific changes in intestinal apoptosis via changes in both the mitochondrial and receptor-mediated pathways, although the former may be more functionally significant.
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The effects of acute and prior exposure to lipopolysaccharide (LPS) and staphylococcal enterotoxin B (SEB) on superoxide release by monocytes were examined in control subjects and in patients with sepsis and septic shock during the acute stage and recovery. High doses of LPS, PMA (phorbol 12-myristate 13-acetate), and SEB stimulated monocyte superoxide release in control subjects (P < 0.05). Pretreatment of normal monocytes with these doses of LPS, PMA, and SEB induced significant hyporesponsiveness to subsequent challenge (P < 0.01), and evidence of cross-tolerance was observed. ⋯ In addition, the superoxide release in response to the same stimuli was significantly increased when compared with release during the acute stage (P < 0.05). These data demonstrate that both LPS and SEB induce hyporesponsiveness to LPS- or SEB-stimulated superoxide release. A similar pattern of hyporesponsiveness was observed during sepsis that may represent a mechanism for modulating the inflammatory response during severe infections.
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Interactions of toll-like receptors (TLRs) with nonmicrobial factors play a major role in the pathogenesis of early trauma-hemorrhagic shock (T/HS)-induced organ injury and inflammation. Thus, we tested the hypothesis that TLR4 mutant (TLR4 mut) mice would be more resistant to T/HS-induced gut injury and polymorphonuclear neutrophil (PMN) priming than their wild-type littermates and found that both were significantly reduced in the TLR4 mut mice. In addition, the in vivo and ex vivo PMN priming effect of T/HS intestinal lymph observed in the wild-type mice was abrogated in TLR4 mut mice as well the TRIF mut-deficient mice and partially attenuated in Myd88 mice, suggesting that TRIF activation played a more predominant role than MyD88 in T/HS lymph-induced PMN priming. ⋯ None of these "danger" proteins appeared to be involved, because their levels were similar between the sham and shock lymph samples. In conclusion, TLR4 activation is important in T/HS-induced gut injury and in T/HS lymph-induced PMN priming and lung injury. However, the T/HS-associated effects of TLR4 on gut barrier dysfunction can be uncoupled from the T/HS lymph-associated effects of TLR4 on PMN priming.
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Multiple organ failure is a common outcome of hemorrhagic shock followed by resuscitation, and the kidney is one of the prime target organs involved. The main objective of the study was to evaluate whether crocetin, a natural product from Gardenia jasminoides Ellis, has beneficial effects on renal dysfunction caused by hemorrhagic shock and resuscitation in rats. Anesthetized rats were bled to reduce mean arterial blood pressure to 35 (SD, 5) mmHg for 60 min and then were resuscitated with their withdrawn shed blood and normal saline. ⋯ Hemorrhagic shock resulted in a significant elevation in malondialdehyde production and was accompanied by a reduction in total superoxide dismutase activity, activation of nuclear factor κB, and overexpression of inducible nitric oxide synthase. These changes were significantly attenuated by crocetin at 2 h after resuscitation. These results suggested that crocetin blocks inflammatory cascades by inhibiting production of reactive oxygen species and restoring superoxide dismutase activity to ameliorate renal dysfunction caused by hemorrhage shock and resuscitation.
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Tropisetron is widely used for antiemesis. Recent evidence shows that tropisetron possesses anti-inflammatory properties. Protein kinase B (Akt) is known to play an important role in negating proinflammatory response in injury. ⋯ Although trauma-hemorrhage decreased cardiac Akt phosphorylation (p-Akt), tropisetron treatment prevented the same decrease in cardiac p-Akt following trauma-hemorrhage. Coadministration of wortmannin prevented the beneficial effects of tropisetron on the attenuation of proinflammatory responses and cardiac injury after trauma-hemorrhage. Tropisetron attenuates cardiac injury following trauma-hemorrhage, which is, at least in part, through Akt-dependent anti-inflammatory pathway.