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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This study was conducted to reveal if the mitochondrial unfolded protein response (mtUPR), a conserved mitochondrial-nuclear communication mechanism, plays a critical role in the protein quality control system to cope with damaged protein during sepsis. Sepsis was induced by cecal ligation and puncture (CLP) in Sprague-Dawley rats. The efficiency of mtUPR was evaluated by measuring the transcriptional factors (CCAAT/enhancer-binder protein homologous protein [CHOP] and CCAAT/enhancer-binder protein-β) and chaperones (heat shock protein 60 [Hsp60] and Hsp10) expression in response to hepatic mitochondrial oxidized proteins (carbonylated proteins, car-proteins) and multi-ubiquitinated proteins (ub-proteins). ⋯ Interestingly, we evaluated the ratio of mitochondrial Hsp60/Hsp10 to the ub-proteins and found that both ratios were statistically lowered at the time points of 9 and 18 h in comparison with 3 and 6 h after CLP. These ratios were also significantly negatively correlated with glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase levels, suggesting that the ratios could act as an index of mtUPR failure and be a useful tool in estimating the ability of mitochondrial-nuclear communication in sepsis. In conclusion, the results indicated that mtUPR failure occurred during sepsis, and that the index of mtUPR may be a valuable measurement in assessing the severity of organ dysfunction in the clinical setting.
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The mechanism of immunosuppression induced by severe sepsis is not fully understood. The production of prostaglandin E2 (PGE2) during sepsis is well known, but its role in long-term consequences of sepsis has not been explored. The current study evaluates the role of PGE2 in the development of immunosuppression secondary to sepsis and its potential as therapeutic target. ⋯ Furthermore, sepsis also altered key enzymes in PGE2 synthesis and degradation. Our results indicate the involvement of PGE2 in severe sepsis-induced immunosuppression. Inhibition of PGE2 production represents an attractive target to improve innate immune response against secondary infection in the immunocompromised host.
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Blood transfusion is a well-established risk factor for adverse outcomes during sepsis. The specific mechanisms responsible for this effect remain elusive, and few studies have investigated this phenomenon in a model that reflects not only the clinical circumstances in which blood is transfused, but also how packed red blood cells (PRBCs) are created and stored. Using a cecal ligation and puncture model of polymicrobial sepsis as well as creating murine allogeneic and stored PRBCs in a manner that replicates the clinical process, we have demonstrated that transfusion of PRBCs induces numerous effects on leukocyte subpopulations. ⋯ Myeloid cells behaved similarly, although they were able to produce more reactive oxygen species. Overall, transfusion in the septic mouse may contribute to the persistent immune dysfunction known to be associated with this process, rather than simply promote proinflammatory or anti-inflammatory effects on the host. Thus, it is possible that blood transfusion contributes to the multiple known effects of sepsis on leukocyte populations that have been shown to result in increased morbidity and mortality.
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Combination therapy with molecular hydrogen and hyperoxia in a murine model of polymicrobial sepsis.
Sepsis is the most common cause of death in intensive care units. Some studies have found that hyperoxia may be beneficial to sepsis. However, the clinical use of hyperoxia is hindered by concerns that it could exacerbate organ injury by increasing free radical formation. ⋯ However, combination therapy with H2 and hyperoxia had a more beneficial effect against lung, liver, and kidney damage of moderate or severe CLP mice. Furthermore, we found that the beneficial effect of this combination therapy was associated with the decreased levels of oxidative product (8-iso-prostaglandin F2α), increased activities of antioxidant enzymes (superoxide dismutase and catalase) and anti-inflammatory cytokine (interleukin 10), and reduced levels of proinflammatory cytokines (high-mobility group box 1 and tumor necrosis factor α) in serum and tissues. Therefore, combination therapy with H2 and hyperoxia provides enhanced therapeutic efficacy via both antioxidant and anti-inflammatory mechanisms and might be potentially a clinically feasible approach for sepsis.