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 peroxisome proliferator-activated receptor α (PPAR-α) is a member of the nuclear receptor family with many important physiologic roles related to metabolism and inflammation. Previous research in pediatric patients with septic shock revealed that genes corresponding to the PPAR-α signaling pathway are significantly downregulated in a subgroup of children with more severe disease. In this study, PPAR-α expression analysis using whole-blood derived RNA revealed that PPAR-α expression was decreased in patients with septic shock and that the magnitude of that decrement correlated with the severity of disease. ⋯ Plasma cytokine analysis demonstrated decreased levels of interleukin 1β (IL-1β), IL-6, IL-17, keratinocyte-derived cytokine, macrophage chemoattractant protein 1, macrophage inflammatory protein 2, and tumor necrosis factor α at 24 h in PPAR-α knockout animals. Cell surface markers of activation on splenic dendritic cells, macrophages, and CD8 T cells were reduced in PPAR-α null animals, and the bacterial load in lung and splenic tissues was increased. These data indicate that reduced or absent PPAR-α expression confers a survival disadvantage in sepsis and that PPAR-α plays a role in maintaining appropriate immune functions during the sepsis response.
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Excessive endoplasmic reticulum stress (ERS) disrupts protein translation, protein folding, and calcium homeostasis and may contribute to ischemia-reperfusion injury. Saponins extracted from the stems and leaves of Panax quinquefolium (PQS) protect rat myocardium against ischemia-reperfusion injury, but it is not known if suppression of ERS contributes to cardioprotection. Neonatal rat cardiomyocytes were subjected to hypoxia-reoxygenation (H-R) in the presence of PQS or vehicle. ⋯ We confirmed that PQS protects cardiomyocytes from H-R-induced injury and apoptotic cell death. Furthermore, PQS suppressed H-R-induced excessive ERS, as evidenced by reduced caspase 12 activation and decreased glucose-regulated protein 78, calreticulin, and CCAAT/enhancer-binding protein homologous protein overexpression. These results indicated that PQS could alleviate H-R injury of cardiomyocytes, which would be probably related to inhibiting excessive ERS induced by H-R.
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Cardiac cycle is regulated by a complex interplay between autonomic nervous system and cardiac pacemaker cells. Decreased heart rate variability (HRV) and increased cardiac rhythm regularity are associated with poor prognosis in patients with systemic inflammation (e.g., sepsis). However, the underlying mechanism of decreased HRV in systemic inflammation is not understood. ⋯ The chronotropic responsiveness to adrenergic stimulation was identical in controls and endotoxin-treated rats. These data propose that systemic inflammation is linked to reduced cardiac responsiveness to cholinergic stimulation. This may lead to partial uncoupling of cardiac pacemaker cells from autonomic neural control and can explain decreased HRV during systemic inflammation.
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The objective of the study was to investigate the mechanisms of insufficient interferon-γ (IFN-γ) response to interleukin 18 (IL-18) and the treatment for the insufficient response in septic mice. Interleukin 18 stimulation does not restore IFN-γ production by blood mononuclear cells in septic patients but does restore its production in postoperative patients. Although sepsis impairs the IFN-γ response to IL-18, little is known about why the IL-18/IFN-γ-mediated immune response is ineffective in patients with sepsis. ⋯ Neutralization of IL-10 restored the IL-18R expression on liver NK cells and restored the IFN-γ response in the septic mice, improving their survival. Sepsis might impair IL-18R expression on liver and spleen NK cells and impair the IL-18-mediated IFN-γ response. Neutralization of IL-10 may restore this response in septic hosts, thereby improving survival.
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Hypothermia is considered an independent predictor of death after trauma. The aim of this study was to assess these premises based on data from the TraumaRegistry DGU® (TR-DGU) using its outcome predication tool, the Revised Injury Severity Classification (RISC) score, in comparison with three previously published regression models by Shafi, Martin, and Wang. We hypothesized that body temperature on admission would improve accuracy of the RISC score. ⋯ Comparison of the above models revealed hypothermia as an independent risk factor (Martin: OR, 1.43 [95% CI, 2.21-1.42*]; and Wang: OR, 1.77 [95% CI, 2.21-1.42*]) only, although it would drop out from the model (RISC: OR, 1.12 [95% CI, 1.41-0.89; P = 0.33] and Shafi: OR, 1,.21 [95% CI, 1.60-0.92; P = 0.17]) as long as parameters to indicate hemorrhage and/or coagulopathy were included in sufficient number, a finding confirmed by a subsequent sensitivity analysis. We conclude that hypothermia is a result of injury severity and therefore unlikely to be an independent predictor of mortality. Our data suggest that hypothermia belongs closely to the hemorrhage/coagulopathy group of predictors.