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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Although studies in rat cultured pulmonary artery endothelial cells, perfused lungs, and intact mice support the concept that oxidative mitochondrial (mt) DNA damage triggers acute lung injury (ALI), it has not yet been determined whether enhanced mtDNA repair forestalls development of ALI and its progression to multiple organ system failure (MOSF). Accordingly, here we examined the effect of a fusion protein construct targeting the DNA glycosylase, Ogg1, to mitochondria in a rat model intra-tracheal Pseudomonas aeruginosa (strain 103; PA103)-induced ALI and MOSF. Relative to controls, animals given PA103 displayed increases in lung vascular filtration coefficient accompanied by transient lung tissue oxidative mtDNA damage and variable changes in mtDNA copy number without evidence of nuclear DNA damage. ⋯ While administration of mt-targeted Ogg1 to control animals was innocuous, the active fusion protein, but not a DNA repair-deficient mutant, prevented bacteria-induced increases in lung tissue oxidative mtDNA damage, failed to alter mtDNA copy number, and attenuated lung endothelial barrier degradation. These changes were associated with suppression of liver, kidney, and cardiovascular dysfunction and with decreased 24 h mortality. Collectively, the present findings indicate that oxidative mtDNA damage to lung tissue initiates PA103-induced ALI and MOSF in rats.
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All-trans-retinoic acid (ATRA) is a derivative of vitamin A with antiproliferative properties. Endotoxin shock and subsequent immunosuppression (IS) by lipopolysaccharide (LPS) stimulates myelopoiesis with expansion of myeloid-derived suppressor cells (MDSC). Since we have previously shown that ATRA reverses the IS state by decreasing functional MDSC, our aim was to investigate if ATRA was able to modulate MDSC generation by regulating myelopoiesis in murine hematopoietic organs. ⋯ Our results indicate, for the first time, a new use of ATRA to abolish LPS-induced myelopoiesis, affecting the proliferation of precursor cells, and in consequence, decreasing MDSC generation, having a direct impact on the improvement of immune competence. Administration of ATRA could overcome the immunosuppressive state generated by sepsis that often leads to opportunistic life-threatening infections. Therefore, ATRA could be considered a complementary treatment to enhance immune responses.
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Leptin is thought to play an important role in the regulation of the immune system. In patients, leptin is inversely proportional to interleukin-6 (IL-6) levels. Thus, the objective of our study was to evaluate a dose-dependent therapeutic impact of leptin with possible IL-6-dependency on immune actions and outcome in a trauma/sepsis model. ⋯ Due to the fact that leptin administration to traumatized and septic mice seems to have a positive effect on their outcome via IL-6 and does not negatively impact their medical condition if applied preventively, leptin might be a therapeutic agent for the prevention, or treatment of sepsis-related detrimental outcome after initial trauma.
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The anti-inflammatory effect of miR-155 was closely linked to transforming growth factor-β-activated kinase-1-binding protein 2 (TAB2) and autophagy. This study investigated the role of miR-155 in attenuation of septic lung injury through TAB2 and autophagy in mouse model and in vitro. ⋯ The current study observed a higher level of miR-155 in the BALF from sepsis patients with acute respiratory distress syndrome and demonstrated that miR-155 alleviated inflammation in septic lung injury in mouse and cell models by inducing autophagy via inhibition of TAB2.
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In patients with sepsis-induced multi-organ dysfunction syndrome, diverging patterns of oedema formation and loss of function in organs such as lung and kidney suggest that endothelial permeability-regulating molecular responses are differentially regulated. This potential differential regulation has been insufficiently studied at the level of components of adherens and tight junctions. We hypothesized that such a regulation by endothelial cells in sepsis takes place in an organ-specific manner. ⋯ In contrast, in kidney we found expression patterns of these molecules compatible with decreased permeability. Finally, we partially corroborated our findings in mouse kidney in human kidneys from septic patients. These findings may help to understand the clinical difference in the extent of oedema formation in kidney and lung in sepsis-associated organ failure.