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
-
Exocytosis of granules containing the cytolytic effector (CE) molecules granzyme A (GzmA), granzyme B (GzmB), and perforin is one major pathway of lymphocyte-mediated cytotoxicity. Studies in murine models and the finding of elevated granzyme levels in the plasma of septic patients have implicated cytotoxic lymphocytes in the pathogenesis of sepsis. We sought to evaluate the role of cytotoxic cells and CE in sepsis and determine if intracellular levels of CE in cytotoxic cells correlate with disease severity. ⋯ The GMFI of each GzmA and GzmB in CTLs were associated with the Acute Physiology and Chronic Health Evaluation II score (P = 0.01). A significant increase in the number of granulocytes in the peripheral blood mononuclear cells of SS patients consisted primarily of low-density neutrophils, which expressed increased levels of GzmA (P < 0.01). The results suggest that CTLs are activated in SS and express significantly higher intracellular levels of GzmB and that GzmA and B levels correlate with disease severity.
-
Recently, we reported that Brown Norway (BN) rats were more resistant to lipopolysaccharide (LPS)-induced myocardial dysfunction than Dahl S (SS) rats. This differential sensitivity was exemplified by reduced production of proinflammatory cytokines and diminished nuclear factor-κB pathway activation. To further clarify the mechanisms of different susceptibility of these two strains to endotoxin, this study was designed to examine the alterations of cardiac and mitochondrial bioenergetics, proinflammatory cytokines, and signaling pathways after hearts were isolated and exposed to LPS ex vivo. ⋯ In addition, LPS significantly decreased complex I activity in SS hearts but not in BN hearts. Furthermore, LPS induced higher levels of tumor necrosis factor-α and increased phosphorylation of IκκB and p65 more in SS hearts than in BN hearts. Our results clearly demonstrate that less mitochondrial dysfunction combined with a reduced production of tumor necrosis factor-α and diminished activation of nuclear factor-κB are involved in the mechanisms by which isolated BN hearts were more resistant to LPS-induced myocardial dysfunction.
-
Serum micro-RNAs (miRNAs) can be used for the diagnosis and prognosis of various diseases. Using genome-wide scans, we sought to identify serum miRNAs that could be used as prognostic predictors for sepsis patients. We used microarray screens to identify differentially expressed serum miRNAs by comparing samples from 12 surviving and 12 nonsurviving sepsis patients. ⋯ When the cutoff point was set at 0.288, these three combined variables provided 78.13% sensitivity and 91.84% specificity. Our results showed that serum miR-574-5p was correlated with the death of sepsis patients. The combined predictive capability of sepsis stage, Sepsis-Related Organ Failure Assessment scores, and serum miR-574-5p for the death of sepsis patients was better than any single indicator.
-
β-Catenin, a key regulator of barrier integrity, is an important component of the adherens junctional complex. Although the roles of β-catenin in maintaining the adherens junctions and Wnt signaling are known, the dynamics of β-catenin following insult and its potential role in vascular recovery/repair remain unclear. Our objective was to define β-catenin's dynamics following disruption of the adherens junctional complex and subsequent recovery. ⋯ Inhibition of GSK-3β and the transfection of β-catenin vector increased Tcf-mediated transcription significantly (P < 0.05). The dissociated adherens junctional protein β-catenin translocates into the cytoplasm, resulting in microvascular hyperpermeability followed by a time-dependent recovery and relocation to the cell membrane. Our data suggest a recycling pathway for β-catenin to the cell junction.
-
Excessive neutrophil infiltration is a major component in septic lung injury, although the signaling mechanisms behind pulmonary recruitment of neutrophils in polymicrobial sepsis remain elusive. Herein, we hypothesized that Rho-kinase activity may play a significant role in pulmonary neutrophil recruitment and tissue damage in abdominal sepsis. Male C57BL/6 mice were treated with the Rho-kinase inhibitor Y-27632 (0.5 or 5 mg/kg) before cecal ligation and puncture (CLP). ⋯ Moreover, Rho-kinase inhibition significantly reduced sepsis-provoked gene expression of CXC chemokines in alveolar macrophages. In contrast, Rho-kinase inhibition had no effect on platelet shedding of CD40L or plasma levels of MMP-9 in septic mice. In conclusion, these data demonstrate that the Rho-kinase signaling pathway plays a key role in regulating pulmonary infiltration of neutrophils and tissue injury via regulation of CXC chemokine production in the lung and Mac-1 expression on neutrophils in abdominal sepsis.