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Cecal Ligation (cecal + ligation)
Selected AbstractsImpaired CD4+ T-cell proliferation and effector function correlates with repressive histone methylation events in a mouse model of severe sepsisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2010William F. Carson Abstract Immunosuppression following severe sepsis remains a significant human health concern, as long-term morbidity and mortality rates of patients who have recovered from life-threatening septic shock remain poor. Mouse models of severe sepsis indicate this immunosuppression may be partly due to alterations in myeloid cell function; however, the effect of severe sepsis on subsequent CD4+ T-cell responses remains unclear. In the present study, CD4+ T cells from mice subjected to an experimental model of severe sepsis (cecal ligation and puncture (CLP)) were analyzed in vitro. CD4+CD62L+ T cells from CLP mice exhibited reduced proliferative capacity and altered gene expression. Additionally, CD4+CD62L+ T cells from CLP mice exhibit dysregulated cytokine production after in vitro skewing with exogenous cytokines, indicating a decreased capability of these cells to commit to either the TH1 or TH2 lineage. Repressive histone methylation marks were also evident at promoter regions for the TH1 cytokine IFN-, and the TH2 transcription factor GATA-3 in naïve CD4+ T cells from CLP mice. These results provide evidence that CD4+ T-cell subsets from post-septic mice exhibit defects in activation and effector function, possibly due to chromatin remodeling proximal to genes involved in cytokine production or gene transcription. [source] Complement C5a regulates IL-17 by affecting the crosstalk between DC and ,, T cells in CLP-induced sepsisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2010Ruonan Xu Abstract Complement 5a (C5a) and Interleukin-17 (IL-17) are two important inflammatory mediators in sepsis. Here we studied the mechanisms underlying regulation of IL-17 by anaphylatoxin C5a. We found that C5a blockade increased the survival rate of mice following cecal ligation and puncture (CLP)-induced sepsis and decreased IL-17 expression in vivo. IL-17 was secreted mainly by ,, T cells in this model. Importantly, our data suggest that C5a participates in the regulation of IL-17 secretion by ,, T cells. Dendritic cells (DC) were found to act as a "bridge" between C5a and ,, T cells in a mechanism involving IL-6 and transforming growth factor , (TGF-,). These results imply that C5a affects the crosstalk between DC and ,, T cells during sepsis development, and this may result in a large production of inflammatory mediators such as IL-17. [source] The chemokine receptor CCR6 is an important component of the innate immune responseEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 9 2007Haitao Wen Abstract In our initial studies we found that naïve CCR6-deficient (CCR6,/,) C57BL/6 mice possessed significantly lower number of both F4/80+ macrophages and dendritic cells (DC), but higher number of B cells in the peritoneal cavity, as compared to naïve wild type (WT) controls. Furthermore, peritoneal macrophages isolated from CCR6,/, mice expressed significantly lower levels of inflammatory cytokines and nitric oxide following lipopolysaccharide (LPS)stimulation, as compared to WT macrophages. In a severe experimental peritonitis model induced by cecal ligation and puncture (CLP), CCR6,/, mice were protected when compared with WT controls. At 24,h following the induction of peritonitis, CCR6,/, mice exhibited significantly lower levels of inflammatory cytokines/chemokines in both the peritoneal cavity and blood. Interestingly, DC recruitment into the peritoneal cavity was impaired in CCR6,/, mice during the evolution of CLP-induced peritonitis. Peritoneal macrophages isolated from surviving CCR6,/, mice 3,days after CLP-induced peritonitis exhibited an enhanced LPS response compared with similarly treated WT peritoneal macrophages. These data illustrate that CCR6 deficiency alters the innate response via attenuating the hyperactive local and systemic inflammatory response during CLP-induced peritonitis. [source] Cytochrome c oxidase as the target of the heat shock protective effect in septic liverINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2004Hsiang-Wen Chen Summary Liver function failure is one of the characteristics of critically ill, septic patients and is associated with worse outcome. Our previous studies have demonstrated that heat-shock response protects cells and tissue from subsequent insults and improves survival during sepsis. In this study, we have shown that mitochondrial cytochrome c oxidase (CCO) is one of the major sources of that protective effect. Experimental sepsis was induced by the cecal ligation and puncture (CLP) method. Heat-shock treatment was induced in rats by hyperthermia 24 h before CLP operation. The results showed that ATP content of the liver declined significantly, and the enzymatic activity of mitochondrial CCO was apparently suppressed during the late stages of sepsis. The mitochondrial ultrastructure of septic liver showed the deformity, mild swelling and inner membrane budding. Heat-shock treatment led to heat-shock protein 72 overexpression and prevented the downregulation of Grp75 during sepsis. On the contrary, the expression of the enzyme complex and its activity were preserved, associated with the minimization of ultrastructural deformities. In conclusion, the maintenance of mitochondrial function, especially the CCO, may be an important strategy in therapeutic interventions of a septic liver. [source] Milk Fat Globule EGF Factor 8 Attenuates Sepsis-Induced Apoptosis and Organ Injury in Alcohol-Intoxicated RatsALCOHOLISM, Issue 9 2010Rongqian Wu Background:, Despite advances in our understanding of excessive alcohol-intake-related tissue injury and modernization of the management of septic patients, high morbidity and mortality caused by infectious diseases in alcohol abusers remain a prominent challenge. Our previous studies have shown that milk fat globule epidermal growth factor-factor VIII (MFG-E8), a protein required to opsonize apoptotic cells for phagocytosis, is protective in inflammation. However, it remains unknown whether MFG-E8 ameliorates sepsis-induced apoptosis and organ injury in alcohol-intoxicated rats. The purpose of this study was to determine whether recombinant murine MFG-E8 (rmMFG-E8) attenuates organ injury after acute alcohol exposure and subsequent sepsis. Methods:, Acute alcohol intoxication was induced in male adult rats by a bolus injection of intravenous alcohol at 1.75 g/kg BW, followed by an intravenous infusion of 300 mg/kg BW/h of alcohol for 10 hours. Sepsis was induced at the end of 10-hour alcohol infusion by cecal ligation and puncture (CLP). rmMFG-E8 or vehicle (normal saline) was administered intravenously 3 times (i.e., at the beginning of alcohol injection, the beginning of CLP, and 10 hours post-CLP) at a dose of 20 ,g/kg BW each. Blood and tissue samples were collected 20 hours after CLP in alcoholic animals for various measurements. Results:, Acute alcohol exposure per se did not affect the production of MFG-E8; however, it primed the animal and enhanced sepsis-induced MFG-E8 downregulation in the spleen. Administration of rmMFG-E8 reduces alcohol/sepsis-induced apoptosis in the spleen, lungs, and liver. In addition, administration of rmMFG-E8 after alcohol exposure and subsequent sepsis decreases circulating levels of TNF-, and interleukin-6 and attenuates organ injury. Conclusions:, rmMFG-E8 attenuates sepsis-induced apoptosis and organ injury in alcohol-intoxicated rats. [source] Ascorbate Inhibits Reduced Arteriolar Conducted Vasoconstriction in Septic Mouse Cremaster MuscleMICROCIRCULATION, Issue 7 2007REBECCA L. MCKINNON ABSTRACT Objective: The mechanism of neuronal nitric oxide synthase (nNOS)-dependent reduction in arteriolar conducted vasoconstriction in sepsis, and the possible protection by antioxidants, are unknown. The authors hypothesized that ascorbate inhibits the conduction deficit by reducing nNOS-derived NO production. Methods: Using intravital microscopy and the cecal ligation and perforation (CLP) model of sepsis (24 h), arterioles in the cremaster muscle of male C57BL/6 wild-type mice were locally stimulated with KCl to initiate conducted vasoconstriction. The authors used the ratio of conducted constriction (500 , m upstream) to local constriction as an index of conduction (CR500). Cremaster muscle NOS enzymatic activity and protein expression, and plasma nitrite/nitrate levels were determined in control and septic mice. Intravenous ascorbate bolus (200 mg/kg in 0.1 ml of saline) was given early (0 h) or delayed at 23 h post CLP. Results: Sepsis reduced CR500 from 0.73 ± 0.03 to 0.21 ± 0.03, increased nNOS activity from 87 ± 9 to 220 ± 29 pmol/mg/h and nitrite/nitrate from 16 ± 1 to 39 ± 3 , M, without affecting nNOS protein expression. Ascorbate at 0 and 23 h prevented/reversed the conduction deficit and the increases in nNOS activity and nitrite/nitrate level. NO donor SNAP (S -nitroso- N -acetylpenicillamine) reestablished the conduction deficit in ascorbate-treated septic mice. Superoxide scavenger MnTBAP (Mn(III)tetrakis(4-benzoic acid)porphyrin chloride) did not affect this deficit. Conclusion: These data indicate that early and delayed intravenous boluses of ascorbate prevent/reverse sepsis-induced deficit in arteriolar conducted vasoconstriction in the cremaster muscle by inhibiting nNOS-derived NO production. [source] Platelet Recruitment in the Murine Hepatic Microvasculature During Experimental Sepsis: Role of NeutrophilsMICROCIRCULATION, Issue 2 2006GEORG SINGER ABSTRACT Objectives: Sepsis is a major clinical problem that often results in the dysfunction or failure of multiple organs, including the liver. While inflammatory cell activation has been implicated as an early critical event in sepsis-induced liver dysfunction, there is growing evidence for the involvement of activated platelets in this pathologic process. Methods: Intravital microscopy was used in this study to assess the magnitude and time course of platelet adhesion in the liver microcirculation during experimental sepsis and to determine whether the platelet accumulation is linked to leukocyte infiltration. The adhesion of platelets and leukocytes in terminal hepatic venules (THV) and sinusoids was quantified at 2, 4, and 6 h after abdominal sepsis induced by cecal ligation and puncture (CLP). Results: While the rolling and firm adhesion of platelets and leukocytes in THV were not altered in the first 2 h after CLP, platelet recruitment was observed at 4 h and further elevated at 6 h after CLP. Leukocyte adhesion in THV exhibited a similar time course. A similar accumulation of blood cells in sinusoids was noted after CLP. This was accompanied by an increased number of nonperfused sinusoids. CLP-induced leukocyte and platelet recruitment in THV and sinusoids was attenuated in mice rendered neutropenic with anti-neutrophil serum. Conclusion: These findings indicate that sepsis is associated with a neutrophil-dependent recruitment of platelets in the liver microcirculation that impairs sinusoidal perfusion and may contribute to the liver dysfunction associated with sepsis. [source] | ||||||||||