Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0031154 (peritonitis)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regulation of the phagocyte apoptotic response appears to play a significant role in the pathophysiology of sepsis. In this regard, prior studies have shown that the onset of phagocyte apoptosis, as well as those agents that regulate it at the nidus of infection, differ significantly from those seen in circulation. The aim of this study therefore was to determine if the increase in inducible phagocyte apoptosis and caspase activities seen in the peritoneum during sepsis is due to endotoxin or Fas ligand. To study this, male C3H/HeN (endotoxin-sensitive), C3H/HeJ (endotoxin-tolerant), and C3H/HeJ-FasL(gld) (endotoxin-tolerant/FasL-deficient) mice were subjected to cecal ligation and puncture or sham operation. Twenty-four hours later, phagocytes were collected and cultured with lipopolysaccharide (LPS), then harvested for apoptosis (propidium iodide cell cycle or cell death ELISA analysis), cytokine release (ELISA), and caspase activity (fluorogenic assay) determination. The data indicate that there was a marked increase in apoptosis in LPS-stimulated phagocytes which was associated with a significant increase in caspase 3, 8, and 9 activities but a decrease in caspase 1 activity from C3H/HeN and C3H/HeJ-FasL(gld) septic mice and an increase in caspase 3 and 8 activities in phagocytes from C3H/HeJ septic mice. Furthermore, cells from septic mice, including all three strains, lost their ability to produce IL-1beta and IL-6 in response to LPS stimulation. The inability to completely suppress these changes suggests that neither endotoxin (via signaling through TLR-4 pathway) nor Fas ligand regulates the peritoneal phagocyte apoptotic responses seen during the late phase of polymicrobial sepsis/peritonitis.
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PMID:Neither Fas ligand nor endotoxin is responsible for inducible peritoneal phagocyte apoptosis during sepsis/peritonitis. 1083 64

Toll-like receptors (TLRs) are mammalian homologues of the Drosophila Toll receptors and are thought to have roles in innate recognition of bacteria. We demonstrated that TLR 2, 4, 6, and 8 but not TLR5 were expressed on mouse bone marrow-derived mast cells (BMMCs). Using BMMCs from the genetically TLR4-mutated strain C3H/HeJ, we demonstrated that functional TLR4 was required for a full responsiveness of BMMCs to produce inflammatory cytokines (IL-1beta, TNF-alpha, IL-6, and IL-13) by LPS stimulation. TLR4-mediated stimulation of mast cells by LPS was followed by activation of NF-kappaB but not by stress-activated protein kinase/c-Jun NH2-terminal kinase signaling. In addition, in the cecal ligation and puncture-induced acute septic peritonitis model, we demonstrated that genetically mast cell-deficient W/W(v) mice that were reconstituted with TLR4-mutated BMMCs had significantly higher mortality than W/W(v) mice reconstituted with TLR4-intact BMMCs. Higher mortality of TLR4-mutated BMMC-reconstituted W/W(v) mice was well correlated with defective neutrophil recruitment and production of proinflammatory cytokines in the peritoneal cavity. Taken together, these observations provide definitive evidence that mast cells play important roles in exerting the innate immunity by releasing inflammatory cytokines and recruitment of neutrophils after recognition of enterobacteria through TLR4 on mast cells.
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PMID:Protective roles of mast cells against enterobacterial infection are mediated by Toll-like receptor 4. 1149 12

Polymorphonuclear leukocytes (PMN) and LPS-binding protein (LBP) are both components of the innate immune system. LBP is a plasma protein that binds to lipid A and enhances the biological activity of LPS 100- to 1000-fold. Recently it was reported that LBP-deficient mice are more susceptible to Salmonella typhimurium infection. Here we report that LBP KO mice are more susceptible to Salmonella peritonitis, but not to oral or i.v. infection. LBP knockout (KO) mice responded normally to i.p. injections of Staphylococcus aureus and casein, but not to i.p. injection of S. typhimurium or Salmonella LPS. Mice with a mutation in Toll-like receptor 4 (C3H/HeJ) have a similar defect in PMN chemotaxis. In normal mice S. typhimurium stimulated production of the CXC chemokines macrophage inflammatory protein-2 and cytokine-induced neutrophil chemoattractant, but levels of cytokine-induced neutrophil chemoattractant and macrophage inflammatory protein-2 were greatly reduced in the LBP KO mice. LBP KO mice pretreated with casein to attract PMN in an LBP-independent manner were more resistant to Salmonella infection, but neutropenic mice were not protected by casein. Splenic TNF-alpha mRNA levels were also lower in LBP KO than in control mice infected with Salmonella. Since TNF-alpha can activate PMN, LBP KO mice may have both fewer and less active PMN in the first few hours after Salmonella are injected, making LBP KO mice more susceptible. This work confirms the importance of PMN in resistance to Salmonella infections and shows that this is facilitated by LBP.
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PMID:The role of lipopolysaccharide binding protein in resistance to Salmonella infections in mice. 1205 58

Toll-like receptors (TLRs) are important for the activation of innate immune cells upon encounter of microbial pathogens. The present study investigated the potential roles of TLR2, TLR4, and the signaling protein myeloid differentiation factor 88 (MyD88) in polymicrobial septic peritonitis. Whereas both TLR2 and TLR4 were dispensable for host defense against septic peritonitis, MyD88-deficient mice were protected in this infection model. Recruitment of neutrophils to the septic focus and bacterial clearance were normal in MyD88-deficient mice. In contrast, the systemic inflammatory response was strongly attenuated in the absence of MyD88. Surprisingly, MyD88 deficiency did not alter cytokine and chemokine production in spleen, but markedly reduced the inflammatory response in liver and lung. Production of monocyte chemoattractant protein-1 and macrophage-inflammatory protein-1alpha was entirely independent of MyD88. These results imply a central role of MyD88 for the systemic immune pathology of polymicrobial sepsis and show that cytokine production in spleen and induction of certain chemokines are MyD88 independent.
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PMID:Cutting edge: myeloid differentiation factor 88 deficiency improves resistance against sepsis caused by polymicrobial infection. 1221 91

C57BL/6 and BALB/c mice are prototypical Th1- and Th2-type mouse strains, respectively. In the present study, we attempted to characterize the innate immune response of macrophages from these mouse strains. Macrophages from C57BL/6 mice produced higher levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-12 than those from BALB/c mice after stimulation with macrophage-activating lipopeptide-2 (MALP-2, a synthetic TLR-2 ligand) or lipopolysaccharide (LPS, a TLR-4 ligand). The augmented IL-12 production by C57BL/6 macrophages increased interferon-gamma and, in contrast, decreased IL-13 production by CD4+ T cells. On stimulation with MALP-2 or LPS, C57BL/6 macrophages produced lysosomal enzyme and nitric oxide, effector molecules for bacterial killing, whereas BALB/c macrophages did not. Bactericidal activity of BALB/c macrophages was impaired relative to C57BL/6 macrophages when cells were infected with live bacteria in vitro. In a murine model of septic peritonitis induced by cecal ligation and puncture (CLP), BALB/c mice failed to facilitate bacterial clearance relative to C57BL/6 mice despite an augmented peritoneal leukocyte infiltration that was associated with increased peritoneal levels of cytokines/chemokines. BALB/c mice exhibited increased plasma and hepatic levels of cytokines/chemokines, resulting in an exaggerated systemic inflammation as determined by acute-phase proteins. Finally, BALB/c mice were vulnerable to CLP-induced lethality relative to C57BL/6 mice. Altogether, innate immune response of macrophages is different between these mouse strains, which may affect the development of Th1 and Th2 adaptive immunity in these strains. Reduced systemic inflammatory response in C57BL/6 mice that may result from an eminent local response appears to be beneficial during sepsis.
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PMID:Innate immune response in Th1- and Th2-dominant mouse strains. 1548 39

Toll-like receptors (TLRs) recognize molecular patterns associated with pathogens and initiate various mechanisms that are critical in innate resistance to infection. It has been reported that acute administration of ethanol suppresses responses mediated through TLR3 and TLR4. However, it is not known whether this is also true for other TLRs. Ligands for TLR2/TLR6 (zymosan A), TLR5 (bacterial flagellin), TLR7 (R-848), and TLR9 (CpG DNA) were used to induce cytokine production in mice, and the effects of ethanol (6 g/kg by gavage) on this induction were determined. Because different cell types may be affected differently by ethanol, cytokines were measured in serum (as an indication of cytokines produced by a number of different cell types) and in peritoneal lavage fluid (as an indicator of cytokine production primarily by peritoneal macrophages). Ethanol significantly affected the concentration of at least one of the cytokines evaluated in serum or peritoneal lavage fluid [interleukin (IL)-6, IL-10, and IL-12 p40 subunit] induced by all TLR ligands tested. The results also supported the suggestion that serum and peritoneal cytokines were mostly derived from different cells types, which were affected differently by ethanol. To determine whether ethanol-induced changes in TLR responses were associated with suppression of innate resistance to infection, a model of experimental peritonitis with a nonpathogenic (indigenous) strain of Escherichia coli was developed. Ethanol significantly decreased host resistance to E. coli peritonitis. Thus, ethanol suppresses responses induced by TLR receptors in mice and in the same experimental system it suppresses resistance to infection.
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PMID:Ethanol suppresses cytokine responses induced through Toll-like receptors as well as innate resistance to Escherichia coli in a mouse model for binge drinking. 1552 12

Highly activated neutrophils play a critical role in mediating organ injury in sepsis by releasing neutrophil elastase (NE). Toll-like receptors (TLRs) play an important role in the host defense against invading microbes, and their signaling pathway is critical to the activation of the proinflammatory response. However, the relationship between TLR expression and the host defense mechanism during sepsis has not been fully elucidated. In this paper, we investigated the relationships among chemokine (MIP-2), TLR-4, and NE expression in human sepsis and murine peritonitis (CLP). TLR-4 expression on monocytes/macrophages was examined in patients with sepsis and in murine peritonitis and was markedly increased in both populations. LPS-induced MIP-2 production by bronchoalveolar cells and liver mononuclear cells in mice with peritonitis was also significantly increased compared with sham-operated mice. Pretreatment of the macrophage cell line, RAW 264.7 cells, with a NE inhibitor before their exposure to LPS resulted in a significant dose-dependent decrease in MIP-2 production, which was comparable to that seen following pretreatment with TLR-4 antibody. Furthermore, NE and LPS both up-regulated TLR-4 expression on human peripheral blood monocytes. Thus, chemokine-induced recruitment of neutrophils in sepsis may result in further increased chemokine production and increased expression of TLR-4. Neutrophil-derived NE may be associated with increased expression of monocyte/macrophage TLR-4, thereby serving as a positive feedback loop for the inflammatory response among the different cell populations.
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PMID:Neutrophil elastase, MIP-2, and TLR-4 expression during human and experimental sepsis. 1561 30

Real-time reverse transcriptase polymerase chain reaction (RT rtPCR) was used to quantify the pattern of inflammatory mediator mRNA expression in circulating leukocytes from adult patients diagnosed with severe sepsis. We analysed 29 blood samples from 26 severely septic patients with different septic sources and eight samples from eight healthy adult volunteers. RT rtPCR was used to quantify mRNA expression of 21 different inflammatory mediators in peripheral leukocytes. The median variability in gene expression in the sepsis patients was 10.5 times greater than the variability of the healthy comparison group. We found a significant change in the regulation for the following genes: C5aR (20-fold, P < 0.001), IL-8 (29-fold, P < 0.001), MMP9 (72-fold, P < 0.001), HSP70 (2.4-fold, P = 0.02), and RIP2 (1.8-fold, P < 0.04) were up-regulated. Conversely the median expression of IFNgamma, and IL-6 were zero (P < 0.001), and mtHSP (0.4-fold, P = 0.02) was significantly down-regulated. Using linear discriminant analysis, IFNgamma, IL-12, and TLR4 were correlated to a negative outcome. Different septic sources (peritonitis, burn, pneumonia and musculo-skeletal infections) resulted in significantly different mRNA patterns. The RT rtPCR is a useful tool to monitor the immune response in septic patients. We found a very high variability in inflammatory mediator expression among septic patients compared to healthy volunteers. This suggests that any future immune-modulatory therapy may need to be individualized to the patient's requirements as monitored by RT rtPCR. Different sources of sepsis may result in markedly different activation patterns.
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PMID:The use of real time rtPCR to quantify inflammatory mediator expression in leukocytes from patients with severe sepsis. 1564 82

Scattered evidence suggests that the human peritoneal cavity contains cells of the dendritic cell (DC) lineage but their characterization is missing. Here, we report that the peritoneal cavity of normal subjects and of stable patients on peritoneal dialysis (PD) contains a population of CD14(+) cells that can differentiate into DCs or macrophages. Within this pool, we characterized a CD14(+)CD4(+) cell subset (2.2% of the peritoneal cells) fulfilling the definition of myeloid DC precursors or pre-DC1 cells. These cells expressed high levels of HLA-DR, CD13, CD33, and CD86, and low levels of CD40, CD80, CD83, CD123, CD209, TLR-2 and TLR-4. These cells retained CD14 expression until late stages of differentiation, despite concomitant up-regulation of DC-SIGN (CD209), CD1a, CD80 and CD40. Peritoneal pre-DC1 cells had endocytic capacity that was down-regulated upon LPS/IFN-gamma stimulation, were more potent allo-stimulators than peritoneal CD14(+)CD4(-/lo) cells and monocyte-derived macrophages, and induced Th1 cytokine responses. More importantly, the number of peritoneal pre-DC1 cells increased during PD-associated peritonitis, with a different profile for Gram positive and Gram negative peritonitis, suggesting that these cells participate in the induction of peritoneal adaptive immune responses, and may be responsible for the bias towards Th1 responses during peritonitis.
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PMID:Characterization of human peritoneal dendritic cell precursors and their involvement in peritonitis. 1573 Mar 98

Sepsis results in a state of relative immunosuppression, rendering critically ill patients susceptible to secondary infections and increased mortality. Monocytes isolated from septic patients and experimental animals display a "deactivated" phenotype, characterized by impaired inflammatory and antimicrobial responses, including hyporesponsiveness to LPS. We investigated the role of the LPS/TLR4 axis and its inhibitor, IL-1 receptor-associated kinase-M (IRAK-M), in modulating the immunosuppression of sepsis using a murine model of peritonitis-induced sepsis followed by secondary challenge by intratracheal Pseudomonasaeruginosa. Septic mice demonstrated impaired alveolar macrophage function and increased mortality when challenged with intratracheal Pseudomonas as compared with nonseptic controls. TLR2 and TLR4 expression was unchanged in the lung following sepsis, whereas levels of IRAK-M were upregulated. Macrophages from IRAK-M-deficient septic mice produced higher levels of proinflammatory cytokines ex vivo and greater costimulatory molecule expression in vivo as compared with those of their WT counterparts. Following sepsis and secondary intrapulmonary bacterial challenge, IRAK-M(-/-) animals had higher survival rates and improved bacterial clearance from lung and blood compared with WT mice. In addition, increased pulmonary chemokine and inflammatory cytokine production was observed in IRAK-M(-/-) animals, leading to enhanced neutrophil recruitment to airspaces. Collectively, these findings indicate that IRAK-M mediates critical aspects of innate immunity that result in an immunocompromised state during sepsis.
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PMID:Sepsis-induced suppression of lung innate immunity is mediated by IRAK-M. 1691 41


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