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Query: UMLS:C0243026 (
sepsis
)
52,417
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Despite recent advances in antibiotic therapy, aggressive operative intervention and intravenous hyperalimentation,
sepsis
, and multiple organ failure are still reported to contribute to significant morbidity and mortality in the surgical intensive care unit. In light of this, it is essential to determine the mechanism underlying the pathophysiology of
sepsis
so that better therapeutic interventions can be designed. Experimental studies indicate that murine polymicrobial
sepsis
induces a marked suppression in both lymphocytic and macrophage function associated with decreased cellular adenosine triphosphate levels and increased Ca2+. However, such changes are not detectable until approximately 12 h after the onset of
sepsis
. Alternatively, early (0-4 h) in
sepsis
, macrophages from the liver and peritoneum exhibit augmented innate secretion of proinflammatory cytokines, tumor necrosis factor, interleukin (IL)-6, and IL-1, associated with the systemic release of these agents. Sustained release of immunosuppressive agents transforming growth factor-beta, IL-4, IL-10, and
PGE2
, as well as glucocorticoids, are also observed during
sepsis
. In this regard, many investigators, including us, have suggested that an agent(s) released as a part of this systemic inflammatory response to
sepsis
may be responsible for the protracted suppression of immune cell function. Studies examining the effects of these mediators in vitro on various immune cells have shown that many of these agents also have the capacity to induce a process referred to as programmed cell death (PCD) or apoptosis (Ao). We have presented evidence of marked changes in the rate of Ao in immune cells after the onset of
sepsis
. These data suggest the possibility that mediators released in response to septic insult contribute to the observed changes in immune cell function through the induction of Ao. Inasmuch, understanding the contribution of PCD to the pathophysiology of
sepsis
, should provide a better basis from which to develop more effective therapy for the septic patient.
...
PMID:Immune dysfunction in murine polymicrobial sepsis: mediators, macrophages, lymphocytes and apoptosis. 882 95
Colchicine has been shown to act as an antiinflammatory agent. In this study, we examined whether colchicine and other microtubule-depolymerizing drugs affected the production of TNF-alpha. When rat peritoneal macrophages were stimulated by LPS, addition of colchicine, vincristine, vinblastine or nocodazole was found to inhibit TNF-alpha release in a concentration-dependent manner. Suppression of TNF-alpha release was not due to interference with secretion as the cytokine did not accumulate intracellularly following colchicine treatment. Colchicine markedly enhanced
PGE2
release from LPS-stimulated macrophages. However, addition of the cyclooxygenase inhibitor indomethacin only partially reversed the suppressive effect of colchicine on TNF-alpha production. Colchicine caused a strong reduction of LPS-induced TNF-alpha mRNA accumulation, suggesting that a pretranslational effect may represent the primary mechanism by which colchicine reduced TNF-alpha production. These observations could have clinical relevance in ameliorating undesirable effects due to excessive TNF-alpha production, for example following LPS stimulation of monocytes/macrophages in gram-negative
sepsis
. Furthermore, these drugs may provide useful tools to study the apparent involvement of the microtubular system in cytokine gene expression and cytokine production.
...
PMID:Inhibition of LPS-induced tumor necrosis factor-alpha production by colchicine and other microtubule disrupting drugs. 893 62
Inflammatory bowel disease is associated with mucosal neutrophil recruitment and activatation, mediated in part by arachidonic acid metabolites. G-CSF attenuates the immune response to
sepsis
and ameliorates glycogen storage disease Ib-related colitis. These actions may be effected through the shedding of neutrophil adhesion molecules, or inhibition of proinflammatory mediator synthesis. Immune complex colitis was used to evaluate the effect of rhG-CSF on colonic mucosal inflammation, neutrophil recruitment and the generation of eicosanoids. Immune complex colitis was induced in White New Zealand rabbits. Animals were pretreated with rhG-CSF either 24 h before induction, or at induction, with dosages of 50 and 200 micrograms/kg. rhG-CSF caused a time- and dose-dependent neutrophilia in all animals. Pretreatment with rhG-CSF resulted in increased tissue myeloperoxidase levels, despite a histologically similar mucosal polymorphonuclear cell infiltrate between treated and control colitis groups. Leukotriene B4 (LTB4) and thromboxane B2 (TXB2) dialysis fluid levels were lower in treated animals, in particular in the groups receiving two doses (LTB4: both P < 0.01; TXB2: both P < 0.01.
Prostaglandin E2
(
PGE2
) levels in dialysis fluid of the rhG-CSF-treated animals showed no difference from controls. In this model of experimental colitis, high-dose therapy with G-CSF resulted in a marked decrease of proinflammatory mediators, but mucosal generation of the protective
PGE2
was preserved. These results suggest that prolonged high-dose therapy with G-CSF may have anti-inflammatory effects in colitis.
...
PMID:Efficacy of recombinant granulocyte colony-stimulating factor (rhG-CSF) in experimental colitis. 897 23
Decreases in the alveolar O2 tension commonly follow gram-negative bacteremic shock that progresses to the acute respiratory distress syndrome (ARDS). To examine the effects of alveolar hypoxia and reoxygenation (H/R) on postbacteremic pulmonary cytokine expression, lungs from Sprague-Dawley rats (n = 43) were perfused over 180 min after hematogenous infection with 10(9) live Escherichia coli serotype O55:B5 (EC) or infusion of 0.9% NaCl (NS). Compared with normoxic EC and NS controls, EC + H/R and NS + H/R lungs received 90 min of constant-flow hypoxia followed by 60 min of reoxygenation. Perfusates were cultured and analyzed for TNF-alpha, IL-1alpha, IL-1beta, and
PGE2
while monitoring pulmonary artery pressure (Ppa). Changes in the filtration coefficient (Kf) were evaluated at 180 min when cytokine mRNA levels were assessed in lung homogenates. Transcripts of the anti-inflammatory cytokine TGF-beta1 and of inducible cyclooxygenase (COX-2) were similarly analyzed. For equivalent EC clearance, Ppa, and Kf as in normoxic EC, postbacteremic H/R increased TNF-alpha gene expression and doubled the export of TNF-alpha from the lungs, an effect not blocked by allopurinol. IL-1alpha transcripts were also increased in EC + H/R versus EC lungs, in contrast to the lack of change in IL-1beta, TGF-beta, or COX-2 mRNA levels, or in cell-associated or circulating IL-1beta and
PGE2
. Thus, gram-negative bacteremic lung infection and secondary alveolar H/R upregulate the expression of specific inflammatory cytokines compared with pulmonary infection under normoxic conditions, independently of xanthine oxidase-induced O2 radicals. These findings identify the alveolar PO2 as a potent immunomodulatory signal whose reductions early after gram-negative
sepsis
may enhance lung inflammation in ARDS.
...
PMID:Upregulation of postbacteremic TNF-alpha and IL-1alpha gene expression by alveolar hypoxia/reoxygenation in perfused rat lungs. 947 82
Prostaglandin E2
(
PGE2
) has been implicated in the suppression of T cell IL-2 production and proliferation during burn and
sepsis
. The present study evaluated the potential intracellular mechanism of suppressed T cell responses by assessing the activation of p59fyn kinase in T cells from septic rats as well as the T cells incubated with
PGE2
. p59fyn is known to regulate T cell functions.
Sepsis
was induced in rats by implanting fecal pellets containing Escherichia coli (150 CFU) and Bacteroides fragilis (10(4) CFU) into the abdominal cavity. For the assessment of
PGE2
role in
sepsis
, a group of septic rats were treated with indomethacin, which inhibits endogenous
PGE2
synthesis. As assessed by immunoblotting or in vitro kinase assay, a more than 40% inhibition of p59fyn phosphorylation and kinase activity was observed in septic rat T cells compared with the T cells from sterile or control rats. A similar inhibition in p59fyn phosphorylation and kinase activity was observed in
PGE2
-treated T cells compared with the T cells incubated in the absence of
PGE2
. The septic-related suppression in p59fyn phosphorylation and kinase activity in T cells was prevented in rats treated with indomethacin. We observed that the inhibition in p59fyn activation in septic or
PGE2
-treated T cells was due primarily to a suppression in p59fyn phosphorylation and not due to alterations in p59fyn protein expression. These findings suggest that
PGE2
released during
sepsis
could contribute to the
sepsis
-related suppression in T cell proliferation by attenuating p59fyn phosphorylation and its kinase activity.
...
PMID:Prostaglandin E2 modulation of p59fyn tyrosine kinase in T lymphocytes during sepsis. 955 31
The production of pro-inflammatory cytokines, such as interleukins 1 and 6 and tumour necrosis factors, occurs rapidly following trauma or invasion of the body by pathogenic organisms. The cytokines mediate the wide range of symptoms associated with trauma and infection, such as fever, anorexia, tissue wasting, acute phase protein production and immunomodulation. In part, the symptoms result from a co-ordinated response, in which the immune system is activated and nutrients released, from endogenous sources, to provide substrate for the immune system. Although the cytokine mediated response is an essential part of the response to trauma and infection, excessive production of pro-inflammatory cytokines, or production of cytokines in the wrong biological context, are associated with mortality and pathology in a wide range of diseases, such as malaria,
sepsis
, rheumatoid arthritis, inflammatory bowel disease, cancer and AIDS. Cytokine biology can be modulated by antiinflammatory drugs, recombinant cytokine receptor antagonists and nutrients. Among the nutrients, fats have a large potential for modulating cytokine biology. A number of trials have demonstrated the anti-inflammatory effects of fish oils, which are rich in n-3 polyunsaturated fatty acids, in rheumatoid arthritis, inflammatory bowel disease, psoriasis and asthma. Animal studies, conducted by ourselves and others, indicate that a range of fats can modulate pro-inflammatory cytokine production and actions. In summary fats rich in n-6 polyunsaturated fatty acids enhance IL1 production and tissue responsiveness to cytokines, fats rich in n-3 polyunsaturated fatty acids have the opposite effect, monounsaturated fatty acids decrease tissue responsiveness to cytokines and IL6 production is enhanced by total unsaturated fatty acid intake. There are a large number of potential cellular mechanisms which may mediate the effects observed. The majority relate to the ability of fats to alter the composition of membrane phospholipids. As a consequence of alterations in phospholipid composition, membrane fluidity may change, altering binding of cytokines to receptors and G protein activity. The nature of substrate for various signalling pathways associated with cytokine production and actions may also be changed. Consequently, alterations in eicosanoid production and activation of protein kinase C may occur. We have examined a number of these potential mechanisms in peritoneal macrophages of rats fed fats with a wide range of fatty acid composition. We have found that the total C18:2 and 20:4 diacyl species of phosphatidylethanolamine in peritoneal macrophages relates in a positive curvilinear fashion with dietary linoleic acid intake; that TNF induced IL1 and IL6 production relate in a positive curvilinear fashion to linoleic acid intake; that leukotriene B4 production relates positively with dietary linoleic acid intake over a range of moderate intakes and is suppressed at high intakes, while
PGE2
production is enhanced. There was no clear relationship between linoleic acid intake and membrane fluidity, however fluidity was influenced in a complex manner by the type of fat in the diet, the period over which the fat was fed and the presence of absence of TNF stimulation. None of the proposed mechanisms, acting alone, can explain the positive effect of dietary linoleic acid intake on pro-inflammatory cytokine production. However each may be involved, in part, in the modulatory effects observed.
...
PMID:Modulation of pro-inflammatory cytokine biology by unsaturated fatty acids. 955 30
Prostaglandin E2
(
PGE2
) is significantly elevated in the plasma of septic or injured patients and is thought to be a component of the resultant immune suppression associated with augmented rates of infection and mortality. Many studies have examined the effect of burn injury and
sepsis
on
PGE2
synthesis. However, the effect of
sepsis
or burn injury on the expression of prostaglandin 15-hydroxydehydrogenase (PGDH), the key enzyme responsible for
PGE2
degradation, has not been explored. The aim of this study was to examine the effect of endotoxin treatment and/or burn injury on the expression of PGDH. Male BDF1 mice were assigned to four groups (n = 4/group): sham, lipopolysaccharide (LPS) (2.5 mg/kg, Escherichia coli LPS, i.p.), burn (15% body surface area scald injury), and burn + LPS (15% body surface area + 2.5 mg/kg LPS, i.p.). Lung tissue was harvested at specific time points after treatment and subsequently was processed for total RNA and protein. Northern and Western blot analyses were used to examine differences in PGDH protein and mRNA expression. Total RNA was probed with the riboprobe for murine PGDH, and the 100,000 g protein fraction was immunoblotted using an rabbit antimurine PGDH antibody. PGDH was expressed in lung at t = 0 in both the saline and LPS-treated animals. A decrease in mRNA expression was initially observed at 2 hours after LPS treatment. The decrease was also significant (p < 0.05) at 3 hours after LPS and maximal decrease in mRNA and protein expression was observed at 6 hours. At 24 hours after LPS administration, the PGDH mRNA and protein expression was still significantly depressed to 49% of control expression. PGDH expression was similar and not statistically different in both burn and burn + LPS treatment at t = 0. At 2 hours after LPS, PGDH mRNA expression in the burn + LPS treatment group had significantly decreased to 47% in comparison with the burn alone group. Maximal decrease in PGDH mRNA and protein expression in lung from burn + LPS was observed at 6 hours after LPS treatment. This change represents a 73% decrease in mRNA in comparison with the time-matched burn control. At 24 hours after LPS administration, PGDH mRNA but not protein expression in the lung from burn + LPS treated mice was still significantly decreased. In summary, LPS treatment alters PGDH mRNA expression at the transcriptional and protein levels. Consequently,
sepsis
-induced increases in
PGE2
levels may not be only due to increased
PGE2
synthesis but also due to decreased PGDH expression and, hence,
PGE2
degradation.
...
PMID:Prostaglandin E2 alterations during sepsis are partially mediated by endotoxin-induced inhibition of prostaglandin 15-hydroxydehydrogenase. 960 77
We investigated the effect of 16,16-dimethyl prostaglandin E2 indomethacin and Ginkgo biloba extract on the survival in two experimental
sepsis
models in rats due to administration of 1 x 10(7) cfu and 1 x 10(9) cfu Escherichia coli. Animals in each model were then randomly divided (10/group) into four groups, administered saline, indomethacin, G. biloba extract and prostaglandin E2 respectively. When compared, there was no significant difference in the survival period between the two
sepsis
models (P > 0.05). The best survival rate was observed in the
PGE2
-administered animals in the first major model (P < 0.05). Indomethacin appeared not to decrease the mortality rates. There was no significant difference in
PGE2
levels between two
sepsis
models (P > 0.05). Our results suggest that elevated prostaglandin E2 levels following major trauma are not responsible for the postinjury increased susceptibility to infectious complications. Our observations should also discourage aggressive use of cyclo-oxygenase inhibitors for protection against infectious complications after major trauma.
...
PMID:The effects of prostaglandin E2 indomethacin & Ginkgo biloba extract on resistance to experimental sepsis. 979 34
These serial clinical and experimental studies were designed to clarify the pathogenesis of postburn MODS. Both animal and clinical studies were performed. In animal experiments, 46 male cross-bred dogs were cannulated with Swan-Ganz catheters and 39 of them were inflicted with 50% TBSA third degree burns (7 were used as controls). The burned dogs were randomly divided into 4 groups: immediate infusion, delayed infusion, delayed fast infusion and delayed fast infusion combined with ginsenosides. All dogs were kept under constant barbiturate sedation during the whole study period. Hemodynamics, visceral MDA, mitochondrial respiratory control rate (RCR) and ADP/O ratio, ATP, succinic dehydrogenase (SDH), organ water content as well as light and electron microscopy of visceral tissues were determined. In the clinical study, 61 patients with extensive deep burns were chosen, of which 16 sustained MODS. Plasma TXB2/6-keto-PGF1alpha ratio, TNF, SOD, MDA, circulatory platelet aggregate ratio (CPAR),
PGE2
, interleukin-1, total organ water content and pathological observations of visceral tissues from patients who died of MODS were carried out. Results demonstrated that ischemic-reperfusion damage due to severe shock,
sepsis
and inhalation injury are three main causes of postburn death. All inflammatory mediators increased markedly in both animals and patients who sustained organ damage or MODS. SDH, RCR, ADP/O and ATP decreased significantly. These findings suggested that ischemic damage and systemic inflammatory response syndrome (SIRS) initiated by mediators or cytokines might be important in the pathogenesis of postburn MODS.
...
PMID:Serial experimental and clinical studies on the pathogenesis of multiple organ dysfunction syndrome (MODS) in severe burns. 991 70
The present study ascertained the role of
PGE2
in
sepsis
associated modulation of IL-2 and IL-10 production by T cells.
Sepsis
was induced in 225-250 g male rats (Sprague Dawley) by implanting fecal pellets containing Escherichia coli (100-150 CFU) and Bacteroides fragilis (10(4) CFU) into the abdominal cavity. Animals implanted with fecal pellets without the bacteria were designated as sterile. For the assessment of
PGE2
role in
sepsis
, a group of septic and sterile rats were pretreated with indomethacin to inhibit endogenous
PGE2
synthesis. Splenic T cells were obtained 48 h after septic or sterile implantations, and their IL-2 and IL-10 production was measured. A significant suppression in the levels of IL-2 production and mRNA expression was observed in T cells from septic rats compared with the T cells from sterile and control rats. IL-10 protein and mRNA expression was found to be significantly higher in septic rat T cell compared to sterile and control rat T cells. Although, treatment of animals with indomethacin significantly prevented the
sepsis
-related suppression of IL-2 production, such treatment of animals was associated with a further upregulation of IL-10 production. These data suggest that although
PGE2
released during
sepsis
can cause T cell IL-2 down-regulation, it may not mediate the T cell IL-10 upregulation. The IL-2 down-regulation may not be an effect of IL-10 upregulation.
...
PMID:Prostaglandin E2 down-regulation of T cell IL-2 production is independent of IL-10 during gram-negative sepsis. 1023 94
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