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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endotoxin (lipopolysaccharide [LPS])-induced cytokine release has been implicated in the pathogenesis of sepsis. Sublethal doses of LPS induce tolerance to a septic insult. This study evaluated pretreatment with interleukin 1 (IL-1) against an LPS challenge and examined its relationship to endotoxin tolerance. C3H/HeN mice (N = 100) were injected intraperitoneally with phosphate-buffered saline (control group), IL-1 (200 micrograms/kg), or LPS (1 mg/kg) for 3 days. On day 5, peritoneal macrophages were harvested and assayed for antimicrobial activity (superoxide anion production and Candida albicans phagocytosis). Serum cytokine levels and survival after an LPS challenge on day 5 were also assessed. Pretreatment with IL-1 or LPS significantly increased superoxide anion production, C albicans phagocytosis, and survival compared with pretreatment with phosphate-buffered solution. Interleukin 6 levels significantly decreased in the IL-1 and LPS groups. Peak levels of tumor necrosis factor significantly decreased only in the LPS group. Thus, pretreatment with IL-1 or low doses of LPS may exert protective effects by decreasing levels of interleukin 6 while increasing antimicrobial activity. Mice pretreated with IL-1 were protected from endotoxin despite elevated peak levels of tumor necrosis factor, suggesting a different mechanism for endotoxin tolerance than for tolerance to tumor necrosis factor.
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PMID:Interleukin 1 and its relationship to endotoxin tolerance. 131 50

Macrophage hyperactivity with increased production of tumor necrosis factor, interleukin 6, interleukin 1, and prostaglandins has been demonstrated in the injured patient, but the effect of this on the clinical outcome is unclear. We studied the effect of combination interleukin 1 beta and indomethacin sodium therapy on macrophage hyperactivity and survival after sepsis in a murine burn model. Macrophage interleukin 1, interleukin 6, and tumor necrosis factor alpha production were all significantly increased 10 days after thermal injury. Treatment with recombinant human interleukin 1 beta in combination with indomethacin significantly reduced this overproduction of cytokines to normal levels, and this was associated with an improvement in survival after septic challenge (52% survival in interleukin 1 beta-indomethacin-treated group compared with 22% in burned vehicle control mice). Burned mice that received either interleukin 1 beta or indomethacin alone demonstrated tumor necrosis factor and interleukin 6 production and survival intermediate between the interleukin 1 beta-indomethacin-treated group and the vehicle control group. Control of macrophage hyperactivity is associated with improved survival from subsequent sepsis and offers a potential new strategy for the treatment of immune dysfunction in thermally injured patients.
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PMID:Modulation of macrophage hyperactivity improves survival in a burn-sepsis model. 154 91

Mice were subjected to sepsis by cecal ligation and puncture to determine whether macrophages from endotoxin-tolerant C3H/HeJ mice are also activated systemically to release inflammatory monokines associated with septic mortality. Blood levels of both tumor necrosis factor and interleukin 6 were significantly elevated during the first 1 to 4 hours of sepsis as compared with sham controls. Peritoneal macrophages from septic mice exhibited a marked spontaneous release of interleukin 1, interleukin 6, and tumor necrosis factor at 1 hour. However, the addition of endotoxin to macrophage cultures taken from septic mice had no further stimulatory effect. Sham controls alternatively showed no significant innate monokine release, but their macrophages did release increased monokine numbers in response to endotoxin. These results indicate that the spontaneous macrophage release of these monokines is comparable with that previously observed in endotoxin-sensitive mice, suggesting a common mechanism by which macrophages are primed by traumatic injury by an agent other than endotoxin to release monokines during sepsis. Thus, the administration of agents that decrease or prevent the deleterious effects of systemic inflammatory mediators during sepsis could be useful adjuvants in those clinical situations where the bacterial origin is unknown.
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PMID:Does endotoxin tolerance prevent the release of inflammatory monokines (interleukin 1, interleukin 6, or tumor necrosis factor) during sepsis? 154 97

Stress reactions exist in many conditions in which plasma interleukin 6 (IL-6) is elevated. Examples are burns and sepsis. In these situations fever is often present. These stress situations are always accompanied with high levels of adrenalin and corticosteroids. These hormones, especially when given together, elicit a definite response of acute phase proteins in normal rats. In two stress models, (i) laparotomy and (ii) fever induced by administration of PGE2 in the lateral intracerebral ventricle, we observed a rise of adrenalin and corticosteron followed by an elevated level of plasma IL-6. Therefore, we studied the effect of adrenalin and corticosteron on the plasma level of IL-6. Adrenalin evokes high levels of IL-6, and this effect can be blocked by propranolol. When IL-6 release is blocked in this way, the response of alpha 2 macroglobulin and the cysteine protease inhibitor, both fast-reacting acute phase proteins in rat, is strongly depressed. Isoprenalin, an adreno beta 2 agonist, also causes very high levels of IL-6, indicating that the release of IL-6 can be mediated by an adreno beta 2 receptor whose presence has been demonstrated in monocytic cells. The results suggest a relation between stress situations and IL-6 and may be another factor besides the presence of endotoxins, virus, etc. explaining the high levels of IL-6 observed in many serious clinical situations.
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PMID:The relation among stress, adrenalin, interleukin 6 and acute phase proteins in the rat. 169 83

We investigated the effects of repetitive recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration at three different doses (every 12 h times six doses, starting at 12-24 h of age) on the kinetics of neutrophil production in Sprague-Dawley rats. We determined WBC counts, differentials, the number of total nucleated cells, the myeloid mitotic pool cells (promyelocytes and myelocytes), the storage pool cells (metamyelocytes, bands, and polymorphonuclear cells [PMNs]) and the granulocyte-macrophage (granulocyte-macrophage colony-forming units, CFU-GM) and macrophage (macrophage colony-forming units, CFU-M) progenitor cells of the bone marrow, spleen, and the liver before the first dose of rhG-CSF administration and 12 h after the second, fourth, and sixth dose. Control animals were given the diluent by the same schedule. Recombinant human G-CSF-treated rats showed a significant dose-dependent increase in the number of total WBC and neutrophil counts at all time points compared to control rats. The total number of CFU-GM and myeloid mitotic pool cells (marrow plus spleen plus liver) progressively increased with age in both control and G-CSF groups, but the G-CSF treated groups showed a significantly larger number of mitotic pool cells at hour 24, continuing up to hour 72, compared to the control group. However, there was no significant difference at any time point in the number of CFU-G/GM as detected by the granulocyte-macrophage colony-stimulating factor (GM-CSF)-supported culture system. Priming of newborn rats with injections every 12 h of rhG-CSF times two doses, or six doses followed by inoculation of group B streptococci (GBS) did not significantly change the sepsis death rate of animals, although the neutrophil counts in infected rhG-CSF-primed animals were significantly larger than the infected control animals. Injection of human i.v. gammaglobulin 3 h following inoculation with GBS significantly improved the survival of animals compared to G-CSF administration or administration of the diluent alone (control). Thus G-CSF alone may not be beneficial for the treatment of neonates with sepsis. Additional work is needed to determine whether combination of G-CSF with antibiotics or other cytokines, such as GM-CSF or interleukin 6 (IL-6) may be of benefit.
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PMID:Effect of recombinant human granulocyte colony-stimulating factor administration in normal and experimentally infected newborn rats. 170 9

It has been postulated that Kupffer cells provide signals that regulate hepatocyte responses in sepsis and inflammation. Although in vitro data support such a hypothesis, to our knowledge, no in vivo evidence has been reported. We injected rats with lipopolysaccharide intraperitoneally to simulate sepsis or turpentine intramuscularly to mimic localized inflammation. Both treatments are known to induce the hepatic acute-phase response. Liver nonparenchymal cells and hepatocytes were isolated and placed in culture. Hepatocyte fibrinogen synthesis was measured as an indication of interleukin 6 exposure, while nonparenchymal interleukin 6 production was measured directly. Both lipopolysaccharide and turpentine stimulated a sharp increase in hepatocyte fibrinogen synthesis (turpentine greater than lipopolysaccharide). However, only lipopolysaccharide injection was associated with increased nonparenchymal cell interleukin 6 synthesis. Increased circulating levels of interleukin 6 could be found only after lipopolysaccharide injection. In addition, tumor necrosis factor synthesis was enhanced by lipopolysaccharide but not turpentine. Our data show that nonparenchymal cells are stimulated to provide the interleukin 6 signal to hepatocytes in endotoxemia but not in remote localized inflammation, even though both treatments stimulate the hepatic acute-phase response. Our findings support paracrine functions for liver sinusoidal cells in certain septic states.
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PMID:Liver nonparenchymal cells are stimulated to provide interleukin 6 for induction of the hepatic acute-phase response in endotoxemia but not in remote localized inflammation. 173 48

Increased vasopermeability and vasodilation, presumably the result of endothelial perturbation, are considered among the basic pathogenetic mechanisms in septic shock. Neutrophils have been implicated as a source for mediators in endothelial injury. We measured elastase-alpha 1-antitrypsin (alpha 1AT) complexes and lactoferrin as markers for release of neutrophil granule contents in plasma from patients with sepsis on admission to the Intensive Care Unit, and we delineated the relationship of neutrophil activation to other inflammatory parameters and to hemodynamic and biochemical parameters. Levels of elastase-alpha 1AT and lactoferrin significantly correlated with each other (r = 0.58; p less than 0.008), and were increased (greater than 3.33 and 5 nmol/L, respectively) in 96% and 71% of the patients, respectively. Lactoferrin, but not elastase-alpha 1AT, correlated with the number of white blood cells (r = 0.38; p = 0.008). Elastase-alpha 1 AT levels were significantly higher (p = 0.008), whereas white blood cell counts were lower (p = 0.015) in patients with shock when compared with patients without abnormal blood pressure. Both elastase-alpha 1AT and lactoferrin levels correlated with lactate levels (r = 0.33; p = 0.024 and r = 0.30; p = 0.04), suggesting a role for neutrophil activation in the pathogenesis of hypoxygenation. In addition, elastase-alpha 1AT correlated with the concentrations of interleukin 6 (IL-6) (r = 0.46; p = 0.001) and C3a (r = 0.38; p = 0.009), suggesting that cytokines and complement may contribute to the degranulation of neutrophils in sepsis. Elastase-alpha 1AT complexes were inversely related to C1-inhibitor (r = -0.33; p = 0.028) and to platelet numbers (r = -0.42; p = 0.003). Levels of elastase-alpha 1AT complexes in plasma appeared to be of prognostic significance; levels were higher in 27 patients who died than in 21 patients who survived (p = 0.01). The mortality in 27 patients with concentrations below 10 nM was 37%, whereas it was 81% in 21 patients with higher levels. The overall mortality in this study was 56%. These results provide further evidence that activation and degranulation of neutrophils, induced by multiple agonists, are involved in the development of fatal complications in patients with sepsis.
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PMID:Plasma elastase alpha 1-antitrypsin and lactoferrin in sepsis: evidence for neutrophils as mediators in fatal sepsis. 174 Jun 29

We studied the plasma levels of the acute phase mediator interleukin 6 (IL-6) in 21 severely burned patients (burn injuries ranging from 24% to 75% total body surface area). The posttraumatic course of the IL-6 plasma levels was closely related to the clinical outcome. The nonseptic survivors as well as survivors with suspected sepsis (n = 14) exhibited maximal amounts of IL-6 (251 +/- 32 pg/mL) during the first 3 days post-burn, which subsequently returned to values within the normal range (days 30 to 50; 26 +/- 8 pg/mL). In the nonsurvivors (n = 7) IL-6 concentrations permanently increased (up to 1,921 +/- 356 pg/mL) until death (days 10 to 19) resulting from sepsis with consecutive multiple organ failure. Peripheral blood mononuclear cells (PBMCs) of patients expressed IL-6-specific mRNA in vivo at high levels in contrast to the PBMCs of healthy donors. In addition, the spontaneous and PHA-induced in vitro production of IL-6 by patients' PBMCs was enhanced compared with healthy controls, whereas no significant differences were obtained with bacterial endotoxin (LPS). The findings suggest that interleukin 6 is a potential mediator of lethal sepsis after major thermal trauma.
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PMID:Interleukin 6--a potential mediator of lethal sepsis after major thermal trauma: evidence for increased IL-6 production by peripheral blood mononuclear cells. 174 40

Endotoxin (lipopolysaccharide [LPS]) and tumor necrosis factor (TNF-alpha) have been implicated in the pathogenesis of sepsis-induced adult respiratory distress syndrome. To evaluate the possible interaction of the hepatic-pulmonary macrophage axis in the adult respiratory distress syndrome, we compared the kinetics of immunosuppressive prostaglandin E2, TNF-alpha, and interleukin 6 production in LPS-stimulated Kupffer cells and alveolar macrophages (AMs). Interleukin 6 production by Kupffer cells was significantly higher than for equal numbers of AMs. Kupffer cell TNF-alpha levels peaked early before decreasing as regulatory prostaglandin E2 levels rose. In contrast, AM TNF-alpha levels rose sharply and remained significantly higher than for Kupffer cells throughout culture coincident with negligible prostaglandin E2 production. Kupffer cell sequestration of LPS may normally invoke a coordinated cytokine response able to locally induce acute-phase hepatocytes. In hepatic failure, however, LPS spillover to the lung may promote adult respiratory distress syndrome by inducing unregulated AM TNF-alpha production within the pulmonary microenvironment.
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PMID:Organ interactions in sepsis. Host defense and the hepatic-pulmonary macrophage axis. 198 33

Endotoxemia was evoked by bolus injection of Escherichia coli endotoxin (2 ng/kg body weight) in six healthy subjects to investigate the early kinetics of cytokine release in relation to the development of clinical and hematologic abnormalities frequently seen in gram-negative septicemia. The plasma concentration of tumor necrosis factor (TNF) increased markedly after 30 to 45 minutes, and reached a maximal level after 60 to 90 minutes. In each volunteer, the initial increase of plasma interleukin 6 (IL-6) concentrations occurred 15 minutes after the initial TNF increase, and maximal IL-6 concentrations were reached at 120 to 150 minutes. A transient increase in body temperature and pulse rate occurred simultaneously with the initial TNF and IL-6 increases, whereas a significant decrease in blood pressure occurred after 120 minutes. These changes were proportional to the changes in TNF and IL-6 concentrations. Coagulation activation, as assessed by a rise of prothrombin fragments and thrombin-antithrombin III complexes, was noted after 120 minutes, in the absence of activation of the contact system. A two- to sixfold increase in the concentrations of tissue plasminogen activator (t-PA) and von Willebrand factor antigen indicated endothelial cell activation. This increase started at 120 and 90 minutes, respectively. The release of t-PA coincided with activation of the fibrinolytic pathway, as measured by plasmin-alpha 2-antiplasmin complexes. The fibrinolytic activity of t-PA was subsequently offset by release of plasminogen activator inhibitor, observed 150 minutes after the endotoxin injection, and reaching a peak at 240 minutes. No complement activation was detected. These results show that in humans endotoxin induces an early, rapidly counteracted fibrinolytic response, and a more long-lasting activation of thrombin by a mechanism other than contact system activation. In addition, our data suggest that endotoxin-induced leukopenia and endothelial cell activation are mediated by TNF.
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PMID:Experimental endotoxemia in humans: analysis of cytokine release and coagulation, fibrinolytic, and complement pathways. 212 34


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