Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endogenous opioids have been reported to elicit some of the pathophysiologic responses to endotoxic shock by binding to the delta-opiate receptor. We have previously reported the production of immunoreactive (ir)-endorphin by B lymphocytes treated with bacterial lipopolysaccharide (LPS). We postulated that this lymphocyte-derived ir-endorphin may be an extrapituitary source of the endogenous opioid component associated with the pathophysiology of endotoxic shock. To test this hypothesis, we chose to study the LPS-sensitive (C3HeB/FeJ) and -resistant (C3H/HeJ) inbred mouse model. We treated these mice with intraperitoneal injections of LPS or B-lymphocyte-derived ir-endorphin. The LPS-sensitive mice presented with a severe hypothermic and pathophysiologic response pattern when treated with LPS or with ir-endorphin. The LPS-resistant mice, which were unresponsive to the LPS, however, presented with the typical hypothermic and pathophysiologic responses to the ir-endorphin. Immunofluorescence on the splenic leukocytes in the LPS-treated mice showed significant ir-endorphin present only in the LPS-sensitive mice at a time point preceding onset of the pathophysiologic response pattern. Taken together, this evidence strongly suggests a role for B-lymphocyte-derived ir-endorphin in the pathophysiology of endotoxic shock. The implications of immune system regulation of neuroendocrine function are discussed.
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PMID:Splenic lymphocyte production of an endorphin during endotoxic shock. 333 Jun 73

The effects of pretreatment with prostaglandin E2 or the platelet-activating factor antagonist, CV-3988, on endotoxin-induced gastric damage, gastrointestinal plasma protein leakage, and systemic hypotension were examined in the rat. Endotoxic shock was induced by intravenous administration of lipopolysaccharide from Escherichia coli and was characterized by prolonged hypotension, gastrointestinal hyperemia and hemorrhage, and marked leakage of radiolabelled albumin into the interstitium and lumen of the gastrointestinal tract. Prostaglandin E2 (25-100 micrograms/kg i.v.) dose-dependently inhibited the hypotension and gastric damage induced by endotoxin. At the dose tested, CV-3988 (10 mg/kg i.v.) also significantly reduced endotoxin-induced hypotension and gastric damage. Both prostaglandin E2 (50 micrograms/kg) and CV-3988 reduced endotoxin-induced plasma protein leakage into the interstitium and lumen of the gastrointestinal tract, although there were differences in terms of the regions most affected by the two compounds. The results of the present study suggest that prostaglandin E2 and CV-3988 may have acted via a similar mechanism, possibly involving inhibition of a mediatory role of platelet-activating factor in endotoxic shock.
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PMID:Gastrointestinal plasma leakage in endotoxic shock. Inhibition by prostaglandin E2 and by a platelet-activating factor antagonist. 347 14

Endotoxemia is a frequent complication of many health disorders. It is characterized by systemic release of a variety of endogenous inflammatory mediators which effect cardiovascular depression, reductions in organ blood flow, tissue ischemia and derangements in cellular metabolism leading to death. During a continuous intravenous infusion of Escherichia coli lipopolysaccharide, the chronology of alterations in hepatosplanchnic blood flow, hepatic carbohydrate metabolism and pancreatic insulin secretion has been studied in awake Yucatan miniature pigs (Sus scrofa). Endotoxic shock in this model is characterized by reductions in portal venous and hepatic arterial blood flow, early transient increases in pancreatic insulin secretion, increases in the 3H-glucose-derived rates of glucose appearance and disappearance, profound hypoglycemia, hyperlactatemia and metabolic acidosis. Reductions in hepatic oxygen delivery are compensated for by enhanced oxygen extraction efficiency, but hepatic gluconeogenesis continues at an inadequate rate to compensate for increased glucose utilization. Experimental therapies including lidocaine, naloxone, captopril, dichloroacetate and glucagon each effect specific improvements in cardiovascular or metabolic function, but none significantly alter the composite derangements responsible for lethality in this model.
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PMID:Endotoxemia in Yucatan miniature pigs: metabolic derangements and experimental therapies. 353 41

Although some data suggest that macrophages in the reticuloendothelial system (RES) are important sources of thromboxane A2 (TxA2) and prostacyclin (PGI2) during endotoxic shock, we are unaware of data documenting the ability of hepatic macrophages (Kupffer cells) to release either TxA2 or PGI2 when exposed to lipopolysaccharide (endotoxin, LPS). In this study, Kupffer cells were examined for their ability to release prostaglandin E2 (PGE2), TxA2, and PGI2 following stimulation with 0, 1.0, 50.0, and 100.0 micrograms/ml of Escherichia coli LPS. Kupffer cells were obtained from rat livers by enzymatic digestion with 0.05% collagenase followed by enrichment of the macrophage population on the basis of differences in density and adherence among the various cell populations isolated. Based on several criteria (phagocytosis of opsonized sheep erythrocytes, positive staining for esterase and peroxidase, failure to replicate), 95% of adherent cells were Kupffer cells. After 4 days of incubation, cells were stimulated with various doses of LPS for 4 and 8 hr. Prostanoid concentrations in culture supernatants were determined by radioimmunoassay. Increasing doses of LPS significantly (P less than 0.001) increased the concentration of immunoreactive PGE2 (iPGE2) and iTxB2 (the stable metabolite of TxA2). The concentration of i6-keto-PFG1 alpha (stable metabolite of PGI2) increased following stimulation with 1.0 microgram/ml of LPS, but declined as the dose of LPS was increased. The results provide evidence that endotoxin-activated Kupffer cells, like other macrophage populations, release several metabolites of arachidonic acid. Kupffer cell-derived prostanoids, particularly TxA2, may be important mediators of some of the pathophysiologic manifestations of acute endotoxemia.
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PMID:Prostanoid production by lipopolysaccharide-stimulated Kupffer cells. 388 37

When Escherichia coli B6 lipopolysaccharide, 0.2 mg/kg of body weight, was infused into nonpregnant minipigs during a 5-hour period, the animals died after 12 to 16 hours as a result of endotoxic shock. When the same infusion was given to six pregnant minipigs at term, these animals died after only 3 1/2 hours. The decrease in the number of white blood cells, the number of platelets, hematocrit, and clotting factors was not significantly different between the two groups. The acid-base status, however, indicated a much more pronounced metabolic acidosis in the pregnant animals than in the nonpregnant controls. In the pregnant minipigs heart rate, cardiac output, mean arterial pressure, and total peripheral resistance indicated cardiovascular collapse, and the multiple wire, platinum surface electrode revealed a drastic reduction in uterine tissue oxygenation in the pregnant animals. The data support the hypothesis that pregnant animals at term are more susceptible to the harmful effects of lipopolysaccharide. Early death in the pregnant minipigs, however, was not associated with disseminated intravascular coagulation as it is in smaller animals (rat, rabbit, and hamster).
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PMID:Septicemia during pregnancy: a study in different species of experimental animals. 392 Sep 12

The incorporation of 14C-palmitate into various classes of tissue lipids by isolated adult dog heart myocytes was studied in an attempt to understand the pathophysiology of myocardial dysfunction during endotoxic shock. The results showed that the incorporation of 14C-palmitate into phospholipids was increased by 85.3% and 108.8% at 0.5 hours and two hours, respectively, following endotoxin (0.5 mg Escherichia coli lipopolysaccharide B per kg body weight) administration. Incorporation of radioactive palmitate into triglycerides was increased by 50.9% and 107.2% at 0.5 and two hours, respectively, postendotoxin. Incorporation of 14C-palmitate into diglycerides was stimulated by 51.9% and 64.5% at 0.5 and two hours, respectively, after endotoxin injection. The incorporation of 14C-palmitate into tissue-free fatty acids and unaltered at 0.5 hours but it was increased by 211.7% at two hours postendotoxin. These data demonstrated that myocardial membrane lipid profile was greatly altered by increased incorporation of 14C-palmitate into phospholipids and neutral lipids after endotoxin administration. An alteration in myocardial lipid profile, as reported in this study, may contribute to the development of myocardial dysfunction during shock.
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PMID:Increased incorporation of 14C-palmitate into tissue lipids by isolated heart myocytes in endotoxic shock. 675 37

Endotoxic shock is associated with a coagulopathy, organ failure, and death. Tissue factor (TF) expression by monocytes exposed to bacterial endotoxin (lipopolysaccharide [LPS]) may mediate the coagulopathy and contribute to the high mortality of this disease. We examined the role of the LPS-binding protein (LBP)/CD14 receptor pathway in the LPS induction of TF expression in human monocytic THP-1 cells and peripheral blood monocytes. In THP-1 cells, the threshold concentration of LPS required to induce TF activity in serum-free medium was reduced 20-fold by purified LBP, which also enhanced TF mRNA synthesis. Similarly, monocytes cultured in the presence of serum were induced to express TF antigen at LPS concentrations 100 times lower than monocytes cultured in serum-free medium. An anti-LBP monoclonal antibody indicated that this effect was dependent on the presence of LBP in serum. LPS/LBP induction of TF activity and TF antigen expression in these monocytic cells were also inhibited by an anti-CD14 monoclonal antibody, indicating a requirement for the CD14 receptor. Thus, we suggest that low levels of LPS (5 to 100 pg/mL) present during sepsis induce TF expression in monocytes via the LBP/CD14-dependent pathway.
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PMID:Role of the lipopolysaccharide (LPS)-binding protein/CD14 pathway in LPS induction of tissue factor expression in monocytic cells. 751 85

1. Endotoxin induces a shock-like syndrome with increased nitric oxide synthesis. To clarify the cellular source of NO in endotoxic shock we used immunohistochemistry and in situ hybridization to localize inducible NO synthase in rats given lipopolysaccharide or Corynebacterium parvum and lipopolysaccharide. Immunohistochemistry was carried out with an antibody raised against a synthetic peptide of mouse macrophage NO synthase. In situ hybridization was performed with 35S-labelled oligonucleotide probes corresponding to cDNA sequences common to mouse macrophage inducible NO synthase and rat vascular smooth inducible NO synthase. Monocytes and macrophages were identified by immunohistochemistry with the mouse monoclonal antibody ED1. 2. After lipopolysaccharide alone, the major site of NO synthase induction was monocytes and macrophages in multiple organs, principally liver and spleen. Bronchial, bile duct, intestinal and bladder epithelium and some hepatocytes also expressed inducible NO synthase. Expression peaked at 5 h and had returned to normal by 12 h except in spleen. 3. After priming with C. parvum, lipopolysaccharide led to a similar distribution of inducible NO synthase as lipopolysaccharide alone, but in addition there was more prominent hepatocyte staining, staining in macrophage granulomas in the liver and inducible NO synthase was present in some endothelial cells in the aorta. 4. These findings provide a direct demonstration of the cellular localization of inducible NO synthase after lipopolysaccharide.
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PMID:Cellular localization of inducible nitric oxide synthase in experimental endotoxic shock in the rat. 752 18

An antirat monoclonal antibody (mAb) against inducible nitric oxide synthase (iNOS), ANOS11, was used for immunohistochemistry to examine the expression of iNOS in various organs and tissues of adult rats in experimental endotoxic shock induced by lipopolysaccharide (LPS) injection. The phenotype of iNOS-expressed cells was also examined immunohistochemically using various mAbs. In control rats, very few cells were positive for ANOS11 except in the thymus. After intravenous injection of LPS, the number of iNOS-positive cells increased rapidly in almost all organs, except the thymus and brain, peaked 6 h after the injection, and decreased slowly. Of the numerous inflammatory cells that infiltrated the lungs, liver, and spleen after LPS injection, many were positive for ANOS11. Besides inflammatory cells, hepatocytes and endothelial cells of the aorta were also positive for ANOS11 but only around 6 h after injection. The cellular composition of iNOS-positive infiltrated cells changed along with the progression of endotoxic shock. At 4 to 6 h after injection, most iNOS-positive cells were considered polymorphonuclear leukocytes judging by their positive reactivity to OX42 and their nuclear morphology. The population of iNOS-positive macrophages positive for ED1 or ED2 increased with time. After 24 h, many iNOS-positive macrophages were found around the focal necrosis in the liver and spleen. These results indicate that the expression of iNOS in neutrophils, endothelial cells, and hepatocytes precedes that of macrophages in experimental endotoxic shock. The expression of iNOS in various cells and organs is closely associated with the progress and pathological changes of endotoxic shock.
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PMID:Immunohistochemical expression of inducible nitric oxide synthase (iNOS) in reversible endotoxic shock studied by a novel monoclonal antibody against rat iNOS. 753 Feb 82

Administration of Escherichia coli lipopolysaccharide (LPS; 10 mg/kg i.v.) to male Wistar rats caused within 240 min (i) a sustained fall (approximately 30 mmHg) in mean arterial blood pressure, (ii) a reduction (> 75%) in the pressor responses to norepinephrine (1 microgram/kg i.v.), and (iii) an induction of nitric oxide synthase (iNOS) as measured in the lung. Dexamethasone (1 mg/kg i.p. at 2 h prior to LPS) attenuated the hypotension and the vascular hyporeactivity to norepinephrine and reduced (by approximately 77%) the expression of iNOS in the lung. These effects of dexamethasone were prevented by pretreatment of LPS-treated rats with a neutralizing antiserum to lipocortin 1 (anti-LC1; 60 mg/kg s.c. at 24 h prior to LPS) but not by a control nonimmune sheep serum. Stimulation of J774.2 macrophages with LPS (1 microgram/ml for 24 h) caused the expression of iNOS and cyclooxygenase 2 (COX-2) protein and significantly increased nitrite generation; this was prevented by dexamethasone (0.1 microM at 1 h prior to LPS), which also increased cell surface lipocortin 1. Pretreatment of J774.2 cells with anti-LC1 (1:60 dilution at 4 h prior to LPS) also abolished the inhibitory effect of dexamethasone on iNOS expression and nitrite accumulation but not that on COX-2 expression. A lipocortin 1 fragment (residues 1-188 of human lipocortin 1; 20 micrograms/ml at 1 h prior to LPS) also blocked iNOS in J774.2 macrophages activated by LPS (approximately 78% inhibition), and this too was prevented by anti-LC1. We conclude that the extracellular release of endogenous lipocortin 1 (i) mediates the inhibition by dexamethasone of the expression of iNOS, but not of COX-2, and (ii) contributes substantially to the beneficial actions of dexamethasone in rats with endotoxic shock.
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PMID:Lipocortin 1 mediates the inhibition by dexamethasone of the induction by endotoxin of nitric oxide synthase in the rat. 753 34


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