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)

The vasodilator bradykinin (Bk) has long been though to participate in shock induced by endotoxemia, anaphylaxis and acute pancreatitis. Recently developed kinin antagonists have made it possible to test this hypothesis. We studied the effect of two of them. DArg0Hyp3-Thi5.8-DPhe7-Bk (45 and 220 micrograms/kg/min) and Lys-Lys-Hyp2-Thi5.8-DPhe7-Bk (100 micrograms/kg/min) on the early hypotensive response to Escherichia coli lipopolysaccharide (LPS). Rats infused with the antagonist vehicle were used as controls. At 45 micrograms/kg/min, DArg0-Hyp3-Thi5.8-dPhe7-Bk prevented the hypotensive response to high doses of Bk; however, neither antagonist prevented the hypotensive response to LPS. Circulating kinins measured 3 min after injecting LPS or vehicle were similar (16.3 +/- 1.4 vs. 26.0 +/- 7.2 pg/ml; P greater than .23). In allergically sensitized rats, 500 micrograms/kg/min DArg0-Hyp3-Thi5.8-DPhe-7-Bk did not alter the hypotensive (anaphylactic) response to antigen challenge (P greater than .38). Similarly, hypotension caused by development of acute pancreatitis in rats was not prevented by infusion of DArg0-Hyp3-Thi5.8-DPhe7-Bk at 200 micrograms/kg/min, 10 min) (P greater than .69). These results indicate that in the rate formation of kinins is not a major contributor to the hypotensive response observed in early endotoxemia, anaphylaxis and acute pancreatitis.
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PMID:Kinin antagonist does not protect against the hypotensive response to endotoxin, anaphylaxis or acute pancreatitis. 281 Jan 21

The problem of whether human pancreatic phospholipase A2 (PLA2) can really hydrolyze membrane phospholipids in vitro was studied to understand pathophysiology of acute pancreatitis. Total amount of lysophospholipids generated in erythrocytes by exogenously added human pancreatic PLA2 (2 micrograms/ml) was only 12% of the amount of sphingomyelin, which was not decomposed by the enzyme. About fivefold the amount of lysophospholipids was generated in ghost membranes during one-sixth of the incubation time compared to that in intact erythrocyte membranes. Escherichia coli lipopolysaccharide (LPS) (10 micrograms/ml) was able to stimulate membrane-associated PLA2 of erythrocytes, the amount of lysophospholipids generated being 12.5% of that of sphingomyelin without adding the exogenous PLA2. The stimulation of membrane-associated PLA2 in erythrocytes was inhibited by pretreatment of lipopolysaccharide with polymyxin-B sulfate. When intact erythrocytes were incubated with human pancreatic PLA2 and LPS, the amount of generated lysophospholipids was 24% of that of sphingomyelin. These results suggested that the exogenously added human pancreatic PLA2 cannot degrade phospholipids of intact erythrocytes so extensively under physiological conditions, and, in acute pancreatitis, unknown factors may be involved in the hydrolysis of phospholipids. LPS, which activates membrane-associated PLA2, may be one of the factors, and thus membrane phospholipids are hydrolyzed in the disease.
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PMID:Hydrolytic activities of human pancreatic phospholipase A2 and endotoxin-stimulated endogenous phospholipase A2 toward membrane phospholipids of erythrocytes. 388 99

Severe acute pancreatitis is often complicated by intraperitoneal infection, resulting in multiple organ failure (MOF). It is known to elevate serum tumor necrosis factor (TNF-alpha) in patients with sepsis and/or MOF. In order to study the role of TNF-alpha in the aggravation of acute pancreatitis, we investigated TNF-alpha production by peritoneal macrophages in acute pancreatitis rat using the cerulein-induced pancreatitis model. TNF-alpha production by isolated peritoneal macrophages following lipopolysaccharide (LPS) stimulation was significantly increased in pancreatitis rats as compared with nonpancreatitis control rats (p < 0.001). Serum TNF-alpha activity was elevated following intraperitoneal administration of LPS as the septic challenge both in pancreatitis rats and in control rats, being significantly higher in the former (p < 0.05). Histological findings and liver function tests revealed that LPS induced more severe liver damage in pancreatitis rats than in control rats within 24 h after LPS administration. These results indicate that increased TNF-alpha production by peritoneal macrophages in acute pancreatitis augmented LPS-induced liver injury and suggest the possibility that TNF-alpha may play a role in the development of MOF during acute pancreatitis complicated by intraabdominal sepsis.
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PMID:The role of tumor necrosis factor-alpha in the aggravation of cerulein-induced pancreatitis in rats. 828 75

The effects of pancreatic secretory trypsin inhibitor (PSTI) on cerulein-induced pancreatitis were studied in a rat model. Arg44 of PSTI was replaced by Ser using site-directed mutagenesis (R44S-PSTI). R44S-PSTI has a longer half-life than the natural form. Pancreatitis was induced by four intramuscular injections of cerulein (50 microgram/kg at 1 h intervals). Continuous intravenous infusion of R44S-PSTI began at a dose of 20 micrograms/kg/h 30 min before the first cerulein injection, and was completed 3 h after the last cerulein injection. Tumour necrosis factor (TNF-alpha) production by isolated peritoneal macrophages from rats with cerulein-induced pancreatitis increased following lipopolysaccharide stimulation, compared to control rats (P < 0.01). R44S-PSTI administration significantly decreased the TNF-alpha production by peritoneal macrophages from rats with cerulein-induced pancreatitis (P < 0.05). In addition, R44S-PSTI significantly reduced serum amylase activity (P < 0.01) and pancreatic wet weight after pancreatitis induction (P < 0.05). Histological examination revealed marked acinar cell vacuolization, interstitial oedema, and cellular infiltration in cerulein-induced pancreatitis, but a lesser degree of histological change in rats that were treated with R44S-PSTI. Prophylactic use of intravenous R44S-PSTI infusion may reduce the severity of acute pancreatitis either histologically or serologically.
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PMID:The protective effects of long-acting recombinant human pancreatic secretory trypsin inhibitor (R44S-PSTI) in a rat model of cerulein-induced pancreatitis. 867 1

The role of the hypothalamic-pituitary-adrenal axis (HPA axis) in acute pancreatitis has not yet been clarified. In the present study, the concentrations of serum corticosterone and amylase, the severity of pancreatic edema, and the histology of the pancreas during cerulein-induced pancreatitis were compared in two strains of rats whose HPA axes have been reported to be hyperresponsive (Fischer female) and hyporesponsive (Lewis female) to inflammatory mediators. First, we confirmed that the secretory response of corticosterone to lipopolysaccharide was remarkably blunted in Lewis rats compared with Fischer rats. With a single intraperitoneal injection of cerulein at a dose of 50 micrograms/kg, the serum corticosterone of Fischer rats increased promptly, and their serum levels were significantly higher than those of Lewis rats at all points after the induction of pancreatitis. The edema formation and infiltration of inflammatory cells into the pancreas were more severe in Lewis rats than in Fischer rats. The serum amylase concentration was not significantly different between the two strains, except at 2 h after the induction of pancreatitis. The in vitro study using dispersed pancreatic acini showed that there was no significant difference in cerulein-stimulated amylase secretion between the two strains. These findings suggest that the responsiveness of the HPA axis and the consequent secretion of glucocorticoids might modify the pathological features of acute pancreatitis.
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PMID:The role of pituitary-adrenal counterregulation of inflammation in cerulein-induced pancreatitis: a comparison between Fischer and Lewis rats. 883 Mar 35

Nitric oxide (NO) has been shown to play a significant role in inflammation. To clarify the role of NO in acute pancreatitis, we investigated the serum concentrations of NO chi (NO2- plus NO3-) and tumor necrosis factor-alpha (TNF-alpha) and the grade of pancreatitis in cerulein-induced pancreatitis in mice pretreated with lipopolysaccharide (LPS) or not. LPS pretreatment aggravated the cerulein pancreatitis in association with a transient increase in serum TNF-alpha, which was followed by a gradual elevation of serum NO chi. This elevation of serum NO chi concentration was inhibited by the NO synthase inhibitor NG-nitro-L-arginine (L-NNA). In addition, the activity of NADPH-diaphorase (NADPH-d), a marker for NO synthase, appeared in the peritoneal macrophages of LPS-pretreated mice after the induction of pancreatitis. No elevation of serum NO chi or appearance of NADPH-d activity in peritoneal cells was found in mice without LPS pretreatment. Administration of L-NNA enhanced the elevation of pancreatitis-induced serum amylase in mice untreated with LPS, while L-NNA inhibited the elevation in LPS-pretreated mice. The effects of L-NNA were reversed by the administration of L-arginine but were not affected by D-arginine. These results suggested that (a) inflammatory cells may not be fully activated to produce excessive NO in uncomplicated edematous pancreatitis, and (b) edematous pancreatitis may be aggravated by excessively produced NO if bacterial infection is complicated and inflammatory cells are activated to express inducible NO synthase.
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PMID:The role of nitric oxide in mouse cerulein-induced pancreatitis with and without lipopolysaccharide pretreatment. 892 22

We investigated the effects of the xanthine derivative propentofylline on lung injury in rats with cerulein-induced acute pancreatitis and endotoxemia. Pancreatitis was induced by four intramuscular injections of cerulein (50 micrograms/kg at 1-h intervals). Pancreatitis rats were injected intraperitoneally with 30 mg/kg lipopolysaccharide (LPS) 6 h following the first cerulein injection as a septic challenge. Propentofylline (50 mg/kg) was injected intravenously 15 min before the administration of LPS. Rats were divided randomly into five experimental groups: group I, normal rats; group II, pancreatitis; group III, LPS injection; group IV, pancreatitis and LPS injection; and group V, pancreatitis and LPS injection with propentofylline pretreatment. Serum amylase concentrations in groups II, IV, and V increased significantly 8 h after the first cerulein injection compared to those in groups I and III. Serum tumor necrosis factor (TNF)-alpha concentrations, cytokine-induced neutrophil chemoattractant (CINC) concentrations in serum or bronchoalveolar (BAL) fluid, lung myeloperoxidase (MPO) activity, and extent of pulmonary polymorphonuclear cell infiltration in group IV were significantly higher than those observed in group III. Pretreatment with propentofylline inhibited the rise in TNF-alpha levels (group V). However, propentofylline did not prevent the elevation of CINC levels in group V. In contrast, propentofylline reduced lung MPO and pulmonary PMN infiltration in group V. In addition, lung compliance was improved by pretreatment with propentofylline. These results suggest that propentofylline attenuates lung injury in an experimental model of pancreatitis complicated by endotoxemia but has differential effects on cytokine production.
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PMID:Effects of propentofylline on tumor necrosis factor-alpha and cytokine-induced neutrophil chemoattractant production in rats with cerulein-induced pancreatitis and endotoxemia. 909 57

Oxidative stress and the inflammatory response may play roles in the pathogenesis of acute pancreatitis. Herein, we characterized pancreatic expression of oxidative stress-responsive genes [c-fos, heme oxygenase-1 (HO-1), and metallothionein-I (MT-I)] and cytokine genes [interleukin-1 beta (IL-1 beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha)] during caerulein-induced acute pancreatitis in the mouse. c-fos, HO-1, and MT-I mRNAs were coordinately and rapidly (3-7 h) upregulated, and HO-1 and MT-I protein levels were increased slightly in the pancreas during acute pancreatitis. In addition, IL-1 beta, IL-6, and TNF-alpha mRNAs were rapidly (7 h) upregulated in the pancreas, and intrapancreatic IL-1 beta and IL-6 protein levels rapidly increased (3-fold and 6.4-fold, respectively) during acute pancreatitis. These studies suggest that oxidative stress and inflammation each occur in the pancreas during the early stages of acute pancreatitis. However, under a limited set of experimental conditions, we found that an insult that causes pancreatic oxidative stress (diethylmaleate) or one that induces an inflammatory response (bacterial lipopolysaccharide), or a combination of these agents, did not cause the changes characteristic of acute pancreatitis. Therefore, simply inducing oxidative stress and/or inflammation may be insufficient to initiate acute pancreatitis.
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PMID:Expression of oxidative stress-responsive genes and cytokine genes during caerulein-induced acute pancreatitis. 931 74

Hepatic dysfunction is one of the critical complications in acute pancreatitis but this mechanism is poorly understood. In patients with acute pancreatitis, hypoalbuminemia is often recognized, suggesting possible disturbance of hepatic transport of proteins and hepatic metabolites. The present study was undertaken to elucidate hepatic function in cerulein-induced pancreatitis from the viewpoint of intrahepatic vesicular transport. We examined the biliary excretion of lipopolysaccharide (LPS), whose pathway in the hepatocyte has been shown to be microtubule dependent. In vivo studies and ex vivo studies using isolated perfused rat liver (IPRL) showed that cumulative excretion of LPS in each period was significantly reduced, by 49 and 25%, respectively, compared with that in control rats. But studies of biliary secretion in vivo and ex vivo studies indicated statistical insignificance between the two groups. Moreover, biliary excretion of LPS was inhibited to 60% of the control by colchicine pretreatment, without affecting bile flow in IPRL, but gadolinium chloride had no effect. We conclude that transport of LPS across the hepatocyte from blood to bile is impaired in rats with cerulein-induced pancreatitis without being affected by Kupffer cell function. These results suggest that a disturbance of vesicular transport in hepatocyte may also occur in exocytosis and endocytosis via the sinusoidal membrane, cause impairment of hepatic transport of proteins and hepatic metabolites, and result in hepatic dysfunction in acute pancreatitis.
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PMID:Impaired transport of lipopolysaccharide across the hepatocytes in rats with cerulein-induced experimental pancreatitis. 951 Jan 37

A severe acute pancreatitis was produced by intraperitoneal injection of lipopolysaccharide (LPS) in rats with preexisting hemorrhagic and necrotizing pancreatitis induced by retrograde injection of a 5% taurocholate plus 1% trypsin solution into the pancreatic duct. Mortality and time-course changes in pancreatic, hepatic, renal and pulmonary functions, and organ myeloperoxidase (MPO) levels were examined in this model. LPS at an intraperitoneal dose of 30 mg/kg, which scarcely caused death and had no marked effect on serum parameters and organ MPO levels in rats without pancreatitis, increased the mortality in rats with taurocholate plus trypsin-induced pancreatitis. Pancreatic weight and ascitic volume increased in rats with taurocholate plus trypsin-induced pancreatitis regardless of the presence or absence of LPS. Serum amylase and lipase levels were also significantly increased in rats with induced pancreatitis, but was higher in the group given LPS. Serum glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), blood urea nitrogen (BUN) and creatinine levels were significantly elevated in LPS-treated rats with induced pancreatitis, whereas levels in rats with induced pancreatitis not given LPS were only slightly elevated. Renal weight was also significantly increased in rats with induced pancreatitis despite the presence or absence of LPS. In LPS-treated rats with induced pancreatitis, the arterial oxygen pressure, pulmonary weight and pulmonary MPO level were significantly elevated. However, the MPO level in the kidney in these rats was not different from that in control rats, indicating that the renal dysfunction was not produced by the infiltration of neutrophils into the kidney. Increase in the pancreatic MPO level was observed in rats with induced pancreatitis, but combination treatment with LPS did not raise it. Protective effects of prophylactic treatment of 2-(3-methylsulfonylamino-2-oxo-6-phenyl-1,2-dihydro-1-pyridyl)-N-( 3,3,3-trifluoro-1-isopropyl-2-oxopropyl)acetamide (compound 1), a neutrophil elastase inhibitor, and trifluoroacetyl-L-lysyl-L-alaninanilide hydrochloride (compound 2), a pancreatic elastase inhibitor, on mortality were also examined in this model. Results were compared with that of the combined treatment of compound 1 and compound 2. In LPS-treated rats with taurocholate plus trypsin-induced pancreatitis, the combined treatment of compound 1 (2 mg/kg/h) and compound 2 (30 mg/kg/h) significantly reduced mortality, whereas single treatment of compound 1 or compound 2 did not show the beneficial effect. These results suggest that marked hepatic and renal dysfunction accompanies pancreatitis in this pancreatitis model rats, which may be good models for acute pancreatitis in humans. It is also suggested that neutrophil and pancreatic elastases may be synergistically involved in the pathogenesis of acute pancreatitis in this model.
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PMID:Protective effect of the combined treatment of pancreatic and neutrophil elastase inhibitors on acute pancreatitis elicited by lipopolysaccharide in rats given intraductal injection of taurocholate plus trypsin. 965 Aug 10


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