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Query: UMLS:C0001339 (acute pancreatitis)
 10,593 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phospholipase A2 (PLA2) has been postulated to play an important role in the pathogenesis of acute pancreatitis. To study the mechanism through which PLA2 may cause cellular damage, we used an in vitro model of isolated rat pancreatic acini prepared by collagenase digestion. Newly synthesized proteins were labeled by [35S]methionine. Cellular destruction was measured by the degree of release of radiolabeled proteins. Incubation of pancreatic acini with PLA2 alone caused only minor damage when very high concentrations of this enzyme were used. However, when acini were incubated with PLA2 in combination with its substrate, lecithin, cells were destroyed in a time- and concentration-dependent manner. Incubating cells with pancreatic homogenates and lecithin caused damage only when there had been prior activation of homogenates with either trypsin or enterokinase. The damage could be simulated by incubating acini with pure lysolecithin. Alcohol and cerulein did not further increase the destruction caused by PLA2 and lecithin. When acini were incubated with supernatants from another set of acini to which oleic acid had been added, a similar degree of damage resulted as compared with acini incubated with oleic acid alone. However, adding PLA2 to supernatants from acini preincubated with fatty acids significantly increased the degree of cellular necrosis. The destruction by PLA2 and lecithin was inhibited by albumin but could not be inhibited by gabexate mesilate, nafamostat mesilate, or cytidine diphosphocholine. We conclude that PLA2 could play a role in pancreatic acinar cell damage, especially in the spread of cellular necrosis within the organ, provided that its substrate, lecithin, is present.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of phospholipase A2 in pancreatic acinar cell damage and possibilities of inhibition: studies with isolated rat pancreatic acini. 841 11

Phospholipase A2 (PLA2) is a group of secretory as well as intracellular enzymes that release phospholipids as an early step in inflammation and play a physiologic role in digestion. In humans, the group of secretory, low-molecular-weight PLA2 (sPLA2) is differentiated from the cytosolic, high-molecular-weight PLA2 (cPLA2). The two known cPLA2 mediate the intracellular response to inflammation by releasing arachidonic acid from membrane phospholipids. Secretory pancreatic PLA2 (sPLA2-I) is a digestive zymogen secreted from pancreatic acinar cells in its inactive form. Activated by trypsin in the duodenum, it is an important digestive enzyme. In acute pancreatitis, circulating sPLA2-I indicates pancreatic injury but is mostly inactive. Synovial-type secretory PLA2 (sPLA2-II), first isolated from synovial fluid of arthritis patients, is increased in inflammation, after surgery or trauma, and in various inflammatory diseases. Unlike sPLA2-I, its catalytic activity is held responsible for mediating the systemic inflammatory reaction and its complications by regulating the synthesis of prostaglandins, leukotrienes and platelet activating factor. Clinically, sPLA2-II offers new possibilities as an early marker for severe inflammation and predicting systemic complications in severely ill patients.
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PMID:[Phospholipase A2--from basic research to clinical reality]. 951 1

Phospholipase A2 has been suggested to be involved in the pathogenesis and pathophysiology of acute pancreatitis. We determined phospholipase A2 and amylase activities in duodenal juice collected during a secretin test from 30 consecutive patients who were suspected to have chronic pancreatitis or biliary disease. The patients underwent endoscopic retrograde cholangiopancreatography (ERCP) the following day. In the 8 patients with ERCP findings of advanced chronic pancreatitis, the mean outputs of phospholipase A2, amylase, and bicarbonate were reduced by 74%, 72%, and 60% compared to the respective values in the 13 (control) patients without a diagnosis of any pancreatic disorder or jaundice. In the 3 patients with recurrent pancreatitis but normal ERCP findings and in the 6 patients with jaundice the output values were not significantly reduced compared to those in the patients without any pancreatic disorder or jaundice. The outputs of amylase and phospholipase A2 were not significantly interrelated, whereas the outputs of phospholipase A2 and bicarbonate correlated well. Receiver characteristic (ROC) curves confirmed the high specificity and sensitivity of phospholipase A2 or bicarbonate output in patients with ERCP findings of advanced chronic pancreatitis compared to those with no changes in pancreatic ducts, with similar probability values of 0.880 +/- 0.111 (SEM), compared to the respective lower value of amylase, 0.676 +/- 0.118. Phospholipase A2 and bicarbonate output proved of equal value as markers of chronic pancreatitis and were superior to amylase output in the secretin test.
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PMID:Duodenal secretion of phospholipase A2, amylase, and bicarbonate in chronic pancreatitis. 960 59

Phospholipase A2 has been implicated in the pathogenesis and pathophysiology of acute pancreatitis. The initial enthusiasm concerning pancreatic group I phospholipase A2 as an enzyme responsible for pancreatic necrosis and systemic manifestations of acute pancreatitis has gradually waned, as the mechanisms of the pathogenesis and the pathophysiology of acute pancreatitis have been revealed. The overactive systemic inflammatory response associated with the activation of different cascade systems and increased levels of inflammatory mediators as seen in severe acute pancreatitis, closely resembles that associated with other severe inflammatory diseases such as septic shock. The critical role of the non-pancreatic secretory group II phospholipase A2 in the chain of inflammatory mediators has been emphasized recently, as new detection methods for the enzyme have become available.
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PMID:Phospholipase A2 in acute pancreatitis: new biochemical and pathological aspects. 1057 38

Phospholipase A2 (PLA2) has been suggested to play an important role in the pathogenesis of acute pancreatitis, in part through the PLA2-generated phospholipid by-products, most notably lysophosphatidylcholine (lyso-PC). The effects of lyso-PC on pancreatic acinar cells, other than the induction of necrosis, are poorly characterized. Here we examined the effects of lyso-PC on the induction of apoptosis in rat pancreatic AR42J cells. Lyso-PC induced apoptosis in a dose-dependent manner at 10 and 25 microM, but induced cell lysis at > or = 50 microM. Lyso-PC-induced (at 25 microM) apoptosis was not blocked by a protein kinase C inhibitor (staurosporine) or by inhibitors of caspases (acetyl-DEVD-aldehyde and benzoyloxycarbonyl-VAD-fluoromethylketone). Lyso-PC at 10 and 25 microM induced the expression of clusterin mRNA and wild-type p53. Apoptosis induction by lyso-PC (at 25 microM) was not inhibited by a specific antagonist of platelet-activating factor (PAF) receptor, suggesting that the action was independent of th
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PMID:Lysophosphatidylcholine induces apoptosis in AR42J cells. 1113 76

Phospholipase A2 (PLA2) has been suggested in the pathogenesis of acute pancreatitis, in part through the PLA2-generated phospholipid by-products, most notably lysophosphatidylcholine (lyso-PC). The effects of lyso-PC on pancreatic acinar cells other than necrosis are poorly characterized. Recent studies have suggested a role of the activation of transcription factors such as nuclear factor kappa B (NF-kappaB) for the pathogenesis of acute pancreatitis. Here we examined the effects of lyso-PC on the activation of transcriptional factors in rat pancreatic AR42J cells. Lyso-PC induced apoptosis at concentrations > or = 10 microM. At 10 and 25 microM, lyso-PC increased the NF-kappaB- and activator protein-1 (AP-1)-specific DNA binding activity as determined by electrophoretic mobility shift assay. Lyso-PC also increased the transcriptional activity of NF-kappaB and AP-1 as assessed by luciferase assay. Lyso-PC increased the mRNA level of pancreatitis-associated protein-I and c-jun. Lyso-PC activated three classes of mitogen activated protein kinases: extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase/stress-activated protein kinase and p38 kinases. Activation of transcription factors by lyso-PC was not altered by a specific platelet activating factor receptor antagonist, TCV-309, suggesting that the activation was independent of the platelet activating factor receptor. These molecular events may suggest a novel role of lyso-PC for the modulation of acinar cell function.
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PMID:Lysophosphatidylcholine activates transcription factor NF-kappaB and AP-1 in AR42J cells. 1157 38

The effects of stable prostacyclin analogue iloprost on the trypsinogen activation, labilization of lysosomal membranes, lipolytic enzymes activities, histopathological and ultrastructural changes in the pancreas of rats with severe, taurocholate acute pancreatitis (AP), preceded for 6 h by acute ethanol intake have been investigated. Iloprost (1 microg/kg b.w., i.p.) was applied every 6 hours after inducing of taurocholate AP. The antecedent intragastric 40% ethanol intake (5 g/kg b.w.) increased an index of trypsinogen activation in AP lasting 18 h. Treatment with iloprost prevented this increase in the rats with AP given earlier alcohol, and limited the labilization of lysosomal membranes in nonalcoholized rats with AP. Phospholipase A2 and lipase activities were reduced by iloprost only in the rats not given ethanol. The additional damaging effect of acute ethanol abuse prior to AP could be dependent on augmented activation of trypsinogen. The protective effect of iloprost in AP seems to be dependent on the attenuation of trypsinogen activation, decrease of total potential trypsin and the decrease of lysosomal membranes labilization. Its protective effect could be limited in taurocholate acute pancreatitis preceded by acute ethanol intake as evidenced by the differences in the cathepsin B, phospholipase A2 and lipase activities and by histopathological and ultrastructural examination.
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PMID:Beneficial effect of iloprost on the course of acute taurocholate pancreatitis in rats and its limitation by antecedent acute ethanol intake. 1508 42

Proinflammatory cytokines are elevated during acute pancreatitis. The endotoxins and Phospholipase A2 (PLA2) also have important role in acute pancreatitis. The aim of this study was to determine, what factors are responsible for the tissue damage in acute pancreatitis. The examinations were performed on fixed and frozen sections of healthy dog's pancreas tissue. Direct effects of endotoxins, PLA2, and proinflammatory cytokines together with pancreas enzymes were examined on pancreatic tissue. Pancreas enzymes themselves did not cause any change in the structure of pancreas. The common influence of endotoxins, PLA2 and pancreas enzymes was examined, and finally the effect of proinflammatory cytokines and enzymes was examined on pancreas tissue. Our results show, that besides enzymes many other factors are necessary to inflict tissue damage in acute pancreatitis, but for necrosis the presence of TNF alfa is a must.
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PMID:[In vitro examination of the influence of lipase and amylase on dog's pancreas tissue incubated with endotoxins, phospholipase A2 or cytokines]. 1601 80

Continuous hemodiafiltration (CHDF) has been performed for the treatment of severe acute pancreatitis. Phospholipase A2 (PLA2) is one of the important mediators which exacerbate acute pancreatitis, but whether PLA2 can be removed by CHDF is unclear. In this study, the kinetics of group IB and group IIA PLA2 was examined at the first session of low-volume CHDF in eight patients with severe acute pancreatitis. CHDF was performed using polysulfone hemofilters (surface area: 0.7 m(2)) at a blood flow rate of 100 mL/min and a filtration and dialysate flow rate of 10 mL/min each. The plasma concentrations of group IB and IIA PLA2 before the start of CHDF were 47.4 +/- 52.0 microg/L and 352 +/- 390 microg/L, respectively, and did not change significantly. The clearances of group IB and IIA PLA2 achieved by the CHDF circuit 1 h after the start of CHDF were 20.7 +/- 11.6 mL/min and 16.7 +/- 4.4 mL/min, respectively, with both clearances decreasing significantly with time. The clearance of group IB PLA2 into the waste fluid tended to increase with time; however, the concentrations of group IIA PLA2 in the waste fluid were less than the measurable sensitivity. These results indicate that group IB PLA2 is adsorbed on the hemofilter membrane in preference to being removed into the waste fluid, while group IIA PLA2 is mainly removed by adsorption. However, low-volume CHDF is not effective at eliminating the group IB and IIA PLA2 plasma concentration.
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PMID:Kinetics of group IB and IIA phospholipase A2 during low-volume continuous hemodiafiltration in severe acute pancreatitis. 1747 Feb 10


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