血小板激活因子在急性重症胰腺炎发 病过程中作用的实验研究

作者为探讨血小板激活因子在狗急性重症胰腺炎发病过程中的作用，采用１７只比格（Ｂｅａ－ｇｌｅ）狗，随机分为三组：对照组（ｎ＝５）、胰腺炎组（ｎ＝６）、治疗组（ｎ＝６）。胰腺炎组及治疗组动物制成急性重症胰腺炎动物模型。治疗组动物在模型复制后５ｍｉｎ，３ｈ分别静脉注射血小板激活因子（ＰＡＦ）拮抗剂ＢＮ５２０２１（５ｍｇ／ｋｇ）。用温氏法测定血清淀粉酶活性，血小板聚集法测定血清及胰腺组织中ＰＡＦ的含量。结果显示：急性重症胰腺炎模型复制成功后３０ｍｉｎ，胰腺炎组血清淀粉酶活性即上升到基础值的２００±４４．７％，８ｈ高达４６６．７±１１１．６％。８ｈ时与对照组、治疗组差异均有显著性意义（Ｐ＜０．０５）。胰腺炎组血中ＰＡＦ含量在３０ｍｉｎ时即开始上升，８ｈ达最高１１．８１±０．７８ｎｇ／ｍｌ，在３０ｍｉｎ之后与对照组比较即差异有非常显著的意义（Ｐ＜０．０１），而１ｈ之后与治疗组差异有非常显著的意义（Ｐ＜０．０１）。胰腺组织中ＰＡＦ含量，胰腺炎组比治疗组及对照组明显增高（Ｐ＜０．０１）。作者认为ＰＡＦ在急性重症胰腺炎的发病过程中起重要作用，ＰＡＦ拮抗剂有希望成为治疗急性重症胰腺炎的有效药物。     

Effect of platelet-activating factor antagonists (BN-52021, WEB-2170, and BB-882) on bacterial translocation in acute pancreatitis

Bacterial translocation is an important source of pancreas infection in acute pancreatitis. The effect of platelet-activating factor (PAF) in the pathogenesis of acute pancreatitis has been proved in various studies. The aim of this study was to determine whether potent PAF antagonists influence bacterial translocation in acute pancreatitis. Acute pancreatitis was induced in 62 Wistar rats by injection of 2.5% sodium taurocholate into the biliopancreatic duct. The rats treated with PAF factor antagonists received intravenous injection of WEB-2170 (10 mg/kg), lexipafant (5 mg/kg), and BN-52021 (5 mg/kg) 30 minutes before induction of acute pancreatitis. Six hours after induction of acute pancreatitis, bacteriologic cultures and histologic scoring of tissues were performed. There was a statistically significant reduction in bacterial translocation to the mesenteric lymph nodes and liver but not to the pancreas of the rats treated with PAF antagonists. No significant increase in the intestinal bacterial population of any group was found. There were no statistical differences between the pancreatic histologic scores of the groups. PAF antagonists reduced bacterial translocation to distant sites other than the pancreas, preventing the bacterial dissemination that occurs in the early phase of acute pancreatitis and may have beneficial effects on the evolution of this disease.     

Platelet-activating factor antagonists do not attenuate delayed posttraumatic cerebral edema in rats

Platelet-activating factor (PAF) receptor antagonists reportedly improve early postischemic neurological recovery and cerebral blood flow in selected experimental models. Their effects on posttraumatic cerebral edema have, however, not been examined. In a rat model of right hemispheric percussive cerebral trauma, we examined the effects of two PAF receptor antagonists on posttraumatic edema formation. Two groups of rats received either BN 52021 (n = 14) or WEB 2086 (n = 11), 10 mg/kg i.v. at 15 min posttrauma. Two other groups treated with the BN 52021 (n = 17) and WEB 2086 (n = 10) vehicles served as controls. Hemispheric percent brain water was determined at 24 h. Edema occurred in all groups. Neither PAF receptor antagonist significantly reduced right hemispheric percent brain water (81.08 +/- 0.25 and 81.04 +/- 0.15 in Bn 52021 and WEB 2086-treated rats, respectively, versus 81.31 +/- 0.23 and 81.14 +/- 0.17% brain water in BN 52021 vehicle and WEB 2086 vehicle-treated rats). Mortality was not statistically different between groups. These data do not support a major role for PAF in the development of posttraumatic cerebral edema.     

Long-term lung preservation with the PAF antagonist BN 52021

Platelet activating factor (PAF, 1-alkyl-2(R)-acetyl-glycero-3- phosphorylcholine) is a phospholipid that is released by a variety of cells. The similarity between the pathophysiological effects of PAF and posttransplant pulmonary dysfunction led to an evaluation of a PAF antagonist as an adjunct to lung preservation. The ginkgolide B, BN 52021, was selected as the PAF antagonist to be studied because of the large data base available on this compound. BN 52021 was given to the donor and recipient (10 mg/kg i.v.) prior to harvest and transplantation and was included in 1 L of preservation solution (10 mg/kg) used for flushing the pulmonary artery and for storage. Left single-lung transplantation was performed following a 22-hr preservation period at 10 degrees C. Arterial oxygen tension (pO2), pulmonary vascular resistance (PVR), alveolar arterial oxygen difference (A-aDO2), and dynamic lung compliance (DLC) were recorded for 6 hours following ligation of the native pulmonary artery. At the end of 6 hr pO2 was 243.5 +/- 61.5 vs. 71.7 +/- 10.2 mmHg (P less than 0.02) for the controls. A-aDO2 was less in the BN 52021 groups: 431.8 +/- 58.3 vs. 606.0 +/- 9.8 mmHg in the control groups (P less than 0.001), and PVR was significantly less in the BN 52021 group: 346 +/- 70.8 vs. 663 +/- 64.3 dynes/sec/cm-5 (P less than 0.035). We conclude that PAF antagonists like BN 52021 may be useful adjuncts for lung preservation. The effects of BN 52021 are easily explained by PAF antagonist activity in ischemic and reperfusion-induced pulmonary dysfunction. However this study does not exclude that BN 52021 may have direct effects.     

Endotoxin potentiates lung injury in cerulein-induced pancreatitis

BACKGROUND: In this study we examine the effect of endotoxin (lipopolysaccharide) on lung injury in the setting of acute pancreatitis (AP). METHODS: Twelve hourly injections of cerulein (50 microg/kg/h) were used to induce pancreatitis in mice. Intraperitoneal lipopolysaccharide (LPS [6 mg/kg]) was administered 24 hours after the initial cerulein injection. Twenty-four hours after LPS injection, myeloperoxidase (MPO) activity, nuclear factor (NF)-kappaB activation, and tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and chemokines MIP-2 and KC levels were measured in pancreas, liver, and lung tissues. Four groups of mice were studied: cerulein-LPS, cerulein-saline, saline-LPS, and saline-saline treated mice. RESULTS: Elevated serum lipase confirmed pancreatitis in cerulein treated mice. Lung MPO activity was significantly increased in the cerulein-LPS group. NF-kappaB was activated in the liver but not in pancreas and lung tissue. Chemokines MIP-2 and KC were elevated in pancreatic tissue only. CONCLUSIONS: These findings suggest that gram-negative infections may be an important predisposition for the development of adult respiratory distress syndrome in the setting of AP and that hepatic NF-kappaB may mediate multisystem injury.     

Role of platelet-activating factor in leukocyte-independent plasma extravasation and mast cell activation during endotoxemia

BACKGROUND: Independently from leukocyte adherence, endothelial factors and mast cell activation seems to promote microvascular permeability. Platelet-activating factor (PAF) has been shown to play a significant role in endotoxin-induced leukocyte adherence. The aim of our study was to investigate if there is also a role for PAF in mediating leukocyte-independent microvascular permeability changes and activation of mast cells during endotoxemia. Therefore, during endotoxemia microvascular permeability and mast cell activation were determined after inhibition of L-selectin-mediated leukocyte adherence by fucoidin and after inhibition of PAF effects by the PAF receptor antagonist BN52021. MATERIALS AND METHODS: In male Wistar rats, red cell velocity (V(RBC)), venular wall shear rate, microvascular permeability, leukocyte adherence, and mast cell activation were determined in mesenteric postcapillary venules using intravital microscopy at baseline and 60 and 120 min after start of a continuous infusion of endotoxin (ETX; 2 mg/kg/h, Escherichia coli O26:B6) (ETX group). Animals in the FUCO/ETX group received fucoidin (25 mg/kg body wt) in addition to the procedure described above. Animals in the FUCO/ETX/PAF-ANT group received fucoidin and the PAF receptor antagonist BN52021 (5 mg/kg body wt) prior to the continuous endotoxin infusion. Control animals (control group) received only equivalent volumes of NaCl 0.9%. RESULTS: There were no microhemodynamic and macrohemodynamic differences between groups. In all endotoxin-challenged groups macromolecular leakage and mast cell activity increased significantly, starting at 60 min. Both macromolecular leakage and mast cell activity were significantly higher in the FUCO/ETX group than in the FUCO/ETX/PAF-ANT group and control group. Differences in macromolecular leakage between groups were significant at 120 min. Differences in mast cell activity between groups were significant at 60 and 120 min. CONCLUSIONS: The results of our study demonstrate a leukocyte-independent plasma extravasation that can be inhibited by the PAF receptor antagonist BN52021, indicating the involvement of PAF in the pathophysiology of leukocyte-independent microvascular damage during early endotoxemia. Mast cell activity seems to precede leukocyte-independent macromolecular leakage.     

Protective effect of the PAF antagonist BN 52021 in an experimental renal warm ischemia model

Platelet activating factor is involved in warm ischemic damage. We studied the effect of the PAF receptor antagonist BN 52021 in an experimental model of 60 min of renal warm ischemia in which the left kidney was flushed with Euro-Collins solution and a right nephrectomy was performed. Eighty Wistar rats were divided into a sham-operated group, two control groups, and four study groups, according to the dosage and route of BN 52021 administration. BN 52021 was used in the flush solution at concentrations of 0.1 and 0.5 mg/ml, or intravenously prior to ischemia at 5 and 10 mg/kg body weight. Creatinine clearance per, 100g body weight, fractional sodium excretion, and conventional histology were studied. Rats that received BN 52021 intravenously showed a significantly higher creatinine clearance than controls. Intravenous BN 52021 produced a higher acceleration of renal function recovery at 10 mg/kg than at 5 mg/kg body weight. Conventional histology was better in animals that received BN 52021 at 10 mg/kg body weight than in controls. Addition of BN 52021 to Euro-Collins flushing solution showed no protective effect. We conclude that intravenous BN 52021 shows a renal protective effect against warm ischemia.     

Does somatostatin analogue prevent experimental acute pancreatitis?

Because somatostatin is a potent inhibitor of pancreatic secretion, we hypothesized that pretreatment with somatostatin analogue octreotide (SMS 201-995) might prevent cerulein-induced edematous pancreatitis. We studied 18 rats prepared with jugular vein catheters. The following agents were administered intravenously to groups of four rats for 6 hours: 1 mL/h (control) crystalloid solution; 1-microgram/kg bolus then 1 microgram/kg per hour of octreotide; and 5 micrograms/kg per hour of cerulein; also, in a fourth group of six rats, octreotide and cerulein were administered simultaneously. At the end of experiments, blood was drawn for plasma amylase determinations; rats were killed and pancreata were examined. Supramaximal cerulein administration to conscious rats induced hyperamylasemia and edematous pancreatitis, confirming previous observations; in both groups of rats receiving cerulein, there was prominent interstitial edema, acinar vacuolization, and mild-to-moderate acute inflammation. While octreotide pretreatment of rats with cerulein-induced acute pancreatitis was associated with a lesser increase of wet pancreas weight and plasma amylase concentration, there was little overall benefit of octreotide pretreatment in this form of experimental acute pancreatitis.     

Time course of bacterial infection of the pancreas and its relation to disease severity in a rodent model of acute necrotizing pancreatitis.

BACKGROUND: Bacterial infection of pancreatic necrosis is thought to be a major determinant of outcome in acute necrotizing pancreatitis. The determinants and possibilities for prophylaxis are unknown and difficult to study in humans. OBJECTIVE: The time course of bacterial infection of the pancreas in a rodent model of acute necrotizing pancreatitis was characterized. The authors ascertained if there is a correlation with the degree of necrosis. METHODS: Acute pancreatitis (AP) of graded severity was induced under sterile conditions by an intravenous infusion of cerulein (5 micrograms/kg/hr) for 6 hours (mild AP), or a combination of intravenous cerulein with an intraductal infusion of 10-mM glycodeoxycholic acid (0.2 mL for 2 min for moderate AP, 0.5 mL for 10 min for severe AP). Sham-operated animals (intravenous and intraductal NaCl 0.9%) served as controls. Ninety-six hours after induction, animals were killed for quantitative bacterial examination and histologic scoring of necrosis. In addition, groups of animals with severe AP were investigated at 12, 24, 48, 96, and 144 hours. RESULTS: No significant pancreatic necrosis was found in control animals (0.3 +/- 0.1) or animals with mild AP (0.6 +/- 0.1) killed at 96 hours. Necrosis scores were 1.1 +/- 0.2 for animals with moderate AP and 1.9 +/- 0.2 for animals with severe AP. Control animals did not develop significant bacterial infection of the pancreas (> or = 10(3) CFU/g). At 96 hours, the prevalence of infection was 37.5% in animals with mild AP and 50% in animals with moderate AP. In animals with severe AP, infection of the pancreas increased from 33% in the first 24 hours to 75% between 48 and 96 hours (p < 0.05). The bacterial counts and the number of different species increased with time and was maximal (> 10(11) CFU/g) at 96 hours. CONCLUSION: Bacterial infection of the pancreas in rodent AP increases during the first several days, and its likelihood correlates with the severity of the disease. This model, which closely mimics the features of human acute pancreatitis, provides a unique opportunity to study the pathogenesis of infected necrosis and test therapeutic strategies.     

Effect of somatostatin analogue and cholecystokinin receptor antagonist on bile-induced acute canine pancreatitis.

To determine whether a synthetic somatostatin analogue, octreotide, and a cholecystokinin receptor antagonist, L-364,718, may be beneficial in acute pancreatitis, 33 dogs were assigned to four groups. Each dog underwent laparotomy with injection of autologous bile into the dorsal pancreatic duct. Thirty minutes after the induction of pancreatitis, Group 1 received a subcutaneous injection of octreotide (200 micrograms/kg), Group 2 received an equal volume of the octreotide carrier, Group 3 received an hourly intravenous bolus of L-364,718 (60 micrograms/kg), and Group 4 received an equal volume of the L-364,718 carrier. Hemodynamic profiles, arterial blood gases, plasma glucose, and serum amylase were obtained before laparotomy, at bile injection, and at hourly intervals. The pancreas was removed after 8 hours for gross evaluation, measurement of water content, and histologic examination. A significant decrease in cardiac index and a significant increase in serum amylase and pancreatic edema occurred in all four groups 8 hours after the induction of pancreatitis (P less than 0.05), but there was no statistical difference between any group. Likewise, there was no difference in gross or histologic changes in the pancreas of any group. The somatostatin analogue, octreotide, and the cholecystokinin receptor antagonist, L-364,718, did not ameliorate the effects of severe, bile-induced pancreatitis in dogs.     

The effect of glucagon-like peptide 2 on intestinal permeability and bacterial translocation in acute necrotizing pancreatitis

BACKGROUND: Acute pancreatitis (AP) initiates a generalized inflammatory response that increases intestinal permeability and promotes bacterial translocation (BT). Impairment of the intestinal epithelial barrier is known to promote BT. Glucagon-like peptide 2 (GLP-2), a 33 residue peptide hormone, is a key regulator of the intestinal mucosa by stimulating epithelial growth. The purpose of this study was to determine whether GLP-2 decreases intestinal permeability and BT in AP. METHODS: To examine whether GLP-2 can decrease intestinal permeability and thereby decrease BT in acute necrotizing pancreatitis, 34 male Sprague-Dawley rats (200 to 300 g) were studied. AP was induced in group I and group II by pressure injection of 3% taurocholate and trypsin into the common biliopancreatic duct (1 mg/kg of body weight). The potent analog to GLP-2 called ALX-0600 was utilized. Group I rats received GLP-2 analog (0.1 mg/kg, SQ, BID) and group II rats received a similar volume of normal saline as a placebo postoperatively for 3 days. Group III and group IV received GLP-2 analog and placebo, respectively. At 72 hours postoperatively, blood was drawn for culture of gram-negative organisms. Specimens from mesenteric lymph nodes (MLN), pancreas and peritoneum were harvested for culture of gram-negative bacteria. Intestinal resistance as defined by Ohm's law was determined using a modified Ussing chamber to measure transepithelial current at a fixed voltage. A point scoring system for five histologic features that include intestinal edema, inflammatory cellular infiltration, fat necrosis, parenchymal necrosis, and hemorrhage was used to evaluate the severity of pancreatitis. Specimens from MLN, pancreas, jejunum, and ileum were taken for pathology. RESULTS: All group I and group II rats had AP. The average transepithelial resistance in group I was 82.8 Omega/cm(2) compared with 55.9 Omega/cm(2) in group II (P <0.01). Gram-negative BT to MLN, pancreas, and peritoneum was 80%, 0%, and 0%, respectively in group I compared with 100%, 30%, and 20% translocation in group II. CONCLUSION: GLP-2 treatment significantly decreases intestinal permeability in acute pancreatitis.     

银杏苦内酯B对重症急性胰腺炎胰腺组织病理变化的影响

目的 通过银杏苦内酯B(BN52021)对血小板活化因子(PAF)的拮抗作用,探讨BN52021治疗重症急性胰腺炎(SAP)的疗效.方法 Wistar大鼠180只按随机数字表法分为对照组(60只)、SAP组(60只)、BN52021组(60只),每组按不同时相点(1、2、3、6、12、24 h)分为6小组,分别监测血清淀粉酶的变化,用RT-PCR和Western blot法分别监测胰腺组织PAF受体mRNA和蛋白表达的变化,同时对胰腺组织进行病理学观察.多组比较采用单因素方差分析.结果 血清淀粉酶和病理学结果显示SAP制模成功,BN52021组血清淀粉酶在3、6、24 h[(4185 ±148)U/L,(3785 ±124)U/L,(1360 ±161)U/L]较SAP组[(4799 ±107)U/L,(4920±140)U/L,(2283±127)U/L]显著降低,病理学评分在3、6、12 h(5.95 ±0.19,5.55 ±0.36,6.72 ±0.30)较SAP组(8.85±0.39,9.15±0.55,10.10±0.65)显著降低;PAF受体mRNA及蛋白检测结果显示,SAP组和BN52021组早期逐渐上升(0.49±0.09～0.71±0.14,0.43±0.06～1.69±0.06),在3 h达到高峰,3组比较差异有统计学意义(F=4.58.6.24,P<0.05).结论 PAF受体在SAP大鼠胰腺组织中表达是动态变化的,PAF受体参与了SAP病情的发生、发展;BN52021可降低SAP血清淀粉酶和改善胰腺组织病理变化,发挥了一定的治疗作用,但对胰腺组织PAF受体的表达无显著影响.     

Platelet activating factor antagonism reduces the systemic inflammatory response in a murine model of acute pancreatitis

BACKGROUND: The platelet activating factor (PAF) antagonist, Lexipafant, has been used in experimental models and clinical trials to treat severe acute pancreatitis (AP). The purpose of this study was to determine whether Lexipafant reduces the local and systemic components of AP in a murine model of mild, edematous AP. MATERIALS AND METHODS: Forty-eight female Swiss-Webster mice were divided into four groups. Group 1 received 50 microl of saline ip every hour for 6 h (sham). Group 2 received saline treatment, plus Lexipafant (25 mg/kg dose ip, every 3 h starting 1 h after the first saline injection) (sham/Lex). Group 3 received cerulein (50 microg/kg dose ip, every hour for 6 h) (AP). Group 4 received AP, plus therapeutic treatment with Lexipafant (AP/Lex). Animals were sacrificed 3 h after the last injection. Serum cytokine levels were determined by ELISA. Standard assays were performed for serum amylase activity and lung myeloperoxidase activity (MPO). Histology was scored by two blinded investigators. RESULTS: Serum cytokines (TNFalpha, IL-1beta), lung MPO, and serum amylase activity were reduced by PAF antagonism. Histology showed a trend toward improvement with Lexipafant, but did not reach statistical significance. CONCLUSION: The PAF antagonism reduces the severity of systemic inflammation when given after the induction of mild AP in mice. These results suggest that Lexipafant may be useful in the treatment of mild pancreatitis after its clinical onset.     

Prevention of cyclosporin nephrotoxicity with a platelet-activating factor (PAF) antagonist

BACKGROUND.: Cyclosporin (CsA) is a potent immunosuppressive drug whose mainside-effect is nephrotoxicity. In the kidney, CsA induces vasoconstrictionwith a decrease in renal blood flow (RBF) and glomerular filtrationrate (GFR) and a significant increase in renal vascular resistance(RVR). CsA enhances platelet-activating factor (PAF) synthesisin mesangial cells in vitro. PAF, a secondary mediator of anaphylaxisand inflammation, exhibits vasoactive properties in the kidneysimilar to those of CsA. METHODS.: The in situ autoperfused rat kidney model was used to investigatewhether PAF plays a role in the haemodynamic injury inducedby CsA. RESULTS.: In this model, CsA (40 mg/kg and 20 mg/kg i.v.) induced a significantdecrease in RBF and in GFR and an increase in RVR. BN 52021,a potent and specific PAF antagonist (20 mg/kg i.v. bolus dose)induced a significant increase in GFR (137±32% of initialvalue, P<0.05). BN 52021 (20 and 10 mg/kg) also significantlyprevented the decline in RBF and GFR induced by CsA. CONCLUSIONS.: We have demonstrated that the PAF antagonist BN 52021 can minimizethe alteration of renal function induced by CsA.     

Effects of heparin in experimental models of acute pancreatitis and post-ERCP pancreatitis

BACKGROUND: Acute pancreatitis (AP) is a complication of diagnostic or therapeutic endoscopic retrograde cholangiopancreatography (ERCP). In a recent clinical trial, a decreased rate of post-ERCP pancreatitis was shown after prophylactic heparin treatment. The aim of this study was to evaluate the effects of prophylactic heparin application in various experimental models of AP and pancreatic duct obstruction and to assess the underlying mechanisms. METHODS: In various experimental models, pancreatic injury of graded severity was induced in Wistar rats: (1) mild pancreatitis by IV cerulein infusion over 6 hours; (2) severe pancreatitis by infusion of glycodeoxycholic acid into the pancreatic duct plus IV cerulein application over 6 hours. The clinical ERCP situation was imitated in groups (3) obstruction of the pancreatic duct and (4) infusion of contrast medium into the pancreatic duct plus obstruction. In every group the animals received either no heparin (n=six per group) or continuous IV heparin (n=six per group) starting before pancreatic injury. Histologic changes, amylase, and lipase in plasma were evaluated 12 hours after induction of pancreatic injury. Additional animals were treated to investigate pancreatic microcirculation by intravital microscopy (n=six per group). RESULTS: In groups 1, 3, and 4 (mild AP/duct obstruction/duct obstruction plus contrast medium), IV heparin-treated animals showed reduced edema, inflammation, and peak amylase values compared with the corresponding non-heparin-treated animals (P<.05). Moreover, mean erythrocyte velocity was significantly higher and leukocyte-endothelium interaction was reduced in these groups after prophylactic administration of heparin. In contrast, group 2 (severe AP) did not show any difference between control animals and animals that received heparin as assessed by histology and intravital microscopy. CONCLUSIONS: Prophylactic systemic application of heparin provides a protective effect in mild AP and in experimental post-ERCP pancreatitis. The mechanism of the protective effects of heparin seems to be the reduction of leukocyte-endothelium interaction and the normalization of pancreatic microcirculation.     

Decreased inflammation and improved survival with recombinant human activated protein C treatment in experimental acute pancreatitis

HYPOTHESIS: Drotrecogin alfa (activated), the pharmacologic form of activated protein C and the first Food and Drug Administration-approved drug for treatment of severe sepsis, is beneficial in experimental acute pancreatitis (AP). DESIGN: Animal study. SETTING: Laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Mild (intravenous cerulein) or severe (intravenous cerulein plus intraductal glycodeoxycholic acid) AP was induced in 72 rats, and coagulation evaluated. Rats with severe AP were randomized to treatment with drotrecogin alfa (activated), 100 microg/kg per hour, or isotonic sodium chloride. MAIN OUTCOME MEASURES: Histologic scoring of pancreatic necrosis, inflammation of the pancreas and lung (measured by myeloperoxidase concentration), coagulation measures, and 24-hour survival. RESULTS: Severe consumptive coagulopathy, hemoconcentration, and leukocytosis were observed 6 hours after induction of severe AP, but not in mild AP. Treatment of AP with drotrecogin did not worsen coagulation measures. Although the degree of pancreatic necrosis was comparable in treated and untreated animals with severe AP, drotrecogin significantly reduced myeloperoxidase levels in the pancreas (P = .009) and lungs (P = .03). The 24-hour survival in severe AP was markedly improved in animals treated with drotrecogin (86% vs 38%; P = .05). CONCLUSIONS: Animals with severe AP have severe consumptive coagulopathy, but administration of drotrecogin alfa (activated), 100 microg/kg per hour, does not worsen coagulation abnormalities. Drotrecogin treatment reduces inflammation in the pancreas and lungs and significantly improves survival. These results encourage clinical investigation of drotrecogin in the treatment of severe AP.     

Impact of PAF antagonist BN 52021 (Ginkolide B) on post-ischemic graft function in clinical lung transplantation.

BACKGROUND: Platelet activating factor (PAF) is associated with ischemia/reperfusion injury (I/R) after lung transplantation. Following promising experimental results, this prospective trial investigated the potential effect of PAF antagonist BN 52021 (ginkolide B) on clinical Euro-Collins (EC)-based lung preservation. METHODS: We analyzed 8 double-lung transplant patients in each of 3 groups. In the low-dose group (LDG), donor lungs were perfused with EC containing 2 mg/kg BN 52021, whereas we used 10 mg/kg in the high-dose group (HDG) and placebo in the control group (CG). Before reperfusing the first lung, we administered intravenously 120 mg BN 52021 (LDG), 600 mg BN 52021 (HDG), or placebo (CG). Hemodynamics in terms of pulmonary arterial pressure, pulmonary vascular resistance and serial determinations of the alveolo-arterial oxygen difference (AaDO(2)) were recorded. We measured blood levels of PAF pre-operatively and post-operatively, after 10 minutes and after 3, 8, 24, 48, and 144 hours. RESULTS: Within 32 hours, we noted a tendency toward better AaDO(2) in the LDG and the HDG compared with the CG (p > 0.05). We observed a significant improvement of AaDO(2) after 3 hours (HDG, p = 0.033) and 8 hours (LDG, p = 0.024), with poorest values in the CG. The PAF concentrations were lowest in the HDG, with significant deterioration 10 minutes after reperfusion. In contrast, placebo led to higher PAF levels. We measured significantly lower PAF concentrations (HDG vs CG) at 10 minutes and at 6 days post-operatively. CONCLUSIONS: Use of high-dose PAF antagonist BN 52021 can easily be combined with clinical preservation methods and may help optimize pulmonary function with reduced PAF levels, in the early post-ischemic period.     

Enzymatic and histological alterations in the isolated perfused rat pancreas in the taurocholate and cerulein model of acute pancreatitis]

METHODS: The pancreas of 24 male Wistar rats was perfused extracoporally by modified Krebs-Ringer-buffer for 80 minutes (including a 20 minutes equilibration period). To verify any organ damage we measured the activity of pancreatic enzymes like amylase, lipase and lactatdehydrogenase in the portal effluent. Furthermore histological changes were analysed after perfusion. Organ damage was induced by adding cerulein in a physiological dose (10(-10) M, n = 6) and in a supramaximal dose (10(-8) M, n = 6) and by intraductal injection of taurocholate (3.5 %, n = 6). RESULTS: Already 10 minutes after stimulation with cerulein (10(-8) M) and after intraductal injection of taurocholate increased activities (p < 0.01) of amylase and lipase were measured in the portal effluent compared to the group without any treatment. Lactatdehydrogenase levels did not changed. Apart from marked oedema in both groups considerable zones of necrosis could be noticed especially in the taurocholate group. CONCLUSION: Our data suggest that the isolated perfused rat pancreas (IPRP) is a valuable experimental tool to verify pathophysiological changes in the early phase of acute pancreatitis (AP). Various established models of AP such as by cerulein hyperstimulation or intraductal injection of taurocholate, could be applied to the IPRP. We conclude that this method enlarges the spectrum of established experimental models of acute pancreatitis.     

不同剂量坎地沙坦治疗大鼠急性胰腺炎的实验研究

目的：探讨选择性血管紧张素Ⅱ受体亚型AT1拮抗剂坎地沙坦不同剂量对大鼠急性胰腺炎（AP）的影响。方法：72只雄性SD大鼠随机分为正常对照组、AP组、AP＋低剂量坎地沙坦组（2 mg/kg）、AP＋高剂量坎地沙坦组（10 mg/kg）。腹腔注射20%L-精氨酸溶液建立AP动物模型;坎地沙坦用大鼠灌胃针灌注。各组大鼠分别在造模后12 h、24 h、48 h分批次等数量（6只/组/批）心脏取血处死。取胰腺组织观察胰腺病理变化并评分（按Rongione标准）,胰腺/体质量比,检测大鼠血清脂肪酶、TNF-α、IL-10的变化。结果：AP组胰腺炎症评分,胰腺/体质量比,血清脂肪酶、TNF-αI、L-10较对照组明显升高（P〈0.01）。其中胰腺/体质量比于造模后12 h已有明显升高,于48 h达到高峰;而血清脂肪酶和胰腺TNF-αI、L-10于造模后12 h达到高峰,此后有所下降,但仍然保持较高水平。坎地沙坦干预的实验组胰腺炎症评分,胰腺/体质量比,血清脂肪酶、TNF-α以及胰腺TNF-α较AP组降低（P〈0.05）,但低剂量坎地沙坦组与高剂量组间无显著差异（P〉0.05）。本实验中,应用坎地沙坦对AP大鼠血清及胰腺IL-10均无显著影响（P〉0.05）。结论：应用AT1受体拮抗剂坎地沙坦可以明显减轻L-精氨酸诱导大鼠急性胰腺炎的炎症及损伤。     

Peptide YY exhibits a mitogenic effect on pancreatic cells while improving acute pancreatitis in vitro

BACKGROUND: Peptide YY (PYY), a gastrointestinal regulatory peptide, improves survival and histologic parameters in animal models of acute pancreatitis. Its effects on pancreatic cell growth and acute pancreatitis in pancreatic acinar and ductal cells are unknown. We hypothesized that PYY would affect cell growth and attenuate acute pancreatitis in pancreatic acinar and ductal cells in vitro. METHODS: Rat pancreatic acinar and ductal cells were cultured in the presence of 1) cerulein, a synthetic cholecystokinin analog that induces pancreatitis, 2) PYY, or 3) a combination group pretreated with PYY prior to addition of cerulein. Cell survival was measured at 48 h using MTT assay. Amylase secretion, as marker for pancreatitis, was measured at 48 h using an amylase activity assay. Statistical significance was calculated using analysis of variance and the Student's t test. RESULTS: Peptide yy significantly increased cell growth and decreased amylase secretion compared with control and cerulein groups. Pretreatment with PYY significantly protected against the pancreatitis effects of cerulein. CONCLUSIONS: We have shown for the first time that PYY has a mitogenic effect on pancreatic acinar and ductal cells in vitro. In addition, it directly protects against cerulein-induced pancreatitis. Its potential therapeutic benefit in acute pancreatitis would therefore be twofold: amelioration of the inflammatory process, and augmenting growth of normal pancreas to replace necrotic or apoptotic cell loss.