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.

[Antioxidative effect of N2-mercaptopropionylglycine (N2 MPG) in experimental acute pancreatitis]. / Efeito do antioxidante N2-mercaptopropionilglicina (N2-MPG) na pancreatite aguda experimental.

The N2-Mercaptopropionylglycine (N2-MPG) is a potent antioxidant by inhibiting the abnormal production of xantina-oxidase. The aim of this research is to analyze the antioxidant capacity of this tiol compound by offering some protection to pancreatic tissue in the acute pancreatitis (AP). The induction of AP was obtained through two methods: a) supramaximal dose of cerulein; b) infusion of 2.5% sodium taurocholate into the biliopancreatic duct of the rat. Thirty-six male Wistar rats (220-270 g) were divided into four groups. AP with cerulein (Two parenteral doses of 20 micrograms/kg; one hour interval): in two groups: GI: nineteen rats previously treated with N2-MPG (100 mg/kg) ten minutes before AP. GII (control): seventeen animals which received saline 0.9%. AP with taurocholate (0.5 ml into the main biliopancreatic duct): in other two groups: GIII: eleven rats previously treated with N2-MPG (100 mg/kg) ten minutes before AP. GIV (control): fifteen animals which received saline 0.9%. The albumin leakage into the cell interstice as an inflammatory parameter was measured through Evans-Blue (EB) colorimetry, that links totally with serum albumin after injection into the pancreatic tissue, immediately before induction of AP. The rats were sacrificed one hour after. Water tissue content was also measured. There was a relevant reduction of EB leakage in GI (344 +/- 27 micrograms/gtissue) when compared to GII (729 +/- 84 micrograms/gtissue), p < 0.01, and in GIII (386 +/- 52 micrograms/gtissue) when compared to GIV (543 +/- 53 micrograms/gtissue), p < 0.05. There was no difference in tissue water content between GI (88.2 +/- 0.6%) and GII (87.4 +/- 0.9%), but certainly between GIII (77.7 +/- 2.1%) and GIV (82.8 +/- 1.2%), p < 0.05. The amilase levels didn't show any difference among the four groups. These results suggest that the use of the antioxidant N2-MPG offers a protective action, at least in rats, reducing the severity of AP induced by supramaximal dose of cerulein, and even in a more severe AP such as produced by sodium taurocholate at 2.5%, although apparently not interfering with its pathogenesis. It also strengthens the actual participation of free radicals of oxygen in the physiopathology of acute pancreatitis.

[Hepatic lesion in experimental acute pancreatitis. Influence of pancreatic enzyme storage reduction]. / Lesão hepática na pancreatite aguda experimental. Influência da redução da reserva enzimatica do pâncreas.

Acute Pancreatitis (AP) is known to produce morphologic and functional changes in liver. Administration of low doses of caerulein significant decreases the content of pancreatic enzymes, leading to reduced mortality of animals submitted to AP. The present study was designed to assess the effect of acute reduction of pancreatic enzymatic content in the hepatic mitochondrial function. Wistar male rats, submitted to AP by injection of Na thaurocholate into the pancreatic duct, with and without previous i.v. injection of 0.133 microgram Kg-1h-1 of caerulein for three hours, were divided in four groups: Group I: No caerulein infusion and AP; Group II: Previous caerulein infusion and with AP; Group III: Caerulein infusion without AP; Group IV (control): No caerulein infusion and without AP. After 2 hours of induction of AP the livers were removed and prepared to the mitochondrial oxidative and phosphorylative activities, measured polarographically with determination of oxygen consumption without ADP (Basal respiration-State 4) and in the presence of ADP (Activated respiration-State 3). Ascitic fluid contents of amylase, trypsin and total protein were routinely determined. After 2 hours of AP there was a significant increase in state 4 respiration (41%) and a decrease in respiratory control ratio and in ADP/O ratio (p < 0.05) in animals of Group I (AP without caerulein) when compared to Group II (AP with caerulein) (Table 1). Ascitic fluids contents of amylase (A) and trypsin (T) showed decrease in animals of Group II with AP that received previous caerulein infusion (A = 80 +/- 10 U/ml, T = 9.75 +/- 1.25 U/ml), when compared to animals of Group I that did not receive caerulein (A = 231 +/- 24, T = 40.32 +/- 5.19) (p < 0.001). Caerulein infusion by itself (Group III) did not have any influence on mitochondrial liver dysfunction. Reduction of pancreatic enzyme content through caerulein infusion attenuates the damage of mitochondrial respiration, demonstrated by uncoupling phase on mitochondrial function in experimental AP. Further studies are needed to elucidate this phenomena, but it is probably related to the decreased of the pathogenic effects of pancreatic activated enzymes that reach the systemic circulation in reduced amounts.

Hepatic damage during acute pancreatitis in the rat.

We studied the alterations in the metabolism of liver mitochondria in rats with acute pancreatitis. Male Wistar rats were allocated to a control group (group I) and to five other groups corresponding to 2, 4, 12, 24 and 48 h after the induction of acute pancreatitis by the injection of 5% sodium taurocholate into the pancreatic duct. Sham-operated animals were submitted to the same surgical steps except for the induction of acute pancreatitis. Mitochondrial oxidation and phosphorylation were measured polarographically by determining oxygen consumption without ADP (basal respiration, state 4) and in the presence of ADP (activated respiration, state 3). Serum amylase, transaminases (ALT and AST) and protein were also determined. Ascitic fluid, contents of amylase, trypsin and total protein were also determined and arterial blood pressure was measured in all groups. In ascitic fluid, trypsin and amylase increased reaching a maximum at 2 and 4 h, respectively. Serum amylase increased at 2 h reaching a maximum at 4 h. Serum transaminase levels increased at 12 and 24 h. After 2 h (and also 4 h) there was an increase in state 4 respiration (45.65 +/- 1.79 vs 28.96 +/- 1.50) and a decrease in respiration control rate (3.53 +/- 0.09 vs 4.45 +/- 0.08) and in the ADP/O ratio (1.77 +/- 0.02 vs 1.91 +/- 0.01) compared to controls (P < 0.05). These results indicate a disruption of mitochondrial function, which recovered after 12 h. In the 48-h groups there was mitochondrial damage similar to that occurring in ischemic lesion. Beat-to-beat analysis (30 min) showed that arterial blood pressure remained normal up to 24 h (111 +/- 3 mmHg) while a significant decrease occurred in the 48-h group (91 +/- 4 mmHg). These data suggest biphasic damage in mitochondrial function in acute pancreatitis: an initial uncoupled phase, possibly secondary to enzyme activity, followed by a temporary recovery and then a late and final dysfunction, associated with arterial hypotension, possibly related to ischemic damage.

Hepatic damage during acute pancreatitis in the rat

We studied the alterations in the metabolism of liver mitochondria in rats with acute pancreatitis. Male Wistar rats were allocated to a control group (group I) and to five other groups corresponding to 2,4, 12,24 and 48 h after the induction of acute pancreatitis by the injection of 5 per cent sodium taurocholate into the pancreatic duct. Sham-operated animals were submitted to the same surgical steps except for the induction of acute pancreatitis. Mitochondrial oxidation and phosphorylation were measured polarographically by determining oxygen consumption without ADP (basal respiration, state 4) and in the presence of ADP (activated respiration, state 3). Serum amylase, transaminases (ALT and AST) and protein were also determined. Ascitic fluid, contents of amylase, trypsin and total protein were also determined and arterial blood pressure was measured in all groups. In ascitic fluid, trypsin and amylase increased reaching a maximum at 2 and 4h, respectively. Serum amylase increased at 2 h reaching a maximum at 4 h. Serum transaminase levels increased at 12 and 24 h. After 2 h (and also 4 h) there was an increase in state 4 respiration (45.65 + 1.79 vs 28.96 + 1.50) and a decrease in respiration control rate (3.53 + 0.09 vs 4.45 + 0.08) and in the ADP/O ratio (1.77 + 0.02 vs 1.91 + 0.01) compared to controls (P<0.05). These results indicate a disruption of mitochondrial function, which recovered after 12 h. In the 48-h groups there was mitochondrial damage similar to that occurring in ischemic lesion. Beat-to-beat analysis (30 min) showed that arterial blood pressure remained normal up to 24 h (111 + 3 mmHg) while a significant decrease occurred in the 48-h group (91 + 4 mmHg). These data suggest biphasic damage in mitochondrial function in acute pancreatitis: an inital uncoupled phase, possibly secondary to enzyme activity, followed by a temporary recovery and then a late and final dysfunction, associated with arterial hypotension, possibly related to ischemic damage.

[Physiopathology of lung injury in acute pancreatitis]. / Fisiopatologia da lesão pulmonar na pancreatite aguda.

Clinically detectable signs of lung injury develop in up to 50-70 percent of patients with acute pancreatitis. Despite that, the physiopathology of the lung injury associated with acute pancreatitis is unclear so far. Pulmonary edema is the main respiratory complication in acute pancreatitis. Increased permeabilities of the pulmonary endothelial and alveolar epithelial barriers are the causes of the pulmonary edema. Several factors have been regarded as the cause to pulmonary edema: release of pancreatic-derived proteolytic enzymes, oxygen-free radicals, phospholipase A2, free fat acids, tumor necrosis factor, platelet activating factor, arachidonic acid metabolites and pulmonary embolization. Understanding lung injury physiopathology enables physicians to a better therapeutic approach of the patients with acute pancreatitis. The aim of this paper is to expose the theories that explain the pancreatic-derived lung injury.

[Bacterial translocation in acute pancreatitis. Experimental study in rats]. / Translocação bacteriana na pancreatite aguda. Estudo experimental em ratos.

Ninety Wistar rats were studied to confirm if the intestinal tract is a source of infection in acute pancreatitis. Bacterial translocation to the mesenteric lymph nodes, pancreas, peritoneal cavity, and blood was determined at 6 h, 24 h, 48 h and 96 hours after induction of non lethal acute pancreatitis. Bacterial growing was present in 60% (6 h), 90% (24 h), 70% (48 h) and 40% (96 h) (p < 0.05) of the mesenteric lymph nodes. Live bacteria were recovered from 67% (6 h), 90% (24 h), 50% (48 h) and 40% (96 h) (p < 0.05) of the pancreas. Gram-positive bacteria translocate more frequently than Gram-negative bacteria in the early period (6 h). Lately (24-96 h), Gram-negative bacteria were much more frequently isolated (p < 0.05). The most common organism isolated was Escherichia coli. No overgrowth of cecal Gram-negative bacteria was found. It is concluded that bacterial translocation in acute pancreatitis is an early phenomena, initially caused by Gram-positive bacteria and lately by Gram-negative bacteria, and associated with the severity of pancreatic lesions.

[Protective effect of reduction of pancreatic enzyme content on the pulmonary disease induced by acute pancreatitis]. / Efeito protetor da redução do conteúdo enzimático do pâncreas na lesão pulmonar da pancreatite aguda.

Lung injury develop in up to 50-70 percent of patients with acute pancreatitis. Cerulein in physiological doses reduces the rate mortality of pancreatitis by decreasing the enzyme content of the pancreas. In order to assess the effect of acute reduction of pancreatic enzyme content on the pancreatitis pulmonary injury, pancreatitis was induced in Wistar rats by intraductal injection of 5 per cent sodium taurocholate: group I, with pancreatitis; group II, pancreatitis after decreasing pancreatic enzyme content; group III, control group. Dye Evans blue was used to evaluate the lung injury. The pancreatitis pulmonary injury was smaller in group II than group I (P < 0.05) but it was similar to control group (group III). In conclusion, it is speculated that the reduction of the pancreatic enzyme content reduces the pancreatitis pulmonary injury by decreasing the quantity of pancreatic enzymes reaching the systemic circulation.

[Lung injury in acute pancreatitis. Influence of pancreatic enzymes reduction]. / Lesão pulmonar na pancreatite aguda. Influência da redução do conteúdo enzimático do pâncreas.

UNLABELLED: A previous report has show that cerulein in physiological doses reduces the rate mortality of pancreatitis by decreasing the enzyme content of the pancreas. Clinically detectable signs of lung injury develop in up to 50-70 percent of patients with acute pancreatitis. The aim of the present study was to assess the effect of acute reduction of pancreatic enzyme content on the pancreatitis pulmonary injury. Experimental haemorrhagic pancreatitis was induced by intraductal injection of 5 per cent sodium taurocholate in two groups of Wistar rats: group I (pancreatitis) and group II (pancreatitis after decreasing pancreatic enzyme content). Dye Evans blue was used to evaluate the lung injury. The degree of histologically observed lesions were similar in both groups, but the pulmonary lesion was smaller in group II than group I (p < 0.05). IN CONCLUSION: 1) pancreatitis' pulmonary lesion may be related with pancreatic enzymes that reach the blood stream and 2) the reduction of the pancreatic enzyme content has a beneficial effect on acute pancreatitis and reduces its pulmonary injury.

[Lung lesion in acute pancreatitis]. / Lesão pulmonar na pancreatite aguda.

Clinically detectable signs of lung injury develop in up to 70 percent of patients with acute pancreatitis. In order to study the pulmonary injury, experimental haemorrhagic pancreatitis was induced in 63 Wistar rats by intraductal injection of 5 per cent sodium taurocholate. Investigations were carried out 2, 4, 6, 12, 24 and 48 hours after the end of pancreatitis induction. Lung injury was maximal at 12 hours after pancreatitis induction, pancreatic enzymes (amylase and trypsin) in peritonial fluid were maximal early (2-4h) and serum levels were maximal at about 4 hours after induction. In conclusion, in experimental acute pancreatitis pulmonary injury occurs 12 h after the start of infusion with increase in vascular permeability of the lung. This lesion may be related to pancreatic enzymes in peritonial fluid and blood.

Effect of PAF antagonists on cerulein-induced pancreatitis.

The present study was undertaken to investigate the involvement of PAF in acute pancreatitis induced by cerulein in rats. Cerulein (two doses of 20 micrograms/rat, the first s.c. and the second i.v., 1 h apart) induced a significant increase in vascular permeability in the pancreas, evaluated by the Evans blue (EB) extravasation method. Plasma amylase levels were also significantly increased in this group. The PAF antagonists, BN-52021 (5 mg/kg) and WEB-2170 (1 and 10 mg/kg), both significantly reduced the extravasation of EB in the pancrease induced by i.v. injection of PAF (1 microgram/kg). At these concentrations, BN-52021 was effective at inhibiting cerulein-induced pancreatitis (60-70% of inhibition) whereas WEB-2170 had no significant effect. Although the inhibition induced by BN-52021 suggests the involvement of PAF in cerulein-pancreatitis, the lack of effect of WEB-2170 reported here does not allow a definite conclusion. Further studies are needed to elucidate the differential effect of the PAF antagonists.

[Simplified model of induction of experimental acute pancreatitis with a supra-maximal dose of cerulein]. / Modelo simplificado de indução de pancreatite aguda experimental com uso de dose supramáxima de ceruleína.

The study was performed to compare an usual method of induction of acute experimental pancreatitis with a simplified, easier and faster induction through a subcutaneous and intravenous injection of cerulein, with good reproducibility as compared to the literature. Four groups were studied. In the group I, continuous three hour intravenous injection of 15 micrograms/Kg of cerulein, was given. Group II was a control group with saline infusion. Group III received a subcutaneous injection of 20 micrograms/Kg and an intravenous injection of 20 micrograms/Kg of cerulein one hour later. Group IV was the control group with saline. The results of biochemical measurements, such as tecidual trypsinogen, chimotrypsinogen, proelastase, cathepsin and serum amylase, showed no difference between the two methods. Histologic study revealed edematous pancreatitis in group I and III, with moderate acinar necrose in group III. These results suggest that the proposed simplified method induces enough acute and edematous pancreatitis to allow studies in physiopathology and therapeutics.