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Background & Aims: The mechanism by which alcohol injures the pancreas remains unknown. Alcohol-intoxicated humans have high levels of fatty acid ethyl esters (FAEEs), nonoxidative products of ethanol metabolism, in blood, pancreas, and liver. The aims of this study were to determine whether FAEEs are toxic to the pancreas in vivo and, if so, to assess whether this injury is specific to the pancreas and to compare it to the injury observed in acute pancreatitis., Methods: FAEEs were infused into Sprague-Dawley rats. Levels of FAEEs in plasma and pancreas were measured, and pancreatic injury was assessed during a 48-hour period for edema formation and ectopic trypsinogen activation and by light and electron microscopy., Results: FAEEs induced highly significant increases in pancreatic edema, pancreatic trypsinogen activation, and vacuolization of acinar cells. These findings were specific to the pancreas and were not found in liver, lung, myocardium, skeletal muscle, or subcutaneous fat., Conclusions: FAEEs at concentrations found in human plasma produce a pancreatitis-like injury in rats, providing direct evidence that FAEEs can produce organ-specific toxicity. Thus, FAEEs may contribute to acute alcohol-induced damage to the pancreas.

Objective: The potential of pancreatic ischemia to cause acute pancreatitis as indicated by morphologic changes and ectopic trypsinogen activation was investigated., Background: Experimental evidence has shown that pancreatic ischemia is important in the evolution of severe pancreatitis, but whether ischemia can initiate pancreatitis has been disputed., Methods: Pancreatic ischemia was induced in rats by hemorrhagic hypotension (30 mm Hg for 30 min; n = 64). Changes of pancreatic microcirculatory perfusion were studied using diffuse reflectance spectroscopy. Serum amylase, trypsinogen activation peptide (TAP) in serum and pancreatic tissue, wet/dry weight ratio, and histology were determined over 24 hours and compared with sham-operated control subjects (n = 35)., Results: In control animals, serum amylase (47.9 +/- 2.1 units/L), serum (7.9 +/- 0.7 nmol/L) and tissue TAP (63.0 +/- 5.4 nmol/L x g), wet/dry weight ratio (2.8 +/- 0.1), and histology remained unchanged. Temporary hypotension markedly decreased pancreatic perfusion with incomplete recovery after reperfusion. Pancreatic isoamylase activity increased within 1 hour (110 +/- 5 units/L, p < 0.05) and further to 151 +/- 18 units/L at 24 hours. Tissue TAP was elevated at 1 hour (134 +/- 16 nmol/L x g, p < 0.05) and increased to 341 +/- 43 nmol/L x g (p < 0.001) after 24 hours, whereas serum TAP remained unchanged (8.3 +/- 0.5 nmol/L). Morphologic alterations included elevated wet/dry weight ratio (4.1 +/- 0.3, p < 0.01) and increased histologic scores for edema (p < 0.05) and acinar necrosis (p < 0.05) at 24 hours. Trypsinogen activation preceded the development of pancreatic necrosis., Conclusions: In addition to its potentiating role, severe pancreatic ischemia can play a pathogenetic role in the initiation of acute pancreatitis.

Objective: To evaluate the factors thought to be involved in the pathogenesis of acute pancreatitis associated with alcohol., Background: The mechanism of alcohol-induced pancreatitis is believed to involve synergistic effects of various pathogenetic factors. The present study was designed to evaluate the possible contribution of pancreatic duct obstruction, physiologic exocrine stimulation, or secretory hyperstimulation to alcohol-induced pancreatic injury., Methods: Wistar rats were allocated randomly to a control group (group 1), or to a group with pancreatic duct obstruction (group 2), physiologic exocrine stimulation (group 3), ductal obstruction and exocrine stimulation (group 4), or exocrine hyperstimulation with the cholecystokinin analogue cerulein (group 5). Three hours after this pretreatment, animals in each experimental group were randomly divided into two subgroups for intragastric administration of either water (groups 1A through 5A) or beer (groups 1B through 5B). Test solutions were instilled over 9 hours (total amount of alcohol administered, 4.8 g/kg). Twenty-four hours after beginning the test infusion, animals were killed for histologic evaluation of pancreatic edema and determination of an acinar cell necrosis score. Serum amylase levels were determined at 3, 9, and 24 hours., Results: No increase in amylase levels or significant morphologic changes were found in control animals (group 1A) or in animals subjected to physiologic exocrine stimulation (group 2A). Pancreatic duct obstruction, with or without physiologic exocrine hyperstimulation (groups 3A and 4A), and exocrine hyperstimulation (group 5A) induced pancreatitis of similar severity with minor acinar cell damage. Alcohol superimposed on exocrine hyperstimulation (group 5B) increased acinar cell injury (group 5A, 0.4 +/- 0.1 points vs 5B, 1.0 +/- 0.2 points; P < .05) and serum amylase levels at 24 hours (group 5a, 41 +/- 6 U/L vs group 5B, 72 +/- 11 U/L; P < .05), whereas no differences between subgroups A and B (water vs beer) were found in groups 1 through 4., Conclusion: Our findings suggest that the pathogenesis of acute alcoholic pancreatitis may require a state of exocrine hyperstimulation, perhaps via cholecystokinin, but do not support a role for constriction or obstruction of Oddi's sphincter.

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.