Katsuhiro Imanishi

Changes of Xanthine Oxidase, Lipid Peroxide and Superoxide Dismutase in Mouse Acute Pancreatitis

The role of free radicals in the development of pancreatitis was evaluated by measuring the level of activities of xanthine oxidase (XOD), lipid peroxide (LPO) and superoxide dismutase (SOD). Acute pancreatitis was induced in female mice fed a choline-deficient meal containing 0.5% DL-ethionine (CDE meal). Acute pancreatitis was confirmed by the changes in serum amylase level and other typical features observed microscopically 24 h after the meal was taken. Activity of XOD was elevated significantly (p less than 0.05) from the baseline of 1.13 +/- 0.19 U/g tissue to 2.34 +/- 0.46, 2.59 +/- 0.33 and 3.46 +/- 0.70 U/g tissue, 8, 12 and 24 h, respectively, after the CDE meal. The LPO level was also increased from an undetectable amount to 1.10 +/- 0.47 nmol/ml (p less than 0.05), 1.03 +/- 0.18 (p less than 0.01) at 6 and 8 h, respectively, and then returned to an undetectable amount at 12 h. The peak level of LPO was shown at 24 h, 1.76 +/- 0.40 nmol/ml (p less than 0.01) and gradually decreased until 48 h, 1.17 +/- 0.37 nmol/ml (p less than 0.01) after the CDE meal. Changes of LPO took a biphasic pattern. SOD was decreased significantly from 47.1 +/- 3.4 mU/g tissue to 30.7 +/- 2.5, 24.8 +/- 1.7 and 20.6 +/- 1.1 mU/g tissue at 8 (p less than 0.01), 12 (p less than 0.01), and 24 (p less than 0.01) h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct ESR Measurement of Free Radicals in Mouse Pancreatic Lesions

SummaryIn this experiment, free radicals in the pancreas of endotoxemia and ethionine induced acute pancreatitis in mice were attempted to be detected directly by ESR spectroscopy, using 77 freeze-trapping and 25 °C DMPO spin trapping techniques. In the 77 K freeze-trapping method, Mn (II) ion and R-00’ radical were detected in endotoxemia and ethionine induced pancreatic lesions. The heme-NO radical was observed at 6 and 24 h after isolation of the normal pancreas, and signal intensity was increased with time. This finding supports that ESR spectroscopy is a useful method for detecting the tissue degeneration process from ischemia to necrosis. Using the DMPO spin trapping technique (25 °C), 6-line was detected at 6 h after intraperitoneal administration ofE. coli in the model of endotoxemia, and 3- and 6-lines and a signal suggestive of DMPO-OH adduct were noted at 12 and 24 h in ethionine pancreatitis. These findings suggest that impaired, pancreatic tissues exist in a considerably oxidative environment and oxygen derived free radicals may be considered to play an important role in the development of pancreatic lesions.

Protective effect of a cephalosporin, Shiomarin, plus a new potent protease inhibitor, E3123, on rat taurocholate‐induced pancreatitis

Abstract The role of infectious factors in the pathogenesis of acute pancreatitis and the protective effect of combined therapy with a new potent synthetic protease inhibitor, E3123, and a new potent synthetic cephalosporin, Shiomarin were examined in rat acute pancreatitis. Sodium taurocholate injection into the pancreatico‐biliary duct of rats caused severe pancreatitis with a high mortality rate, characterized by hyperamylasaemia, high amylase activity in ascitic fluid, hyperendotoxaemia and a high serum level of fibrin degradation products (FDP) and redistribution of cathepsin B from the lysosomal fraction to the zymogen fraction. Sodium taurocholate injection into the pancreatico‐biliary duct also caused the bacterial growth in the pancreas. In rats with E3123 infusion almost all parameters were improved, including mortality rate, serum and ascitic fluid amylase levels, plasma endotoxin and serum FDP levels, and distribution of lysosomal enzyme. But combination therapy with E3123 and Shiomarin was significantly more protective than E3123 therapy alone.

Functional Changes of the Exocrine Perfused Rat Pancreas in Cerulein-Induced Pancreatitis

Functional changes of the exocrine pancreas in cerulein-induced pancreatitis were evaluated with the isolated perfused rat pancreas. In control specimens (n = 7), baseline pancreatic juice volume was 0.23 +/- 0.06 microliter/min and after stimulation with CCK-8 (10(-10) M) and secretin (10(-10) M), it was 2.26 +/- 0.45 microliter/min, and in cerulein-induced pancreatitis specimens (n = 8), the corresponding values were 0.11 +/- 0.03 and 0.23 +/- 0.08 microliter/min. The amylase content in the pancreatic juice (IU/min) was 0.73 +/- 0.15 (baseline) and 7.03 +/- 1.66 (stimulated) in the control specimens, and 0.012 +/- 0.002 (baseline) 0.018 +/- 0.004 (stimulated), in the cerulein-induced pancreatitis specimens. Amylase and lipase concentrations in the portal effluents were significantly higher in the cerulein-induced pancreatitis (481.3 +/- 79.4 IU/ml, 283.7 +/- 47.2 BALB U/ml) than in the control specimens (10.7 +/- 1.8 IU/ml, 8.9 +/- 2.9 BALB U/ml). Using the electron microscope fusion of large vacuoles with lateral plasma membrane was observed in cerulein-induced pancreatitis. In cerulein-induced pancreatitis, normal secretion was markedly decreased, and the lateral secretion was suggested to result in the elevation of pancreatic enzyme levels in portal effluents.

Protective effect of nafamostat mesilate

SummaryThis in vivo and in vitro study demonstrates the protective effects of a new synthetic protease inhibitornafamostat mesilate, FUT-175—on increased cellular and lysosomal fragility within acinar cells during the early stage of cerulein-induced acute pancreatitis in rats. FUT-175 prevented hyperamylasemia, pancreatic edema, congestion owing to amylase, and lactic dehydrogenase (LDH) discharge from acini as well as cathepsin-B leakage from lysosomes dose-dependently in doses of 1-10 mg/kg h. These results suggest that FUT-175 can protect against pancreatitis at subcellular levels in lysosomes and cellular or organelle membranes. Proteases may well play the important role in the pathogenesis of acute pancreatitis, and such a low molecular protease inhibitor may be useful clinically in the treatment of acute pancreatitis.