Oxidative stress in rodent closed duodenal loop pancreatitis

Cerium-based histochemical demonstration of oxidative stress in taurocholate-induced acute pancreatitis in rats. A confocal laser scanning microscopic study

Direct in vivo histological detection of oxygen-derived free radicals (OFRs) in inflammatory conditions is not fully resolved. We report an application of cerium histochemistry (in which capture of OFRs by Ce atoms results in laser-reflectant cerium-perhydroxide precipitates) combined with reflectance confocal laser scanning microscopy (CLSM) to demonstrate the evolution of oxidative stress in taurocholate-induced acute pancreatitis (AP) in rats. Animals were perfused with CeCl(3) in vivo and cryostat sections of pancreata were studied by CLSM. Vascular endothelium was immunolabeled for PECAM-1. OFR production by isolated polymorphonuclear leukocytes (PMNs) incubated in vitro with CeCl(3) was quantified by image analysis. In the pancreas, strong OFR-derived cerium reflectance signals were seen in acinar cells at 1-2 hr, capillaries and small venules were frequently engorged by cerium precipitates, and adherent PMNs presented weak intracellular reflectance signals. At 8-24 hr, acinar cell OFR production decreased, whereas adherent/transmigrated PMNs displayed abundant intra- and pericellular reflectance. PECAM-1 expression was unchanged. PMNs from ascites or blood showed significant (p<0.01) time-dependent OFR production, plateauing from 2 hr. The modified cerium capture/CLSM method allows the co-demonstration of in vivo oxidative stress and cellular structures labeled with fluorescent markers. In vivo oxidative stress was shown histologically for the first time in experimental AP.

[Effect of selenium administration on various laboratory parameters in patients with acute pancreatitis]

BACKGROUND

Recent studies presented evidence that activation of oxygen derived free radicals occurs in patients with acute pancreatitis. The purpose of this study was to evaluate the effect of sodium selenite as a possible antioxidant therapy in acute pancreatitis.

PATIENTS AND METHOD

16 patients with moderate form of acute pancreatitis received a high dose of sodium selenite. Selenium in serum and whole blood, zinc, copper, manganese, superoxid dismutase (SOD), glutathione peroxidase (Gpx) and malondialdehyde (MDA) were determined (before selenium substitution, 3 days later, 8 days later, before demission). No selenium deficiency could be detected before selenium substitution.

RESULT

The selenium therapy caused a significant increase in selenium, a moderate increase in activity of Gpx, a significant decrease in activity of MDA, whereas SOD remained unchanged.

CONCLUSION

Concerning the particular point of view of "deficiency management", there is no need of selenium substitution in patients with a moderate form of acute pancreatitis in our region. The highly normal selenium concentration we established by our therapy is possibly connected with a decrease of the oxidative stress in acute pancreatitis. More clinical follow-up studies with more patients, who have different grades of severity of the acute pancreatitis, and besides that a control group of patients without selenium substitution, are necessary for evaluating the clinical relevance of our results.

Role of hypertriglyceridemia in the pathogenesis of experimental acute pancreatitis in rats

CONCLUSION

The pancreatic damage initiated via different pathogenetic pathways can be increased by triglycerides. Thus, triglycerides seem to play an important role in the pathogenesis of acute pancreatitis.

BACKGROUND

Lipolytic enzymes and their substrates may play a role in the pathogenesis of acute necrotizing pancreatitis. We investigated, therefore, whether triglycerides alter the course of acute pancreatitis in three experimental models of rats.

METHODS

1. Edematous acute pancreatitis induced by repeated sc injections of cerulein; 2. Necrotizing acute pancreatitis by retrograde duct injection of sodium taurocholate; and 3. Pancreatic edema by ligation of: a. The bile duct at the liver hilus; b. The common bile/pancreatic duct close to the duodenal wall; or c. A combination of a. and b. Six hours later, rats were sacrificed and the isolated perfused pancreas prepared. The pancreases were perfused with either HEPES/Ringer/HAES alone or in combination with various concentrations of triglycerides (1-5% wt/vol). The activities of lipase and amylase in the portal venous effluents were regarded as a marker of pancreatic injury. In addition, the pancreases were evaluated by light microscopy.

RESULTS

In both cerulein and taurocholate acute pancreatitis, amylase/lipase activities were significantly higher compared to controls during 45 min of perfusion. In both models, addition of triglycerides caused a dose-dependent marked elevation of enzymes. Ligation (a) did not cause any rise in enzymes in the venous effluent; triglycerides had no effect. Ligation (b) or (c) caused a significant increase of pancreatic enzymes, which was further increased by triglycerides. Histology showed various degrees of severity of tissue damage depending on the model used. The additional damaging effect of a 45-min perfusion with triglycerides, however, could not be detected by histology.