Fasting exacerbates acute pancreatitis by occlusion of the common bile duct in rats

FASTING INCREASES THE SEVERITY OF ACUTE PANCREATITIS IN A MOUSE MODEL: IMPLICATIONS FOR PREOPERATIVE INTERVENTIONS TO REDUCE COMPLICATIONS OF PANCREATIC SURGERY

BACKGROUND

Acute pancreatitis following surgical or endoscopic procedures on the pancreas can compromise the outcome and lead to severe complications and even death. The aim of this study was to determine whether prolonged fasting affects the severity of acute pancreatitis (AP).

METHODS

Male mice were divided into 4 groups: Group CF (n=5) control animals that fasted for 24 hours; Group CNF (n=5) control animals that did not fast; Group APF (n=7) that fasted for 24 hours and underwent induction of acute pancreatitis (AP) and Group APNF (n=7) that did not fast and underwent AP. Eight hours after AP blood was collected for evaluation of cytokines: IL-1β, IL-6, IL-10, TNF-α and MCP-1. Liver tissue was collected for determination of Malondialdehyde, pancreatic tissue for determination of enzyme content and lung tissue for determination of myeloperoxidase.

RESULTS

Significant increase in pancreatic amylase content was observed in group CF and increased serum levels of IL -6, Il-10 and MCP-1 were in group APF. Liver malondialdehyde was also increased in APF animals. APF group showed much more necrosis of the pancreatic acinar cells.

CONCLUSION

In the present study, we observed an increase in the severity of acute pancreatitis with prolonged fasting in a severe acute pancreatitis model. These results suggest that in clinical practice, the preoperative fasting time should be shortened before pancreatic procedures.

Evaluation of miR-216a and miR-217 as potential biomarkers of acute pancreatic injury in rats and mice

Mild injury of the exocrine pancreas is often asymptomatic and can be under- or mis-diagnosed. The pancreas-enriched microRNAs miR-216a and miR-217 were evaluated as potential serum biomarkers of exocrine pancreas injury in rodent models of acute pancreatitis induced by caerulein, l-arginine, and pancreatic duct ligation. Both microRNAs showed time- and dose- relevant responses to pancreatic injury and wider dynamic ranges of response than serum amylase or lipase. Pancreas-selective microRNAs were found to be relatively sensitive serum biomarkers of pancreatic injury in rodents with potentially greater specificity than the current standard assays.

The effect of N-acetylcysteine on pulmonary lipid peroxidation and tissue damage

BACKGROUND

We aimed to investigate the effect of N-acetylcysteine (NAC) on pulmonary lipid peroxidation and tissue damage in experimental obstructive jaundice (OJ) stimulated by lipopolysaccharide (LPS) in this study.

MATERIALS AND METHODS

We randomized 40 rats into five groups. Group A: Sham (n = 8); group B: OJ (n = 8); group C: OJ + lipopolysaccharide (LPS; n = 8); group D: OJ + NAC + LPS (n = 8); group E: OJ + LPS + NAC (n = 8). OJ was performed by common bile duct ligation and division in all groups except the sham group. At the fifth day, the rats were jaundiced. At the fifth day of OJ, LPS was injected 10 mg/kg intraperitoneally to the rats and at the tenth day, the rats were sacrificed in group C. In group D; at the fifth day of OJ, NAC was started 100 mg/kg subcutaneously and the same dose NAC injection repeated every day for 5 days. At the tenth day of OJ, LPS was injected 10 mg/kg intraperitoneally to the rats and then after 6 h they were sacrificed. In group E; 10 mg/kg LPS was administered intraperitoneally at fifth day of OJ and after then NAC was started 100 mg/kg subcutaneously and the same dose NAC injection repeated every day for 5 days and at the tenth day, the rats were sacrificed. Tissue samples were harvested through a midline incision, and lungs were resected and examined histopathologically and immunohistochemically for tissue damage scoring. The blood was taken by cardiac puncture and malondialdehyde (MDA), myeloperoxidase (MPO), and levels of total antioxidant status were detected with biochemical methods to evaluate lung tissue damage.

RESULTS

Increase in lung and serum MDA and MPO levels, as well as decrease in total antioxidant status, were observed in groups B and C when compared with the sham group (P = 0.0001, for each comparison). Furthermore, the lung tissue damage was observed in the same groups by histopathological examination when compared with sham group. There was significant decrease at serum and lung MPO and MDA levels after the NAC application in groups D and E, when compared with group C (P = 0.0001, for each comparison). Antioxidant status in groups D and E were increased in the presence of NAC (P = 0.0001, for each comparison). Lung histology was prevented relatively in group D when compared with groups B and C.

CONCLUSION

Results of the study indicate that NAC has protective effect on pulmonary lipid peroxidation and tissue damage before and after LPS administration.

Effects of octreotide pretreatment in experimental acute pancreatitis

BACKGROUND

Severity of systemic lesions and mortality of experimental acute pancreatitis (AP) are reduced after pancreatic enzyme content reduction induced by cerulein administration. Octreotide has been used both prophylatically and therapeutically in AP. The possible effects of octreotide on pancreatic enzyme content and its influence on pulmonary lesions of experimental AP were assessed in this study.

METHODS

Wistar male rats were divided in two branches: BRANCH I - Animals divided into three groups: Group Sa (n = 10) intravenous saline infusion; Group Ce (n = 10) intravenous cerulein infusion, (0.133 micro g/kg(-1).h(-1)) and Group Oc (n = 10) SC octreotide (10 micro g/kg(-1)). Trypsin, elastase and amylase pancreatic contents as well as serum amylase were determined thereafter in all three groups; BRANCH II - Rats treated as in branch I, were submitted to sodium taurocholate AP (Groups Sa+AP, Ce+AP and Oc+AP). Two hours thereafter amylase and TAP assays were performed in serum, ascites and pancreatic tissue in eight animals of each group. Pulmonary histology was studied by morphometry 24 h after AP in the remaining animals.

RESULTS

Increased serum amylase and pancreatic enzyme contents were observed in octreotide-treated animals when compared to animals receiving saline or cerulein. After AP increases of serum and ascitic fluid amylase and of pancreatic TAP were observed in octreotide pre-treated animals when compared to saline and cerulein groups. Pulmonary interstitial and alveolar edema after AP was significantly increased in rats receiving octreotide as compared to the cerulein group.

CONCLUSION

Octreotide administration acutely increases the enzymatic content of the pancreas and thus may have a potential deleterious influence in the evolution of AP.

Contribution of circulating leukocytes to cytokine production in pancreatic duct obstruction-induced acute pancreatitis in rats

Little information is available regarding the role of circulating leukocytes in the pathogenesis of acute pancreatitis (AP). Our aim was to explore the time-course of the potential role of inflammatory peripheral blood (PB) cells during AP induced in rats by pancreatic duct obstruction (PDO). Flow cytometry immunophenotyping was used to analyse the distribution of the major circulating leukocyte subsets, the activation state of circulating monocytes as reflected by both CD11b expression and TNF-alpha production and the relative contribution of T-cell derived pro- (TNF-alpha) and anti- (IL-10) inflammatory mediators at different stages of PDO-induced AP. A progressive increase in PB neutrophils and monocytes was observed up to 6h after PDO whereas lymphocytes, as well as CD4(+) and CD8(+) T-cell subsets, rose as early as 1.5 h after PDO and decreased thereafter. Monocytes were activated in PB from 6 h after inducing AP as reflected by increases in both CD11b expression and spontaneous TNF-alpha production; nevertheless, they showed the capability of producing TNF-alpha at earlier AP stages by lipopolysaccharide (LPS) stimulation. In contrast, T-cells were unable to produce TNF-alpha during AP neither spontaneously nor after stimulation with PMA/Ionomycin. Therefore, only PB monocytes contribute to increase TNF-alpha levels in plasma as observed from 12 h onwards after inducing AP. Interleukin-10 was produced by T-cells 6 h after PDO only after PMA/Ionomycin stimulation. We conclude that systemic inflammatory events are triggered off at early stages of PDO-induced AP, with the activation of circulating monocytes, though not T-cells, playing a central role.