Pathogenesis of infection in pancreatic inflammatory disease

Do the effects of pentoxifylline on the inflammatory process and pancreatic infection justify its use in acute pancreatitis?

Severe acute pancreatitis is associated with high morbidity and mortality rates. At the present time, no specific therapy has been shown to be uniformly effective in reducing morbidity and mortality in this disease. The aim of this study was to determine the effects of pentoxifylline on the pancreatic and systemic inflammatory process, pancreatic infection, and mortality rate in severe acute pancreatitis in rats.

METHODS

One hundred and twenty male Wistar rats were divided into 3 groups: sham, pancreatitis, and pentoxifylline (acute pancreatitis induction plus administration of 25 mg/kg pentoxifylline). Inflammatory response was measured by histological studies, inflammatory cytokine production (IL-6, IL-10, and TNF-alpha), and mortality rate. Pancreatic infection was evaluated by bacterial cultures expressed in colony-forming units per gram.

RESULTS

Pentoxifylline-treated animals had a statistically significant reduction of inflammatory cytokine levels, pancreatic histological damage, occurrence of bacterial translocation and pancreatic infection (p < 0.05), associated with a significant reduction in mortality rate.

CONCLUSIONS

Pentoxifylline administration in this experimental model of acute pancreatitis reduces local and systemic inflammatory responses and decreases the pancreatic infection and the mortality rate.

Effect of inhibition of prostaglandin E2 production on pancreatic infection in experimental acute pancreatitis

OBJECTIVE

Acute pancreatitis is one the important causes of systemic inflammatory response syndrome (SIRS). SIRS results in gut barrier dysfunction that allows bacterial translocation and pancreatic infection to occur. Indomethacin has been used to reduce inflammatory process and bacterial translocation in experimental models. The purpose of this study was to determine the effect of inhibition of prostaglandin E2 (PGE2) production on pancreatic infection.

MATERIALS AND METHODS

An experimental model of severe acute pancreatitis (AP) was utilized. The animals were divided into three groups: sham (surgical procedure without AP induction); pancreatitis (AP induction); and indomethacin (AP induction plus administration of 3 mg/kg of indomethacin). Serum levels of interleukin (IL)-6 and IL-10, PGE2, and tumor necrosis factor (TNF)-alpha were measured 2 h after the induction of AP. We analyzed the occurrence of pancreatic infection with bacterial cultures performed 24 h after the induction of AP. The occurrence of pancreatic infection (considered positive when the CFU/g was >105), pancreatic histologic analysis, and mortality rate were studied.

RESULTS

In spite of the reduction of IL-6, IL-10, and PGE2 levels in the indomethacin group, TNF-alpha level, bacterial translocation, and pancreatic infection were not influenced by administration of indomethacin. The inhibition of PGE2 production did not reduce pancreatic infection, histologic score, or mortality rate.

CONCLUSION

The inhibition of PGE2 production was not able to reduce the occurrence of pancreatic infection and does not have any beneficial effect in this experimental model. Further investigations will be necessary to discover a specific inhibitor that would make it possible to develop an anti-inflammatory therapy.

Role of Toll-like receptor 4 on pancreatic and pulmonary injury in a mice model of acute pancreatitis associated with endotoxemia

OBJECTIVE

Infection of pancreatic necrosis is a severe complication of acute pancreatitis. Because Toll-like receptor 4 (TLR4) has been identified as a receptor necessary to transduct the signal of bacteria-derived lipopolysaccharide into cells, we investigated the role of TLR4 on pancreatic and pulmonary injury in acute pancreatitis and acute pancreatitis associated with endotoxemia in wild-type and TLR4-deficient mice.

DESIGN

Laboratory investigation.

SETTING

University laboratory.

SUBJECTS

Heterozygous TLR4 mice.

INTERVENTIONS

Mice were injected intraperitoneally with a supramaximal dose of cerulein each hour for 10 hrs. To mimic infection, additional groups of mice were injected with lipopolysaccharide in the presence or absence of cerulein injections.

MEASUREMENTS AND MAIN RESULTS

The severity of acute pancreatitis was assessed by serum amylase activity, pancreatic edema, acinar cell necrosis, and pancreas myeloperoxidase activity. Lung injury was quantitated by lung microvascular permeability and lung myeloperoxidase activity. Injections of cerulein induced an edematous pancreatitis that was of similar severity in wild-type and TLR4-deficient mice. Lipopolysaccharide alone had no toxic effect on pancreas and lungs and did not worsen the pancreatic injury induced by cerulein in wild-type and TRL4-deficient mice. In contrast, lipopolysaccharide worsened pancreatitis-associated lung injury, and the deficiency in TLR4 fully prevented this aggravation.

CONCLUSIONS

TLR4 may not play a role in the pancreatitis-associated lung injury but participates in the pulmonary injury mediated by endotoxemia.