Influence of molecule CD 11b blockade on the course of acute ceruleine pancreatitis in rats

CXCR2 inhibition suppresses acute and chronic pancreatic inflammation

Pancreatitis is a significant clinical problem and the lack of effective therapeutic options means that treatment is often palliative rather than curative. A deeper understanding of the pathogenesis of both acute and chronic pancreatitis is necessary to develop new therapies. Pathological changes in pancreatitis are dependent on innate immune cell recruitment to the site of initial tissue damage, and on the coordination of downstream inflammatory pathways. The chemokine receptor CXCR2 drives neutrophil recruitment during inflammation, and to investigate its role in pancreatic inflammation, we induced acute and chronic pancreatitis in wild-type and Cxcr2(-/-) mice. Strikingly, Cxcr2(-/-) mice were strongly protected from tissue damage in models of acute pancreatitis, and this could be recapitulated by neutrophil depletion or by the specific deletion of Cxcr2 from myeloid cells. The pancreata of Cxcr2(-/-) mice were also substantially protected from damage during chronic pancreatitis. Neutrophil depletion was less effective in this model, suggesting that CXCR2 on non-neutrophils contributes to the development of chronic pancreatitis. Importantly, pharmacological inhibition of CXCR2 in wild-type mice replicated the protection seen in Cxcr2(-/-) mice in acute and chronic models of pancreatitis. Moreover, acute pancreatic inflammation was reversible by inhibition of CXCR2. Thus, CXCR2 is critically involved in the development of acute and chronic pancreatitis in mice, and its inhibition or loss protects against pancreatic damage. CXCR2 may therefore be a viable therapeutic target in the treatment of pancreatitis.

Patients with acute pancreatitis complicated by organ dysfunction show abnormal peripheral blood polymorphonuclear leukocyte signaling

BACKGROUND/OBJECTIVES

Circulating polymorphonuclear leukocytes (PMNLs) may contribute to development of organ dysfunction in acute pancreatitis (AP). We outlined aberrations in PMNL signaling profiles in patients with AP complicated by organ dysfunction and immune suppression.

METHODS

Study comprised 13 patients treated at intensive care unit due to severe AP complicated by vital organ dysfunction. Mean proportion (SEM) of HLA-DR-positive monocytes was 55.0% (4.1%). 13 healthy volunteers served as reference subjects. Phosphorylation of PMNL NFκB, p38, ERK1/2 and STAT3, -5 and -6 was determined using whole blood flow cytometry. Transmigration of PMNLs was studied using endothelial EA-HY cell monolayer.

RESULTS

Proportions of NFκB phosphorylation-positive PMNLs were lower in the patients' than in reference subjects' blood samples supplemented with tumor necrosis factor. p38 phosphorylation was normal while ERK1/2 phosphorylation was decreased. STAT3 was constitutively activated in five patients. Proportion of patients' pSTAT6-positive cells was normal while fluorescence intensity was decreased. STAT5 phosphorylation was normal. Transmigration of patients' PMNLs was increased.

CONCLUSIONS

In patients with AP complicated by organ dysfunction proportion of pNFκB-positive PMNLs is decreased. This impairs patients' defense mechanisms against infection. Despite immune suppression, PMNL transmigration was increased and p38 phosphorylation capacity was not depressed, which may contribute to end organ inflammation and dysfunction.

Neutrophil engagement and septic challenge in acute experimental pancreatitis in rats

AIM: To investigate the influence of neutrophil adhesion molecule blockade with monoclonal antibody (MoAb CD11b) and E. coli lipopolysaccharide (LPS) administration on experimental acute pancreatitis (AP).

METHODS: AP was induced by four ip injections of cerulein (Cn) at 1-h intervals. MoAb CD 11b and LPS were administered at the beginning of the experiment.

RESULTS: The neutrophil count and chemiluminescence were diminished at the beginning of AP. The oxidative stress parameters were found within the pancreatic gland. MoAb CD 11b used for AP resulted in a significant reduction of pancreatic infiltration and pancreatitis oxidative stress parameters. Serum interleukin-6 (IL-6) was not detected in AP animals, whereas high serum IL-6 concentration was noted only in animals receiving LPS.

CONCLUSION: Neutrophils are involved in pancreatic damage in the early stage of AP. Neutrophil infiltration reduction protects the pancreatic gland from destruction during AP. LPS does not change the early course of Cn pancreatitis in rats.