Chronic inflammation initiates multiple forms of K-Ras-independent mouse pancreatic cancer in the absence of TP53.

Chronic inflammation (CI) is a risk factor for pancreatic cancer (PC) including the most common type, ductal adenocarcinoma (PDAC), but its role and the mechanisms involved are unclear. To investigate the role of CI in PC, we generated genetic mouse models with pancreatic specific CI in the presence or absence of TP53. Mice were engineered to express either cyclooxygenase-2 (COX-2) or IκB kinase-2 (IKK2), and TP53+/+ or TP53f/f specifically in adult pancreatic acinar cells by using a full-length pancreatic elastase promoter-driven Cre. Animals were followed for >80 weeks and pancreatic lesions were evaluated histologically and immunohistochemically. The presence of K-ras mutations was assessed by direct sequencing, locked nuclei acid (LNA)-based PCR, and immunohistochemistry. We observed that sustained COX-2/IKK2 expression caused histological abnormalities of pancreas, including increased immune cell infiltration, proliferation rate and DNA damage. A minority of animals with CI developed pre-neoplastic lesions, but cancer was not observed in any TP53+/+ animals within 84 weeks. In contrast, all animals with CI-lacking TP53 developed various subtypes of PC, including acinar cell carcinoma, ductal adenocarcinoma, sarcomatoid carcinoma and neuroendocrine tumors, and all died within 65 weeks. No evidence of K-ras mutations was observed. Variations in the activity of the Hippo, pERK and c-Myc pathways were found in the diverse cancer subtypes. In summary, chronic inflammation is extremely inefficient at inducing PC in the presence of TP53. However, in the absence of TP53, CI leads to the development of several rare K-ras-independent forms of PC, with infrequent PDAC. This may help explain the rarity of PDAC in persons with chronic inflammatory conditions.

The imbalance between matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 in acute pancreatitis.

BACKGROUND: The balanced activity of matrix metalloproteinases and their tissue inhibitors is an important, albeit still not completely understood, determinant of extracellular matrix homeostasis, a factor involved in the pathogenesis of acute pancreatitis (AP). AIMS: The aim of this study was to compare serum concentrations of matrix metalloproteinase 9 (MMP-9) and its tissue inhibitor (TIMP-1) in patients with AP of various severity and to investigate their relationship with prognostic indicators of AP severity, e.g., polymorphonuclear leukocyte elastase (PMN-E). PATIENTS AND METHODS: The study included 37 patients with mild (n = 18) or severe AP (n = 19) and 15 healthy controls. Serum concentrations of MMP-9 and TIMP-1 were determined on admission (day 1) and on days 2, 3, 5 and 10. RESULTS: Throughout the study period, the serum MMP-9 concentration in patients with severe AP was significantly higher than those in individuals with mild AP and in healthy controls. In turn, the serum MMP-9 concentrations in persons with mild AP did not differ significantly from those of the controls. The serum TIMP-1 concentrations in both groups were significantly higher than in the controls. Beginning from the 2(nd) day of hospital stay, the serum TIMP-1 concentration in patients with severe AP was significantly higher than in individuals with mild AP. There were significant correlations between: MMP-9 and PMN-E, TIMP-1 and PMN-E, and MMP-9 and TIMP-1. CONCLUSION: A disturbed balance between MMP-9 and TIMP-1 observed during the early stages of severe AP suggests that endogenous TIMP-1 is unable to prevent excessive activation and release of MMP-9. MMP-9 may represent a new marker of AP severity.

Complications of endoscopic retrograde cholangiopancreatography (ERCP) and their risk factors.

PURPOSE: Determination of the type and frequency of complications developing after diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP) as well as the risk factors predisposing to them. MATERIAL/METHODS: The retrospective study, including 734 ERCP performed in 550 patients, with 404 (55%) ES (endoscopic sphincterotomy) during a 4-year period. RESULTS: Among 734 ERCP procedures, 76.4% (561) had both diagnostic and therapeutic purpose, 15.2% (112) were only diagnostic. Complications developed after 26 procedures (3.5%): acute pancreatitis (AP) in 8 patients (1.09%), cholangitis in 7 (0.95%) and delayed bleeding in 11 (1.5%) patients. After 49 (6.7%) ES immediate bleeding was observed. The risk factors for AP were: unintentional pancreatic duct contrasting, mechanical lithotripsy, the use of the "pre-cut" technique and bile duct dilatation. Cholangitis was more common in cases with difficult cannulation at older age and with lower baseline bilirubin level. The risk factors for delayed bleeding were: location of the ampulla of Vater in the diverticulum and the use of the "precut" technique. Immediate bleeding was more frequent after revision of bile ducts with Dormia's basket or with balloon, after introduction of contrast medium to the pancreatic duct or in ductal cholelithiasis. CONCLUSIONS: ERCP performed in the endoscopy unit of a specialist hospital department is a relatively safe procedure, with a low burden of complications as compared to the benefits it provides to appropriately qualified patients.