Mononuclear cells modulate the activity of pancreatic stellate cells which in turn promote fibrosis and inflammation in chronic pancreatitis.

BACKGROUND: Interactions between mononuclear cells and activated pancreatic myofibroblasts (pancreatic stellate cells; PSC) may contribute to inflammation and fibrosis in chronic pancreatitis (CP). METHODS: Markers of fibrosis and inflammation were concomitantly analysed by immunohistochemistry in chronic pancreatitis tissues. In vitro, PSC were stimulated with TNFalpha and LPS. Primary human blood mononuclear cells (PBMC) and PSC were cocultured, followed by analysis of cytokines and extracellular matrix (ECM) proteins. PBMC were derived from healthy donors and CP and septic shock patients. RESULTS: In areas of mononuclear cell infiltration in chronic pancreatitis tissues, there was decreased immunoreactivity for collagen1 and fibronectin, in contrast to areas with sparse mononuclear cells, although PSC were detectable in both areas. LPS and TNFalpha induced collagen1 and fibronectin levels as well as the matrix degradation enzyme MMP-1. Coculture experiments with PSC and PBMC revealed increased fibronectin secretion induced by PBMC. In addition, donor and CP PBMC significantly induced an increase in IL-6, MCP-1 and TGFbeta levels under coculture conditions. Determination of the source of cytokines and ECM proteins by mRNA expression analysis confirmed PSC as major contributors of ECM production. The increase in cytokine expression was PBMC- and also PSC-derived. CONCLUSION: Mononuclear cells modulate the activity of pancreatic stellate cells, which may in turn promote fibrosis and inflammation.

Neurokinin-2 receptor levels correlate with intensity, frequency, and duration of pain in chronic pancreatitis.

OBJECTIVE: Generation and maintenance of pain in chronic pancreatitis (CP) have been shown to be partially attributable to neuroimmune interactions, which involve neuropeptides such as substance P (SP). So far, expression of SP receptors NK-2R, NK-3R, the SP-encoding gene preprotachykinin A (PPT-A), and the SP degradation enzyme neutral endopeptidase (NEP) and their relation to pain in CP have not been determined. METHODS: Tissue samples from patients with CP (n = 25) and from healthy donors (n = 20) were analyzed for PPT-A, NK-2R, NK-3R, and NEP expression using quantitative RT-PCR. NEP protein levels were examined by immunoblot analysis and its localization was determined using immunohistochemistry. A scoring system was used to grade the extent of fibrosis on hematoxylin and eosin- and Masson-Trichrome-stained sections. Messenger RNA levels and the extent of pain were analyzed for correlations. RESULTS: In CP tissues, NK-2R and PPT-A expression was increased, whereas NK-3R and NEP mRNA levels were comparable with normal pancreas. Overexpression of NK-2R was related to the intensity, frequency, and duration of pain in CP patients. NK-1R and NEP expression was significantly related to the extent of fibrosis. CONCLUSIONS: Expression of NK-2R and PPT-A is increased in CP and is associated with pain. Failure to up-regulate NEP may contribute to the disruption of the neuropeptides loop balance in CP and thus may exacerbate the severe pain syndrome.

Preoperative acute pancreatitis in periampullary tumors: implications for surgical management.

BACKGROUND: Pancreatitis is the most serious complication of endoscopic retrograde cholangiopancreatography (ERCP), occurring in 2-20% of the patients. Currently there is no information about the impact of preoperative pancreatitis on the surgical management of periampullary tumors. METHODS: Ten patients with periampullary tumors and preoperative acute pancreatitis were retrospectively analyzed. Four patients who underwent pylorus-preserving pancreaticoduodenectomy (group A) and 6 patients who underwent total pancreatectomy (group B) were compared with a matching control group (age, gender, stage, tumor and operation type) of 30 patients without pancreatitis (group C) who underwent an operation during the same period. Parameters analyzed were C-reactive protein (CRP), leukocytes, aminotransferases, amylase, lipase, operative time, blood loss, hospital stay, morbidity, and mortality. RESULTS: In the study group, 5 patients had pancreatic adenocarcinoma, 3 had distal bile duct cancers, and 2 had ampullary tumors. None of the patients had severe acute necrotizing pancreatitis that necessitated intervention prior to tumor resection. Preoperative median CRP levels in group B were 8.4- and 5.6-fold higher than those of groups A and C, respectively. In contrast, leukocytes, aminotransferases, amylase, and lipase levels were not significantly different. The presence of acute pancreatitis slightly prolonged the duration of the operation (+15 min), increased morbidity (60 vs. 33%) and lengthened median hospital stay (19.5 vs. 14.5 days) in groups A and B vs. group C. All patients with preoperative pancreatitis were managed without mortality. CONCLUSION: Preoperative pancreatitis is more commonly seen in patients with non-pancreatic periampullary tumors, and considerably influences surgical management. High preoperative CRP levels indicate a more severe form of pancreatic damage that may necessitate a total pancreatectomy.

Periostin creates a tumor-supportive microenvironment in the pancreas by sustaining fibrogenic stellate cell activity.

BACKGROUND & AIMS: Pancreatic cancer creates desmoplasia by stimulating stellate cells (PSCs), thereby influencing tumor aggressiveness. The aim of this study was to analyze the impact of the PSC-specific matrix protein periostin on tumor responses to radiochemotherapy. METHODS: PSCs and cancer cells in primary and metastatic lesions of patients treated with or without neoadjuvant radiochemotherapy were evaluated by immunohistochemistry. Periostin messenger-RNA levels determined by quantitative reverse-transcription polymerase chain reaction were correlated to patient survival. Interactions between PSCs and cancer cells and the effects of periostin in modulating cellular responses under conditions of hypoxia, starvation, and radiochemotherapy were assessed by immunoblotting and by growth, clonogenicity, and invasion assays. RESULTS: Periostin messenger-RNA levels were elevated 42-fold in cancer, and patients with increased expression had a tendency toward shorter survival (19 vs 12 months; P = .14). Stromal cells were the only source of periostin in the pancreas and in metastatic sites. Cancer cell supernatants stimulated periostin secretion from PSCs. Recombinant periostin increased alpha-smooth muscle actin, periostin, collagen-1, fibronectin, and transforming growth factor-beta1 expression while decreasing PSC invasiveness. These effects were reversed by silencing periostin expression and secretion by small interfering RNA transfection. In cancer cells, periostin stimulated growth and conferred resistance to starvation and hypoxia. In addition, the periostin downstream target collagen-1 significantly increased chemoresistance. CONCLUSIONS: Once stimulated by cancer cells, PSCs remain active via an autocrine periostin loop even under radiotherapy and produce excessive extracellular matrix proteins, creating a tumor-supportive microenvironment. Increased periostin expression may therefore reflect a more aggressive tumor phenotype.

Surgery for recurrent pancreatic ductal adenocarcinoma.

OBJECTIVE: This study evaluates the outcome of patients who underwent surgery for recurrent pancreatic cancer. SUMMARY BACKGROUND DATA: Recurrence of pancreatic ductal adenocarcinoma occurs in up to 80% of pancreatic cancer patients within 2 years of a potential curative resection because, in most cases, occult (local and/or distant) micrometastases are present at the time of the initial resection. METHODS: Thirty patients were operated for recurrent pancreatic cancer between October 2001 and April 2005. Median time between the initial resection and recurrence was 12.0 months. While 15 patients were resected, 15 patients either underwent palliative bypass or only exploration. Prospectively recorded data were analyzed retrospectively. Survival analysis was performed using Kaplan-Meier estimation and log-rank test. RESULTS: The overall median survival of patients with recurrent disease was 29.0 months. After the first reresection/exploration for recurrent disease, the median survival was 11.4 months. There was a tendency of increased median survival in the group of patients undergoing resection (17.0 months) compared with the bypass/exploration group (9.4 months), although this difference was not significant (P = 0.084). In addition, patients with a prolonged interval (>9 months) from resection to recurrence were more likely to benefit from reresection compared with patients with recurrence within 9 months (median survival 17.0 vs. 7.4 months; P = 0.004). The in-hospital morbidity and mortality rate of resected patients was 20% and 6.7% compared with 13.3% and 0% of patients who underwent only exploration/palliative bypass. CONCLUSION: Resection for recurrent pancreatic cancer can be carried out safely. Further studies are required to address the question whether a subgroup of patients might actually benefit from this procedure.

Pancreatic resection for M1 pancreatic ductal adenocarcinoma.

BACKGROUND: Improved safety of pancreatic surgery has led to consideration of more aggressive approaches, such as resection for primary pancreatic ductal adenocarcinoma (PDAC) with metastatic disease (M1). METHODS: A total of 29 patients who underwent pancreatic resection with resection of associated metastatic disease (interaortocaval lymph node dissection, liver resection, and/or multiorgan resections) were retrospectively identified from a database of 316 R0/R1 pancreatic resections for PDAC. An explorative data analysis of perioperative and clinicopathological parameters, and overall survival was performed by Kaplan-Meier estimation, log rank test, and Fisher's exact test. RESULTS: The overall in-hospital mortality and morbidity of R0/R1 pancreatic resections for M1 disease (n = 29) was 0% and 24.1%, compared with 4.2% and 35.2% of R0/R1 pancreatic resections for M0 disease (n = 287). The median overall survival time was 13.8 months (95% confidence interval [CI], 11.4-20.5), and the estimated 1-year overall survival rate was 58.9% (95% CI, 34.8-76.7) for patients with M1 disease. The median survival in those with metastatic interaortocaval lymph nodes was 27 months (95% CI, 9.6-27.0), whereas it was 11.4 months (95% CI, 7.8-16.5) and 12.9 months (95% CI, 7.2-20.5) for those with liver and peritoneal metastases, respectively. CONCLUSIONS: Pancreatic resections with M1 disease can be performed with acceptable safety in highly selected patients. The survival after interaortocaval lymph node resection is comparable to that of other lymph nodes that do not constitute M1 disease. Resection of liver and peritoneal metastases, although safe in this series, cannot be generally recommended until further controlled trials can be conducted.

Silencing of X-linked inhibitor of apoptosis (XIAP) decreases gemcitabine resistance of pancreatic cancer cells.

BACKGROUND: The X-linked inhibitor of apoptosis (XIAP) belongs to a family of proteins that suppresses apoptosis by inhibition of caspases in some cancers. It confers resistance to apoptosis induction by chemotherapeutic agents. The aim of this study was to evaluate the influence of XIAP in pancreatic cancer. PATIENTS AND METHODS: Tissue samples from 43 patients with pancreatic adenocarcinoma (median age of 67 years, range from 39-81 years) were analyzed. Pancreatic samples from healthy organ donors (10) and chronic pancreatitis patients (10) served as controls. XIAP expression and localization analysis was carried out by quantitative RT-PCR and immunohistochemistry (IHC). XIAP silencing was achieved by transfection of specifically designed siRNA oligonucleotides. Proliferation and chemotherapy experiments were performed by MTT cell growth assays. RESULTS: There was a 2.1-fold increase of median XIAP mRNA levels in pancreatic cancers compared to controls. Kaplan-Meier analysis indicated a tendency for reduced patient survival with increasing levels of XIAP mRNA (higher levels: 13.4 months; lower levels: 16.1 months). IHC revealed strong XIAP staining in tubular complexes and pancreatic cancer cells. XIAP silencing resulted in a slight reduction of the proliferation of Capan-1 and T3M4 pancreatic cancer cells. In addition, XIAP silencing resulted in increased sensitivity of both cell lines to gemcitabine. CONCLUSION: XIAP is overexpressed in pancreatic cancer and contributes to chemoresistance. Interfering with this pathway may have potential therapeutic role in the treatment of this disease.