p21(WAF1) (/Cip1) limits senescence and acinar-to-ductal metaplasia formation during pancreatitis.

Trans-differentiation of pancreatic acinar cells into ductal-like lesions, a process defined as acinar-to-ductal metaplasia (ADM), is observed in the course of organ regeneration following pancreatitis. In addition, ADM is found in association with pre-malignant PanIN lesions and correlates with an increased risk of pancreatic adenocarcinoma (PDAC). Human PDAC samples show down-regulation of p21(WAF1) (/Cip1) , a key regulator of cell cycle and cell differentiation. Here we investigated whether p21 down-regulation is implicated in controlling the early events of acinar cell trans-differentiation and ADM formation. p21-mediated regulation of ADM formation and regression was analysed in vivo during the course of cerulein-induced pancreatitis, using wild-type (WT) and p21-deficient (p21(-/-) ) mice. Biochemical and immunohistochemical methods were used to evaluate disease progression over 2 weeks of the disease and during a recovery phase. We found that p21 was strongly up-regulated in WT acinar cells during pancreatitis, while it was absent in ADM areas, suggesting that p21 down-regulation is associated with ADM formation. In support of this hypothesis, p21(-/-) mice showed a significant increase in number and size of metaplasia. In addition, p21 over-expression in acinar cells reduced ADM formation in vitro, suggesting that the protein regulates the metaplastic transition in a cell-autonomous manner. p21(-/-) mice displayed increased expression and relocalization of ß-catenin both during pancreatitis and in the subsequent recovery phase. Finally, loss of p21 was accompanied by increased DNA damage and development of senescence. Our findings are consistent with a gate-keeper role of p21 in acinar cells to limit senescence activation and ADM formation during pancreatic regeneration.

Pancreatic stone protein predicts positive sputum bacteriology in exacerbations of COPD.

BACKGROUND: Pancreatic stone protein/regenerating protein (PSP/reg) serum levels are supposed to be increased in bacterial inflammation. PSP/reg levels also might be useful, therefore, as a predictor of bacterial infection in COPD. METHODS: Two hundred consecutive patients presenting to the ED due to acute exacerbation of COPD were prospectively assessed. Patients were evaluated based on clinical, laboratory, and lung functional parameters at admission (exacerbation) and after short-term follow-up (14-21 days). PSP/reg serum values were measured by a newly developed enzyme-linked immunosorbent assay. RESULTS: PSP/reg levels were elevated in subjects with COPD exacerbation (23.8 ng/mL; 95% CI, 17.1-32.7) when compared with those with stable disease (19.1 ng/mL; 95% CI, 14.1-30.4; P 5 .03) and healthy control subjects (14.0 ng/mL; 95% CI , 12.0-19.0; P , .01). Higher PSP/reg values were observed in exacerbations with positive sputum bacteriology compared with those with negative sputum bacteriology (26.1 ng/mL [95% CI, 19.2-38.1] vs 20.8 ng/mL [95% CI , 15.6-27.2]; P , .01). Multivariate regression analysis revealed PSP/reg level as an independent predictor of positive sputum bacteriology. A combination of a PSP/reg cutoff value of . 33.9 ng/mL and presence of discolored sputum had a specificity of 97% to identify patients with pathogenic bacteria on sputum culture. In contrast, PSP/reg levels , 18.4 ng/mL and nonpurulent sputum ruled out positive bacterial sputum culture (sensitivity, 92%). In survival analysis, high PSP/reg levels at hospital admission were associated with increased 2-year mortality. CONCLUSIONS: Serum PSP/reg level might represent a promising new biomarker to identify bacterial etiology of COPD exacerbation.

Serotonin regulates amylase secretion and acinar cell damage during murine pancreatitis.

OBJECTIVE: Serotonin (5-hydroxytryptamine, 5-HT) is a potent bioactive molecule involved in a variety of physiological processes. In this study, the authors analysed whether 5-HT regulates zymogen secretion in pancreatic acinar cells and the development of pancreatic inflammation, a potentially lethal disease whose pathophysiology is not completely understood. METHODS: 5-HT regulation of zymogen secretion was analysed in pancreatic acini isolated from wild-type or tryptophan hydoxylase-1 knock-out (TPH1(-/-)) mice, which lack peripheral 5-HT, and in amylase-secreting pancreatic cell lines. Pancreatitis was induced by cerulein stimulation and biochemical and immunohistochemical methods were used to evaluate disease progression over 2 weeks. RESULTS: Absence and reduced intracellular levels of 5-HT inhibited the secretion of zymogen granules both ex vivo and in vitro and altered cytoskeleton dynamics. In addition, absence of 5-HT resulted in attenuated pro-inflammatory response after induction of pancreatitis. TPH1(-/-) mice showed limited zymogen release, reduced expression of the pro-inflammatory chemokine MCP-1 and minimal leucocyte infiltration compared with wild-type animals. Restoration of 5-HT levels in TPH1(-/-) mice recovered the blunted inflammatory processes observed during acute pancreatitis. However, cellular damage, inflammatory and fibrotic processes accelerated in TPH1(-/-) mice during disease progression. CONCLUSIONS: These results identify a 5-HT-mediated regulation of zymogen secretion in pancreatic acinar cells. In addition, they demonstrate that 5-HT is required for the onset but not for the progression of pancreatic inflammation. These findings provide novel insights into the normal physiology of pancreatic acinar cells and into the pathophysiology of pancreatitis, with potential therapeutic implications.

Pancreatic stone protein as an early biomarker predicting mortality in a prospective cohort of patients with sepsis requiring ICU management.

INTRODUCTION: Biomarkers, such as C-reactive protein [CRP] and procalcitonin [PCT], are insufficiently sensitive or specific to stratify patients with sepsis. We investigate the prognostic value of pancreatic stone protein/regenerating protein (PSP/reg) concentration in patients with severe infections. METHODS: PSP/reg, CRP, PCT, tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL1-ß), IL-6 and IL-8 were prospectively measured in cohort of patients ≥ 18 years of age with severe sepsis or septic shock within 24 hours of admission in a medico-surgical intensive care unit (ICU) of a community and referral university hospital, and the ability to predict in-hospital mortality was determined. RESULTS: We evaluated 107 patients, 33 with severe sepsis and 74 with septic shock, with in-hospital mortality rates of 6% (2/33) and 25% (17/74), respectively. Plasma concentrations of PSP/reg (343.5 vs. 73.5 ng/ml, P < 0.001), PCT (39.3 vs. 12.0 ng/ml, P < 0.001), IL-8 (682 vs. 184 ng/ml, P < 0.001) and IL-6 (1955 vs. 544 pg/ml, P < 0.01) were significantly higher in patients with septic shock than with severe sepsis. Of note, median PSP/reg was 13.0 ng/ml (IQR: 4.8) in 20 severely burned patients without infection. The area under the ROC curve for PSP/reg (0.65 [95% CI: 0.51 to 0.80]) was higher than for CRP (0.44 [0.29 to 0.60]), PCT 0.46 [0.29 to 0.61]), IL-8 (0.61 [0.43 to 0.77]) or IL-6 (0.59 [0.44 to 0.75]) in predicting in-hospital mortality. In patients with septic shock, PSP/reg was the only biomarker associated with in-hospital mortality (P = 0.049). Risk of mortality increased continuously for each ascending quartile of PSP/reg. CONCLUSIONS: Measurement of PSP/reg concentration within 24 hours of ICU admission may predict in-hospital mortality in patients with septic shock, identifying patients who may benefit most from tailored ICU management.

COX-2 is not required for the development of murine chronic pancreatitis.

Chronic pancreatitis is a severe inflammation of the pancreas associated with destruction of the parenchyma, fibrosis, and persistent abdominal pain. Cyclooxygenase-2 (COX-2) and COX-2-derived prostaglandins, key mediators of the inflammatory response, are elevated in patients with chronic pancreatitis. Previous studies investigated COX-2 as a therapeutic target. These reports showed a reduced pathology in COX-2-deficient mice with a better outcome. Here we compared the role of COX-2 in acute and chronic pancreatic inflammation using the same COX-2(-/-) mouse model of cerulein-induced pancreatitis. In a setting of acute pancreatitis, juvenile COX-2(-/-) mice exhibited a reduced histopathological score compared with wild-type littermates; on the contrary, adult mice did not show any difference in the development of the disease. Similarly, in a setting of chronic pancreatitis induced over a period of 4 wk, adult mice of the two strains showed comparable histological score and collagen deposition. However, the abundance of mRNAs coding for profibrotic genes, such as collagen, α-smooth muscle actin, and transforming growth factor-ß was consistently lower in COX-2(-/-) mice. In addition, comparable histological scores and collagen deposition were observed in wild-type mice treated with a COX-2 inhibitor. We conclude that, in contrast to what was observed in the rat pancreatitis models, COX-2 has a limited and age-dependent effect on inflammatory processes in the mouse pancreas. These results suggest that COX-2 modulates the inflammatory process during the development of pancreatitis in a species-specific manner. Thus the pathophysiological roles of COX-2 and its therapeutic implications in patients with pancreatitis should be reexamined.

Distribution of macrophages and T cells in syngrafts and allografts after experimental rat lung transplantation.

Macrophages and T cells have a pivotal role in orchestrating the acute lung allograft rejection response. We investigated the spatial and temporal distribution of these immune cells and the synthesis patterns of the T(h)1- and T(h)2-cytokine IL-12 and IL-10 during the early course after transplantation (Tx). Orthotopic single-lung Tx was performed in Lewis to Lewis (syngrafts) and Brown Norway/Lewis F(1) hybrid to Lewis (allografts). Naïve lungs, syngrafts after 5 days and allografts after 3 and 5 days were analyzed for CD68+, CD163+ and CD3+ cells by immunohistochemistry and IL-12 and IL-10 were detected by immunofluorescence. CD68+ macrophages increased in number after allogeneic Tx compared to syngeneic Tx on day 5 (P<.001), CD163+ macrophages sequestrated early around veins (day 3) compared to the accumulation around arteries and bronchioles (P<.001) while CD3+ T cells were scarce. There was a predominance of IL-12 over IL-10 on day 5 after allogeneic Tx (P<.001). CD68+ macrophages were the most abundant cells during acute pulmonary rejection and CD163+ macrophages showed a characteristic distribution pattern over time around vessels and bronchioles. The up-regulation of IL-12 reflects an early response after allo-antigen exposure, indicating a strong impact of the initiation of the T(h)1 pathway at an early phase during acute lung rejection.

The effect of organ-specific CD26/DPP IV enzymatic activity inhibitor-preconditioning on acute pulmonary allograft rejection.

BACKGROUND: Systemic inhibition of serum CD26/dipeptidylpeptidase (DPP IV) enzymatic activity abrogated acute rejection of pulmonary allografts, whereas organ-specific inhibition ameliorated ischemia/reperfusion injury in syngeneic transplants. Here, we analyze the effect of allograft-specific inhibitor preconditioning on acute rejection in the presence of cyclosporine-based immunosuppressive therapy. METHODS: Orthotopic left single lung transplantation (Tx) in rats (LBNF1 to LEWIS). Control (n=5) grafts were flushed with Perfadex alone, whereas treated (n=5) transplants were perfused with Perfadex and AB192, a specific inhibitor of CD26/DPP IV enzymatic activity. All recipients were treated with 2.5 mg of cyclosporine A/kg per day subcutaneously after Tx. Recipients were sacrificed at day 5 after Tx, and oxygenation capacity was measured. In addition, staining for vasoactive intestinal peptide (VIP) and proliferating cell nuclear antigen (PCNA) at explantation (VIP) and at day 5 (VIP, PCNA) was performed with determination of protein levels for PCNA and mRNA for VIP. RESULTS: Grafts from treated versus controls showed significantly increased oxygenation capacity (P<.008), correlating with significantly less acute rejection (P<.02). PCNA staining and protein expression were significantly lower in perivascular and bronchial epithelial cells (P=.001) in treated versus controls. There was significantly higher staining for VIP at the time of Tx in alveolar macrophages in treated versus controls (P=.001), which was seen up to day 5 post-Tx in both macrophages and respiratory epithelium (P=.001) with elevated mRNA expression for VIP in treated animals. CONCLUSION: Perfusion with a specific inhibitor of CD26/DPP IV enzymatic activity was associated with sustained preservation of pulmonary VIP levels, correlating with an amelioration of the acute rejection cascade.

Prostaglandin E2 modulates TNF-alpha-induced MCP-1 synthesis in pancreatic acinar cells in a PKA-dependent manner.

Cyclooxygenase (COX)-2 is increased in human chronic pancreatitis. We recently demonstrated in a model of chronic pancreatitis (WBN/Kob rat) that inhibition of COX-2 activity reduces and delays pancreatic inflammation and fibrosis. Monocyte chemoattractant protein (MCP)-1 mRNA and PGE(2) were significantly reduced, correlating with a decreased infiltration of macrophages. MCP-1 plays an important role in the recruitment of macrophages to the site of tissue injury. The aim of our study is to identify mechanisms by which macrophages and acinar cells maintain an inflammatory reaction. The expression profile of E prostanoid receptors EP(1-4) and MCP-1 was analyzed by RT-PCR from pancreatic specimens and AR42J cells. MCP-1 secretion was detected by ELISA from rat pancreatic lobuli. We determined EP(1-4) mRNA levels in WBN/Kob rats with chronic pancreatic inflammation. Individual isoforms were highly increased in rat pancreas, concurrent with MCP-1 mRNA expression. In supernatants of pancreatic lobuli and AR42J cells, MCP-1 was detectable by ELISA. In the presence of TNF-alpha, MCP-1 was upregulated. Coincubation with PGE(2) enhanced the TNF-alpha-induced MCP-1 synthesis significantly. Similarly, TNF-alpha mRNA was synergistically upregulated by TNF-alpha and PGE(2). Furthermore, the synergistic effect of TNF-alpha and PGE(2) was abolished by inhibition of PKA but not of PKC. We conclude that EP receptors are upregulated during chronic pancreatic inflammation. PGE(2) modulates the TNF-alpha-induced MCP-1 synthesis and secretion from acinar cells. This synergistic effect is controlled by PKA. This mechanism might explain the COX-2-dependent propagation of pancreatic inflammation.