MCP-1 but not CINC synthesis is increased in rat pancreatic acini in response to cerulein hyperstimulation

Resveratrol pre-treatment alleviated caerulein-induced acute pancreatitis in high-fat diet-feeding mice via suppressing the NF-κB proinflammatory signaling and improving the gut microbiota

BACKGROUND

hyperlipidemia acute pancreatitis (HTG-AP) is a major hidden danger affecting human health, however, whether there is a protective effect of resveratrol on HTG-AP is unclear. Therefore our study was aimed to investigate the preventive effect and the underlying mechanism of resveratrol in the HTG-AP mice model.

METHODS

This research was divided into two parts. In the first part, mice were adaptively fed with normal chow or HFD for 6 weeks. From the second week, resveratrol-treated mice were in intragastric administration with resveratrol (45 mg/kg/d) for 4 weeks. In the second part, the procedures were the same as the first part. After the last intragastric administration with resveratrol, all mice were intraperitoneal injections of cerulean.

RESULTS

We found resveratrol effectively inhibited pancreatic pathological injury in the HFD, AP, and HTG-AP mice. Resveratrol reduced the LPS, IL-6, TNF-α, and MCP-1 expressions in the HFD mice. Resveratrol also reduced TNF-α, MDA, and MCP-1 expressions and increased SOD and T-AOC expressions in the AP and HTG-AP mice. Furthermore, resveratrol suppressed the NF-κB pro-inflammatory signaling pathway in pancreatic tissues in the AP and HTG-AP mice. Moreover, resveratrol improved the gut microbiota in the HFD mice.

CONCLUSION

The resveratrol pre-treatment could attenuate pancreas injury, inflammation, and oxidative stress in the HTG-AP mice, via restraining the NF-κB signaling pathway and regulating gut microbiota. Therefore, Our study proved that the resveratrol pre-treatment had a preventive effect on HTG-AP.

Serum TLR9 and NF-κB Biochemical Markers in Patients with Acute Pancreatitis on Admission

Aim

The aim of this study was to investigate the serum TLR9 and NF-κB levels in patients for the diagnosis and prognostication of AP in the emergency department.

Methods

In the current study, we looked at the TLR9 and NF-κB levels in patients for the diagnosis and prognostication of AP in the emergency department.

Results

Of the patients with acute pancreatitis, 22 (49%) were male and 23 (51%) were female. The mean age of the patient group was 62 years, with a range of 25-95 years. The control group consisted of 19 (43.1%) male and 25 (56.9%) female patients. The serum TLR9 and NF-κB levels in patients for the diagnosis and prognostication of AP in the emergency department. p < 0.001 and 8.04 ± 1.76 vs. 4.76 ± 1.13; p < 0.001 and 8.04 ± 1.76 vs. 4.76 ± 1.13; κB levels in patients for the diagnosis and prognostication of AP in the emergency department. p < 0.001 and 8.04 ± 1.76 vs. 4.76 ± 1.13; κB levels in patients for the diagnosis and prognostication of AP in the emergency department. p < 0.001 and 8.04 ± 1.76 vs. 4.76 ± 1.13.

Conclusion

We demonstrated that the TLR9 and NF-κB pathway is activated in acute pancreatitis and increases the inflammatory process. This may help to further understand the pathogenesis of disorder, diagnosis, and clinical severity. We proposed that blockage of these inflammatory pathways may play a role in the prevention of the disease progression and development of inflammatory complications.κB levels in patients for the diagnosis and prognostication of AP in the emergency department.

Chemokine CXCL16 mediates acinar cell necrosis in cerulein induced acute pancreatitis in mice

Severe acute pancreatitis is a lethal inflammatory disease frequently accompanied by pancreatic necrosis. We aimed to identify a key regulator in the development of pancreatic necrosis. A cytokine/chemokine array using sera from patients with acute pancreatitis (AP) revealed that serum CXCL16 levels were elevated according to the severity of pancreatitis. In a mouse model of AP, Cxcl16 expression was induced in pancreatic acini in the late phase with the development of pancreatic necrosis. Cxcl16^-/- mice revealed similar sensitivity as wild-type (WT) mice to the onset of pancreatitis, but better resisted development of acinar cell necrosis with attenuated neutrophil infiltration. A cytokine array and immunohistochemistry revealed lower expression of Ccl9, a neutrophil chemoattractant, in the pancreatic acini of Cxcl16^-/- mice than WT mice. Ccl9 mRNA expression was induced by stimulation with Cxcl16 protein in pancreatic acinar cells in vitro, suggesting a Cxcl16/Ccl9 cascade. Neutralizing antibody against Cxcl16 ameliorated pancreatic injury in the mouse AP model with decreased Ccl9 expression and less neutrophil accumulation. In conclusion, Cxcl16 expressed in pancreatic acini contributes to the development of acinar cell necrosis through the induction of Ccl9 and subsequent neutrophil infiltration. CXCL16 could be a new therapeutic target in AP.

In vitro secretion of zymogens by bovine pancreatic acini and ultra-structural analysis of exocytosis

The aim of this study is to establish a bovine pancreatic acinar cell culture model with longer viability and functionality. The cells could be maintained in a functional state for upto 20 days with normal morphology. Cells were positive for amylase as observed by immunofluorescence staining. Acinar cells are spherical and range about 2–3 µm in diameter. The porosome formed by exocytosis and heterogenous enzyme granules of size ranging 100–300 nm were seen on the surface of cells by electron microscopy. The activity of the enzymes was high on day 15 and the activity profile of the enzymes is in the order: protease>lipase>amylase and the enzymes were identified by SDS-PAGE. Long-term culture of bovine pancreatic acini could be useful in studying the pathogenesis of pancreatitis. Since the bovine genome shares about 80% identity with the human genome, the cells derived from bovine pancreas can be engineered and used as a potential xenotransplant to treat conditions like pancreatitis as the tissue source is abundantly available.

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Acinar cells are functional unit of pancreas.

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In vitro release of enzyme granules by exocytosis are well demonstrated.

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Amylase shares 86% protein identity with that of human.

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Acinar culture showed longer viability upto 20 days with normal cellular function.

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Useful culture model in understanding the acinar cell biology and physiology.

Redox signaling in acute pancreatitis

Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On the other hand, the release of extracellular hemoglobin into the circulation from the ascitic fluid in severe necrotizing pancreatitis enhances lipid peroxidation in plasma and the inflammatory infiltrate into the lung and up-regulates the HIF-VEGF pathway, contributing to the systemic inflammatory response. Therefore, redox signaling and oxidative stress contribute to the local and systemic inflammatory response during acute pancreatitis.

Redox signaling and histone acetylation in acute pancreatitis

Histone acetylation via CBP/p300 coordinates the expression of proinflammatory cytokines in the activation phase of inflammation, particularly through mitogen-activated protein kinases (MAPKs), nuclear factor-κB (NF-κB), and signal transducers and activators of transcription (STAT) pathways. In contrast, histone deacetylases (HDACs) and protein phosphatases are mainly involved in the attenuation phase of inflammation. The role of reactive oxygen species (ROS) in the inflammatory cascade is much more important than expected. Mitochondrial ROS act as signal-transducing molecules that trigger proinflammatory cytokine production via inflammasome-independent and inflammasome-dependent pathways. The major source of ROS in acute inflammation seems to be NADPH oxidases, whereas NF-κB, protein phosphatases, and HDACs are the major targets of ROS and redox signaling in this process. There is a cross-talk between oxidative stress and proinflammatory cytokines through serine/threonine protein phosphatases, tyrosine protein phosphatases, and MAPKs that greatly contributes to amplification of the uncontrolled inflammatory cascade and tissue injury in acute pancreatitis. Chromatin remodeling during induction of proinflammatory genes would depend primarily on phosphorylation of transcription factors and their binding to gene promoters together with recruitment of histone acetyltransferases. PP2A should be considered a key modulator of the inflammatory cascade in acute pancreatitis through the ERK/NF-κB pathway and histone acetylation.

Acute pancreatitis due to diabetes: the role of hyperglycaemia and insulin resistance

BACKGROUND

The co-existence of diabetes mellitus (DM) in patients with acute pancreatitis (AP) is linked to poor outcomes. Four large epidemiological studies have suggested an aetiological role for DM in AP. The exact nature of this role is poorly understood.

OBJECTIVE

To analyse the available clinical and experimental literature to determine if DM may play a causative role in AP.

METHODS

A systematic search of the scientific literature was carried out using EMBASE, PubMed/MEDLINE, and the Cochrane Central Register of Controlled Trials for the years 1965-2011 to obtain access to all publications, especially randomized controlled trials, systematic reviews, and meta-analyses exploring the mechanisms of pathogenesis of AP in patients with DM.

RESULTS

No clinical studies could be identified directly providing pathogenetic mechanisms of DM in the causation of AP. The available data on DM and its associated metabolic changes and therapy indicate that hyperglycaemia coupled with the factors influencing insulin resistance (tumour necrosis-α, NFκB, amylin) cause an increase in reactive oxygen species generation in acinar cells.

CONCLUSIONS

Complex pathogenetic connections exist between AP and factors involved in the development and therapy of DM. Insulin resistance and hyperglycaemia, hallmarks of DM, are important factors linked to the susceptibility of diabetics to AP. Given the high morbidity associated with an attack of AP in a diabetic patient, targeting these two aspects by therapy may help not only to reduce the risk of development of AP, but may also help reduce the severity of an established attack in a diabetic patient.

Oxidative and nitrosative stress in acute pancreatitis. Modulation by pentoxifylline and oxypurinol

Reactive oxygen species are considered mediators of the inflammatory response and tissue damage in acute pancreatitis. We previously found that the combined treatment with oxypurinol - as inhibitor of xanthine oxidase- and pentoxifylline - as inhibitor of TNF-α production-restrained local and systemic inflammatory response and decreased mortality in experimental acute pancreatitis. Our aims were (1) to determine the time-course of glutathione depletion and oxidation in necrotizing pancreatitis in rats and its modulation by oxypurinol and pentoxifylline; (2) to determine whether TNF-α is responsible for glutathione depletion in acute pancreatitis; and (3) to elucidate the role of oxidative stress in the inflammatory cascade in pancreatic AR42J acinar cells. We report here that oxidative stress and nitrosative stress occur in pancreas and lung in acute pancreatitis and the co-treatment with oxypurinol and pentoxifylline prevents oxidative stress in both tissues. Oxypurinol was effective in preventing glutathione oxidation, whereas pentoxifylline abrogated glutathione depletion. This latter effect was independent of TNF-α since glutathione depletion occurred in mice deficient in TNF-α or its receptors after induction of pancreatitis. The beneficial effects of oxypurinol in the inflammatory response may also be ascribed to a partial inhibition of MEK1/2 activity. Pentoxifylline markedly reduced the expression of Icam1 and iNos induced by TNF-α in vitro in AR42J cells. Oxidative stress significantly contributes to the TNF-α-induced up-regulation of Icam and iNos in AR42J cells. These results provide new insights into the mechanism of action of oxypurinol and pentoxifylline as anti-inflammatory agents in acute pancreatitis.

Stat3 and MMP7 contribute to pancreatic ductal adenocarcinoma initiation and progression

Chronic pancreatitis is a well-known risk factor for pancreatic ductal adenocarcinoma (PDA) development in humans, and inflammation promotes PDA initiation and progression in mouse models of the disease. However, the mechanistic link between inflammatory damage and PDA initiation is unclear. Using a Kras-driven mouse model of PDA, we establish that the inflammatory mediator Stat3 is a critical component of spontaneous and pancreatitis-accelerated PDA precursor formation and supports cell proliferation, metaplasia-associated inflammation, and MMP7 expression during neoplastic development. Furthermore, we show that Stat3 signaling enforces MMP7 expression in PDA cells and that MMP7 deletion limits tumor size and metastasis in mice. Finally, we demonstrate that serum MMP7 level in human patients with PDA correlated with metastatic disease and survival.

PKC δ mediates pro-inflammatory responses in a mouse model of caerulein-induced acute pancreatitis

Acute pancreatitis is an inflammatory disorder of the pancreas. Protein kinase C (PKC) δ plays an important role in mediating chemokine production in mouse pancreatic acinar cells. This study aims to investigate the role of PKC δ in the pathogenesis of acute pancreatitis and to explore the mechanisms through which PKC δ mediates pro-inflammatory signaling. Acute pancreatitis was induced in mice by ten hourly intraperitoneal injections of caerulein. PKC δ translocation inhibitor peptide (δV1-1) at a dose of 1.0 mg/kg or Tat (carrier peptide) at a dose of 1.0 mg/kg was administered to mice either 1 h before or 1 h after the first caerulein injection. One hour after the last caerulein injection, the mice were killed and pancreas, lungs, and blood were collected. Prophylactic and therapeutic treatment with δV1-1 attenuated caerulein-induced plasma amylase levels and pancreatic edema. Treatment with δV1-1 decreased myeloperoxidase activity and monocyte chemotactic protein-1 levels in both pancreas and plasma. PKC δ mediated acute pancreatitis by activating pancreatic nuclear factor κB, activator protein-1, and mitogen-activated protein kinases. Moreover, blockade of PKC δ attenuated lung myeloperoxidase activity and edema. Histological examination of pancreatic and lung sections confirmed protection against acute pancreatitis. Treatment with Tat had no protective effect on acute pancreatitis. Blockade of PKC δ represents a promising prophylactic and/or therapeutic tool for the treatment of acute pancreatitis.

Transcriptional regulation of CXC-ELR chemokines KC and MIP-2 in mouse pancreatic acini

Neutrophils and their chemoattractants, the CXC-ELR chemokines keratinocyte cytokine (KC) and macrophage inflammatory protein-2 (MIP-2), play a critical role in pancreatitis. While acute pancreatitis is initiated in acinar cells, it is unclear if these are a source of CXC-ELR chemokines. KC and MIP-2 have NF-κB, activator protein-1 (AP-1) sites in their promoter regions. However, previous studies have shown increased basal and reduced caerulein-induced AP-1 activation in harvested pancreatic tissue in vitro, which limits interpreting the caerulein-induced response. Moreover, recent studies suggest that NF-κB silencing in acinar cells alone may not be sufficient to reduce inflammation in acute pancreatitis. Thus the aim of this study was to determine whether acinar cells are a source of KC and MIP-2 and to understand their transcriptional regulation. Primary overnight-cultured murine pancreatic acini were used after confirming their ability to replicate physiological and pathological acinar cell responses. Upstream signaling resulting in KC, MIP-2 upregulation was studied along with activation of the transcription factors NF-κB and AP-1. Cultured acini replicated critical responses to physiological and pathological caerulein concentrations. KC and MIP-2 mRNA levels increased in response to supramaximal but not to physiological caerulein doses. This upregulation was calcium and protein kinase C (PKC), but not cAMP, dependent. NF-κB inhibition completely prevented upregulation of KC but not MIP-2. Complete suppression of MIP-2 upregulation required dual inhibition of NF-κB and AP-1. Acinar cells are a likely source of KC and MIP-2 upregulation during pancreatitis. This upregulation is dependent on calcium and PKC. MIP-2 upregulation requires both NF-κB and AP-1 in these cells. Thus dual inhibition of NF-κB and AP-1 may be a more successful strategy to reduce inflammation in pancreatitis than targeting NF-κB alone.

Proposed protective mechanism of the pancreas in the rat

Background

Heparan sulphate is known to have various functions in the animal body, including surveillance of tissue integrity. Administered intraperitoneally, it induces a systemic inflammatory response syndrome and when given locally in the pancreas it initiates a protective inflammatory response. The aim of the present study was to investigate the underlying mechanisms behind cell recruitment following intra-ductal infusion of heparan sulphate.

Methods

Rats were subjected to intraductal-infusion of heparan sulphate, lipopolysaccharide and phosphate buffered saline into the pancreas. Pancreatic tissue was harvested 1, 3, 6, 9 or 48 hours after infusion and stained immunohistochemically for myeloperoxidase, ED-1, CINC-1 and MCP-1, as well as using eosin hematoxylin staining. Furthermore, MPO activity and MCP-1 and CINC-1 concentrations of tissue homogenates were measured. All differences were analyzed statistically using the Mann-Whitney U-test.

Results

During HS infusion, a rapid influx of macrophages/monocytes, as visualized as ED-1 positive cells, was seen reaching a maximum at 6 hours. After 48 hours, the same levels of ED-1 positive cells were noted in the pancreatic tissue, but with different location and morphology. Increased neutrophil numbers of heparan sulphate treated animals compared to control could be detected only 9 hours after infusion. The number of neutrophils was lower than the number of ED-1 positive cells. On the contrary, LPS infusion caused increased neutrophil numbers to a larger extent than heparan sulphate. Furthermore, this accumulation of neutrophils preceded the infiltration of ED-1 positive cells. Chemokine expression correlates very well to the cell infiltrate. MCP-1 was evident in the ductal cells of both groups early on. MCP-1 preceded monocyte infiltration in both groups, while the CINC-1 increase was only noticeable in the LPS group.

Conclusions

Our data suggest that heparan and LPS both induce host defense reactions, though by using different mechanisms of cell-recruitment. This implies that the etiology of pancreatic inflammation may influence how the subsequent events will develop.

Inflammatory role of the acinar cells during acute pancreatitis

Pancreatic acinar cells are secretory cells whose main function is to synthesize, store and finally release digestive enzymes into the duodenum. However, in response to noxious stimuli, acinar cells behave like real inflammatory cells because of their ability to activate signalling transduction pathways involved in the expression of inflammatory mediators. Mediated by the kinase cascade, activation of Nuclear factor-κB, Activating factor-1 and Signal transducers and activators of transcription transcription factors has been demonstrated in acinar cells, resulting in overexpression of inflammatory genes. In turn, kinase activity is down-regulated by protein phosphatases and the final balance between kinase and phosphatase activity will determine the capability of the acinar cells to produce inflammatory factors. The kinase/phosphatase pair is a redox-sensitive system in which kinase activation overwhelms phosphatase activity under oxidant conditions. Thus, the oxidative stress developed within acinar cells at early stages of acute pancreatitis triggers the activation of signalling pathways involved in the up-regulation of cytokines, chemokines and adhesion molecules. In this way, acinar cells trigger the release of the first inflammatory signals which can mediate the activation and recruitment of circulating inflammatory cells into the injured pancreas. Accordingly, the role of acinar cells as promoters of the inflammatory response in acute pancreatitis may be considered. This concept leads to amplifying the focus from leukocyte to acinar cells themselves, to explain the local inflammation in early pancreatitis.

Connections between genetics and clinical data: Role of MCP-1, CFTR, and SPINK-1 in the setting of acute, acute recurrent, and chronic pancreatitis

OBJECTIVES

Acute, acute recurrent, and chronic pancreatitis are inflammatory diseases with multifactorial pathogenic mechanisms. Genetic mutations and polymorphisms have been correlated with pancreatitis. The aim of this study was to investigate the association of cystic fibrosis transmembrane conductance regulator (CFTR) and serine protease inhibitor Kazal type 1 (SPINK-1) gene mutations and monocyte chemoattractant protein 1 (MCP-1) -2518A/G polymorphism with acute pancreatitis (AP), acute recurrent pancreatitis (ARP), and chronic pancreatitis (CP), and to associate genetic backgrounds with clinical phenotype in these three conditions.

METHODS

One hundred eighteen AP, 64 ARP, 142 CP patients, and 88 normal controls were enrolled consecutively. We analyzed MCP-1 serum levels using enzyme-linked immunosorbent assay. Polymorphism -2518 of MCP-1 and SPINK-1 N34S gene mutations were determined by PCR-restriction-fragment length polymorphism. Sequence analysis was performed when necessary. Thirty-three CFTR mutations were analyzed in CP and ARP patients using multiplex DNA testing.

RESULTS

Serum MCP-1 levels were significantly higher in all patients affected by pancreatic inflammatory diseases. Moreover, we found a significant over-representation of the MCP-1G allele in ARP patients. We found a statistically significant association of CFTR gene mutations with ARP, but not with CP. We did not find a statistically significant association of ARP or CP with the N34S SPINK-1 gene mutation. Interestingly, 39 of 64 ARP patients (61%) carried at least one genetic mutation and/or polymorphism. Five of 64 ARP patients had pancreas divisum and four of these five also carried the G allele.

CONCLUSIONS

Analysis of a comprehensive range of potential susceptibility variants is needed to support modeling of the effects of genes and environment in pancreatitis. As such, beyond gene mutations, the context within which those mutations exist must be considered. In pancreatitis the context includes the inflammatory response, clinical features, and exogenous factors.

Mechanisms of dexamethasone-mediated chemokine down-regulation in mild and severe acute pancreatitis

This study aimed to investigate the role of therapeutic dexamethasone (Dex) treatment on the mechanisms underlying chemokine expression during mild and severe acute pancreatitis (AP) experimentally induced in rats. Regardless of the AP severity, Dex (1 mg/kg), administered 1 h after AP, reduced the acinar cell activation of extracellular signal-regulated kinase (ERK) and c-Jun-NH(2)-terminal kinase (JNK) but failed to reduce p38-mitogen-activated protein kinase (MAPK) in severe AP. In both AP models, Dex inhibited the activation of nuclear factor-kappaB (NF-kappaB) and signal transducers and activators of transcription (STAT) factors. All of this resulted in pancreatic down-regulation of the chemokines monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC). Lower plasma chemokine levels as well as decreased amylasemia, hematocrit and plasma interleukin-1beta (Il-1beta) levels were found either in mild or severe AP treated with Dex. Pancreatic neutrophil infiltration was attenuated by Dex in mild but not in severe AP. In conclusion, by targeting MAPKs, NF-kappaB and STAT3 pathways, Dex treatment down-regulated the chemokine expression in different cell sources during mild and severe AP, resulting in decreased severity of the disease.

The beneficial effects of pentoxifylline on caerulein-induced acute pancreatitis in rats

In this study we aimed to investigate the effect of pentoxifylline on caerulein-induced acute pancreatitis (AP) by detecting oxidative stress markers and performing histopathological examination. Twenty-one adult female Sprague-Dawley rats were divided into three groups as follows: control, caerulein, and caerulein + pentoxifylline groups. Pancreatic tissues of rats from all groups were removed for light and electron microscopic examination and determination of oxidative stress markers. Pancreatic oxidative stress markers were evaluated by the measurements of malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and total glutathione (GSH). Serum amylase and lipase levels were determined spectrophotometrically. The pancreatic damage score was significantly increased (P < 0.005) in the caerulein group, whereas it was decreased (P < 0.05) in the caerulein+ with pentoxifylline group. MDA levels, CAT, SOD, GPx, and GSH activities were significantly altered (P < 0.05, P < 0.005) in the caerulein group and indicated increased oxidative stress. Oxidative stress markers were normalized with pentoxifylline administration. Caerulein administration resulted in significant increase (P < 0.05) in amylase and lipase levels; pentoxifylline reduced the levels of these enzymes. Pentoxifylline is potentially capable of limiting pancreatic damage produced during AP by restoring the fine structure of acinar cells and tissue antioxidant enzyme activities. We concluded that pentoxifylline may have beneficial effects in the treatment of caerulein-induced AP.

Involvement of SRC family kinases in substance P-induced chemokine production in mouse pancreatic acinar cells and its significance in acute pancreatitis

Substance P is known to play a key role in the pathogenesis of acute pancreatitis. Src family kinases (SFKs) are known to be involved in cytokine signaling. However, the involvement of SFKs in substance P-induced chemokine production and its role in acute pancreatitis have not been investigated yet. To that end, we have used primary preparations of mouse pancreatic acinar cells as our model to show that substance P/neurokinin 1 receptor (NK1R) induced activation of SFKs. SFKs mediated the activation of mitogen-activated protein kinases [extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK)], transcription factors [signal transducer and activator of transcription (STAT) 3, nuclear factor (NF) kappaB, activator protein-1 (AP-1)], and production of chemokines in pancreatic acinar cells. We further tested the significance of the SFK signaling pathway in acute pancreatitis. Our results show, for the first time, that treatment of mice with the potent and selective SFK inhibitor PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4-D] pyrimidine], but not its negative inhibitor PP3 (4-amino-7-phenylpyrazol [3,4-D] pyrimidine), reduced the severity of pancreatitis. This was proven by significant attenuation of hyperamylasemia, pancreatic myeloperoxidase activity, chemokines, and water content. Histological evidence of diminished pancreatic injury also confirmed the protective effect of the inhibition of SFKs. Moreover, treatment with the substance P receptor antagonist CP96345 [(2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)-methyl)-1-azabicyclo(2.2.2.)-octan-3-amine] attenuated acute pancreatitis-induced activation of SFKs, ERK, JNK, STAT3, NFkappaB, and AP-1. The proposed signaling pathway through which substance P mediates acute pancreatitis is through substance P/NK1R-SFKs-(ERK, JNK)-(STAT3, NFkappaB, AP-1) chemokines. In light of our study, we propose that drugs targeting the substance P-mediated signaling pathways could prove beneficial in improving treatment efficacy in acute pancreatitis.

Role of oxidative stress in pancreatic inflammation

Reactive oxygen and reactive nitrogen species (ROS/RNS) have been implicated in the pathogenesis of acute and chronic pancreatitis. Clinical and basic science studies have indicated that ROS/RNS formation processes are intimately linked to the development of the inflammatory disorders. The detrimental effects of highly reactive ROS/RNS are mediated by their direct actions on biomolecules (lipids, proteins, and nucleic acids) and activation of proinflammatory signal cascades, which subsequently lead to activation of immune responses. The present article summarizes the possible sources of ROS/RNS formation and the detailed signaling cascades implicated in the pathogenesis of pancreatic inflammation, as observed in acute and chronic pancreatitis. A therapeutic ROS/RNS-scavenging strategy has been advocated for decades; however, clinical studies examining such approaches have been inconsistent in their results. Emerging evidence indicates that pancreatitis-inducing ROS/RNS generation may be attenuated by targeting ROS/RNS-generating enzymes and upstream mediators.

The role of redox status on chemokine expression in acute pancreatitis

This study focused on the involvement of oxidative stress in the mechanisms mediating chemokine production in different cell sources during mild and severe acute pancreatitis (AP) induced by bile-pancreatic duct obstruction (BPDO) and 3.5% NaTc, respectively. N-Acetylcysteine (NAC) was used as antioxidant treatment. Pancreatic glutathione depletion, acinar overexpression of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC), and activation of p38MAPK, NF-kappaB and STAT3 were found in both AP models. NAC reduced the depletion of glutathione in BPDO- but not in NaTc-induced AP, in which oxidative stress overwhelmed the antioxidant capability of NAC. As a result, inhibition of the acinar chemokine expression and signalling pathways occurs in mild, but not in severe AP. However, MCP-1 and CINC expressions in whole pancreas and plasma chemokine levels were not reduced by NAC, even in BPDO-induced AP, suggesting that in addition to acini, other pancreatic cells produced chemokines by antioxidant resistant mechanisms. The high Il-6 plasma levels found during AP, both in NAC-treated and non-treated rats, pointed out cytokines as activating factors of chemokine expression in non-acinar cells. In conclusion, from early AP oxidant-mediated MAPK, NF-kappaB and STAT3 activation triggers the chemokine expression in acini but not in non-acinar cells.

Protease activation, pancreatic leakage, and inflammation in acute pancreatitis: differences between mild and severe cases and changes over the first three days

BACKGROUND/AIMS

The pathophysiology of acute pancreatitis (AP) may be studied using markers of protease activation (active carboxypeptidase B (aCAP), the activation peptide of carboxypeptidase B (CAPAP)), leakage of pancreatic enzymes (trypsinogen-2, procarboxypeptidase B (proCAP), amylase), and inflammation (monocyte chemoattractant protein-1 (MCP-1), CRP).

METHODS

This prospective study included 140 cases of AP. Mild (n = 124) and severe (n = 16) cases were compared with respect to serum levels of trypsinogen-2, proCAP, amylase, aCAP, CAPAP (serum/urine), MCP-1 (serum/urine) and CRP on days 1, 2 and 3 from onset of symptoms. All patients with information on all 3 days were included in a time-course analysis (n = 44-55, except amylase: n = 27).

RESULTS

High levels in severe versus mild cases were seen for trypsinogen-2, CAPAP in serum and urine, and MCP-1 in serum on days 1-3. No differences were seen for proCAP, amylase and aCAP. MCP-1 in urine was significantly elevated on day 1-2, and CRP on day 2-3. CAPAP and MCP-1 levels peaked early and stayed elevated for 48 h in serum.

CONCLUSION

Protease activation and inflammation are early events in AP, with high levels of these markers within 24 h. Protease activation declines after 48 h, whereas inflammation is present for a longer time.

Primary culture of pancreatic (human) acinar cells

The acinar cell culture plays a very important role in research of pancreatic pathophysiology. The aim of this study was to establish a long-term culture of human (foetal) pancreatic acinar cells in standardized nutrient media with supplements. Acinar cells were prepared from pancreatic tissues obtained from aborted foetus (> or =35 weeks) with no prior pancreatic complications by collagenase digestion and cultured using different media and supplements. The purity and phenotype of acinar cells was confirmed by various staining techniques and FACS. The acinar cell proliferation was determined at different time intervals by Bromo-deoxyuridine (BrdU) incorporation, and metabolic enzyme activity was analysed. The acini could be cultured and maintained in Ham's F-12 K/M199 media in the presence of 5% BSA, 0.1 mg/ml STI, 10 ng/ml EGF, and 10% FCS with the same morphological appearance as that of freshly prepared for 12 days with maximum viability of 80-85% and formation of monolayer without extracellular matrix. A significant BrdU incorporation of acinar cells in primary culture was observed which was maximum (105%) at day four. Higher amylase and lipase activity was seen in freshly isolated acinar cells which decreased with time of the culture. The established human pancreatic acinar cell culture may act as an excellent model to study exocrine dysfunction or pancreatitis in response to acinar cell injury.

Role of calcium in substance P-induced chemokine synthesis in mouse pancreatic acinar cells

BACKGROUND AND PURPOSE

Substance P (SP) and chemokines play critical roles in acute pancreatitis. SP elevates cytosolic calcium in pancreatic acinar cells and elevated cytosolic calcium is thought to be an early event in the pathogenesis of acute pancreatitis. SP induces production of chemokines MCP-1, MIP-1alpha and MIP-2 in pancreatic acinar cells, however the exact mechanism by which SP stimulates the production of these pro-inflammatory mediators remain undetermined. The aim of the present study is to investigate the role of calcium in SP-induced chemokine production in pancreatic acinar cells and to establish the signal transduction mechanisms involved.

EXPERIMENTAL APPROACH

An in vitro model of isolated mouse pancreatic acinar cells was used. Western blotting analysis, ELISA and calcium measurement were performed.

KEY RESULTS

SP increased chemokine secretion through the activation of PKCalpha/betaII, MAPKinases (ERK and JNK), NFkappaB and AP-1 in pancreatic acinar cells. These effects were blocked by pretreatment of the cells with the specific calcium chelator BAPTA-AM. Moreover, SP-induced activation of PKCalpha/betaII, ERK, JNK, NF-kappaB, AP-1 and chemokine production was inhibited by the specific phospholipase C inhibitor U73122.

CONCLUSIONS AND IMPLICATIONS

SP-induced chemokine production in pancreatic acinar cells resulted from PLC-induced elevated intracellular calcium and PKCalpha/betaII activation, subsequently leading to the activation of MAPKinases (ERK and JNK) and transcription factors NF-kappaB and AP-1. The present study demonstrates the critical role of calcium in SP-induced chemokine production in pancreatic acinar cells. Drugs targeting the SP-calcium mediated signaling pathways could prove beneficial in improving the treatment of acute pancreatitis.

Effect of mitogen-activated protein kinases on chemokine synthesis induced by substance P in mouse pancreatic acinar cells

Substance P, acting via its neurokinin 1 receptor (NK1 R), plays an important role in mediating a variety of inflammatory processes. Its interaction with chemokines is known to play a crucial role in the pathogenesis of acute pancreatitis. In pancreatic acinar cells, substance P stimulates the release of NFκB-driven chemokines. However, the signal transduction pathways by which substance P-NK1 R interaction induces chemokine production are still unclear. To that end, we went on to examine the participation of mitogen-activated protein kinases (MAPKs) in substance P-induced synthesis of pro-inflammatory chemokines, monocyte chemoanractant protein-1 (MCP-I), macrophage inflammatory protein-lα (MIP-lα) and macrophage inflammatory protein-2 (MIP-2), in pancreatic acini. In this study, we observed a time-dependent activation of ERK1/2, c-Jun N-terminal kinase (JNK), NFκB and activator protein-1 (AP-1) when pancreatic acini were stimulated with substance P. Moreover, substance P-induced ERK 1/2, JNK, NFκB and AP-1 activation as well as chemokine synthesis were blocked by pre-treatment with either extracellular signal-regulated protein kinase kinase 1 (MEK1) inhibitor or JNK inhibitor. In addition, substance P-induced activation of ERK 112, JNK, NFκB and AP-1-driven chemokine production were attenuated by CP96345, a selective NK1 R antagonist, in pancreatic acinar cells. Taken together, these results suggest that substance P-NK1 R induced chemokine production depends on the activation of MAPKs-mediated NFκB and AP-1 signalling pathways in mouse pancreatic acini.

Blocking of monocyte chemoattractant protein-1 (MCP-1) activity attenuates the severity of acute pancreatitis in rats

BACKGROUND

Monocyte chemoattractant protein-1 (MCP-1) has been shown to affect the progression of various inflammatory disorders, including pancreatitis. To investigate the role of MCP-1 in acute pancreatitis and to seek possible therapeutic means, we evaluated the effect of a plasmid expression vector containing a dominant-negative mutant MCP-1 gene (mMCP-1).

METHODS

Two rat models of acute pancreatitis were employed that used either cerulein (for mild pancreatitis) or a mixture of 5% taurocholic acid and trypsin (for severe pancreatitis). At 6 h after induction of acute pancreatitis with or without injection of mMCP-1, serum amylase levels and cytokine levels, as well as morphological evaluation of the pancreas, were determined. Survival rates were also evaluated.

RESULTS

Severe pancreatitis was significantly reduced by mMCP-1 injection. mMCP-1 decreased serum levels of amylase, IL-6, IL-10, and LDH, and improved the survival rate 48 h after disease onset. Histopathological changes of pancreas and lungs were also improved by mMCP-1.

CONCLUSIONS

MCP-1 appears to be involved in the progression of severe forms of acute pancreatitis. Our data suggested that MCP-1 is a candidate as a therapeutic target to treat acute pancreatitis.

Inhibition of hydrogen sulfide synthesis attenuates chemokine production and protects mice against acute pancreatitis and associated lung injury

OBJECTIVES

The present study investigated whether chemokines are involved in hydrogen sulfide (H2S)-associated pathogenesis of acute pancreatitis and associated lung injury.

METHODS

We have examined the effect of DL-propargylglycine, a cystathionine gamma-lyase inhibitor, on the synthesis of CC chemokine monocyte chemotactic protein 1, Regulated upon Activation, Normal T-cell Expressed, and Secreted, and macrophage inflammatory protein-1alpha (MIP-1alpha), and CXC chemokine MIP-2 in an in vitro and in vivo model of cerulein-induced acute pancreatitis and associated lung injury. In addition, the pancreatic acinar cells were treated with H2S donor drug, sodium hydrosulfide. The expression of these chemokines in the pancreatic acini, pancreas, and lungs was determined by quantitative real-time reverse transcriptase polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry.

RESULTS

After treatment with DL-propargylglycine, reverse transcriptase polymerase chain reaction, and enzyme-linked immunosorbent assay demonstrated down-regulation of cerulein-induced increase in monocyte chemotactic protein 1, MIP-1alpha, and MIP-2 expression but had no apparent effect on Regulated upon Activation, Normal T-cell Expressed, and Secreted expression.

CONCLUSIONS

These results suggest that the proinflammatory effect of H2S may be mediated by chemokines.

Overexpression ofErbB2 in the exocrine pancreas induces an inflammatory response but not increased proliferation

Tyrosine kinase receptors such as members of the epidermal growth factor receptor family and their respective ligands are frequently overexpressed in pancreatic cancer as well as in chronic pancreatitis. In this study, the role of ErbB2 in the exocrine pancreas was examined by ectopic overexpression under the control of the proximal rat elastase promoter. Three independent transgenic mouse lines overexpressing ErbB2 were established by pronuclear injection. Pancreatic mRNA and protein levels were analyzed by real time PCR, immunohistochemistry and immunoblot analysis, RAS activity by using a specific immunoprecipitation assay and various kinase activities by phosphospecific antibodies. Overexpression of ErbB2 in the exocrine pancreas resulted in increased RAS activity and downstream activation of ERK1/2, but not in transgenic increased proliferation of acinar and ductal cells. At later timepoints, some mice showed focal areas of acinar cell damage with upregulated mRNA levels for Cyclin D1 and p16(INK4a). Despite the increased mRNA level, cyclin D1 protein levels were downregulated. We observed areas of focal infiltrations with inflammatory cells interspersed in the exocrine pancreas. NF-kappaB activity was induced in transgenic acinar cells compared with controls contributing to high levels of chemokine and cytokine gene expression such as CCR-1 and CCL3. These data suggest that overexpression of ErbB2 in acinar cells leads to increased RAS activity without cell cycle progression and mediates inflammation via NF-kappaB. We conclude that the biological response of ErbB2/RAS signaling depends highly on cellular context.

Acute pancreatitis: models, markers, and mediators

Acute pancreatitis has an incidence of approximately 40 cases per year per 100,000 adults. Although usually self-limiting, 10% to 20% of afflicted patients will progress to severe pancreatitis. The mortality rate among patients with severe pancreatitis may approach 30% when they progress to multisystem organ failure. The development of acute pancreatitis illustrates the requirement for understanding the basic mechanisms of disease progression to drive the exploration of therapeutic options. The pathogenesis of acute pancreatitis involves the interplay of local and systemic immune responses that are often difficult to characterize, particularly when results from animal models are used as a foundation for human trials. Experimental studies suggest that the prognosis for acute pancreatitis depends upon the degree of pancreatic necrosis and the intensity of multisystem organ failure generated by the systemic inflammatory response. This suggests an intricate balance between localized tissue damage with proinflammatory cytokine production and a systemic, anti-inflammatory response that restricts the inappropriate movement of proinflammatory agents into the circulation. The critical players of this interaction include the proinflammatory cytokines IL-1beta, TNF-alpha, IL-6, IL-8, and platelet activating factor (PAF). The anti-inflammatory cytokines IL-10, as well as TNF-soluble receptors and IL-1 receptor antagonist, have also been shown to be intimately involved in the inflammatory response to acute pancreatitis. Other compounds implicated in disease pathogenesis in experimental models include complement, bradykinin, nitric oxide, reactive oxygen intermediates, substance P, and higher polyamines. Several of these mediators have been documented to be present at increased concentrations in the plasma of patients with severe, acute pancreatitis. Preclinical work has shown that some of these mediators are markers for disease activity, whereas other inflammatory components may actually drive the disease process as important mediators. Implication of such mediators suggests that interruption or blunting of an inappropriate immune response has the potential to improve outcome. Although the manipulations of specific mediators in animal models may be promising, they may not transition well to the human clinical setting. However, continued reliance on experimental animal models of acute pancreatitis may be necessary to determine the underlying causes of disease. Full understanding of these basic mechanisms involves determining not only which mediators are present, but also closely documenting the kinetics of their appearance. Measurement of the inflammatory response may also serve to identify diagnostic markers for the presence of acute pancreatitis and provide insight into prognosis. Understanding the models, documenting the markers, and deciphering the mediators have the potential to improve treatment of acute pancreatitis.

Overexpression of redox-active protein thioredoxin-1 prevents development of chronic pancreatitis in mice

Chronic pancreatitis (CP) is considered to result from repetitive pancreatic injury, and sustained production of various proinflammatory cytokines and chemokines are closely involved in its pathogenesis. Monocyte chemoattractant protein 1 (MCP-1), a member of the CC chemokine family, is believed to contribute to the progression of CP through monocyte/macrophage recruitment. This study aimed to clarify the protective role of thioredoxin-1 (TRX-1), a redox-regulating protein with antioxidative activity, in MCP-1 production and pancreatic fibrosis using a CP model in transgenic mice overexpressing TRX-1 (TRX-1-TG mice) and wildtype C57BL/6 mice. Experimental CP was induced by repeated administration of cerulein and lipopolysaccharide for 6 weeks. In TRX-1-TG mice, pancreatic atrophy was ameliorated, and histologically detectable inflammatory cell infiltration, glandular atrophy, and pseudotubular complex formation were suppressed. Overexpression of TRX-1 also attenuated pancreatic fibrosis and suppressed the activation of pancreatic stellate cells. Serum levels of MCP-1 and pancreatic expression of transforming growth factor-beta, platelet-derived growth factor, and MCP-1 were reduced in TRX-1-TG mice compared with levels in wild-type mice. Overexpression of TRX-1 also reduced H(2)O(2)-induced MCP-1 production in isolated pancreatic acinar cells. These results indicate that TRX-1 can potentially attenuate pancreatic fibrosis via the suppression of oxidative stress and MCP-1-mediated chronic inflammation.

Mechanisms of acinar cell injury in acute pancreatitis

Acute pancreatitis has many causes, all leading to a common pathway of changes within the pancreatic acinar cell. Key amongst these changes is premature intracellular activation of digestive enzymes but this is also accompanied by the appearance of cytosolic vacuoles, co-localization of digestive and lysosomal enzymes, activation of NF-kappaB, and release of pro-inflammatory cytokines. The exact mechanism responsible for enzyme activation remains the subject of much research effort and not a little debate, however it is clear that all of these changes are triggered by an abnormal, sustained rise in cytosolic calcium concentration, which is itself dependent both on release of calcium from endoplasmic reticulum stores and uptake from the extracellular milieu. Activated enzymes are directly damaging to the acinar cell themselves, but recruitment of circulating neutrophils leads to further cellular damage. Cytokines and neutrophil activation are also responsible for the systemic inflammatory response typically seen in severe acute pancreatitis.

Inflammatory response on the pancreatic acinar cell injury

Acute pancreatitis is an inflammatory disorder, and inflammation not only affects the pathogenesis but also the course of the disease. Acinar cell injury early in acute pancreatitis leads to a local inflammatory reaction; if marked this leads to a systemic inflammatory response syndrome (SIRS). An excessive SIRS leads to distant organ damage and multiple organ dysfunction syndrome (MODS). MODS associated with acute pancreatitis is the primary cause of morbidity and mortality in this condition. Recent studies by us and other investigators have established the critical role played by inflammatory mediators such as TNF-alpha, IL-1beta, IL-6, IL-8, CINC/GRO-alpha, MCP-1, PAF, IL-10, CD40L, C5a, ICAM-1, MIP1-alpha, RANTES, substance P, and hydrogen sulfide in acute pancreatitis and the resultant MODS. This review intends to present an overview of the inflammatory response that takes place following pancreatic acinar cell injury.

Proinflammatory role of trypsin and protease-activated receptor-2 in a rat model of acute pancreatitis

OBJECTIVES

The pathophysiology of acute pancreatitis is strongly associated with autoactivation of trypsin. The biologic activity of trypsin on cells is attributed to the activation of protease-activated receptor-2 (PAR-2). We hypothesize that trypsin may activate acinar cells or inflammatory cells through PAR-2 signals in acute pancreatitis.

METHODS

We immunochemically analyzed the expression of PAR-2 in the rat acinar cell line, ARIP, and the rat pancreas, using anti-rat PAR-2 cleavage site (PCS) and anti-rat PAR-2 N-terminal fragment (PNF) antibodies. Plasma levels of PNF were determined. Furthermore, the effects of the anti-rat PCS antibody and nafamostat mesylate, a potent trypsin inhibitor, on PAR-2 activation during acute pancreatitis were also analyzed.

RESULTS

ARIP cells expressed PAR-2, which was activated by exogenous trypsin activity. We also showed that PAR-2 is strongly expressed in pancreatic acinar and duct cells and that it is activated in rat cerulein-induced acute pancreatitis. The anti-rat PCS antibody and nafamostat mesylate reduced interleukin-6 and interferon gamma production and alleviated distant organ injury.

CONCLUSIONS

These results suggest that trypsin and its specific receptor, PAR-2, play an important role in cytokine production and the resultant development of distant organ injury during rat acute pancreatitis.

Pathophysiology of acute pancreatitis

Acute pancreatitis is a common clinical condition. It is a disease of variable severity in which some patients experience mild, self-limited attacks while others manifest a severe, highly morbid, and frequently lethal attack. The exact mechanisms by which diverse etiological factors induce an attack are still unclear. It is generally believed that the earliest events in acute pancreatitis occur within acinar cells. Acinar cell injury early in acute pancreatitis leads to a local inflammatory reaction. If this inflammatory reaction is marked, it leads to a systemic inflammatory response syndrome (SIRS). An excessive SIRS leads to distant organ damage and multiple organ dysfunction syndrome (MODS). MODS associated with acute pancreatitis is the primary cause of morbidity and mortality in this condition. Recent studies have established the role played by inflammatory mediators in the pathogenesis of acute pancreatitis and the resultant MODS. At the same time, recent research has demonstrated the importance of acinar cell death in the form of apoptosis and necrosis as a determinant of pancreatitis severity. In this review, we will discuss about our current understanding of the pathophysiology of acute pancreatitis.

Biliary pancreatitis-associated ascitic fluid activates the production of tumor necrosis factor-alpha in acinar cells

OBJECTIVE

Acute pancreatitis is associated with increased cytokine release from different cell sources. We have investigated the ability of acinar cells, in comparison with inflammatory peripheral blood cells, to produce tumor necrosis factor (TNF)-alpha in response to pancreatitis-associated ascitic fluid (PAAF).

DESIGN

Controlled, randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Male Wistar rats.

INTERVENTIONS

Flow cytometry using phycoerythrin-labeled monoclonal anti-TNF-alpha antiserum.

MEASUREMENTS AND MAIN RESULTS

PAAF (20%, v:v) obtained from rats with acute pancreatitis induced by bile-pancreatic duct obstruction significantly increased TNF-alpha production in acinar cells, as measured by flow cytometry using phycoerythrin-labeled monoclonal anti-TNF-alpha antiserum. Neither heating of PAAF nor the addition of soybean trypsin inhibitor or neutralizing amounts of anti-TNF-alpha monoclonal antiserum reduced the acinar cell TNF-alpha production. Monocytes and lymphocytes did not produce TNF-alpha in response to PAAF. Likewise, the typical monocyte and lymphocyte stimulating factors-lipopolysaccharide (10 microg/microL) and phorbol 12-myristate 13-acetate (250 ng/mL) plus ionomycin (1 microg/mL), respectively-were not able to produce TNF-alpha in acinar cells. By comparison of the two acinar cell populations differentiated by flow cytometry, R2 cells (with higher forward scatter values) showed a greater ability to produce TNF-alpha in response to PAAF than R1 cells. Acinar cell nuclear factor-kappaB was activated, but TNF-alpha production was not totally inhibited in presence of N-acetyl cysteine (30, 100 mM).

CONCLUSIONS

The production of TNF-alpha from different cell sources is selectively activated. PAAF may be involved in the pathophysiology of acute pancreatitis by TNF-alpha production in acinar cells through mechanisms partially mediated by nuclear factor-kappaB activation. PAAF components, such as TNF-alpha or trypsin, are not responsible for acinar cell activation. TNF-alpha was induced by heat-resistant PAAF factors, displaying acinar cells with higher forward scatter (R2) a greater ability to increase the TNF-alpha production than R1 cells.

Apoptosis of pancreatic acinar cells in acute pancreatitis: is it good or bad?

Acute pancreatitis is a disease of variable severity in which some patients experience mild, self-limited attacks while others manifest a severe, highly morbid, and frequently lethal attack. The events that regulate the severity of acute pancreatitis are, for the most part, unknown. Several recent studies have suggested that the acinar cell response to injury may be an important determinant of disease severity. In these studies, mild acute pancreatitis was found to be associated with extensive apoptotic acinar cell death while severe acute pancreatitis was found to involve extensive acinar cell necrosis but very little acinar cell apoptosis. These observations have led to the hypothesis that apoptosis might be a favorable response to acinar cell and that interventions which favor induction of apoptotic, as opposed to necrotic, acinar cell death might reduce the severity of an attack of acute pancreatitis. This review aims to discuss our current understanding of the contribution of acinar cell apoptosis to the severity of acute pancreatitis.

Acute pancreatitis and organ failure: pathophysiology, natural history, and management strategies

Acute pancreatitis is a common condition that carries a significant risk of morbidity and mortality. It is characterized by intra-acinar cell activation of digestive enzymes and a subsequent systemic inflammatory response governed by the release of proinflammatory cytokines. In 80% of patients the disease runs a self-limiting course, but in the rest, pancreatic necrosis and systemic organ failure carry a mortality rate of up to 40%. The key to management is early identification of the patients liable to have a severe attack and require treatment in a high-dependency or critical-care setting by a specialist team. In gallstone-induced pancreatitis, early removal of ductal calculi by endoscopic sphincterotomy is indicated. The use of prophylactic antibiotics to prevent the infection of pancreatic necrosis remains controversial, but once established, infected necrosis must be removed. Although a number of techniques to accomplish this end have been described, minimally invasive techniques are gaining in popularity.