Review of experimental animal models of biliary acute pancreatitis and recent advances in basic research

Resveratrol in animal models of pancreatitis and pancreatic cancer: A systematic review with machine learning

BACKGROUND

Resveratrol (RES), a common type of plant polyphenols, has demonstrated promising therapeutic efficacy and safety in animal models of pancreatitis and pancreatic cancer. However, a comprehensive analysis of these data is currently unavailable. This study aimed to systematically review the preclinical evidence regarding RES's effects on animal models of pancreatitis and pancreatic cancer via meta-analyses and optimised machine learning techniques.

METHODS

Animal studies published from inception until June 30th 2024, were systematically retrieved and manually filtrated across databases including PubMed, EMBASE, Web of Science, Ovid MEDLINE, Scopus, and Cochrane Library. Methodological quality of the included studies was evaluated following the SYRCLE's RoB tool. Predefined outcomes included histopathology and relevant biochemical parameters for acute pancreatitis, and tumour weight/tumour volume for pancreatic cancer, comparing treatment and model groups. Pooled effect sizes of the outcomes were calculated using STATA 17.0 software. Machine learning techniques were employed to predict the optimal usage and dosage of RES in pancreatitis models.

RESULTS

A total of 50 studies comprising 33 for acute pancreatitis, 1 chronic pancreatitis, and 16 for pancreatic cancer were included for data synthesis after screening 996 records. RES demonstrated significant improvements on pancreatic histopathology score, pancreatic function parameters (serum amylase and lipase), inflammatory markers (TNF-α, IL-1β, IL-6, and pancreatic myeloperoxidase), oxidative biomarkers (malondialdehyde and superoxide dismutase), and lung injury (lung histopathology and myeloperoxidase) in acute pancreatitis models. In pancreatic cancer models, RES notably reduced tumour weight and volume. Machine learning highlighted tree-structured Parzen estimator-optimised gradient boosted decision tree model as achieving the best performance, identifying course after disease induction, total dosage, single dosage, and total number of doses as critical factors for improving pancreatic histology. Optimal single dosage was 20-105 mg/kg with 3 to 9 doses.

CONCLUSION

This study comprehensively demonstrates the therapeutic effects of RES in mitigating pancreatitis and pancreatic cancer in animal models. Anti-inflammatory, anti-oxidative, and anti-tumour growth properties are potential mechanisms of action for RES.

Histones are critical toxic factors in gut lymph of severe acute pancreatitis: Neutralization by baicalin and baicalein for protection

BACKGROUND

Whether circulating histones in gut lymph contribute to organ failure and impact of chaiqin chengqi decoction (CQCQD) on histones in severe acute pancreatitis (SAP) remain elusive.

PURPOSE

To verify the role of histones in gut lymph of SAP and evaluate the effect of the CQCQD on them.

METHODS

Sodium taurocholate was retrogradely infused into pancreatobiliary duct to induce SAP in rodents. Various regimens of CQCQD were administered intragastrically or via duodenum followed by dynamic gut lymph collection in rats. The impact of gut lymph and histones on endothelial cell viability and lymphocytes was determined. Components of CQCQD in gut lymph were identified by UHPLC-MS and their binding activities with histones were quantified by biolayer interferometry followed by validation in vitro and in vivo in mice.

RESULTS

The histone level was significantly increased in gut lymph of SAP at various time points assessed, closely correlating with multiple organ injury (MOI) indices and contemporary cell viability. Inhibition of histones reduced cytotoxicity induced by SAP-conditioned gut lymph. CQCQD reduced apoptotic cell death in mesenteric lymph nodes, histone level, and cytotoxicity of gut lymph, alleviating MOI parameters. Baicalin and baicalein were amongst top 13 identified CQCQD components absorbed into gut lymph to actively bind histones, block membrane disruption and calcium influx of lymphocytes, and inhibit their cytotoxicity. Both baicalin and baicalein mitigated histone- and SAP-induced MOI indices in mice.

CONCLUSION

Histones are key toxic factors in the gut lymph of SAP and their antagonism by baicalin and baicalein offers a novel therapeutic strategy.

Molecular mechanisms of pain in acute pancreatitis: recent basic research advances and therapeutic implications

Although severe abdominal pain is the main symptom of acute pancreatitis, its mechanisms are poorly understood. An emerging body of literature evidence indicates that neurogenic inflammation might play a major role in modulating the perception of pain from the pancreas. Neurogenic inflammation is the result of a crosstalk between injured pancreatic tissue and activated neurons, which leads to an auto-amplification loop between inflammation and pain during the progression of acute pancreatitis. In this review, we summarize recent findings on the role of neuropeptides, ion channels, and the endocannabinoid system in acute pancreatitis-related pain. We also highlight potential therapeutic strategies that could be applied for managing severe pain in this disease.

Prospect of Mesenchymal Stem-Cell-Conditioned Medium in the Treatment of Acute Pancreatitis: A Systematic Review

Mesenchymal stem cells (MSCs) have demonstrated potential in both clinical and pre-clinical research for mitigating tissue damage and inflammation associated with acute pancreatitis (AP) via paracrine mechanisms. Hence, there has been a recent surge of interest among researchers in utilizing MSC cultured medium (CM) and its components for the treatment of AP, which is recognized as the primary cause of hospitalization for gastrointestinal disorders globally. A systematic review was conducted by searching the MEDLINE, EMBASE, and Web of Science databases. Studies that involve the administration of MSC-CM, extracellular vesicles/microvesicles (EVs/MVs), or exosomes to AP animal models are included. A total of six research studies, including eight experiments, were identified as relevant. The findings of this study provide evidence in favor of a beneficial impact of MSC-CM on both clinical and immunological outcomes. Nevertheless, prior to clinical trials, large animal models should be used and prolonged observation periods conducted in pre-clinical research. Challenges arise due to the lack of standardization and consensus on isolation processes, quantifications, and purity testing, making it difficult to compare reports and conduct meta-analyses in MSC-CM-based therapies.

Upregulation of the ERRγ-VDAC1 axis underlies the molecular pathogenesis of pancreatitis

Emerging evidence suggest that transcription factors play multiple roles in the development of pancreatitis, a necroinflammatory condition lacking specific therapy. Estrogen-related receptor γ (ERRγ), a pleiotropic transcription factor, has been reported to play a vital role in pancreatic acinar cell (PAC) homeostasis. However, the role of ERRγ in PAC dysfunction remains hitherto unknown. Here, we demonstrated in both mice models and human cohorts that pancreatitis is associated with an increase in ERRγ gene expression via activation of STAT3. Acinar-specific ERRγ haploinsufficiency or pharmacological inhibition of ERRγ significantly impaired the progression of pancreatitis both in vitro and in vivo. Using systematic transcriptomic analysis, we identified that voltage-dependent anion channel 1 (VDAC1) acts as a molecular mediator of ERRγ. Mechanistically, we showed that induction of ERRγ in cultured acinar cells and mouse pancreata enhanced VDAC1 expression by directly binding to specific site of the Vdac1 gene promoter and resulted in VDAC1 oligomerization. Notably, VDAC1, whose expression and oligomerization were dependent on ERRγ, modulates mitochondrial Ca2+ and ROS levels. Inhibition of the ERRγ-VDAC1 axis could alleviate mitochondrial Ca2+ accumulation, ROS formation and inhibit progression of pancreatitis. Using two different mouse models of pancreatitis, we showed that pharmacological blockade of ERRγ-VDAC1 pathway has therapeutic benefits in mitigating progression of pancreatitis. Likewise, using PRSS1R122H-Tg mice to mimic human hereditary pancreatitis, we demonstrated that ERRγ inhibitor also alleviated pancreatitis. Our findings highlight the importance of ERRγ in pancreatitis progression and suggests its therapeutic intervention for prevention and treatment of pancreatitis.

Circulating monocytes in acute pancreatitis

Acute pancreatitis is a common gastrointestinal disease characterized by inflammation of the exocrine pancreas and manifesting itself through acute onset of abdominal pain. It is frequently associated with organ failure, pancreatic necrosis, and death. Mounting evidence describes monocytes - phagocytic, antigen presenting, and regulatory cells of the innate immune system - as key contributors and regulators of the inflammatory response and subsequent organ failure in acute pancreatitis. This review highlights the recent advances of dynamic change of numbers, phenotypes, and functions of circulating monocytes as well as their underling regulatory mechanisms with a special focus on the role of lipid modulation during acute pancreatitis.

Role of glycodeoxycholic acid to induce acute pancreatitis in Macaca nemestrina

BACKGROUND

Acute pancreatitis exhibits a rapid clinical progression which makes it difficult to observe in human; hence, an experimental animal model is needed. This preliminary study performed an induction of acute pancreatitis using glycodeoxycholic acid (GDOC) in an experimental macaque model.

METHODS

GDOC injections (initial dose of 11.20 mg/kg) were administered in an escalating manner at specific time points. The injection was given along the bilio-pancreatic duct, followed by measurement of vital signs, serum amylase-lipase, TNF-α, procalcitonin, oxidative stress parameters, and microscopic and macroscopic findings.

RESULTS

The results indicated that acute pancreatitis occurred following induction with low-dose GDOC. Serum amylase and lipase levels increased with subsequent GDOC injections. Blood pressure and heart rate were elevated, indicating abdominal pain. Changes in TNF-α, procalcitonin, and oxidative stress values showed active inflammation. We observed histologic features of pancreatitis and as the dose increased, vasodilation of the splanchnic vasculatures was observed.

CONCLUSIONS

Small dose GDOC injection in the bilio-pancreatic duct may have a role to induce acute pancreatitis in Macaca nemestrina.

Chymase as a Novel Therapeutic Target in Acute Pancreatitis

Acute pancreatitis is still a life-threatening disease without an evidenced therapeutic agent. In this study, the effect of chymase in acute pancreatitis and the possible effect of a chymase inhibitor in acute pancreatitis were investigated. Hamsters were subcutaneously administered 3.0 g/kg of L-arginine to induce acute pancreatitis. Biological markers were measured 1, 2, and 8 h after L-arginine administration. To investigate the effect of a chymase inhibitor, a placebo (saline) or a chymase inhibitor TY-51469 (30 mg/kg) was given 1 h after L-arginine administration. The survival rates were evaluated for 24 h after L-arginine administration. Significant increases in serum lipase levels and pancreatic neutrophil numbers were observed at 1 and 2 h after L-arginine administration, respectively. Significant increases in pancreatic neutrophil numbers were observed in the placebo-treated group, but they were significantly reduced in the TY-51469-treated group. A significant increase in the pancreatic tumor necrosis factor-α mRNA level was observed in the placebo-treated group, but it disappeared in the TY-51469-treated group. Chymase activity significantly increased in the placebo-treated group, but it was significantly reduced by treatment with TY-51469. The survival rate significantly improved in the TY-51469-treated group. A chymase inhibitor may become a novel therapeutic agent for acute pancreatitis.

Metabolomic-based clinical studies and murine models for acute pancreatitis disease: A review

Acute pancreatitis (AP) is one of the most common gastroenterological disorders requiring hospitalization and is associated with substantial morbidity and mortality. Metabolomics nowadays not only help us to understand cellular metabolism to a degree that was not previously obtainable, but also to reveal the importance of the metabolites in physiological control, disease onset and development. An in-depth understanding of metabolic phenotyping would be therefore crucial for accurate diagnosis, prognosis and precise treatment of AP. In this review, we summarized and addressed the metabolomics design and workflow in AP studies, as well as the results and analysis of the in-depth of research. Based on the metabolic profiling work in both clinical populations and experimental AP models, we described the metabolites with potential utility as biomarkers and the correlation between the altered metabolites and AP status. Moreover, the disturbed metabolic pathways correlated with biological function were discussed in the end. A practical understanding of current and emerging metabolomic approaches applicable to AP and use of the metabolite information presented will aid in designing robust metabolomics and biological experiments that result in identification of unique biomarkers and mechanisms, and ultimately enhanced clinical decision-making.

The positive effect of eugenol on acute pancreatic tissue injury: a rat experimental model

Introduction

we present a rat experimental model used to evaluate the possible reduction in the extent of pancreatic tissue injury in acute pancreatitis cases, after administration of eugenol.

Methods

one hundred and twenty Wistar rats were used, which were randomly assigned in 3 groups: sham (n=20), control (n=50) and eugenol (n=50). Acute pancreatitis was induced by biliopancreatic ligation in the control and eugenol groups, but not in the Sham group. In the eugenol group, eugenol was administered per-os. Five histopathological parameters, such as edema, inflammatory infiltration, duct dilatation, hemorrhage and acinar necrosis were evaluated.

Results

at 72 h from acute pancreatitis induction, the total histological score was diminished in the eugenol group (p<0.0005) and duct dilatation and inflammatory infiltration were reduced compared to the control group (p<0.05). In addition, at 72 h, eugenol reduced pancreatic myeloperoxidase activity (p<0.0005).

Conclusion

eugenol, a highly free radical scavenger agent, may have a preventive role in acute pancreatic injury, as it was evident in our rat experimental model.

Role of Bile Acids and Bile Salts in Acute Pancreatitis: From the Experimental to Clinical Studies

ABSTRACT

Acute pancreatitis (AP) is one of the most common gastroenterological disorders leading to hospitalization. It has long been debated whether biliary AP, about 30% to 50% of all cases, is induced by bile acids (BAs) when they reach the pancreas via reflux or via the systemic blood circulation.Besides their classical function in digestion, BAs have become an attractive research target because of their recently discovered property as signaling molecules. The underlying mechanisms of BAs have been investigated in various studies. Bile acids are internalized into acinar cells through specific G-protein-coupled BA receptor 1 and various transporters. They can further act via different receptors: the farnesoid X, ryanodine, and inositol triphosphate receptor. Bile acids induce a sustained Ca2+ influx from the endoplasmic reticulum and release of Ca2+ from acidic stores into the cytosol of acinar cells. The overload of intracellular Ca2+ results in mitochondrial depolarization and subsequent acinar cell necrosis. In addition, BAs have a biphasic effect on pancreatic ductal cells. A more detailed characterization of the mechanisms through which BAs contribute to the disease pathogenesis and severity will greatly improve our understanding of the underlying pathophysiology and may allow for the development of therapeutic and preventive strategies for gallstone-inducedAP.

Experimental Acute Pancreatitis Models: History, Current Status, and Role in Translational Research

Acute pancreatitis is a potentially severe inflammatory disease that may be associated with a substantial morbidity and mortality. Currently there is no specific treatment for the disease, which indicates an ongoing demand for research into its pathogenesis and development of new therapeutic strategies. Due to the unpredictable course of acute pancreatitis and relatively concealed anatomical site in the retro-peritoneum, research on the human pancreas remains challenging. As a result, for over the last 100 years studies on the pathogenesis of this disease have heavily relied on animal models. This review aims to summarize different animal models of acute pancreatitis from the past to present and discuss their main characteristics and applications. It identifies key studies that have enhanced our current understanding of the pathogenesis of acute pancreatitis and highlights the instrumental role of animal models in translational research for developing novel therapies.

Loss of Wasl improves pancreatic cancer outcome

Several studies have suggested an oncogenic role for the neural Wiskott-Aldrich syndrome protein (N-WASP, encoded by the Wasl gene), but thus far, little is known about its function in pancreatic ductal adenocarcinoma (PDAC). In this study, we performed in silico analysis of WASL expression in PDAC patients and found a correlation between low WASL expression and prolonged survival. To clarify the role of Wasl in pancreatic carcinogenesis, we used 2 oncogenic Kras-based PDAC mouse models with pancreas-specific Wasl deletion. In line with human data, both mouse models had an increased survival benefit due to either impaired tumor development in the presence of the tumor suppressor Trp53 or the delayed tumor progression and senescent phenotype upon genetic ablation of Trp53. Mechanistically, loss of Wasl resulted in cell-autonomous senescence through displacement of the N-WASP binding partners WASP-interacting protein (WIP) and p120ctn; vesicular accumulation of GSK3β, as well as YAP1 and phosphorylated β-catenin, which are components of the destruction complex; and upregulation of Cdkn1a(p21), a master regulator of senescence. Our findings, thus, indicate that Wasl functions in an oncogenic manner in PDAC by promoting the deregulation of the p120-catenin/β-catenin/p21 pathway. Therefore, strategies to reduce N-WASP activity might improve the survival outcomes of PDAC patients.

Precision medicine for acute pancreatitis: current status and future opportunities

Acute pancreatitis is a common inflammatory condition affecting the pancreas, predominantly caused by gallstones, alcohol excess, and hypertriglyceridaemia, with severe disease carrying up to 50% mortality. Despite significant research and preclinical promise, no targeted drug treatments exist for the disease and precision medicine approaches are lacking significantly, when compared to other health conditions. Advances in omics applications will facilitate improved preclinical models and target identification as well as biomarker discovery for refined trial design, focusing on risk stratification, subject selection, and outcome determination. Randomised treatment of Acute Pancreatitis with Infliximab: Double-blind, placebo-controlled, multi-centre trial (RAPID-I) is a pioneering trial, currently under way in acute pancreatitis, which may serve as an innovative model for the implementation of precision medicine strategies for acute pancreatitis in the future.

SRT1720 ameliorates sodium taurocholate-induced severe acute pancreatitis in rats by suppressing NF-κB signalling

Severe acute pancreatitis (SAP) is a medical emergency that is often associated with multiple organ failure and high mortality. Although an SAP diagnosis requires prompt treatment, therapeutic options remain limited. SRT1720 is a newly formulatedSIRT1 activator that exerts multiple pharmacological activities with beneficial health effects. However, its potential as an SAP treatment has not been explored. The current study assessed the effect of SRT1720 on a rat model of sodium taurocholate-induced SAP and explored the underlying mechanism. SAP was induced in rats by retrograde injection of a 3.5% sodium taurocholate solution (1 ml/kg) in the biliopancreatic duct. SRT1720 (5 mg/kg) was administered intraperitoneally after sodium taurocholate exposure. Serum samples were analysed for inflammatory cytokine levels and select enzymatic activities using the enzyme-linked immunosorbent assay and commercial enzyme activity assay kits, respectively; protein expression levels were evaluated by western blotting; mRNA levels of biomarkers were determined by quantitative real-time PCR; histopathological changes were analysed by haematoxylin and eosin staining and immunohistochemistry.SRT1720 treatment significantly reduced serum amylase, lipase, pancreatic histological scores, proinflammatory cytokine (TNF-α and IL-6) levels, and expression of NF-κB and p65 in sodium taurocholate-induced SAP rats. Importantly, the treatment stimulated SIRT1 and IκBα levels in pancreatic tissue. Our data suggest that SRT1720 protects rats from sodium taurocholate-induced SAP by suppressing the NF-κB signalling pathway.

Protective effects of flavonoids from Coreopsis tinctoria Nutt. on experimental acute pancreatitis via Nrf-2/ARE-mediated antioxidant pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Oxidative stress is a prominent feature of clinical acute pancreatitis (AP). Coreopsis tinctoria has been used traditionally to treat pancreas disorders like diabetes mellitus in China and Portugal and its flavonoid-rich fraction contain the main phytochemicals that have antioxidant and anti-inflammatory activities.

AIM OF THE STUDY

To investigate the effects of flavonoids isolated from C. tinctoria on experimental AP and explore the potential mechanism.

MATERIALS AND METHODS

LC-MS based online technique was used to analyse and isolate targeted flavonoids from C. tinctoria. Freshly isolated mouse pancreatic acinar cells were treated with taurocholic acid sodium salt hydrate (NaT, 5 mM) with or without flavonoids. Fluorescence microscopy and a plate reader were used to determine necrotic cell death pathway activation (propidium iodide), reactive oxygen species (ROS) production (H2-DCFDA) and ATP depletion (luminescence) where appropriate. AP was induced by 7 repeated intraperitoneal caerulein injections (50 μg/kg) at hourly interval in mice or retrograde infusion of taurolithocholic acid 3-sulfate disodium salt (TLCS; 5 mM, 50 μL) into the pancreatic duct in mice or infusion of NaT (3.5%, 1 mL/kg) in rats. A flavonoid was intraperitoneally administered at 0, 4, and 8 h after the first caerulein injection or post-operation. Disease severity, oxidative stress and antioxidant markers were determined.

RESULTS

Total flavonoids extract and flavonoids 1-6 (C1-C6) exhibited different capacities in reducing necrotic cell death pathway activation with 0.5 mM C1, (2 R,3 R)-taxifolin 7-O-β-D-glucopyranoside, having the best effect. C1 also significantly reduced NaT-induced ROS production and ATP depletion. C1 at 12.5 mg/kg and 8.7 mg/kg (equivalent to 12.5 mg/kg for mice) significantly reduced histopathological, biochemical and immunological parameters in the caerulein-, TLCS- and NaT-induced AP models, respectively. C1 administration increased pancreatic nuclear factor erythroid 2-related factor 2 (Nrf2) and Nrf2-medicated haeme oxygenase-1 expression and elevated pancreatic antioxidant enzymes superoxide dismutase and glutathione peroxidase levels.

CONCLUSIONS

Flavonoid C1 from C. tinctoria was protective in experimental AP and this effect may at least in part be attributed to its antioxidant effects by activation of Nrf2-mediated pathways. These results suggest the potential utilisation of C. tinctoria to treat AP.

Ulinastatin ameliorates tissue damage of severe acute pancreatitis through modulating regulatory T cells

BACKGROUND

Ulinastatin or urinary trypsin inhibitor (UTI) has been shown to ameliorate the inflammatory response induced by experimental severe acute pancreatitis (SAP) and hence reduce the mortality, however the mechanism of its action remains incompletely understood. We have investigated the effect of ulinastatin on regulatory T-cells (Tregs) in an established rat model of SAP.

METHODS

We established a rat SAP model by injecting 5% Na-taurocholate into the pancreatic duct and treated the SAP rats with ulinastatin with different dose level (5000, 10000, 30000 U/kg) through intraperitoneal injection at 0, 6 and 12 h.

RESULTS

We showed that the tissue damage of pancreas and the mortality of the SAP rats were significantly reduced by ulinastatin. We also showed that in the SAP rats the frequencies of CD4+ T cells and Tregs, as well as the expressions of TGF-β1, CTLA-4, and Foxp3 were decreased in the SAP animals while IL-1β, IL-10 and TNF-α were significantly increased. Treatment with ulinastatin up-regulated the proportion of Tregs in CD4+ T cells and the expression of IL-10, Foxp3 and CTLA-4 in the SAP rats in a dose dependence fashion, while down-regulating the levels of L-1β and TNF-α, myeloperoxidase (MPO) activity.

CONCLUSIONS

Our findings suggest that ulinastatin alleviates inflammatory response and tissue damage in SAP rats by increasing the proportion of Tregs. Our study provides a new mechanism for the beneficial effect of ulinastatin in SAP rat model.

The predominance of a naive T helper cell subset in the immune response of experimental acute pancreatitis

INTRODUCTION

In necrotizing acute pancreatitis (NAP), systemic inflammatory response syndrome (SIRS) and the compensatory anti-inflammatory response syndrome (CARS) decide overall outcome and mortality. In patients, low lymphocyte counts were found, but T-helper cells seemed to conversely increase. Our aim was to further categorize T-helper cells within the context of NAP induced SIRS and CARS.

METHODS

NAP was induced by injection of sodium-taurocholate into the common bile duct of male BALB/c mice; sham treated animals received saline infusion. The animals were sacrificed at 6, 12, 24 and 48 h later. Lymphocytes from blood, liver and spleen were isolated and examined by flow cytometry. Staining was performed for CD4, CD8, CD19, CD45RB, CD25, CD69, and CD152. CD4⁺ cells were sorted for their CD45RB expression and sought for gene regulation associated to T_H1/T_H2 cells by quantitative RT-PCR.

RESULTS

In NAP, CD4⁺ was solely increased in all compartments. CD8⁺ remained without substantial alterations. CD45RB showed significant expression in RB^high in T-helper cells, confirmed by the CD45RB^high/low ratio (Liver, 24 h: NAP 2.2, SHAM 0.6; p < 0.001). CD45RB^high and ^-low cells were not associated to patterns of T_H1/T_H2 expression. In NAP, CCR4 expression was significantly decreased within RB^high cells (fold change: 0.04, p < 0.05), while TLR6 showed significant overexpression (fold change: 2.36, p < 0.05).

CONCLUSION

T-helper cells increase in NAP, leaning towards CD45RB^high expression. They resemble naive T-cells, in which NAP leads to expression profiles associated with an innate immune response. This suggests new findings in immunological pathomechanisms of NAP.

Pathogenic mechanisms of pancreatitis

Pancreatitis is inflammation of pancreas and caused by a number of factors including pancreatic duct obstruction, alcoholism, and mutation in the cationic trypsinogen gene. Pancreatitis is represented as acute pancreatitis with acute inflammatory responses and; chronic pancreatitis characterized by marked stroma formation with a high number of infiltrating granulocytes (such as neutrophils, eosinophils), monocytes, macrophages and pancreatic stellate cells (PSCs). These inflammatory cells are known to play a central role in initiating and promoting inflammation including pancreatic fibrosis, i.e., a major risk factor for pancreatic cancer. A number of inflammatory cytokines are known to involve in promoting pancreatic pathogenesis that lead pancreatic fibrosis. Pancreatic fibrosis is a dynamic phenomenon that requires an intricate network of several autocrine and paracrine signaling pathways. In this review, we have provided the details of various cytokines and molecular mechanistic pathways (i.e., Transforming growth factor-β/SMAD, mitogen-activated protein kinases, Rho kinase, Janus kinase/signal transducers and activators, and phosphatidylinositol 3 kinase) that have a critical role in the activation of PSCs to promote chronic pancreatitis and trigger the phenomenon of pancreatic fibrogenesis. In this review of literature, we discuss the involvement of several pro-inflammatory and anti-inflammatory cytokines, such as in interleukin (IL)-1, IL-1β, IL-6, IL-8 IL-10, IL-18, IL-33 and tumor necrosis factor-α, in the pathogenesis of disease. Our review also highlights the significance of several experimental animal models that have an important role in dissecting the mechanistic pathways operating in the development of chronic pancreatitis, including pancreatic fibrosis. Additionally, we provided several intermediary molecules that are involved in major signaling pathways that might provide target molecules for future therapeutic treatment strategies for pancreatic pathogenesis.

The toll-like receptor 4 antagonist transforming growth factor-β-activated kinase(TAK)-242 attenuates taurocholate-induced oxidative stress through regulating mitochondrial function in mice pancreatic acinar cells

BACKGROUND

Acute pancreatitis (AP) is a commonly occurring and potentially life-threatening disease. Recently, toll-like receptor 4 (TLR4) has been considered as a new clue for studying the pathogenesis of AP due to its important role in inflammatory response cascade.

MATERIALS AND METHODS

The aim of this study was to investigate the potential protective effect of transforming growth factor-β-activated kinase (TAK)-242, a novel TLR4 antagonist, in taurocholate-treated mice pancreatic acinar cells. The protective effects were measured by cell viability, lactate dehydrogenase release and apoptosis, and oxidative stress was assayed by lipid peroxidation and oxidative enzyme activities. To determine the potential underlying mechanisms, mitochondrial cytochrome c release, swelling, and calcium buffering capacity were measured in isolated mitochondria, and mitochondrial biogenesis and expression of mitochondrial dynamic proteins were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot.

RESULTS

Treatment with 6-mM taurocholate significantly increased the expression of TLR4 at both mRNA and protein levels. TAK-242 markedly increased cell viability, decreased lactate dehydrogenase release, and inhibited apoptotic cell death as measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining in pancreatic acinar cells. These protective effects were accompanied by the suppressed lipid peroxidation and enhanced endogenous antioxidative enzyme activity. Using isolated and purified mitochondria from pancreatic acinar cells, we found that TAK-242 treatment also inhibited cytochrome c release into the cytoplasm, mitochondrial swelling, and decrease in mitochondrial Ca2+ buffering capacity after taurocholate exposure. In addition, TAK-242 significantly promoted mitochondrial biogenesis, as evidenced by increased mtDNA and upregulated mitochondrial transcription factors. The results of Western blot analysis showed that TAK-242 also differently regulated the expression of mitochondrial fusion and fission proteins.

CONCLUSIONS

All these data strongly indicated that blocking TLR4 activity via TAK-242 exerts protective effects in an in vitro AP model, and it could be a possible strategy to improve clinical outcome in AP patients.

Hydrogen sulphide exacerbates acute pancreatitis by over-activating autophagy via AMPK/mTOR pathway

Previously, we have shown that hydrogen sulphide (H₂ S) might be pro-inflammatory during acute pancreatitis (AP) through inhibiting apoptosis and subsequently favouring a predominance of necrosis over apoptosis. In this study, we sought to investigate the detrimental effects of H₂ S during AP specifically with regard to its regulation on the impaired autophagy. The incubated levels of H₂ S were artificially intervened by an administration of sodium hydrosulphide (NaHS) or DL-propargylglycine (PAG) after AP induction. Accumulation of autophagic vacuoles and pre-mature activation of trypsinogen within acini, which indicate the impairment of autophagy during AP, were both exacerbated by treatment with NaHS but attenuated by treatment with PAG. The regulation that H₂ S exerted on the impaired autophagy during AP was further attributed to over-activation of autophagy rather than hampered autophagosome-lysosome fusion. To elucidate the molecular mechanism that underlies H₂ S-mediated over-activation of autophagy during AP, we evaluated phosphorylations of AMP-activated protein kinase (AMPK), AKT and mammalian target of rapamycin (mTOR). Furthermore, Compound C (CC) was introduced to determine the involvement of mTOR signalling by evaluating phosphorylations of downstream effecters including p70 S6 kinase (P70S6k) and UNC-51-Like kinase 1 (ULK1). Our findings suggested that H₂ S exacerbated taurocholate-induced AP by over-activating autophagy via activation of AMPK and subsequently, inhibition of mTOR. Thus, an active suppression of H₂ S to restore over-activated autophagy might be a promising therapeutic approach against AP-related injuries.

An optimised mouse model of chronic pancreatitis with a combination of ethanol and cerulein

Introduction

Chronic pancreatitis (CP) is an intractable and multi-factorial disorder. Developing appropriate animal models is an essential step in pancreatitis research, and the best ones are those which mimic the human disorder both aetiologically and pathophysiologically. The current study presents an optimised protocol for creating a murine model of CP, which mimics the initial steps of chronic pancreatitis in alcohol chronic pancreatitis and compares it with two other mouse models treated with cerulein or ethanol alone.

Material and methods

Thirty-two male C57BL/6 mice were randomly selected, divided into four groups, and treated intraperitoneally with saline (10 ml/kg, control group), ethanol (3 g/kg; 30% v/v), cerulein (50 µg/kg), or ethanol + cerulein, for six weeks. Histopathological and immunohistochemical assays for chronic pancreatitis index along with real-time PCR assessments for mRNA levels of inflammatory cytokines and fibrogenic markers were conducted to verify the CP induction.

Results

The results indicated that CP index (CPI) was significantly increased in ethanol-cerulein mice compared to the saline, ethanol, and cerulein groups (p < 0.001). Interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), transforming growth factor β (TGF-β), α-smooth muscle actin (α-SMA), and myeloperoxidase activity were also significantly greater in both cerulein and ethanol-cerulein groups than in the saline treated animals (p < 0.001). Immunohistochemical analysis revealed enhanced expression of TGF-β and α-SMA in ethanol-cerulein mice compared to the saline group.

Conclusions

Intraperitoneal (IP) injections of ethanol and cerulein could successfully induce CP in mice. IP injections of ethanol provide higher reproducibility compared to ethanol feeding. The model is simple, non-invasive, reproducible, and time-saving. Since the protocol mimics the initial phases of CP development in alcoholics, it can be used for investigating basic mechanisms and testing new therapies.

Translational Insights Into Peroxisome Proliferator-Activated Receptors in Experimental Acute Pancreatitis

Acute pancreatitis (AP) is an inflammatory disorder of the exocrine pancreas frequently associated with metabolic causes, contributing factors, or consequences, including hypertriglyceridemia, obesity, and disorders of intermediary metabolism, respectively. To date, there is no specific therapy for this disease. Future optimal therapy should correct both inflammatory and metabolic components of the disease. Peroxisome proliferator-activated receptors (PPARs) are lipid-sensing nuclear receptors that control inflammatory and metabolic pathways via ligand-dependent and ligand-independent mechanisms. There are 3 known subtypes, PPAR-α, PPAR-β/δ, and PPAR-γ, which are differentially expressed in various tissues. The PPARs interact closely with other transcription factors such as nuclear factor κB and signal tranducers and activators of transcription that have pivotal roles in the pathobiology of AP. In this comprehensive review, we summarize the role of PPARs in AP, highlighting important in vitro and in vivo experimental findings. Finally, we propose future research directions as well as potential translational use of PPAR agonists in the treatment of AP.

A novel, protective role of ursodeoxycholate in bile-induced pancreatic ductal injury

We have previously shown that chenodeoxycholic acid (CDCA) strongly inhibits pancreatic ductal HCO3 (-) secretion through the destruction of mitochondrial function, which may have significance in the pathomechanism of acute pancreatitis (AP). Ursodeoxycholic acid (UDCA) is known to protect the mitochondria against hydrophobic bile acids and has an ameliorating effect on cell death. Therefore, our aim was to investigate the effect of UDCA pretreatment on CDCA-induced pancreatic ductal injury. Guinea pig intrainterlobular pancreatic ducts were isolated by collagenase digestion. Ducts were treated with UDCA for 5 and 24 h, and the effect of CDCA on intracellular Ca(2+) concentration ([Ca(2+)]i), intracellular pH (pHi), morphological and functional changes of mitochondria, and the rate of apoptosis were investigated. AP was induced in rat by retrograde intraductal injection of CDCA (0.5%), and the disease severity of pancreatitis was assessed by measuring standard laboratory and histological parameters. Twenty-four-hour pretreatment of pancreatic ducts with 0.5 mM UDCA significantly reduced the rate of ATP depletion, mitochondrial injury, and cell death induced by 1 mM CDCA and completely prevented the inhibitory effect of CDCA on acid-base transporters. UDCA pretreatment had no effect on CDCA-induced Ca(2+) signaling. Oral administration of UDCA (250 mg/kg) markedly reduced the severity of CDCA-induced AP. Our results clearly demonstrate that UDCA 1) suppresses the CDCA-induced pancreatic ductal injury by reducing apoptosis and mitochondrial damage and 2) reduces the severity of CDCA-induced AP. The protective effect of UDCA against hydrophobic bile acids may represent a novel therapeutic target in the treatment of biliary AP.

Polyelectrolyte multilayers assembled from IL-10 plasmid DNA and TGF-β siRNA facilitate chronic pancreatitis treatment

Nanoparticles assembled with IL-10 plasmid DNA and TGF-β siRNA can reduce inflammation and fibrosis in mice with chronic pancreatitis (CP).

Bile acid effects are mediated by ATP release and purinergic signalling in exocrine pancreatic cells

Background

In many cells, bile acids (BAs) have a multitude of effects, some of which may be mediated by specific receptors such the TGR5 or FXR receptors. In pancreas systemic BAs, as well as intra-ductal BAs from bile reflux, can affect pancreatic secretion. Extracellular ATP and purinergic signalling are other important regulators of similar secretory mechanisms in pancreas. The aim of our study was to elucidate whether there is interplay between ATP and BA signalling.

Results

Here we show that CDCA (chenodeoxycholic acid) caused fast and concentration-dependent ATP release from acini (AR42J) and duct cells (Capan-1). Taurine and glycine conjugated forms of CDCA had smaller effects on ATP release in Capan-1 cells. In duct monolayers, CDCA stimulated ATP release mainly from the luminal membrane; the releasing mechanisms involved both vesicular and non-vesicular secretion pathways. Duct cells were not depleted of intracellular ATP with CDCA, but acinar cells lost some ATP, as detected by several methods including ATP sensor AT1.03^YEMK. In duct cells, CDCA caused reversible increase in the intracellular Ca²⁺ concentration [Ca^{2 +}]_i, which could be significantly inhibited by antagonists of purinergic receptors. The TGR5 receptor, expressed on the luminal side of pancreatic ducts, was not involved in ATP release and Ca²⁺ signals, but could stimulate Na⁺/Ca²⁺ exchange in some conditions.

Conclusions

CDCA evokes significant ATP release that can stimulate purinergic receptors, which in turn increase [Ca²⁺]_i. The TGR5 receptor is not involved in these processes but can play a protective role at high intracellular Ca²⁺ conditions. We propose that purinergic signalling could be taken into consideration in other cells/organs, and thereby potentially explain some of the multifaceted effects of BAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12964-015-0107-9) contains supplementary material, which is available to authorized users.

Loss of Bace1 in mice does not alter the severity of caerulein induced pancreatitis

Context

Beta-site alpha-amyloid protein cleaving enzyme1 (BACE1) plays a key role in the pathogenesis of Alzheimer’s disease. Additional to its moderate expression in the brain, high levels of BACE1 mRNA were found in the pancreas. Murine Bace1 has been immunohistochemicaly detected at the apical pole of acinar cells within the exocrine pancreas of mice and Bace1 activity was observed in pancreatic juice. In vitro experiments revealed enteropeptidase as a putative substrate for Bace1 suggesting a role in acute pancreatitis.

Objective

The aim of this study was to address a protective mechanism of Bace1 in acute experimental pancreatitis in mice.

Methods

Acute experimental pancreatitis was induced by intraperitoneal injection of caerulein in homozygote Bace1^-/- mice and wild type mice. Serum and tissue analyses were carried out after 4 h, 8 h and 24 h. Measurement of plasma amylase and lipase was performed to confirm pancreatitis induction. In order to assess the severity of pancreatitis H&E stained pancreatic sections were examined regarding edema, inflammation and apoptosis. Immunohistochemical detection of myeloperoxidase (MPO) positive cells was carried out to further quantify the extent of inflammation. Expression of Bace2 within the pancreas was analyzed by immunohistochemistry and RT-qPCR.

Results

We demonstrate that total loss of Bace1 in mice leads to no alterations in the course of acute experimental caerulein-pancreatitis. Bace1^-/- mice develop a moderate pancreatitis that is comparable in histomorphological and serological features with those seen in wild type mice.

Discussion

We discuss the results in the context of the applied caerulein induced edematous pancreatitis model and possible compensatory mechanisms via Bace2 that might be responsible for the observed results.

Nicotine ameliorates experimental severe acute pancreatitis via enhancing immunoregulation of CD4+ CD25+ regulatory T cells

OBJECTIVES

Activation of "nicotinic anti-inflammatory pathway" could reduce severity of inflammation and injury induced by acute pancreatitis. However, the role of regulatory T (Treg) cells in this pathway is unclear.

METHODS

Severe acute pancreatitis (SAP) was induced in mice through retrograde injection of 50-μL 2% Na-taurocholate into the pancreatic duct of the mouse. In nicotine treatment group, nicotine (50, 100, and 300 μg/kg) was administered 1 hour before and after SAP operation through intraperitoneal injection. We compared the properties of Treg cell percentage and specific marker such as cytotoxic T-lymphocyte antigen 4 and forkhead box transcription factor forkhead/winged helix transcription factor p3 on Treg using quantitative reverse transcription polymerase chain reaction and flow cytometry. All experiment animal serum cytokines were measured using enzyme-linked immunosorbent assay. One-way analysis of variance was applied to evaluate the experimental data and for statistical comparisons. The survival rate data were analyzed using the log-rank test.

RESULTS

Nicotine significantly protected mice from lethal SAP in a dose-dependent fashion by inhibiting tissue injury, digestive enzyme production, and proinflammatory cytokines production. Moreover, nicotine up-regulated the number and suppressive capacity of CD4 CD25 Treg via inducing the expression of immunoregulatory molecules and transforming growth factor β1 elevation.

CONCLUSIONS

Modulating immunoregulation of CD4 CD25 Treg is a critical mechanism for nicotinic anti-inflammatory pathway and it may be feasible to use selective agonists as an immunotherapy for SAP.

Anti-inflammation and anti-fibrosis with PEGylated, apigenin loaded PLGA nanoparticles in chronic pancreatitis disease

In this work, apigenin, a drug that can inhibit pancreatic stellate cell fibrosis, is loaded into PEGylated PLGA nanoparticles to treat the inflammation and fibrosis associated with chronic pancreatitis (CP).

Application of caerulein and lipopolysaccharides in creating mouse models of mild or severe acute pancreatitis

AIM: To establish typical mouse models of mild or severe acute pancreatitis induced with caerulein (CAE) and/or lipopolysaccharides (LPS).

METHODS: Fifty healthy adult male C57 mice were randomly divided into five groups (with 10 mice in each group): a control group (CON group), the caerulein 7 group (CAE 7 group), a caerulein 7 plus LPS group (CAE 7 + LPS group), a caerulein 13 group (CAE 13 group), and a caerulein 13 plus LPS group (CAE 13 + LPS group). All the animals were killed three hours after the last intraperitoneal injection. The pancreas was carefully removed for microscopic examination and further observed under a transmission electron microscope (TEM). Serum amylase and lipase concentrations were assayed.

RESULTS: Enzyme levels and pathological score in all the experimental groups were significantly higher than those in the CON group (amylase lowest CAE 7 group: 27020 U/dL ± 3443 U/dL vs CON group: 2696 U/dL ± 400 U/dL, P < 0.01; lipase content lowest CAE 7 group: 1379 U/L ± 283 U/L vs CON group: 33 U/L ± 13 U/L, P < 0.01; pathological score lowest CAE 7 group: 5.8 ± 0.9 vs CON group: 0.1 ± 0.3, P < 0.01). Compared with the CAE 7 group, the enzyme levels and pathological score in the CAE 13 + LPS group increased more significantly (CAE 13 + LPS group amylase: 46969 U/dL ± 11852 U/dL vs CAE 7 group amylase: 27020 U/dL ± 3443 U/dL, P < 0.01; CAE13 + LPS group lipase: 1962 U/dL ± 496 U/dL vs CAE 7 group lipase: 1379 U/dL ± 283 U/dL, P < 0.05; CAE13 + LPS group pathological score : 11.1 ± 1.1 vs CAE 7 group pathological score : 5.8 ± 0.9, P < 0.05). The grade of pathological changes in the CAE 13 + LPS group was significantly higher than that in the CAE 13 group (CAE 13 + LPS group: 11.1 ± 1.1 vs CAE 13 group: 10.1 ± 0.99, P < 0.05). The ultrastructure of acinar cells was damaged in the CAE 7 group, and the rough endoplasmic reticulum and mitochondria were markedly swollen. However, in the CAE 13 + LPS group, the acinar cells were seriously damaged.

CONCLUSION: Caerulein alone by intraperitoneal injection 7 times can be used to prepare a typical model of acute edematous pancreatitis, and caerulein by intraperitoneal injection 13 times plus LPS at the last time can be used to produce typical acute necrotizing pancreatitis.

Cytoprotective effect of 1-nitro-2-phenylethane in mice pancreatic acinar cells subjected to taurocholate: putative role of guanylyl cyclase-derived 8-nitro-cyclic-GMP

The nitroderivative 1-nitro-2-phenylethane (NPE) was recently described as a compound possessing heme-dependent soluble guanylyl cyclase (sGC) stimulating properties in vascular smooth muscle cells. In this study, we tested such pharmacological property of NPE in mice pancreatic acinar cells subjected to the bile salt taurocholate, a type of pathological stimulus that simulates pancreatitis. Here, isolated acinar cells were treated with NPE in order to assess the role of sGC on the detrimental effects induced by taurocholate. NPE reduced taurocholate-elicited Ca(2+) overload, production of reactive oxygen species (ROS), apoptosis, necrosis, and exerted a protective effect against mitochondrial membrane potential (ΔΨm) dissipation. These NPE-induced effects were abolished by pretreatment with ODQ and KT 5823, and after the blockade of nitric oxide (NO) synthase with l-NAME, inhibitors of key components of the sGC pathway. Contrarily to cGMP that alone increased ΔΨm collapse and cell damage, the cytoprotective effect of NPE on ΔΨm and cell necrosis was almost reproduced by 8-nitro-cGMP, a second messenger generated by sGC under oxidative stress conditions. In conclusion, putative sGC stimulation with NPE reveals its cytoprotective profile on pancreatic cells subjected to taurocholate. Moreover, ROS and NO conjunctly appear to drive sGC activity in pancreatic acinar cells to implement an adaptive mechanism in response to oxidative and Ca(2+) stress through 8-nitro-cGMPsynthesis.

Catalpol ameliorates sodium taurocholate-induced acute pancreatitis in rats via inhibiting activation of nuclear factor kappa B

Catalpol, an iridoid glucoside extracted from the traditional Chinese herbal medicine, Rehmannia glutinosa, is reported to exert neuroprotective, anti-inflammatory, anti-tumor and anti-apoptotic effects. The main aim of the present study was to investigate whether catalpol ameliorates experimental acute pancreatitis (AP) induced by sodium taurocholate (STC). AP was induced in rats via retrograde injection of 4% STC (0.1 mL/100 g) into the biliopancreatic duct. Rats were pre-treated with saline or catalpol (50 mg/kg) 2 h before STC injection. At 12, 24 and 48 h after injection, the severity of AP was evaluated using biochemical and morphological analyses. Pretreatment with catalpol led to a significant reduction in serum amylase and lipase activities, pancreatic histological damage, myeloperoxidase (MPO) activity, interleukin (IL)-1β, IL-6 and TNF-α levels, and activation of nuclear factor kappa B (NF-κB). Moreover, administration of catalpol increased the viability of pancreatic acinar cells and inhibited NF-κB expression in vitro. Our results collectively support the potential of catalpol as a highly effective therapeutic agent for treatment of AP.

Time course of intestinal barrier function injury in a sodium taurocholate-induced severe acute pancreatitis in rat model

OBJECTIVE

The aims of this study were to clarify the kinetics of intestinal barrier function impairment in sodium taurocholate-induced severe acute pancreatitis (SAP) models and to explore an appropriate concentration of sodium taurocholate and a suitable time point for further study.

METHODS

In total, 104 rats were randomly divided into four groups: the normal control group (n = 8) receiving no treatment, the sham-operation group (n = 32), the 2.5% and 5% sodium taurocholate-treated SAP groups (n = 32 for each group) which were induced via a retrograde injection of 2.5% or 5% sodium taurocholate into the pancreatic duct. Histological examination, serum D-lactate and endotoxin levels and the incidence of bacteria translocation were recorded to assess the intestinal mucosal injury.

RESULTS

Pancreatitis models were successfully established in both the 2.5% and 5% sodium taurocholate-treated groups. The dosage of sodium taurocholate used to induce pancreatitis was positively correlated with the degree of intestinal mucosal injury. The most severe damage to intestinal barrier was observed 24 h after surgery in the 2.5% sodium taurocholate-treated group and 48 h after surgery in the 5% sodium taurocholate-treated group, respectively.

CONCLUSION

Based on the success rate of the model, the mortality and the impairment of intestinal barrier function, we conclude that 24 h after a retrograde injection of 2.5% sodium taurocholate may be the most appropriate time point to study intestinal barrier injury in SAP rats.

Berberine ameliorates severe acute pancreatitis‑induced intestinal barrier dysfunction via a myosin light chain phosphorylation‑dependent pathway

Berberine is a traditional drug used to treat gastrointestinal disorders in China and has been demonstrated to attenuate intestinal barrier dysfunction in certain animal models. However, the effects of berberine on pancreatitis-induced intestinal barrier dysfunction are yet to be fully elucidated. This study aimed to investigate the effect of berberine pretreatment on the attenuation of intestinal barrier dysfunction induced by severe acute pancreatitis (SAP). A total of 36 rats were randomly divided into Sham, SAP and SAP plus berberine groups. Pancreatitis was induced using retrograde injection of 3% Na-taurocholate into the pancreatic duct. Histological examinations of the pancreas were performed and intestinal barrier dysfunction was characterized by histological measurements and the assessment of serum diamine oxidase activity and endotoxin levels. Zonula occludens-1 and occludin mRNA and protein expression, as well as myosin light chain (MLC) phosphorylation, were assessed. SAP rat models were successfully established. Berberine treatment was found to have no significant effect on the histological changes in the pancreas, but was observed to ameliorate the intestinal mucosal barrier damage and membrane permeability associated with SAP. Although berberine exerted minimal effects on tight junction proteins in the ilea of SAP rats, it was observed to significantly inhibit SAP-induced MLC phosphorylation. To the best of our knowledge, this is the first study to demonstrate that berberine attenuates SAP‑induced intestinal barrier dysfunction in vivo. In addition, this study shows that the effect of berberine on intestinal barrier function may be associated with the inhibition of SAP‑induced upregulation of MLC phosphorylation.

Oxidative stress in acute pancreatitis: lost in translation?

Oxidative stress has been implicated in the pathogenesis of acute pancreatitis, a severe and debilitating inflammation of the pancreas that carries a significant mortality, and which imposes a considerable financial burden on the health system due to patient care. Although extensive efforts have been directed towards the elucidation of critical underlying mechanisms and the identification of novel therapeutic targets, the disease remains without a specific therapy. In experimental animal models of acute pancreatitis, increased oxidative stress and decreased antioxidant defences have been observed, changes also detected in patients clinically. However, despite the promise of studies evaluating the effects of antioxidants in these model systems, translation to the clinic has thus far been disappointing. This may reflect many factors involved in the design of both preclinical and clinical evaluations of antioxidant therapy, not least the fact that most experimental studies have focussed on pre-treatment rather than post-injury assessment. This review has examined evidence relating to the involvement of oxidative stress in the pathophysiology of acute pancreatitis, focussing on experimental models and the clinical experience, including the experimental techniques employed and potential of antioxidant therapy.

The SLC10 carrier family: transport functions and molecular structure

The SLC10 family represents seven genes containing 1-12 exons that encode proteins in humans with sequence lengths of 348-477 amino acids. Although termed solute carriers (SLCs), only three out of seven (i.e. SLC10A1, SLC10A2, and SLC10A6) show sodium-dependent uptake of organic substrates across the cell membrane. These include the uptake of bile salts, sulfated steroids, sulfated thyroidal hormones, and certain statin drugs by SLC10A1 (Na(+)-taurocholate cotransporting polypeptide (NTCP)), the uptake of bile salts by SLC10A2 (apical sodium-dependent bile acid transporter (ASBT)), and uptake of sulfated steroids and sulfated taurolithocholate by SLC10A6 (sodium-dependent organic anion transporter (SOAT)). The other members of the family are orphan carriers not all localized in the cell membrane. The name "bile acid transporter family" arose because the first two SLC10 members (NTCP and ASBT) are carriers for bile salts that establish their enterohepatic circulation. In recent years, information has been obtained on their 2D and 3D membrane topology, structure-transport relationships, and on the ligand and sodium-binding sites. For SLC10A2, the putative 3D morphology was deduced from the crystal structure of a bacterial SLC10A2 analog, ASBT(NM). This information was used in this chapter to calculate the putative 3D structure of NTCP. This review provides first an introduction to recent knowledge about bile acid synthesis and newly found bile acid hormonal functions, and then describes step-by-step each individual member of the family in terms of expression, localization, substrate pattern, as well as protein topology with emphasis on the three functional SLC10 carrier members.

Autocrine Sonic hedgehog attenuates inflammation in cerulein-induced acute pancreatitis in mice via upregulation of IL-10

Hedgehog signaling plays critical roles in pancreatic oncogenesis and chronic pancreatitis, but its roles in acute pancreatitis (AP) are largely ambiguous. In this study, we provide evidence that Sonic hedgehog (Shh), but neither Desert hedgehog (Dhh) nor Indian hedgehog (Ihh), is the main protein whose expression is activated during the development of cerulein-induced acute pancreatitis in mice, and the Shh serves as an anti-inflammation factor in an autocrine manner. Blocking autocrine Shh signaling with anti-Shh neutralizing antibody aggravates the progression of acute pancreatitis. Mechanistic insight into Shh signaling activation in acute pancreatitis indicates that inflammatory stimulation activates Shh expression and secretion, and subsequently upregulates the expression and secretion of interleukin-10 (IL-10). Moreover, inhibition of Shh signaling with neutralizing antibody abolishes IL-10 production in vivo and in vitro. Molecular biological studies show that autocrine Shh signaling activates the key transcriptional factor Gli1 so that the target gene IL-10 is upregulated, leading to the protective and anti-inflammatory functions in the mouse model of acute pancreatitis. Thus, this study suggests autocrine Shh signaling functions as a protective signaling in the progression of acute pancreatitis.