Pancreatic acinar cell: its role in acute pancreatitis

Increase of serum pancreatic enzymes during hospitalization for acute heart failure

AIMS

Acute heart failure (AHF) is associated with end-organ dysfunction. The effect of AHF on the pancreas has not been studied. We aim to evaluate serum markers of pancreatic damage during hospitalization for AHF.

METHODS AND RESULTS

In data from the Pragmatic Urinary Sodium-based treatment algoritHm in Acute Heart Failure (PUSH-AHF) study, amylase and lipase values were extracted from available serum samples at baseline, and at 24 and 72 h after hospitalization. The differences between pancreatic enzymes between timepoints were evaluated using the Friedman test. Associations with N-terminal pro-B-type natriuretic peptide (NT-proBNP) were tested using linear regression analysis. The study population consisted of 274 patients. Mean age was 73 ± 11 years, and 117 (43%) were women. Mean left ventricular ejection fraction (LVEF) was 38 ± 14%; 53 (19%) patients had HF with a preserved LVEF (≥50%). At baseline, median amylase and lipase were within normal range (47 [33-63] U/L and 30 [21-44] U/L, respectively). Both enzymes significantly increased in the first 72 h (P-value for trend <0.001); mean change was 9 ± 22 U/L for amylase, and 10 ± 22 U/L for lipase. Moreover, NT-proBNP at baseline showed a positive correlation with mean change in pancreatic enzymes in 72 h (P = 0.02 for amylase and P = 0.006 for lipase).

CONCLUSION

Patients admitted for AHF exhibited a significant increase in serum values of pancreatic enzymes in the first 72 h, suggesting that an episode of AHF affects the pancreatic tissue. This rise in pancreatic enzymes was associated with HF severity, as reflected by NT-proBNP.

Alterations in exocrine pancreatic function after acute pancreatitis

Exocrine pancreatic dysfunction (EPD) is a malabsorptive complication of pancreatic disorders that can lead to a host of symptoms ranging from flatulence to diarrhea and contribute to weight loss and metabolic bone disease. It is increasingly recognized to occur after acute pancreatitis (AP), including episodes with mild severity. The risk of developing EPD after AP is influenced by a range of factors, including the degree of acinar cell destruction and inflammation during AP, and persistent structural derangements following AP. In this article, we discuss the epidemiology, pathophysiology, and clinical management of EPD after AP while highlighting key knowledge gaps.

Pancreatic Ubap2 deletion regulates glucose tolerance, inflammation, and protection from cerulein-induced pancreatitis

Ubiquitin-binding associated protein 2 (UBAP2) is reported to promote macropinocytosis and pancreatic adenocarcinoma (PDAC) growth, however, its role in normal pancreatic function remains unknown. We addressed this knowledge gap by generating UBAP2 knockout (U2KO) mice under a pancreas-specific Cre recombinase (Pdx1-Cre). Pancreatic architecture remained intact in U2KO animals, but they demonstrated slight glucose intolerance compared to controls. Upon cerulein challenge to induce pancreatitis, U2KO animals had reduced levels of several pancreatitis-relevant cytokines, amylase and lipase in the serum, reduced tissue damage, and lessened neutrophil infiltration into the pancreatic tissue. Mechanistically, cerulein-challenged U2KO animals revealed reduced NF-κB activation compared to controls. In vitro promoter binding studies confirmed the reduction of NF-κB binding to its target molecules supporting UBAP2 as a new regulator of inflammation in pancreatitis and may be exploited as a therapeutic target in future to inhibit pancreatitis.

Estimation of exocrine pancreatic insufficiency in children with acute pancreatitis using the 13C mixed triglyceride breath test

BACKGROUND

/Objective: The extent of exocrine pancreatic insufficiency (EPI) in the paediatric population with acute pancreatitis (AP) is unknown. The primary objective was to use a 6 h stable-isotope breath test to determine the prevalence of EPI in children with AP. The secondary objective was to determine the diagnostic ability of a 4 h abbreviated breath test in the detection of EPI.

METHODS

13C-mixed triglyceride (MTG) breath test was used to measure fat digestibility in 12 children with AP and 12 normal children. EPI was diagnosed based on a cumulative dose percentage recovery (cPDR) cut-off value < 26.8% present in literature. To reduce the test burden, the diagnostic accuracy of an abbreviated 4 h test was evaluated, using a cPDR cut-off that was the 2.5th percentile of its distribution in control children.

RESULTS

The cPDR of cases was significantly lower than that of controls (27.71 ± 7.88% vs 36.37 ± 4.70%, p = 0.005). The cPDR during acute illness was not significantly different to that at 1 month follow up (24.69 ± 6.83% vs 26.98 ± 11.10%, p = 0.52). The 4 h and 6 h breath test results correlated strongly (r = 0.93, p < 0.001) with each other. The new 4 h test had 87.5% sensitivity and 93.8% specificity for detecting EPI.

CONCLUSION

Two-thirds (66.7%) of this sample of children with AP had EPI during admission, which persisted at 1 month follow up. The 4 h abbreviated 13C-MTG breath test has good diagnostic ability to detect EPI in children and may improve its clinical utility in this age group.

Salidroside ameliorates severe acute pancreatitis-induced cell injury and pyroptosis by inactivating Akt/NF-κB and caspase-3/GSDME pathways

Our previous studies showed that Salidroside (Sal), a glucoside of the phenylpropanoid tyrosol isolated from Rhodiola rosea L, alleviated severe acute pancreatitis (SAP) by inhibiting inflammation. However, the detailed mechanism remains unclear. Recent evidence has indicated a critical role of Sal in ameliorating inflammatory disorders by regulating pyroptosis. The present study aimed to explore the involvement of Sal and pyroptosis in the pathogenesis of SAP and investigate the potential mechanism. The effects of Sal on pyroptosis were first evaluated using SAP rat and cell model. Our results revealed that Sal treatment significantly decreased SAP-induced pancreatic cell damage and pyroptosis in vivo and in vitro, as well as reduced the release of lactate dehydrogenase (LDH), IL-1β and IL-18. Search Tool for Interacting Chemicals (STITCH) online tool identified 4 genes (CASP3, AKT1, HIF1A and IL10) as candidate targets of Sal in both rattus norvegicus and homo sapiens. Western blot and immunohistochemistry staining validated that Sal treatment decreased the phosphorylation levels of Akt and NF-κB p65, as well as cleaved caspase-3 and N-terminal fragments of GSDME (GSDME-N), suggesting that Sal might suppress pyroptosis through inactivating Akt/NF-κB and Caspase-3/GSDME pathways. Furthermore, overexpression of AKT1 or CASP3 could partially reverse the inhibitory effects of Sal on cell injury and pyroptosis, while downregulation of AKT1 or CASP3 promoted the inhibitory effects of Sal. Taken together, our data indicate that Sal suppresses SAP-induced pyroptosis through inactivating Akt/NF-κB and Caspase-3/GSDME pathways.

Blockade of the protease ADAM17 ameliorates experimental pancreatitis

Acute and chronic pancreatitis, the latter associated with fibrosis, are multifactorial inflammatory disorders and leading causes of gastrointestinal disease-related hospitalization. Despite the global health burden of pancreatitis, currently, there are no effective therapeutic agents. In this regard, the protease A Disintegrin And Metalloproteinase 17 (ADAM17) mediates inflammatory responses through shedding of bioactive inflammatory cytokines and mediators, including tumor necrosis factor α (TNFα) and the soluble interleukin (IL)-6 receptor (sIL-6R), the latter of which drives proinflammatory IL-6 trans-signaling. However, the role of ADAM17 in pancreatitis is unclear. To address this, Adam17^ex/ex mice-which are homozygous for the hypomorphic Adam17^ex allele resulting in marked reduction in ADAM17 expression-and their wild-type (WT) littermates were exposed to the cerulein-induced acute pancreatitis model, and acute (1-wk) and chronic (20-wk) pancreatitis models induced by the cigarette smoke carcinogen nicotine-derived nitrosamine ketone (NNK). Our data reveal that ADAM17 expression was up-regulated in pancreatic tissues of animal models of pancreatitis. Moreover, the genetic (Adam17^ex/ex mice) and therapeutic (ADAM17 prodomain inhibitor [A17pro]) targeting of ADAM17 ameliorated experimental pancreatitis, which was associated with a reduction in the IL-6 trans-signaling/STAT3 axis. This led to reduced inflammatory cell infiltration, including T cells and neutrophils, as well as necrosis and fibrosis in the pancreas. Furthermore, up-regulation of the ADAM17/IL-6 trans-signaling/STAT3 axis was a feature of pancreatitis patients. Collectively, our findings indicate that the ADAM17 protease plays a pivotal role in the pathogenesis of pancreatitis, which could pave the way for devising novel therapeutic options to be deployed against this disease.

Nutritional impact of mycotoxins in food animal production and strategies for mitigation

Mycotoxins are toxic secondary metabolites produced by filamentous fungi that are commonly detected as natural contaminants in agricultural commodities worldwide. Mycotoxin exposure can lead to mycotoxicosis in both animals and humans when found in animal feeds and food products, and at lower concentrations can affect animal performance by disrupting nutrient digestion, absorption, metabolism, and animal physiology. Thus, mycotoxin contamination of animal feeds represents a significant issue to the livestock industry and is a health threat to food animals. Since prevention of mycotoxin formation is difficult to undertake to avoid contamination, mitigation strategies are needed. This review explores how the mycotoxins aflatoxins, deoxynivalenol, zearalenone, fumonisins and ochratoxin A impose nutritional and metabolic effects on food animals and summarizes mitigation strategies to reduce the risk of mycotoxicity.

pH-Dependence of Glucose-Dependent Activity of Beta Cell Networks in Acute Mouse Pancreatic Tissue Slice

Extracellular pH has the potential to affect various aspects of the pancreatic beta cell function. To explain this effect, a number of mechanisms was proposed involving both extracellular and intracellular targets and pathways. Here, we focus on reassessing the influence of extracellular pH on glucose-dependent beta cell activation and collective activity in physiological conditions. To this end we employed mouse pancreatic tissue slices to perform high-temporally resolved functional imaging of cytosolic Ca²⁺ oscillations. We investigated the effect of either physiological H⁺ excess or depletion on the activation properties as well as on the collective activity of beta cell in an islet. Our results indicate that lowered pH invokes activation of a subset of beta cells in substimulatory glucose concentrations, enhances the average activity of beta cells, and alters the beta cell network properties in an islet. The enhanced average activity of beta cells was determined indirectly utilizing cytosolic Ca²⁺ imaging, while direct measuring of insulin secretion confirmed that this enhanced activity is accompanied by a higher insulin release. Furthermore, reduced functional connectivity and higher functional segregation at lower pH, both signs of a reduced intercellular communication, do not necessary result in an impaired insulin release.

Chemokine receptor 8 expression may be linked to disease severity and elevated interleukin 6 secretion in acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disease, which presents with epigastric pain and is clinically diagnosed by amylase and lipase three times the upper limit of normal. The 2012 Atlanta classification stratifies the severity of AP as one of three risk categories namely, mild AP (MAP), moderately severe AP (MSAP), and severe AP (SAP). Challenges in stratifying AP upon diagnosis suggest that a better understanding of the underlying complex pathophysiology may be beneficial.

AIM

To identify the role of the chemokine receptor 8 (CCR8), expressed by T-helper type-2 Lymphocytes and peritoneal macrophages, and its possible association to Interleukin (IL)-6 and AP stratification.

METHODS

This study was a prospective case-control study. A total of 40 patients were recruited from the Chris Hani Baragwanath Academic Hospital and the Charlotte Maxeke Johannesburg Academic Hospital. Bioassays were performed on 29 patients (14 MAP, 11 MSAP, and 4 SAP) and 6 healthy controls as part of a preliminary study. A total of 12 mL of blood samples were collected at Day (D) 1, 3, 5, and 7 post epigastric pain. Using multiplex immunoassay panels, real-time polymerase chain reaction (qRT-PCR) arrays, and multicolour flow cytometry analysis, immune response-related proteins, genes, and cells were profiled respectively. GraphPad Prism™ software and fold change (FC) analysis was used to determine differences between the groups. P<0.05 was considered significant.

RESULTS

The concentration of IL-6 was significantly different at D3 post epigastric pain in both the MAP group and MSAP group with P = 0.001 and P = 0.013 respectively, in a multiplex assay. When a FC of 2 was applied to identify differentially expressed genes using RT² Profiler, CCR8 was shown to increase steadily with disease severity from MAP (1.33), MSAP (38.28) to SAP (1172.45) median FC. Further verification studies using RT-PCR showed fold change increases of CCR8 in MSAP and SAP ranging from 1000 to 1000000 times when represented as Log₁₀, compared to healthy control respectively at D3. The findings also showed differing lymphocyte and monocyte cell frequency between the groups. With monocyte population frequency as high as 70% in MSAP at D3.

CONCLUSION

The higher levels of CCR8 and IL-6 in the severe patients and immune cell differences compared to MAP and controls provide an avenue for exploring AP stratification to improve management.

In Vitro Disease Models of the Endocrine Pancreas

The ethical constraints and shortcomings of animal models, combined with the demand to study disease pathogenesis under controlled conditions, are giving rise to a new field at the interface of tissue engineering and pathophysiology, which focuses on the development of in vitro models of disease. In vitro models are defined as synthetic experimental systems that contain living human cells and mimic tissue- and organ-level physiology in vitro by taking advantage of recent advances in tissue engineering and microfabrication. This review provides an overview of in vitro models and focuses specifically on in vitro disease models of the endocrine pancreas and diabetes. First, we briefly review the anatomy, physiology, and pathophysiology of the human pancreas, with an emphasis on islets of Langerhans and beta cell dysfunction. We then discuss different types of in vitro models and fundamental elements that should be considered when developing an in vitro disease model. Finally, we review the current state and breakthroughs in the field of pancreatic in vitro models and conclude with some challenges that need to be addressed in the future development of in vitro models.

Engineering of a functional pancreatic acinus with reprogrammed cancer cells by induced PTF1a expression

A pancreatic acinus is a functional unit of the exocrine pancreas producing digest enzymes. Its pathobiology is crucial to pancreatic diseases including pancreatitis and pancreatic cancer, which can initiate from pancreatic acini. However, research on pancreatic acini has been significantly hampered due to the difficulty of culturing normal acinar cells in vitro. In this study, an in vitro model of the normal acinus, named pancreatic acinus-on-chip (PAC), is developed using reprogrammed pancreatic cancer cells. The developed model is a microfluidic platform with an epithelial duct and acinar sac geometry microfabricated by a newly developed two-step controlled "viscous-fingering" technique. In this model, human pancreatic cancer cells, Panc-1, reprogrammed to revert to the normal state upon induction of PTF1a gene expression, are cultured. Bioinformatic analyses suggest that, upon induced PTF1a expression, Panc-1 cells transition into a more normal and differentiated acinar phenotype. The microanatomy and exocrine functions of the model are characterized to confirm the normal acinus phenotypes. The developed model provides a new and reliable testbed to study the initiation and progression of pancreatic cancers.

Direct Endoplasmic Reticulum Targeting by the Selective Alkylphospholipid Analog and Antitumor Ether Lipid Edelfosine as a Therapeutic Approach in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), the most common malignancy of the pancreas, shows a dismal and grim overall prognosis and survival rate, which have remained virtually unchanged for over half a century. PDAC is the most lethal of all cancers, with the highest mortality-to-incidence ratio. PDAC responds poorly to current therapies and remains an incurable malignancy. Therefore, novel therapeutic targets and drugs are urgently needed for pancreatic cancer treatment. Selective induction of apoptosis in cancer cells is an appealing approach in cancer therapy. Apoptotic cell death is highly regulated by different signaling routes that involve a variety of subcellular organelles. Endoplasmic reticulum (ER) stress acts as a double-edged sword at the interface of cell survival and death. Pancreatic cells exhibit high hormone and enzyme secretory functions, and thereby show a highly developed ER. Thus, pancreatic cancer cells display a prominent ER. Solid tumors have to cope with adverse situations in which hypoxia, lack of certain nutrients, and the action of certain antitumor agents lead to a complex interplay and crosstalk between ER stress and autophagy-the latter acting as an adaptive survival response. ER stress also mediates cell death induced by a number of anticancer drugs and experimental conditions, highlighting the pivotal role of ER stress in modulating cell fate. The alkylphospholipid analog prototype edelfosine is selectively taken up by tumor cells, accumulates in the ER of a number of human solid tumor cells-including pancreatic cancer cells-and promotes apoptosis through a persistent ER-stress-mediated mechanism both in vitro and in vivo. Here, we discuss and propose that direct ER targeting may be a promising approach in the therapy of pancreatic cancer, opening up a new avenue for the treatment of this currently incurable and deadly cancer. Furthermore, because autophagy acts as a cytoprotective response to ER stress, potentiation of the triggering of a persistent ER response by combination therapy, together with the use of autophagy blockers, could improve the current gloomy expectations for finding a cure for this type of cancer.

Chronic Pancreatitis and the Development of Pancreatic Cancer

Pancreatitis is a fibro-inflammatory disorder of the pancreas that can occur acutely or chronically as a result of the activation of digestive enzymes that damage pancreatic cells, which promotes inflammation. Chronic pancreatitis with persistent fibro-inflammation of the pancreas progresses to pancreatic cancer, which is the fourth leading cause of cancer deaths across the globe. Pancreatic cancer involves cross-talk of inflammatory, proliferative, migratory, and fibrotic mechanisms. In this review, we discuss the role of cytokines in the inflammatory cell storm in pancreatitis and pancreatic cancer and their role in the activation of SDF1α/CXCR4, SOCS3, inflammasome, and NF-κB signaling. The aberrant immune reactions contribute to pathological damage of acinar and ductal cells, and the activation of pancreatic stellate cells to a myofibroblast-like phenotype. We summarize several aspects involved in the promotion of pancreatic cancer by inflammation and include a number of regulatory molecules that inhibit that process.

Neuroregulatory role of ginkgolides

The application of ginkgolides as a herbal remedy reaches ancient China. Over time many studies confirmed the neuroprotective effect of standard Ginkgo biloba tree extract—the only available ginkgolide source. Ginkgolides present a wide variety of neuroregulatory properties, commonly used in the therapy process of common diseases, such as Alzheimer’s, Parkinson’s, and many other CNS-related diseases and disorders. The neuroregulative properties of ginkgolides include the conditioning of neurotransmitters action, e.g., glutamate or dopamine. Besides, natural compounds induce the inhibition of platelet-activating factors (PAF). Furthermore, ginkgolides influence the inflammatory process. This review focuses on the role of ginkgolides as neurotransmitters or neuromodulators and overviews their impact on the organism at the molecular, cellular, and physiological levels. The clinical application of ginkgolides is discussed as well.

Hepatocyte Growth Factor and Macrophage-stimulating Protein "Hinge" Analogs to Treat Pancreatic Cancer

Pancreatic cancer (PC) ranks twelfth in frequency of diagnosis but is the fourth leading cause of cancer related deaths with a 5 year survival rate of less than 7 percent. This poor prognosis occurs because the early stages of PC are often asymptomatic. Over-expression of several growth factors, most notably vascular endothelial growth factor (VEGF), has been implicated in PC resulting in dysfunctional signal transduction pathways and the facilitation of tumor growth, invasion and metastasis. Hepatocyte growth factor (HGF) acts via the Met receptor and has also received research attention with ongoing efforts to develop treatments to block the Met receptor and its signal transduction pathways. Macrophage-stimulating protein (MSP), and its receptor Ron, is also recognized as important in the etiology of PC but is less well studied. Although the angiotensin II (AngII)/AT1 receptor system is best known for mediating blood pressure and body water/electrolyte balance, it also facilitates tumor vascularization and growth by stimulating the expression of VEGF. A metabolite of AngII, angiotensin IV (AngIV) has sequence homology with the "hinge regions" of HGF and MSP, key structures in the growth factor dimerization processes necessary for Met and Ron receptor activation. We have developed AngIV-based analogs designed to block dimerization of HGF and MSP and thus receptor activation. Norleual has shown promise as tested utilizing PC cell cultures. Results indicate that cell migration, invasion, and pro-survival functions were suppressed by this analog and tumor growth was significantly inhibited in an orthotopic PC mouse model.

The role of asparagine synthetase on nutrient metabolism in pancreatic disease

The pancreas avidly takes up and synthesizes the amino acid asparagine (Asn), in part, to maintain an active translational machinery that requires incorporation of the amino acid. The de novo synthesis of Asn in the pancreas occurs through the enzyme asparagine synthetase (ASNS). The pancreas has the highest expression of ASNS of any organ, and it can further upregulate ASNS expression in the setting of amino acid depletion. ASNS expression is driven by an intricate feedback network within the integrated stress response (ISR), which includes the amino acid response (AAR) and the unfolded protein response (UPR). Asparaginase is a cancer chemotherapeutic drug that depletes plasma Asn. However, asparaginase-associated pancreatitis (AAP) is a major medical problem and could be related to pancreatic Asn depletion. In this review, we will provide an overview of ASNS and then describe its role in pancreatic health and in the exocrine disorders of pancreatitis and pancreatic cancer. We will offer the overarching perspective that a high abundance of ASNS expression is hardwired in the exocrine pancreas to buffer the high demands of Asn for pancreatic digestive enzyme protein synthesis, that perturbations in the ability to express or upregulate ASNS could tip the balance towards pancreatitis, and that pancreatic cancers exploit ASNS to gain a metabolic survival advantage.

Inhibition of Matrix Metalloproteinase with BB-94 Protects against Caerulein-Induced Pancreatitis via Modulating Neutrophil and Macrophage Activation

Methods

AP was induced in Balb/C mice by ten hourly intraperitoneal injections of caerulein (100 μg/kg) and LPS (5 mg/kg). The MMP inhibitor, BB-94 (20 mg/kg) was intraperitoneally administered 30 min before AP induction. Pancreatitis was confirmed by histology and serum amylase and lipase. Expression of pancreatic proinflammatory mediators and NF-κB activation were assessed. Bone marrow-derived neutrophils (BMDNs) and macrophages (BMDMs) were isolated. BMDNs were activated by phorbol 12-myristate 13-acetate (PMA, 50 ng/ml) and neutrophil reactive oxygen species (ROS) production was recorded. BMDMs were stimulated with 10 ng/ml IFN-γ and 100 ng/ml LPS to induce M1 macrophage polarization.

Results

Pancreatic MMP-9 was markedly upregulated and serum MMP-9 was increased in caerulein-induced pancreatitis. Inhibition of MMP with BB-94 ameliorated pancreatic tissue damage and decreased the expression of proinflammatory cytokines (TNFα and IL-6) or chemokines (CCL2 and CXCL2) and NF-κB activation. Furthermore, using isolated BMDNs and BMDMs, we found that inhibition of MMP with BB-94 markedly decreased neutrophil ROS production, inhibited inflammatory macrophage polarization and NF-κB activation.

Conclusions

Our results showed that inhibition of MMP with BB-94 protected against pancreatic inflammatory responses in caerulein-induced pancreatitis via modulating neutrophil and macrophage activation.

Current trends in pharmacological approaches for treatment and management of acute pancreatitis – a review

Objectives

Acute pancreatitis (AP) is an inimical disorder associated with overall mortality rates between 10-15%. It is a disorder of the exocrine pancreas which is characterized by local and systemic inflammatory responses primarily driven by oxidative stress and death of pancreatic acinar cells. The severity of AP ranges from mild pancreatic edema with complete recuperative possibilities to serious systemic inflammatory response resulting in peripancreatic/pancreatic necrosis, multiple organ failure, and death.

Key findings

We have retrieved the potential alternative approaches that are developed lately for efficacious treatment of AP from the currently available literature and recently reported experimental studies. This review summarizes the need for alternative approaches and combinatorial treatment strategies to deal with AP based on literature search using specific key words in PubMed and ScienceDirect databases.

Summary

Since AP results from perturbations of multiple signaling pathways, the so called “monotargeted smart drugs” of the past decade is highly unlikely to be effective. Also, the conventional treatment approaches were mainly involved in providing palliative care instead of curing the disease. Hence, many researchers are beginning to focus on developing alternate therapies to treat AP effectively. This review also summarizes the recent trends in the combinatorial approaches available for AP treatment.

Jayaweera S, A. Dias D, Sharopov F, Taheri Y, Martins N, Baghalpour N, C. Cho W, Sharifi-Rad J. Therapeutic Potential of α- and β-Pinene: A Miracle Gift of Nature

α- and β-pinene are well-known representatives of the monoterpenes group, and are found in many plants' essential oils. A wide range of pharmacological activities have been reported, including antibiotic resistance modulation, anticoagulant, antitumor, antimicrobial, antimalarial, antioxidant, anti-inflammatory, anti-Leishmania, and analgesic effects. This article aims to summarize the most prominent effects of α- and β-pinene, namely their cytogenetic, gastroprotective, anxiolytic, cytoprotective, anticonvulsant, and neuroprotective effects, as well as their effects against H2O2-stimulated oxidative stress, pancreatitis, stress-stimulated hyperthermia, and pulpal pain. Finally, we will also discuss the bioavailability, administration, as well as their biological activity and clinical applications.

Ward-based Goal-Directed Fluid Therapy (GDFT) in Acute Pancreatitis (GAP) trial: study protocol for a feasibility randomised controlled trial

INTRODUCTION

Acute pancreatitis is an inflammatory disease of the pancreas with high risk of developing multiorgan failure and death. There are no effective pharmacological interventions used in current clinical practice. Maintaining fluid and electrolyte balance is the mainstay of supportive management. Goal-directed fluid therapy (GDFT) has been shown to decrease morbidity and mortality in surgical conditions with systemic inflammatory response. There is currently no randomised controlled trial (RCT) investigating the role of GDFT based on cardiac output parameters in patients with acute pancreatitis in the ward setting. A feasibility trial was designed to determine patient and clinician support for recruitment into an RCT of ward-based GDFT in acute pancreatitis, adherence to a GDFT protocol, safety, participant withdrawal, and to determine appropriate endpoints for a subsequent larger trial to evaluate efficacy.

METHODS AND ANALYSIS

The GDFT in Acute Pancreatitis trial is a prospective two-centre feasibility RCT. Eligible adults admitted with new onset of acute pancreatitis will be enrolled and randomised into ward-based GDFT (n=25) or standard fluid therapy (n=25) within 6 hours from the diagnosis and continuing for the following 48 hours. Cardiac output parameters will be monitored with a non-invasive device (Cheetah NICOM; Cheetah Medical). The intervention group will consist of a protocolised GDFT approach consisting of stroke volume optimisation with crystalloid fluid boluses, while the control group will receive standard care fluid therapy as advised by the clinical team. The primary endpoint is feasibility. Secondary endpoints will include safety of the intervention, complications, mortality, admission to intensive care unit, cost and quality of life.

ETHICS AND DISSEMINATION

Ethics approval was granted by the London Central Research Ethics Committee (17/LO/1235, project ID: 221872). The results of this trial will be presented to international conference with interest in general surgery and acute care and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ISRCTN36077283.

The antidiabetic properties of the hot water extract of kola nut (Cola nitida (Vent.) Schott & Endl.) in type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cola nitida is amongst the evergreen plants native to West Africa used in the treatment of various ailments including diabetes.

AIM OF THE STUDY

This study aims to investigate the antidiabetic effects of the hot water extract of C. nitida seeds in type 2 diabetic rats.

METHODS

Type 2 diabetic rats were orally administered with low (150 mg/kg bw) and high (300 mg/kg bw) doses of the hot water extract for 6 wk and thereafter, blood glucose, insulin level, lipid profile, pancreatic β-cell function, perfusion and morphology, redox imbalance, glycolytic and cholinergic enzymes, as well as of caspase-3 and Nrf2 expressions were measured.

RESULTS

Treatment with the extract led to significant depletion of blood glucose, serum triglycerides, LDL-cholesterol, fructosamine, ALT, and uric acids, while elevating serum insulin and HDL-cholesterol levels. The infusion also significantly (p < 0.05) elevated GSH level, SOD, catalase, α-amylase, and ATPase activities, with concomitant depletion of myeloperoxidase enzyme activity, and NO and MDA levels in the serum and pancreas. Significantly (p < 0.05) improved pancreatic β-cell function and morphology were observed in rats treated with C. nitida, with restored pancreatic capillary networks. C. nitida inhibited the activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose 6 phosphatase, and acetylcholinesterase while downregulated the Nrf2 expression. NMR analysis of the extract revealed the presence of caffeine and theobromine. The molecular docking studies indicated that identified compounds displayed strong molecular interactions with caspase-3 and Nrf2.

CONCLUSION

These results insinuate the antidiabetic activities of C. nitida hot water extract and may be attributed to the NMR-identified compounds.

UBIAD1 Plays an Essential Role in the Survival of Pancreatic Acinar Cells

UbiA prenyltransferase domain-containing protein 1 (UBIAD1) is a vitamin K₂ biosynthetic enzyme. We previously showed the lethality of this enzyme in UBIAD1 knockout mice during the embryonic stage. However, the biological effects of UBIAD1 deficiency after birth remain unclear. In the present study, we used a tamoxifen-inducible systemic UBIAD1 knockout mouse model to determine the role of UBIAD1 in adult mice. UBIAD1 knockout resulted in the death of the mice within about 60 days of administration of tamoxifen. The pancreas presented with the most prominent abnormality in the tamoxifen-induced UBIAD1 knockout mice. The pancreas was reduced remarkably in size; furthermore, the pancreatic acinar cells disappeared and were replaced by vacuoles. Further analysis revealed that the vacuoles were adipocytes. UBIAD1 deficiency in the pancreatic acinar cells caused an increase in oxidative stress and autophagy, leading to apoptotic cell death in the tamoxifen-induced UBIAD 1 knockout mice. These results indicate that UBIAD1 is essential for maintaining the survival of pancreatic acinar cells in the pancreas.

Dopamine D2 receptor signalling controls inflammation in acute pancreatitis via a PP2A-dependent Akt/NF-κB signalling pathway

BACKGROUND AND PURPOSE

Dopamine has multiple anti-inflammatory effects, but its role and molecular mechanism in acute pancreatitis (AP) are unclear. We investigated the role of dopamine signalling in the inflammatory response in AP.

EXPERIMENTAL APPROACH

Changes in pancreatic dopaminergic system and effects of dopamine, antagonists and agonists of D1 and D2 dopamine receptors were analysed in wild-type and pancreas-specific Drd2-/- mice with AP (induced by caerulein and LPS or L-arginine) and pancreatic acinar cells with or without cholecystokinin (CCK) stimulation. The severity of pancreatitis was assessed by measuring serum amylase and lipase and histological assessments. The NF-κB signalling pathway was evaluated, and macrophage and neutrophil migration assessed by Transwell assay.

KEY RESULTS

Pancreatic dopamine synthetase and metabolic enzyme levels were increased, whereas D1 and D2 receptors were decreased in AP. Dopamine reduced inflammation in CCK-stimulated pancreatic acinar cells by inhibiting the NF-κB pathway. Moreover, the protective effects of dopamine were blocked by a D2 antagonist, but not a D1 antagonist. A D2 agonist reduced pancreatic damage and levels of p-IκBα, p-NF-κBp65, TNFα, IL-1β and IL-6 in AP. Pancreas-specific Drd2-/- aggravated AP. Also, the D2 agonist activated PP2A and inhibited the phosphorylation of Akt, IKK, IκBα and NF-κB and production of inflammatory cytokines and chemokines. Furthermore, it inhibited the migration of macrophages and neutrophils by reducing the expression of CCL2 and CXCL2. A PP2A inhibitor attenuated these protective effects of the D2 agonist.

CONCLUSIONS AND IMPLICATIONS

D2 receptors control pancreatic inflammation in AP by inhibiting NF-κB activation via a PP2A-dependent Akt signalling pathway.

The Interplay between Inflammation, Coagulation and Endothelial Injury in the Early Phase of Acute Pancreatitis: Clinical Implications

Acute pancreatitis (AP) is an inflammatory disease with varied severity, ranging from mild local inflammation to severe systemic involvement resulting in substantial mortality. Early pathologic events in AP, both local and systemic, are associated with vascular derangements, including endothelial activation and injury, dysregulation of vasomotor tone, increased vascular permeability, increased leukocyte migration to tissues, and activation of coagulation. The purpose of the review was to summarize current evidence regarding the interplay between inflammation, coagulation and endothelial dysfunction in the early phase of AP. Practical aspects were emphasized: (1) we summarized available data on diagnostic usefulness of the markers of endothelial dysfunction and activated coagulation in early prediction of severe AP; (2) we reviewed in detail the results of experimental studies and clinical trials targeting coagulation-inflammation interactions in severe AP. Among laboratory tests, d-dimer and angiopoietin-2 measurements seem the most useful in early prediction of severe AP. Although most clinical trials evaluating anticoagulants in treatment of severe AP did not show benefits, they also did not show significantly increased bleeding risk. Promising results of human trials were published for low molecular weight heparin treatment. Several anticoagulants that proved beneficial in animal experiments are thus worth testing in patients.

Tissue Renin-Angiotensin System in Lacrimal Gland Fibrosis in a Murine Model of Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (cGVHD) is a serious complication known to occur after allogeneic hematopoietic stem cell transplantation. Clinical manifestation includes inflammation and fibrosis. Many peripheral tissues are capable of generating the renin-angiotensin system (RAS) components, called the tissue RAS, and have various roles in tissue-specific physiological and pathological functions of inflammation and fibrosis. This article reviews evidence for the presence of the tissue RAS in the normal mouse lacrimal gland, the role of the tissue RAS in the fibrotic pathogenesis of the lacrimal gland in cGVHD model mice, and the effect of angiotensin II receptor blockers on preventing lacrimal gland fibrosis. B10.D2→BALB/c (H-2d) major histocompatibility complex-compatible, minor histocompatibility antigen-mismatched mice were used as a model of cGVHD, which reflects the clinical and pathological symptoms of human cGVHD. We also describe the localization of RAS components in the normal mouse lacrimal gland. In addition, we characterize the inflammatory and fibrotic changes of the lacrimal gland in cGVHD model mice, demonstrate that fibroblasts strongly express angiotensin II, angiotensin II type 1 receptor (AT1R), and angiotensin II type 2 receptor, and show that mRNA expression of angiotensinogen increased in the lacrimal gland of cGVHD model mice. Inhibitory experiments revealed that lacrimal gland fibrosis was suppressed in mice treated with an AT1R blocker, but not in mice treated with an angiotensin II type 2 receptor blocker. Hence, we conclude that the tissue RAS is involved in the fibrotic pathogenesis of the lacrimal gland and that AT1R blockers have a therapeutic effect on lacrimal gland fibrosis in cGVHD model mice.

No association between losartan use and acute pancreatitis in hypertensive patients

Background and objective

Clinical evidence is scarce about the relationship between losartan use and acute pancreatitis. We therefore conducted a population-based case-control study using the database from the Taiwan National Health Insurance Program to investigate this question.

Methods

The study consisted of 1449 hypertensive subjects aged 20-84 years with a first episode of acute pancreatitis during the period 2000-2011 as the case group and 2479 hypertensive subjects without acute pancreatitis as the control group. Both the case and control groups were matched for sex, age, comorbidities and index year of acute pancreatitis diagnosis. According to the history of losartan prescription before the date of diagnosis of acute pancreatitis, subjects who had never received a prescription for losartan were defined as 'never use of losartan', those whose last remaining losartan tablet was detected within 7 days before the date of diagnosis of acute pancreatitis were defined as 'current use of losartan' and those whose last remaining tablet of losartan was detected ≥8 days before the date of diagnosis of acute pancreatitis were defined as 'late use of losartan'. ORs and 95% CIs were measured to investigate the risk of acute pancreatitis associated with losartan use by the multivariable unconditional logistic regression model.

Results

After adjustment for potentially confounding factors, the adjusted OR of acute pancreatitis was 0.96 (95% CI 0.68 to 1.37) for subjects with current use of losartan compared with those with never use of losartan, but the difference was not statistically significant. For subjects with late use of losartan the adjusted OR of acute pancreatitis was 1.05 (95% CI 0.80 to 1.37), which also was not statistically significant.

Conclusions

No significant association can be detected between losartan use and acute pancreatitis in hypertensive patients. More research is required to determine the potential role of losartan in the risk of acute pancreatitis.

Effect of tiron on remote organ injury in rats with severe acute pancreatitis induced by L-arginine

Acute pancreatitis (AP) is an acute inflammatory disorder of the pancreas that can be complicated by involvement of other remote organs. Oxidative stress is known to have a crucial role in the development of pancreatic acinar damage and one of the main causes in multisystem organ failure in experimental AP. The aim of the study was to determine the effect of tiron on pancreas and remote organ damage in L-arginine (L-Arg) induced AP rat model. Thirty-two male rats were divided in random into four groups: control, tiron, L-Arg, and tiron with L-Arg. At the end of the experiment, blood samples were withdrawn for biochemical analysis. The pancreas, lung, kidney, and liver were collected for histopathological examination. Estimation of pancreatic water content was done. Analysis of pulmonary, hepatic, renal, and pancreatic lipid peroxide levels (MDA), superoxide dismutase (SOD), and reduced glutathione (GSH) were carried out. Finally, nuclear factor kappa B (NF-κB) and transforming growth factor β1 (TGF-β1) expression in pancreatic tissue was determined. Results indicated that treatment with tiron significantly decreased lipid peroxide levels and markedly increased both SOD activity and GSH level. Moreover, histopathological analysis further confirmed that administration of tiron relatively ameliorates pancreatic acinar cells and remote organ damage. Increased immunoreactivity of NF-κB and TGF-β1 were reduced also by tiron treatment. These findings pointed out the protective role of the mitochondrial antioxidant, tiron against AP induced by L-Arg.

Reduced Pancreatic Exocrine Function and Organellar Disarray in a Canine Model of Acute Pancreatitis

The aim of the present study was to investigate the pancreatic exocrine function in a canine model and to analyze the changes in organelles of pancreatic acinar cells during the early stage of acute pancreatitis (AP). AP was induced by retrograde injection of 5% sodium taurocholate (0.5 ml/kg) into the main pancreatic duct of dogs. The induction of AP resulted in serum hyperamylasemia and a marked reduction of amylase activity in the pancreatic fluid (PF). The pancreatic exocrine function was markedly decreased in subjects with AP compared with the control group. After the induction of AP, histological examination showed acinar cell edema, cytoplasmic vacuolization, fibroblasts infiltration, and inflammatory cell infiltration in the interstitium. Electron micrographs after the induction of AP revealed that most of the rough endoplasmic reticulum (RER) were dilated and that some of the ribosomes were no longer located on the RER. The mitochondria were swollen, with shortened and broken cristae. The present study demonstrated, in a canine model, a reduced volume of PF secretion with decreased enzyme secretion during the early stage of AP. Injury of mitochondria and dilatation and degranulation of RER may be responsible for the reduced exocrine function in AP. Furthermore, the present model and results may be useful for researching novel therapeutic measures in AP.

Parathyroid Hormone-Related Protein Interacts With the Transforming Growth Factor-β/Bone Morphogenetic Protein-2/Gremlin Signaling Pathway to Regulate Proinflammatory and Profibrotic Mediators in Pancreatic Acinar and Stellate Cells

OBJECTIVES

Transforming growth factor β (TGF-β) regulates immune and fibrotic responses of chronic pancreatitis. The bone morphogenetic protein 2 (BMP-2) antagonist gremlin is regulated by TGF-β. Parathyroid hormone-related protein (PTHrP) levels are elevated in chronic pancreatitis. Here, we investigated the cross-talk between TGF-β/BMP-2/gremlin and PTHrP signaling.

METHODS

Reverse transcription/real-time polymerase chain reaction, chromatin immunoprecipitation, Western blotting, and transient transfection were used to investigate PTHrP regulation by TGF-β and BMP-2 and gremlin regulation by PTHrP. The PTHrP antagonist PTHrP (7-34) and acinar cells with conditional Pthrp gene deletion (PTHrP) were used to assess PTHrP's role in the proinflammatory and profibrotic effects of TGF-β and gremlin.

RESULTS

Transforming growth factor β increased PTHrP levels in acinar cells and pancreatic stellate cells (PSCs) through a Smad3-dependent pathway. Transforming growth factor β's effects on levels of IL-6 and intercellular adhesion molecule 1 (ICAM-1) (acinar cells) and procollagen I and fibronectin (PSCs) were inhibited by PTHrP (7-34). PTHrP suppressed TGF-β's effects on IL-6 and ICAM-1. Parathyroid hormone-related hormone increased gremlin in acinar cells, and inhibiting gremlin action suppressed TGF-β's and PTHrP's effects on IL-6 and ICAM-1. Transforming growth factor β-mediated gremlin up-regulation was suppressed in PTHrP cells. Bone morphogenetic protein 2 suppressed PTHrP levels in PSCs.

CONCLUSIONS

Parathyroid hormone-related hormone functions as a novel mediator of the proinflammatory and profibrotic effects of TGF-β. Transforming growth factor β and BMP-2 regulate PTHrP expression, and PTHrP regulates gremlin levels.

The effect of renin angiotensin system genetic variants in acute pancreatitis

OBJECTIVES

We sought association of genetic variants in the renin-angiotensin system (RAS) and vitamin D system with acute pancreatitis (AP) development and severity.

BACKGROUND

The endocrine RAS is involved in circulatory homeostasis through the pressor action of angiotensin II at its AT1 receptor. However, local RAS regulate growth and inflammation in diverse cells and tissues, and their activity may be suppressed by vitamin D. Intrapancreatic angiotensin II generation has been implicated in the development of AP.

METHODS

Five hundred forty-four white patients with AP from 3 countries (United Kingdom, 22; Germany, 136; and The Netherlands 386) and 8487 control subjects (United Kingdom 7833, The Netherlands 717) were genotyped for 8 polymorphisms of the RAS/vitamin D systems, chosen on the basis of likely functionality.

RESULTS

The angiotensin-converting enzyme I (rather than D) allele was significantly associated with alcohol-related AP when all cohorts were combined (P = 0.03). The renin rs5707 G (rather than A) allele was associated with AP (P = 0.002), infected necrosis (P = 0.025) and mortality (P = 0.046).

CONCLUSIONS

The association of 2 RAS polymorphisms with AP suggests the need for further detailed analysis of the role of RAS/vitamin D in the genesis or severity of AP, particularly given the ready potential for pharmacological manipulation of this system using existing marketed agents. However, further replication studies will be required before any such association is considered robust, particularly given the significant heterogeneity of AP causation and clinical course.

Acinar cell-specific knockout of the PTHrP gene decreases the proinflammatory and profibrotic responses in pancreatitis

Pancreatitis is a necroinflammatory disease with acute and chronic manifestations. Accumulated damage incurred during repeated bouts of acute pancreatitis (AP) can lead to chronic pancreatitis (CP). Pancreatic parathyroid hormone-related protein (PTHrP) levels are elevated in a mouse model of cerulein-induced AP. Here, we show elevated PTHrP levels in mouse models of pancreatitis induced by chronic cerulein administration and pancreatic duct ligation. Because acinar cells play a major role in the pathophysiology of pancreatitis, mice with acinar cell-specific targeted disruption of the Pthrp gene (PTHrP(Δacinar)) were generated to assess the role of acinar cell-secreted PTHrP in pancreatitis. These mice were generated using Cre-LoxP technology and the acinar cell-specific elastase promoter. PTHrP(Δacinar) exerted protective effects in cerulein and pancreatic duct ligation models, evident as decreased edema, histological damage, amylase secretion, pancreatic stellate cell (PSC) activation, and extracellular matrix deposition. Treating acinar cells in vitro with cerulein increased IL-6 expression and NF-κB activity; these effects were attenuated in PTHrP(Δacinar) cells, as were the cerulein- and carbachol-induced elevations in amylase secretion. The cerulein-induced upregulation of procollagen I expression was lost in PSCs from PTHrP(Δacinar) mice. PTHrP immunostaining was elevated in human CP sections. The cerulein-induced upregulation of IL-6 and ICAM-1 (human acinar cells) and procollagen I (human PSCs) was suppressed by pretreatment with the PTH1R antagonist, PTHrP (7-34). These findings establish PTHrP as a novel mediator of inflammation and fibrosis associated with CP. Acinar cell-secreted PTHrP modulates acinar cell function via its effects on proinflammatory cytokine release and functions via a paracrine pathway to activate PSCs.

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.

Role of bone marrow-derived mesenchymal stem cells in a rat model of severe acute pancreatitis

AIM: To investigate the role and potential mechanisms of bone marrow mesenchymal stem cells (MSCs) in severe acute peritonitis (SAP).

METHODS: Pancreatic acinar cells from Sprague Dawley rats were randomly divided into three groups: non-sodium deoxycholate (SDOC) group (non-SODC group), SDOC group, and a MSCs intervention group (i.e., a co-culture system of MSCs and pancreatic acinar cells + SDOC). The cell survival rate, the concentration of malonaldehyde (MDA), the density of superoxide dismutase (SOD), serum amylase (AMS) secretion rate and lactate dehydrogenase (LDH) leakage rate were detected at various time points. In a separate study, Sprague Dawley rats were randomly divided into either an SAP group or an SAP + MSCs group. Serum AMS, MDA and SOD, interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α levels, intestinal mucosa injury scores and proliferating cells of small intestinal mucosa were measured at various time points after injecting either MSCs or saline into rats. In both studies, the protective effect of MSCs was evaluated.

RESULTS: In vitro, The cell survival rate of pancreatic acinar cells and the density of SOD were significantly reduced, and the concentration of MDA, AMS secretion rate and LDH leakage rate were significantly increased in the SDOC group compared with the MSCs intervention group and the Non-SDOC group at each time point. In vivo, Serum AMS, IL-6, TNF-α and MAD level in the SAP + MSCs group were lower than the SAP group; however serum IL-10 level was higher than the SAP group. Serum SOD level was higher than the SAP group at each time point, whereas a significant between-group difference in SOD level was only noted after 24 h. Intestinal mucosa injury scores was significantly reduced and the proliferating cells of small intestinal mucosa became obvious after injecting MSCs.

CONCLUSION: MSCs can effectively relieve injury to pancreatic acinar cells and small intestinal epithelium, promote the proliferation of enteric epithelium and repair of the mucosa, attenuate systemic inflammation in rats with SAP.

Role of parathyroid hormone-related protein in the pro-inflammatory and pro-fibrogenic response associated with acute pancreatitis

Pancreatitis is a common and potentially lethal necro-inflammatory disease with both acute and chronic manifestations. Current evidence suggests that the accumulated damage incurred during repeated bouts of acute pancreatitis (AP) can lead to chronic disease, which is associated with an increased risk of pancreatic cancer. While parathyroid hormone-related protein (PTHrP) exerts multiple effects in normal physiology and disease states, its function in pancreatitis has not been previously addressed. Here we show that PTHrP levels are transiently elevated in a mouse model of cerulein-induced AP. Treatment with alcohol, a risk factor for both AP and chronic pancreatitis (CP), also increases PTHrP levels. These effects of cerulein and ethanol are evident in isolated primary acinar and stellate cells, as well as in the immortalized acinar and stellate cell lines AR42J and irPSCc3, respectively. Ethanol sensitizes acinar and stellate cells to the PTHrP-modulating effects of cerulein. Treatment of acinar cells with PTHrP (1-36) increases expression of the inflammatory mediators interleukin-6 (IL-6) and intracellular adhesion protein (ICAM-1), suggesting a potential autocrine loop. PTHrP also increases apoptosis in AR42J cells. Stellate cells mediate the fibrogenic response associated with pancreatitis; PTHrP (1-36) increases procollagen I and fibronectin mRNA levels in both primary and immortalized stellate cells. The effects of cerulein and ethanol on levels of IL-6 and procollagen I are suppressed by the PTH1R antagonist, PTHrP (7-34). Together these studies identify PTHrP as a potential mediator of the inflammatory and fibrogenic responses associated with alcoholic pancreatitis.

Sesamol attenuates oxidative stress–mediated experimental acute pancreatitis in rats

Acute pancreatitis is a potentially fatal disease with no known cure. The initial events in acute pancreatitis may occur within the acinar cells. We examined the effect of sesamol on (i) a cerulein-induced pancreatic acinar cancer cell line, AR42J, and (ii) cerulein-induced experimental acute pancreatitis in rats. Sesamol inhibited amylase activity and increased cell survival. It also inhibited medium lipid peroxidation and 8-hydroxydeoxyguanosine in AR42J cells compared with the cerulein-alone groups. In addition, in cerulein-treated rats, sesamol inhibited serum amylase and lipase levels, pancreatic edema, and lipid peroxidation, but it increased pancreatic glutathione and nitric oxide levels. Thus, we hypothesize that sesamol attenuates cerulein-induced experimental acute pancreatitis by inhibiting the pancreatic acinar cell death associated with oxidative stress in rats.

Review article: pancreatic renin-angiotensin systems in health and disease

BACKGROUND

In addition to the circulating (endocrine) renin-angiotensin system (RAS), local renin-angiotensin systems are now known to exist in diverse cells and tissues. Amongst these, pancreatic renin-angiotensin systems have recently been identified and may play roles in the physiological regulation of pancreatic function, as well as being implicated in the pathogenesis of pancreatic diseases including diabetes, pancreatitis and pancreatic cancer.

AIM

To review and summarise current knowledge of pancreatic renin-angiotensin systems.

METHODS

We performed an extensive PubMed, Medline and online review of all relevant literature.

RESULTS

Pancreatic RAS appear to play various roles in the regulation of pancreatic physiology and pathophysiology. Ang II may play a role in the development of pancreatic ductal adenocarcinoma, via stimulation of angiogenesis and prevention of chemotherapy toxicity, as well as in the initiation and propagation of acute pancreatitis (AP); whereas, RAS antagonism is capable of preventing new-onset diabetes and improving glycaemic control in diabetic patients. Current evidence for the roles of pancreatic RAS is largely based upon cell and animal models, whilst definitive evidence from human studies remains lacking.

CONCLUSIONS

The therapeutic potential for RAS antagonism, using cheap and widely available agents, and may be untapped and such roles are worthy of active investigation in diverse pancreatic disease states.

Preprotachykinin-A gene deletion regulates hydrogen sulfide-induced toll-like receptor 4 signaling pathway in cerulein-treated pancreatic acinar cells

OBJECTIVE

This study aimed to determine the effect of hydrogen sulfide (H2S) on Toll-like receptor 4 (TLR4)-mediated innate immune signaling in acute pancreatitis (AP) via substance P.

METHODS

Male Swiss mice were treated with hourly intraperitoneal injections of cerulein (50 μg/kg) for 10 hours. dl-propargylglycine ([PAG] 100 mg/kg, intraperitoneally), an inhibitor of H2S formation, was administered 1 hour after the induction of AP. Pancreatic acinar cells from male preprotachykinin-A gene-knockout mice (PPTA) and their wild-type counterparts were incubated with or without cerulein (10 M for 60 minutes). To better understand the effect of H2S in inflammation, acinar cells were stimulated with cerulein after addition of H2S donor, sodium hydrosulfide. In addition, cerulein-treated pancreatic acinar cells were pretreated with PAG (30 μM) for 1 hour.

RESULTS

The H2S inhibitor PAG eliminated TLR4, interleukin 1 receptor-associated kinase 4, tumor necrosis factor receptor-associated factor 6, and nuclear factor-κB (NF-κB) levels in in vitro and in vivo models of cerulein-induced AP. PPTA gene deletion reduced TLR4, myeloid differentiation factor 88, interleukin 1 receptor-associated kinase 4, tumor necrosis factor receptor-associated factor 6, and NF-κB in cerulein-treated pancreatic acinar cells, whereas administration of sodium hydrosulfide resulted in a further rise in TLR4 and NF-κB levels in cerulein-treated pancreatic acinar cells.

CONCLUSION

The present findings show for the first time that in AP, H2S may up-regulate the TLR4 pathway and NF-κB via substance P.

Down-regulation of HSP60 expression by RNAi increases lipopolysaccharide- and cerulein-induced damages on isolated rat pancreatic tissues

The objective of this study was to investigate the function of heat shock protein 60 (HSP60) on pancreatic tissues by applying HSP60 small interfering RNA (siRNA) to reduce HSP60 expression. Rat pancreas was isolated and pancreatic tissue snips were prepared, cultured, and stimulated with low and high concentrations of cerulein (10(-11) and 10(-5) mol/L) or lipopolysaccharide (LPS, 10 and 20 μg/mL). Before the stimulation and 1 and 4 h after the stimulation, the viability and the level of trypsinogen activation peptide (TAP) in the tissue fragments were determined and the levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) in the culture supernatants were measured. Real-time PCR and Western blotting were used to evaluate the HSP60 mRNA and protein expression. After the administration of siRNA to inhibit HSP60 expression in the isolated tissues, these injury parameters were measured and compared. The pancreatic tissues in the control (mock-interfering) group showed a decreased viability to varying degrees after being stimulated with cerulein or LPS, and the levels of TAP, TNF-α, and IL-6 increased significantly (p < 0.05) in the tissues and/or in the culture supernatant. The expressions of HSP60 mRNA and protein were raised moderately after stimulating 1 h with low concentrations of cerulein or LPS, but decreased with high concentrations of the toxicants. In particular, the expression of HSP60 protein was reduced significantly (p < 0.05) when the tissues were stimulated by the two toxicants for 4 h. In contrast, the tissue fragments in which HSP60 siRNA was applied showed much lower tissue viability (p < 0.01) and higher levels of TNF-a, IL-6, and TAP (p < 0.01) in the tissues or culture supernatant after stimulating with the toxicants at the same dose and for the same time duration as compared with those of the control groups (p < 0.05). The results indicated that both cerulein and LPS can induce injuries on isolated pancreatic tissues, but the induction effects are dependent on the duration of the stimulation and on the concentrations of the toxicants. HSP60 siRNA reduces HSP60 expression and worsens the cerulein- or LPS-induced injuries on isolated pancreatic tissues, suggesting that HSP60 has a protective effect on pancreatic tissues against these toxicants.

TRAF6 as the key adaptor of TLR4 signaling pathway is involved in acute pancreatitis

OBJECTIVES

To study the potential role of tumor necrosis factor receptor-associated factor 6 (TRAF6) as the key adaptor of the toll-like receptor 4 (TLR4) signaling pathway in acute pancreatitis (AP) in mice.

METHODS

Acute pancreatitis was induced by 7 intraperitoneal injections of cerulein in TLR4-deficient (TLR4-Def) and TLR4 wild-type (TLR4-WT) mice. Inflammatory severity was scored and evaluated based on pathological study. TRAF6 expression was determined by reverse transcriptase polymerase chain reaction, Western blot, and immunohistochemistry.

RESULTS

Acute pancreatitis was successfully induced in both mice strains, but the inflammatory progression was different. In TLR4-Def mice, pancreatic inflammation was blunt and mild first, then became increasingly intensive and peaked at the later stage, whereas in the TLR4-WT mice, the response was fast initiated and peaked at the early stage of AP, then alleviated gradually. TRAF6 expression in TLR4-Def mice was significantly higher than that in the TLR4-WT mice. Immunohistochemistry located TRAF6 expressed mainly in the pancreatic acinar cells.

CONCLUSIONS

The TLR4-TRAF6 signaling pathway is critically involved in AP. Other signaling pathways beyond TLR4 may participate in the pancreatic inflammatory process via TRAF6. As a convergence point of the TLR4-dependent and the TLR4-independent signaling pathways, TRAF6 plays an important role in AP.

Down-regulation of tumor necrosis factor-associated factor 6 is associated with progression of acute pancreatitis complicating lung injury in mice

Acute lung injury is one of the critical complications of acute pancreatitis (AP). Tumor necrosis factor-associated factor 6 (TRAF6) is a key adaptor that regulates various inflammatory signaling pathways, including those mediated by Toll-like receptors (TLRs). This study was performed to investigate the potential role of TRAF6 in the pathogenesis of AP and pancreatitis-associated acute lung injury using a mouse model of caerulein-induced AP (CAP). CAP was induced by intraperitoneal injection of caerulein hourly for 7 times (50 microg/kg), and control mice were treated with saline of the same volume. Typical pancreatic and lung inflammation was observed in the early stage (1 h) of CAP, as judged by morphological changes. Likewise, in CAP mice, the pancreatic myeloperoxidase activity and serum levels of interleukin-6 and interleukin-10 were significantly increased after 2 h, peaked at 4h, and then decreased by 24 h. The expression of TRAF6 was then studied by real time-PCR, immunohistochemistry, and Western blot analysis. Compared with control group, TRAF6 mRNA level was decreased in CAP group within the first 12 h, and then significantly increased after 24 h, which was in accordance with the protein level detected by Western blot analysis and immunohistochemistry. Moreover, TRAF6 protein was expressed in both pancreatic acinar cells and lung bronchial epithelial cells. In conclusion, the down-regulation of TRAF6 was associated with increased inflammatory severity in the pancreas and lung, suggesting that TRAF6 is involved in the anti-inflammatory process during AP. TRAF6 may be a potential molecular target for treating AP.

Potential role of the TLR4/IRAK-4 signaling pathway in the pathophysiology of acute pancreatitis in mice

OBJECTIVE AND DESIGN

Toll-like receptor 4 (TLR4) is potentially associated with acute pancreatitis (AP), but its exact role remains controversial. IL-1 receptor-associated kinase 4 (IRAK-4) is a common mediator of Toll-like receptors pathways, with an essential role in transducing downstream signals. This study investigates the potential role of the TLR4 pathway, in particular IRAK-4, in a murine model of AP.

METHODS

Acute pancreatitis was induced in wild-type and TLR4-deficient mice by intraperitoneal injections of caerulein (50 microg/kg). Pancreatic pathological scores and myeloperoxidase activity were dynamically measured, along with pancreatic TLR4 and IRAK-4 mRNA and protein.

RESULTS

In wild-type mice, pathological scores and myeloperoxidase activity were rapidly increased at 1, 2 and 4 h, followed by alleviation at 12 and 24 h. In TLR4-deficient mice, they were slightly increased within 2 h, but became more severe at 12 and 24 h. IRAK-4 mRNA and protein were significantly down-regulated at 1, 2 and 4 h in wild-type mice. Unexpectedly, TLR4-deficient mice showed more profound reductions of IRAK-4 mRNA and protein at the same time.

CONCLUSIONS

TLR4 deficiency delayed the initiation of pancreatitis, implying a potential role for TLR4 during AP. IRAK-4 might function during AP, but independently of TLR4.

Acute pancreatitis: animal models and recent advances in basic research

Acute pancreatitis (AP) is characterized by edema, acinar cell necrosis, hemorrhage, and severe inflammation of the pancreas. Patients with AP present with elevated blood and urine levels of pancreatic digestive enzymes, such as amylase and lipase. Severe AP may lead to systemic inflammatory response syndrome and multiorgan dysfunction syndrome, which account for the high mortality rate of AP. Although most (>80%) cases of AP are associated with gallstones and alcoholism, some are idiopathic. Although the pathogenesis of AP has not yet been elucidated, a common feature is the premature activation of trypsinogen within pancreatic tissues, which triggers autodigestion of the gland. Recent advances in basic research suggest that etiologic factors including cyclooxygenase-2, substance P, and angiotensin II may have novel roles in this disease. Basic research data obtained thus far have been based on animal models of AP ranging from mild edematous pancreatitis to severe necrotizing pancreatitis. In view of this, an adequate selection of experimental animal models is of paramount importance. Notwithstanding these animal models, it should be emphasized that none of these models mimic the clinical situation where varying degrees of severity usually occur. In this review, commonly used animal models of AP will be critically evaluated. A discussion of recent advances in our knowledge about AP risk factors is also included.